5551 5555.output

* GB785959 (A)

Description: GB785959 (A) ? 1957-11-06

Improvements in and relating to turbines having adjustable guide vanes

Description of GB785959 (A)

PATENT SPECIFICATION Inventors: LAWRENCE MILTON BOYD 7 V and JOHN CRICHTON MCKEAN Date of Application and filing Complete Specification: Dec 9, 1955. No 354121/55. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Classes 110 ( 1), C 2 83 A( 1: 3); and 110 ( 3), B 2 V 13, H 2 D 3. International Classification:-FO 3 b FO 5 c. COMPLETE SPECIFICATION Improvements in and relating to Turbines' having Adjustable Guide Vanes LIMITED, a Corporation organised under the laws of Canada and whose post office address is P O Box 220, in the City of Montreal, Province of Quebec, Canada, 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 has reference to improvements in and relating to turbines adapted to be used also as pumps, said turbines having adjustable guide vanes and is concerned more particularly with the provision of improved means for locking the guide vanes against vibration and oscillations when the turbine is being used as a pump. The invention resides in the provision in a turbine having adjustable vanes of means for locking each adjustable guide vane in its adjusted position comprising upper and lower stems on said guide vanes, an upper annular tapered bearing seat, a tapered shoulder at the upper stem of said guide vane complementary to the upper bearing seat, a lower annular tapered bearing seat, at the lower stem of said guide vane, an annular tapered ring complementary to said lower tapered bearing seat, and a lifting rod passing through said guide vane stems adapted to bring said tapered shoulder and tapered ring into wedging

contact with their complementary tapered bearing seats to lock the guide vanes against rotation from their adjusted position. Preferably the annular tapered rings are of sectional form and springs tending to hold the tapered shoulders and tapered rings out of engagement with their complementary bearing seats are preferably provided although, of course, the pressure of the springs is overcome by the action of the lifting rod when the vanes are locked in their adjusted position The upper annular bearing seats are preferably adjustable axially lPrice 3 s 6 d l with respect to the axes of the guide vane stems with which they are associated, for the purpose of taking up wear without dismantling the turbine 50 In the preferred way of carrying out the invention the turbine comprises a head cover and a bottom ring, a turbine runner, a series of upper guide vane bearings disposed around the said head cover of the tur 55 bine, a series of lower guide vane bearings disposed around the bottom ring of the turbine and in axial alignment with the upper guide vane bearings, each of said upper guide vane bearings including an annular 60 tapered bearing seat, the said guide vanes having their upper and lower stems journalled in the said upper and lower guide vane bearings, respectively, with the tapered shoulders on said upper stems engaging the 65 annular tapered bearing seats at the upper bearings. The invention will now be described with reference to the accompanying drawings wherein: 70 Fig 1 is a vertical section through a part of a turbine structure showing a guide vane with its position adjusting mechanism and showing the means for locking the turbine guide vane stems at top and bottom 75 Fig 2 is an enlarged part sectional view taken from Fig 1 and showing, in detail, the tapered seating of the upper stem of the turbine guide vane. Fig 3 is an enlarged part sectional view 80 taken from Fig 1 and showing in detail the locking mechanism for the lower stem of the turbine guide vane. Fig 4 is an enlarged section showing the lower stem locking means in the unlocked 85 position and the spring washer holding the locking means separated. Fig 5 is a view similar to Fig 4 showing the lower stem locked and the spring washer compressed 90 Fig 6 is a plan view of the sectional locking ring. 35,959 Referring to the drawings, 5 designates the impeller-runner of the turbine and 6 one of the adjustable guide vanes which are arranged in circular series around the impeller runner in accordance with conventional practice. Each guide vane 6 is equipped with upper and lower stems, respectively indicated at 7 and 8 which are journalled in suitable bearings to provide a fixed axis about which the guide vane may be rotated to

various positions of adjustment. The principal components of the bearing in which the upper guide vane stem 7 is journalled include a sleeve 9 fitted on the lower portion of the stem 7, a bearing bushing 10 surrounding the sleeve 9, an adjustable bearing sleeve 11 in which the bushing is fitted and a cylindrical member 12 in which the sleeve 11 is fitted, said member 12 being formed as an integral part of the outer head cover 13 The adjustable sleeve 11 is held in place by means of the collar 14 and secured by the stud bolts 15 A gland 16 is secured to the upper end of the sleeve 11 and a packing 17 is interposed between the gland 16 and the upper end of the sleeve 11 and about the sleeve 9 The upper pprtion of the sleeve 11 is formed to present a seal ring portion 18 engaging with a similar seal ring portion of the cylindrical member 12 The lower end of the sleeve 11 presents an outer tapered seat 19 and an inner tapered seat 20 The outer tapered seat 19 bears against a complementary tapered seat 21 at the lower end of the cylindrical member 12 The inner tapered seat 20 is opposed to a complementary tap^red seat 22 formed on an integral enlargement or shoulder 23 of the guide vane stem 7 The collar 14 holds the sleeve 11 against rotation but allows for vertical adjustment of the sleeve 11 to compensate for wear on the tapered seats 19 and 20 against the tapered seats 21 and 22. The principal components of the bearing for the lower stem 8 of the guide vane 6 include a sleeve 24 fitted on the stem 8, a bearing bushing 25 surrounding the sleeve 24 and a cylindrical bearing member 26 in which the bushing 25 is secured, said bearing member 26 being formed integral with the bottom ring 27 which encircles the lower end of the runner 5 and is supported by the base ring 28 The bushing 25 is preferably made in two parts, the lower part a acting as a wear ring against which the locking sections 46 are expanded as explained hereafter. The guide vanes 6 are rotated to different positions of adjustment by operating means generally indicated at 30 This operating means 30 may be of any suitable type but is here shown, by way of example, as including an operating lever 31 having one end supported on the upper end of guide vane stem 7 by a wear plate or bushing 32 for rotation about a lever retaining stud 33 screwed into the upper end of the stem 7 An intermediate portion of the lever 31 is secured by a 70 shear pin 34 to one end of a coupling member 35 whose opposite end is secured to the upper end of the stem 7, by a key 36 The end of the coupling member 35 which is keyed to the stem 7 is rotatably supported 75 by a bearing ring 37 through the medium of the bearing plate 38 and bushing 39 The end of the lever 31 remote from the stem 7 is connected by a link pin 40 to a link 41 of a conventional lever actuating mechanism

