US3520421A - Coupler positioning arrangement for railway vehicles - Google Patents

Description

July 14, 1970 J. E. GUTRIDGE 3,520,421

COUPLER POSITIONING ARRANGEMENT FOR RAILWAY VEHICLES Filed June 5, 1966. 3 Sheets-Sheet 1 INVENTOR JACK E GUTR/DGE LC Maw RC 26 NC ATT'Y.

July 14, 1970 J. E. GUTRIDGE 3,520,421

COUPLER POSITIONING ARRANGEMENT FOR RAILWAY VEHICLES Filed June :5, 1966 3 Sheets-Sheet 2 INVEN TOR JACK E. GUTR/DG 5W? J- E. GUTRIDGE July 14, 1970 COUPLER POSITIONING ARRANGEMENT FOR RAILWAY VEHICLES Filed June 5, 1966 3 Sheets-Sheet 3 INVENTOR JACK E. GUTRIDGE United States Patent 3,520,421 COUPLER POSITIONING ARRANGEMENT FOR RAILWAY VEHICLES Jack E. Gutridge, Dyer, Ind., assignor to Pullman Incorporated, Chicago, Ill., a corporation of Delaware Filed June 3, 1966, Ser. No. 555,652 Int. Cl. B61g /00, 7/12 US. Cl. 213 3 Claims ABSTRACT OF THE DISCLOSURE A railway car includes a hydraulic coupler positioning arrangement which accurately positions the coupler horizontally when cars are coupled together on a curved track. The arrangement includes a fluid pressure responsive means disposed between the coupler and frame for swinging the coupler laterally. A fluid motor means is connected between the railway car truck and the frame for sensing the curvature of the track and actuates the fluid pressure responsive means for swinging said coupler when uncoupled to a position wherein said coupler is substantially centered with respect to the underlying track.

The present invention relates to railway vehicles and more particularly to an arrangement for positioning the coupler means mounted on the ends of said vehicles to a selective angle relative to the longitudinal axis of the vehicle.

Railway cars are currently being constructed with a greater distance between the coupler and the adjacent trucks. These greater distances are required in the construction of long travel cushion underframe cars having a cushion travel of about to 40 inches and in the construction of long cars in excess of 75 feet. In the long travel cushion underframe car the sliding sill on which the coupler is to be attached must extend outwardly of the ends of the car at least a distance commensurate with the length of travel. Accordingly, the coupler would be displaced outwardly of the trucks a greater distance than in a conventionally uncushioned car frame construction.

In the cars of lengths exceeding about 75 feet the maximum distance between truck centers is required to be about 70 or less feet in order to negotiate the curves of existing trackage over which the railway car travels. Under these conditions it is, of course, evident that any car constructed in excess of the distance of the truck centers will create a greater distance between the couplers and the truck. This distance between the trucks and couplers will hereinafter, for the purpose of simplification be identified as the overhang.

This lengthened overhang has resulted in a problem of centering of the couplers for connection to another car. This is particularly true when it is desired to couple cars on a curve which frequently occurs on a siding or the like. Moreover, some difficulty may be incurred in coupling cars of a conventional length having a conventional overhang with a car of lengthened overhang.

It is a principal object of the present invention to provide a railway car with a coupler positioning arrangement which serves to automatically position the coupler for alignment with a coupler on an adjacent car so as to permit coupling of the two cars without bypassing couplers.

It is a further object to provide a coupler positioning ararngement of the type designated above which is associated with the truck bolster so as to sense the radius of curvature of the track and position the coupler parallel or tangent to the radius of curvature whereby the coupler is aligned to permit coupling without bypassing.

It is another object taken in conjunction with the immediately foregoing object to provide a manually operable arrangement which serves to selectively position the coupler independently of the automatic positioning means.

