US2014551A - Railway braking apparatus - Google Patents

Description

Sept 17,1935. H. L. BONE ET AL. ZMMESK RAILWAY BRAKING APPARATUS Filed Nov. 15, 1954 4 2 Sheds-Sheet 1 IN VENT ORS Herbert. L .Bone and By Harold C.CZ0IL ZS@I2 THEIR ATTORNEY W, 13. v H. L. BONE-ET AL fi fi RAILWAY BRAKI NG APPARATUS Filed Nov. 15, 1954 2 Sheets-Sheet 2 IN VENT 0R8 Herba L .80129 and y Harold 6. CZaasgm THEIR ATTORNEY Patented Sept. 17, 1935 UNHTED STATES PATENT orrics RAILWAY BRAKING APPARATUS 'Herbert L. Bone, Pittsburgh,

and Harold C.

Application November 15, 1934, Serial No. 753,185

16 Claims.

Our invention relates to railway braking apparatus, and particularly to braking apparatus of the type comprising wheel-engaging braking bars extending parallel to a track rail and movable toward and away from the rail into braking and non-braking positions.

More particularly, our present invention relates to apparatus of the type described and claimed in Letters Patent of the United States No. 1,927,201, granted to Herbert L. Bone, on September 19, 1933, and'has for an object the provision of means for improving certain features of the apparatus shown in the said Bone patent.

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

In the accompanying drawings, Fig. 1 is a View, partly in section and partly in elevation, showing one form of braking apparatus embodying our invention. Figs. 2 and 3 are left-hand side and right-hand side views, respectively, of the apparatus shown in Fig. 2.

Similar reference characters refer to similar parts in all three views.

Referring to the drawings, the reference charactor I designates one track rail of a stretch of railway track, which track rail, as here shown, is secured to two rail supports 2 and '3 (Fig. 2) mounted respectively on two adjacent cross-ties i. Associated with'the rail I are two braking bars A and A which extend parallel to the rail I on opposite sides of the rail. Each of these braking bars comprises as usual, a brake beam 5 and a brake shoe 6.

The braking bar A is arranged to be moved toward and away from the rail I by means of a lever i which is pivotally supported at one end on a pivot pin 8 mounted in the rail supports 2 and 3 directly below the rail I, and the braking bar A is arranged to be moved toward and away from the rail I by means of a lever 9 which is pivotally mounted intermediate its ends on the pivot pin 3. The lever I is inclined upwardly and extends away from the rail I and is provided in its upper surface with a recess '1 which receives' the braking bar A The one end 9 of the lever 9 is likewise inclined upwardly and extends away from the rail I at the side of the rail opposite to the lever l, and the other end 9 of the lever 9 is inclined downwardly and extends away from the rail ibelow the lever I. The end 9 of the lever 9 is provided in its upper surface with a recess 9 similar to the recess l in the lever i, which recess receives the braking bar A The braking bars A and A are adjustably fastened to the associated levers by suitable fastening means including hold-down bolts Ill and adjusting bolts I. These fastening means form no part of our present invention, and are described and claimed in a copending application for Letters Patent of the United States, Serial No. 753,184, filed on the same date and under the same title as the present application, by Herbert L. Bone, one of the co-inventors of the present invention. Since these fastening means form no part of our present invention and are described in the copending Bone application just referred to, it is deemed unnecessary to describe them herein.

The outer or free end of the lever I is pivotally connected at point I2 with the cylinder I3 of a fluid pressure motor M, and the end 9 of the lever 9 is pivotally connected at point It with a piston I5 operating incylinder IS. The cylinder I3 is provided with an inlet port It through which fluid pressure, usually air, may at times be admitt-ed to the upper end of this cylinder, thereby forcing the piston I5 downwardly in the cylinder and so spreading the outer or free ends of the levers I and 9 apart.

The portion of the apparatus thus far described forms no part of our present invention except in so far as it is used in combination with the apparatus embodying our invention, and its operation, briefly described, is as follows: The parts of the apparatus are so proportioned that lever I is biased by gravity to swing in a counter-clockwise direction, and lever9 is biased by gravity to swing in a clockwise direction. It will be apparent, therefore, that when cylinder I3 is disconnected from the source of fluid pressure and is vented to atmosphere, the levers at the ends which are, connected with the motor M will swing toward each other to the relative positions in which the piston I5 is at the upper end of the cylinder IE5 and will thus move the braking bars away from the rail I toward their ineffective or nonbraking positions in which latter positions they are out of engagement with the wheels of a car or locomotive traversing rail I. When, however, cylinder It of motor M is supplied with fluid pressure, lever i will be swung in a clockwise direction, and lever B will be swung in a counter-clockwise direction, thereby moving the braking bars toward the rail I to their effective or braking positions. When the braking bars occupy their brakingfpositions, the brake shoes 6 will engage the opposite side faces of a car wheel traversing rail I, and will retard the speed of the car.

