US3814266A

US3814266A - Return spring unit for a railway car

Info

Publication number: US3814266A
Application number: US00248890A
Authority: US
Inventors: V Hawthorne
Original assignee: Keystone Industries Inc
Current assignee: Keystone Industries Inc
Priority date: 1972-05-01
Filing date: 1972-05-01
Publication date: 1974-06-04
Anticipated expiration: 1991-06-04

Abstract

A return spring unit for a railway car, which can be installed as new construction or as a replacement, comprises a rod adapted to be secured to a coupler carrying element, a housing adapted to be secured to the car, and a spring guided in the housing and reacting between the rod and housing to return the coupler carrying element to a predetermined longitudinal position. The return spring unit is constructed so that at least the rod or housing is mounted to be movable laterally with respect to the longitudinal axis of the unit, and sufficient clearance is provided between its components to isolate the spring from lateral relative movements, thus reducing rubbing between the spring and housing and reducing spring stresses to provide increased spring life.

Description

[4 June 4, 1974 RETURN SPRING UNIT FOR A RAILWAY CAR 213/8 Zanow ..2l3/40R Zanow..........,.......................213/64 Primary Examiner-Drayton E. Hoffman m ma mp wa u .w E n .ma h uc e VM R m m V n l .M 7 l [73] Assignee: Keystone Industries Inc., Chicago,

Attorney, Agent, or Firml-libben, Noyes & Bicknell [57] ABSTRACT A return spring unit for a railway car, which can be installed as new construction or as a replacement,

' comprises a rod adapted to be secured to a coupler U.S. 213/8, 213/40 R, 213/67,

carrying element, a housing adapted to be secured to the car, and a spring guided in the housing and react- 213/69 B6lg 9/12, B6lg 11/02 213/8, 40 R, 40 D, 40 5 ing between the rod and housing to return the coupler [51] Int. [58] Field of Search carrying element to a predetermined longitudinal position. The return spring unit is constructed so that at least the rod or housing is mounted to be movable laterally with respect to the longitudinal axis of the unit,

[56] References Cited UNITED STATES PATENTS and sufficient clearance is provided between its com- 213 3 ponents to isolate the spring from lateral relative 213/69 movements, thus reducing rubbing between the spring 213/8 and housing and reducing spring stresses to provide 213/8 increased spring life.

213/8 19 Claims, 5 Drawing Figures mmmn nw u o O. u S tr .on m r e.m a.m MLFELS 02634 0093344 00009999 HHHHHH 256265 5695 6 59 6 7002400 326624 248,025}. 222

RETURN SPRING UNIT FOR A RAILWAY CAR This invention relates to a return spring unit for a railway car and more particularly to a return spring unit in which a spring, a guide for the spring and other associated structures can be installed or replaced as a unit in railway cars.

In prior constructions, conventional return springs used in conjunction with cushioning arrangements for railway cars were and are individually installed in the car. These conventional constructions are disadvantageous in that considerable time and skilled manpower is needed to install or replace such a return spring in a new or old car. Also, it is necessary for workmen to compress such spring into a preloaded position during installation and this exposes the workmen to the danger of having the spring accidentally expand.

Further, conventional return springs may be subject to undue stress due to relative movements that may occur between portions of a railway car. For example, in cars having a sliding sill the sliding sill may move in any direction relative to the fixed sill due to normal train operation and track conditions. If such relative movement is lateral and is transferred to the return spring, it can cause increased stresses in the spring and may also cause the spring to rub against adjacent structures. When a spring is guided by a center rod, rubbbing and wear occurs at the more highly stressed inner diameter of a coil type spring. Thus, stresses caused by the lateral relative movements combined with such rubbing may cause the spring to fail.

