* GB785393 (A)

Description: GB785393 (A) ? 1957-10-30

Pigmented styrene polymers

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

C0MiETE SPEC1FICAON EDighaented Styrene Polymer$ -TD UNION CARBIDE CORPORATION, formerly Union Carbide and Carbon Corporation, a corporation organised under the laws of the State of New York, United States of America, of 30 East 42nd Street, New York, State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to improvements in the pigmentation of moldable or extrudable styrene polymer compositions with titanium dioxide. The use of titanium dioxide as a white pigment in molding and extrusion compositions is highly desirable as the hiding power of titanium dioxide in either the rutile on the anatase form is severalfold that of other commonly used white pigments as for example zinc sulphide, zinc oxide, antimony oxide and basic carbonate white lead. Hence, to obtain any desired degree of whiteness in a molded or extruded article, considerably smaller quantities of titanium dioxide are required to be incorporated in the molding composition than is the case with the other aforementioned white pigments. Unsatisfactory results have been encountered, however, in the use of

convention titanium dioxide pigment in styrene molding or extrusion compositions wherein the essential thermoplastic component is a polymer of styrene or its homologues such as alpha-methyl styrene and chlorostyrene or a copolymer of styrene and a monomer such as acrylonitrile or butadiene. For reasons not known or fully appreciated, it appears that the use of titanium dioxide pigment in styrene molding or extrusion compositions is attended by anomalous colour effects which in part are apparently due to exposure of the styrene composition to the heat and pressures necessary to mold or extrude the composition. Frequently the molded article when examined immediately upon ejection or discharge from the molding press or extruder exhibits dark strealts interspersed between areas of the desired whiteness. Such streaks are often present throughout the thickness of the molded piece, and occasionally occur even on the surface. Strangely upon aging of the molded article at room temperature, the streaks would tend to partly or completely disappear after several weeks to months. Another problem encountered in the use of titanium dioxide pigment is that the color brightness of the molded piece as viewed by the eye and confirmed by spectrophotometer measurements was highly variable depending on the thermal and pressure conditions to which the molded article was subjected to during the molding or extrusion operation. In general, higher moulding temperatures and pressures appeared to produce molded pieces of lower color brightness. But again, in many instances upon aging of the molded article the color brightness would tend to improve. Accordingly, the principal object of this invention is the production of styrene polymer molding or extrusion compositions pigmented with a titanium dioxide pigment, said compositions in molded or extruded form being characterized by freedom from color streaking and having a stable color brightness upon aging of the molded article. It has now been found that by treating commercial white titanium dioxide pigment of either the rutile or anatase types with a small amount of a hydrolyzable organosilane, hydrolyzing the silane after application to the pigment to form silanols which are condensed to form polysiloxanes, that the resultant polysiloxane coated pigment when incorporated in a styrene molding or extrusion composition surprisingly effects uniform and stable coloration in articles molded or extruded therefrom, At least a 1 per cent quantity of a hydrolyzable organosilane on the weight of the titanium dioxide pigment is required to effect color stabilization under molding or extrusion conditions. Above 4% by weight of silane causes no appreciable gain in effectiveness. The oganosilane treated titanium dioxide pigment will constitute between

one percent and ten percent by weight of the molding or extrusion composition. The use of titanium dioxide in amounts more than 10 /g by weight is unnecessary for a pigmenting function and is undesirable in that it unduly stiffens the composition, thus impairing its moldability, and tends to produce articles of a dull finish. When the titanium dioxide pigment is the sole coloring agent in the composition, quantities between 1% and 5% by weight usually impart adequate opaque whiteness and colorbrslghtness to the molded composition. Amounts of titanium dioxide pigment less than one percent by weight of the composition as for example 0.1% produce useful translucent white articles. Obviously, if the styrene polymer or copolymer is itself highly colored, more of the titanium dioxide pigment may be required to obtain or match a desired degree of whiteness and opaqueness. Furthermore, the use of titanium dioxide pigment treated as herein described is not to be considered restricted solely to the production of articles having a white coloration. Thus for example it has been found that the same advantages, namely color-brightness, stability and absence of objectionable streaking is to be had with pastel colored compositions containing in addition to the treated titanium dioxide, another pigment or pigments in amounts to produce the desired color or shade. Since titanium dioxide either treated with an organosilane or untreated is somewhat abrasive in its action on molding equipment surfaces, there is a likelihood for another type of streaking to occur in molded pieces. Such streaking is believed due to the scouring action of the titanium dioxide causing material to be abraded from the heating surfaces of the forming equipment. This abraded material becomes mixed with the molding composition during the molding operation and its presence can be visually noted in the molded article. Streaking caused by a braded material is more likely to occur in injection molding operations than in compression molding or extruding operations because of the more severe heat and pressure conditions under which injection molding is conducted. Streaking caused by abraded material can be satisfactorily eliminated by incorporating a small amount of lubricant in the styrene molding composition. Suitable lubricants include waxes of synthetic or natural origin, as for example waxy polyethylene oxides, beeswax, microcrystalline wax and carnauba wax; and metal soaps such as zinc stearate, aluminium stearate and sodium palmitate. The amount of lubricant generally required lies between about 0.01% and 0.05% by weight of the styrene composition when the lubricant is applied as an external surface coating on the molding material granules. When the

lubricant is incorporated internally, as by intensive hot compounding with heat-softened styrene polymer, then somewhat more lubricant is required in order to prevent abrasion. With an internal lubricant, amounts thereof between about 0.15% and 10% by weight of the composition are indicated for adequate protection against the abrasive action of titanium oxide. Ordinarily a lubricant is not essential when the styrene polymer composition is processed in an extruder or by compression molding. The presence of a lubricant is highly desirable, however, in compositions intended for injection molding purposes and particularly when high molding temperatures and pressures are employed. The hydrolysis and condensation of organosilanes to form polysiloxanes is fairly well known. The organotrichlorosilanes are readily hydrolyzed to silanois upon mere exposure to the moisture normally present in air. Accordingly, simple mixing of such silanes with the titanium dioxide pigment in the presence of air will cause hydrolysis of the silane. The water for hydrolysis may be in part at least supplied by the minute quantities of water which have been absorbed in the pigment surfaces during storage of the pigment after manufacture. Condensation of the silanols formed by the hydrolysis step to polysiloxanes may then be promoted by heating the silane treated pigment to moderate temperatures as for example, 100" C. to 300 C. The organotrialkoxylsilanes do not hydrolyze as readily as the organotrichlorosilanes and, therefore, conventional acid or basic catalysts are preferably used with the alkoxysilanes to catalyze the hydrolysis of the ether groups. Suitable catalysts for promoting hydrolysis include sodium hydroxide, hydrociloric acid, sulphuric acid, ammonium hydroxide, and amines such as triethanolamine and dimethylamine. Table I, shown below describes the results of treating white rutile titanium dioxide piggents with several different trifunctional organosilanes including alkyl and alkenyl tri chlorosilanes and alkyl, alkenyl and aryl trialkoxysilanes. The column on the right records the degree of streaking as determined by visual observation in white polystyrene articles molded from a composition containing 2% by weight of silane treated titanium dioxide pigment. The effect of treating the titanium dioxide pigment with ethyl silicate and the results of an untreated titanium dioxide pigment in white polystyrene articles are presented for purposes of comparison. TABLE I Degree of streaking Orrganosilane used in molded article Vinyltrichiorosilane - - - Very little or no streaking Ethyltriethoxysilane - - - " " " " 33 Methyltrichiorosilane - - -

Slight streaking Vinyltriethoxysilane - - - 33 33 Phenyltriethoxysilane - - - 33 33 Vinyltri-B methoxyethoxysilaue 33 33 Amyltriethoxysilane - - - Noticeable streaking Ethyltrichlorosilane - - - " 33 Phenyltributoxysilane - - - " 33 Nonyltriethoxysilane - - 33 " " Ethyl silicate - - - - Very bad streaking Untreated titanium dioxide - - 33 33 33 Pigment - - - - - " " " As shown in Table 13 the effectiveness of the organosilane treatment on the final molded article varies with the specific organosilane employed. In this connection it is also to be noted that without regard to the particular organosilane used the effect in reducing streaks in the final molded article is pronounced in comparison with an article colored by the untreated pigment or the pigment treated with ethyl silicate. It is the general practice to incorporate polymerization inhibitors into monomeric styrene in order to prevent premature polymerization. Consequently, prior to the polymerization operation it is necessary to remove the inhibitor so that the monomeric styrene will readily polymerize to form a plastic molding material. In the event that the inhibitor is incompletely removed, discoloration effects in the final molded article are likely to be encountered. White polystyrene articles colored by untreated titanium dioxide pigment were rendered commercially unacceptable by the presence of an unremoved polymerization inhibitor in the initial monomeric styrene. It has been found3 however, that titanium dioxide pigments treated according to the teachings of this invention serve to offset any discoloration effects due to the presence of an incompletely removed inhibitor, in addition to providing the benefinial effect in elminating streaking and improving light reflectance as already mentioned. The following methods serve to illustrate the formation of the polysiloxane coating on the particles of the titanium dioxide pigment:- METHOD A One thousand five hundred grams of titanium dioxide pigment were placed in a glass bottle. Sixty grams3 or 2%, based on the total weight of titanium dioxide of vinyltrichioro- silane were introduced into the bottle and followed by the addition of another 1500 grams of titanium dioxide pigment. The resulting mixture was stirred well with a glass rod and the bottle was loosely covered. The mixture was heated in an oven at 100" C. for two days and upon removal from the oven was ready for use.