80 (not shown) The bearing ring 37 is shown as being detachably secured to the inner head cover 42, but, if desired, it may be formed as an integral part of said inner head cover 85 The guide vane 6 and its upper and lower stems 7 and 8 are pierced by a vertical bore 43 in which a hollow lifting rod 44 is fitted for vertical sliding movement The lower end of the lifting rod 44 carries a lifting cap 90 supporting thereon a circular series of tapered locking sections or segments 46 presenting tapered surfaces 47 opposed to a tapered seat 48 The upper surface of the lifting rod cap 45 is undercut to provide a 95 seat at 49 the radial depth of which will allow for radial movement of the sections 46 A spring 50 is interposed between the central portion of the lifting cap 45 and the lower end of the guide vane stem 8 This 100 spring may be of the beilville type or of any other form having sufficient strength to lift the guide vane 6 and effect engagement of the upper tapered seats 20 and 22 in one direction and in the other direction effect 105 separation of the tapered sections 46 from the tapered seat 48. The upper portion of the lifting rod 44 extends through the lever retaining stud 33 into a hydraulic cylinder 51 which is sup 110 ported by the head cover assembly of the turbine through the bracket 52 A piston 53 reciprocating in the cylinder 51 is secured to the lifting rod 44 by the retaining nut 54 The cylinder 51 is provided with a 115 pressure connection 55 through which pressure fluid is supplied to and exhausted from the cylinder 51 to effect displacement of the piston 53 A drain opening 56 on the upper end of the cylinder allows fluid which 120 has accumulated on the top side of the piston 53 to be drained off Provision for greasing the lower stub shaft 8 and bushing 25 is provided at 57, the grease being forced down through the hollow 125 lifting rod 44 and into the bearing through the radial aperture 58. When the turbine is to be used as a pump the guide vanes 6 may be adjusted to any desired position by the operating means 30 130 785,959 vanes against rotation from their adjusted position.

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* GB785960 (A)

Description: GB785960 (A) ? 1957-11-06

Composite refractory rail for pusher-type furnaces


PATENT SPECIFICATION 785,960 Date of Application and filing Complete Specification Dec 21, 1955. No 36664/55. Application made in Germany on Dec 29, 1954. Complete Specification Published Nov 6, 1957. Index at acceptance: lass 51 ( 2), B 7 A 10. International Classification: -C 22 b. COMP 1 LETE SPECIFICATION Con,,A Inos Gte ceto 61 Lry fm 1 fr 7,',aslhe L,-ypoe F;urnaces We, THERMIO INDUSTRIEOFENBAU G.m b H, of Dusseldorf, Germany, a German 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: - The present invention relates to a composite refractory rail for use in pushertype furnaces. During heat treatment in pusher-type furnaces, the material to be heated is conveyed through the furnace on rails After having been introduced into the furnace, it is heated from the cold state (charging temperature) to a high temperature (the so-called drawing temperature) and is then removed from the furnace. The rails are generally constructed of highly heat-resistant steel and are watercooled Rails of this type can scarcely withstand the high stresses within the furnace As a result of the water-cooling, high heat losses occur which are uneconomical. An object of the invention is to provide a composite refarctory rail which withstands the high stresses set up in the furnace for example high temperatures, considerable temperature fluctuations, high compressive and abrasive stresses and the action of slag, while avoiding the watercooling of the rail. According to the invention a composite refractory rail, for use in pusher-type furnaces, comprises a plurality of rail sections joined together wherein each rail section is constructed from a material

selected to withstand the stresses and heat to which the said rail section is subjected in the corresponding temperature zone of the furnace whereby no cooling of the said composite refractory rail inside the furnace is necessary The composite refractory rail may, with advantage, comlPrice 3 s 6 d l prise three rail sections joined together. Preferably, a rail section in a temperature range of from 20 ' to 600 ' C consists of highly heat-resistant steel, more especially chrome-nickel steel In the temperature regions of from 600 O to 9000 C, a rail section may consist of ceramic material, such as silicon carbide having high resistance to sudden temperature changes and to abrasion In the temperature ranges above 900 ' C, a rail section preferably consists of ceramic material having high resistance to pressure and heat, as well as high resistance to the action of slag and to abrasion Especially. it has proved expedient to manufacture a rail section in this region from a fused mass of oxides, which has a softening temperature above 1750 ' C. The invention without limiting it will be more fully explained and illustrated with reference to the accompanying drawings wherein: Figure 1 shows the variation of the temperature along the length of the furnace. Figure 2 shows a diagrammatic longitudinal view of a rail for pushertype furnace according to the invention. The material to be heated is introduced in the cold state into the furnace, is heated therein and is removed therefrom on reaching the drawing temperature, whereby its temperature rises in accordance with a curve adapted to its material properties. In Figure 1, three temperature curves 4, 5 and 6 are plotted along the length of the furnace Such a temperature curve, for example 4 will be substantially constant with equal forward-feed speed and equal dimensions (weight) of the material introduced In each zone of the furnace, a temperature range will thus be set up which is adapted to the speed of forward 785,960 feed and to the weight of the material to be heated. However, if the speed of forward feed and/or the weight of the introduced material, and accordingly also the output of the furnace, are altered, the temperature range and the temperature curve will vary until a new, substantially constant temperature range has been set up. The heat-absorbing capacity of the material to be heated depends primarily upon the temperature difference between the interior of the furnace and the material being heated The heat absorption is therefore greatest in the first part of the furnace in the neighbourhood of the inlet aperture, since the material to be heated is still relativel

cold and the temperature difference between the interior of the furnace and the material to be heated is at a maximum. As the heating increases and the material to be heated is moved further in the longitudinal direction of the furnace, the temperature difference between the material to be heated and the interior of the furnace decreases, and the heat absorption of the material being heated is reduced On variation of the output of the furnace, for example by virtue of a changed speed of forward feed or variations in the weight of the material to be heated, the temperature fluctuations in the material to heated will therefore become considerably greater in the forward and central part of the furnace than in the rear part of the furnace (delivery end). The rails are in direct contact with the material to be heated and are therefore exposed to the considerable temperature fiuctuations of the surface of the material to be heated in the forward part of the surface As the material progresses further in the longitudinal direction towards the delivery opening, the temperature of the material increases, but the temperature fluctuations have a constantly smaller effect The rails are here highly heated and their compressive strength decreases. As the material being heated progresses further, and with further heatihg, it may happen that the surface temperature of the material being heated rises above the melting temperature and flowing slag runs on to the hearth or on to the rail supporting the material being heated. The rail may therefore still be exposed to the action of slag shortly before it is pushed out of the furnace. The curve 4 shown in Figure 1 will generally be produced in normal operation The final temperature in the present example is in the neighbourhood of 12500 C. The curve 5 is obtained when the oulput of the furnace is lower The material is rapidly heated (for example at low forward-feed speed) and rapidly approaches the final temperature, so that as it passes 70 further through the furnace it only undergoes a small increase in temperature. The curve 6 is obtained with higher furnace output The forward-feed speed of the material being heated is high I so 75 that the temperature in the forward part of the furnace increases only slowly and the material is only slowly heated to its fihal temperature as it continues to travel through the furnace 80 The production of curves 5 and 6 will be more fully explained with reference to two practical examples. In the event of disturbances during rolling, the output of the furnace is 85 greatly reduced, and the curve 5 is substantially set up After