A return spring unit embodying the present invention is preassembled for easy installation in a car, and comprises a spring, a guide or housing member around the outside of the spring and a central rod member. One of the members is adapted to be secured to a coupler carrying element, and the other member is adapted to be secured to the car. The spring is confined in and guided by the guide or housing member and operatively interconnects the members to force the coupler carrying element toward a predetermined or normal position. Clearance in the radial direction is provided between the various parts of the return spring unit in order to isolate the spring, as much as practicable, from lateral or transverse ralative movements that mayoccur between the members. A pair of longitudinally spaced spring stops are provided on the first member, and another pair of longitudinally spaced spring stops are provided on the second member. The pairs of spaced spring stops cooperate with the ends of the spring so that the spring is compressed upon movement of one member in one direction by a spring stop at one end of the first member against the spring stop at the opposite end of the second member. The spring is compressed upon movement of the one member in the other direction by a spring stop at the other end of the first member against the spring stop at the opposite end of the second member. The spring fits closely within the guide member and is guided thereby on the outer diameter of the spring to prevent buckling of the spring. Thus, if the spring should tend to buckle, only the outer diameter of the spring will touch the guide member and be subject to wear, thus contributing to longer spring life. Also, at least one of the members of the return spring unit is mounted to move any direction laterally in a plane perpendicular to the axis of the spring, that is, one of the members is floatingly mounted. In this way the spring is protected from certain relative movements between the members and unnecessary stresses.

It is a primary object of the present invention to provide a preassembled return spring unit adapted to be installed as a complete assembly, instead of piecemeal.

Another object of the present invention is to provide a return spring unit suitable for use in a railway car, which has its spring protected or isolated from transverse relative movements to increasespring life.

Still another object of the present invention is to provide a return spring unit suitable for use in a railway car, which has a spring guided on its outer diameter.

These and other objects of the present invention will become apparent from the following description taken in conjunction with the accompanying figures of the drawings wherein:

FIG. 1 is a side elevational view of a return spring unit embodying the present invention and installed in a railway car;

FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a view taken along the line 4-4 of FIG. 2 showing the return spring unit displaced to the right; and

FIGJS is a view similar to FIG. 4 but showing the return spring unit displaced to the left.

In FIG. 1 is illustrated a return spring unit of the present invention installed in a railway car having a fixed sill l0 and a sliding sill 12. While the present form of the return spring unit is shown installed in connection with a sliding sill, it should be understood that the return spring unit can be adapted to other types of impact cushioning devices.

The return spring unit, identified generally as 11, is connected between a fixed sill l0 and a sliding sill 12 to return the sliding sill 12 to a predetermined or normal position after longitudinal displacement. As is shown in FIG. 2, the fixed sill comprises a pair of sill channels 24 joined at their upper end by a plate 26. The sliding sill 12 is channel-shaped and is slidably supported in the'fixed sill 10 by conventional means, not shown. Railway couplers, not shown, are attached to the opposite ends of the sliding sill 12 in a conventional manner.

The return spring unit 11 comprises a housing or guide member 18 which, in this instance, is secured to the fixed sill 10, a spring 20 which is contained in the housing member 18, and a rod member 22 which is secured to the other of the sills. The housing, 18 in this instance, comprises a tubular center section 28, for example a ten-inch diameter, schedule 20, pipe having a -ins i s d me er and enair re ans ar9nd pl i at il .31229 h rinalate irsilar s a e p nings 32 of 8-jnch dianieter. The

end plates

30 and 31 form stops forth'e spring. Ea ch ofiliee rid mts'so' or 31 is secured to the end of the tubular section 28 as by welding. Reinforcing gussets 33 may be provided between the

end plates

30 and 31 and the tubular section 28.

