4826 4830.output

* GB785233 (A)

Description: GB785233 (A) ? 1957-10-23

Improvements in or relating to cathode-ray tubes for reproducing images

Description of GB785233 (A)

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BE536169 (A) CH328926 (A) DE971669 (C) FR1120039 (A) BE536169 (A) CH328926 (A) DE971669 (C) FR1120039 (A) less Translate this text into Tooltip

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I SsAlly, Ill t? 4' 1 LIo fr R sty 1 poet PATENT SPECIFICATION Date of Application and Filing Complete Specification: Mar 1, 1955. Application mode in Netherlands on Mar 4, 1954. Complete Specification Published: Oct 23, i 957. E Rl A Tr JI 4 SPECIFICATION NO 785,233 , line 1, for "Phillips" read o Philipsel. THE PATENT OFFICE, o 5th November, 19 'f 7 ana oy tne rollowing statement:- This invention relates to cathode ray tubes each having three electron guns for reproducing images, and to apparatus embodying such tubes. Tubes with three parallel guns are known both for use in oscillography and for reproducing television images in colour In the latter case the three beams converge to one point on a target, which may be a luminescent screen or a grid of parallel wires arranged in front of

such a screen In the following description the word "target" denotes either a luminescent screen or a perforated electrode, such as a grid, arranged in front of a luminescent screen In the first mentioned case the three beams must be directed to the same point on the luminescent screen, whereas in the other case it is more usual to direct them towards the same point on the perforated electrode. In colour television tubes with three guns it is necessary for the three electron beams to be directed at any instant towards the same point of the target, even when they are deflected during scanning This could be effected by associating each beam with an individual deflecting system, but it would then be necessary to use deflecting voltages of a special form These voltages would have to be highly asymmetrical for the scanning to be symmetrical. It has been proposed to associate each gun with deviating means individual to it for adjusting the direction of the corresponding beam so as to ensure that the three beams shall intersect as required We have found, however, that satisfactory results can DB 00840/1 ( 8)/3606 150 11/57 R three substantially coplanar electron beams for scanning a target under the control of two deflecting fields which are common to Si all three said beams and are substantially perpendicular to one another, characterized in that two of the said guns are associated with deviating systems which are individual thereto, which are located between the said 60 guns and the said deflecting fields, and which are adapted for ensuring that during scanning the corresponding two beams shall intersect the third beam at incidence on the target; and further characterized in that the 65 third gun is not associated with a deviating system individual thereto. The term "deflection" in this description means the common deflection of the three beams for effecting scanning The term 70 "deviation" means the deviations imposed on two of the beams to give them the correct direction before they enter the common deflecting field. The invention has the advantage that the 75 deflecting system can be energized with voltages or currents of the usual form, for example the saw-tooth form Owing to the three electron beams, upon entering the deflection field, being located in one plane, 80 the advantage is obtained that if the beams intersect at one point for a particular intensity of the deflecting field, they will always intersect in this way (apart from the error known as "coma") when the deflection is 85 varied When the three beams are regarded as parts of one composite beam, it can thus be said that no interfering astigmatism occurs However, one error still remains, viz. that the surface which is the locus of the 90 (Price 3 Jo m= Time 785,233 No 6026155. PATENT SPECIFICATION

Date of Application and Filing Complete Specification: Mar 1, 1955. 785,233 No 6026/55. Application made in Netherlands on Mar 4, 1954. Complete Specification Published: Oct 23, 1957. Index at Acceptance:-Class 39 ( 1), D 4 (A 4: A 7: Dl: E 3 A: E 8: K 4: K 7: K 8), DIO(A 2: B 2). International Classification:-H Olj. COMPLETE SPECIFICATION Improvements in or relating to Cathode-ray Tubes for Reproducing Images. We, PHILLIPS ELECTRICAL INDUSTRIES LIMITED, of Spencer House, South Place, Finsbury, London, E C 2, a British Company, 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 cathode ray tubes each having three electron guns for reproducing images, and to apparatus embodying such tubes. Tubes with three parallel guns are known both for use in oscillography and for reproducing television images in colour In the latter case the three beams converge to one point on a target, which may be a luminescent screen or a grid of parallel wires arranged in front of such a screen In the following description the word "target" denotes either a luminescent screen or a perforated electrode, such as a grid, arranged in front of a luminescent screen In the first mentioned case the three beams must be directed to the same point on the luminescent screen, whereas in the other case it is more usual to direct them towards the same point on the perforated electrode. In colour television tubes with three guns it is necessary for the three electron beams to be directed at any instant towards the same point of the target, even when they are deflected during scanning This could be effected by associating each beam with an individual deflecting system, but it would then be necessary to use deflecting voltages of a special form These voltages would have to be highly asymmetrical for the scanning to be symmetrical. It has been proposed to associate each gun with deviating means individual to it for adjusting the direction of the corresponding beam so as to ensure that the three beams shall intersect as required We have found, however, that satisfactory results can be obtained by using the direction of one beam, preferably the centre beam, as a standard and providing each of the other two beams with deviating means for adjusting their direction in relation to this standard 50 The invention comprises a cathode ray tube in which three electron guns produce three substantially coplanar electron beams for scanning a target under the control of two deflecting fields which are common

to 55 all three said beams and are substantially perpendicular to one another, characterized in that two of the said guns are associated with deviating systems which are individual thereto, which are located between the said 60 guns and the said deflecting fields, and which are adapted for ensuring that during scanning the corresponding two beams shall intersect the third beam at incidence on the target; and further characterized in that the 65 third gun is not associated with a deviating system individual thereto. The term "deflection" in this description means the common deflection of the three beams for effecting scanning The term 70 "deviation" means the deviations imposed on two of the beams to give them the correct direction before they enter the common deflecting field. The invention has the advantage that the 75 deflecting system can be energized with voltages or currents of the usual form, for example the saw-tooth form Owing to the. three electron beams, upon entering the deflection field, being located in one plane, 80 the advantage is obtained that if the beams intersect at one point for a particular intensity of the deflecting field, they will always intersect in this way (apart from the error known as "coma") when the deflection is 85 varied When the three beams are regarded as parts of one composite beam, it can thus be said that no interfering astigmatism occurs However, one error still remains, viz. that the surface which is the locus of the 90 (Price 3 g_ 2 A go 785,233 intersection of the three beams is not flat. This is a disadvantage, since the target can usually be regarded as a flat surface to a first approximation. Since two of the electron guns are associated with individual deviating systems, it can first be ensured that the beams shall meet at one point on the target for a particular strength of the deflecting field and then the necesary correcting voltages can be applied to the above mentioned deviating systems so that the curved locus of intersections shall be deformed into coincidence with the target. If the three electron guns are inclined to one another so that their axes meet at one point on the target, it is only necessary to apply simple correcting voltages to the deviating systems to ensure that the beams shall still intersect on the target when the deflecting field is operative. In this case it is immaterial which two of the three electron guns are provided with deviating plates, since the direction of one electron beam can always be regarded as the standard direction, so that the other beams can be directed towards the point at which the first mentioned beam strikes the target. This arrangement has, however, the disadvantage that the space