the disturbance, the forward-feed speed and consequently the output will be greatly increased in order to achieve the required daily output 90 of the furnace, and the heating will follow the curve 6. It may also happen tlbat with unequal charging of the furnace, ingots having smaller dimensions and lower weight will 95 be pushed into the furnace after ingots of large dimensions and great weight, so that with equal speed of forward feed the normal curve 4 will change to the curve 3. Normally the heating in the individual 1 01 zones of the furnace will be automatically regulated in accordance with the surface temperatures of the material being heated, but temperature fluctuations in the material can never be entirely avoided 105 owing to the heat stored in the furnace lining. The material to be' heated travels substantially through three zones 1, 2 and 3 in the course of its heating In zone 1, 110 the material is heated up from room temperature, for example 20 C to a temperature of about 600 C The rails in this zone are thus stressed mainly by temperature variation 115 In zone 2 high stressing by sudden temperature changes mainly occurs, since in this zone relatively high temperature fluctuations occur in accordance with the difference in values between the curves 5 120 and 6. In zone 3 (delivery part), the temperature is relatively regular, but is very high, so that considerable resistance to heat and compression is required here and 125 in addition attack by slag must be expected In all three zones, the rails are in addition exposed to considerable abrasive forces. If slide rails were constructed of the 130 so loading of the material supporting the sections (fireclay or the like) The rail sections may have a substantially trapezoidal cross-section as illustrated, and the upper corners may be rounded 70 The invention is in no way limited to the embodiments described above More especially, materials of a similar type which have proved suitable to withstand the stresses described may also be 75 employed for the rail sections in the various zones. As is apparent from Figure 2, the rail has a trapezoidal form which has proved suitable when employing ceramic 80 materials However, the rail sections in the various zones may 'be given another desired form adapted to resist the stresses in these zones.

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* GB785961 (A)

Description: GB785961 (A) ? 1957-11-06

Device for replacing a normally active apparatus in a transmission system orreplacing a normally used route by a spare apparatus or a spare route in theevent of a breakdown in the normally used apparatus or route


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NL84039 (C) NL84039 (C) less Translate this text into Tooltip

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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.

PATENT SPECIFICATION Date of Application and filing Complete Specification 785961 Dec 30, 1955 No 37416/55. Application made in Netherlands on Dec 31, 1954. Complete Specification Published Nov 6, 1957. Index at Acceptance:-Class 40 ( 4), R 11 G. International Classification: -HO 4 b. COMPLETE SPECIFICATION Device for Replacing a Normally Active Apparatus in a Transmission System or Replacing a Normally used Route by a Spare Apparatus' or a Spare Route in the event of a Breakdown in the Normally used Apparatus or Route We, STANDARD TELEPHONES AND CABLES LIMITED, a British

Company, of Counnaught House, 63, Aldwych, London, W C 2, 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:- The present invention relates to automatic switching arrangements for electric transmission system in which spare equipment is automatically substituted for normally operating equipment which has failed. In such arrangements it is necessary that the automatic change-over shall be reliable, and shall take place sufficiently quickly that the normal operation of the transmission system is not interrupted This last requirement is often difficult to meet when mechanical relays are used for switching, and such relays are also liable to introduce high and variable contact resistance, par icularly when the currents passing through the contacts are small. It has hitherto been proposed to have both the normal and the spare equipment permanently cenneced in circuit, with the spare equipment rendered inoperative by blocking one or more valves by means of a blocking voltage derived from the normal equipment. When the normal equipment fails, the blocking voltage is removed and the spare equipment then comes automatically into service. Even with this arrangement there is some delay before the spare equipment comes into operation, and transients are liable to be generated Both these defects may be serious objections in systems conveying telegraph channels; at a speed of 50 bauds, for example, tbhe switch-over time should not exceed about 3 milliseconds In a similar way the normal fault-alarm arrangements may be interfered lPricr 3 s 6 d l with if the switch-over is too slow, or if transients are generated. It is also a disadvantage of this type of arrangement that no alarm can be given if valves in the spare equipment become defective; and moreover, the life of valves which are held in a cut-off condition is considerably shorter than that of valves maintained in normal operation. The present invention is based on recognition that it is possible to have the normal and spare equipment both permanently coupled to a common circuit and both maintained in normal operation, the coupling being such that the spare equipment delivers no power to the common circuit except when the normal equipment fails. The invention accordingly provides an arrangement for replacing normally active equipment in an electrical transmission system by similar spare equipment, in the event of the normally active equipment becoming defective, the spare equipment being maintained in operative condition when out of use, comprising a hybrid coil circuit arranged to couple the outputs of the normally active equipment and of the

spare equipment to a common output circuit, the said equipments being connected respectively to a pair of conjugate outlets of the hybrid coil circuit, an amplifier connected between the output of the normally active equipment and the corresponding outlet, a negative feedback connection between the common output circuit and the input circuit of the amplifier, and means operating in response to a failure of the normally active equipment for blocking the said amplifier. The invention will be described with reference to the accompanying drawings in which:Fig 1 shows a block schematic circuit diagram of a known automatic change-over arrangement; Fig 2 shows a block schematic circuit diagram of an embodiment of the invention; Fig 3 shows circuit details of the changeover circuit shown in Fig 2; and Fig 4 shows a modification of Fig 3. While the embodiments of the invention described below as examples of the invention are concerned with the carrier current supply arrangements for a communication system, the invention is also applicable, for example, to a signal communication system where a spare system is provided to r;place automatically the normally used system when the latter fails. Fig 1 shows a knvin arrangement including a normal circuit 1 and a similar spare circuit 2 connected by a hybrid coil circuit 3 to a common output circuit 4. It will be assumed, for example, that the circuits 1 and 2 are connected to two similar sources A and B (not shown) of groups of carrier waves ol di-lerent frequencies for a multi-channel carrier communication system, one being the normal source and the other being the spare source; or a single source could be used for both A and B Tlhe circuit 1 from the A source comprises an awplifler 5 followed by a filter 6 for selecting a particular one of the carrier waves Circuit 2 fron the B source comprises an amplifier 3 and a filter 9 similar respectively to 5 and 6 A control circuit (not shown) is connected over conductors 7 A and 7 B to the amplifiers 5 and 8, and is operated in response to the presence or absence of signal voltage at the outputs of the filters 6 and 9 The arrangement is such that when the circuit 1 is operating normally, a bias voltage is applied from the control circuit over conductor 7 B to bleck the amplifier 8 in the spare circuit 2 If circuit 1 should fail, then the blocking bias voltage is transferred to conductor 7 A, thus blocking the amplifier 5, and unblocking the amplifier 8, so that circuit 4 is now supplied from the spare circuit 2 instead of from the normal circuit 1. With this type of arrangement appreciable time is taken for the blocking voltage to disappear and for the amplifier 8 to become fully operative, and the corresponding interruption may be longer than can be tolerated.

