US2975869A

US2975869A - Railway car brake mechanisms

Info

Publication number: US2975869A
Application number: US601768A
Authority: US
Inventors: Charles R Busch
Original assignee: Buffalo Brake Beam Co
Current assignee: Buffalo Brake Beam Co
Priority date: 1956-08-02
Filing date: 1956-08-02
Publication date: 1961-03-21
Anticipated expiration: 1978-03-21

Description

March 21, 1961 C R BUSCH RAILWAY CAR BRAKE MECHANISMS Filed Aug. 2, 1956 4 Sheets-Sheet 1 All 5 P w 56 W fxxzzi zm I (M l 1 March 21, 1961 c, BUSCH 2,975,869

RAILWAY CAR BRAKE MECHANISMS Filed Aug. 2, 1956 4 Sheets-Sheet 2 INVENTOR 5941?!!! A? 50.52%

BY I

ATTORNEY March 21, c R BUscH RAILWAY CAR BRAKE MECHANISMS Filed Aug. 2, 1956 4 Sheets-Sheet 3 limu' a (24424:: i? 5 00/ I K) 0 ATTORW RAILWAY CAR BRAKE MEHANISMS Charles R. Busch, Grange, N..l., assignor to Buffalo Brake Beam Company, a corporation of New York Filed Aug. 2, 1956, S21. No. 601,768

6 Ciaiins. (Cl. 138-59) The present invention relates to railway car brake mechanisms, especially of the freight type and of the general type described in, my copending applications Serial No. 491,838, filed March 3, 1955; Serial No. 532,635, filed September 6, 1955, and Serial No. 554,476, filed December 21, 1955, now matured into Patents No. 2,903,096, No. 2,903,097, and No. 2,903,098, respectively, all issued September 8, 1959.

In the railway car brake mechanism disclosed in the aforesaid applications, four linkages in each car truck powered from an air power system, operate brakes against brake discs rotatable with respective car wheels. The car body is mounted on a truck bolster spring-supported at its ends on the side frames of the truck, and each of the linkages comprises an L-shaped brake head lever, having one leg extending along the bolster and pivotally connected to a bracket afixed to the side frame, and having the other leg extending transversely of the bolster and carrying the brake head for the brake shoe.

In the constructions of the aforesaid applications, the brake shoe is connected to the brake head through a rocker serving as a face plate for said brake head, so that the brake shoe swivels with the rocker and compensates for the arcuate swing of the lever about its pivot support, thereby assuring uniform braking pressure against the full area of the brake shoe. The swivel connection between the rocker and the brake head comprises a series of sockets in the brake head, lugs in the rocker extending into said sockets respectively, said lugs and brake head having aligned holes, and a pivot key or pin passing through said holes, the confronting faces of the brake head and the rocker affording a clearance therebetween permitting swivelling of the rocker about the axis of the key. One object of the present invention is to provide a new and improved swivel connection between the rocker and the brake head, which is biased to maintain the braking face of the shoe carrying rocker in alignment with and parallel to the braking face of the brake disc in brake released position of the brake head lever, which is yieldable to permit the shoe to adjust itself to the braking face of the brake disc in braking position as the brake head lever moves about its pivot support, to assure uniform braking pressure against the full effective area of the brake disc in spite of wear in the brake shoe, and which is operable to maintain the bearing connection between the rocker and the brake head sufficiently tight to prevent vibration between the parts of said connection and to reduce therebywear of the rocker and of said parts.

In accordance with certain features of the present invention, the back of the rocker has lugs with holes aligned with a hole in the brake head of the brake head lever to receive a pivot key or pin. Between the rocker and the brake head lever is a pad of elastomeric material such as rubber, acting as a means for holding the shoe supporting face of the rocker in alignment with and parallel to the braking face of the brake disc in brake released position of the brake head lever and having the resiliency atent ice to permit the shoe to adjust itself to the braking face of the brake disc to assure uniform braking pressure on the braking face of the brake disc. At the same time, the rubber pad, being under compression, holds the connections between the pivot key or pin and its bearings tight, thereby preventing vibration and wear at these connections.