Methyltrichiorosilane and ethyltrichlorosilane were separately used to treat titanium dioxide pigment in the manner described in Method A for the enhancement of the coloring characteristics of the pigment. Treatments by the method of Method A employing organosilanes other than the chlorosilanes resulted in little or no enhancement of the coloring qualities of the pigments untreated. The poor results obtained in treating pigments with organosilanes containing no chlorine reactive groups as found in chlorosilanes has been attributed to the lower reactivity of these other organosilanes. In order to promote the reactivity of silanes not containing highly reactive chlorine radicals, such as those contained in the trichlorosilanes, it is the customery practice to employ with trialkoxysilanes a basic catalyst, for example3 sodium hydroxide, potassium hydroxide, or quaternary ammonium bases. Therefore, as an alternative method for treating titanium dioxide pigments with organosilanes other than chlorosilanes the following example is presented: METHOD B A thick slurry was prepared from 3000 grams of commercial white rutile titanium dioxide pigment and enough methanol to completely submerge said pigment. To this slurry was added 60 grams of ethyltriethoxysilane (2% based on the pigment weight) and the mixture was stirred well. From 2.5 grams to 7.5 grams of sodium hydroxide dissolved in a small quantity of methanol was thereupon added and the resulting mixture was placed in an oven maintained at a temperature of 100" C. After thus removing the methanol by evaporation the pigment was ready for incorporation into a polystyrene molding compositiolL The method of treatment described in Method B was applied to the separate treat ments of titanium dioxide pigments with vinyltriethoxysilane, phenyltriethoxysilane, vinyl-fS- methoxyethoxysilane, amyltriethoxysilane, phenyltributoxysilane and nonyltriethoxysilane to provide enhanced coloring characteristics to the pigments. Although the amount of organosilanes, respectively employed in Methods A and B, were specified to be 2% of the pigment weight, treatments were also carried out in accordance with the Method A or Miethod B, depending upon the particular organosilane employed, with each of the organosilanes disclosed in Table I in the respective amounts of 1%, 2% and 4%, based on the weight of titanium dioxide, pigment being treated. In separate treatments of commercial white rutile and anatase titanium dioxide pigments with a par-ticular organosilane in the respective percentage amounts on the pigment weight basis of 1%, 2% and 4%, it was found

that the effects in eliminating streaking and pry sting color brightness became more pronounced as the amount of the organosilane used was increased from 1% to 4%. It was further discovered that while raising the amount Of the organosilane used in the treatment from 2% to 4X did increase the eiiectiveness of the treatment, such an increase in effectiveness was not proportional to the increase in the amount of organosilane used. Inasmuch as the 2% amount appears to produce optimum results in the pigment treatment, it is the preferred amount. Never-heless3 since other amounts are equally or more effective, the preference as to the 2% amount is not to be considered as limiting on this invention. In treatments of titanium dioxide pigments with less than 1, on a pigment weight basis, of any hydrolyzable organosilane listed in Table I, little or no effects on the coloring characteristics of the pigments were noted. When commercial titanium dioxide pigments were treated with more than 4%, based on the pigment weight, of a hydrolyzable organosilane, no increase in effectiveness over the treatment with 4% of the same organosilane resulted. In the latter case, it is suspected that any amount of the organosilane over 4% of the commercially graded titanium dioxide pigment weight is lost by vaporization during the treatment and, hence, does not contribute to the effectiveness of the treatment. Consequently, while amounts of hydrolyzable organosilanes in excess of 4% of commercially graded pigment weight may be employed in the treatments set forth herein any such excess does not advantageously contribute to the effective- ness of said treatments. The organosilane range of 1% to 4% is, therefore, preferred but the upper limit theresi, i.e. the 4 ", limit, is in no way intended to be restrictive upon this invention. The following examples are illustrative of several methods of incorporating treated titanium dioxide pigment into polystyrene to form a molding composition : - EXAMPLE 1 A master batch containing 60 parts of rutile titanium dioxide pigment treated in accordance with - Method B with -, of vinyltriethoxysilane, based on the weight ot pigment, and 40 parts ot polystyrene was prepared and compounded for ten minutes in a heated Banbury mixer. The hot compound was then transferred to head mixing oils and mi:d ior 10 minutes to complete the dispersion of the pigment into the polystyrene. Tne compound was then sleeted, granulated and mixed with a sulilcient amount of polystyrene to reduce the pigment contend to 1.4 percent of the total mixture. The resulting mixture was then compounded in a compounding machine. Extruded articles produced from a composition prepared in accordance with this example were markedly

superior in color brightness and the absence ot streaks to articles molded from composkion containing untreated titanium dioxide pigment. F-XAMPLE 2 A molding composition was prepared. in a manner similar to that described in Example 1 using, however, a master batch containing 75 parts of polystyrene and 25 parts of rutile titanium dioxide pigment treated in accordance with the Method B with 2%, based on the weight of pigment, of vinyltriethoxysilane. An injection molding composition was then prepared by mixing the master batch with sufficient polystyrene to reduce the pigment content to 2.0 , by weight of the composition. After fituang and granulating the mixture 0.25 parts of zinc stearate were added and mixed with 100 parts of the composition as an external lubricant. Articles injection molded from the molding csvmposition of this example were found to be superior in color characteristics to articles made from compositions having untreated titanium dioxide pigment. EXAMPLri 3 Sixty parts by weight of titanium dioxide pigment treated by Method B with 2%, based on pigment weight, of vinyltriethoxysilane and 40 parts by weight of polystyrene were compounded in a two roll mill to form a master batch. Fifteen parts by weight of this master batch were then compounded with 25 parts by weight of a mixture of styrene and polystyrene in a weight ratio of 17 to 8, respectively. A composition having a titanium dioxide pigment content of 1.4% is then produced by injecting a sufficient quantity of the resulting compounded mixture into the hot resin stream of a polystyrene production line. The composition on discharge was granulated and mixed rrith 0.25 , by weight of zinc stearate as an external lubricant This composition yielded streak-free injection molded articles. EXAMPLE 4 A master batch containing 80 parts by weight of titanium dioxide pigment treated with 2%, based on the weight of pigment, of vinyltriethoxysilane in the manner set forth fr: Method B and 20 parts by weight of polystyrene was prepared on a two roll mill, then 11.25 parts by weight of the master batch. thus prepared, were compounded with 28.75 parts by weight of a mixture of styrene and polystyrene based on the weight ratio of 17 to 11.75, respectively. The compounded mixture was then injected into the hot resin stream of a polystyrene production line in a sufficient quantity to produce a molding composition containing approximately 1.4% of titanium dioxide pigment. Zinc stearate was added as described in Example 3. It is generally recognized in the molding arts that molding

compositions made from master batches prepared in compounding machines or on a two roll mill and containing proportionately large amounts of pigments are not capable of providing molded articles having color characteristics comparable with articles produced from molding compositions prepared from master batches containing proportionately smaller amounts of pigments. In preparing molding compositions according to the present invention, a similar condition exists. For example, articles made from compositions prepared from a master batch described in Example 4, i.e. a master batch high in treated titanium dioxide pigment content, were inferior in color characteristics to articles produced from compositions prepared from a master batch described in Example 3, i.e. a master batch substantially lower in treated titanium dioxide pigment content. This inferiority in color characteristics appears to be caused by the excessive abrasion of the treated pigment particles contained in the master batch of high pigment content during the compounding procedure, although the like- lihood of other causes, such as the ease or difficulty in dispersing pigment particles in the polystyrene, have been postulated. In any event, while some uncertainty exists as to the exact cause of this condition, it is possible to remedy the condition by means of proper master batch formulations. EXAMPLE 5 A master batch was prepared by ball milling titanium dioxide pigment treated in accordance with Method B with 2%, based on the pigment weight, of vinyltriethoxysilane into a solution of polystyrene in styrene. The amount of this solution as well as its percentage composition was inconsequential so far as the color qualities of the final molding composition was concerned; these factors being determined by the physical characteristics of the particular ball milling equipment in use. When the pigment was well dispersed in the polystyrene solution, the resulting suspension was diluted with additional solution; the amount and percentage composition of said solution being determined by the degree of nudity required .or the particular pumping apparatus employed. The suspension was then injected into the molten resin stream of a polystyrene production line in such quantities that the resulting molding composition contained 1.4% of titanium dioxide pigment. Articles produced from a composition prepared in this manner were superior in color characteristics to articles colored with untreated titanium dioxide pigment and were equaL in color characteristics to the best articles molded from compositions prepared in accordance with Examples 1 to 4. EXAMPLE 6 An injection molding composition having a pastel yellow color was

