US1942513A

US1942513A - Railway braking apparatus

Info

Publication number: US1942513A
Application number: US671866A
Authority: US
Inventors: John W Livingston
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1933-05-19
Filing date: 1933-05-19
Publication date: 1934-01-09
Anticipated expiration: 1951-01-09

Description

1934- J. w. uvmds-rou 2,

RAILWAY BRAKING APPARATUS Filed May 19, 1933 I l 2 45- I p 5 P! i P Z 3 L V I L V H 7050411 00 ofi 51 Fluid pf'lflgifip HIS ATTORNEY Patented Jan. Si, 1934 UNETED STATES PATNT OFFICE RAILWAY BRAKING APPARATUS Application May 19, 1933. Serial No. 671,866

17 Claims.

My invention relates to railway braking apparatus, and particularly to braking apparatus of the type comprising wheel-engaging braking bars located beside a track rail, and movable toward and away from the rail into braking and nonbraking positions. More particularly, my invention relates to apparatus of the type described in which the braking bars are arranged to be moved to their braking positions by a fluid pressure operated motor, and to be restored to their non-braking positions by suitable biasing means, such as gravity.

Specifically, my present invention is an improvement on apparatus of the type described and claimed in an application for Letters Patent of the United States filed by Herbert L. Bone,

on February 19, 1931, Serial No. 516,883, for Eailway braking apparatus.

One object of my invention'is the provision, in apparatus of the type described, of means for reducing the amount of fluid required for the normal operation of the braking apparatus.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view, partly diagrammatic and partly cross-sectioned, illustrating one form of apparatus embodying my invention, the parts being shown in the positions which they normally occupy when no cars are to be retarded. Fig. 2 is a view similar to Fig. 1,

but showing the parts in the positions which they occupy when it is desired to permit a locomotive having wide driving wheels to pass through the retarder without retardation.

Similar reference characters refer to similar parts in both views.

Referring to the drawing, the reference character 1 designates one tract: rail of a stretch of railway track which track rail, as here shown, is secured to a rail support 2 mounted on an adjacent pair of the usual crossties 3, only one crosstie being visible in the drawing. Associated with ne rail 1 is a car retarder comprising two braking bars A and A which extend parallel to the rail 1 on opposite sides of the rail. Each of these braking bars comprises, as usual, a brake beam 4 and a brake shoe 5'.

The braking bar A is arranged to be moved toward and away from the rail 1 by means of a lever 6 which is pivotally mounted at one end on a pivot pin 7 carried by the rail support 2, and the braking bar A is arranged to be moved to ward and away from the rail 1 by means of a lever 8 which is pivotally mounted intermediate its (Cl. 188-62) r ends on the pivot pin 7. The lever 6 is inclined upwardly and extends away from the rail 1, and

is provided in its upper surface with a recess 6 which receives the braking bar A The one end 8 of the lever 8 is likewise inclined upwardly and 0 extends away from the rail 1 at the opposite side of the rail from the lever 6, and the other end 8' of the lever 8 is inclined downwardly and extends away from the rail l'below the lever 6.

The end 8 of the lever 8 is provided in its upper 8"" 7 surface with a recess 8 similar to the recess 6* in the lever 6, which recess receives the braking bar A The parts are so arranged and so proportioned that if the outer or free ends of the

levers

6 and 8 are moved. apart, the braking bars will be moved toward the rails into their efiec tive or braking positions. When the braking bars occupy their braking positions, the brake shoes 5 will engage the opposite side faces of a N car wheel traversing rail 1, and will retard the speed of the car. The center of gravity of the lever 6 and braking bar A is considerably to the left of the pivot pin- 7, so that this lever will normally tend to rotate in a counter-clockwise direction about the pivot pin. Similarly, the center of gravity of the lever 8 and braking bar A is to the right of the pivot pin 7 so that this lever will normally tend to rotate in a clockwise direction about the pivot pin. It will be apparent, therefore, that when no force is applied to the 35 free ends of the