Various other objects, features and advantages of the invention are apparent from the following description and from the accompanying drawings, in which:

Fig. 1 is a general top plan view somewhat diagrammatic of a railway car brake mechanism having incorporated therein features of the present invention;

Fig. 2 is a detail section of the railway car brake mechanism taken on lines 2-2 of Figs. 1 and 3, but shown on a larger scale than in Fig. 1;

Fig. 3 is an enlargement of a part of Fig. 1 showing the brake mechanism in connection with a single car wheel;

Fig. 4 is a top plan view of the brake head lever embodying the present invention;

Figs; 5, 6 and 7 are diflferent views of the brake head lever taken on lines 5-5, 6-6 and 77 of Fig. 4, respectively";

Fig. 8 is a section of the brake head lever taken on lines 3-8 of Fig. 4;

Fig. 9 is a detail section of the brake head lever, the shoe supporting rocker and the resilient swivel connection therebetween, taken along the lines 99 of Fig. 3 and Fig. 10 but shown on a scale larger than in Fig. 3;

Fig. 10 is a detail section of the brake head lever, the shoe supporting rocker and the resilient swivel connection therebetween, taken along the lines Ill-10 of Fig. 9 and shown in the brake released position of the lever;

Fig. 11 is a rear face view of the shoe supporting rocker;

Fig. 12 is a section of the shoe supporting rocker taken on lines 1212 of Fig. 11; and

Fig. 13 is a perspective of the resilient pad employed in the connection between the brake head lever and the shoe supporting rocker and shown in unstressed condition before its inclusion into the brake assembly.

The railway car brake mechanism illustrated in Figs. 1, 2 and 3 is in certain respects similar to that shown in the aforesaid copending application Serial No. 532,635, now patent No. 2,903,097, and similarly comprises a pair of side frames 10 having respective guide openings 11 to receive the ends of a truck bolster 12 extending between said frames and projecting at the ends into said openings, where they are supported on coil springs (not shown) and are guided by side columns 13 of said openings for vertical shock-absorbed movement. The bolster 12 is provided with a center conformation 16 for direct pivotal connection to the underside of the railway car body (not shown) in conventional manner.

Between the two side frames 10 and supported thereon bysuitable bearings are two parallel axles 17 carrying at opposite ends flanged car wheels 18 which ride on rails (not shown).

The brakes for the four car wheels 18 of each car truck are operated by four similar brake head levers 20, symmetrically and quadrilaterally arranged and actuated from a single source of power. These brake head levers 29 are supported from respective brackets 21 flanking the bolster 12 and rigidly connected to the side frames 10 on opposite sides of the bolster guide openings 11.

Each brake head lever 20 is L-shaped and has one leg 25 pivotally connected to the end of the bracket 21 by a hinge or pivot pin 26 to permit said lever to move horizontally about the axis of said pivot pin into and out of braking position and has its other leg 27 carrying at its end a V 3 r v V brake head'28. This brake head 28 mounts a rocker 29, which serves as a face plate for said brake head, and which supports a brake shoe 30 inposition, to be applied to a brake rotor or disc 31 aflixed tothe corresponding car wheel 18, so that said disc and in turn the car wheel may be stopped. The rocker 29 is mounted on the brake head 28 with an improved resilient swivel connection permitting limited pivotal movement of the rocker on the brake head and allowing thereby the brake shoe to adjust itself automatically into conforming surface contact with the brake disc 31 upon application of the brake. The details of this feature of the invention will be described fully hereinafter.

The brake head levers 20 are supported and steadied in their horizontal movements into and out of horizontal position, to prevent the application of destructive stresses to different parts of the mechanism and especially to the hinge pin 26, and the braking forces tending to distort the side frames inwardly out of parallelism and out of alignment with the wheel journals are resisted, while permitting said sideframes to shift relatively endwise as the wheels 18 round a curve. To that end, there are provided two horizontal equalizer bars 35 on opposite sides of the bolster 12, each bar being pivotally connected to the two side frame brackets 21 on the corresponding side of the bolster. For securing each equalizer bar 35 to the corresponding pair of side frame brackets 21, the two hinge pins 26, which pivotally connect the corresponding two brake head levers 20 to said brackets, also pass through the ends of the equalizer bar. To provide between each side frame bracket 21 and the corresponding brake head lever 20 a hinge connection permitting the corresponding end of the equalizer bar 35 to be pivotally secured to said connection, the bracket has a pair of axially spaced superposed projections 36 and 37 (Figs. 2 and 3) disposed at opposite ends of a hub 38 at the end of the lever 20 to form a knuckle joint therewith. The

projections

36 and 37 and the hub 38 are retained in interconnected pivotal relationship by the hinge pin 26 passing through axially aligned openings in said projections and said hub. The equalizer bar 35 is in the form of an angle bar, one horizontal leg 40 of which is seated at each end upon the lower projection 37 of the corresponding side frame bracket 21, while the other leg 41 extends downward from said projection, and the leg 40 has a hole at each end through which the corresponding hinge pin 26 passes.