prepared by hot milling together the following ingredients: % by weight Polystyrene - - - - 99.2238 pleated titanium dioxide of Ex. 2 - - ^ - - 0.50 Cadmium sulphide - - - 0.024 Cadmium sulphide selenide - 0.0022 After granulating the above milled composition, 0.25% by weight of zinc stearate was dusted on the granules as a lubricant. This composition produced streak-free injection molded articles having a stable color-brightness on aging. EXAMPLE 7 A titanium dioxide pigmented molding composition based on a styrene-acrylonitrile copolymer resin was prepared by dipersing 2.0 parts of rutile titanium dioxide treated with vinyltrichiorosilane as described in Method A in 98 parts by weight of styrene-acrylonitrile copolymer formed by copolymerizing 75 parts styrene with 25 parts acrylonitrile. The resultant composition produced satisfactory streak-free, white extruded articles as well as compression molded pieces. EXAMPLB 8 A synthetic rubber-modified polystyrene composition was prepared by milling together 30 parts by weight butadiene-styrene rubber (GRS) and 70 parts polystyrene. This composition was mixed with 6 parts of rutile titanium dioxide treated with a silane according to Method B and 0.5 parts zinc stearate. The resultant composition produced streak-free articles of uniform whiteness when injection molded. It is to be noted that the amount of titanium dioxide pigment in a master batch prepared in a ball mill, as described in Example 5, does not affect the color characteristics of a molding composition prepared from such a master batch. Whatever conditions existing on a two roll mill or a compounding machine to adversely influence the coloring properties of pigments contained in master batches processed in said roll mill or machine, are not present in a ball mill. Consequently, the need for critical master batch formulating. i.e. the need for determining the optimum pigment content in the master batch as illustrated in Examples 3 and 4 does not prevail when a ball mill is used in compounding the master batch as, for example, is described in Example 5. While certain of the Examples 1 to 5, pre sented above provide molding compositions having qualities superior to the molding compositions of other examples, it is to be noted that the compositions of every example possess beneficial qualities over

similar compositions containing untreated titanium dioxide pigment. Accordingly, these examples are not intended to limit the present invention, but are illustrative of the variety of compounding procedures available for preparing molding compositions of treated titamum dioxide pigment and polystyrene. Although Examples 1 to 5 are specifically concerned with the compounding of vinyltriethoxysilane treated titanium dioxide pigment, similar compounding procedures may be applied to titanium dioxide pigments treated with any one of the various hydrolyzable organosilanes, inclusive of those recited in Table I, in accordance with Methods A or B, depending upon the particular organosilane used, without departing from the fundamental concept of this invention. The titanium dioxide pigments susceptible to improvement by the invention herein described are those such as are ordinarily obtained by hydrolysis of an aqueous solution of titanium sulphate to form titanium hydroxide which on calcination at temperatures of about 600" C.800" C. yields the anatase form of titanium dioxide. By calcinin

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* GB785394 (A)

Description: GB785394 (A) ? 1957-10-30

Improvements relating to the manufacture of structures produced bydepositing fibrous elements

Description of GB785394 (A)

COMPLETE SPECIFICATION Improvements relating to the Manufacture of Structures Produced by Depositing Fibrous Elements

We, CHANGEWOOD CORPORATION, a Corporation organised under the laws of the State of Illinois, United States of America, of Suite 1160, 209 South La Salle Street, Chicago 4, County of Cook, State of Illinois, United States of America, do hereby declare the inInvention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the manufacture of structures produced by depositing of fibrous elements of small to substantial dimension in length or width and is more particularly concerned with new or improved method and apparatus causing fibrous elements of this nature to be deposited upon a collecting sur- face so as to form .a layer of predetermined thickness and distribution capable of being moulded into various objects, such as panels and boards, as by means of heat or pressure and by use of a binding agent where necessary or advisable. As used herein, the term "fibrous elements" is intended to include any free-flowing fibrous elements such as, or example, wooden wafers which may range in thickness from 0.0011 to 0.1215 inch or more and up to S inches in length or width, with or without tapered ends, or pieces of wooden veneer, or scraps thereof, cut into wafers or slivers of these dimensions, or chopped straw or bagasse or flax shives, and the like. The term also includes non-free-flowing elements such as textile staple fibres, glass and slag fibres an!d fibres produced from synthetic resinous materials and the like. As will be realised, the invention described and claimed herein embodies certain improvements in a means for flowing fibrous elements of normal size for deposition on to a moving surface to produce a fibrous web or structure. The invention also provides a simple and efficient means for deposition of the fibrous elements and a more uniform spreading of both large and small fibrous elements in the manufacture of fibrous structures. According to the present invention, a method of depositing fibrous elements on a collecting surface in the manufacture of layers having such elements in substantially uniform distribution, comprises advancing the collecting surface continually in one direction, feeding the fibrous elements at a uniform rate into one end of a distributor, moving the other end of the distributor continually and successively into either direct or indirect communication with a plurality of separate conveyors at a rate to de- liver substantially equal amounts of the fibrous elements to each, and positioning the outlets of the conveyors across and spaced above the collecting surface to deposit the fibrous elements in substantially uniform concentrations across the collecting surface.

According to another feature of the invention, apparatus for depositing fibrous elements on a collecting surface in the manufacture of layers having such elements in substantially uniform distribution, comprises a collecting surface movable continually in one direction, a distributor having an inlet and an outlet, means for feeding the fibrous elements at a uniform rate into the inlet of ,xhe distributor, a plurality of separate conveyors each having an outlet and of which the several outlets are positioned, suitably adjustably, in a row, or in spaced rows, extending transversely of the collecting surface, and means for moving the outlet of the distributor continually and successively into either direct or indirect communication with the conveyors to deliver substantially equal amounts of the fibrous elements to each for deposition in substantially uniform concentration across the collecting surface upon issuance from the outlet of each conveyor. Preferably, when the fibrous elements are free flowing, they are caused to move or flow gravitationally to, through or from the distributor. In the case of non-free-flowing elements, their movement by gravity to, through or from the distributor may be supplemented or replaced by a flow of air, or by moving con- veyor belt means or the like. In order to enable the invention to be readily understood, description will now be given by way of illustration, but not of limitation, of appropriate embodiments thereof shown more or less diagrammatically in the accompanying drawings in which: Figure 1 is a sectional side elevation of one form of apparatus according to this invention. Figure 2 a sectional plan of which the section is talons substantially along the line 2-2 of Figure 1, Figure 3 an enlarged fragmentary view of a portion of the apparatus shown in Figure 1, Figure 4 a schematic view of a modifica- tion which may b mad in the lower portion of the apparatus shown in Figure 1, Figure 5 .a front elevation of a modified form of apparatus according to this invention, Figure 6 a side elevation of another form of apparatus of the invention, and Figure 7 a plan of Figure 6 with parts omitted. In the embodiment illustrated in Figures 1 to 3, 10 indicates fibrous elements to be introduced continuously in metered amounts into an inlet chute 11 leading into a distributor 12. It is preferred to make use of an endless helt 13 upon which the fibrous elements 10 are uniformly spread. These elements are delivered into the chute 11 by a

picker 14 rotated in a counter-clockwise direction and having radially extending blades 15 which cooperate with the surface of the belt as it turns about the idler roller 16. The distributor 12 is of swan-neck form and tubular. It comprises an upper end portion 117 in communication with the underside of the chute 11 and an outlet end portion 18 positioned laterally with respect to 17 at the far end of a curvilinear main portion 19. Through the latter the fibrous elements are capable of movement or flow gravi@ationally from the inlet at 17 to the outlet at 18 which is presented substantially in the vertically downward direction. The outlet end portion 18 extends into a circular trough 20 having a radius corresponding to the offset of the outlet end portion *18 from the axis of the inlet end portion 117 about which the dis tributor 12 is rotated by means of a driving motor 2-1. The latter supports the distributor at such axis upon its drive shaft 22. The trough 20 has upright side walls 23, 24 and a bottom wall 25 which is formed with a plurality of openings 26, preferably equally spaced iand equally sized, each of which leads into a separate conveyor in the form of a down pipe 27 or conduit in communication with the opening and leading downwardly from the underside of the wall 25. The lower or outlet ends of the down pipes are slidably attached with a certain amount of play to .a rod or rods, such as 2S, by means of sleeves 29 or other brackets rigid with the down pipes. The rods 28 extend transversely above the surface 32 upon which the fibrous elements are to Ibe deposited and the adjustment allowed by the rods and the sleeves 29 permits the lower end portions of the down pipes ItO be secured to the rods in side by side relation to space the outlet ends across the collecting surface. Clamping means, such as setscrews (not shown) may be used for securing .the sleeves 29 to the rods 28 when in adjusted position. Suirably, the outlets of the down pipes are disposed as shown so that their axes are uniformly spaced apart transversely of the collecting surface. 'In order to arrest the downward flight of the fibrous elements upon issuing from the outlet end of the down pipes 27 and in order to spread the elements for deposition substantially uniformly across the collecting surface 32 without disturbing the fibrous elements previously deposited thereon or deposited by adjacent conveyors, a splash plate 30, Figures 1, 3 and 4, is secured to that end of each down pipe so as to extend downwardly therefrom in angular relation into the path of the fibrous elements issuing from the down pipes. These splash plates comprise relatively flat (Figures 1 and 4) or corrugated (Figure 3) rigid panels with a swivel connection 31, such as a ball and socket, at the upper end to the lower end of the

