US3716903A - Process for assembling a snubbing arrangement in a railway truck - Google Patents

Abstract

A process for assembling a snubbing arrangement in a railway truck where the truck includes a bolster interconnecting a pair of side frames and a pair of friction shoes in inclined bolster pockets at each end of the bolster and cooperating with vertical surfaces in each side frame. The process includes the steps of assembling the friction shoes in the bolster pockets, inserting a torsional spring means in an unstressed condition into the bolster with a central portion engaging the bolster and end portions engaging the friction shoes, inserting the bolster, spring means and friction shoes into the respective side frame, and imparting a constant load on the spring means by urging the central portion away from the bolster so as to urge the friction shoes upwardly into the pockets and outwardly into snubbing engagement with the vertical surfaces of the side frame.

Description

United States Patent 1 Tack [ 1 Feb. 20, 1973 [54] PROCESS FOR ASSEMBLING A SNUBBING ARRANGEMENT IN A RAILWAY TRUCK [75] Inventor: Carl E. Tack, Elmhurst, Ill.

[73] Assignee: Amsted Industries Chicago, 111.

[22] Filed: Jan. 4, 1971 [21] Appl. No.: 103,424

Incorporated,

Related US. Application Data [63] Continuation-impart of Ser. No. 736,420, June 12,

1968, Pat. No. 3,575,117.

2,827,987 3/1958 Williams ..l05/197 D Primary ExaminerCharles W. Lanham Assistant ExaminerV. A. Dipalma Attorney-Walter L. Schlegel, Jr. and Russell W. Pyle [57] ABSTRACT A process for assembling a snubbing arrangement in a railway truck where the truck includes a bolster interconnecting a pair of side frames and a pair of friction shoes in inclined bolster pockets at each end of the bolster and cooperating with vertical surfaces in each side frame. The process includes the steps of assembling the friction shoes in the bolster pockets, inserting a torsional spring means in an unstressed condition into the bolster with a central portion engaging the bolster and end portions engaging the friction shoes, inserting the bolster, spring means and friction shoes into the respective side frame, and imparting a constant load on the spring means by urging the central portion away from the bolster so as to urge the friction shoes upwardly into the pockets and outwardly into snubbing engagement with the vertical surfaces of the side frame.

5 Claims, 5 Drawing Figures a 42 aa\ PATENTED FEBZOIQYS SHEET 10F 2 PATENTEQ Emma SHEET 2 OF 2 c'mx E 71104 fi-nuap Jag/s.

PROCESS FOR ASSEMBLING A SNUBBING ARRANGEMENT IN A RAILWAY TRUCK This is a continuation-in-part of my application Ser. No. 736,420, filed June 12, 1968, now U.S. Pat. No. 3,575,] 17.

This invention relates to snubbing arrangements for railway vehicles and more particularly to a process for assembling a snubbing arrangement utilizing friction shoes operatively carried in wedge-shaped pockets at opposite sides of a truck bolster structure, wherein the friction shoes are urged into sliding frictional contact with wear plates mounted on the vertical columns of the side frames of the truck.

Two primary concepts have developed in the use of a spring force to urge friction shoes into engagement with the side frame columns and other frictionsnubbing surfaces of the truck. One concept involves the application of a spring under compression between the bolster and the friction shoe mounted in the bolster structure. In the usual construction, the friction shoe is borne upwardly against the inclined walls of pockets formed in the bolster and outwardly against the side frame columns, the spring exerting a substantially constant force against the friction shoe regardless of vertical movements of the bolster. The spring may be mounted under compression in a cavity within the friction shoe or in other locations, but space limitations and difficulties of installation have sometimes presented problems in the use of such arrangements.

The other concept involves the application of one or more control springs under compression between a member of the truck side frame and the friction show operatively mounted in the bolster. Since the truck bolster supports the weight of the car body and is resiliently supported in the side frames, the force exerted on the friction shoes is variable and increases as the weight on the bolster increases. Because of space limitations and the tendency of such control springs to take permanent set after use over a period of time, this type of arrangement cannot provide adequate control forces under all conditions of load and normal wear of friction elements.

An object of this invention is to provide a process for assembling a snubbing arrangement in a railway truck utilizing a unique constant torsional spring force that may be used either in conjunction with a variable compression spring force or alone.

Another object of this invention is the provision of a process of assembling a snubbing arrangement including a torsional spring to which an independent torsional load is applied after installation of such spring.

Other objects will become apparent from the following description and appended claims, taken in connection with the accompanying drawings wherein;

FIG. 1 is a fragmentary elevational view, partly in section, of a railway truck that incorporates features of the presently described invention;

FIG. 2 is a fragmentary side view of a portion of the bolster that incorporates features of the present invention;

FIG. 3 is a fragmentary plan view of the bolster shown in FIG. 2;

FIG. 4 is a plan view of the torsional spring utilized in the preferred embodiment of the present invention; and FIG. 5 is an elevational view of the wedge utilized with the torsional spring described herein.