. To afford a large bearing area between the equalizer bar 35 at each end and the corresponding hinge pin 26, there is welded or otherwise affixed to the leg 40 of the equalizer bar at each end over the hole in said leg, a collar 42 located between said leg and the hub 38 on the corresponding brake head lever 20 and embracing the hinge pin with a snug rotative fit. This collar 42 also serves to afford clearance for the support shoe on the corresponding brake head lever 20, as will be more fully described.

Power is applied to the brake head levers 20 through a pair of similar bridle beams 43 (Figs. 1, 2 and 3) disposed on opposite sides of the truck bolster 12. These beams 43 extend horizontally across the center line of the car truck with the middle points of said beams on said center line. For supporting the bridle beams 43 and guiding them for horizontal movement along the center line of the truck, each of the equalizer bars 35 has secured thereto two supports 44 spaced to seat thereon the corresponding bridle beam 43 at spaced regions thereof on opposite sides of its middle point.

For applying power to the bridle beams 43, each of said bridle beams is integrally formed at its center region with a pair of pivot jaws or projections 50 extending obliquely upward and defining therebetween a socket to receive the lower end of an inclined lever. One of the bridle beams 43 receives the lower end of an inclined somewhat upright live lever 51 in the'socket between its pivot jaws 50 and is pivotally connected thereto by a pin. The upper end of this live lever 51 is pivotally connected to a pull or power rod 53 operated from a lever (not shown) of the air cylinder (not shown), which is supported in the usual manner on the car body and which forms part of the conventional air brake equipment.

Power is transmitted from the bridle beam 43, to which the live lever 51 is connected, to the other bridle beam 43 by means of a connecting rod 54- passing through aligned openings 55 in the side walls of the bolster 12. This connecting rod 54- is pivotally connected at one end to the intermediate section of the live lever '51 and pivotally connected at the other end to the intermediate section of an inclined somewhat upright dead lever 57. The lower end of this dead lever 57 extends into the socket between the jaws 5-0 of the corresponding bridle beam 43 and is pivotally connected thereto by a pin, and the upper end of this lever is connected to the truck bolster 12 by a flexible coupling 58.

With the brake operating mechanism so far described, when the pull rod 53 is moved to the left (Fig. l), as the result of the application of braking power, the bridle beam 43 to the right of the bolster 12 is moved to the right along its supporting guides 44 by the angular movement of the live lever 51 about its pivotal connection to the connecting rod 54. At the same time, this connecting rod 54 is moved by this action endwise towards the left, thereby causing the bridle beam 43 to the left of the bolster 12 to be moved towards the left along its supporting guides 44 by the action of the dead lever 57 pivotally connected to said connecting rod and to the latter bridle beam.

The almost simultaneous operation of thetwo bridle beams 43 upon the application of the brake power through the pull rod 53 as described, is transmitted substantially simultaneously to the four brake head levers 20, to cause said levers to move about their pivotal supports 26 into braking position in relation to the brake discs 31. To effect the necessary connections between the bridle beams 43 and the brake head levers 20 for this purpose, each of the brake head levers has besides the two angularly

related legs

25 and 27, a third leg '70 in substantially longitudinal alignment with the leg 25, so that the lever is in the form of a T. The outer end of each lever leg 70 is connected to the adjacent outer end of the corresponding bridle beam 43 by means of a link 71. By means of this construction, each bridle beam 43 on each side of the bolster 12 is linked at its ends to a pair of brake head levers 20 on the same side of the bolster, to actuate said levers simultaneously into brake applying position, as the bridle beam moves laterally sideways away from the bolster 12 along the center line of the truck.

The brake head lever 20 shown in Figs. 28 is substantially of T cross-section and comprises a comparatively wide marginal reinforcing flange 75 extending continuously along one side of thelever leg 25 and along the corresponding side of the lever leg 27, a web 76 in the form of a flat plate constituting the body of the lever, a comparatively narrow marginal reinforcing flange 77 extending continuously along the opposite side of the lever leg 25 and along the corresponding side of the lever leg 70, and a similar narrow marginal flange 78 extending along the other side of said lever leg 74) and along the other side of said lever leg 27. This lever construction alfords the greatest strength along the wide flange 75 where the greatest stress takes place and at the same time presents the necessary large area at the outer end of the lever leg 27, where the brake head 28 is formed.