The coupler positioning arrangement of the present invention comprises generally a motor means which is connected to the railway car in a manner to sense the angular position of the wheels or the radius of curvature of the track on which the wheels are mounted. The motor means includes means for sensing the position and creating a signal. This signal is transmitted to a fluid pressure responsive means fixed to the car and to the coupler. The fluid pressure responsive means is operative upon receipt of the signal to change or swing the swingably mounted coupler to a position corresponding to the center line of the trackage. More specifically, the signal created by the motor means corresponds to the misalignment of the coupler with respect to the center line of the track and this misalignment is corrected by the fluid pressure responsive means which swings the coupler to a position substantially parallel to the center line of the guided path. Accordingly, the coupler will be aligned so as to be in a position for coupling to an adjacent car having the coupler similarly aligned with the center line of the track.

Further objects and features will hereinafter appear.

In the drawings:

FIG. 1 is a schematic view of one end of a car showing the general arrangement of the coupler positioning arrangement of the present invention;

FIG. 2 is a further embodiment of the coupling arrangement of the present invention;

FIG. 3 is an enlarged cross sectional view of the motor valve shown in FIG. 2; and

FIG. 4 is a diagrammatic view showing the manner in which the couplers are positioned prior to coupling to adjacent cars on different curvatures of tracking.

Referring now to FIG. 1, there is schematically illustrated one end of a ralway car 10 embodying the coupler positioning arrangement 11 of the present invention. The railway car 10 may be of the cushion underframe type including a center sill 12 on which there is mounted a sliding sill 13. The sliding sill 13 is movable lengthwise of the center sill 12 to the extent of the travel of the cushioning device (not shown).

Supporting the center sill 12 is a truck 14 including a truck bolster 15 turnably supported for movement about a center plate 16 which is fixed to the underside of a body bolster (not shown) in the conventional manner. The truck further includes a pair of transversely spaced side frames 17 between which there extends an axle 18 carrying the usual wheels 19. A similar wheel and axle assembly 18-19 may be carried on the opposite side of the truck bolster 15.

Mounted in the bell mouth end 21 of the sliding sill 13 is a coupler 22 including a shank 23 pivotally connected to a conventional draft gear (not shown) by Way of a coupler pin 24. At the other end the coupler 22 is formed with coupler head 26 having the usual coupling mechanism. The coupler 22 is laterally swingable about the pin 24 within the limits dictated by the sides of the bell mouth opening 21 of the sliding sill. It is to be noted that the coupler 22 and the coupler head in particular extends a considerable distance from the end of the center sill 12 and the truck 14. Thus, there is a large or increased overhang from the coupler to the truck. This large or lengthened overhang as heretofore mentioned causes a problem in respect to coupling cars together.

Referring now to FIG. 4, there is illustrated a siding including a track T which is formed to have a straight section connected to a section having a relatively small radius of curvature. When a car A is located on the track section of relatively small radius of curvature and is to be. coupled to acar B lying on the straight section, it is to.

be noted that the coupler heads 26 on the car A lie outside of the track T and are not parallel or aligned with the center line of the track as is the coupler head 26 on the car B. This situation creates a problem in coupling the two cars A and B together in the usual manner by way of humping or the like. It would first be necessary to move the coupler head 26 on the car A into alignment with the coupler head 26 on the car B to avoid passed couplers. Manual positioning of the couplers by the use of a crowbar or the like is extremely dangerous. In accordance with the present invention, the coupler positioning arrangement 11 is utilized to automatically maintain the coupler head 26 in longitudinal alignment with the center line of the track so as to permit coupling with the coupler of car B.

The coupler positioning arrangement 11 comprises generally a motor or motive means 27 for sensing the radius of curvature of the track and the deviation of the center line C of the coupler from the center line of the track and generates a signal corresponding to this deviation. Associated with the motor means 27 are fluid responsive members 28 which are associated with the coupler and swing the coupler through an angle corresponding to the signal sensed to a position in alignment with the center line of the radius of curvature of the track.

In the embodiment as shown in FIG. 1 the motor or motive means 27 comprises a fluid motor 29 in the form of a hydraulic filled cylinder including a reciprocal piston head 31 having connected to one face thereof one end of a piston rod 32. The other end of the piston rod 32 is pivotally connected to a pivot bracket 33 fixed to the underframe or center sill 12 or the railway car. The pivotal connection is accomplished by means of a pivot pin 34. At the other end the motor cylinder has fixed thereto one end of a mounting rod 36 of which the other end is formed with a clevis 37 through which there extends a pin 38 supported by way of transversely spaced bracket plates 3939 fixed to the truck bolster 15.