corresponding down pipe, or a bracket thereon, so as to enable angular adjustment of the plates both in a vertical plane and in a crosswise plane, to control the deflection of the fibrous elements for intermingling with one another and to avoid the formation of furrows as the fibrous elements are deposited to form a layer on the collecting surface 32. The latter may be an endless belt or screen but, for gravity-deposited elements, it is preferred to constitute it by lattice plates positioned end to end in continuous relation. The collecting surface is moved constantly in one direction and subsequently the layer of fibres with an added binding agent is moulded thereon to produce panels or boards or other desired objects. In most cases it is desirable to provide a series of directing troughs 33, preferably of V section, positioned in the space between the splash plates 30 and the ends of the down pipes 27 so as to cooperate with the splash plates in positively controlling the location of the streams of fibrous elements issuing from the relatively large and round down pipes 27. For this purpose, the directing troughs are disposed in alignment with the lower end of the down pipes and are preferably positioned to incline at .an opposite angle to the cooperating splash plates beneath them to cause revernal of the direction of movement of the fibrous elements during travel from the douse pipes and the splash plates on to the surface 32. These troughs may also be supported by ball and socket parts 34. In operation, fibrous elements, 10 advanced in metered amounts on belt 13 are displaced into the delivery chute 11 by the radially extending arms 15 of the picker 14. The fibrous elements thus introduced into the chute 11 travel downwardly through the tubular distributor 12 which is constantly being rotated by motor 21 thereby to parcel out the fibrous elements in substantially uniform amounts about the circular trough 20. The distributed elements pass through the openings 26 in the bottom wall 25 of the trough 20 into the conveyor down pipes 2.7 through which they fall by gravity toward the surface of the collecting surface 32. Since the distributor parcels out the fibrous elements for delivery in substantially equal amounts to each of the openings 2-6, it will be apparent that the down' pipes, when arranged in side by side relation at the delivery end, will distribute the frbrous elements substantially equally across the Icollect- ing surface and the directing troughs 33 land the splash plates 30 cooperating therewith will so control their movements as to gently lay the fibrous elements flatwise and in a desired inter- mingling relationship on to the collecting surface in a layer 35 of substantially uniform thickness. Should furrows form because of non-uniform distribution, the splash

plates 30 or the directing troughs 33 may be adjusted to deflect the fibrous elements in one direction or the other, or the down pipes 27 or directing troughs may be individually adjusted laterally on the cross rods 28 to over-come such nonuniformity. Depending upon the number of down pipes and the thickness of the layer 35 of fibrous elements to be deposited3 the outlet ends of the down pipes may be arranged in loae or more rows crosswise of the collecting wall, such as in two rows illustrated in Figure 1, or in four rows according to the modification shown in Figure 4. When arranged in more than one row, it is expedient to arrange the splash plates to deflect the fibrous elements in the direction towards each other to achieve a desired intermingled relationship on the collecting surface. While lateral distribution across the collecting surface may he achieved by proper adjustment of the down pipes, it has been found that the coverage provided by the down pipes can be greatly broadened and reduction of the number of down pipes made possible, by use of splash plates and directing troughs as described. In order to secure better lateral spreading of the fibrous elements, more than one tier of splash plates arranged so as to cause more than one reversal of direction of the falling streams of elements may be provided. According to the embodiment of the invention shown in Figure 5, instead of securing distribution and delivery of equal amounts of fibrous elements in the conveyors or down pipes by means of a rotatable distributor operating in a circular trough, as described in regard to Figures 1 and 2, a somewhat similar kind of distribution may be obtained with an oscillatory distributor formed of an elongate tubular member 40 pivoted at its upper end, as at 41, to the end of the inlet chute 11. The lower end portion 42 of the distributor 40 reciprocates throughout its arcuate movement in an arcuate trough 43 having openings spaced apart longitudinally in the bottom wall thereof with each opening in communication with a separate conveyor or down pipe 27a. Various means may be provided for reciprocation of the distributor 40, depending upon the rate of movement desired in a particular portion of the trough and variation in movement to achieve more uniform distribution of fibrous elements for feeding into the down pipes. For example, as illustrated schematically in Figure 5, the distributor 40 may be rocked about its pivot 41 in simple harmonic motion by means of a crank arm 44 pivoted at one end on a pin 45 secured to an intermediate portion of the distributor and having the other end pivoted on a pin 416 offset from the axis of rotation of a wheel 47 rotatably mounted on a stub shaft 48. The wheel 47 is driven by means of an electric motor 49 with which it is operatively connected by belt

50. Movement of the distributor at a more constant speed may be achieved by la modification of the device thus described wherein the other end of the crank arm 44 is pivoted on a link of an endless member 51 in the form of a chain operating at constant speed about sprockets 52 and 53. As described in connection with the first embodiment, the lower end portion of the down pipes 27a may be secured in one or more rows extending crosswise over the collecting surface 32. The spaced relation between the openings in the bottom wall of the arcuate trough 43 may be compensated to account for the fact that while the rate of delivery of fibrous elements from the distributor 40 will be constant and uniform, the linear speed at which the delivery end of the distributor moves through the trough 43 may vary from a higher speed at the centre, but, in any case, to a lower speed or dwell at the end, whereby a greater number of such elements will be delivered in the region towards and at the ends of the trough. By decreasing the size of the openings and increasing the number of epen- ings and down pipes towards and at the ends of the trough and by adjusting the width of the openings in inverse proportion to the time of traverse of the delivery end of the distribu@or over the openings, the amount of fibrous elements entering each opening for passage through the conveyors or down pipes 27 may be kept substantially uniform. In general, the spacing of the openings in the trough is arranged to relate to the motion of the outlet at 42 and the width of the openings at any part of the trough is inversely proportional to the relative speed of this outlet over that part with respect to its speed over other parts of the trough, that is, .the widths are uniform where the speed is uniform and the widths are approximately that of a sine-wave when the distributor swings in a simple harmonic motion. Similar considerations, of course, would apply to the previously described embodiments of the invention. As in the first embodiment, the down pipes 27a in Figure 5 are preferably provided at their lower ends with splash plates 30 positioned to extend longitudinally tat a desired downward .tilt across the outlet end and lasso, if desirable, with directing troughs (not shown), which cooperate therewith to control positively the posilotion of the streams and lay the fibrous elements in a controlled series of streams gently dn posi- tion upon the collecting surface and which can be adjusted to obviate small non-uniformities in the rate of delivery of the elements from adjacent down pipes. It will be evident from the foregoing deascription that there is provided a new and inaproved method and apparatus for the handling of fibrous elements of substantial dimension for deposition thereof to

form a uniform layer with the fibrous elements in intermingled relationship lor use in moulding into a strong and well-integrated panel, board or other moulded structure. It will be apparent that the apparatus described herein eliminates possibilities of the fibrous elements becoming lodged in restricted distributor openings so as to interfere with the uniform distribution thereof in the manufacture of such fibrous structures and that means are provided for gently and uniformly laying the fibrous elements on to a collecting surface in a desired intermingled relationship with la minimum amount of equipment .and in such manner as to avoid the necessity for the use of highly skilled labour to effect the operations involved. It will be understood that changes may be made in the construction, arrangement and operation without departing from the scope of the invention herein defined and claimed. For example, instead of employing the picker 14 in introducing the fibrous elements into the inlet chute 11, a brush roller may be arranged opposite, to and slightly spaced from the conveyor roller 16 and to be operative at a suffi- ciently high peripheral speed, in comparison with the roller 1i6, to cause a desirable volume of air to enter the chute along with the fibrous elements to supplement the gravitational movement of the fibrous elements through the distributor and the down pipes. Alternatively, an impeller or iblower such as 70, Figure 5, could be used to supply the air to the inlet chute 11 for the fibrous elements instead of the rotatable brush roller. Such supplementary use of 'air flow is advantageous when the fibrous elements have a high ratio of length to thickness, for instance very fine glass or slag fibres synthetic resin fibres, or cotton, wool or other stable fibres which tend to form aggregates. When such an air flow is used, a foraminous moving surface 32 for the deposited web is provided, as shown diagrammatically in Figure 5, land suction means such as a box 71 and exhaust fan 72, Figure 5, are adopted for withdrawing air from its underside opposite .the outlet ends of the down pipes, to accommodate the flow of air in the desired volume either continuously or ait appropriate timing through the distributor and down pipes and to hold the deposited fibres in their -inter- mingled relationship on the collecting surface during passage through the fibre depositing zone of the apparatus. In the constructions of apparatus above particularly described, the outlet of the distributor is moved continually and successively into direct communication with the inlets such as 26, of the several conveyors 27 cr 2.7a. Figures 6 and 17 illustrate a construction in which there is indirect communication with .the inlets of the conveyors, which latter take the form of a series of endless travelling belts or the like 54.

The distributor comprises an endless .travelling belt or the like 55 mounted on a frame 56 fixedly carried by the vertical shaft 57 of a geared motor 58. The constant stream of fibrous elements 10 is delivered from the belt 13 on to the distributor belt or the like by a rotatable brush 59. The layer 60 thus formed on the belt or the like 55 is brushed off the latter by a rotatable brush 61 mounted on the rotatable frame 56. The fibrous elements are thus delivered into equally sized openings 62 in a circular trough 53 from which rhe elements drop down spouts 64 to the several conveyors 54. Thus the outlet of the distributor delivers the fibrous elements indirectly by way of the down-spouts 64 to the conveyors, and because the down-spouts 64 are disposed about the axis of the trough 633 the outlets from these down- spouts are disposed at different points longitudinally of the different conveyor belts or the like 54 as will be realised. The fibrous elements are kept in lateral position on these belts or the like by providing the latter with upstanding side members 65, which, with the belts or the like, in effect form ducts for travel of the fibrous elements. Preferably, the conveyor belts or the like 54 are moved at a speed much less than the moving collecting surface 32 .and because of this the fibrous elements build up to an appreciable thickness on these belts or the like. In each of the conveyors or ducts 54, 65, the layer 66 of fibrous elements is smoothed out by backwardly rotating rakes or brush rolls 67 and the conjoined fibrous elements are finally brushed off the conveyors on to the collecting surface 32 by a rotating brush 68 to form the layer 35. It will be seen that the belts or the like 54 are illustrated in two tiers. In practice, there could be more belts or the like than shown in the tiers and several tiers could be used so as better to permit the bringing of fibrous elements to adjacent belts or the like from opposite openings in the trough 63 and thus smooth out any irregularities introduced by the feed to and from the distributor 55-56. Arrangement (not shown) may be made for moving the delivery ends or outlets of the conveyors laterally by slight amounts to promote uniform deposition of the fibrous elements in the layer 35 on the collecting surface 32. Or, instead, this could be provided for by adjusting the effective width of the openings 62 in the trough 63. For instance, a series of plates, such as 69, could be used hinged about the radial edges of the openings to be adjusted in opposite directions as shown by the arrows at one of the plates in Figure 7; or provision could be made for raising up the trough 63 and adjusting the points of discharge of the down-isipout 64 so as to vary the quantity of fibrous elements delivered to the belts or the like 54. The modification shown in Figures 6 and 7 is especially suitable for use when long fragile fibrous elements like fibres of mineral wool are