One end of the lever leg 25 terminates in the hub 38 extending transversely of the web 76 of the lever 20 from opposite faces thereof for equal distances to form a bearing for the hinge or pivot pin26 longitudinally centered with respect to said web. This hub 38 terminates at its ends in respective rims or ridges 81 into which'the

marginal flanges

75 and 77 of the lever 20 merge. The axially spaced

superposed projections

36 and 37 flanking opposite ends of the lever hub 38 to form a knuckle joint therewith, are secured to said hub by the pivot pin 26 passing therethrough with a rotative bearing fit.

The web 76 at the outer end of the lever leg 70 is of enlarged thickness coextensive with the width of the

flanges

77 and 78 to form a flat solid end section 84 for engagement between the arms of a clevis at one end of the link 71 and has an aperture to receive a pivot pin.85 (Figs. 2 and 3) connecting said link to the lever leg 70.

The equalizer bar 35, besides serving to hold the side frames in alignment during brake application, while permitting said side frames to shift endwise in parallelism when rounding a curve and to support the bridle beams 43 in their operating movements, also serves to support the weights of the brake levers 20, thus relieving the hinge pins 26 from excessive stresses. To the latter end, each of the brake head levers 20 has a support shoe 86 at the bottom of the section of the brake head lever at the region thereof proximately between the outer end of the lever leg 25 and the inner end of the lever leg 70. This support shoe S6 is integrally connected to the web 76 of the lever 2t) by means of a column 87 depending from said web and is seated on the equalizer bar 35 as shown in Fig. 2. The cloumn 87 is of cruciform cross-section and the shoe 86 is in the form of a fiat plate of somewhat elliptic shape parallel to the web 76. The shoe 86 maintains the lever it? in horizontal position, thereby steadying said lever against vibration during normal running operations when the brakes are disengaged and also guiding the lever horizontally in its brake applying and releasing movements.

If each brake head lever 20 is provided with a single support shoe 86 at the bottom, then although the brake head lever aside from the shoe may be placed interchangeably on one or the other of two diagonally opposite corners of the quadrilateral system of levers 20, when the brake head lever is placed at any other corner of this system, it must be turned upside down, so that a shoe which was on the bottom side of the brake head lever and operative when the lever is in one position in the system, will be on the top side and inoperative when in another position in the system. Under these conditions, it would be necessary to provide a left hand brake lever and a right hand brake head lever. To avoid this, and to make all of the four brake head levers 2i) on each truck interchangeable in any one of the four positions, each of the brake head levers has two similar support shoes 86 and 83, one on the bottom and one on the top in vertical alignment, the upper one 88 being integrally connected to the web 76 through a column 91 similar to the column 87 carrying the bottom support shoe 86. With the construction described, the brake head lever 20 on either side or the bolster or at either end of the bolster, will have a bottom support shoe in seating and supporting engagement with the corresponding equalizer bar 35, even though all of the brake head levers 20 are of the same construction and design.

Positive spring releases were provided in the construction of the aforesaid copending application Serial No. 554,476, now patent No. 2,903,098, to move the brake head levers 2% out of braking positions upon the release of the braking power. Spring releases are provided in the construction described herein similar to those of the construction of the aforesaid application, except for the parts connected with the actual design of the brake head levers 2%. Each of these releases comprises, as in the construction of the aforesaid copending application, a plunger 5 (Figs. 2 and 3) in the form of a bolt having a rounded head at one end and threaded at the other end to receive a nut. Encircling the plunger 95 is a coil spring 96, one end of which bears against a Washer or collar on the plunger thrust against the head of said plunger, the other end of which fits into a cup 97 provided with an end abutment wall through which the plunger slidably extends and against which it bears. The

6 spring 96 in its expanding movement, tends to move the plunger towards the right, as shown in Fig. 3, this movement being limited by the stop engagement of the nut with the end wall of the spring cup 97.

The spring cup h 7 is supported on the corresponding equalizer bar 35, and for that purpose has a bracket extension consisting essentially of a plate bearing against the equalizer bar and rigidly secured thereto.