occupied by the electron -guns is larger than the space required if the axes of the guns are parallel. It is thus frequently more advantageous to arrange the three guns with their axes parallel and to ensure by applying suitable direct voltages to the deflecting or deviatina svstems that the three beams shall meet at a point on the target when the deflecting field is not operative. If the axes of the three guns are parallel it is advantageous to associate the deviating plates with the outer guns, and to direct the central gun towards the centre of the target. The whole structure of the electrode system is thus rendered symmetrical and hence relatively simple. Since the electron beams are located in a plane, they need be deviated in this plane only If there should be small errors diverting the beams away from this plane before they reach the deviating electrodes the beams can be brought back into the plane by effecting a correction by means of magnets located outside the tube As before, the direction of one of the beams can be taken as the standard direction, the other two beams being deflected magnetically so that all three beams come to lie in one plane. Preferably the two outer beams are adjusted by magnetic means in this way However. in this case it is necessary for the central beam to be magnetically screened The screen may consist, for example of a ferromagnetic envelope surrounding at least part of the central gun Alternatively, one electrode of the central gun could be made of ferromagnetic material. In order that the invention may be readily carried into effect, an emnbodiment will now 70 be described by way of example with reference to the accompanying drawing mn which a cathode ray tube is shown diagrammatically and partly in section. The cathode ray tube shown in the draw 75 ing has a cvlindrical neck 1 and an adioining conical portion 2 closed by a slihtly curved window 3 The latter is cosered on its inner side with a luminescent layer 4. Inside the neck I are three straight parallel 80 electron guns whose axes are located N one plane The three guns are identically similar execept for the deviating plates of the two outer guns The left hand gun for instance. has a cathode 5 control grid 6 accelerating 83 anode 7 and main anode 8 This portion of the gun produces a stream of electrons which is already slightly beamed but must be concentrated still further in order that it may have a verv smnall cross-section at the target 90 The concentration is effected by means of electrodes 9 and 10 -which, torether with the anode 2 or nsitte a lens svste To For this pur:po- f t of course, necessary to apply suita'i:-otam to the electrodes 5 to

1095 inclusive Howec-r these arrangercsnts do not characterize the invention the gun belar constructed and connected into circuit in known manner M Aternativelv a triode svstem, for e-amei without an accelerating 100 anode could be used. Each of the two outer runs, but not the middle eun is furnished with a pair 11 o)r 12 of deviating plates The Figure shows a set of coils 13 14 for scanning in one 105 direction A similar set of coils for scannina in a direction at right angles to the first direction has been omitted from the drawing for the sake of clarity By applying suitable direct voltages to the deviating systems 110 11, 12 the three electron beams can be made to meet at one point 15 at the centre of the luminescent screen 4 when the deflecting coils are not energized, and after having been adjusted in this way the three beams 113 always intersect substantially in one point. even when deflecting currents are supolied to the deflecting coils However in order to ensure that the noint of intersection shall always be located on the luminescent screen 120 4 it may be necessary for the deviating svstems 11, 12 to be supplied, in addition with correcting voltages, which are derived from the voltages driving the currents in the deflecting coils As an alternative, the lurni 125 nescent screen 4 may be curved in such a way that the three beams always intersect on the luminescent screen withlout the use of correcting voltages In this case only fixed direct voltages need be applied to the 130 785,233 deviating systems 11, 12 Another possibility is to use deflecting coils of a particular shape, as has been explained in a prior patent application not published at the date of this application.

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* GB785234 (A)

Description: GB785234 (A) ? 1957-10-23

Improvements in pit props


PATENT SPECIFICATION 785,234 Date of Application and Filing Complete Specification: Mar 4, i 955. Application made in Germany on March 22, 1954. Applicotion made in Germany on April 15, 1954. Application made in Germany on April 20, 1954. Application made in Germany on May 8, 1954. Application made in Germany on August 9, 1954. Application made in Germany on January 10, 1955. Complete Specification Published: Oct 23, 1957. Index at Acceptance-Class 202), E 2 D 3 (A:C). International Classification:-E 23 d. COMPLETE SPECIFICATION. Improvements in Pit Props. 1, HANS GERLACH, of Homberger Strasse 86, Moers/Niederrhein, Germany, a German citizen, 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 telescopic pit props of the kind comprising an inner and an outer prop member, movable one relatively to the other, and a prop lock secured to one of said prop members The member to which the lock is secured will hereinafter be referred to as the first prop member and the other as the second prop member. Pit props of the above kind, and in which a steel inner prop is clamped by steel clamping faces, have the disadvantage that the two parts move relatively to one another in a spasmodic manner and this movement produces explosive noises, due to the difference between the coefficients of friction when the parts are moving and are at rest This behaviour of a pit prop may, moreover, sometimes have a disadvantageous effect on the roof which it supports, and remedies have therefore been sought. Friction faces of light metal alloys based on aluminium have been found to give a considerable improvement and, in general, pit props having such friction faces move uniformly and without noise However, many sections of the mining industry are of the opinion that, when used as friction faces on steel, aluminium alloys may under certain conditions produce sparks which may ignite fire-damp, and they therefore refuse to use them. It is an object of this invention to over(Price 3/6) come the above

disadvantages to which end it provides a pit prop of the kind set forth, wherein the surface or surfaces of the part or parts engaging the second prop member is or are of steel and provided with at least 45 one insert of a material which is different from that of the friction surface of the parent body carrying this insert, and the area of the insert contacting the second prop member is smaller than that of said friction sur 50 face of the parent body, for the purpose indicated herein. Thus, in using a pit prop according to this invention, the slight but ever present wear on the surface carrying the insert or inserts 55 forces small particles of the material thereof, as a kind of lubricant, between the main clamping faces to equalize the static and dynamic coefficients of friction, as a result the explosive noise disappears and the load 60 absorption becomes uniform. The insert, or each of them, may be of various shapes and forms, e g of strip form. Moreover the insert can be applied and secured to the parent body in various ways 65 For example it may be mounted -in an appropriately shaped groove or recess in this body and held by co-operation of its edges with that of the groove or recess To this end, the co-operating edges may be rough 70 ened. Again, the or each insert may be applied to the steel parent body by welding, e g as -a welding bead or strip deposited in a groove produced -by a chip-removing treat 75 ment or by chip-free shaping; such welding beads, which are conveniently of non-ferrous metals, interrupt the steel contact surfaces and possess the properties desired according to this invention 80 No 6484155. 2 785,234 The welding may be effected in an atmosphere of a protecting gas, so that it is possible to carry out the application of these welding beads with the aid of automatic welding machines which work up a blank welding wire from a roll and form the bead directly in the welding position During the welding operation, the edge zones of the parent body and insert may be hardened. and this hardening can be controlled as desired by preheating the parent body to any particular desired temperature before the welding. In all cases, it may be advantageous to allow the insert which has been applied to the parent body in one way or another to project slightly from the surface of the latter, but embodiments of the invention are also possible in which the surface of the insert lies initially flush with the contact surface of this parent body. It has been found to be especially suitable for the purposes of the invention to use alloys of copper with silicon and manganese as the inserts, an alloy of copper containing, by weight, 3 5 ', of silicon and about 1 % of manganese having been found to be particularly

