US3712479A

US3712479A - Rubber-hydraulic draft gear for railway cars

Info

Publication number: US3712479A
Application number: US00202175A
Authority: US
Inventors: E Atkinson
Original assignee: ACF Industries Inc
Current assignee: Cooper Industries LLC
Priority date: 1971-11-26
Filing date: 1971-11-26
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23
Also published as: DE2238270A1; CA954076A; FR2162841A5; GB1413809A

Abstract

A draft gear for a railway car includes a first rubber draft gear having a movable pre-load plate at its forward end acted on by the coupler shank, and a second rubber draft gear having a front pre-load plate in contact with a rear follower plate of the first draft gear. A hydraulic cushion is fixed to the second draft gear and is in abutment with rear stops so that neither the hydraulic cushion or the second draft gear are movable bodily. The hydraulic cushion has a piston with valved buff and draft orifices and is fixed to a shaft which extends forwardly through the second draft gear into abutment with the rear follower plate of the first draft gear. Another portion of the shaft extends rearwardly into abutment with a yoke fastened to the coupler shank. The two draft gears and the hydraulic cushion act in the buff direction, but only the hydraulic cushion and the first draft gear act in the draft direction.

Description

iJnited States Patent 1191 1 1 3,712,479 Atkinson 1 'Jan. 23, 1973 RUBBER-HYDRAULIC DRAFT GEAR FOR RAILWAY CARS Field inventor:

Assignee:

Filed:

Appl. No.:

EulasR. Atkinson, Conroe, Tex.

ACF Industries, Incorporated, New York, N.Y.

Nov. 26, 1971 US. Cl. ..213/47, 213/8, 213/45,

1111. C1 ..B6lg 9/08 of Search ..2l3/8, 43, 45, 46, 47', V 267/64 R, 65 R, 35; 188/312, 317

7 References Cited UNITED STATES PATENTS DRAFT TRAVEL BUFF TRAVEL PrimaryExaminer-Drayton E. Hoffman Attorney-Eugene N. Riddle [57] ABSTRACT A draft gear for a railway car includes a first rubber draft gear having a movable pre-load plate at its forward end acted on by the coupler shank, and a second rubber draft gear having a front pre-load plate in contact with a rear follower plate of the first draft gear. A hydraulic cushion is fixed to the second draft gear and is in abutment with rear stops so that neither the hydraulic cushion or the second draft gear are movable bodily. The hydraulic cushion has a piston with valved buff and draft orifices andis fixed to a shaft which extends forwardly through the second draft gear 11 Claims, 4 Drawing Figures BUFF TRAVEL PATENTEUJAHZB I975 3.712.479

SHEET 1 0F 2 ATTORNEY PATENTEDJAN 23 1973 SHEET 2 [1F 2 FIG. 4.

I RUBBER-HYDRAULIC DRAFT GEAR FOR RAILWAY CARS BACKGROUND OF THE INVENTION ing impacts in the draft direction, the hydraulic draft gear and the first rubber draft gear act in parallel.

SUMMARY OF THE INVENTION A shock absorber for a railway car is suitably mounted in an end or center sill of the car and consists of a first rubber draft gear, a second rubber gear, and a hydraulic draft gear arranged serially between the'coupier shank and a set of stops in the sill. When a buff force is applied to the coupler, the coupler shank moves the forward end of the first draft gear through a predetermined distance before compressing the second draft gear. Further buff force causes contraction of the second draft gear which is pre-loaded more heavily than the first draft gear, and at the same time movesthe piston of the hydraulic draft gear. After' a limited travel, the second rubber draft gear closes and no further buff travel is possible. The draft gear yoke engages a'shaft extending rearwardly from the piston. When a draft force is applied to-the coupler, the yoke moves the piston forwardly. During such movement of the yoke, a biased check valve in the piston is opened to provide a small orifice. A shaft portion extending forwardly from the piston acts on a rear follower plate of the first draft gear to compress the first draft gear and thereby by provide additional cushioning. The rubber draft gears tend to restore the pistonto an intermediate position after a buff or"draft travel stroke.