to be dealt with. It will be appreciated that instead of employing the endless belt 13 and the devices 14, 59 or the like for delivering the fibrous elements to the distributor, other devices may be employed to the desired end, the broad aim of the invention of depositing fibrous elements as a uniform structure on a moving collecting surface being attainable by the invention whether the fibrous elements be conveyed from the distributor, through it, or to it, by gravity, by air stream or by conveyor belts or the like, or by a combination thereof, suited to the fibrous elements being handled. What we claim is: - 1. Method of depositing fibrous elements on a collecting surface in the manufacture of layers having such elements in substantially uniform distribution, comprising advancing the collecting surface continually in one direction, feeding the fibrous elements at a uniform rate into one end of la distributor, moving the other end of the distributor continually and successively into either direct or indirect communication with a plurality of separate conveyors at a rate to deliver substantially equal amounts of the fibrous elements to each, and positioning the outlets of the conveyors across and spaced above the collecting surface to deposit the fibrous elements in substantially uniform concentrations across the collecting surface. 2. Method according to claim 1, wherein the fibrous elements are caused to move or flow to, through, or from the distributor gravitationally, or by a flow of air, or by moving conveyor belt means or the like. 3. Method according to claim 2, wherein the movement of the fibrous elements by gravity to, through or from the distributor is sup plemented by a flow of air, or by moving conveyor belt means or the like. 4. Method according to any of the preceding claims, wherein the distributor is operated to move its outlet end continually over a surface having a plurality of openings in communication with the inlets of said separate conveyors. 5. Method according to claim 4 wherein the outlet end of the distributor has a constart traversing period over the openings leading to the inlets of the said separate conveyors. 16.. Method according to claim i4 or claim 5, wherein the axes of the outlets of the said separate conveyors are positioned in predetermined spaced apart relation across the upper side of the collecting surface. 7. Method according to any of the

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785395 (A)

Description: GB785395 (A) ? 1957-10-30

Improvements in or relating to automobile automatic clutches

Description of GB785395 (A)

PATENT SPECIFICATION Date of Application and filing Complete Specification: Sept 28, 1955. 785,395 No 27671/55. 4 B a W l | Application made in France on Sept 28, 1954. \_____ Complete Specification Published: Oct30, 1957. Index at acceptance:-Class 80 ( 2), C 1 C( 1:4 C 9:10), C 1 E( 2:3:6:7), D( 3 C:3 K:10), P( 1 J 1 A O 1 J 3 B:1 X:4). International Classification:-FO 6 d, h. COMPLETE SPECIFICATION Improvements in or relating to Automobile Automatic Clutches We, SOCIETE ANO Nx YME FRANCAISE Du FERODO, of 64 Avenue de la Grande Armee, Paris 17 eme, France, a French Body Corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to automobile automatic clutches and more particularly to the provision of a drive between an engine, such as an internal combustion engine, and a driven shaft from which a drive is transmitted, for example to the driving wheels of a land vehicle, through a change speed gear-box. The main object of the present invention is to provide an automobile automatic clutch which will provide progressive starting and

acceleration of the driven shaft, for example of a land vehicle, whilst the clutch is of simple construction, -ear changing is facilitated and vet the braking power of the engine can be employed at opportune moments. According to the present invention an automobile automatic clutch device has an auxiliary coupling unit incorporated therein, the auxiliary unit comprising a parallel system of two branches, one branch including a uni-directional transmission device and the other branch including a torque limiting device the transmissible torque of which is predetermined to a value below the maximum engine torque, and declutching means for declutching said torque limiting device. Further in accordance with the present invention, an automobile automatic clutch is provided wherein, between the driving shaft and the driven shaft are arranged in series, on the one hand a main coupling the transmissible torque of which varies as a rising function of the speed of the driving shaft, and on the other hand, an auxiliary coupling comprising in parallel a free-wvheel locked in the forward direction, and a torque-limiting device, the characteristics of which are predetermined 50 and which is controlled by the gear lever in such manner as to be free or engaged, depending on whether the said lever is actuated or not. The main coupling is preferably chosen 55 as a centrifugal type It may be mechanical and be provided with weightheads or it may be hydraulic, such as a coupling device or torque-converter, this coupling being disengaged when the 60 engine is idling. The predetermined torque transmissible by the torque-limiter of the auxiliary coupling may be given a value slightly greater than the torque developed by the 65 compression of the engine A torque limitation of this kind, whilst enabling the engine to be used as a brake, also enables the dimensioning and the strength of the torque-limiter of the auxiliary coupling to 70 be reduced on the one hand, and on the other hand, it prevents shocks being transmitted to the transmission and skidding of the driving wheels. In one preferred form of embodiment, 75 the torque-limiter of the auxiliary coupling is provided with an electro-magnet which is connected in a eireuit comprising a switch controlled by the gear-lever This electromagnet may be arranged so as to 80 cause the application of pressure to the friction linings of the limiter device, or alternatively to annul such pressure when it is applied mechanically In the first case, means are preferably provided to 5 render the electro-magnet active only when the driven shaft tends to rotate the driving shaft, whilst the gear-lever is not actuated This enables the consumption of electric current to be substantially 90 785,395 reduced.

In all cases, the control of the auxiliary coupling by the gear-lever permits easy changing of gears in the transmission from the driven shaft In fact, at the moment of changing gears in a land vehicle, the user instinctively releases the accelerator. The driving shaft then rotates less quickly than the driven shaft; the free-wheel is thus released and the break is complete in the transmission system at the point of the free-wheel as for the torque-limiter of the auxiliary coupling. With a view to freeing the -user from the necessity of releasing, even instinctively, the accelerator at the moment of changing gear, a special control of the butterfly valve of the accelerator may be provided. This control comprises, in addition to the pedal operated by the user, a means controlled by the gear-lever and havinay a preponderance over the pedal solely in order to close the butterfly valve when the lever is actuated The primary of the ignition coil may also be mounted in a circuit controlled by the switch which is in turn controlled by the gear-lever, in order that the ignition may be cut-off at the moment of operation of the gears. In certain circumstances, for example when climbing a very steep slope with a heavily-loaded vehicle, it might be feared that any voluntary or automatic release of the accelerator and/or the cutting-off ou the ignition at the moment of changing gears, would not be sufficient to disengage the free-wheel and to permit an easy change of gears, since the driven shaft -ould slow-down more quiielylv, than the driving shaft As will be understood, this Is especially likely to occur when the main coupling is of the hydraulic type and has a parasitic or residual torque. In order to overcome this drawback, an 1 in accordance with a further special feature of the invention, the intermediate member arranged on the rear side of the wain coupling and on the forward side of the auxiliary coupling may comprise a -50 braking means on a fixed part, which is made active or inactive, depending on 7 whether the torque-limiter of the auxiliary cou 3 pling is free or engaged Even if the gears are changed as the vehicle is climb-55 ing a difficult slope, and even if the main coupling has a residual torque, the interrmediate member is powerfully braked and slows-s dow-n -er murch more rapidly than the dli- -en shaft The free-irheel is thus 60,eleased and the chan-ge of gear is carriedotit wvithout difficulty This la Li of the intermediate shaft when the gear-leer is aetuated removes the residual torque ov the mnain coupling -w h-leni the -ehiele is stationary, and permits of eas enn-agement of a gear. In order that the invention may be more clearly understood some constructions in accordance therewrith will now le described, by way