With more particular reference to FIG. 1, the improvements of the present invention are shown embodied in a railway car truck which generally comprises a pair of side frames, one of which 10 is shown, interconnected by a bolster 12 resiliently supported at its ends on spring groups 14. Each side frame 10 includes a top or compression member 16 and a bottom or tension member 18 interconnected by spaced vertical columns 20 which together define an opening to receive the end of the bolster 12.

Inasmuch as the opposite sides of the truck herein shown include identical parts, the drawings and description, for the sake of brevity, will be confined to one side of the truck, it being understood that a complete truck includes like parts at both sides thereof.

As best shown in FIGS. 1-3, the snubbing arrangement generally comprises a pair of wedge-shaped pockets 22 (FIG. 3) formed in opposite sides of the bolster 12 near the end thereof, said pockets opening outwardly toward the side frame columns 20 and having an inclined wall 24. A friction shoe 26 is operatively carried in each pocket 22, and includes an inclined surface 28 corresponding to and frictionally engaging the inclined wall 24 of the pocket, as well as a vertical surface 30 for frictionally engaging vertical wear plates 32 mounted on the side frame columns 20.

As shown in FIG. 1, if a variable spring force on the friction shoes is desired, this maybe accomplished by the use of one or more control springs 34 extending between the friction shoe 26 and a corresponding location on the tension member 18 of the side frame 10. The control spring 34 serves to urge the friction shoe 26 upwardly into wedging engagement between the inclined wall 24 of the bolster pocket 22 and the wear plate 32 on the side frame column 20.

As illustrated in FIGS. 1-4, a constant spring force on the friction shoes is provided by a helical torsional spring 36. As best shown in FIGS. 2-4, this spring includes two separate helical portions 38 arranged around a common horizontal axis and interconnected by a U-shaped portion 40 extending away from said axis. The free ends of the helical portions 38 terminate in respective substantially straight extensions 42, which also extend away from the horizontal axis of the spring. As will be hereinafter more fully explained, the U- shaped portion 40 forms a convenient lever to which a torque may be separately applied for imparting a torsional load to the entire spring, which causes the extensions 42 to act as resilient levers for engaging and urging the friction shoes 26.

As shown in FIGS. l-3, the torsional spring 36 is placed in operative position by first inserting the end extensions thereof 42 through respective elongated vertical slots 44 in the outboard sides of the pockets 22 on both sides of the bolster and into a respective cavity 46 formed within each friction shoe 26. When so inserted, the torsional spring 36 is designed such that the helical and U-shaped portions thereof, 38 and 40, respectively, will lie on the bottom wall 48 of the bolster 12, while the end extensions 42 will be engageable with respective friction shoes 26 within the respective cavities 46 thereof. It will also be noted that the spring is installed in a substantially unstressed condition, thereby greatly facilitating its insertion and removal.

The cavity 46 of the friction shoe 26 is provided with a transverse vertical wall 41 extending from the top of said cavity downwardly for a portion of the height of said cavity and extending between the walls of the inclined surface 28 and the vertical surface 30 of the friction shoe. As shown in FIGS. 1 and 2, the end extensions 42 of the torsional spring 36, when in operative position, are engageable with the lower surface of the transverse vertical wall 41. The transverse vertical wall 41 also serves the useful function of providing additional internal support for the friction shoe 26.

Means are provided for applying a torsional load to the torsional spring 36 after its installation which means may comprise a wedge, generally indicated at 50, which is inserted or driven between the U-shaped portion 40 of said spring and the bolster bottom wall 48 after said spring has been placed in position. As best shown in FIG. 3, the wedge 50 includes a pair of spaced legs 52 that straddle the central vertical web 54 of the bolster. When viewed from the side, as shown in FIG. 5, the wedge 50 may be seen to include an upper inclined portion 56 sloping upwardly to merge with a horizontal portion 58 upon which the U-shaped portion 40 of the torsional spring 36 rests when in assembled position. The wedge 50 also includes a raised head 60 and an upwardly inclined toe 62, which prevent the spring 36 from becoming dislodged during and after assembly. A locking lug 64 may be provided on the bottom of the wedge 50 to engage and lock with a corresponding cavity 66 (FIG. 2) upon assembly of said wedge.

When the wedge 50 is installed, a torque is applied to the U-shaped portion of the torsional spring 36, thereby imparting a torsional load to said spring, which causes the free end extensions thereof 42 to be urged upwardly against the internal transverse vertical wall 41 of each friction shoe 26. A constant force is thereby applied to urge the friction shoe 26 upwardly into wedging engagement between the inclined wall 24 of the bolster pocket 22 and the wear plate 32 of the side frame column 20. It may thus be seen that the torsional spring and wedge arrangement may be used alone or in combination with the variable spring force herein before described.