This difficulty is overcome by the arrangement shown in Fig 2, in which both circuits 1 and 2 are maintained in operating condition. The change to the spare circuit is, however, automatically effected by the clange-over circuit shown in the dotted outline 10 This circuit comprises the hybrid coil circuit 3, and an amplifier 11 connecting the normal filter 6 to the hybrid coil circuit 3 A negative feedback connection is made over conductor 12 from the output circuit 4 to the input of the ampli11 As will be explained below, this negative feedback connecton reduces the power delivered from the spare circuit 2 to the output circuit 4 to a negligible fraction, but the power delivered from the normal circuit 1 is not affected To change over to the spare circuit 2, the failure of the normal circuit 1 to 70 deliver any power is made to block the valve 11, whereupon -the feed-back loop being cut, the spare circuit 2 can now deliver power to the output circuit 4 It will be neted that should the amplifier 11 fail, this will interrupt 75 the normal circuit but -will also automatically cause a change-ov-er to thel spare circuit. Fig 3 shows details of the change-over circuit shown in Fig 2 wee amplifier 11 is represented by a valve ', and tlhe hybrid coil 80 circuit 3 comprises two similar three-winding transformers To ana T connected in a conventional way The normal circuit A is connected through an input transformer T,, the step-up ratio of whlich is n, between the con 85 trol grid of the valve V, and ground The anode of V, is connected through the primary winding 1-2 of transformer Ti to a directcurrent source E,, tni negative terminal of which is connected tu ground The cathode of 90 V, is connected to ground through a cathodbias network R,, C and through the output load resistor R,, whicii corresponds to the output circuit 4 of Fig 2. The spare citcuit b is connected to the pri 95 mary winding 1-2 oi the transformer T,, and the upper secondary wiocimngs ef T, and T, are connected in seri;s to a balance resistor R O as shown The terminal 3 of tie lower secondary winding of transfernoer 1 e is con 100 nected to terminal 4 of ti 12 secondary winding of transiorrn'r T and the re naingn, terminals 3 and 4 of tnhs vindings ar 2 connected across the load resistor R Ii one pair of secondary windings of the transroimers T 105 and T, be regarded as connected se-ries-aiding, the others are coinncted series-opposing. Since R is connected in series wikiu the cathode circuit of the valve V,, there is a negative feedback connection corresponding to 12 110 of Fig 2 betwren the output circuit and the input of the valve V,. The input voltage rcm the normal circuit A to transforimer T l is e:, and that from the spare circuit B to transformer T is e,, The 115 connections of tlhe transformers T and T. are such that if the feedback connection be supposed for the moment to

be interrupted. no voltage due to he voltage c, appeals across primnary w >iinding 1-2 of t-ausformer T and 120 no voltage due to the voltage e, arpears across thei primary winding 1-2 of transfcrmer T These two primary windings thus comprise a pair of conjugate outifts Of the hybrid coil network Let the feedback connectionr be res 125 tored; then the voltage across R can be regarded as e + e;-, r e is the component due to en, when e, is supposed zero, and e is the component due to e,, when e, is supposed zero Considering first the effect of e alone, 130 785,961 785,961 the grid-cathode voltage of the valve V 1 will be n e 1-e 1 Iff p is the amplification factor of the valve, then the voltage appearing across winding 1-2 of transformer T, will be /x(n eb-et) If the turns-ratio of the winding 3-4 to 1-2 of transformer T O is C, then the voltage across R% will be p /3 (n ea-eu), and this is equal to e,. Thus eu/n eaix 3/( 1-p 40, so if PA is large compared to 1, then et=n ea, and is independent of Al and IS, and the valve V 1 operates substantially as a cathode follower. Considering now the effect of eh alone, e, is the voltage due to e 1 which appears across the load R, Let the turns-ratio of the winding 3-4 to the winding 1-2 of transformer T, be p Then the voltage e, is amplified by the valve V 1 and appears as pl /,e across the winding 3-4 of transformer To Now e, is equal to the difference of the voltages across the windings 3-4 of transformers T Il and T,, so e V-p eb IL/3 CV and so Thus it will be seen that if pu 3 is large, then e, is reduced to a very small value, and substantially no power is delivered to the load R, by the circuit B. If now by some means the valve V 1 is blocked, then y =O, so that e U=o, but then ev=pe,, and now circuit B delivers output power to the load R,. Accordingly, means not shown in Fig 3 are provided so that the valve V 1 is blocked unless circuit A is delivering power to the transformer T 1 For example, a fixed blocking bias voltage may be applied to the control grid of the valve V,, which bias voltage is normally counteracted by a voltage of opposite sign derived from the voltage ca at the terminals 1-2 of the transformer T 1. It will be noted that if the valve V 1 should fail, the A-circuit will be effectively cut off from the load R,, but because in these circumstances,u=o, a change-over to the spare circuit B will occur, as explained above. As already mentioned, sometimes the A and B circuits may derive their power from the same source, in which case e, and e, will be equal in magnitude In this case the voltages across the winding 1-2 of the transformer T, due to ea and e, will be n e J// and p'.eb// respectively If, furthermore, n=p, and if the connections of circuit B