advantageous. Further features of the invention will be apparent from the following description of the accompanying drawings, in which: Figs 1, 2 and 3 show, in longitudinal section three embodinments of a pit prop according to the invention: and Fig 4 shows, on an enlarged scale a portion of a contact surface in accordance with the invention. In the embodiments illustrated in Fiqs I and 2, an inner prop member I (which conveniently tapers slightly) is held against an outer nro D member 2 by clamping in a proplock 3 which is welded to the outer member 2 Thus the outer pron member 2 is the "first prop member" and the inner member 1 the "second pron member" The clampine is effected with the aid of one or more horizontal wedges 4 but alternatively, in nlace of such wedges, other tightening elements, for example screws, eccentrics or the like, may be employed In the embodiments Ohown in Figs 1 and 2 the tightening wedges 4 which are used in setting up and removing the pron act on a spacer 5 disposed in the pron lock. Tn the embodiment illustrated;n Fa 1. the mnaer 5 and the hack wall of the bodv of the lock 3 (which bears diretyiv aiainst the inner nroo member 1) provide the S 5 urfaces which clamn) against the inner pron member The surface of the spacer 5 and the rear wall of the lock 3 which contact this inner nrop member are interrupted at the top nnd approximately midwnv alono their lennths by inserts or strins 6 and 7 which are made of a material different from that of the parent body These inserts or strips are arranged transversely to the direction of relative movement of the prop member. The arrangement of the strips 6 and 7 is such that, when the inner prop member 70 sinks into the outer prop member, the material is abraded therefrom and is smeared into the contact surfaces of the spacer 5 and the rear wall of the lock to apply a lubricating medium in the main pressure 75 zones of the wedges 4 In the case of clamping mechanisms using only one wedge and a shorter lock, one strip at the top edge of each contact surface is sufficient. The spacer 5 may be made in two parts, 80 such that a separate spacer part is associated with each tightening wedge 4, and in this case the two parts of the spacer should each carry at least one strip 7. In the case of the pit prop shown in Fig 85 2, a tow wedge 8 of known operation and forming part of the prop lock is arranged between the spacer 5 and the inner prop member l In this case the tow wedge and not the spacer, is provided with strips 7 in 90 accordance with the invention In fact, three strips are shown on each of the two contact surfaces to indicate that, in the case of long clamping faces, a larger number of strips may be of advantage 95 When the strips 7 are first mounted in position they may be made to project from the base

material, i e steel, a few tenths of a millimetre in order that, on the first movement of the inner prop, smearing of the 100 contact surfaces with the material of the strips and flattening of the strips will take place. Instead of being in the form of strips the inserts of the softer material which are to 105 provide a lubricating medium may be arranged in cup-like depressions distributed over the contact surfaces, but in any event are of smaller area than the friction surface of the parent body 110 Figs 3 and 4 show an embodiment of the invention in which the prop members l and 2 are held clamped together by a single horizontal wedge 6 and a second spacer 12 is interposed between the rear wall of the prop 115 lock in a depression in this wall The inserts 7 are here arranged on the spacer 5 and on the spacer 12. Moreover, in this case the inserts 7 are in the form of welding beads which are de 120 posited, in the presence of a protecting gas. on the spacers 5 and 12 These welding beads, as shown in Fig 4, may be deposited in trough-like grooves 13 which are arranged transversely of the length of the inner prop 125 member 1 and may project by a small amount from the surface of the spacers 5 and 12. In all cases the strips 7, regardless of whether they are in the form of inserted 110 785,234 785,234 3 strips or welding beads, are preferably made of copper or copper alloys, preferably alloys containing silicon and manganese, for example with a silicon content of 3 5 % and a manganese content of about 1 % When the strips are in the form of welding beads, the parent body (e g the parts 5 or 12) may advantageously be preheated to keep the hardening of the strips within certain desired limits during the welding operaton. It is also possible, in many instances, to apply the material, when one of the range of alloys hereinbefore indicated is employed, to the contact surfaces by extrusion. The proposals forming the basis of my invention may be applied not only to pit props but also to other yielding roof supports used in mines, and the term "pit prop" should be read as including such parts.


* GB785235 (A)

Description: GB785235 (A) ? 1957-10-23

Improvements relating to contact assemblies for electric circuit breakers


We, METROPOLITAXT-VI Cei ERS ELECTRICAL COMPANY LIMITED, a British Company, having its registered office at St Paul's Corner, 1-3 St Paul's Churchyard, London, E C 4, 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 contact assemblies for electric circuit breakers and is concerned with providing a contact assembly which in conjunction with a moving contact assembly actuated by the operating mechanism of the breaker will provide an enhanced overall length of break in a controlled circuit for a given travel of the moving assembly. To ensure that a circuit breaker will effect satisfactory interruption of a high voltage circuit it is necessary for the breaker to introduce a minimum overall length of break into the circuit In oil circuit breakers the length of travel required by the moving contact assembly to produce the required break largely determines the necessary depth of the oil tank and the volume of oil required, and as the voltages with which such breakers have to deal have increased it has become increasingly important to reduce the travel required for a given break length in order that manufacturing and erecting costs shall not be unduly inflated by the size of oil tank and quantity of oil required. In the simplest form of oil circuit breaker in which a single "fixed" contact, which may be mounted with a degree of resiliency, co-operates with a moving contact provided in an assembly actuated by the circuit breaker operating mechanism, the length of break provided generally corresponds to the travel of the moving contact assembly, lPrice 3 s 6 d l taking into account any resilient movement (which will be relatively small) of which the fixed or moving contact may be capable. This length of break can be doubled for the same travel of the moving contact assembly by providing two such fixed contacts and arranging the moving assembly to bridge these contacts electrically in the