The housing member 18 is provided with means for securing it to the fixed sill 10. Thus, the tubular center section 28 is welded at its bottom to a pair of spaced angles 34, and the angles 34, reinforced by several spaced vertical gussets 35, are secured by bolts 39 to a pair of transverse. horizontal cross-channels 36. The present return spring unit is adapted to be mounted in various shaped center sills. For example, the present unit 11 is designed to be mounted either in a relatively shallow sill such as shown in FIG. 2, or in a much deeper sill (not shown). In the latter case, it may not be possible to have the cross-channels 36 secured to the bottom flanges of the sill channels as in FIG. 2, but instead the cross-channels may be secured higher up in the sill between the side walls of the sill channels. To this end, each of the cross-channels 36 has two caps 37, having three holes 38. The, caps 37 are welded to their associated cross-channels 36 in position for attachment to deep fixed sills. Insuch case, the ends of cross-channels 36 are cut off so that the caps 37 form the ends of their cross-channels. The cross-channels 36 can then be bolted, through bolt holes 38, to the center webs of the sill channels. In the case shown in the drawings, however, the channels 36 are bolted to the bottom flanges of the sill channels 24 of the fixed sill by bolts 42 through spacers 44. Thus, the housing member 18 is rigidly secured to the car and in particular to the fixed sill 10.

As can be seen in FIG. 1, the rodmember 22 extends through both ends of the housing member 18. A pair of washer-like spring stops 40 and 41 are welded to the rod member 22, one being at each end of the housing member 18. THe rod spring stops 40 and 41 are positioned on the rod to generally align with the

end plates

30 and 31 of the housing and are sized so that the rod spring stops 40 and 41 can pass through the openings 32 in the end plates, the rod spring stops 40 and 41 being of 5-inch diameter and the openings 32 being of 8-inch diameter.

j The spring is generally concentric with the housing member 18 and the rod member 22. The spring 20 is spaced only a small diastance away from the housing member but is spaced a greater distance away from the rod member and is located between the

rod spring stops

40 and 41. Thus, the spring, if it should shift its position or buckle, will not touch the rod membenbut will touch, if at all, only the housing member 18. Accordingly, rubbing and wear will be confined to the outer surface of the spring 20 adjacent the housing. The spring 20 is also located and confined between the pair of end plates or stops and 31 of the housing member 18. In the present embodiment, when in its normal position. the rod stops and 41 are spaced slightly further apart than the

end plates

30 and 31, and the spring is somewhat compressed between the

end plates

30 and 31. Thus, the rod member 22 is free to move or float as is hereinafter described. The tubular section 28 of the housing 18 serves as a guide to prevent the spring 20 from buckling when it is further compressed during operation. Normally spring stresses on the outside diameter of the spring are less than on the inside diameter of the spring, and the bearing area of the spring and tubular section 28 is sliding contact is larger then if the spring were guided on its inside diameter, further contributing to long spring life. Consequently, this construction offers the advantage of increased spring life. and. further, the housing 18 protects the spring 20 from dirt. the housing 18 protects the spring 20 from dirt.

At each end of the spring 20, between the ends thereof and the

adjacent end plates

30 and 31, is a follower plate or 51. Each

follower plate

50 or 51 comprises an outer circular disk portion 53 and an inner center hub 54. The hub 54 has an opening 56 somewhat larger than the diameter of the rod member 22 and serves to guide its associated

follower plate

50 and 51 on the rod. In this instance, the hub 54 is formed of q s uleeir M1 222 i-i h in diametqaz l le thprqdritabet s 1-'1 -a2.;..b-depletes providing one-eighth-inch clearance between the hub 54 and rod member 22. The diameter of the circular disk portions 53 of

plates

50 and 51 is larger than the diameter of the openings 32 in the

adjacent end plates

30 and 31 so that each follower plate, when in the position shown in FIG. 1, can only move inwardly away from its adjacent end plate and cannot move outwardly through the opening in the end plate. In this instance, the diameter of the

plates

50 and 51 is lO%-inches, while the openings 32 are 8 inches in diameter. A oneeighth-inch clearance is provided between the

follower plates

50 and 51 and the tubular section 28.