For transmitting the force of each spring 96 to the corresponding brake head lever 20, each of said brake head levers has a lag 1100 (Figs. 5, 6 and 8), which depends from the [bottom of its leg 25 near the outer end thereof on the side nearest the bolster 12, and which is integral with the lever. This lug 1.0% is in the form of a flat oblong plate and its front face engages the head of the plunger 95 to serve as a tappet for the brake head lever 20. Integral with the rear face of the lug ltwand extending therealong is a reinforcing rib 101. The lug 1G0 and its rib ltil form a structural unit of T crosssection and extend to the web 76 and to the flange 77 into which this unit integrally merges.

With the construction described, upon application of the braking power through the pull or power rod 53, each of the brake head levers '20 is moved angularly about its pivot support 26 in position to apply its brake shoe 3%) to its corresponding brake disc 31, while coinpressing the spring 96 of the corresponding spring device. Upon release of the braking power, the springs 96 are'also released, causing them to return into expanded condition. These expanding movements of the released springs 96 are transmitted to the brake head leversZtl through the plungers 95 and lugs 10!), causing said brake head levers to be moved positively about their pivot supports '26 out of braking positions and away from the corresponding brake discs 31.

Since the brake head levers 20 are intended to'be interchangeable, so that they can operate on either side of the truck bolster 12 or at either end of the bolster truck, each of the brake head levers 20 is not only provided with a lower lug dfit) but is also integrally provided with a similar upper lug 162 with a reinforcing rib 103 located directly over the lower lug Hit) and lower rib 10d and extending upward from the web 76. The upper lug 102 is not active but comes into operation when the brake head lever 26 is disposed in position Where this lug extends from the bottom. In this position, the upper lug 102 cooperates with a spring release device as described to function in the manner already indicated.

An important feature of the present invention resides in the swivel and resilient connection between the rocker 29 and the brake head 23. This resilient connection comprises a generally fiat pad 1&5 (Figs. 9 to 13) of rectangular oblong outline, made of elastomeric material,

such as rubber, and located between the confronting faces of the brake head 28 and the rocker 29. These confronting faces are substantially flat and are substantially parallel in released position of the brake head lever 20, and these faces entirely cover the opposite faces of the pad 1&5, so that the pad sandwiched between the brake head 23 and the rocker 2.9 is unobstrusive and effectively protected against injury. This pad 105 is of double taper design and comprises two simliar opposed wedge-shaped sections 1% tapering towards the center where they merge. As a result of this double wedge construction of the pad 1%, the rear side of the pad secured to the brake head '28 presents two fiat faces 107 converging at a wide angle towards the center of the pad. The front side of the pad ltiS'to which the rocker 29 is secured presents two flat faces lti; also converging towards the center of the pad but preferably at an angle greater than that between the rear faces Th7, so that these faces 168 are almost in the same plane.

The brake head 28 is integrally and solidly formed in the brake head lever 20 partly by the end of the marginal flange 75 of the brake head lever and partly by a thereto.

hearing or trunnion block 110 (Figs. 3-7, 9 and 10) between the rocker 29 and said brake head. This bearing block 110 is provided with a hole 111 to receive a vertical pivot pin 112 and is reinforced by a rib 113 extending between said block and the marginal flange 78 of the brake head lever 20. The bearing block 110joins integrally into the marginal flange '75 of the brake head lever 20, and said block as well as its ri'o 1'13 extend equal distances from opposite faces of the web 76 of said brake head lever, so as to be centered with respect The section 114 of the front face of the brake head 28' at its extreme end beyond the axis of the hearing block 110 is bevelled for the purpose to be made apparent.

The front side of the brake head 28 has a recess 1115 (Figs. 4, S and 10) conforming in outline to the oblong rectangular outline shape of the rubber pad 105 and having a base of double slope in conformity with the rear sloping faces 107 (Figs. 10 and 13) of said pad to receive snugly and conformably therein the rear section of the pad 105 including said sloping faces 107. The front section of the rubber pad 105 projects beyond the front face of the brake head'28.

The outer end section of the recess 115 is shallower than the inner end section due to the bevelling of the front section 114 of the brake head, to cause the outer end of the pad 105 to project forwardly from the front face of the brake head a greater distance than the inner end of the pad, in brake released position of the mechanism, as shown in Figs. 3 and 10. This greater projection of the outer end of the rubber pad 105 is desirable, since the rocker 29 swivels counterclockwise (Figs. 3 and -10) about the axis of its pivot support 112 as the brake shoe 30 is being automatically adjusted into continuous surface contact with the brake disc 31 upon application of the brake, and this action compresses the outer end section of the pad 105, while releasing the inner end section.