Connected to a port 41 on one side of the piston head 31 and communicating with a chamber 35 is a conduit 42 of which the other end is connected to a port 43 formed in one end of a cylinder 44 of a fluid displacement compensating device 45. On the other side of a piston head 31 and communicating with a chamber 40 is a conduit 46 which is connected at one end to a port 47 in the cylinder 29 and at its other end to a port 43 formed in one end of a cylinder 49 of a second fluid displacernent compensating device 51. Disposed within the cylinders 44 and 49 are reciprocal piston head members 52. The piston head members 52 are of similar construction each comprising an upper plate 53 and a longitudinally spaced lower plate 54. Disposed between the upper and lower plates 53 and 54 is a compression spring 56 which serves to expand and contract under pressure force more and less than that required to move the coupler 22, as more fully to be explained hereinafter.

Connected to a port 57 provided in the opposite end of the cylinder 44 is one end of a conduit 58 of which the other end is connected into an inlet port 59 of a two way valve 61. A second conduit 62 is connected at one end to a port 63 of -the cylinder 49 and at the other end to a port 64 of a two-way valve 66. In the full line position illustrated in FIG. 1 passageways 67 and 68 in the two- way valves 61 and 66, respectively, provide communication between the ports 59 and a port 69, and ports 64 and a port 71, respectively. Connected to the port 69 Is one end of a conduit 72 of which the other end is connected to one end of a cylinder 73 of a fluid responsive means 74. Connected to the port 71 of the two-way valve 66 is one end of a conduit 76 of which the other end is connected to a port 77 in the opposite end of the cylinder 73. Disposed within the cylinder 73 is a reciprocal piston head 78 having a piston rod 79. Fixed to a face of the piston head 78 is one end of a piston rod 79 of which the other end is attached to the shank 23 of the coupler 22. The attachment may be accomplished-by way of a C-clamp connection 81 or the like.

-*The piston head 78 is disposed in the cylinder 73 substantially intermediate the end walls thereof in the neutral position of the coupler as shown in FIG. 1 and defines two chambers 82 and 83. In connection with the foregoing described arrangement, it is to be noted that there are two separate hydraulic circuits and of which the circuit 70 comprises the fluid motor chamber 35, conduit 42, fluid force transmitting device 45, conduit 58, the two-way valve passageway 67, conduit 72 and chamber 82. The other hydraulic circuit 75 includes the fluid motor chamber 40, conduit 46, fluid force transmitting device 51, conduit 62, the two-way valve passage 68, conduit 76 and chamber 83. The circuits 70 and 75 are each charged with fluid under pressure to yield an equal total pressure force in each of the chambers 82 and 83 capable of turning the coupler 22 about the coupler pin 24.

Assuming that the truck 14 of the railway car 10 is traversing or located on a straight portion of the track, the truck bolster 15 will lie transverse to the track T and a center line X extending through the longitudinal axis of the pin 24 and through the center of the center plate 16 in a neutral position, as shown in FIG. 1. In the neutral position the piston head 31 is located substantially midway between the ends of the cylinder 29, as are the piston heads 52 and in the force transmitting devices 45 and 51, and the piston head 78 in the cylinder 74. Thus, the longitudinal axis C of coupler 22 lies along the center line of the straight section of track T-T.

Assuming now that the truck 14 of the railway car is located on the small radius of curvature, as shown, the truck bolster 15 would turn about the center plate 16 toward the center line designated R in FIG. 1. Upon such turning movement, the piston head 31 and the cylinder 29 move relatively to each other so that fluid in the chamber 40 is displaced outwardly through conduit 46 into the force transmitting device 49 so as to displace the piston head 53 disposed therein and force fluid outwardly through the port 63 into conduit 62 through the passage 68 and conduit 76 into the chamber 83 of the cylinder 74. This causes the piston head 78 disposed within the cylinder 74 to move to the left as viewed in FIG. 1. Upon such movement, the piston rod 79 connected to the coupler 22 is operative to move the latter toward the center line designated RC. Such movement of the coupler 22 is possible because the pressure forces on the piston head, as heretofore described, are adequate to move the weight of the coupler components. Upon movement of the piston head 78 to the left, fluid is forced outwardly through the conduit 72 through the two-way passage 67 into the conduit 58 to move the piston head assembly 53 in the device 45 to force fluid through conduit 42 upwardly thereby into the chamber 35 of the cylinder 29. When the forces on both sides of the piston head 31 are equalized the system remains stationary.