BRIEF DESCRIPTION OF THE DRAWING FIG. -,l is an endview of the hydraulic draft gear 7 DESCRIPTION OF THE PREFERRED EMBODIMENT For the sake'of simplicity, only somuchof the railway carstructure'is herein disclosed as is necessary for a full understanding of Ithe'invention. The draft gears constituting the invention are shown mounted in an end or center sill including sides 10 and II, a top plate 12 and a bottom cover plate l3, and provided with a striker plate 14 and rear stops l6. Coupler 18 has a shank 20 connected by pin 22 to yoke 24. .Opening" 25 in shank 20 which receives pin 22 has an insert 26 therein with an arcuate surface, and insert 26 may move relative to shank 20. Surfaces 28 defining opening 25 are tapered and permit movement of the coupler in-the horizontal and vertical directions. A rear portion 30 of coupler shank 20 is adapted to engage follower block. 32 which acts on pre-load plate 34 of rubber draft gear 36. Follower block 32 abuts draft stops 33 and has guides 35 secure thereto. Gear 36 is therefore capable of being compressed in buff as well as in draft until plate 34 engages projections 38 of draft gear housing 40. Draft gear housing40 of draft gear 36 is in abutment with pre-load plate 42 of rubber draft gear 44 so that draft gear 44 can be compressed in buff until plate 42strikes stop 46. Draft gears 36 and. 44 are provided with

pre-loading bolts

48 and 50 normally holding these draft gears under predetermined compressions. Bolts 48 are relatively short bolts and are threaded in secured relation to pre-load plate 42. Bolts 50 are relatively long bolts which extend through suitable openings in pre-load plate 42 and have their ends threaded and secured to pre-load plate 34. It is noted as shown particularly in FIG. 1 that long bolts 50 are diagonally mounted on opposite sides of both

draft gears

36 and 44. Short bolts 48 are diagonally mounted on opposite sides of only draft gear 44.

An outer housing generally indicated 52 forms an end cap 53 of hydraulic draft gear 56 and extends therefrom about

draft gears

36 and 44 tostops 33. The hydraulic draft gear includes cylinder 60 fastened by bolts 58 to end'cap 53 and'piston' 62 connected to a shaft having a forward portion 64 and rear portion 66. Piston 62 is provided with spring-pressed ball check valve 68 to open a draft orifice 70 and spring-pressed ball check valve 72 providing buff orifice 74. Draft orifice 70 is made very small in order to give a greater wardly, along with yoke 24. Thus, yoke 24 is spaced from shaft 66 in the buff position as shown in FIG. 4. Upon the occurrence of a draft force applied to the coupler, yoke 24 is pulled forwardly moving shaft 66 and piston 62 forwardly causing shaft 64 to slide through plate 42 and act on rear plate 40 of cushion 36 to compress the latter. The pre-load or compression force of cushion 36 is smaller than that of cushion 44.

When ver'ysmall buff forces occur, only draft gear 36 is compressed, thus reducing wear of the hydraulic draft gear. I 7

As an example, total buff travel may be around four inches while total draft travel may. be 1 around two inches. First draft gear 36 may be pre compressed to a load of 4,000 pounds and second draft gear 44 may be pre-compressed to a load of l0,000 pounds. Upon a buff force exerted against the railway car, rubber draft gear 36 is compressed until a certain force level is reached at which time draft gear 44 ispre-compressed in parallel with first draft'gear 36. Cushioned travelof hydraulic draft gear 56 is simultaneous with the cushionedtravel of rubber'draft gear 44 as pre-load plate 42 abuts shaft portion 64. Draftgear 36 then bottoms out against projections 38 and draft gear 44 continues its travel along with hydraulic draft gear 56 until abutting stops 46.

Various features and advantages of the invention may be noted. The rubber draft gears act as springs tending to return piston 62 to its normal position in cylinder 60. The available draft travel is the distance between plate 34 and projection 38; i.e., the movement required to close draft gear 36. The buff travel limit is equal to the travel required to close draft gear 36 plus the distance between plate 42 and stop 46. Upon reaching the travel limit in either direction, positive solid stops prevent further movement; thus protecting hydraulic draft gear 56 against forceful bottoming. lmmediately after a full buff or draft stoke, hydraulic cushioning travel in the opposite direction over the full length of cylinder 60 is available. Another advantage of the system is that both the draft and buff force-travel characteristics of the hydraulic draft gear can be made optimum by the separate draft and buff fluid orifices 70 and 74 in the piston. For example, in one embodiment of the invention, the area of the draft orifice was made one-tenth the area of the buff orifice. Another important advantage is that the cushioning forces of draft gears 36 and 44, which increase rapidly as the cushion travel increases, compensate the hydraulic cushion force, which decreases rapidly after reaching an initial peak; thus maintaining high values of cushioning forces through nearly the entire hydraulic cushion travel, and

providing a large cushioning capacity for draft and buff, with most of the impact energy being dissipated.