The left-hand end of the rod member 22 as shown in FIG. 1, is adapted to be secured to the sliding sill 12. The left-hand end of the rod member 22 has clamp means in the form of a pair of rectangular stop plates 60 each having upper and lower reinforcement bars 62 secured thereto to prevent the plates from buckling under load. The stop plates 60 are clamped to or engage stops 64 (FIG. 4) secured, as by welding, to the side walls of the channel forming the sliding sill 12. The two stop plates 60 are joined by four bolts 66 and are held tightly against the ends of the stops 64 on the sliding sill. Each of the stop plates 60 has an elongated vertical slot 68, having l /z-inch upper and lower radii and a 2 /z-inch length between the centers of the radii to permit the rod member 22 to move freely therein. As is shown in FIG. 1, a stop washer 7,0 is welded to the rod member 22 to the right of the stop plates 60, and the left end of the rod member is threaded, as indicated at 72, and receives a washer 73, alocking typenut 74 and a cotter pin 76, the cotter pin being provided as an added safety measure to prevent the nut from coming off. The nut and thread have 4 /2 threads per inch pitch, and the nut 74 is not screwed tightly in place but is backed off one turn from its tight position to permit the rod member 22 to move or float-with respect to the stop plates 60 in a vertical and, to a lesser extent, also a horizontal direction transverse to the longitudinal sills. Thus, if one of the sills should move in a transverse direction with respect to the other sill, the rod member 22 floats and isolates the spring 20 and the housing 18 from such relative movement. This construction reduces stresses on the spring 20 and reduces rubbing between the spring and tubular section 28 to increase spring life.

Installation of the return spring unit in the railway car is easily accomplished since the entire unit is installed as an assembly, the individual components thereof having been previously assembled at the factory. The unit has the added safety feature of having its spring confined in the housing member 18, and need not be compressed into position in the car, a practice which could lead to injury. In the form of the invention illustrated in the drawings, the unit need only be placed in the sill with the stop plates 60 on either side of the sliding sill stops 64. The bolts 66 are then tightened to mount the rod member 22 to the sliding sill 12. The bolts 66 and threaded portion 72 of the rod member 22 are of sufficient length to accommodate various size stops 64. The

housing member 18 is also easily secured in place merely by bolting the cross-channels 36 to the fixed sill 10.

Operation of the return spring unit of the present invention is shown in FIGS. 1, 4 and 5. The return spring unit is shown in a normal position in FIG. 1 and is capable of displacement in either direction from the normal position to cushion buff or draft impacts at either end of the car.

In FIG. 4, the car is shown with the sliding sill 12 displaced to the right as would be caused by either a buff impact imposed on the left end of that sill, or a draft impact imposed on the right end of that sill. When the sliding sill 12 has moved to the right it carries the rod member 22 also to the right relative to the fixed sill and member 18. As can be seen in FIG. 4, the righthand end of the rod member 22 including the right rod spring stop 41 has passed through the opening 32 in end plate 31. The rod spring stop 40 has pulled the follower plate 50 to the right and compressed the spring against the follower plate 51 and the end plate 31 of the housing. The energy thus stored in the spring 20 will eventually restore the movable parts of the return spring assembly and sill 12 to their normal position.

The return spring unit in FIG. 5 is shown displaced as if the sliding sill 12 had been subjected to a draft impact at the left end or buff impact at the right end of the sliding sill. Under such conditions, the sliding sill 12 moves to the left and takes the rod member 22 with it relative to the housing member 18 and fixed sill 10. As is shown in FIG. 5, the lefthand rod spring stop 40 has moved through the opening 32 in the end plate while the rod stop 41 has engaged the follower 51 and compressed the spring 20 against the end plate 30 of the housing 18. When the spring expands, it will return the movable parts of the return spring unit and sill 12 to their normal positions.

From the foregoing it is apparent that a return spring unit according to the present invention is easily and safely installed in a railway car. The return spring unit has increased spring life because at least one of its members is floatingly mounted relative to the other to isolate the spring from unwanted transverse relative movements, and the spring is guided on its outside diameter and protected by its housing.