Should the truck 14 turn in the opposite direction so that the center line X moves in the direction of the position designated L, flow of the fluid would be in the opposite direction through the circuit 70 and thence through the circuit 75. From the foregoing it should be readily apparent that the motor means 29 is operative to sense the position of the truck 14 and thereby the radius of curvature of the track on which the truck is located so as to transmit a signal and generate a motive power through the cylinder 74 to position the coupler 22 into alignment with the center line of the track T.

During normal train operation when the car 10, having the coupler positioning arrangement aforedescribed, is connected in a line of cars, there may be conditions in which the coupler 22 is held in an angular position opposing that dictated by the angular position of the trucks. This condition would tend to create opposing forces in the system causing failure thereof or under some conditions derailment of the car. In accordance with the present invention such failure or derailment is eliminated by the provision of the piston head assemblies 52 in the fluid pressure transmitting devices 45 and 51.

As heretofore described, the total pressure forces in each of the chambers 82 and 83 is such as to be capable of moving the weight of the coupler about the coupler pin 24 upon movement of the piston head. However, should for example the coupler 22 be held pivoted to the right position RC and the truck be turning to the left so that the center line X assumes the position L, the piston head 31 in the fluid motor means 29 is displaced toward the port 47 to discharge fluid under pressure into the hydraulic circuit 75. At the same time the piston head 78 of the fluid responsive means 74 is displaced toward the port 77, also to discharge the displaced fluid into the hydraulic circuit 75. At the same time the piston head 78 the hydraulic circuit 75 will create pressure forces in the system exceeding the pressure force reuqired to move the coupler 22. It is also to be noted that the chamber 35 of the motor cylinder 29 and the chamber 82 of the fluid responsive valve 74 increase in volume so that there is a corresponding reduction in the pressure forces in the hydraulic circuit 70.

To compensate for these increased pressure forces and fluid volume in the hydraulic circuit 75 and the decreased pressure forces and fluid volume in the hydraulic circuit 70, the compression springs 56 of the piston members 52 are selected so as to expand and contract respectively under these conditions. To this end the springs 56 disposed between the plates 53 and 54 of each of the fluid displacement means is selected so that the total pressure forces in the cylinder acting on the plates during normal operation of the coupler positioning arrangement 11 to compress the spring from the free length thereof to the static length. Hence, upon an increase or decrease in pressure on either or both of the plates 53 and 54, the spring 56 further contracts or expands to increase or decrease the volume of the cylinders 44 and 49 an amount suflicient to maintain the pressure forces within each of the hydraulic circuits 70 and 75 within tolerable limits. In this manner the piston heads 52 act as an overload arrangement.

Reverting now again to the exemplary condition, when the truck 14 is turned to the left and the coupler 22 is held to the right; under these conditions the pressure forces in the fluid displacement compensating means 51 of the hydraulic circuit 75 are increased by the increase in volume of the hydraulic fluid displaced by the opposing action of the piston heads 31 and 78. Thus, the corresponding increase in the pressure forces acting on the plates 53 and 54 cause the spring 56 to be compressed from the static length condition thereof and to increase the volume available within the cylinder 49. As the volume is increased, the pressure, of course, is correspondingly increased to a value within tolerable limits permitting movement of the truck 14 and the coupler 22 independently of each other.

At the same time the increase in volume of the chamber 35 and 82 results in a decrease in the pressure forces on the plates 53 and 54 of the fluid displacement compensating means 45 so that the spring 56 expands and decreases the volume wtihin the cylinder 44. This causes the hydraulic fluid to remain within the cylinder chambers 35 and 82 and thereby prevents the formation of a partial vacuum thereon.