What is claimed is:

1. Railway car cushioning apparatus comprising first and second rubber draft gears and a hydraulic draft gear arranged serially at one end of the car underframe; a car coupler having a shank; a draft gear yoke connected to the coupler shank and enveloping all three draft gears, said hydraulic draft gear including a movable member having a portion extending outward slidably through the second rubber draft gear and into abutment with the inner side of the first rubber draft gear; and means for causing a buff force applied to the coupler to compress the first and second rubber draft gears and to be applied through the first draft gear to the movable member of the hydraulic draft gear to actuate the same; and means for only actuating the hydraulic draft gear and the first rubber draft gear in response to a draft force applied to the coupler.

2. Apparatus according to claim 1, wherein said hydraulic draft gear includes a fluid-containing cylinder and a movable piston therein having a shaft extending through the cylinder to the first rubber draft gear, and stop means for preventing movement of the cylinder and the inner side of the second rubber draft gear.

3. Apparatus according to claim 2, wherein said rubber draft gears include means for setting said piston at an intermediate position in said cylinder in the absence of buff or draft forces.

4. Apparatus according to claim 3, wherein said shaft also extends rearwardly from said piston into engagement with said yoke.

5. Apparatus according to claim 4, wherein said piston includes a check valve adapted to open in response to buff forces and another check valve adapted to open in response to draft forces.

6. Apparatus according to claim 1, wherein said hydraulic draft gear includes a stationary cylinder and a piston therein normally positioned at an intermediate point thereof and adap e to move in the buff and draft directions.

7. Apparatus according to claim 6, wherein said piston includes a check valve adapted to open in response to draft forces, and a check valve adapted to open in response to buff forces.

8. Apparatus according to claim 6, including a shaft having one portion extending from said piston into abutment with the first rubber draft gear and another portion extending from said piston rearwardly to said yoke.

9. Railway car cushioning apparatus comprising first and second resilient draft gears and a hydraulic draft gear arranged serially at an end of the car; a car coupler having a shank; a draft gear yoke connected to the coupler shank and enveloping all three draft gears, said hydraulic draft gear including a movable piston having a portion of a shaft extending forwardly freely through the second draft gear and into abutment with the inner side of the first draft gear; and another portion of the shaft extending rearwardly into abutment with said yoke; and means for causing a buff force on the coupler to compress said first draft gear and to be applied through the first draft gear to the second draft gear and to the shaft of the hydraulic draft gear to actuate the same; and means for actuating only the hydraulic draft gear and the first rubber draft gear in response to a draft force applied to the coupler.

10. Railway car cushioning apparatus comprising first and second rubber draft gears and a hydraulic draft gear arranged serially in an end sill portion of the car; a car coupler having a shank; a draft gear yoke connected to the coupler shank and enveloping all three draft gears; a movable plate structure at the outer face of the first rubber draft gear; draft stop means for the first draft gear, the inner end of said coupler shank being closely juxtaposed to said movable plate structure for moving it in the buff direction, said hydraulic draft gear including a piston having a shaft extending slidably through the second rubber draft gear and into abutment with the inner side of the first draft gear, said first draft gear having a lower compression force characteristic than that of said second draft gear, whereby said first rubber draft gear is initially actuated and the second rubber draft gear and the hydraulic draft gear are then actuated in unison in response to a buff force and only the hydraulic draft gear and first rubber draft gear are actuated in response to a draft force.

11. Apparatus according to claim 10, wherein said piston has a check valve adapted to be opened by predetermined buff force and another check valve adapted to be opened by a predetermined draft force, said check valves thereby providing metering orifices from one side of the piston to the other side thereof.

Claims

6. Apparatus according to claim 1, wherein said hydraulic draft gear includes a stationary cylinder and a piston therein normally positioned at an intermediate point thereof and adapted to move in the buff and draft directions.