' It will be apparent that it is desirable to have the braking bars A and A accurately positioned with respect; to the rail I when the braking bars are in their open or ineffective positions, in order to insure that the brake shoes 6 will not engage the wheels of cars or locomotives which should not be retarded while passing the braking apparatus, and it will also be apparent that it is likewise desirable to have the braking bars accurately positioned with respect to the rail I when the braking bars are moved to their effective or braking positions, so that cars which are to be retarded may enter the braking apparatus smoothly and without danger of derailment. For accomplishing these desirable results, we provide positioning means embodying our present invention which positioning means also perform the additional function of assisting the force of gravity in returning the braking bar A to its open position after it has been moved to its closed position, as will appear more fully hereinafter.

Referring now again to the drawings, our positioning means include two resilient stop units U and U which are associated with lever I, and a spring unit U which is associated with lever 9. The stop units U and U are similar, .and are secured to lugs I7 and I8 formed on opposite sides of lever I, as best seen in Fig. 2. Each stop unit comprises a nut I 9 screwed onto the lower end of a bolt 20 which extends downwardly with some clearance through a hole 45 provided in the associated lug I! or I8 and through a boss 46 which surrounds the lower end of the hole, and a spring 2I which surrounds the upper end of the nut I9 and the lower end of the bolt 20, and which engages at one end the under side of the associated lug I! or I 8, and at the other end a flange I 9 provided on the associated nut I9.

The stop units U and U cooperate at their lower ends with fixed stops 2 and 3 provided on the rail supports 2 and 3. The springs 2| of the units U and U are so designed, and these units are so adjusted, that, when the lever I has rotated in a counter-clockwise direction, due to its bias, to the position in which the braking bar A occupies the desired non-braking position with respect to the rail I, these units will engage the associated fixed stops and prevent further rotation of the lever I. The springs of these units are further so proportioned that, if a car becomes derailed for any reason so that its wheels ride up onto the braking bar A the springs of these units will not deflect any appreciable amount, but that, if, when the braking bar A occupies its non-braking position, a locomotive having unusually wide gauge wheels enters the retarder, these springs will deflect and permit sufficient additional movement of the braking bars to prevent damage to the braking apparatus.

The spring assembly U associated with the lever 9 is housed in a cylinder 25 which is cast integrally with the lever 9 on the underside of the arm 9 and which is partially closed at its lower end by an end plate 26 which is bolted to the cylinder 25 by means of T-headed machine bolts 24. The end plat-e 26 has formed therein a hole 21 which is in axial alignment with the cylinder 25, and slidably mounted in this hole is a sleeve 28 provided at its upper end with an annular flange 28 which cooperates with the end plate 26 in a manner which will be made clear hereinafter. A spring bolt 29 extends into the cylinder 25 through the sleeve 28 with suflicient clearance to permit the bolt to slide freely in the sleeve, and this bolt is provided on the inside of the cylinder with an enlarged shank portion 29, the lower end of springs 30 and 3|.

which forms a shoulder 29 which cooperates with the flange 28 on the sleeve 28 for purposes which will also be made clear hereinafter. The spring bolt is further provided on the inside of the cylinder 25 with a circular head 29 having a diameter which is just a little smaller than the diameter of the cylinder 25, and surrounding the spring bolt between the head 29 and the flange 28 on the sleeve 28, and between the head 29 and the end plate 26, respectively, are two concentric coil The lower end of the spring bolt 29 extends downwardly through a lateral slot 33 formed in an angle bracket 33, and is secured to the angle bracket in such manner that the bolt is free to move along the slot 33 in response to rotation of the lever 9, and that a limited amount of vertical movement of the bolt with respect to the angle bracket is permitted. As here illustrated, the means for securing the bolt to the angle bracket comprises two nuts 34 and 35 which are screwed onto the screw-threaded lower end of the bolt, and which have abutting portions of reduced diameter which extend into the slot 33 with suflicient clearance to permit the desired movement of the bolt. The nuts 34 and 35 are locked in place on the bolt 29 by means of cotter keys 31 in the usual and well-known manner. The angle bracket 33 spans the space between the ties 4 directly below the cylinder 25, and rests at its ends on the adjacent feet of the rail supports 2 and 3. It is secured to the rail supports by means of two bolts 49 which secure the rail supports to the ties and, in order to facilitate the ready removal of the angle bracket, the angle bracket is provided with laterally extending slots II which receive the bolts. The under side of the angle bracket adjacent the slot 33 is in the form of an arc to facilitate the movement of the bolt 29 in response to rotation of the lever 9 without excessive friction between the nut 35 and the angle bracket.

