US3024743A - Self-aligning friction shoe for railway car stabilized trucks - Google Patents

Description

March 13, 1962 c, w s T 3,024,743

SELF-ALIGNING FRICTION SHOE FOR RAILWAY CAR STABILIZED TRUCKS Filed Dec. 5, 1960 2 Sheets-Sheet l I NVENTORS. fi f QZ/(Zanw W @mm C/zseza,

March 13, 1962 R. c. WILLIAMS ETAL 3,0 4,

SELF-ALIGNING FRICTION SHOE FOR RAILWAY CAR STABILIZED TRUCKS Filed Dec. 5, 1960 2 Sheets-Sheet 2 INVENTORS.

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United States Patent 3,024,743 SELF-ALIGNING FRICTION SHOE FOR RAILWAY CAR STABILIZED TRUCKS Ray C. Williams and Claus J. Werner Clasen, Chicago,

Ill., assignors to Standard Car Truck Company, Chicago, Ill., a corporation of New Jersey Filed Dec. 5, 1960, Ser. No. 73,657 4 Claims. (Cl. 105197) The present invention is directed to improvements in railway car stabilized trucks of the general class wherein the vertical oscillations of the truck bolster are damped by means of friction shoes housed in the bolster or in the side frames of the truck and pressed into sliding frictional contact with opposed portions of the bolster or side frames by means of actuating springs operating in conjunction with co-engaged wedging surfaces on the shoes and the housing, respectively.

In railway car trucks of the above general class, the side frames are caused to recurrently rock about the bolster, in a simulated galloping movement, by the individual bouncing of the forward and rear wheels of a truck as they pass, at moderate speeds, over the rail joints, crossovers, or other abrupt variations in the level of the railway track. Inasmuch as the bolster of a car truck oscillates in a fixed vertical plane, the above mentioned recurrent rocking movements of the side frames vary their angularity relative to the bolster and thus vary the angularity of the friction shoes at their frictional interface with said opposed portions of the bolster or side frame, as the case may be.

By virtue of the recurrent changes in angularity of the friction shoes, their upper and/or lower edges are moved away from their interface contact with the opposing member of the truck and consequently reduce the effective frictional area of the shoes. This change in angularity of the side frames also brings about high pressure pinching action alternately on the upper and lower regions of the shoe which remain in contact with the relatively movable opposing member of the truck. This operating condition effects momentary excessive gripping and abrupt releasing of the wedge and consequent chattering of the friction shoes during their vertical movements and thereby reduces their frictional efficiency. The pinching and tilting of the friction shoes also efiects undue localized wear on the shoes in the regions of their upper and lower edges in a manner to permanently reduce the area of their frictional faces.

A principal object of the present invention is to obviate the above objectionable operations. This general object is attained by the provision of a stabilizing mechanism in which the friction shoe elements are so constructed and arranged as to effect self-alignment of their respective friction faces with wear surfaces on an opposing relatively movable member of the truck. In this connection the invention contemplates as a specific object the provision of a friction element comprising a main body portion and a removable friction face portion which is pivotally attached thereto and is adapted to maintain its friction face in flat surface alignment with an opposing friction face on a relatively movable member of the truck during the above rocking movements of a side frame relative to the bolster.

According to the present invention, a truck bolster structure supported on load springs of a truck and connected, in a known conventional manner to the car body, oscillates in a prescribed vertical plane and its opposite side walls are provided with wedge-shaped pockets which serve to house wedge-shaped friction shoes adapted to bear against opposed vertical columns of the truck side frames. An actuating spring for each friction wedge serves to press the inclined face of the wedge against a 3,024,743 Patented Mar. 13, 1962 correspondingly inclined Wall of the pocket in which it is housed, whereby the reaction force thus developed presses the outer frictional face of the wedge into frictional contact with an opposing vertical column of a side frame of the truck so as to damp the vertical oscillations of the truck bolster and consequently damp the vertical oscillations of the load springs.

In order to avoid the undesirable effects incident to variations of. the angle between a unitary friction wedge and a vertical column of a side frame or other truck member opposing such wedge, which variations as previously indicated reduces the frictional efficiency of the friction wedge, the friction face of each wedge member of the present invention is formed separate from the main body of the wedge and is pivotally associated with the said main body so that the said friction face will freely adjust its position in response to the rocking movements of an associated side frame and be thereby automatically maintained in alignment with an opposed friction face of a vertical column of the side frame or such other element of the truck as may be frictionally engaged by the friction wedge.