When the opposing condition of the coupler 22 and truck 14 is relieved so that both are turning in the same position, the piston assemblies 52 of the fluid displacement compensating devices 45 and 51 return to the normal position illustrated. As heretofore described, the pressure forces acting on both sides of the piston head 78 of the fluid responsive device 74 are in equilibrium and at a value capable of moving the coupler 22 about the coupler pin 24.

Upon turning movement of the truck 14 and a corresponding displacement of hydraulic fluid through the hydraulic circuits as heretofore described, the piston units 52 in each of fluid displacement compensating devices 45 and 51 remain in the preloaded static length positions shown. This, of course, follows because there are no opposing forces created in either one of the hydraulic circuits 70 and 75.

Under some circumstances it may be desired to manually position the coupler 22. To this end there is incorporated into each of the hydraulic circuits 70 and 75 hand pump circuits and 86, respectively, which serve to override the signal and motive power of motor device 29. As shown the hand pump circuit 85 includes a conduit 87 connected at one end to a port 88 of the two-way valve 61 and at its other end to an inlet port 89 of a hand pump 91 having a manually operable piston 92. Connected to an outlet port 93 is one end of a conduit 94 of which the other end is connected to communicate with the conduit 72 which communicates with the chamber 82 by way of port 71 of the fluid responsive device 74. A pressure relief valve is connected between the conduits 94 and 87.

The hand pump circuit 86 is of similar construction including a conduit 96 connected between a port 97 of the two-way valve 66 and an inlet port 98 of a hand pump 99 having a manually operable piston 101. Connected between an outlet port 103 and the conduit 104 communicating with the chamber 83 is a conduit 104. A pressure relief valve 106 is located between the conduit 96 and 104.

Assuming now that the truck 14 is located on a straight section of track and it is desired to position the coupler 22 toward the position RC, the two-way valve 61 of the hydraulic circuit 70 is rotated so that the passageway 67 provides communication between the ports 59 and 88. This provides fluid communication to the hand or force pump 91 which is actuated to increase the gage pressure in the conduit 94 and accordingly in the chamber 82 of the fluid responsive device 74. This causes an increase on the pressure forces on the piston head 78 thereby moving the latter to the right to swing the coupler connected thereto by the piston rod 79 about the coupler pin 24 toward the position LC, as shown in FIGS. 1 and 2.

It is to he noted that during the operation of the hand pump 91, the piston head 31 in the motor device 29 remains stationary while the piston head 78 of the fluid responsive device moves to the right. This increases the fluid volume in the fluid volume compensating device 51, whereupon there is a corresponding increase in the opposing pressure forces acting on the plates 53 and 54 of the piston assemblies 52. As heretofore described, upon the increase in the pressure forces the compression spring 56 is further compressed to provide a greater volume within the cylinder 49 and thereby maintain the pressure forces in the motor unit 29 at a magnitude below that causing damage to the unit or tending to derail the truck 14 from the tracks T.

Should then the coupler 22 be moved to the extreme limit LC and strike the side of the bell mouth, further pumping of the hand pump 91 would further increase the pressure forces and tend to cause damage. To obviate such damage the relief valve 100 opens so that no pressure increases occur upon further pumping.

The operation for moving the coupler to the left by way of manual pump system 99 is similar to that described above in connection with the manual operation to the left so that a detailed description thereof is not deemed to be necessary.

Referring now to FIGS. 2 and 3, there is shown a further embodiment of a coupler positioning arrangement 200 employing a new and novel fluid motor device 201 in which there is incorporated a fluid displacement compensating piston head assembly 202.

In the following description like element-s and components used in embodiment of FIG. 1 will be designated the same. The coupler positioning arrangement 200 comprises essentially the fluid motor 201, which is connectable with the fluid responsive means 74 through hydraulic circuits 203 and 204 of which one circuit includes a conduit 206, the two-way valve 61, conduit 72 and the hand pump circuit 85. The other hydraulic circuit 204 includes a conduit 207, two-way valve 66, conduit 76 and hand pump circuit 86.