The spring 3| is assembled in the cylinder 25 with an initial compression and the nuts 34 and 35 on the bolt 29 are so adjusted that, when the lever 9 is rotated to the position in which the braking bar A occupies the desired non-braking position, the head of the bolt 29 will be spaced a short distance from a depending stop 32 which is provided on the arm 9 of lever 9 at the upper end of the cylinder 25. It will be apparent, therefore, that the spring 3I constantly biases the lever 9 toward the position in which the head of the bolt'29 engages the stop 32, and that any movement of the lever 9 in the direction to move the braking bar A from its non-braking position to its braking position will act through the end plate 26 to compress the spring 3I. The spring 38 is also assembled into the cylinder 25 with an initial compression and the sleeve 28 with which the lower end of this spring cooperates is so designed that the end plate 26 will move into engagement with the flange 28 of this sleeve and compress the spring 30 beyond its initial compression when and only when the braking bar A is moved closer to the rail I than the desired braking position. The springs 30 and 3I are so proportioned that when the braking bars have been rotated to their desired braking positions, the force due to the amount of compression which then exists in the spring 3I plus that due to the initial compression of. the spring 30 will be sufficient to overcome the counter-clockwise rotational tendency of the complete lever assembly. The extreme position toward the rail to which the braking bar A can be moved in response to rotation of the lever 9 is limited by the flange 28 of the sleeve 28 moving into engagement with the shoulder 29 formed on the bolt 29.

' The operation of the apparatus as a whole is as follows: When cylinder I3 of motor M is vented to atmosphere to permit the braking bars to move to their ineffective or non-braking positions, the lever 'I will first rotate about the pivot pin 8 in a counter-clockwise direction in the manner previously described until the stop units U and U move into engagement with the associated fixed stops 2 and 3 after which the lever 9 will rotate about the pivot pin -8 in a clockwise direction until the piston I5 moves into engagement with the upper end of cylinder I3 of motor M. When in this position the head 29 of bolt 29 will be spaced 2. short distance from stop 32. As was previously pointed out, the stop units U and U are so adjusted and so designed that when these stop units are in engagement with the associated fixed stops 2 and 3 the braking bar A will occupy the desired non-braking position with respect to the rail I; and the parts of the apparatus are so proportioned that when the stop units U and U are engaging the associated fixed stops and the piston I5 of motor M is engaging the upper end of cylinder. I 3, the braking bar A will occupy the desired non-braking position with respect to the rail I.

When fluid pressure is supplied to cylinder I3 of motor M to move the braking bars to their effective or braking positions, lever 9 will first rotate in a counter-clockwise direction until the end plate 26 has moved into engagement with flange 28 on sleeve 28, after which further rotation ofv the lever 9 will be prevented by the springs, and the lever I will then rotate in a clockwise direction until piston I 5 reaches the lower end of its stroke. The parts are so proportioned that when the levers I and 9 have been rotated to the positions just described, the braking bars A and A will then occupy the desired braking positions with respect to therail I. It should be noted that if, for any reason, the lever I should develop more resistance to rotation under the conditions just described than is normally the case, the lever 9 will then first rotate to the position where the sleeve 28 is moved into engagement with the shoulder 29 on'the bolt 29 by the end plate 26 engaging the flange 28 of the sleeve, whereupon further rotation of this lever will positively be prevented, and the lever I will then rotate in a clockwise direction to move the braking bar 'A to its braking position. j

If, when the braking bars are in their nonbraking'positions, a locomotive having exceptionally narrow gauge driving wheels should pass through the braking apparatus and tend to force the braking bar A farther away from the rail, the lever 9 will rotate in a clockwise direction until it takes up the clearance which previously existed between the head 29 of the spring bolt 29'and the stop 32, and the spring bolt 29 will then drop down and take up the clearance which normally exists betweenthe nut 34 and the topsurface of angle bracket 33. This rotation of the lever 9 willcause corresponding rotation of the lever I, since the piston l5 of motor M under these conditions will be at theupper end of its stroke and the force which is exerted on lever 9 by the braking-bar will be transmitted through the lever 9 and the piston I5 and cylinder I3 of. motor M to the lever I. It follows that no damage will result to the re tarder under these conditions.