levers

6 and 8 to move them apart, v these levers will move toward each other, thereby moving the braking bars toward their inefiective or non-braking positions. H I For moving the levers apart, I provide appa- I ratus embodying my present invention, which apparatus I will now describe. As here shown, this apparatus comprises a main fluid pressure motor M and an auxiliary fluid pressure motor I M .v The cylinder 9 of motor M is operatively connected with the lever 6 by means of a pivot pin 10, a link 11, and a pivot pin 12, and the piston 13 of motor M is operatively connected with the arm 8 of lever 8 by means of a piston rod H 14,, an adjustable eyebolt 15, and a pivot pin 16. The cylinder 17 of motor M is pivotally supported in the lever 6 by means of trunnions 18, and the piston 19 of motor M is operatively connected with the link 11 and with cylinder 9 by means of I a piston rod 20 and the pivot pin 10. Fluid pressure may be admitted to the upper end of cylj inder 9 through a flexible pipe 21, and fluid pressure may be admitted to the upper end of cylinder 19 through a flexible pipe 22. A coil spring 23 surrounds piston rod 20 between piston 19 and the lower end of the cylinder 1'7, and constantly biases piston 19 to the position in which it engages the cylinder 17 at the upper end of the cylinder, which position of the piston I shall term its retracted position.

The parts are so proportioned that when fluid pressure is supplied to cylinder 17 of motor M as will normally be the case, the piston 19 ofthis motor will move downwardly to a projected position and will rotate link 11 and motor M to' the relative positions in which they are shown in Fig. 1, but that, when the supply of fluid pres"- sure to cylinder 1'7 is cut off and cyliiider' 9 vented to atmosphere, spring 23 will then move piston 19 upwardly to its retraeted post on, and will rotate link 11 and motof M to the relative positions in which they are shown in Fig. 2. The parts are further so proportioned that it fluid pressure is supplied to cylinder 9 of motor M when link 11 and motor M occupy the relative positions in" which they are shown in Fig. 1, the free ends of the

levers

6 and 8 will be moved apartfarenough to move the braking bars to their bra-king positions, but that, if the supply oi flii-id pressure to cylinder 9 is then out off and this cylinder is vented to atmosphere, thelevers S and 8 willrotate by gravity to such positions that the braking; bars will just clear car wheels ofordinary width; It is obvious that when piston 13- 80s of motor M occupies its upper position in cylind'er 9, the braking bars will be moved farther away from'the rails when the link 11 and motor M occupy the relative positions in which they are shown in Fig. 2 than when the link 11 ahd 85 motor M occupy the relative positions in which they are shown in Fig. 1, and the parts are still further so proportioned that if cylinder 9 of motor M is vented to atmosphere when lihk 11 andmotor M oecupy the relative positions showh main 2 aswill always be the case, the

levers

6 and 3 will rotate by gravity to the positions in whichtlie braking bars will clear the wide driving wheels of locomotives. v 4 4 A curved stop member 245 is formed integrally with the outer end of lever 6 and this stop e'omotor M from rotating past theposit'ioris' iii which they are shown in Fig} 1', I Theparts are so designed that when the link 11 and motor" M occupy the positions in which they are shown in Fig, 1, the toggie formed b'y'thc' linli and motor will be substantially on its dead center position, and it will be eppai-em; therefore, that no ponent of the force exerted by the motor M moving the braking bar's' t'o their braking posi- "tionswill be transmitted to the motor M It follows that the motor need eiiert only" cient force t'o move the levers 6 and 8', in oppo sition to then gravity bias, from the positions ,shown in Fig. 2 to the positions shown in Fig. 1,

so that this Iiiotof can be relatively small in size.

It will be readily understood that it is desirable to have the braking bars centered when they are in their open oif ineffective positions, in- -order to insure that the brake shoes will not en "'gag e the wheels of cars or locomotives which operates with the link 11 to prevent this link and sirable results. For the purpose of centering the braking bars when they are in their non-braking positions, I provide a roller stop 26 which is mounted in an upright or standard 27 secured to a supporting plate 3 and which cooperates with a stop surface 25 provided on the cylinder 9 of motor M Likewise, for the purpose of centering the braking bars when they are in their braking positions, I provide the arm 8 of the le-- ver 8' with a lug 28 which cooperates with a resilient stop 29 secured to the supporting plate 3 The manner in which the stop members just described cooperate will be obvious from the drawingyvithout further detailed description.

supply of fluid pressure to the motors M aiid M may be controlled in any suitable manher. As here shown, the supply of fluid pressure to motor M is controlled in part by a valve D which is secured to the stop member 24 and which is interposed in the flexible pipe 21 leading to the cylinder 9' ofmotor M The valve D is-biased' to a closed-position,- but is arranged-to become opened whenever li-ii k- 1-1- occupies the position in which it engagesthe stop member 24. It will be seen, therefore, that fluidpressure cannot be supplied tor-motor M unless the motor and link occupy the relative positions in which they are shown in Fi 1.