of example, with 70 reference to the accompanliing drawings, in -which Fig 1 is a viewv ini lonoituidinial crosssection of a device in accordance with the invention; 75 Fig 2 is a view on a smaller scale of a part of the said device in elevation, in the direction of the arrowrs II-II of Fig 1: Fig 3 is a diagram which illustrates the operation of the device; 80 Fig 4 is a view of a modified detail of the device of Fig 1, in lon-itudinal crosssection, taken alon_ the line IJ-IY of Fig 5; Fi g i is a correspondingo view cf this 85 detail in transverse cross-sectioni following the line V-V of Fig 4, Fi 6 is a view similar to that of Fig. 5, lint in -which the position of the members is different: 90 Fig- 7 is a diagram sholwin-g the operation of the device, comprising the arrano'ement of Figs 4 to 6: Fig S is a view similar to that of Fig. 1 lint relatino to an alternative form of ti L 95 device: Fig 9 is a view to a larger scale of a detail of Fig S in elevation flo-llowing the arrow -s IX-IN of this figure: Fig 10 is a view in longitudinal cross 100 section, also to a larper seale, of a further detail of Fig 8: Fig 11 is a diagramn Shoiri the operation of the device of Figs S to 10. In the drawinls the same reference 105 numerals are used in Figs 1-7 to designate the same or similar parts and the refererwe numerals are useds in Fies S-il to designate in those figures the same or similar parts 110 Iii the form of' emhodiajent shown in Figs 1 to 3 there can bte seeni in these figures, at 10 the shaft of the engine 11 of an autonmob-ile vehicle, and at 12 the primary shaft of the wear-hox 1 ivith 115 gear-lever 14 This '-earl-1 iox 1:3 is preferably of the s;ynchronised type. The driving shaft 10 is rigidly fixedi,,o a iy-whleel 15 which forms the wei lt Head 4 arrier of a mechanical centritu ii 120 device 16 This device constitutes a main coupling which is sensitive to the speed of the driving shaft The wveih-lt-lheias 17 are pi-oted alout spinidles 18 carried hy the ti-L-l ee 1-,, Each wveiolit head 17 is 125 pro- -i I ed v i, a friction hiunii L: 19 and 4 Ooperate 3 iitlh an, externmil cylindrical friction track fornied inside ai d Irinn 20. In additionii 3 a return spring '21 is applied to each i-eniit-lhead 17 ih order to clinin 130 785,395 ate all parasitic contact at 19, 20, when the speed of the shaft 10 is low Stop-members or abutments 22 are associated with the springs 21 so as to retain the weight-heads thus returned in suitable positions The drumn 20 is mounted so as to be fixed axially but free for rotation from the flywheel 15 It is fixed at 23 to the yoke 254 of an electromagnet, which is itself mounted on

a self-lubricating bearing 295 fixed to the plate 15 This bearing is of small diameter and surrounds the shaft 12 which is kept centred in this zone by a bearin, 26 It will be noted that the (centrifuial device is thus housed with very small space requirements, between the yoke 24 and the fly-wheel 15, inside the drum 20. The yoke 24 is rigidly fixed to the external cage 27 of a free-wheel 28, the internal ring 29 of which is fixed to the primary shaft 12 The free-wheel 28 is directed in such a way as to form a rigid coupling between the drum 20 and the shaft 12 when it is the drum 20 whien tends to drive the shaft 12, and so as to form no coupling or restraint in the contrary case With the yoke 24 is associated an armature 30 mounted fast for rotation f Iut free for lateral movement on the yoke by any suitable means, and preferably bv means of flexible tangential tongues (not shown). Two friction plates 31 and 39 are respectily fixed to the yoke 24 and to the armature '0, and are intended to grip between them a friction disc 33 which is mounted fast for rotation on the shaft 12. The plates 31, 32, the friction disc 33 and the electro-magnet 24, '30 form a torquelimitiii,, device connected in parallel with the free-wheel 28 to constitute an auxiliary coupling The assemblv comprised by the plates 31 and 32 is axially spaced apart from the electro-magnet 24, 30, and the external plate 32 carries two collector rings which are connected to the two ends of the coil 34 of the yoke One of these rings 35 receives a brush 36 connected to earth at 37 (see Fig ' whilst the other ring 3 S receives a brush 39 supplied from the battery circuit 40 of the vehiclel, through the medium of a relay 41 which cuts off or maintains the supply to the brush 39, depending on whether the gearlever 14, which operates a switch 42 in the circuit of the relay, is actuated or not. It will be noted that the circuit which comprises the primary of the ignition coil B and the switch R is controlled in dependence on the position of the relay 41. The electro-magnetie arrangement is chosen in such a way that when the coil 34 is supplied with current, the attraction between the yoke and the armature produces a gripping action on the friction disc 33 by the plates 31 and 32, which permits of a torque slightly greater than the torque developed by the compression of the engine 11, and corresponding roughly to 70 one third of the maximum engine torque. During operation, when the gear-lever 14 is not changed in position, the coil 34 is supplied with current; the friction disc 33 is gripped and is capable of transmit 75 ting a limited torque equal to the braking torque of the engine If it is the engine which is driving the vehicle, the free-wheel 28 forms a rigid coupling, since the friction-dise 33 is short-circuited, and it is 80 the action alone of

the weight-heads 17 of the centrifugal device which governs the action of the driving shaft 10 on the primary shaft 12 During starting and when accelerating, a good progression is 85 obtained, whilst when the engine has reached a suitable speed, the device rotates as a whole without slip. If it is the vehicle which tends to drive the engine, for example as a result of a 90 sharp release of the accelerator, the freewheel is inactive and the friction-disc 33. then takes part in the transmission, in series with the centrifugal device By virtue of the systematic limitation of the 95 torque transmissible at 31, 33, 32, this enables advantage to be taken of the braking torque of the engine, whilst at the same time preventing the transmission of shocks to the transmission system or the 100 skidding of the driving wheels, dangers which the centrifugal device alone could not prevent in all circumstances. When the lever 14 is disengaged into neutral in order to change gears, the coil 105 34 is no lonoer supplied with current and the friction disc 33 is totally disengaged. At the same time, the circuit of the ignition is broken The engine thus slowsdown very rapidly In addition, since the 110 driver generally releases the accelerator when changing gears, the shaft 12 tends to rotate more rapidly than the driving shaft, the free-wheel 28 is thus inactivse and all coupling is eliminated between 115 the shafts 10 and 12 The movement of the lever 14 into the neutral position thus never meets with any resistance and is carried out with great ease, as is also the engagement of the new gear, since all 120 coupling remains interrupted between the shafts 10 and 12 When changing-up through the gears, the slowing-down of the engine is always sufficient to disengage the free-wheel, in spite of the slowing-down of 125 the shaft 12, due to the engagement of a higher gear When changing-dowin through the gears, the shaft 12 accelerates at the moment of engagement of a lower gear, and the free-wheel, which is already 130 785,395 inactive, necessarily so remains after thih operation. It might, however, lie feared that wher climbing a steep slope with a heavily. loaded vehicle, the shaft 12 would have a tendenec to slow-down faster than the engine speed would fall u-hen the accelerator is released, the free-wheel being active and engagaed and preventing disengagement of the -ear It should be noted however that in these special conditio I Is in which the speed is low, the centrifugal device is not influenced by the diirum and it thus has no residual torque. on the contrary, it disengages very promptly by virtne of the springs 21.

Thus in any case, the lever can be disengaged from the neutral position On the other hand, when a lower gear is engfaged, at which the shaft 12 rotates more rapidly, such an engagement is readily carried out. In the form of embodinment shown in Figs 1 to 3, the coil 34 is constantly energised with current, except durino chanuging gear, although this current is actually only useful when the free-wheel 2 S is made inactive It is in order to avoid this waste of current during the inactive periods that certain means have been provided in the alternative form shown in Fi's 4 to 7. In accordance with these means, a switeh 43 is mounted between the collector ring 9 IS and the coil 234 (see Fig 7) The switch 43 comprises a fixed terminal 44 see Figs 4 to 6) and a movable fin-er ormed by a lever 45 The latter is pivoted so as to b)e electrically insulated from the plate 232 and is engaged in the passage 46 of a ring 47 which is fast for rotation with thie plate 32, and also in a slot 4 S formied in a ring 49 The latter is mounted with a light friction contact around the lhib of che frietion dise which is fixed for rotation -<ith the primary shaft 12. When the dr iving shaft 10 tends to witate more rapidly than the shaft 12, the lever 45 opens the switch 433 (see Fig G). The coil 34 is no longer supplied ws=;ith tirrent WV hen the primarv shaft 12 tends -o rotate more rapidly than the driving Kiaft 10 the lever 45 closes the switeh 43 see Fig: 5) and the coil:341 is then ecerised. Reference will now be made to Figs 8 11 l in which a further alternative form I embodiment is shown. There will again be seen in Fig 8, the riving shaft at 10, and at 12 the primary shaft of the synchromesh gear-box The centrifu Lgal device which flormns the main o(nplingo is in this case not mechanical but h;-dtrauhic It consists, for example, of a coupler the pump 30 of which is rigidly coupled to the shaft 10 and the turbine 51 of which is fixed to a hollow shaft 52 The Llatter is suitab)ly centred with respect to the shafts 10 and 12, anld surrounds the latter shaft 12 It hias kbeyed on to it a 70 bell-shaped member 313 which is fixed at 54 to a plate 35) The plate 55 is fixed to the outer cag-e of a free-wheel 56 the inner ring of whieh is fixed to the shaft 12. A friction-disc 57 mounted fast for rota 73 tion with the saidl shaft 12 is intended to be gripped between the plate 55 and a plate 5 8 which is mounted so as to be axially movable but fixed for rotation onl the plate 53 by means of small flexible 80 tangential tontues 59 (see Fias S and 9 The plate 3 S is applied against the frietion-disc 37 b means of the springs 60. The latter are calibrated in such 5 wvay' that the gripping'^' actioii