to the primary winding 1-2 of transformer T, are poled so that the last-mentioned voltages are in opposite phase, then it follows that the voltage across the winding 1-2 of transformer T 2 due to ea and eb acting together will be zero Thus it will be seen that if circuit A becomes defective, a voltage due to eh now appears across the winding 1-2 of transformer T, which could be used to produce a blocking voltage for the valve V,. Unfortunately, however, if the circuit B becomes defective instead of circuit A, a similar voltage will appear across the winding 1-2 of transformer T,, so that a change-over will also occur and this is clearly not desired. This objection can, however, be overcome by the arrangement shown in Fig 4, which is the same as Fig 3 with the addition of the 70 means for deriving the blocking voltage Each of the transformers T, and T, has been provided with an additional winding 5-6 connected to respective rectifier circuits W,, R,, C,, and W 4, R 7, C 4 The rectifier W 2 is con 75 nected to R, and C, by a resistor IR, having no counterpart in the other rectifier circuit. The rectifiers W, and W 4 are directed, as shown, to charge the corresponding capacitors so that the upper terminal is negative to the 80 lower terminal The capacitors C, and C, are connected by a rectifier W 7, directed in the same way as W 2. Under normal conditions, when e, and eh are both normal and equal, no voltage will be 85 generated in winding 5-6 of transformer T 2, so no bias voltage will be developed across capacitor C, However, the voltage e 1 will produce a voltage across the winding 5-6 of transformer T, and a bias voltage will be go developed across capacitor C +, and rectifier W 3 will be blocked. An auxiliary bias circuit comprising the three-winding transformer ME with a saturable core is also provided An alternating current 95 is supplied through a resistor R 8 to the primary winding 1-2 of the transformer M This alternating current may, for example, be obtained from the cathode-heating source for the valve V 1 The secondary winding 3-4 100 is connected to a rectifier circuit W,, R,, C 2 having one terminal connected to ground The rectifier W 1 is directed so that the upper terminal of the capacitor C 2 is made negative to the lower terminal A control winding 105 5-6 of the transformer M is connected in series between the source E, and the winding 1-2 of the transformer T, Thus it will be seen that the anode direct current of the valve V 1 normally passes through the winding 5-6 110 of the transformer M and saturates the core so that substantially no alternating voltage appears across winding 3-4, and no bias voltage is generated by the rectifier W,. It will be noted that the control grid of the 115 valve V 1 is

connected to ground through the secondary winding of the transformer T 1 and through resistors R, and R, Under normal conditions no bias voltage is produced across either of these resistors, and the normal oper 120 ating bias voltage for the valve is produced by the cathode bias circuit R,, Cl. However, if the voltage ea supplied from the normal circuit A becomes zero, a potential appears across winding 5-6 of the trans 125 former T, due to eb, and so a negative bias voltage will be produced by the rectifir W, which cuts off the valve V, The disappearance of the anode current causes the core of the transformer M to become unsaturated, 130 785,961 and the rectifier W, then generates an additional negative bias voltage which holds the valve V 1 in the cu L-ox condition Then, as explained above, the power supplied to the load R, will be derived from the spare circuit B. It will be noted that the bias voltage generated by the rectifier W 4, and derived from eb, holds the rectifier W, blocked, since the resistor R, will ensure that the negative voltage produced by W 2 will be less than that produced by W,. However, if et should become zero instead of e, no bias voltage will be generated by the rectifier W 1, and W will tend to produce a bias voltage as before; but W, will now be unblocked and will prevent the voltage across the resistor R, from rising appreciably above zero Thus no voltage for blocking the valve V 1 can be produced and no change-over occurs. The auxiliary bias circuit also operates to produce a change-over when the valve V, has aged so that the anode current is reduced below some given limit In this case the degree of saturation of the core of the transformer Ad becomes reduced sufficiently for W 1 to produce a negative bias voltage which further reduces the anode current A trigger effect is thus produced which quickly cuts off the valve V 1 This action, of course, occurs even if the A-circuit is normal, and prevents the ageing of the valve VA from adversely affecting the transmission. When the fault causing a change-over has been cleared, the nornmal connection to the A circuit can be restored by temporarily shortcircuiting the resistor R,.


* GB785962 (A)

Description: GB785962 (A) ? 1957-11-06

Improved fluid pressure power steering mechanism for motor vehicles


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FR1123535 (A) US2897684 (A) FR69431 (E) FR1123535 (A) US2897684 (A) FR69431 (E) less Translate this text into Tooltip

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PATENT SPECIFICATION Date of Application and filing Complete Specification: Jan 12, 1956. y No 1097/56. Application made in United States of America on March 28, 1955. (Patent of Addition to No 767,672, dated March 16, 1955). e/Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 79 ( 5), H 9. International Classification:-B 62 d. COM 1 PLETE SPECIFICAT Ir ON Improved Fluid Pressure Power Steering Mechanism for Motor Vehicles We, GENERAL MOTORS CORPORATION, a Company incorporated under the laws of the State of Delaware in the United States of America, of 'Grand Boulevard in the City of Detroit, State of Michigan in the United States of America (Assignees of 'CLOVIS WARD LINCOLN, HENRY SCHUYLER SMITH and PHILIP BARNHART ZEIGLER) 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 fluid pressure power steering mechanisms for motor vehicles. The invention is an improvement or modification of the invention claimed in our Letters Patent No 7 i 67,672, which claims inter alia a fluid pressure power steering mechanism for motor vehicles including a rock shaft operatively connected to ma piston slidable in a cylindrical portion of a steering box, into which portion a steering shaft extends and has a screw and nut connection with the piston, and a control valve comprising a casing fixed to the steering box eccentric to the steering shaft and a valve element linked to the steering shaft by a lever and thrust bearing to 'be axially movable a limited amount by reaction consequent to manual steering effort to direct fluid under pressure from a fluid-pressure pump to one or other side of the piston. The control valve is yieldably maintained in a neutral position by a spring and by the invention, the scope of which is defined by the appended claims, the thrust bearing and steering shaft are resiliently held in a central position corresponding to a neutral position of the control valve by additional springs acting upon the thrust bearing. How the invention can be carried into effect is hereinafter particularly described with reference to the accompanying drawings, in which:Figure 1 is a broken plan, partly in section, of steering mechanism according to the invention; lPrice 3 s6 d 4 Figure 2 is a view in the direction of the arrows 2-2 'of Figure 1 '; Figure 3 is a section on the line 3-3 of Figure 1; Figure 4 is a section on the line 4-4 of Figure 1; and Figures 5 and 6 are sections taken on the lines 5-5 6-6, respectively, of Figure 2. The steering mechanism (Figure 1) includes a steering box 10, in which is j ournaled a rock shaft 12 carrying a rocker arm 14 to which a drag link 16 of the steering linkage is connected. (Fixed to or integral with the rock shaft 12, within the steering box 10, is a gear sector 18, the teeth of which mesh with those of a rack 20 formed integral with a piston 22 reciprocal within a cylindrical portion of the steering box Lateral adjustment of the rock shaft can be effected by means of a screw device 11 (Figure 4). The piston 22 has a recess to accommodate a ball nut 24 and a central bore to accommodate the worm end 2,6 of a steering shaft 2 '8 which has a steering wheel 30 at its upper end. The steering shaft 2,8 is surrounded by a tubular jacket 32, which at its lower end is mounted on an adaptor plate 34 closing the upper end of the 'casing 10 (Figure 3) supporting an oil seal 52 for the shaft 28 The jacket 32 also carries an oil seal 40 for the shaft 2 '8 and a bearing 38 Between the oil seals is formed a chamber 64 within which