'I-he supply of; fluid pressure to motor M is also controlled by three magnet valves W, V

and W, which valves also control the supply of fluid pressure to motor M These valves are similar and each comprises avalve stem 30 biased to an upper position by means of a spring 31,

and provided with a winding 32- and an armature 34 and valve V with-apipe 35 which is constantly supplied with flu-id pressure,- usually air, from a suitablesource not shown in the drawing-. When valve V is deeherg-ized, however, as shown in the drawing, valve stem 30 of this valve is moved to its upper position by the associatedspring 31,

and pipe 2-1 isthen disconnected from; pipe 35. When valve V is energized, as shownin the drawing, valve stem 30 of this valve moves downwardly and connects boththe pipe 21 and a pipe 3'? lead ing to the valve V with atmosphere through a port 3?, but when this valve is deenergized, the pipes 37 and 21 become disconnected from atmosphere- When valve V is energized; valve stem 30' oi this valve moves downwardly and disconnects the pipe 22 from the pipe 3'1 and connects the pipe 22 with a pipe 38 leading to the pipe When valve V is deenergized, however pipe 22 becomes disconnected from pipe 38 and connected with pipe 3"(. It will be apparent, therefore, that when valve V is energized, fluid pressurewil-l be supg plied to cylinder 9 of motor M and when valve V is energized, fiuidpressure will be supplied to cylinder 17 ot motor M It will also be apparent that when valve V is energized, fluid pressure will be exhausted from cylinder 9 of motor M and 39 42} Gen-tact 39'40 is closed in the p posi- I! tion of the lever, the 50 position, and any position intermediate these two positions; contact 39-41 is closed in the 32 position of the lever, the p position, and any position intermediate these two positions; and contact 3942 is closed only in the p position of the lever.

Lever L will usually be located at a point remote from the braking apparatus, as in the control cabin of a classification car retarder system, and will be connected with the apparatus by means of line wires extending from the control cabin to the apparatus.

The operation of the apparatus as a whole is as follows: As shown in the drawing, lever L occupies its p position, which is the position which it normally occupies when no cars are to be retarded, and under these conditions, valve V is denergized, and the valves V and V are both energized. The circuit over which valve V is energized under these conditions may be traced from a suitable source here shown as a battery B through contact 39-40 of lever L, line wire 43, winding 32 of valve V wire 44, and line wire 45 back to battery B; while the circuit for valve V may be traced from battery B through contact 3941 of lever L, line wire 46, winding 32 of

valve V wires

47 and 44, and line wire 45 back to battery B. Since valve V is energized, fluid pressure is supplied to cylinder 17 of motor M and the link 11 and motor M are therefore held in the positions in which the link 11 engages the stop member 24. Furthermore, since valve V is deenergized, the supply of fluid pressure to cylinder 9 of motor M is cut off, and since valve V is energized, cylinder 9 is connected with atmosphere. The braking bars are therefore held by gravity in the positions in which they will just clear car wheels of ordinary width, the braking bars being centered in these positions by the stop rollers 26 cooperating with the stop surface 25 on the cylinder 9. r

I will now assume that the parts are in the positions shown in Fig. 1, and that it is desired to permit the passage of a locomotive through the 3 car retarder without retarding the speed of the locomotive. To do this, lever L is moved to its 12 position. This movement of the lever interrupts the circuit which was previously closed for valve V and valve V therefore becomes deenergized,

so that the valves V and V are then both deen- 'they are shown in Fig. 2, thereby permitting the braking bars to move by gravity from the positions where they will just clear car wheels of ordinary width, to the positions where they will clear the wide driving wheels of locomotives, in which latter positions they are shown in Fig. 2. t should be noted that when link 11 and motor M move to the positions shown in Fig. 2, valve D becomes closed so that it is then impossible for fluid pressure to be supplied to cylinder 9 of motor M I will now assume that the parts are in the positions in which they are shown in Fig. 1, and that it is desired to move the braking bars to their braking positions to retard the speed of a car passing through the braking apparatus. To

do this, lever L is moved to its p position. When this is done, valve V remains energized by virtue of the previously described circuit for this valve, and the link 11 and motor M are therefore held in the relative positions in which they are shown in Fig. 1. Furthermore, when lever L is moved to its 10 position, the previously described circuit for valve V is interrupted, and acircuit becomes completed for valve V this latter circuit passing from battery B through contact 39-42 of lever L, line wire 48, winding 32 of valve V and line wire 45 back to battery B. Valve V therefore becomes deenergized and disconnects cylinder 9 of motor M from atmosphere and valve V becomes energized and admits fluid pressure to cylinder 9 of motor M The fluid pressure thus supplied to cylinder 9 causes piston 13 to move downwardly to the position in which the stop lug 28 engages the resilient stop 29, after which cylinder 9 moves upwardly, thereby moving the braking bars to their braking positions.