onl the friction 83 disc 37 by the plates 55) and 55 & permits of the transmission of a torqule which is slightlv greater thani the torque developed by the compression of the engine. The plate,8 is provided with projecting 9 Q radial limbs 61 onl whin ii are fixed triction pastilles 62 co-operatinl w:ith a fixed wrall 63 of the eashig The tastilles 62 are moved awav trom the wall 63 when the friction disc a 7 is n-RI'ipped betwveen the 93 plates 35 and madl are applied against the wrall 6:3 when the frietion-disc 5; is disenaaged The disengagement ot the firiction-dise 07 is earried out by meains oi an electro-magnet, 100 the -o e 64 of which is ri-id fixed to the bell whilst the armatun 5 is fixed to the plate 5 S The le 4 cti" ianet,4 6. the spw 60 tne olates -,, azid the frictionl-dise 57 form a torlqie-linmiter 103 device Lien is lmounited in paralle 1 with the -iree heel 36 to constitute an anxiliary coupling. The enil 66 of the yoh e 64 llas its two-, ends -oninie ted, in tle tt jel sn On at 67 110 (Fin 10 i to tvo coilector rinis 69 and 70 carid 1 tbe plate v Tile bs-es Ti and 72 ooer-te witi tie r'io-l S 69 and 70) 1 Ihe 71 sh 3 is conneeted to eartl. while the trush 72 is connreeted as, shownf 13 in Fi 11 to the 1-attery ircit 7 of thle \-ehile lb The irciiit cmprises a relay 74 similar to the relay 4 but op 1 ratinv in the -reverse direein The relay 74 mailltains oi i nttsof thle etcurrent supply of the 12 l Irusii ' 2 pedinn o wlhether the gearlev i 14 is actuated or not It will ne noted irom Fing 11 that the eircnit of the i liit tfil) (oil Bl is not afyeete(d bly tile funletionnifof' the 12 nt 5 h123 Tie eir lit 7, also eomnirises a sol-nloid i, the moring armlature 76 of w-hich is connleeted thro-lth a rod and eranlk system to the butterfly valve S of the earbirettor The control of this valve 78 130 785,395 from the pedal of the accelerator 79 is specially arranged A spring 80 tends to open the butterfly valve 78, the opening of this valve by the action of the spring being controlled by the pedal 79 by means of a rigid one-way driving device 81, in such manner that when the solenoid 75 is not energised, the butterfly valve 78 is closely controlled by means of the pedal 79, whilst when the solenoid 75 is energised, the butterfly valve 78 is closed against the action of the spring 80, whatever the position of the pedal 79 may be. The operation of this arrangement is similar to that which has been previously described, except that the consumption of current is limited to the moments when changing gear It is to be noted that the residual torque developed by the coupler 50, 51, and which may interfere with the engagement of the gears when stationary and in certain difficult circumstances, is counteracted in its effects by the braking action at 62, 63 which causes an increased and immediate

slowing-down of the shaft 52 Any type of known and/or appropriate device could also be provided, which are adapted to eliminate the effects of residual torque, for example, as known per se, by an arrangement for partly or wholly emptying the coupler when the engine is idling. It will also be appreciated that by virtue of the arrangement shown in Fig. 11, the user is freed from the necessity of releasing the accelerator when changing gear.

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* GB785396 (A)

Description: GB785396 (A) ? 1957-10-30

Improvements in and relating to mining machines

Description of GB785396 (A)

PATENT SPECIFICATION Inventor: JAMES S R Ol B'BINS 785,396 Date of Application and filing Complete Specification: Oct 3, 1955. No 28116155. Complete Specification Published: Oct 30, 1957. Index at acceptance:-Class 68 ( 1), F( 3 AX: 4 B). International Classification:-E 21 c. COMPLETE SPECIFICATION Improvements; in and relating to Mining Machines We, GOODMAN MANUFACTURING COMPANY, a Company, organised under the laws of the State of Illinois, United States of America, of H Ialsted Street and 48th Place, Chicago 9, Illinois, United States of America, do hereby declare the invention for which we pray that a patent may be granted

to us and the method by which it is to be performed to be particularly described in and by the following statement:This invention relates to mining machines of the kind which have at the front a rotary boring head having one or more radial boring arms from which cutter supports extend forwardly, each arm having such a cutter support at least at its outer end and the cutter supports at the outer ends of the arms having at their own outer ends cutters which are adapted to cut an annular kerf in the mine face when jthe machine is advanced. Such machines may have more than one boring head,, the heads being arranged side-byside on an auxiliary frame and the machine being provided also with horizontal upper and lower endless chain cutters adapted to trim the face to produce flat roof and floor surfaces. The head (heads) is (are) carried by an auxiliary frame which forms an assembly with a conveyor for removing cut material to be discharged at the back of the machine In order to provide a degree of flexibility in the boring action of such heads and in order to increase the manoeuvrability of the machine the cutter head and conveyor assembly is laterally tiltable with respect to the main body or mobile base of the machine In accordance with the invention the cutter head and conveyor assembly is provided with an adjustable three point suspension comprising a pair of supports near the front of the assembly operable to tilt the assembly about a horizontal'longitudinal axis and' a third support behind the other two pivotally connected to the assembly to permit this lateral tilting. Preferably the second support comprises a pair of substantially upright hydraulic jacks arranged on either side of the assembly, the lPrkc 3 s 6 d l upper and lower ends of ithe jacks being interconnected by common fluid lines so that the jacks are free to accommodate themselves to 50 lateral tilting of the assembly. In order that the invention may be thoroughly understood two machines in accordance with it will be described in some detail by way of example, with reference to the 55 accompanying drawings, in which: Figure 1 is a side view of a mining machine made in accordance with the present invention; Figure 2 is a plan view of the machine 60 shown in Figure 1; Figure 3 is a fragmentary detail section, taken on line Ill-III of Figure 1; Figure 4 is an enlarged fragmentary detail section taken generally on line IV-IV of 65 Figure 1; Figure 5 is a section on the line V-V of Figure 4; Figure 6 is a section on the line VI-VI of Fi'gure 5; 70 Figure 7 is an enlarged fragmentary view showing details of one form 'of adjustable three point suspension for the rear end of the cutter head and conveyor assembly of Figure 1; Figure 8 is a fragmentary section taken on 75 the line VIII-VIII of Figure 7; Figure 9 is an exploded perspective view of a second machine having a different adjustable three point suspension for the rear end

of the cutter head and conveyor assembly; and 80 Figure 10 is a diagrammatic view of the fluid, control system for the hydraulic jacks shown in Figure 9. The machine shown in Figures 1 to 8 has a mobile base frame 9, mounted on parallel 85 endless treads 10, 10 The frame '9 has a lowslung cross members '11 between the endless threads 10, 10 and forms, with the treads, an open, longitudinal trough-like space for the reception of the cutter head and conveyor 90 assembly The base frame carries the usual driving motors and controls for them. An upright auxiliary frame 13 carries a pair of forwardly projecting boring heads 14, 14 each having three radial arms 15 The boring heads 14 are fixed on parallel shafts 16 journalled in the frame 13 Each of the radial arms 15 carries forwardly projecting cutter supports 18 for cutting circular keys in the working face and rotary breaker wheels 19 for breaking down standing cores. A pair of horizontal endless chain cutter guides 20 and 21 are mounted respectively along the top and bottom edges of the frame 13 immediately behind the radial arms 15 to form guides for an endless cutter chain 22 which removes the depending and upstanding cusps left by the two boring heads 14, 14 as they are advanced into the working face. Two similar electric motors 35, 35 are mounted integrally with reduction gear casings a on main gear housings 36 which in turn, are secured to the rear of the frame 13 These motors drive the boring heads through the usual reduction and driving gears. An endless conveyor 37 is rigidly connected to the auxiliary frame 13, with which it forms an assembly which is supported for separate bodily adjustment relative to the mobile base frame 9. A pair of upright trunnion supports 38, 38 are mounted at the front end of the frame 9 and carry inwardly projecting trunnion pins 39, 39 journalled in bearings on opposite sides of the auxiliary frame 13 As shown in Figure 4, each trunnion pin 39 is mounted eccentrically on: an annular hub 41 journalled, in a needle bearing 42 on the inner side of a housing 43 forming part of one of the upright trunnion supports 38 The hub 41 is integral with a gear 44 in the housing 43, which may be rotated manually by a ratchet handle 45 through a reduction gear train consisting of a small pinion 46 on stub shaft 47, having its inner end journalled on needle bearings within the gear 44 and its hub 41 The pinion 46 is meshed with a gear 48 fixed on another shaft 49 having a smaller pinion 50 meshed with the gear 44 The ratchet handle has a shaft 45 a detachably connectable in a socket end 47 a of the stub shaft 47, so as to permit said ratchet handle to be removed from the machine when not in use. Each of the trunnion pins 39 has a partially spherical bearing sleeve