Assembly of the bolster and friction parts into the side frame is preferably carried out as follows: The friction shoes 26 are first inserted into the bolster pockets 22 and are held therein by insertion of the torsional spring 36, as previously described, in substantially unstressed condition. The end of the bolster 12 is then inserted into the enlarged lower portion of the opening between the side frame columns and is raised upward to allow assembly of the subjacent spring groups 14 and 34. A torsional load is then applied to the torsional spring 36 as hereinbefore described. In its unstressed condition, the assembled torsional spring serves to hold the friction shoes in their respective pockets during assembly of the bolster into the side frames. The truck may be disassembled by reversing the above procedure.

friction surfaces, said bolster having pockets with inclined surfaces to receive friction shoes for snubbing engagement with said friction surfaces, said process comprising positioning unitary spring means in an unstressed condition with a central portion in engagement with said bolster and with end portions in engagement with respective friction shoes, and then imparting a constant load to said spring means by urging the central portion away from said bolster to thereby urge said friction shoes upwardly against the inclined surfaces and outwardly into engagement with the friction surfaces of the side frame.

2. The process according to claim 1 wherein the step of imparting a load to said spring means comprises inserting a wedge between a surface on said bolster and the central portion of said spring means.

3. A process for assembling a snubbing arrangement in a railway truck having a side frame connected to a bolster, one end of said bolster being received in a window defined by an opening between columns of said side frame, said bolster having downwardly opening pockets carrying friction shoes for snubbing engagement with respective side frame columns, said process comprising first assembling the friction shoes in the bolster pockets, holding said friction shoes in said pockets while placing a torsional spring means in unstressed condition with a central position in engagement with said bolster and with end portions in engagement with the respective friction shoes such that the friction shoes are held upward in said pockets, then assembling the bolster, torsion spring means and friction shoes into the window of the side frame, and then applying a constant torsional load to said torsional spring means by urging the central portion thereof away from the bolster in such a manner as to urge said friction shoes into engagement with respective side frame columns.

4. The process according to claim 3 wherein the step of imparting a torsional load to said spring means comprises inserting a wedge between a surface on said bolster and a central lever portion extending from said spring means.

5. In a method of assembling a snubbed railway truck wherein a bolster is spring-supported by a side frame having a friction surface, and wherein a friction shoe engages said friction surface and also engages an opposed wedge surface of the bolster; the steps of engaging the shoe with said surfaces, engaging an actuator spring with said shoe and said bolster with the actuator spring in unstressed condition, and then stressing the actuator spring to urge the shoe against said surfaces by inserting a member between and abutting portions of the spring and the bolster.

Claims (5)

1. A process for assembling a snubbing arrangement in a railway truck having a side frame and a bolster received in an opening of the side frame defined by friction surfaces, said bolster having pockets with inclined surfaces to receive friction shoes for snubbing engagement with said friction surfaces, said process comprising positioning unitary spring means in an unstressed condition with a central portion in engagement with said bolster and with end portions in engagement with respective friction shoes, and then imparting a constant load to said spring means by urging the central portion away from said bolster to thereby urge said friction shoes upwardly against the iNclined surfaces and outwardly into engagement with the friction surfaces of the side frame.

1. A process for assembling a snubbing arrangement in a railway truck having a side frame and a bolster received in an opening of the side frame defined by friction surfaces, said bolster having pockets with inclined surfaces to receive friction shoes for snubbing engagement with said friction surfaces, said process comprising positioning unitary spring means in an unstressed condition with a central portion in engagement with said bolster and with end portions in engagement with respective friction shoes, and then imparting a constant load to said spring means by urging the central portion away from said bolster to thereby urge said friction shoes upwardly against the iNclined surfaces and outwardly into engagement with the friction surfaces of the side frame.

2. The process according to claim 1 wherein the step of imparting a load to said spring means comprises inserting a wedge between a surface on said bolster and the central portion of said spring means.

3. A process for assembling a snubbing arrangement in a railway truck having a side frame connected to a bolster, one end of said bolster being received in a window defined by an opening between columns of said side frame, said bolster having downwardly opening pockets carrying friction shoes for snubbing engagement with respective side frame columns, said process comprising first assembling the friction shoes in the bolster pockets, holding said friction shoes in said pockets while placing a torsional spring means in unstressed condition with a central position in engagement with said bolster and with end portions in engagement with the respective friction shoes such that the friction shoes are held upward in said pockets, then assembling the bolster, torsion spring means and friction shoes into the window of the side frame, and then applying a constant torsional load to said torsional spring means by urging the central portion thereof away from the bolster in such a manner as to urge said friction shoes into engagement with respective side frame columns.

4. The process according to claim 3 wherein the step of imparting a torsional load to said spring means comprises inserting a wedge between a surface on said bolster and a central lever portion extending from said spring means.

Images