One advantage of apparatus embodying my invention is that since the main fluid pressure motor M only moves the braking bars from the positions where they will just clear car wheels of ordinary width to their braking positions, the stroke of the piston of this motor may be made relatively short, and it will be apparent, therefore, that a smaller amount of fluid pressure'is required to operate the braking apparatus than would be necessary if the stroke of the piston had to be made long enough to move the braking bars from the positions in which they will clear the wide driving wheels of locomotives to their braking positions, as has heretofore generally been the case.

Another advantage of apparatus embodying my invention is that it can be built compactly.

Still another advantage of braking apparatus embodying my invention is that the arrangement of motor M is such that it is lowest with respect to the upper lever 6 when the braking apparatus is in its normal operating position, it being noted that motor M swings upwardly 120 about pivot 20 as the braking bars move toward the rail 1, so that the greatest height of the motor above the upper lever occurs when the upper lever is at its lowest position.

It should be particularly pointed out that while in describing my invention I have shown the main fluid pressure motor M connected with the

levers

6 and 8 by means of a link which is operated from one position to another position by an auxiliary fluid pressure motor in order to control the positions to which the braking bars are moved when no cars are to be retarded, my invention contemplates the use of any means for providing diflerent open positions of the braking bars by means of an auxiliary fluid pressure 1notor which changes the position of the main motor with respect to the upper or lower lever.

Although I have herein shown and described only one form of railway braking apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope or" the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I145 claim is:

1. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, 150

means including a first motor for moving said braking bars from the positions to which they are biased to positions in which they will just clear car wheels of ordinary width, and means including a second motor for moving said braking bars from the positions in which they will just clear car wheels of ordinary width to braking positions in which they will engage the wheels of a car traversing said track rail and retard the speed of the car.

2. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, two fluid pressure motors, means controlled bythe one motor for moving said braking bars from'the positions to which they are biased to the positions where they will just clear car wheels of ordinary width, and means controlled by the other motor for moving said braking bars from the positions where they will just clear car wheels of ordinary width to positions in which they will engage the wheels of a car traversing said track rail and retard the speed of the car.

3. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, two fluid pressure motors, means controlled by the one motor for normally preventing said braking bars from moving due to their bias past the position in which they will just clear car wheels of ordinary width but for at other times permitting said braking bars to move to their extreme biased position, and means controlled by the other motor for moving said braking bars from the positions where they will just clear car wheels of ordinary width to braking positions in which they will engage the wheels of a car traversing said track rail and retard the speed of the car.

4. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, two

" fiuid pressure motors, means controlled by the one motor for moving the braking bars from the positions to which they are biased to the positions in which they will just clear car wheels of ordinary width and for normally preventing said braking bars from moving due to their bias past the positions in which they will just clear car wheels of ordinary width, and means controlled by the other motor for moving said braking bars from the positions where they will just clear car wheels of ordinary width to the positions in which they will engage the wheels of a car traversing said track rail and retard the speed of the car.

5. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, means for moving said braking bars from the positions to which they are biased to positions in which they will just clear car wheels of ordinary width, and for normally preventing the braking bars from moving due to their bias past the positions where they will just clear car wheels or ordinary width, and other means for moving said braking bars from the positions in which they will just clear car wheels of ordinary width ibraking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, a first fluid pressure motor, means for supplying fluid pressure to said first motor, means effective when fiuid pressure is supplied to said first motor for moving the braking bars from the positions to which they are biased to the positions in which they will just clear car wheels of ordinary width and for subsequently preventing said braking bars from moving in the direction they are biased past the position where they will just clear car wheels of ordinary width, at second fluid pressure motor, means for supplying fluid'pressure to said second motor, means efiective when fluid pressure is supplied to said second motor for moving said bra-king bars from the positions where they will just clear car wheels of ordinary width to braking positions in which they will engage the opposite side faces oi the wheels of a car traversing said rail and retard the speed of the car, and means for preventing fluid pressure from being supplied to said second motor until after said braking bars have been moved by said first motor to the positions in which they will just clear car wheels of ordinary width.