closed position of the circuit breaker, thus providing for two breaks in series when the breaker is open, namely one between each fixed contact and the " bridge ". It has previously been proposed to enhance the length of break provided by either of the above arrangements for a given travel of the moving contact assembly by replacing the or each fixed contact by a contact assembly including a contact which, on closure of the circuit breaker, is actuated by an insulating member on the moving assembly towards a co-operating contact in this latter assembly, the combined movement of the two contacts towards each other being effective to reduce the length of travel required by the moving contact assembly in order to close the break provided between these contacts when the interrupter is open; conversely, the arrangement is effective to increase the length of break that can be obtained for a given travel. According to the invention there is provided in or for an electric circuit breaker a contact assembly providing for two breaks in series and including three contacts of which the first is in permanent electrical connection with one of the others and is adapted for engagement by a contact of a moving assembly actuated by the operating mechanism of the breaker, while a second is movable into and out of engagement with the third and is arranged to be moved at least into such engagement by means of an 785,235 PATENT SPECFICATION Inventors:-CEDRIC HAROLD FLURSCHE Iil M and HARRY HOLUES. Date of filing Comsbplete Specification: Mltaroh 9, 1956. Application Date: Maarch 11, 1955 No 7265155. Complete Specification Published: Oct 23, 1957. Index at Acceptance:-Class 38 ( 5), B 1 X 1 A( 3: 5: 6), B( 2 C 6 F: 40). International Classification:-HO 2 c. COMPLETE -SPECIFICATION. Improvements relating to Contact Assemblies for Electric Circuit Breakers. 785,235 insulating member movable with said moving assembly, the contacts being so positioned in relation to each other as to define respective arc paths extending in the same direction as that in which an associated moving assembly will move but lying on opposite sides of a line parallel to that direction and overlapping each other as viewed in a plane including said line, and the contact arrangement being such that on opening the circuit breaker the two breaks will be effected substantially simultaneously. The contact assembly of the invention accordingly provides for a total length of break equal to the sum of the two individual breaks, and as the break between the first contact of the assembly and the co-operating contact of an associated moving assembly can correspond

substantially to the travel of the 2 o latter, the total break introduced for a given travel of the moving assembly is thus enhanced to an extent equal to the distance by which the second and third contacts will be separated in the open position of the circuit breaker. The three contacts of the contact assembly preferably consist of a "fixed " contact corresponding to the third contact referred to, which contact may be mounted with a degree of resiliency, together with two further electrically interconnected contacts one of which is arranged for engagement by the contact of the moving assembly and the other of which is movable by the insulating member into and out of engagement with the fixed (third) contact, which latter contact may be arranged for connection to a terminal of the circuit breaker, for instance to a bushing conductor by which said contact assembly as a whole is supported and from which the other two contacts of the assembly are insulated in the open position of the circuit breaker The second contact referred to may be arranged for movement by the 4 ea insulating member on the moving assembly only into engagement with the third, preferably fixed contact, this movement being effected against a spring action which during subsequent opening of the circuit breaker is effective to urge the second contact out of engagement with the third Furthermore the second contact may be pivotally mounted for its movement into and out of engagement with the third contact, in which case it may conveniently be carried or constituted by a conductive member pivoted on a mounting member which is also conductive and in turn carries or constitutes the first contact for the assembly, the first and second contacts thus being in electrical connection; alternatively the second contact may be carried or constituted by a pivoted conductive member which itself also carries or constitutes the first contact at a position near its pivot In either case it may be arranged that the first contact of the assembly is resiliently mounted so as to make resilient engagement with the co-operating contact of an associated moving assembly. Oil and other liquid-immersed circuit 70 breakers are commonly provided about their co-operating contacts (at least in the engaged positions thereof) with arc-controlling shrouds which define arcing chambers for receiving arcs incidental to separation of the contacts 75 on load and serve to control the arc and /or movement of the oil or other liquid with the intent that the arcs will be broken and the arc path de-ionised as soon as possible after the contact separation has been effected SO Several forms of are-controlling shroud are known, including the so-called cross-jet explosion pots which are formed with exhaust ports leading from the arcing chamber at positions to the side of the arc 85 path defined between co-operating contacts, with the

result that when an arc is drama the pressure consequently generated in the chamber tends to expel the arc products forcibly through the exhaust ports and 90 thereby create a flow of oil (or other liquid) transversely of the arc path, which is thus cleared of ionised matter in a relatively short time. In carrying out the invention for oil or 95 other liquid-immersed circuit breakers contacts of the assembly provided thereby are preferably arranged in the arcing chamber of an arc-controlling shroud having sets of exhaust passages leading from the arcing 100 chamber at positions disposed to the sides of the respective arc paths which will be defined therein namely between the second and third contacts of the assembly and between the first contact and the co-operating 105 contact of an associated moving assembly. The contact assembly of the invention may then be arranged for use in conjunction with a moving assembly including, in position extending parallel to the direction of move 110 ment thereof, an elongated contact member for engaging the first contact of the said contact assembly and an elongated insulating member for actuating the second contact of the contact assembly, the arc-controlling 115 shroud being suitably apertured to receive these elongated members (when the circuit breaker is closed) in position extending into the shroud and respectively making engagement with said first contact and causing 120 engagement between the second and third contacts. It has been stated above that the travel required by the moving assembly of an oil circuit breaker largely determines the depth 125 a of oil tank required When a shrouded contact assembly in accordance with the invention is employed in conjuction with such moving assembly the tank depth will also be influenced by the dimension which the 13 P) applicable to an oil circuit breaker will now be described with reference to the accompanying drawing in which the somewhat schematic single Figure illustrates a shrouded contact assembly in accordance with the 70 invention together with one end of a cooperating horizontal bridging conductor which is assumed to co-operate at its other end with a similar contact assembly (thereby providing for interconnection of the two 75 assemblies in series) and forms part of a moving assembly actuable by the circuit breaker operating mechanism, not shown, so as to move the bridging conductor in a vertical direction, that is transversely of its 84} length. Referring to the drawing, each terminal of the circuit breaker is provided in the usual manner by a conductor 1 extending through the top of the oil tank (not shown) by way of 85 an insulating bushing 2 At the lower end of the bushing 2 there is mounted on a metallic support member 3 which is electrically integrated with the conductor 1, a hollow structure 4 of insulating material 90 defining an