As shown in FIG. 3, the motor device 201 includes a cylinder 208 having an intermediate chamber 209 and two opposing hydraulic fluid containing chambers 211 and 212. Disposed within the chamber 209 is the fluid displacement piston head assembly 202 including a hollow piston head 213 sealingly slidable within the fluid containing chamber 211 having a port 210 to which there is connected one end of the conduit 206. At the open end thereof, the piston head 213, as shown, abuts against one side of a retainer plate 214.

The retainer plate 214 is slidably mounted on a reduced end 215 of a piston rod 216. Holding the retainer plate 214 on the rod is a nut 205. Abutting against the inner face of the retainer plate 214 is one end of a compression spring 217 of which the other end abuts against an opposing inner face of a second retainer plate 218 which is also slidably mounted on the reduced end 215 of the piston rod 216. The compression spring 217 is precompressed to its static length so as to hold the retainer plate 218 against the shoulder 219 formed on the piston rod 216 and the retainer plate 214 against the stop nut 205.

Slidably mounted on an enlarged end of the piston rod is a piston head 222 which abuts at one end to the outer face of the retainer plate 219. The piston head 222 is further disposed for reciprocation within the hydraulic fluid chamber 212 which is formed with a port 223 to which there is connected one end of the conduit 207.

In the embodiment as shown the cylinder has fixed to one end thereof an attachment plate 224 having an opening 226 which receives a pivot pin 227 carried by bracket means 228 fixed to the truck bolster 15. The piston rod 216 at its outer end is formed with an opening 229 which receives a pivot stud 231 supported in a pair of transversely spaced brackets 232 fixed to underframe center sill 12. Thus, upon turning movement of the truck bolster from the neutral position N to either the L or R position, as dictated by the curvature of the rails TT, the piston rod moves relative to the cylinder 208 so that fluid displacement occurs within the chambers 211 and 212, as more fully to be explained hereinafter.

The hydraulic circuits 203, including the motor device chamber 211 and fluid responsive device chamber 82 and the hydraulic circuit 204 including the motor device chamber 212 and fluid responsive device chamber 83 are each charged to a gage pressure yielding pressure forces acting on the opposing faces of fluid responsive piston head 78 which are capable of turning the coupler 22 about the coupler pin 24 and a pressure force on the piston heads 213 and 222 which is substantially equal to the force required to hold the compression spring 217 compressed in its static length. In the neutral position NC of the coupler 22 as shown, the pressure forces acting on the piston head 78 are in equilibrium.

Assuming now that the truck 14 is on the curved section of track TT as shown in FIG. 4, in this position the center line X extending from the center of the center plate 16 through the pivot stud 228 will lie in position R. Ths causes relative movement of the cylinder 208 and the piston rod 216 thereby moving the piston head assembly 202 so that the piston head 222 displaces hydraulic fluid from the chamber 212 outwardly and through the conduit 207 into the passage 68 of the two-way valve 66 and conduit 76, and to the chamber 83 of the fluid responsive device 74. This causes the piston head 78 to be moved to the left whereupon the coupler 22 connected to the piston rod 65 is also moved to the position RC. At the same time hydraulic fluid is discharged from the chamber 82 into the conduit 72 via the port 71, through the passageway 67 of the two-way valve 61 and the conduit 206 and thence into the chamber 211 to hold the piston head 213 in abutting engagement with the retainer plate 214.

During the movement of the cylinder 208 and piston rod 216 and the flow of the hydraulic fluid, the pressure forces acting on the piston heads 213 and 222 are such that the compression spring 217 remains substantially in its static compressed position. However, should a condition arise wherein the coupler 22 is held in the position LC and the truck 14 is turned to the R position, opposing volumes are discharged into the hydraulic circuit 204 so that there is a corresponding increase in gage pressure.

The increase in gage pressure of the respective hydraulic circuits 204, of course, creates a corresponding increase of the pressure forces acting on the piston head 222. The greater pressure forces acting on the piston head 222 slides the latter outwardly of the end wall of the chamber 212 so that the spring 217 is compressed beyond the static length thereof providing a greater volume in the chamber 212. In this manner, the pressure forces within the hydraulic forces are reduced to a magnitude permitting independent movement of the coupler 22 and truck 14.

