US 3575117 A
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Description (OCR text may contain errors)
United States Patent- Carl E. Tack Elmhurst, Ill.
June 12, 1968 Apr. 13, 1971 Amsted Industries Incorporated Chicago, Ill.
lnventor Appl. No. Filed Patented Assignee RAILWAY TRUCK BOLSTER SNUBBER 13 Claims, 5 Drawing Figs.
US. Cl 105/197, 105/193, 267/3, 267/4 Int. Cl B611 3/08, B6lf 5/06, B6lf 5/12 Field of Search 105/197,
197 (D), 197 (DB), 193,267/3, 4
References Cited UNITED STATES PATENTS 9/1936 Goodwin 105/197(D) 6/1948 Lehrman... 105/197(D) 2/1954 Spenner 105/l97(DB) 6/1956 Heater et al. 105/197(D) 3/1958 Williams lO5/l97(D) 12/1960 Ingram et al l05/308(P) Primary Examiner-Arthur L. La Point Assistant Examiner-l-loward Beltran Att0meysWalter L. Schlegel, Jr. and Russell W. Pyle ABSTRACT: A helical torsional spring is utilized to urge the friction shoes of a snubbing arrangement upwardly into the inclined bolster pockets in which the shoes are carried. A wedge between the bolster bottom wall and a U-shaped central portion of the spring is used to apply a torsional load on the spring.
Patnted April 13, 1971 2 Sheets-Sheet 1 Zwenfm Carl Z. Y-ZwL Patented April 13, 1971 2 Sheets-Sheet 2 I u/e 1 LZUY- c'a. A? 'IL'LCL a 4 RAILWAY 'II'RIUCII BOILS'IIER SNIJBBER This invention relates to snubbing arrangements for railway vehicles and more particularly to 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 friction-snubbing 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 applicationof one or more control springs under compression between a member of the truck side frame and the friction shoe 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.
Accordingly, an object of this invention is to insure adequate damping through the complete range of car load and normal wear conditions by incorporating a constant force to provide sufficient damping of an empty or lightly loaded vehicle, along with a variable force to add damping for a range of loaded vehicle conditions.
Another object of this invention is to provide a snubbing arrangement utilizing a unique constant torsional spring force that may be used either in conjunction with a variable compression spring force or alone.
A further object of this invention is the provision of a snubbing arrangement including a torsional spring to which an independent torsional load may be 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. I is a fragmentary elevational view, partly in section, of a railway truclt 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. l, 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 16 is shown, interconnected by a bolster I2 resiliently supported at its ends on spring groups 114. Each side frame 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 ll2.
Inasmuch as the opposite sides of the truclt 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 may be 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 It). 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. ll4, a constant spring force on the friction shoes is provided by a helical torsional spring 36. As best shown in FIGS. 24, 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, 33 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 53 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 30 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. lt 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.
1. In a railway car truck including side frames interconnected by a bolster the combination of friction shoe means carried by said bolster for frictional contact with said side frames, and preloaded torsional spring means for applying a constant force to said friction shoe means and urging said friction shoe means into frictional contact with said side frames, said torsional spring means being carried by said bolster and including an arm engaging said friction shoe means.
2. The invention according to claim 1 wherein means are provided for applying a constant torsional load to said torsional spring means.
3. The invention according to claim 1 wherein said torsional spring means further comprises a pair of spaced helical coil portions positioned horizontally on said bolster and interconnected by a U-shaped portion and extensions from said helical coil portions engageable with said friction shoe means.
4. The invention according to claim 3 wherein wedge means is applied between the bolster and the U-shaped portion of said torsional spring means for imparting a torsional load thereto.
5. In conjunction with a railway car truck including a bolster resiliently supported between spaced side frames between spaced vertical columns thereof, said bolster including pockets on both sides thereof and friction shoes carried in said pockets wedgingly interposed between said pockets and said side frame columns, spring means for urging said friction shoe means between said pockets and said side frame columns, said spring means comprising compression spring means subjacent each friction shoe and extending between said shoe and a member of the side frame, and torsional spring means positioned on said bolster, said torsional spring means having extensions engaging said friction shoes, and means for supplying a torsional load to said torsional spring means.
6. In conjunction with a railway car truck including a bolster resiliently supported near its ends between vertical columns of side frames wherein the bolster includes a pocket having an inclined wall adjacent each side frame column and a friction shoe carried by each pocket including an inclined surface corresponding to the inclined wall of the bolster pocket and a vertical surface in sliding frictional engagement with said side frame columns, means for urging the friction shoes on both sides of said bolster upwardly into wedging engagement between the inclined walls of said bolster pockets and said side frame columns, said means comprising a spring horizontally positioned near the end of said bolster on the bottom wall thereof, said spring including two separate helical coil portions having a common horizontal axis and interconnected by a U-shaped portion, said U-shaped portion extending inboard within said bolster and away from said axis, said spring also including a substantially straight extension from each helical coil portion thereof for engagement with respective friction shoes, a cavity in each friction shoe for engagement by respective straight extensions, an elongated vertical slot in each bolster pocket for admitting said straight extensions, and means for applying torque to the U-shaped portion of said spring in such a direction as to urge both friction shoes simultaneously upwardly.
7. The invention according to claim 6 wherein said lastmentioned means comprises a wedge driven between said bolster bottom wall and theU-shaped portion of said spring.
8. The invention according to claim 7 wherein said wedge includes an upper inclined surface merging with a substantially horizontal surface for retaining said U-shaped portion, a raised head and toe portion to prevent accidental dislodgement of said wedge, and a locking lug on the bottom of said wedge engageable with a recess in said bolster bottom wall.
9. The invention according to claim 6 wherein a wall is provided within the cavity of each friction shoe between the walls of the inclined and vertical friction surfaces thereof, said wall extending from the top of said cavity downwardly for a portion of the height thereof.
10. The invention according to claim 6 wherein each side frame includes a compression and tension member, and wherein at least one compression spring is provided subjacent each shoe between said shoe and said tension member.
11. A railway car truck comprising a side frame having tension and compression members, and spaced columns extending between said members to define therewith a bolster opening, a bolster structure resiliently supported from said frame in said opening, said structure comprising a bottom wall and spaced wedge walls diverging upwardly from said bottom wall toward respective columns, friction means on said columns, friction shoe means for engaging respective wedge walls and related friction means, a pair of substantially coaxial coil springs having their axes parallel with said bottom wall and engageable therewith, remote ends of said springs being engaged with downwardly facing surfaces of respective friction shoe means, and wedge means between said bottom wall and the inner ends of said coil springs for urging said inner ends upwardly thereby developing torsional forces in said springs to urge said friction shoe means against respective wedge walls and friction means.
12. A railway car truck according to claim 11 wherein compression spring means are interposed between each friction shoe means and said tension member.
13. In a railway car truck including a side frame, a bolster structure supported on springs in said side frame, and friction wedge means carried by said bolster construction for frictional contact with corresponding locations on said side frames; means for urging said friction wedge means into such frictional contact comprising spring means between the bolster and said friction wedge means for providing a constant force to said friction wedge means and means between said side frame and said friction wedge means for providing an additional, variable force to said friction wedge means.