The rocker 29 (Figs. 3, 9l2) is in the general form of an arcuate or segmental flat plate having a pair of superposed aligned lugs 117 cast, forged or welded on the rear face thereof and provided with respective apertures 118 to receive the pivot pin 112 and to form thereby some of the joining parts of the swivel connection between the rocker and the brake head 28. This rocker 29 presents a flat front face 120 to receive the brake shoe 30 and a rear face 1121 of double slope to conform with the relatively sloping faces 108 of the pad 105 in continuous surface engagement therewith and is provided with holes 122 for securing said brake shoe thereto.

The lugs 117 on the rocker 29 engage opposite ends of the bearing block 110 on the brake head 28 to form a knuckle connection therewith and are pivotally connected to said brake head by the pivot pin 112 passing through the aligned holes 111 and 118 in said bearing block and said lugs. The pivot pin 112 has a head 123 at one end to seat on the top lug 117 and has a tapered section 124 at its lower end for the purpose to be described. A cotter pin 125 attached to the lower end of the pivot pin 112 prevents accidental withdrawal of the pin.

The section of the rear face 121 of the rocker 29 between the lugs 117 is pressed against the faces 108 of the pad 105 by the pivot pin 112, to maintain said pad under compression at all times, even when the brakes are not being applied.

The swivel connection between the rocker 29 and the brake head 28, and the resilient pad 105 with its double taper design, serve various functions. This construction serves to maintain the front face 120 of the rocker 29 parallel to and in aligumentw ith the braking face of the brake disc 31, even when the brake is not applied, and affords the necessary resiliency to permit this face to adjust itself automatically to cause the brake shoe 30 carshoe has become worn. "It should be noted, in this connection, that the leg 27 of the brake head lever 2.0 changes its angularity in relation to the braking face of the brake disc 31 as the lever moved between brake releasing and brake applying position. The front face of the lever leg 27 extends at a slight angle with the braking face of the brake disc 31 in brake releasing position of the brake head lever 28, as shown in Fig. 3, but the rubber pad 105, nevertheless, through its resilient action, maintains the front face 120 of the rocker 29 parallel to'the braking face of the brake disc 31. As the brake head lever 20 moves angularly about its pivot support 26 into brake applying position, the angularity of the front face of the lever leg 27 approaches parallelism with the braking face of the brake disc 31 and the brake shoe 30 coming in contact with the braking face of the brake disc at an angle is tilted thereby about the axis of the pivot pin 112 counterclockwise Figs. 3 and 10) against the resistance of the resilient pad 105, causing said shoe to adjust itself automatically into continuous surface contact with said braking face of the brake disc for effective braking action.

in fully brake applied position of the brake head lever 20, the sections of the front face of the brake head lever 28 on opposite sides of the center of the pad will .slope at equal angles with respect to the rear face 121 30.

. balanced forces.

aligned position shown in Fig. 3, with the front face 120 of the rocker still parallel to the braking face of thebrake disc 31.

Another function of the rubber pad 105 is to cushion the shock resulting from the sudden transmission of the brakes, so that parts of the brake mechanism do not receive the full impact of the shock.

Another important function of the rubber pad 105 is to hold the pivot pin 112 tight at all times, for when the pin is driven into the lugs 117 of the rocker 29 and into the bearing block of the brake head 28, the tapered lower end section 124 of the pin contacting the bearing block, cams the apertures in said lugs and said bearing block into alignment and compresses the rubber pad 105 sufiiciently to overcome vibration of the par-ts around the pin and to prevent or reduce thereby wear on the rocker 29, the brake head 28 and the pivot pin 112.

While the invention has been described with particular reference to a specific embodiment, it is to be understood that it is not to be limited thereto, but is to be construed broadly and restricted solely by the scope of the appended claims.