I claim:

l. A return spring unit for installation as a unitary assembly in a railway car having a fixed element and a movable coupler carrying element with stop means, said unitary assembly comprising a rod member adapted to be connected to the coupler carrying element, a tubular member adapted to be connected to the fixed element, said rod member extending into said tubular member, said rod member having means adajcent one end for releasably connecting said rod member to the stop means on said coupler carrying element, the other end of said rod member being free and normally adjacent an end of said tubular member, and a spring contained within and guided by said tubular member to prevent buckling of said spring during compression thereof, said rod the tubular members each having spring stop means for engaging both ends of said spring to operatively connect said rod and tubular members, when the coupler carrying element moves in one direction said spring stop means at one end of said rod member compresses said spring against said spring stop means of said tubular member at the opposite end of said spring and said other end of said rod member moves away from said tubular member, when the coupler carrying element moves in the other direction said spring stop means at the other end of said rod member compresses said spring against said spring stop means of said tubular member at the opposite end of said spring and said other end of said rod member moves into said tubular member, whereby said rod and tubular members are forced by said spring to return to a relative normal position with said other end of said rod member adjacent said end of said tubular member.

2. A return spring unit as in claim 1, wherein said railway car has a fixed sill and a sliding sill, said coupler carrying element comprising said sliding sill and said fixed element comprising said fixed sill.

3. A return spring unit as in claim 2, wherein said rod member has a pair of spaced washers secured thereto forming said spring stop means and said tubular member has a pair of end plates secured thereto forming said spring stop means.

4. A return spring unit as in claim 1, wherein at least one of said rod and tubular members is floatingly connected to its associated element to isolate said spring from relative lateral movement of said elements in a plane transverse to the longitudinal axis of the railway car.

5. A return spring unit as in claim 4, wherein said rod member is floatingly connected to said coupler carrying element of said car.

6. A return spring unit for a railway car having a fixed element and a movable coupler carrying element, comprising a rod member adapted to be secured to one of the elements, a tubular housing member adapted to be secured to the other of the elements, and a spring contained within said tubular housing member, said spring being guided on its outer surface by the inner surface of said tubular housing member to prevent buckling of said spring during compression thereof, said rod member having a pair of spaced spring stops for engaging the ends of said spring, said tubular housing having and end plate at each end forming a spring stop cooperable with the ends of said spring, said end plates having openings therein and said rod member extending through said openings, said spring encircling but being spaced from said rod member and being located between said spring stops on said rod member and between said end plates of Said tubular housing member, when the coupler carrying element moves in one direction said spring is compressedbetween said spring stop at one end of said rod member and said end plate of said tubular housing member at the opposite end of said spring, when the coupler carrying element moves in the other direction said spring is compressed between said spring stop at the other end of said rod member and said end plate of said tubular housing member at the opposite end of said spring, whereby said rod member and said tubular housing member are forced by said spring to return to their relative normal positions. I

7. A return spring unit as in claim 6, further comprising a pair of followers, one follower being located at each end of said spring, each end of said spring being in contact with one side of the adjacent follower, at least one spring stop on said rod member and at least one end plate of said tubular housing member being in contact with the other sides of said followers, said followers being larger than said openings in said tubular housing member, said spring stops on said rod member being smaller than said openings in said tubular housing member.

8. A return spring unit as in claim 7, wherein said followers further comprise hubs having inner openings, said hubs being slidably mounted on saidrod member and said inner openings of said hubs being larger than the outer dimension of said rod member, said outer dimensions of said followers being less than the inner dimension of said tubular housing member.

9. A return spring unit as in claim 6, wherein said rod member includes clamp means at one end adapted to be secured to various width stops.

10. A return spring unit as in claim 9, wherein said clamp means comprises a pair of stop plates and fastening means for said stop plates, said stop plates each have a slot therein, said slot having a length and width larger than that of said rod member, said rod member extending into said slots and being loosely held on said rod member by said fastening means, whereby said rod member is floatingly secured to said stop plates.

11. A return spring unit for installation as a unitary assembly in a railway car having a fixed element and movable coupler carrying element, comprising a rod member having a pair of spaced apart spring stops thereon, a tubular housing member having end plates with openings therein, a coil spring located in said tubular housing member, and a pair of followers one at each-end of said spring within said tubular housing member, said followers having openings therein and being slidably mounted on said rod member, said spring being guided by said tubular housing member and spaced away from said rod member, said openings in said follower members being smaller than said spring stops on said rod member, said spring stops on said rod member being smaller than and passing through said openings in said end plates, said followers being larger than said openings in said end plates, whereby said spring forces said followers against said spring stops on said rod member and against said end plates to force said members toward a predetermined relative positron.