A preferred embodiment of the invention is shown in the accompanying drawings wherein:

FIG. 1 is a fragmentary side view of a railway car truck provided with stabilizing mechanism constructed in accordance with this invention, parts of the bolster and side frame being shown in section to better illustrate the improved constructions;

FIG. 2 is a sectional view taken substantially on line 22 of FIG. 1;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1 looking in the direction of the arrows;

FIGS. 4 and 5 are side and bottom plan views, respectively, of a friction wedge assembly constituting a part of the truck stabilizing mechanism; and

FIG. 6 is a view in perspective of the said friction wedge assembly showing the friction face portion thereof separated from the body of the wedge.

Referring to the drawings: Inasmuch as the opposite sides of the railway car truck herein shown includes identical parts, the drawings and the description of the truck for the sake of brevity, are confined to the constructions and arrangements at one side of the truck; it being understood that a complete truck includes identical parts and arrangements at both sides thereof.

The truck structure shown herein includes, in its general organization, a bolster 10 supported on load springs 11 seated on a tension member 12 of a truck side frame 13. The opposite side walls of the bolster are provided with pockets 14, 15, the rear walls 16, 17 of which incline upwardly and outwardly toward the side walls of the bolster so as to impart to each of said pockets a wedge-shaped configuration. Friction wedge assemblies of like construction and designated generally by numerals 18 are housed in said pockets 14, 15 in positions to bear against opposing columns 19, 20 of the side frame 13. Wedge actuating springs 21, associated with the wedge assemblies, maintain the said wedge assemblies in their operative positions between the bolster 10 and the columns 19, 20 of the side frame. The said springs 18 are so positioned that the center line A of each spring in tersects the inclined face of the rear wall of its associated wedge pocket at substantially the midpoint between the upper and lower ends of said inclined face. The load springs 11 are maintained in proper position by centering lugs 22 formed on the bottom face of the bolster and by upstanding lugs 23 formed on the said tension members 12 of the side frame. Similar centering lugs 24, 25 are formed on each wedge assembly and on said tension member 12, respectively, to maintain the wedge actuating springs 21 in their operative positions.

The truck columns 19, 20 are positioned in spaced relation to each other and connect the lower tension member 12 with a top compression member 26 in a manner to define a window opening 27 for receiving a box end portion 28 of the bolster 10. The compression member 26 and the tension member 12 converge toward their extremities and are united with each other to pro vide a pedestal construction adapted to be supported on a conventional housing 28 enclosing a journal and bearing of an axle (not shown) but associated with the wheel 29.

The box portion 28 of the bolster projects through the window opening 27 and is provided with inboard and outboard guide lugs 30, 31 which embrace the inboard and outboard side faces, respectively, of the vertically extending columns 19, 20 of the frame so as to interlock the bolster with the side frame. Wear plates 32, 33 of hardened steel are interposed between the wedge assemblies 18 and the vertical columns 19 and 20- of the side frame, the wear plates being suitably secured by welding or by other conventional means to the inner faces of said vertical columns.

In order to facilitate the assembly of the bolster end 28 in a side frame 13 of a truck, the lower portion 34 of the bolster window 27 is made of sufficient width to permit the outboard lugs 31, 31 on the bolster to pass therethrough. Preferably, the upper ends of the lugs 31, 31 stop short of the top face of the bolster so that the enlarged portion 34 of the bolster window 27 may be made of minimum height. After the outboard lugs 31, 31 clear the outer faces of the columns 19, 20, the bolster may be elevated to a position within the window 27 to permit the load springs 11 and the wedge assembly actuating springs 21 to be inserted in their operative positions beneath the bolster and the wedge assemblies, respectively. The springs 11 and 21, as illustrated in the drawings, are so-called long travel springs" and are shown partially compressed under the weight of the bolster and car body. The said springs when free of the weight of the bolster and the car body are expanded to such extent that it is necessary to elevate the bolster to the extreme upper end of the bolster window 27 before the springs 11 and 21 can be inserted in their operative positions. Therefore, in order to provide the wedge assemblies with friction faces of maximum height so as to provide maximum area, and, at the same time, provide adequate backing for the said assemblies, the inclined walls 16, 17 of the pockets 14, 15 are extended above the top face of the bolster as indicated in FIG. 1 at 36. The bottom face of the compression member 26 is provided with an elongated opening 37 adapted to receive the said extensions 36 as well as the upper ends of the wedge assemblies when the bolster is elevated to its maximum height in the bolster window to facilitate installation of the springs 11 and 21.