is a thrust bearing 3 '6 for the steering shaft 218. The bearing 36 includes a central annular race 44 and 'a pair of outer races 46 for two sets of balls 45 which are enclosed by retainers 50 and urged under a predetermined load against a shoulder 48 on the shaft 218 by a nut 43 Around the outer race 46 adjacent the adaptor plate 34 are two sets of three springs 29 and 29 a, arranged alternately in recesses in the adaptor plate Each spring 29 surrounds a rivet 31 secured to the central race 44 and having a flanged head 51 Each spring 29 abuts against:a flanged head 51 and a washer 53 15#962 against the central race 44 The washer 53 abuts a shoulder on the jacket 32 in the central position and is spaced longitudinally from the adaptor plate 34 by a distance equal to the longitudinal space between the central race 44 and the jacket 32 Each spring 29 a abuts directly against the adapter plate 34 and against the washer 53. The steering shaft 28, which is supported for limited axial movement, carries a seal 54 ior the bore in the piston 22 at its lower tip end, the seal being held in place by a lock ring 56 and retainers 58 The shaft 28 has a central bore through the worm portion con15:nected by a short transverse bore 62 to the chamber 64 The end of the central bore in the piston 22 is closed by a closure cap 66 and the cavity between the end of the shaft 28 and the closure cap 66 is bled through the bore in the shaft. The ball nut 24 is held in place within the piston 22 by a lock ring 68 preventing relative axial movement and by a key 70 in a keyway 72 preventing relative rotary movement The ball nut is mounted on the steering shaft 28 by balls 74 and has a return tube 76 for the balls. A control valve 80 has its casing 82 fixed to the steering box 10 The output of a fluidpressure pump 86 is connected to the inlet of the valve 80, whose outlet is connected by a conduit 114 to a reservoir 84 for the pump 86 A relief valve 88 connects the outlet and inlet of the valve 80 whenever the pressure in the hydraulic circuit becomes excessive. The valve 80 has a spool 90 which is mounted on a stem 150 linked to one end of a lever 92, having a central pivot 93 and a bifurcated 'tongue 94 at the other end between whose arms is engaged the annular race 44 of the thrust bearing 36 on the steering shaft 28 The spool 90 has a central land 10,4 and end lands 105, 106. The inlet to the valve 80 is a passage 108 connected to an annular chamber in the casing surrounding the central land 104 Passages 120 and 122 lead from between the central land 104 and the end lands 106 and 105 respectively to chambers 100 and 102 of iche steering box 10 on either side of the piston 22 Annular chambers in the casing surrounding the end lands 106 and 105 are connected by passages 110 and 116, respectively, to a common outlet passage 1,12 connected to

the conduit 114 The passages are drilled in the body of the casing and steering box and closed off by balls 125 which act as plugs. End land 106 is of somewhat greater length than end land 105;and is grooved to accommnodate:a seal 128, preventing leakage past the free end of the spool which is slidable in a bore in the casing 82 closed by a cap 130. At the opposite end of the bore is a chamber 132 which surrounds the stem 150 and is connected to the inlet passage 108 by a passage 134. A spring 136 surrounds the stem in the chamber 1,32 and thrusts a ring 140 loose on the stem against the end land 105 of the spool 70 and a piston 142 loose on the stem against a shoulder on the stem 150 The piston 142 has an oil seal 144 and its movement is limited by a stop ring 146 held in the casing 82 by a lock ring 148 Movement of the ring 140 is 75 limited by the end of the chamber 132. In operation, the steering shaft 28 is rotated to effect a turn and causes axial movement of the ball nut 24 and piston 22. Resistance of the rock shaft 12 to turning 80 results in a reactionary thrust on the shaft 28 which causes axial movement thereof This axial movement is transferred to the spool 90 by the bearing 36, the lever 92 and the stem Movement of the bearing 36 takes place 85 against the action of the springs 29 or the springs 29 a as the case may be Displacement of the spool causes it to connect one chamber of the steering box to the inlet 108 and the other to the outlet 112 The fluid pressure 90 thus applied to one side of the piston 22 assists the steering shaft 28 in rocking of the rock shaft 12. The fluid pressure in the chamber 132 is always the same as the maximum pressure in 95 the system and presents a resistance to movement of the spool in either direction The differential area of the piston 142 and the end land 105 offsets the different areas of the piston 22 subject to fluid pressure due to the 100 shaft 28 so that the sense of "feel" at the steering wheel 30 is proportionate to the actual steering resistance in which-ever direction the turn is made. The centering action of the spring 136 is 105 assisted by the springs 29 or 29 a associated with the thrust bearing 36 Upon upward reactionary movement of the steering shaft 28, the springs 29, being seated against the washer 53, which abuts the shoulder on the jacket 32, 110 are compressed by the flanged heads 51 This resistance to the upward movement of the shaft 28 is not affected by the springs 29 a, which abut the stationary washer 53 Upon downward reactionary movement of the steering 115 shaft 28, the springs 29 are compressed. Springs 29 on the downward movement afford no resistance, as the washer 53 and the flanged heads 51 ' move together. The steering system described is easily re 120 versble and the dirigible wheels of the vehicle return to the straight ahead position

rapidly and positively on completion of a turn.


* GB785963 (A)

Description: GB785963 (A)

No title available


PATENT SPECIFICATION 785,963 Date of Application and filing Complete Specification jan 27, 1956. No 2732/56 1 Application made in Germany on Jan 27, 1955. Complete Specification Published Nov 6, 1957: Index at Acceptance:-Classes 80 ( 2), D( 2 A: 2 B: 3 A: 3 C: 10); and 103 ( 1), E 1 B. International Classification: -FO 6 h. COMPLETE SPECIFICATION Improvements relating to Change-Speed Gearing Associated with Hydrodynamic Power-Transmitting Apparatus We, DAIMLER-BENZ AKTIENGESELLSCHAFT, of Stuttgart-Untertiirlheim, Germany, a company 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:- The invention concerns change-speed gearing having a hydrodynamic power-transmission unit connected in advance of it, and one or (more particularly) several speeds bridging the hydrodynamic power-transmission unit. The term "hydrodynamic power-trans mission unit " is intended herein to include a hydraulic torque converter and a fluidcoupling.