12. A return spring unit as in claim 11, wherein said railway car has fixed and sliding sills, one of said rod and tubular housing members being secured to said fixed sill of said railway car, the other of said rod and tubular housing members being secured to said sliding sill of said railway car.

13. A return spring unit as in claim 12, wherein one of said rod and tubular housing members is floatingly secured to its associated sill to isolate said spring from transverse relative movements between said sills.

14. A return spring unit as in claim 13, wherein said rod member includes a threaded end, a stop washer intermediate said threaded end and said spring stop means, a pair of slidable stop plates, bolt means and a nut, said stop plates engaging opposite ends of stop means on said sliding sill, said bolt means holding said stop plates in tight engagement with said stop means, said stop plates having anopening'therein larger than said rod member, said nut and stop washer loosely holding said stop plates on said rod member, whereby said rod member is floatingly secured to said sill.

15. A return spring unit for installation in a railway car having a fixed sill and a sliding sill, comprising a rod member adapted to be operatively connected to one of the sills, a tubular member adapted to be operatively connected to the other of the sills, said rod and tubular members having spring stops, a spring operatively cooperating with said spring stops on said rod and tubular members to cushion longitudinal movements of said sills, and floating connection means for one of said members for providing a floating connection between its associated sill and said spring to isolate said spring from transverse relative movements between said sills, said floating connection means comprising one portion fixed in position relative to said associated sill and another portion mounted on said one member, said other portion being relatively slidable with respect to said one portion in a plane substantially perpendicular to the longitudinal axes of the sills in both vertical and horizontal directions. I

16. A return spring unit as in claim 15, wherein said oneportion is adapted tobe mountedon said sliding sill.

17. A return spring unit as in claim 16, wherein said other portion is mounted on said rod member.

18. A return spring unit as in claim 17, wherein said one portion comprises slotted stop means adapted to be fixedly secured to said sliding sill, said other portion on said rod member loosely securing said rod member to said slotted stop means.

19. A return spring unit for installation in a railway car having a fixed sill and a sliding sill, comprising a first member adapted to be operatively connected to said fixed sill, a second member adapted to be operatively connected to said sliding sill, a spring operatively cooperating with said first and second members to connect said sills to cushion longitudinal movements of said sills, and floating connection means for providing a floating connection between said sliding sill and said spring to isolate said spring from transverse relative movements between said sills, said floating connection means including stops adapted to be fixedly secured to said sliding sill, a pair of plates each having a vertical slot therein, and bolt means for securing said plates to said stops on said sliding sill, said second member extending through said slots of said loosely secured thereto.

plates and being-

Claims

1. A return spring unit for installation as a unitary assembly in a railway car having a fixed element and a movable coupler carrying element with stop means, said unitary assembly comprising a rod member adapted to be connected to the coupler carrying element, a tubular member adapted to be connected to the fixed element, said rod member extending into said tubular member, said rod member having means adajcent one end for releasably connecting said rod member to the stop means on said coupler carrying element, the other end of said rod member being free and normally adjacent an end of said tubular member, and a spring contained within and guided by said tubular member to prevent buckling of said spring during compression thereof, said rod the tubular members each having spring stop means for engaging both ends of said spring to operatively connect said rod and tubular members, when the coupler carrying element moves in one direction said spring stop means at one end of said rod member compresses said spring against said spring stop means of said tubular member at the opposite end of said spring and said other end of said rod member moves away from said tubular member, when the coupler carrying element moves in the other direction said spring stop means at the other end of said rod member compresses said spring against said spring stop means of said tubular member at the opposite end of said spring and said other end of said rod member moves into said tubular member, whereby said rod and tubular members are forced by said spring to return to a relative normal position with said other end of said rod member adjacent said end of said tubular member.