arc-controlling shroud for the contact assembly as will be more fully described hereinafter This insulating shroud 4, which is shown in cross-section in the drawing, is preferably constituted by a stack 95 of suitably shaped insulating plates bolted or otherwise secured together. Within the arcing chamber 5 of the insulating shroud 4 are secured two parallel plates 6 (only one being seen in the drawing) each 100 having a vertical slot 7 A transverse pin 8 secured fast with a metallic contact arm 9 adjacent one end of the latter, rides in the slots 7 and when in engagement with either end of the slots forms a pivot for the arm 105 At the pivot end of the arm 9 a portion 10 of increased thickness defines a first contact surface 101 against which abuts, in the closed position of the circuit breaker as shown, the end of a plunger or poker contact 110 11 extending vertically upwardly from the bridging conductor 12 of the moving assembly of the breaker At the other end of the arm 9 another portion of increased thickness defines a second contact surface 131 which in 115 the closed position of the breaker engages a " fixed " contact 14 resiliently mounted by means of a spring 141 in a downward extension 31 of the support member 3. In the bottom of the insulating shroud 4 an 120 aperture 15 permits the poker contact 11 to enter the arcing chamber 5 and engage the contact surface 101, while another aperture 16 permits an insulating rod 17 extending from the bridging conductor 12 parallel to the j 25 poker contact 11, to enter the arcing chamber and engage the underside of the contact portion 13 of the arm 9. Starting from the closed position shown, on opening the circuit breaker, a spring (not 130 shrouds require to have in the direction of movement of the moving assembly in order that arcing across the breaks provided for, in particular thats between the co-operating contacts of the two assemblies, will take place substantially within the shroud Hovwever with an arrangement according to the invention, the minimum dimension required by the assembly in the direction in question for a given total length of break can be reduced by an amount corresponding to the extent of such overlapping of the arc paths, as compared with the dimension which would be required in the absence of any overlapping Furthermore where an associated moving contact assembly has an elongated contact member which is to project into the shroud to engage the first contact of the contact assembly therein, the necessary length of this elongated contact member can be reduced by a corresponding amount. A circuit breaker may include two contact assemblies in accordance with the invention associated with a moving assembly including two contacts arranged for respective cooperation with the first contacts of said contact assemblies and electrically interconnected by a

bridging conductor so that the breaks provided for by the two contact assemblies in conjunction with the contacts of the moving assembly are in series. The exhaust passages of the arc-controlling shroud within which the contact assembly of the invention may be contained, may pass directly through the walls of the shroud at appropriate positions therein With the contact assembly arranged so that the arc paths which will be defined across the breaks provided for overlap in the manner previously mentioned, the setfs of exhaust passages of a containing shroud will preferably be arranged to lead from the arcing chamber of the shroud at positions at the opposite sides of the chamber adjacent which the arc paths lie It may then be that if the exhaust passages passed directly through the walls of the shroud an exhaust from the shroud would, in the assembled breaker, be directed towards a relatively closely adjacent W O tank wall or, if the breaker included two such shrouded contact assemblies as previously indicated, towards an exhaust from the other shroud As this might lead to dangerous concentrations of ionised gases on opening o 5 of the breaker on load, it is contemplated that the exhaust passages of one or both sets thereof may be so formed in the wall of the shroud as after leading from the arcing chamber in the direction transversely of the appertaining arc path, to change direction and open to the exterior of the shroud in a suitable direction transverse to the initial direction. In order that the invention may be more t J 5 fully understood an embodiment thereof 785,935 7835, 235 shown) which was compressed on closure will in the usual manner cause the mroving assembly including the bridging conductor 12 to move rapidly downwards into a fully open position in which the poker contact 11 and the insulating rod 17 are withdrawn from the shroud 4 and the contact arm 9 is urged downvardly by a compression spring 18 into a position, indicated in chain dotted lines, in which a stop 19 defined on the arm engages an internal surface 20 of the shroud 4 and the pivot pin 8 engages the bottom ends of the slots 7 During a short initial fraction of the downward movement of the arm 9 into this position, the movement being a pivotal one about the pin 8 after the latter has reached the bottom of the slots 7, she pivot end of the arm 9 follows the poker contact 11 owing to the movement of the pin 8 in the slots 7, and the contact 14 follows the other end of the arm 9 under the action of the spring 141 Thereafter continued downward movement of the poker contact 11 and of the rod 17 followed by the arm 9 results in the contact surface 131 disengaging from the contact 14 substantially at the same time as the pokef contact 11 disengages from the contact surface 101. On reelosing the circuit breaker the poker contact 11 and the

insulating rod 17 again enter the arcing shroud 4 by way of the apertures 15 and 16 The insulating rod 17 first engages the contact arm 9 to urge it upwardly about its pivot pin 8 against the action of the spring 18, thereby moving the contact surface 131 towards the contact 14. The relative lengths of the poker contact 11 and the rod 17 are so chosen that at the same time as the contact arm 9 reaches the position at which the surface 131 engages the contact 14, so also does the poker contact 11 come into engagement with the contact surface 101. Continued movement to the fully closed position then compresses the spring 141 of the contact 14 and further compresses the spring 18 to move the pivot end of the arm 9 upwardly until the pin 8 reaches the top of the slots 7, it being appreciated that in this way resilient engagement with contact pressure determined by the strength of the springs 141 and 18 is effected both between the contact surface 131 and the contact 14. and between the contact surface 101 and the poker contact 11. With the breaker thus closed a circuit is completed from the terminal provided by the conductor 1 through the contact 14, the contact arm 9 and the poker contact 11 to the bridging conductor 12, hlience the circuit is continued in a similar (but reverse) manner through the other, similar contact assembly with which the bridging conductor 12 co-operates and thence to the other terminal (for the same pole) of the breaker. d 5 When on opening the circuit breaker the moving assembly including the bridging conductor 12 has reached the fully open position, four breaks wvill have been introduced in the circuit between the terminals of the breaker, namely one between the fixed 7,0 contact 14 and the contact surface 131 in each of the two contact assemblies and one between the contact surface 101 of each contact assembly and the appertaining poker contact 11 of the moving assembly The 7. total length of break provided for by each of the shrouded contact assemblies in conjunction with the moving assembly equals the final distance between the poker contact 11 and the contact surface 101 in the shroud >sf (which distance substantially corresponds to the travel of the moving assembly) plus the final distance between the contact surface 131 and the contact 14, this latter distance being determined by the stop 19 on the arm S) 9; in other words the travel of the moving assembly is less than the total break length by an amrount commensurate with this latter distance Furthermore as the breaks thus provided for by each contact assembly are f Sl defined adjacent opposite sides of the arcing shroud containing the assembly they can be arranged to overlap to some extent, thus reducing the necessary height of the shroud to contain the contact assembly and sur 3 o round

the arc paths formed across the breaks. Yet again, as the minimum length of each poker contact 11 is determined by the length of break provided between it and the cooperating contact surface 101, remembering 100} that the shroud has to surround this break over substantially its entire length and that the poker contact has to be sufficiently long to extend from the exterior of the shroud into contact with its co-operating contact, the P 13 length of the poker contact can be correspondingly reduced. In order to provide a cross-jet arc-extinguishing action in the arc-controlling shroud 4 the side walls of the shroud are formed, at 110 positions offset sideways from the paths of the arcs which will be drawn between the co-operating contacts on opening the breaker on load, with a number of exhaust passages 21, 22 leading from the arcing chamber in a i 15 transverse direction with respect to the arc paths The exhaust passages 21 at the side of the shroud 4 remote from the shroud of the other contact assembly associated with the bridging conductor 12 may pass directly 120 ft to the exterior of the shroud, but in order to avoid the two shrouds exhausting towards each other, the exhaust passages 22 in the other side wall of the shroud lead from the arcing chamber 5 into a common passage 23 12 ' which extends downwardly through the side wall and opens to the exterior through the bottom of the shroud exhaust through this passage accordingly being directed downwardly Alternatively the exhaust 13 o L which is also metallic and in turn carries or 65 constitutes said first contact of the assembly. 7 A contact assembly as claimed in