The wedge assemblies, in each case, comprise a main body portion 38 and a separately formed friction plate 39. The forward face of the body is provided with a semi-circular transverse recess which serves as a socket 40 for receiving a semi-circular bearing portion 41 formed on the friction plate 39. When the two elements 38 and 39 are in their assembled relation said semi-circular socket 40 and bearing 41 are located between the ad jacent end of a wedge spring and the inclined portion of the rear wall of an associated wedge pocket and consequently lies within the direct line of thrust of the wedge spring and the plate 39 may be freely tilted to various angular positions relative to the main body 38 of the wedge, for the purpose hereinafter explained. The main body 38 of each wedge assembly is provided with a rear inclined face 42 which, when the wedge assembly is fitted into one of the pockets 14 or 15, will bear against the inclined rear wall of such pocket. The actuating spring 21, it will be observed, functions to urge the inclined face 42 of the wedge assembly against the correspondingly inclined rear wall of the pocket in which the wedge is housed. The reaction force thus developed presses the outer friction face 43 of the adjustable friction plate 39 firmly against the opposing face of a wear plate 32 or 33 mounted on columns 19 or 20 of the side frame.

The component parts of the wedge assembly are held in their assembled relation by means of the reaction force developed by the spring 21 and the wedging action of the wedge against the rear wall of its associated pocket. However, the plate 39 retains its capacity for free rocking movement, whereby the friction plate 39 will automatically so change its position, in response to the rocking movement of the frame as to maintain the entire area of the friction face 43 of the wedge assembly in fiat sliding contact with an adjacent wear plate 32, 33, regardless of variations of the angle between the Wear plates and the bolster as an incident to the rocking or galloping movements of the truck side frame relative to the bolster. By virtue of this automatic tilting of the friction plate 39 of the wedge assembly in harmony with the angular movements of the columns 19, 20 and consequently in barmony with the angularity of the Wear plates 32, 33 a flat interface contact is maintained at all times between the friction face 43 of the tiltable friction plate 39 of the wedge assembly and an adjacent wear plate 32, 33 engaged thereby.

In actual practice, the friction plates 39 are made of softer steel than the wear plate 32, 33 and consequently are subjected to more wear than the wear plate 32, 33. However, the wear on the friction plate 39 is uniform throughout the entire area of its friction face 43, since the pressure is applied thereto at its medial region. When the friction plate 39 becomes worn sufficiently to require replacement, it can be readily removed from the main body 38 of the wedge assembly and a new plate 39 may be applied. This renewable feature is made practical in connection with the present invention, since the wear on the wear plates 32, 33 is such as to maintain their friction surfaces perfectly flat and therefore insure flat contact of the renewal friction plate.

The upper edges of the main body 38 of the wedge assembly and the upper edge of the friction plate 39 are reduced in width as indicated at 44 and 45, respectively, so that these portions of reduced width may readily pass through the opening 37 formed in the bottom face of the compression member 26 of the side frame. The lower edge 46 of the wear plate 39 is reduced in width so as to provide suitable clearance recesses 47 for the adjacent convolutions of the load springs l1, 11 as shown best in FIGS. 2 and 6.

We claim:

1. A stabilized car truck including a side frame having a bolster window therein, a bolster having a box end portion projecting into said window and formed with a wedge receiving pocket opening through one side face of the bolster and formed with a rear wall provided with an upwardly and outwardly inclined face, load springs interposed between the bolster and a subjacent portion of the side frame to resiliently support the bolster with capacity for vertical movements relative to the side frame, means for damping said vertical movements of the bolster comprising a wedge element positioned in said pocket for cooperating wedging engagement with said inclined face thereof, a separate friction plate element having a fiat frictional interface with a portion of the side frame and having also a pivotal attachment with said wedge, whereby the friction plate element may tilt relative to the wedge without disturbing said flat interface contact of the friction plate with the frame, and a wedge actuating spring interposed between said wedge and a portion of the side frame to force the wedge into wedging engagement with said inclined face of the wedge pocket and thereby force the friction plate element against said engaged portion of the side frame; the said wedge spring being so positioned that its longitudinal center line of thrust intersects a medial portion of said inclined face of the wedge pocket, and the said pivotal attachment of the wedge and said friction plate element being petitioned in the line of thrust of the wedge spring at a location between the wedge spring and the inclined face portion of the rear wall of said pocket.

2. A stabilized car truck according to claim 1 wherein said pivotal attachment of the wedge element and the friction plate element include a semi-cylindrical socket formed in the outer face of the wedge element at a location overlying the adjacent end of the wedge spring and a semi-cylindrical medial bearing on the friction plate element fitted into said socket.

3. A stabilized car truck according to claim 2 wherein the inclined face of the rear wall of the pocket projects above and below the top wall of the bolster and the point at which said face is intersected by the center line of thrust of the wedge spring lies substantially midway between the upper and lower ends of said inclined face.

4. A stabilized car truck according to claim 3 wherein the friction plate element is of sufiicient length to project above and below the planes of the top and bottom surfaces, respectively, of said box end portion of the bolster to provide the plate with maximum frictional area, and the lower corners of said plate are recessed to provide clearance for the upper convolutions of the adjacent load springs.

References Cited in the file of this patent UNITED STATES PATENTS 2,574,348 Orr et al. Nov. 6, 1951

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