6. A return spring unit for a railway car having a fixed element and a movable coupler carrying element, comprising a rod member adapted to be secured to one of the elements, a tubular housing member adapted to be secured to the other of the elements, and a spring contained within said tubular housing member, said spring being guided on its outer surface by the inner surface of said tubular housing member to prevent buckling of said spring during compression thereof, said rod member having a pair of spaced spring stops for engaging the ends of said spring, said tubular housing having and end plate at each end forming a spring stop cooperable with the ends of said spring, said end plates having openings therein and said rod member extending through said openings, said spring encircling but being spaced from said rod member and being located between said spring stops on said rod member and between said end plates of said tubular housing member, when the coupler carrying element moves in one direction said spring is compressed between said spring stop at one end of said rod member and said end plate of said tubular housing member at the opposite end of said spring, when the coupler carrying element moves in the other direction said spring is compressed between said spring stop at the other end of said rod member and said end plate of said tubular housing member at the opposite end of said spring, whereby said rod member and said tubular housing member are forced by said spring to return to their relative normal positions.

8. A return spring unit as in claim 7, wherein said followers further comprise hubs having inner openings, said hubs being slidably mounted on said rod member and said inner openings of said hubs being larger than the outer dimension of said rod member, said outer dimensions of said followers being less than the inner dimension of said tubular housing member.

11. A return spring unit for installation as a unitary assembly in a railway car having a fixed element and movable coupler carrying element, comprising a rod member having a pair of spaced apart spring stops thereon, a tubular housing member having end plates with openings therein, a coil spring located in said tubular housing member, and a pair of followers one at each end of said spring within said tubular housing member, said followers having openings therein and being slidably mounted on said rod member, said spring being guided by said tubular housing member and spaced away from said rod member, said openings in said fOllower members being smaller than said spring stops on said rod member, said spring stops on said rod member being smaller than and passing through said openings in said end plates, said followers being larger than said openings in said end plates, whereby said spring forces said followers against said spring stops on said rod member and against said end plates to force said members toward a predetermined relative position.

14. A return spring unit as in claim 13, wherein said rod member includes a threaded end, a stop washer intermediate said threaded end and said spring stop means, a pair of slidable stop plates, bolt means and a nut, said stop plates engaging opposite ends of stop means on said sliding sill, said bolt means holding said stop plates in tight engagement with said stop means, said stop plates having an opening therein larger than said rod member, said nut and stop washer loosely holding said stop plates on said rod member, whereby said rod member is floatingly secured to said sill.

15. A return spring unit for installation in a railway car having a fixed sill and a sliding sill, comprising a rod member adapted to be operatively connected to one of the sills, a tubular member adapted to be operatively connected to the other of the sills, said rod and tubular members having spring stops, a spring operatively cooperating with said spring stops on said rod and tubular members to cushion longitudinal movements of said sills, and floating connection means for one of said members for providing a floating connection between its associated sill and said spring to isolate said spring from transverse relative movements between said sills, said floating connection means comprising one portion fixed in position relative to said associated sill and another portion mounted on said one member, said other portion being relatively slidable with respect to said one portion in a plane substantially perpendicular to the longitudinal axes of the sills in both vertical and horizontal directions.

16. A return spring unit as in claim 15, wherein said one portion is adapted to be mounted on said sliding sill.

19. A return spring unit for installation in a railway car having a fixed sill and a sliding sill, comprising a first member adapted to be operatively connected to said fixed sill, a second member adapted to be operatively connected to said sliding sill, a spring operatively cooperating with said first and second members to connect said sills to cushion longitudinal movements of said sills, and floating connection means for providing a floating connection between said sliding sill and said spring to isolate said spring from transverse relative movements between said sills, said floating connection means including stops adapted to be fixedly secured to said sliding sill, a pair of plates each having a vertical slot therein, and bolt means for securing said plates to said stops on said sliding sill, said second member extending through said slots of said plates and being loosely secured thereto.