* GB785236 (A)

Description: GB785236 (A) ? 1957-10-23

Method of and apparatus for producing coatings of hard carbides


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PATENT SPECIFICATION Date of Application and filing By E m Complete Specification Mar11, 1955. Adz, Application made in Germany on Mar 12, 1954. Application made in Germanyon Sept 6, 1954. ____ Application made in Germany on Sept7, 1954. Complete Specification Published: Oct 23, 1957. 785,236 P No 7220, 55. -1 Index at Acceptance:-Class 82 ( 2), F( 1 B 2: 2 M: 2 Z 2: 3 D: 3 E: 4 E: 4 F: 4 K: 5). International Classification:-C 23 c. COMPLETE SPECIFICATION Method of and apparatus for producing Coatings of Hard Carbides. We, METALLGEVSELLSCHAFT AI'TIENGESELLSCH-AFT, of 45 Bockenheimer Anlage, Frankfurt-on-the-Main, Germany, a body corporate organised under the Laws of Germany, 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 a method of and apparatus for producing coatings of hard carbides. The hard carbides of the metals of the 3rd to 6th groups of the periodic system include, for the purposes of this description and claims, the carbides of the elements boron and silicon The carbides of these groups are distinguished by excellent physical and chemnical properties They have 20therefore acquired, in the last few decades,

increasing importance in the manufacture of tools and machine parts which are subject to considerable wear or attack by corrosion or oxidation Workpieces of hard carbides are usually prepared by powder-metallurgical processes in which binding metals such as nickel, cobalt and iron are added to the carbide A considerable proportion of the cost of manufacturing these workpieces is due to the raw materials and the production of the hard carbides It is therefore desirable to use the hard carbides in the form of coatings on metals, alloys, and possibly also on ceramic materials. The use of coatings of hard carbides is complicated by the fact that elementary carbon is usually deposited together with the carbide and this carbon deposition can be avoided only with difficulty Thus the coatings generally contain free carbon, which considerably impairs their cohesion As a result, coatings of this type tend to peel off even when subjected to slight stresses and particularly when subjected to frictional and impact stresses. The deposition of high melting carbides by the reaction of a halide of the carbideforming metal with hydrocarbons in the presence of hydrogen has been known for a long time, and has been exhaustively in 50 vestigated particularly by the incandescent lamp industry These investigations were essentially carried out by depositing the carbides on a filament of a high melting material (tungsten, molybdenum, or graphite) 55 All workers were unanimous in reporting that temperatures of at least 1300 'C were necessary for depositing the carbides under these conditions. Such high temperatures are very disad 60 vantageous for many base materials, and steels could not be used as base materials for carbides deposited at such temperatures. Apart from this disadvantage, known processes also encountered the difficulty that 65 the simultaneous deposition of free metal or free carbon was difficult to avoid. It is an object of the present invention to deposit these coatings as far as possible at temperatures at which steels, particularly 70 tool steels, may still be used as base material without being damaged. The thermodynamic calculations made in the laboratories of the Applicant Company have shown that the hard carbides may be 75 formed from the halide of the carbide-forming metal and hydrocarbons such as methane, at substantially lower temperatures than had previously been used Practical experiments have shown that above 900 C, par 80 ticularly in the temperature range between 900 and 1200 'C, excellent coatings can in fact be formed A number of tool steels have been found to be particularly good base materials for the application of coatings, 8 i particularly coatings of the very hard titanium carbide. It has now been found that it is possible, in a simple manner, to

deposit the hard carbides of the metals of the 3rd to 6th groups 90 785,236 if the periodic system, for example titanium, vanadium and tungsten carbide, in the form if coatings on metallic and non-metallic supports, without depositing disturbing amounts of elementary carbon or the metal he carbide of which is to be formed, if, -or the purposes of deposition, use is made of gas mixtures which contain hydrogen, a halide of the carbide-forming metal and an amount of volatile hydrocarbons, not greater than that corresponding to equilibrium between carbon and hydrogen, and the volatile hydrocarbons at the temperature of deposition and if the amount of halide of the carbide-forming metal present is no more than, but preferably is as much as, will react with the volatile hydrocarbons to form the metal carbide Such gas mixtures can be produced if a hydrogen halide, with or without hydrogen, is allowed to act on the carbide or carbides of the carbide-forming metal or metals, vith or without free carbon The corresponding metal halide or halides, volatile hydrocarbons and hydrogen are then formed. This gas mixture is produced at a temperature which is lower than the temperature at -which the hard carbide is deposited on the surface to be treated For example, in order to produce titanium carbide coatings hydrogen chloride and/or chlorine, if desired together with hydrogen is passed into the halide-forming zone of the deposition apparatus at temperatures from 500 to R-O-C over titanium carbide and the resulting zas mixture is then passed into the deposition zone which has a temperature of 900 to u 200 WC It is also possible to introduce additional hydrogen into the deposition zone. This procedure is possible because equilibrium is displaced with increasing temperatures in the direction of carbide formation, and at the lower temperatures in the halide forming zone, equilibrium is still on the side of the halide The gas should be passed from the halide forming zone, which has a low temperature, into the carbide forming zone, which has a higher temperature, at such a rate of flow that the carbide is not deposited during transference but only on the surfaces to be provided with the coating. in a similar manner coatings of carbides can also be obtained by passing hydrogen :ialide, with or without hydrogen, over the metal, e g titanium, the carbide of hliich is to be deposited A gas mixture of hydrogen and metal halides, for example titanium hal-des, is thus formed A mixture of hydrogen and volatile hydrocarbons which is in equilibrium with carbon at the temperature of deposition is added in the carbide-forming zone to this gas mixture containing the hal-de vapours The amount of the added mixture is such that the hydrocarbons are at east enough to react with the metal halide to fo m the metal carbide This can be achieved by adjusting the speeds of flow A mixture