The object of the present invention is above all to make better use of the hydrodynamic power-transmitter for the purpose of braking vehicles, and further to male a drive operating with a hydrodynamic power-transmitter more economical. Previously existing methods of construction with hydrodynamic power-transmitters have the disadvantage that hydraulic braking is as a rule limited to two ranges, and that at maximum engine speed the power dissipated in the transmitter is far above the permissible operational stress limits, and above the normal capacity of the engine cooling device for forward running A further disadvantage of the known method of construction is that hydraulic braking requires its own regulation programme. On the other hand, the invention provides a drive arrangement allowing the hydrodynamic power-transmitter to be used to the greatest advantage for braking. According to the present invention, a transmission arrangement comprising change-speed gearing and a hydrodynamic power-transmission unit connected in advance of it and capable of being bridged by a clutch which permits the pump wheel of the unit to be coupled directly to the gearing, is distinguished by the fact that the driving train connecting the turbine wheel of the unit to the gearing in parallel with the bridging clutch can be interrupted by a clutch and that the turbine wheel can be braked in such a manner that, with the interrupting clutch disengaged and the bridging clutch engaged, the gearing can be braked by means of the braked turbine wheel by way of the bridging clutch and the hydrodynamic unit. In this connection, the brake acting on the turbine wheel can be operated by a member separate from the gear-change member, although the brake actuating member can be coupled in some circumstances to the operating member for the purpose of attaining braking action. The turbine wheel is preferably coupled to the change-speed gearing by way of a freewheel, in such a manner that when the bridging clutch is disengaged the drive is transmitted through the turbine wheel to the change-speed gearing, and when the bridging clutch is engaged the drive by way of the turbine wheel to the change-speed gearing is interrupted. Owing to the arrangement of the additional brake, which allows the turbine wheel to be held fast in forward running, the hydrodynamic power-transmitter can be allowed to absorb an amount of power dependent on engine speed at any given time corresponding to a slip of up to 100 % In this connection, power is transmitted by the bridging clutch, as in forward running, by way of the pump to the hydrodynamic power-transmitter, and normal circulatory blading is correctly used in this way The said brake can be engaged in any mechanical speed

bridging the hydrodynamic power-transmitter, so that a hydraulic braking range exists, subdivided in accordance with the number of speeds, allowing the driver to provide very good adaptation to the country over which he is travelling The vehicle can consequently be braked in the various mechanical speeds either by the engine alone, or at choice or in addition hydraulically by actuation of the hydraulic brake acting on the turbine wheel The regulation control programme provided for pure engine braking with limitation of maximum engine speed can be retained without the power absorbed in the hydrodynamic unit reaching unallowably high values. This advantageous action is the more favourable the greater the number of speeds provided in which the drive can be braked by the hydrodynamic unit alone when the same is bridged, or in addition to, the engine. A further feature of the invention consists in that when several driving ranges with automatic speed charge are arrange-d within each driving range, these ranges comprise forward speeds proceeding by -jway of the hydrodynamic power-transmitter and di':-ering from one another More particularly in this connection, if there are trio adjustable driving ranges comprising like speds bidging the hydrodynamic unit, one of the two driving ranges (for example " Normal ") also has a lowr speed proceeding by way of the hydzcdynaiic unit, and the other one of the driving ranges (for example "Hill ") also has a i Glow speedu 9 bridging the hydrodynamic unit and a further and still lower speed proceeding by wa r o the hydrodynamic unit. The use of such a number of speeds bridging the hydrodynamic unit can maize operation considerably less economical As experience has shown, the increase in fuel c Gnsumption caused by the use ox hydrodynamic powertransmitters is undesirably great especially in commercial vehicles Limitation o A operation of such a povver-transmnitter to a single speed per driving range can limit the decrease in efficiency to a minimum, the power-transmitter being used exclusively for starting, and the hydroaynamic system being out of action in the entire remaining driving ranges At the same time, however, the poffer-transmitter can be used for braking the vehicle in all those speeds in 7 wihich it is not connected to the drive, in a manner particularly favourable to the running and safety of the vehicle, and making running more economical. The change-speed gearing preferably comprises two planetary gearings connected in succession, of which the first is connected by a first drive member (for example a sun wheel) to the bridging cutchl, by a second drive member (for example also a sun wvheel), preferably by way of a freewheel, to the turbine wheel of the hydrodynamic unit, and by way of a third drive member (for example a planet carrier) and also,

more particularly for the purpose of attaining a reverse speed, at choice simultaneously by way of a fourth drive (for example an external wheel) to the second planetary gearing In this connection, there is no need for a special planetary set for reverse speed. In all cases, provided the action sought is not bound up with the use of a converter, the 70 latter can be replaced by a hydraulic circuit. Further features and details of the invention can be gathered from the following description of a constructional example which 75 reproduces a particularly simple solution of the principle according to the invention, although the invention is naturally not limited to this constructional eacnpie. In the accompanying skaoing^: 80 Figure 1 is a idiagrammatc reiwrsentation of the drive according o the invention; Figure 2 a part-al section through a freewheel supporting the reactor of the hydrodynamic converter against the housing; 85 Figure 3 a partial section through the freewheel connecting the turbine wheel of the hydrodynamic converter with the changespeed gearing follo 2 izg it; Figure 4 a selection table of the individual 90 speeds, and Figure 5 a tractive and braking force diagram ol the drive. Referring to the dra-wing, drive is effected by the engine shaft 1 G, connecting for example 95 a drum 11, acting simultaneously as a flywheel, to the pump 1 vneel 2 el the Pydroaynamic converter 13 The reactor 14 of the hydrodynamic converter 13 is connected in per se known manner to a supporung ring 16 through 100 thie irezevwheel 15, thie supporting ring being fast vwith the driving gear-clutch Lousing 17. In this connection, tile ireiehecl 15 is so constructed as to be frned in relation to the ring 16 -wzhen the reactor i 4 is driven in the for 105 ward rotational direction x 1, Figure 2, and to couple the ractor to the housing when the reactor is driven in t-ie oi pcsite direction. The turbine wheel 18 is connected on the one hand by a iollow shaft 19 to the internal 110 ring 20 of a further ireewileel 2 i, and on the other hand to the drum 22 of a brake B,. The hollow shaft 19 surrounds a shaft 23 which can be coupled to the engin shiaft 10 and to the pump s;vheel 12 by the clutch K 1 115 arranged to bridge the hydredynamic converter 13 It is also the driving shaft of a first planetary gearing l U,, which consists of the sun wheel 24 connected to the shaft 23, of a further sun wheel 26 looseiir su>;-e tan o th 120 shaft 23 and connected to the c:ternal ring of thet freewheel 21, of the Pianet wheels 28 and 29 supported on the planet carrier 27, and of the external wheel 30 The sun wheel 26 is in this case of smaller diameter than 125 the sun wheel 24 T-li free-vheel 21, as shown more particularly in Figure 3, is so constructed as to drive the external ring 25, and thus the sun wheel