51 rotatably and slidably mounted thereon, and engaged in a correspondingly shaped bearing ring 52 fitted in the side of the frame 13 (Figure 4) so as to provide, in effect, a universal or ball joint for each of the two trunnions, thereby permitting the frame 13 to assume varying angles, and to tilt on varying axes, relative to the base frame 9 The slidable mounting of the bearing sleeves 51 on trunnion pins 39 permits limited endwise movement of said sleeves to compensate for any increase in distance betveen the trunnions and the subframe due to varying adjustments of the trunnion pins. The two trunnion pins 39, 39 are each adjustable in a circle so as to vary the position of the axis of tilting movement of the auxiliary frame 13 relative to the base frame 9, as may be required to counteract " spiralling" of the cutter head, or to make other minor 70 corrections in lateral or up-and-down steering of the machine while it is in use For instance, if the machine starts to " spiral," i e cut upwardly on one side and downwardly on the other, one side of the frame 13 may be lifted 75 and the other side lowered by moving the appropriate trunnion pin to a higher position and the other to a lower position Similarly, minor corrections in steering can be made by adjusting one of the trunnion pins to a more 80 forward position and the other to a more rearward position Smaller adjustments can be made by adjusting only one of the trunnion pins. The trunnion pins 39 can be locked in any 85 position by a spring loaded locking pin 53 (Figures 5 and 6) extending through the housing 43 to engage the teeth of one of the gears 48. Adjustment of one or both of the trunnion 90 pins 39 also permits the cutter head and conveyor assembly to tilt bodily about varying transverse axes, depending upon the relative positions of the two trunnion pins. The conveyor 37 comprises a generally U 95 shaped frame 55 supporting an endless flight type chain conveyor The conveyor frame 55 is rigidly secured to the bottom of the auxiliary frame 13, and extends back at an upwardly inclined angle, so that the chain con 100 veyor receives loose material at the mine floor immediately behind the lower cutter guide 21, and carries it for discharge The conveyor frame 55 provides a support for the rear end of the cutter head and conveyor assembly be 105 hind the trunnion pins 39, 39 A motor 56 drives the flight conveyor through a chain and sprocket drive 57 The motor 56 is also supported below the rear end of the conveyor frame and' forms a part of the cutter head and 110 conveyor assembly. The cutter head and conveyor assembly can be tilted about the axis of the trunnion pins 39, 39 by a mechanism which consists of a hand wheel 60 on a shaft 61 passing through 115 the conveyor frame 55 ' and having worms 62, 62 meshed with worm wheels 63 on shafts 64 journalled

in bearings 65, 66 along each side of the conveyor frame Each shaft 64 also carries a larger worm 67 with a worm wheel 12 C segment 68 on a bell crank lever 69 pivoted on the conveyor frame (Figures 7 and 8) The other arms 70 of the two bell cranks 69 are pivotally connected to opposite ends of a cross rod 71, free to swing beneath the conveyor 121 frame and having a ball joint 72 at its centre connected to the end of a link 73 The lower end of the link 73 is pivotally connected to a bracket 74 mounted, on the cross member 11 in the centre of the base frame 9 (Figure 5) 13 ( 785,396 afford sufficient clearance for any permissible tilting or 'lateral swinging adjustments of the cutter head and conveyor assembly as a whole.

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* GB785397 (A)

Description: GB785397 (A) ? 1957-10-30

Control valve for turbine governors

Description of GB785397 (A)

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PATENT SPECIFICATION Inventors: AKE NILS BALTZAR JARLBORG and GUNNAR EMANUEL ENSICOG 7855397 Date of Application and filing Complete Specification: Oct 8, 1955. No 28722/55. Complete Specification Published: Oct 30, 1957. Index at acceptance:-Classes 110 ( 3), H 2 D 3; and 135, P( 1 F: 9 A 4: 24 X), VE( 1 F: 4). International Classification:-F 03 b F 06 k. COMPLETE SPECIFICATION Control Valve for Turbine Governors We, AKTIEBOLAGET KARLSTADS MEKANISKA WERKSTAD, a Swedish Company, of 20, Verkstadsgatan, Karlstad, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention relates to a control valve for turbine governors, consisting of a valve housing and a control slide displaceiable therein, and forming therewith two choke spots, one for controlling the supply of pressure fluid to a hydraulic servomotor and one for controlling the outlet of fluid from said servomotor, said choke spots, being alternatingly in operation so that one of them is opened and the other closed when the control slide passes through a neutral position. According as the control slide is displaced from the neutral position, in which the two choke spots practically do not admit any liquid, the one or the other choke spot comes into play and admits liquid either in the direction to or in the direction from the servomotor, so that the servomotor piston, which may be connected to the guide vane ring of a hydraulic turbine, is displaced in one direction or the other The control slide may be connected to and set by any governing means, e.g a centrifugal governor. The object of the invention is ito make it possible to adapt a control valve of said kind to different operating conditions and to be able to vary the sensitivity of the control. According to the invention this is attained by an external adjustment member by which such an adjustability is attained that, in operation, the moment of opening of one of the choke spots is displaceable forward or backward relatively to the moment of closing of the other choke spot, i e, a variable positive or negative overlap is obtained The term " overlap " designates the distance the control slide has to

be displaced after the flow has been lPrice 3 s 6 d l cut at one choke spot until the flow is admitted, to start at the 'other choke spot In case of a positive overlap a certain range of unsensitivity is present, so' that the slide can be displaced a short distance without having any con 50 trolling effect This may be desired, for instance in such a case as when the slide is connected to a belt-driven centrifugal governor, where a belt joint effects a periodic small disturbance that should not influence the servo 55 motor adjusting the guide wheel of the turbine The meaning of a negative overlap is that the working ranges of the two choke spots overlap, so that the flow is admitted' at the one choke spot before the flow is wholly 60 cut at the other, a flow of liquid passing through the control valve all the time This has the favourable effect that disturbing reactions on, the control slide by the pressure fluid are greatly diminished 65 The invention will be described' further by way of example with reference to' the accompanying drawings, in which Fig, 1 and Fig. 2 are sectional views of two different embodimnents of the control valve according to the 70 invention. In Fig 1, numeral'11 designates a servomotor cylinder, in which a piston 13 is displaceable Said piston is connected to and serves for setting the guide ring of a hydrau 75 lic turbine, A passage 15 connects the cylinder to the control valve shown at the left side of the figure 'Said valve controls the communication of said passage 15 with a pressure oil supply passage 17 as well as with an outlet 80 passage 19 The control valve consists of a valve housing 21 having a cylindrical bore, and a control slide 23, 25 displaceable therein The slide is connected to and is set:by a centrifugal governor (not shown) driven by the & 5 turibine, The control slide is composed of two members, viz a lower solid member 231 which wholly fills up the cylindrical bore of the valve housing and which is integral with an upwardly extending rod 217 of a smaller dia 90 meter, and an upper sleeve-shaped member which also wholly fills up the bore of valve housing and which is slipped upon the rod 27 and connected thereto by threads 29. The members 25 and; 27 are locked' relatively to each other by a lock nut 30 integral with a handle 31 An index 32 attached to the rod 27 cooperates with a graduated scale 34 on the slide member 25 and serves to show the relative position of the members 23, 25. Turned out in the cylindrical bore of the valve housing are three circumferentially extending recesses 33, 35 and 37 connected respectively to the pressure oil supply passage 17, to the passage 15 leading to the servomotor cylinder, and to the outlet passage 19 The upper edge of the recess 33 and the step of the slide member 23, where the same merges; with the rod 27, form, together a control or choke

spot, by means of which the communication between the passages 17 and 15 is controlled In the shown neutral position of the control slide the communication is barely closed When the slide is displaced downwardly from said position the communication is gradually opened, so that pressure oil can flow to the servomotor cylinder The lower edge of the recess 37 and the lower end of the slide member 25 form together a second control or choke spot controlling the communication between the passages 15 and 19 In the shown neutral position of the control slide also said communication is barely closed, and when displacing the same upwards the communication is gradually opened so that oil in the servomotor cylinder can escape through the passages 15 and 19 and the piston is allowed to move upwards. 4 When it is desired to make the turbine control more insensitive, the lock nut 30 is loosened and the slide member 25 is screwed down on the rod 27, so that the choking edges of the two slide members are brought closer together, an overlap being reached whereby, after one of the choking spots has closed its flow path, the control slide has to be displaced a certain distance before the other choke spot opens its flow path When it is desired instead to have a negative overlap or what is also called overflow," the two slide members are screwed farther away from each other, so that in certain positions around the neutral position the abovementioned two flow paths are open simultaneously The suitable magnitude of the overlap or overflow can easily be tried out during operation of the turbine plant and can be adapted to its varying working conditions. In the control valve shown in Fig 2 the control slide is made of one part, but instead the valve housing is provided with a divided lining in order to make possible an adjustment of the overlap or overflow, while the plant is in operation For the rest the design is similar to that of Fig 1, and corresponding details bear the same designations in the two figures. Inserted in the bore of the valve housing having the turned-out recesses 33, 35, 37 is a 70 lining which consists of an upper part 39 secured against turning and a turnable lower part 41, said parts being connected to each other by threads 43 Threaded onto the lower end of the lower lining part 41 is a nut 44 75 locked in a fixed position thereto and a nut 45, by means of which the part 41 is fastened in its adjusted position The lining has a cylindrical bore in which the control slide 46 is displaceable Cut out in the inner surface 80 of the upper part 39 of the lining is a recess 4.7 which by means of holes 49 distributed all around communicates with the recess 37. The lower part 41 of the lining has a corresponding recess 51 which by means of holes 85 53 distributed all around communicates with the recess 33 The control slide 46 has a part turned to a smaller

diameter, around which an annular space is left between the slide and the valve lining Said space communicates 90 with the recess 35 by means of holes 57 through the lining, distributed all around. Where the full-sized slide part meets the turned-down part 55 there are formed choking edges 59, 61 which cooperate 'with the 95 lower edge of the recess 47 and with the upper edge of the recess 51, respectively, so as to form therewith two choke spots, one for controlling the communication between the passages; 15 and 19 and one for controlling 100 the communication between the passages 17 and 15 The choking edges, 59, 61 are the outer edges of a number of bevel cuts at the end of the full-sized, part of the slide The adjustment nut 44 has a graduated scale 63 readable 105 against a fixed index 65. When it is desired to change the overlap, the nut 45 is loosened and the adjustment nut 44 is turned in one or the other direction, so that the two parts 39, 41 of the valve 110 housing are moved towards or away from each other, whereupon the part 41 is again fastened by the nut 45 Said adjustment can easily be made while the turbine is running and without disturbing its control The set 115 positive or negative overlap can be read on the scale 63, and consequently it is possible to accurately set the positions that by previous experience have been found suitable for the different operating conditions 120

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