NZ198643A - Wear indication for railway bogey friction snubber:notch cut in friction surface - Google Patents

Description

198643 Priority Date{&}: Complete Specification Filed: Class: .Ml?.5/n... .f1-g-m-m- Publication Oate: P.O. Journal No: 7.3......

NEW ZEALAND PATENTS ACT, 1953 No.: - ; ^ Date: ■/' 0 r,. • ■"'A COMPLETE SPECIFICATION ' « ^ » \ K ' FRICTION SHOE WEAR INDICATOR - ¥/We, AMSTED INDUSTRIES INCORPORATED, 3700 Prudential Plaza, Chicago, IL 60601, a corporation organized and existing under the laws of the State of Delaware, United States of America hereby declare the invention for which ¥ / we pray that a patent may be granted to nox^us, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 -• (followed by page la) 198043 | Background and Summary of the Invention ! I I 1 | The present invention relates to frictionally snubbed railway car trucks, and more particularly to a modification to a friction shoe located between the bolster and the side frame to indicate the combined wear of various control surfaces.

The use of friction shoes as snubbing devices to control the oscillating movements of the bolster in the side frame is known. Arrangements for using such friction shoes are shown in U.S. Patent Nos. 2,953,995 and 4,109,585, both assigned to the assignee of the present invention.

The type of railway car truck to which the present invention is generally related comprises spaced side frame members each having an opening arranged to resiliently support opposite ends of a bolster. The bolster and side frame form two wedge-shaped openings at either end of the bolster. A spring biased friction shoe is provided in each wedge-shaped opening. The friction shoe frictionally engages both the side frame and the bolster for controlling the oscillating movement of the bolster.

Satisfactory results are obtained in limiting the oscillating motion of the bolster only as long as the friction parts are not allowed to develop excessive wear. Such a condition will cause the biasing springs to exert a force which is out of tolerance and thus becomes ineffective in dampening bolster oscillations. \ 198643 An indicating arrangement for determining when the friction shoes themselves have developed excessive wear is shown in U.S. Patent No. 3,805,707, assigned to the assignee of the present invention. In that arrangement, a wear indicator hole is provided in the bolster. The wear indicator hole enables a viewer to compare the present position of the friction shoe to a previously established reference. Thus the present position of the friction shoe enables the viewer to determine the wear remaining in the friction shoe, but is in a rather difficult to view location and becomes hidden if a certain limit of wear is exceeded.

It is therefore an object of the present invention to.provide an easy to view indication of the combined wear of the various friction contact surfaces in the railway truck.

It is a further object of the present invention to provide an indicating means on the friction shoe itself which, when referenced with the bolster top, readily indicates the combined wear of the bolster and the side frame contact surfaces, as well as the friction shoe itself, for wear conditions ranging from new to and beyond the replacement wear limit.

Brief Description of the Drawings In the drawings: Figure 1 is a fragmentary side elevational view of a railway car truck embodying the present invention; Figure 2 is a detailed fragmentary side elevational view of a railway car truck bolster and friction shoes; 198643 Figure 3 is a fragmentary side elevational view of a railway car truck bolster, side frame and friction shoes embodying the present invention; Figure 4 is a detailed side elevational view of the side frame column, bolster and friction shoe, with the shoe indicator in an unv?orn position; Figure 5 is a detailed side elevational view of the side frame column, bolster and friction shoe, with the shoe indicator in a worn position.

Description of the Preferred Embodiment Referring now to Fig. 1 of the drawings, there is shown a side frame 10 having a pair of columns 12 defining the sides of a bolster opening 14 formed in the frame.

One end of a bolster 16 is resiliently supported in the bolster opening 14 on outer load springs 11 and inner load springs 13. Friction plates 20 may be integral with or suitably mounted on side frame columns 12.

As best seen in Figs. 2 and 3, friction shoe 24 comprises a body portion 26 having a friction wall 28 which frictionally engages a friction surface 30 on side frame column friction plate 20. Friction shoe 24 is urged into frictional engagement with plate 20 by control spring 23. Control spring 23 is received in a central spring pocket formed in friction shoe 24 and is compressed between a lower wall 36 of bolster 16 and an upper wall 39 of friction shoe 24. The spring urges an upper surface 40 of sloped wings 42, which project outwardly from opposite sides oi" body portion 26 of friction shoe 24, into engagement with a guiding surface 44 of bolster 16. 1 Q ^ 5 *• As best seen in Figures 4 and 5, friction wall 28 of friction shoe 26 is modified such that an indicating recess or indentation or notch 48 is present. jSuch recess would most commonly be formed in the friction shoe during the casting operation. A normal or unworn friction shoe and adjacent friction surfaces are shown in Fig. 4..

Note that the indicating recess 48 is below top wall 38 of the bolster 16. However, as friction shoe 24 and adjacent friction surfaces are worn by the oscillating motion of bolster 16 in side frame 10 during operation, the friction surfaces will become worn. Accordingly, as shown in Figure 5, friction shoe 24 will rise due to the worn surfaces and indicating recess 48 will become visible above top wall 38 of bolster 16. The length of indicating recess 48 will be such that when the recess is entirely visible above bolster 16, corrective maintenance or replacement of friction shoe 24 or other friction surfaces should be undertaken.

Thus the present invention is seen to provide an indicating means to readily show an inspector when corrective maintenance of the friction dampening mechanism of the railway car truck should be undertaken. Other embodiments of the present invention not incorporating all the specific features of the above-described embodiments are considered part of the present invention, which is to be limited only as set forth in the following claims~>-

Claims (4)

19~8G43 "WHAT l/WE CLAIM IS:

1. A friction apparatus for a railway car truck comprising a side frame having a substantially upright column partially defining a bolster opening, a bolster resiliently supported in a said opening for vertical movement therein, said bolster having top and bottom walls, a vertical planar surface on said column, a top wall and a guiding surface on said bolster, a friction shoe comprising a body, a substantially vertical wall, a sloped surface and a spring pocket, a control spring located in said spring pocket of said friction shoe for urging said friction shoe vertical wall into frictional contact with said column vertical planar surface and said sloped surface into frictional contact with said guiding surface on said bolster, wherein the substantially vertical wall of said friction shoe has a recessed indicating notch which is below the top wall of said bolster when said friction shoe is under unworn conditions and which extends above said top wall of said bolster so as to be always visible when the vertical and sloped frictional contact surfaces of said friction shoe are worn.to near their service limit.

2. In a railway car truck including a bolster resiliently supported on spring groups in side frames between spaced vertical columns thereof, said bolster having slope surfaces on both sides thereof, two friction shoes each having I / 198043 I a slope face and a vertical face interposed between each bolster slope surface and vertical column, respectively, a control spring for urging the friction shoe into frictional engagement with the bolster slope surfaces and the vertical columns, wherein the vertical face of the friction shoe includes a recessed indicating notch which is below the upper surface of the bolster when the friction shoe is under unworn ^conditions and which extends above the upper surface of the bolster so as to be always visible when the friction surfaces of the friction shoe adjacent the bolster slope surface and vertical columns become worn to near their service limit.

3. A friction apparatus, for a railway car truck, substantially as herein described with reference to the accompanying drawings.

4. A railway car truck incorporating the friction apparatus as claimed in claim 1 or claim 3. , DATED THIS \ DAY OF tSf^r A. J. PARK & SON PER AGENTS FOR TFIE APPLICANTS * ? $