of this type of hydrogen and volatile hydrocarbons is preferably produced by passing hydrogen over carbon at a temperature which is at least as high as the tern 70 perature in the carbide forming zone. The process of the present invention Caun for example be carried out in the apparatus illustrated in the accompanying drawing. Solid titanium carbide is situated in chamiber 75 1 Hydrogen chloride is introduced through the pipe 2 and forms titanium tetrachloride and volatile hydrocarbons such as methane. at the temperature of 500 to 700 C, wvhich prevails in the chamber l The eases 80 charged with titanium tetrachloride and volatile hydrocarbons pass through the narrow apertures in the plate 3 at high speed and enter the chamber 4 in which the workpieces to be coated with the carbide are situated 85 In this part of the reaction chamber a temperature of 900 to 1200-C is maintained. Equilibrium between the metal halide, the volatile hydrocarbons, the hydrogen and the hydrogen chloride is thus displaced in 90 the direction of the formation of carbide. The titanium carbide thereby formed is deposited on the surface of the workoieces to be coated Hydrogen chloride hydrogen. and the residues of metal halide and the 95 residues of hydrocarbons corresponding to equilibrium, which are extremely small leave the reaction furnace 5 through the branenc 6. A particular advantage in these embodiments of hle invention is the formation of 100 the metal halide, for example titanium tetrachloride, inside the aparatus The halide can be formed from the metal to be e sited and/or from a compound of this meta L for example the carbide, which compound 105 is capable of forming a halide with the halogen or hydrogen halide under the conditions prevailing in the apparatus. By virtue of the fact that the halide is formed it situ in the reaction chamber, such 110 difficulties in ensuring tightness thereof are avoided as are encountered when introducing the halide into the reaction chamber in view of the reactivity of said halide so that this embodiment in which the halide is formed 115 int situt in the reaction chamber is of particular advantage. It is also possible, when applying carbide coatings according to the process of the present invention, to use the metal halide or 12) halides as such and to evaporate it or tho m into the reaction chamber and to bring it or them into contact in the carbide forminp zone with a gas mixture containing hydrogen and volatile hydrocarbons in ratio of equili 125 brium with carbon at the temperature corresponding to the deposition temperature. It is also possible to produce, by the process of the present invention, coatings which consist of mixtures of various carbides or of 130 7 g 5,2366 ji,-xtures of at least one carbide with at least a

ne nitride of the metals of the 3rd to 6th gr-oups of the periodic system These mixed coatings have similar properties to coatings consisting of one carbide In order to prociuct coatings of mixed carbides, a mixture of the different metals, alloys of the carbide forming metals and/or compounds of the sa-ne, for example carbide, can be introl Oduced into the halide forming zone Halides are produced there with the aid of hydrogen halide, as in the case of the pro. duction of single carbide coatings The carbides are then deposited on the surfaces to be coated from the halides However, the halide forming zone can also be subdivided into individual areas separate from one another, and in each of these areas the halide or halides of only one of the carbide forming metals can be produced and passed to the carbide forming zone separately from the halide or halides of the other metals. Nitrides may also be incorporated in the coatings, for example by adding nitrogen and/or compounds giving up nitrogen or a -as containing nitrogen, in the coating forming zone to the mixture of halides and volatile hydrocarbons in equilibrium with hydrogen Ammonia can for example be used as such a compound In cases in which nitrides are aiso to he deposited in the coatings, the operation must be carried out in the absence of oxygen and its volatile compounds, particu'arlv va er vapc-ur. In all variations of the process of the present invention, however, in order to produce the halides of the carbide forming metals, the hydrogen halide can be wholly or partially replaced in the halide forming zone by the halogens, particularly bromine This is particularly advantageous when carbide coatings of those metals, the halides of which are easily reduced by hydrogen, are to be deposited. It has been found that with the aid of this process it is possible to produce titanium carbide coatings which, when applied to a smooth metal surface, are distinguished by very slight surface roughness and an extremely fine grained, compact structure. These coatings can consequently be used as surface protection for workpieces, tools, and machine parts which are subject to mechanical wear, particularly sliding friction, erosion, and corrosion. The coatings are deposited practically uniformlv on the surface to which they are to be applied, so that they reproduce said surface together with any irregularities. When the titanium carbide coatings are used as surface protection of workpieces, tools, and machine parts which are predominantly subject to mechanical wear, particularly sliding friction, it is advantageous to machine very accurately at least the surfaces of said objects which are exposed to heavy mechanical stresses, before the coatings are a Dplied Titanium carbide coatings are then obtained with a surface

roughness of about 2 l t This roughness can be reduced to con 70 siderably below 1 p by polishing, for example with diamond dust, boron carbide powder, or also with graphite powder produced by a cutting process such as planing. For machine parts and tools having a 75 rough surface, for example files and rasps, the surface of the base material is brought to the final shape and the carbide coating then applied. Suitable base materials for workpieces, 80 tools, and machine parts which are to be provided with a coating of titanium carbide have been found to be steels which can be hardened by quenching in air and/or oil, particularly dimensionally stable steels, i e 85 steels which do not wart or otherwise change shape on being heated, containing l l to 150 ', of chromium and 1 5 to 2 50 o, of carbon, hot working steels containing 4 to 10 % of tunjsten, and highlv hardened steels containing 90 4 %Y of nickel and l to 1 5 ' of chromium. In addition to the alloying components mentioned, these steels can also contain smaller amounts of other alloying components, for example silicon, manganese, molvbdenum 95 and vanadium When coating these steels with titanium carbide, care must be taken that the steels are not overheated. After applying the coatings at 960 to 10005 C, the steels, without any additional 100 quenching steps, have hardnesses which, depending on material and test conditions, lie between 400 and 700 HV, that is to say between about 42 and 59 HRC Such materials thus consist at least partly of a relativelv 105 moderately hard base material having a very hard coating They can be used without further hardening as basic material for those workpieces, tools and machine parts which are subject to sliding friction without high 110 pressures, erosion, and corrosion Such workpieces may for example be used for jewelled bearings, precision machine bearings, sensing members in measuring instruments, valves such as shut-off slide valves, 115 and movable parts of machines, particularly internal combustion engines It is particularly advantageous to use such materials for parts of spinning machines, such as thread guides 120 If the workpieces, tools or machine parts are subject to sliding friction combined with high pressures, such as for example drawing tools and bearings, it is advantageous to bring the base material, which can consist 125 of a dimensionally stable steel, after application of the titanium carbide coating, to the desired working hardness by heat treatment in an atmosphere of a protective gas, preferably of nitrogen purified by treatment with 130 7 78 _,236 magnesium, calcium, titanium, andlor nitrides thereof In this case, the procedure may be to remove the by-products of the reaction, particularly the hydrogen halides, from the furnace after application of the carbide coating and to quench in

an atmosphere of a protective gas, for example hydrogen free from oxygen, and/or nitrogen The gas used as the protective gas atmosphere is a gas which is free from oxygen or compounds giving up oxygen, preferably nitrogen purified by treatment with magnesium, calcium, titanium and/or nitrides thereof When working in this way, the temperature at which the coating is formed is preferably selected to be equal to the required hardening temperature, and the quenching or cooling for the purpose of hardening is effected directly after the formation of the carbide. Quenching can be effected by passing the reaction material into a cooled zone of the reaction vessel or by passing the same into a quenching bath or a hot bath, for example composed of a lead-zinc alloy followed by air cooling. It is also possible to apply hard carbide coatinrgss in accordance with the invention to harden workpieces which are not themselves hardened.