'7. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and biased to positions in which they will clear the wide driving wheels of locomotives, a first fluid pressure motor, for supplying fluidpressure to said first motor, means erfective when fluid pressure is supplied to said first motor for moving the braking bars from the posi tions to which they are biased to the positions in which they will just clear car wheels of ordinary 110 width and for subsequently preventing saidbraking bars from moving in the direction they are biased past the position where they will just clear car wheels of ordinary width, a second fluid pressure motor, means for supplying fluid pres- 115 sure to said second motor, means effective when fluid pressure is supplied to said second motor for moving said braking bars from the positions where they will just clear car wheels or" ordinary width to braking positions in which they Will 1203 engage the opposite side faces of the wheels or a car traversing said rail and retard the speed of the car, and means controlled by said first motor for controlling the supply of fluid pressure to said second motor.

8. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two pivoted levers for supporting said two braking bars, a link pivotally connected at one end with one of' said levers, a main fluid pressure motor operatively connected with said two levers by means including link, and an auxiliary fluid pressure motor operatively connected with said link for varying the relative positions of said link and said motor relative to said lovers to move said levers to different positions from those which can be effected by operation of said first motor.

9. Railway braking apparatus comprising in combination with a track rail, two braking bars l iil located on opposite sides of the track rail, two pivoted levers each carrying one of sai braking bars, a link pivotally connected at one end with one of said levers, a main fluid pressure motor having a cylinder which is pivotally connected' directly with the free end of said link,

a piston in the cylinder of said first motor driving a piston rod which is connected directly with the other one of said levers, a second fluid pressure motor having a cylinder pivotallysupported in said one lever, and a piston in the cylinder of said second motor driving a piston rod which is pivotally connected directly with said link and with the cylinder of said first motor.

10. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two levers for supporting said braking bars, respectively, said levers being pivotally supported in such manner and the parts being so proportioned that said braking bars are biased by gravity to positions in which they will clear the wide driving wheels of locomotives, a link pivotally connected at one end with one lever, a cylinder pivotally attached to the free end of said link, a piston in said cylinder operatively connected with the other lever, the parts being so proportioned that when the axis of said link aligns with the axis of said cylinder movement of said piston from one end of its stroke to the other end oi its stroke will move said braking bars from the positions where they will just clear car wheels or" ordinary width to their braking positions, and means for at times rotating said link about its pivotal connection with said one lever to permit said braking bars to move to their biased positions.

11. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two levers for supporting said braking bars, respectively, said levers being pivotally supported in such manner and the being so proportioned that said braking bars are biased by ravity to positions in which they will clear the wide driving wheels of locomotives, a link pivotally connected at one end with one lever, a cylinder pivotally attached to the free end of said link, a piston in cylinder operatively connected with the other lever, the parts being so proportioned that when the axis of said link aligns with the axis or" said cylinder movement of said piston from one end of its stroke to the other end of its stroke will move said braking bars from the positions where they will just clear car wheels of ordinary width to their brakingpositions, mean for normally rotating said link and said cylinder to the relative positions in which their axes align, and means for at other times rotating said link and cylinder to other relative positions.

12. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, t v0 levers for supporting said braking bars, respectively, said levers being pivotally supported in such manner and the parts being so proportioned that said bars are biased by gravity to positions in which they will clear the wide driving wheels of locomotives, a link pivotally connected at one end with one lever, a cylinder pivotally attach d to the free end of said link, a piston in said 0, inder operatively connected with the other lever, the parts being so proportioned that when the axis of said link aligns with the axis of said cylinder movement of said piston from one end of its stroke to the other end of its stroke wiil move said braking bars from the positions where they will just clear car wheels of ordinary width to their braking positions, spring means for biasing said link and cylinder to relative positions in which their axes are out of alignment, and a fluid pressure motor for rotating said link and cylinder in opposition to the bias of said spring means to the relative positions in which the axis of said link and the axis of said motor are in substantial alignment.

13. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two substantially horizontal levers pivotally supported beneath the track rail and one supporting each or" said braking bars in such manner that rotation of said levers about their pivots will rotate said braking bars toward or away from the track rail, the parts being so proportioned that said braking bars are biased by gravity to positions in which they will clear the wide driving wheels of locomotives, a first fluid pressure motor operatively connected with said two levers for moving said braking bars from the positions to which they are biased toward the track rail to positions in which they will just clear car wheels of ordinary width and for at times preentlng said braking bars from moving in the direction they are biased past the positions where they will clear car wheels of ordinary width, and a second fluid pressure motor operatively connected with said levers for moving said braking bars from the positions in which they will just clear car wheels of ordinary width to positions in which they will engage the wheels of a car traversing said track rail and retard the speed of the car.

14. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, a first lever for supporting one of said braking bars, said first lever being pivotally mounted atone end and havin its free end inclined upwardly and extending away from said track rail, a second lever pivotally mounted intermediate its ends and having one end inclined upwardly on the opposite side of the rail from said first lever for supporting the other braking bar and having its other end inclined downwardly and extending away from the rail below the free end of said first lever, a link pivotally connected at one end with said first lever adjacent its free end, a main fluid pressure motor having its cylinder pivoti,

ally connected directly with the free end of said link, a piston in the cylinder of said main motor driving a piston rod which is pivotally connected with the free end of the other lever, the parts being so proportioned that when the axis of said link aligns with the axis of said main motor movement of said piston from one end of its stroke to the other will move said braking bars from the positions where they will just clear car wheels of ordinary width to braking positions in which they will engage the opposite side faces of car wheels and retard the speed of the car, an auxiliary fluid pressure motor having its cylinder pivotally supported in said one lever, a piston in the cylinder of said auxiliary motor driving a piston rod which is connected with said link and the cylinder of said main motor at their point of connection in such manner that when said last mentioned piston is in its projected position said link and said main motor will be held in the relative positions in which their axes align, and a spring in the cylinder of said auxiliary motor biasing the piston of said auxliary motor to a retracted postion, the parts being so designed that movement of the piston of said auxiliary motor from its projected position to its retracted position will rotate said link and said main motor to positions in which their axes are out of alignment, thereby causing sufficient additional movement of said braking bars away from the track rail to permit them to clear car wheels of ordinary width.

15. Railway braking apparatus comprising two braking bars located on opposite sides or" a track rail, a first lever for supporting one of said braking bars, said first lever being pivotally mounted at one end and having its free end inclined upwardly and extending away from said track rail, a second lever pivotally mounted intermediate its ends and having one end inclined upwardly on the opposite side of the rail from said first lever for supporting the other braking bar and having its other end inclined downwardly and extending away from the rail below the free end of said first lever, a link pivotally connected at one end with said first lever adjacent its free end, a main fluid pressure motor having its cylinder pivotally connected directly with the free end of said link, a piston in the cylinder of said main motor driving a piston rod which is pivotally connected with the free end of the other lever, an auxiliary fluid pressure motor having its cylinder pivotally supported in said one lever, a piston in the cylinder of said auxiliary motor driving a piston rod which is connected with said link and the cylinder of said main motor at their point of connection in such manner that when said last mentioned piston is in its projected position said link and said main motor will be held in the relative positions in which their axes align, but that when said last mentioned piston occupies its projected position, said link and said main motor will then be rotated to positions in which their axes are disposed at an acute angle, and a spring in said auxiliary 'motor for biasing the piston of, this motor to its pies its projected position said braking bars will be moved toward the track rails to braking positions in which they will engage the opposite side faces of car wheels traversing said track rail and retard the speed of the car but that when the supply of fluid pressure to said main motor is cut off said braking bars will move by gravity to the positions to which they will just clear car wheels of ordinary width or to the positions to which they are biased according as the position of said auxiliary motor then occupies its projected or retracted position.

16. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two pivoted levers for supporting said braking bars, a link pivotally connected at one end with one of said levers, amotor device operatively connected with the other end of said link and with the remaining levers for at times operating said levers, and means for rotating said link about its pivotal connection to diiierent positions.

'17. Railway braking apparatus comprising two braking bars located on opposite sides of atrack rail and biased to positions in which they will clear the wide driving wheels of locomotives, means including a first motor for moving said braking bars from the positions to which they are biased to positions in which they will just clear car wheels of ordinary width, means including a second motor for moving said braking bars from the positions in which they will just clear car wheels of ordinary width to braking positions in which they will engage the wheels or" a car travers'ing said track rail and retard the speed or" the car, and means for centering said braking bars relative to said track rail in all three positions of said braking bars.

JOHN W. LIVINGSTON.

its