26 in the direction of rotation x, only when drive takes place by the turbine 130 7-05,963 785,963 wheel 18 through the internal ring 20, but to interrupt the drive when the external ring 25 overtakes the internal ring 20. A clutch K 2, accommodated in a spatially favourable arrangement axially between the hydrodynamic converter 13 and the planetary gearing U, on the one hand, and radially between the freewheel 21 and the brake B, on the other hand, can couple the sun wheel 26 to the planet carrier 27, and thus lock the planetary gearing U, in itself. The planet carrier 27 can be braked by a brake B, and the external centre wheel 30 of the planetary gearing U, by a brake B,. The planet carrier 27, by way of a shaft 31, is fast with the outer central wheel 32 of a second planetary gearing U 2 The central wheel 32 drives the planet carrier 34 of the second planetary gearing U 2 by way of the planet pinion 33, and the take-off shaft 35 driving for example the wheels of a motor vehicle through a differential drive The sun wheel 36 of the second planetary gearing is connected to a shaft 38 by way of the drum 37, the shaft being capable of being coupled to the outer central wheel 30 of the first planetary gearing U, by a clutch K, The sun wheel 36 can be braked by a brake B 4 A further clutch K 4 allows the second planetary gearing U, to be locked in itself. The table in Figure 4 shows the selection positions of the clutches and brakes in the individual speeds, the sign o signifying the disengaged position, and the sign + the engaged position of the clutch or brake. As is apparent from the table, the change-speed gearing works with two driving ranges, or winch the " Normal " driving range comprises four forward speeds and one reverse speed, and the " Hill " driving range five forward speeds and one reverse speed. In this connection, the driving range can be set up by a range slide-valve, and the individual speeds can be selected within the driving range by a pressure-step regulator, as described by way of example in the earlier Patent Specification No 740,985. As can be seen from the table, the 2nd to 4th forward speeds and the reverse speed of the " Normal " driving range coincide with the 3rd to 5th forward speeds 'and the reverse speed respectively of the " Hill " driving range. The bridging clutch K, is engaged in the said forward speeds, so that drive takes place exclusively mechanically The bridging clutch K, is disengaged in the reverse speed R, so that drive takes place hydraulically by way of the hydrodynamic converter 13, and thus through the freewheel 21. In addition to these speeds, the " Normal" driving range has a further

hydraulic 1st speed working by way of the hydrodynamic converter, while the " Hill " driving range comprises an additional mechanical 2nd speed and a further additional hydraulic 1st speed of high transmission ratio acting through the hydrodynamic converter. Drive takes place individually in the speeds as follows:"HILL" DRIVING RANGE, 1st SPEED 10, 12, 18, 19, 21, 26 ( 30 braked), 292 28, 27, 31, 32 ( 36 braked), 33, 34, 35. " HILL" DRIVING RANGE, 2nd SPEED 10, K,, 23, 24 ( 30 braked), 28, 27, 31, 32 ( 36 braked), 33, 34, 35. " NORMAL " DRIVING RANGE, 1st SPEED 10, 12, 18, 19, 21, 26 ( 30 braked), 29, 28, 27, 31, U 2 (locked in itself by K 4). "HILL ", 3rd SPEED AND " NORMAL 2nd SPEED 10, K,, 23, 24 ( 30 braked), 28, 27, 31, U 2 (locked in itself by KJ 4), 35. "HILL, 4th SPEED AND " NORMAL 3rd SPEED 10, Kl,, 23, U, (locked in itself by K,), 31, 32 ( 36 braked), 33, 34, 35. "HILL ", 5th SPEED AND " NORMAL ", 4th SPEED 10, K,, 23, U,(locked in itself by K,), 31, U, (locked in itself by K 4), 35. " HILL AND " NORMAL ", REVERSE SPEED 10, 12, 18, 19, 21, 26 ( 27 braked by B,), 29, 28, 30 K,, 38, 37, 36 ( 32 braked by B,), 33, 34, 35. Either B, or K, is engaged in the mechani 95 cal forward speeds If B, is engaged, the sun wheel 26 is driven faster than the sun wheel 24, and thus faster than the pump wheel 12 of the hydrodynamic converter, this causing the freewheel 21 to be uncoupled Such 100 uncoupling by the freewheel 21 also takes place when the planetary gearing U, is locked by the clutch K,, since the interval ring 20 adso rotates in this case at lower peripheral speed than the external ring 25 in the direction x, 105 because of slip in the hydrodynamic converter 13. The brake B, is not normally engaged in any forward or reverse speed If it is engaged in one of the mechanical speeds, i e when the 110 bridging clutch K 1 is engaged, the driving shaft 23 connected to the pump wheel 12 is braked, and thus also the take-off shaft 35 by way of the drive because of the turbine wheel 18 braked by B, The pump wheel 12 115 rotating at the speed in question must then work against the stationary turbine wheel 18 with the hydrodynamic converter at maximum slip, which causes the braking power developed to be dissipated in the hydrodyna 120 mic converter for the purpose of braking the vehicle by way of the speed which happens to be engaged If the pump, wheel 12 is fast with 785,963 the engine driving shaft 10, the braking powers of the engine and the hydrodynamic converter will add in any given case The arrangement of an additional clutch between the clutch K, and the engine shaft, or between the clutch K, and the pump, wheel 12 also makes it possible, if desired, to cut-off the braking action of the engine or of the hydrodynamic converter as required.

The converter brake B, can be engaged in addition in any of the mechanically selected speeds ( 2 to 5 in the " Hill " driving range, 2 to 4 in the " Normal " driving range). A diagram is illustrated by way of example in Figure 5 for the drive working in the "Hill" driving range with five speeds and in the " Normal " driving range with four speeds, in dependence on road speed, tractive force when the engine is driving being plotted in the upper part of the diagram (above the axis of the abscisse), and braking force (for example each in kg) in the lower part of the diagram (below the axis of the abscissa) In this connection, the individual speeds are designated by I to IV for the " Normal " driving range and by F to V' for the " Hill " driving range. In this connection, the tractive force in the "Normal" driving range is indicated by a full line, and in the " Hill " driving range by a dotted line As can be seen a continuously variable tractive force according to the lines I (" Normal ") and I' (" Hill ") is produced on starting with hydraulic transmission, while the tractive force diagram varies in stepped form in the remaining speeds in accordance with the change-speed gearing ratios, which vary in stepped form. The braking force attainable by the converter brake is also indicated in the diagram by the full parabolic lines, while the braking force produced by the engine when it is braking is reproduced approximately by the dotted lines As can be seen therefrom, the braking action produced by the converter brake above any given road speed is greater than the braking action produced by the engine, the braking action of the converter brake increasing rapidly with increasing speed of travel Overloading of the engine by using it for braking the vehicle can consequently be avoided in all circumstances. A geometrical relationship between the speeds of 1:1 6 is assumed in the constructional example in accordance with the table in Figure 4 Any other desired relationships between the speed ratios can naturally also be used. It is to be recalled that the reference to hydrodynamic power-transmission unit in the appended claims are intended to include a hydraulic torque converter and a fluid-coupling as above indicated.


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