* GB785237 (A)

Description: GB785237 (A) ? 1957-10-23

Improvements relating to the control of pneumatically operable gear boxes


PATENT SPECIFICATION 7 Date of filing Coomplete Ipecyication: May 4, 1956. Application Date: Mawrdi, 18, 1955 No 7997/15 5. g y 1 O Complete Specification Publilshed: Oct 23, 1957. Index at Acceptance -Class 80 ( 2), D 3 (A: E). International Classification:-F Orh.

COMPLETE SPECIFICATION. Improvements relating to the Control of Pneumatically Operable Gear Boxes. We, WES Ti NGHOUSE Bn ACE & SIGNAL COMPANY L Il ITED, a Company incorporated under the Laws of Great Britain, Jo HN HORATIO LESLIE HIGGI Ns, both Subjects of the Queen of Great Britain, and all of 82 York Way, King's Cross, London, N 1, England, 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 the control of pneumatically operable gear boxes. Such gear boxes are usually controlled by a control valve device, herein referred to as of the kind described, operated by a gear change lever movable from a neutral position, through a so-called gate, to any one of a number of operative positions in each of which it opens a valve to admit fluid under pressure to a cylinder which causes the meshing of the selected gear. Dual range gear boxes are known which have two ranges of gears, both operated by the movement of the lever of a single control valve device to the same operative positions, one or other of two gear ranges being selected by a separate two-position range selecting lever. According to the invention, a control valve device of the kind described, for the operation of a multi-range gear box, comprises a rangeselecting valve mechanism operable by a movement of the gear change lever, different from and prior to its movement from said neutral position into any one of said operable positions, to cause the selection of the desired range of gears. Preferably, the gear change lever is supported by a spherical bearing, about which it is rocked as said lever is moved between its several positions aforesaid, said different movement being a rotational movement about its longitudinal axis from a first 45 range selecting position to a second range selecting position. Preferably, also, a groove is formed in the lever surface of the spherical bearing, a spring loaded operating rod projecting into said 50 groove at all times whilst the gear change lever is in its first range selecting position and forced out of said groove to operate said range selecting valve mechanism by the turning of said lever into its second range 55 selecting position. One or more spring loaded locking members may be provided each engaging a corresponding groove formed in said spherical lever surface whilst said lever is in one or 60 other of its range selecting positions to locate said lever in said positions. The invention is illustrated by way of example in the accompanying

drawings of which:Figures 1 and 2 are just sectional elevations of one control valve device of the kind described embodying the invention; Figure 3 is a plan view on an enlarged scale showing the gate which defines the 70 several operative positions to which the gear change lever may be moved; and Figure 4 is a sectional view taken along the line A-A of Figure 2, also to an enlarged scale 75 Referring now to the drawings, the gear change lever 1 for the selection of the gears of a dual range gear box extends, in usual manner, through a system of slots 4 formed in the top of the casing 5 of the device and 80 constituting the usual so-called gate The gear lever is mounted, within the casing, in a spherical bearing comprising a spherical enlargement 6 of the lever located by top and bottom bearing plates 7, 71 formed with 55 central circular apertures with spherical lPrice 3 s 6 d l 1 j f -J, t S u 359237 4.1-,j , z,, C 6 1 phet, 25 , 785,237 faces 11, the arrangement being such that the lever may be rocked in any direction in the bearing, subject to the limitations of the gate Rotatably mounted on the lower end of the gear change lever is a ball 13 which engages one or other of a number of rockers 14 which it depresses as the lever is rocked, to operate, through push rod 20 in the usual manner, one or other of the valve mechanisms l Is (not shown) located in a base portion 16 of the device, to admit compressed air to the appropriate gear selecting cylinder in the gear box. Formed in the surface of the spherical 1 I portion of the gear change lever, between the two bearing plates, is a groove 17 into which projects the nose of a spring loaded operating rod 21 slidably mounted in a bore provided in a spacer 8 which is clamped by bolts 36 enl (Figure 4) between the twvo bearing plates 7 and 71 A spring 23 biases the operating rod 21 towards the position in which it is shovwn in the drawing, with its nose projecting into the groove 17 The other end of the rod 21 abuts one arn of a pivoted valve operating lever 24 The groove 17 is so shaped that it continues to accommodate the nose of the operating rod 21, regardless of the gate to which the lever 1 is moved, so long as the lever is not rotated about its longitudinal axis Rotating the gear change lever through 90 , however forces the nose of the operating rod 21 out of the groove and causes it to turn the pivoted valve I operating lever 24 about its -pivot 25 to operate a, range selecting valve device which controls the supply of compressed air to the range selecting mechanism of the gear box. In the example illustrated in the drawing the range selecting valve device comprises a ball valve 32 normally seated on a seating 37, in which position communication is established between a compressed air supply port 35 and an outlet port 33 to supply compressed air to the range selecting mechanism (not shown) of the gear box The turning of the valve operating lever 24 about its pivot 25 by the operating rod

21 transmits an upward thrust, through a ball 26, to a sleeve 27 slidable in a bore 38, which thrust is applied, through a spring 28, -to a movable abutment 29 which is accordingly moved upwards and, by means of a stem, 31, forces ball valve 32 off its seat 37 and onto its alternative seat 34 The supply of compressed air to the range selecting mechanism is thus cut off and the outlet port 33 is p Olaced in communication with the atmosphere through a port 30 Also formed in the i O surface of the spherical portion 6 of the gear change lever, diametrically opposite the above mentioned groove 17, is a second, similar, groove 22 engaged by one or other of a pair of spring loaded locking members 9, 18 for the purpose of locating the gear change 6 ( 5 lever in one or the other of its range selecting positions, the two locking members being spaced apart by 90 ' around the spherical portion of the gear change lever. In order to avoid the danger of attempting 7 X) to select a different range of gears whilst a gear of one range is already engaged, that part 2 of the gear change lever which passes through the slots of the gate is made square in cross section and of such dimensions that 75 the lever can be rotated only when it is in its neutral position, that is to say with no gear engaged.