What is claimed is:

1. In a railway car truck, the combination of a pair of side frames, two pairs of coaxial car wheels supported on said side frames with the two axes of said wheels extending parallel between said side frames, brake discs rigid with said car wheels respectively for rotation therewith, and means for applying a brake to each of the brake discs comprising a lever pivoted at one end and carrying a brake head at the other end rigid therewith, a rocker having means for accommodating a brake shoe thereon, means supporting saidrocker on the brake head for pivotal action about an axis fixed in relation to said rocker and said brake head, said lever being supported for angular substantially horizontal movement to bring the shoe carried thereon into braking engagement with the corresponding brake disc, said brake head and said rocker presenting substantially flat confronting faces,

and a generally flat pad of elastomeric material independent of said supporting means and located between said confronting faces, the opposite faces of said pad being entirely covered by said confronting faces respectively, and said confronting faces being substantially parallel in normal position of said rocker when said brake lever is in brake released position, said pad extending on opposite sides of that plane of said axis transverse to said confronting faces, said rocker being adapted to pivot about said axis on the brake head from said normal position against the resistance of said pad as the lever moves angularly into braking position to cause said rocker to accommodate itself to the arcuate swing of the lever and thereby to efiect continuous surface engagement of the shoe with the brake disc, said pad by its resilient action returning said rocker in either rotative direction about its pivotal support on the brake head into said normal position when the lever moves into brake released position.

2. In a railway car truck, the combination as described in claim 1, wherein the means supporting the rocker on the brake head for pivotal action is a pivotal knuckle connection including a pair of aligned lugs extending across the top and bottom sides respectively of said pad.

3. In a railway car truck, the combination as described in claim 1, wherein the means supporting the rocker on the brake head for pivotal action includes a bearing block on said brake head, two lugs on said rocker at opposite ends of said block forming a knuckle connection with said bearing block and extending across the top and bottom sides respectively of said pad, and a pivot pin passing through said block and said lugs, said pad being .held under compression at all times to hold the parts of said knuckle connection tight against vibration.

4. In a railway car truck, the combination as described in claim 1, wherein the means supporting the rocker on the brake head for pivotal action includes a pivotal knuckle connection having apertured parts on said rocker and said brake head, and a pin passing through the apertures in said parts and having a tapering entry end by which said parts can be cammed relatively into alignment as said pivot pin is driven through said apertures and said pad can be compressed sufficiently to hold the parts of said connection tight against vibration at all times.

5. In a railway car truck, the combination as described in claim 1, wherein one of said confronting faces has a recess to receive said pad.

6. In a railway car truck, the combination of a pair of side frames, two pairs of coaxial car wheels supported on said side frames with the two axes of said wheels extending parallel between said side frames, brake discs rigid with said car wheels respectively for rotation therewith, and means for applying a brake to each of the brake discs comprising a lever pivoted at one end and carrying a brake head at the other end rigid therewith, a rocker having means for accommodating a brake shoe thereon, means supporting said rocker on the brake head for pivotal action about an axis fixed in relation to said rocker and said brake head, said lever being supported for angular substantially horizontal movement to bring the shoe carried thereon into braking engagement with the corresponding brake disc, and a pad of elastomeric material independent of said supporting means and located between the confronting faces of said brake head and said rocker, said pad extending on opposite sides of that plane of said axis transverse to said confronting faces, said pad comprising two opposed wedge sections integrally joined at their smaller ends in the intermediate region of the pad and presenting on one side of the pad a pair of sloping faces respectively converging towards said intermediate region, said pad being located between the confronting faces of the brake head and the rocker with said sloping faces engaging one of said confronting faces and in position to cause compressive forces to be applied to said pad across one or the other of its sloping faces as said rocker moves about its pivotal support on said brake head, according to the direction of pivotal movement of said rocker about the latter pivotal support, said rocker being adapted to pivot about said axis on the brake head from normal brake released position against the resistance of said pad as the lever moves angularly into braking position to cause said rocker to accommodate itself to the arcuate swing of the lever and thereby to effect continuous surface engagement of the shoe with the brake disc, said pad by its resilient action returning said rocker in either rotative direction about its pivotal support on the brake head into said normal position when the lever moves into brake released position.

References Iited in the file of this patent UNITED STATES PATENTS 510,407 Cochran et al. Dec. 12, 1893 614,628 Senderling Nov. 22, 1898 1,241,441 Pilcher Sept. 25, 1917 1,467,046 Kurtz Sept. 4, 1923 1,574,207 Schaefer Feb. 23, 1926 2,288,059 Williams June 30, 1942 2,348,078 Ledwinka May 2, 1944 2,527,072 Pogue Oct. 24, 1950 2,673,622 Coombes et al Mar. 30, 1954 2,673,623 Coombes Mar. 30, 1954 2,777,540 Bachman Jan. 15, 1957 FOREIGN PATENTS 7,382 Great Britain May 12, 1890 154,164 Great Britain May 18, 1922