Of course, during the increase in the pressure gage pressure in the hydraulic circuit 204 there is also a drop in the gage pressure in the hydraulic circuit 203. During this drop the piston head under the influence of atmospheric pressure to which the intermediate chamber 209 is vented by openings 210, moves to the left so that hydraulic fluid remains within the expanded chamber 82 of the fluid responsive device 74.

During operation of the hand pump circuits 85 or 86, the fluid volume compensating device 202 operates similarly to the manner described above. Assuming that it is desired to move the coupler 22 independently of the position of the truck 14 from the position NC to the position LC, the two-Way valve 61 is set so that the passageway 67 is aligned with the ports 88 and 59. Thereafter, the hand piston 92 is actuated to increase the gage pressure in the chamber 82 which communicates with the hand pump via line 94.

The increase in gage pressure causes the piston head 78 to be moved to the right and consequently moving the coupler 22 to the right. This causes hydraulic fluid to be displaced from the chamber 83 into the chamber 212 of the motor device 201 via the conduit 76, passageway 68 and conduit 207. At the same time the operation of the hand pump 91 has caused a reduction in the volume and accordingly pressure in the chamber 211 which communicates therewith via the conduit 206 and passageway 67. Such reduction of volume may be compensated by the movement of the piston head 213 under the forces exerted by the air pressure within the cylinder 208.

The increase in the pressure forces in the chamber 212 creates a corresponding pressure force on the piston head 219 so that the compression spring 217 is compressed providing a greater volume in the chamber 212 and thereby maintaining the gage pressure within tolerable limits. Should the hand pump 91 be operated when the coupler 22 is in its extreme limit position LC, the relief valve will be operative so as to preclude further pressure increases.

Movement of the coupler in the opposite direction is accomplished by means of the hand pump circuit 86 in a manner similar to that described above in connection with the movement to the right.

What is claimed is:

1. A coupler centering device for centering an uncoupled coupler means swingably mounted on the frame of a railway vehicle having a wheeled truck traveling on track, said coupler centering device comprising, a fluid pressure responsive means disposed between said coupler and frame for swinging said coupler laterally relative to the longitudinal axis of said vehicle, a fluid motor means, means providing fluid communication between said fluid motor means and said fluid pressure responsive means, said fluid motor means being disposed between said wheeled truck and said frame to sense the curvature of said track as said truck turns on said track relative to the longitudinal axis of said vehicle and to generate a fluid pressure change in said fluid motor means which corresponds to the angular position of said truck relative to said longitudinal axis of said vehicle so that said fluid pressure responsive means responds thereto and swings said coupler, when uncoupled, to a position wherein the head of said coupler is substantially centered with respect to the underlying track.

2. The invention as defined in claim 1 wherein said fluid motor means comprises a first cylinder and reciprocable piston assembly fixed between said frame and said truck, said fluid pressure responsive means comprises a second cylinder and reciprocable piston assembly, said second assembly being connected to said coupler means and being responsive to a change in pressure caused by relative movement of said first assembly to move said coupler means to a position in alignment with said track, said means providing communication between said first and second assemblies comprising first and second independent hydraulic circuit means connected on opposite sides of said first and second assemblies, said circuit means includes overload means yieldable under opposing pressure forces in said fluid responsive means and said motor means so as to permit overriding of said motor means when said truck and said coupler means are turned in opposite directions, a hydraulic pump including pump actuating means, conduit means connected to said pump, valve means connected to said conduit means movable to a position providing communication of said pump and conduit means with said circuit means whereby during actuation of said pump said second assembly swings said coupler means to selective angular positions independently of said first assembly.

3. The invention as defined in claim 2 wherein said pump actuating means includes manual means for actuating said pump.

References Cited UNITED STATES PATENTS 546,441 9/1895 Vogt 9284 560,918 5/1896 Oderman 9284 1,054,417 2/1913 Hutchinson 92-84 X 1,162,562 11/1915 Brown 92-85 X 1,231,619 7/1917 Krakan 21316 1,273,059 7/1918 Hild 188-98 3,349,926 10/1967 Cope 21320 DRAYTON E. HOFFMAN, Primary Examiner US. Cl. X.R. 21316, 20

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