Should'a locomotive with exceptionally wide gauge driving wheels tend to drive the outside braking bar A} further away from the rail than its non-braking position, the springs of the units U and U 'will deflect in the manner previously described and permit the necessary movement. When the outside braking bar A is pushed back in this manner, the lever and cylinder assembly will rotate as a whole in a counter-clockwise direction, the maximum amount of rotation in this direction being reached when the springs 2| of the stop units U and U are compressed solid.

If, for some reason, the braking bar A should tend to move closer to the rail I than its normal braking position while a car is being retarded, as might happen if the wheels of the car were widely spaced on the axles 01' the retarder was out of adjustment, both springs 30 and 3| of the spring unit U will become compressed and will permit the lever 9 to rotate without damage to the retarder, the maximum amount of rotation of the lever in this direction being limited by the upper surface of the flange 28 on sleeve 28 coming in contact with the shoulder 29 on the spring bolt 29 in the manner previously pointed out. This same action of the apparatus might also occur if a car while being retarded, were raised on the outside braking bar A because it will be noted that when this occurs, the stop units U and U are out of engagement with the associated fixed stops 2 and 3 and the tendency for the complete lever and cylinder assembly to rotate in a counter-clockwise direction is then increased due to the weight of the car. 7

It should be pointed out that while as shown in the drawings the braking bars are operated by only one lever and cylinder assembly, in actual practice these braking bars will be operated by a plurality of similar assemblies disposed along the bars substantially in accordance with the disclosure of the two Bone applications referred to hereinbefore.

One advantage of positioning means embodying our invention is that these positioning means are readily accessible at all times for inspection and repair. Another advantage of positioning means embodying our invention is that they are inexpensive tomanufacture and highly efiicient for their intended purpose.

Still another advantage of positioning means embodying our invention is that they provide a compact arrangement which does not increase the overall height of the braking apparatus.

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

Having thus described our invention, what we claim is:

, 1. In combination, a rail support, a track rail mounted on said support, two braking bars located on opposite sides of said track rail and movable toward and away from the rail into braking and non-braking positions, two levers pivoted in said rail support and one supporting each of said braking bars in such manner that said braking bars are biased by gravity to swing away from the rail toward their non-braking positions, resilient means secured to the one lever and cooperating with fixed means formed on said rail support in such manner that'when the braking bar associated with said one lever has moved away from the rail to its non-braking position due to its bias said resilient means will engage said fixed means and prevent further movement of such braking bar due to its bias, and a fluid pressure motor connected with said two levers for operating said levers to move said braking bars to their braking positions, the parts being so proportioned that when said resilient means is engaging said fixed means and the piston of said fluid pressure motor is in its retracted position, the braking bar attached to the other lever will occupy its non-braking position.

2. In combination, two rail supports, a track rail mounted on said supports, two braking bars located on opposite sides of said track rail and movable toward and away from the rail into braking and non-braking positions, a pivot pin mounted at its ends in said two rail supports, 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, the parts being so proportioned that said levers are biased by gravity to swing in directions to move said braking bars to their nonbraking positions, a fluid pressure motor connected between the free end of said first lever and said other end of said second lever for operating said levers to move said braking bars to their braking positions, the combination with the aforementioned instrumentalities of two lugs located on opposite sides of said first lever, two resilient stop units one secured to each of said lugs and each including a spring and means for adjusting the compression of said spring, and two fixed stops secured to said two rail supports respectively and each cooperating with said resilient stop units for limiting the rotation of said first lever due to its bias.

3. In combination, two rail supports, a track rail mounted on said supports, two braking bars located on opposite sides of said track rail and movable toward and away from the rail into braking and non-braking positions, a pivot pin mounted at its ends in said two rail supports, 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, the parts being so proportioned that said levers are biased by gravity to swing in directions to move said braking bars to their non-braking positions, a fluid pressure motor connected between the free end of said first lever and said other end of said second lever for operating said levers to move said braking bars to their braking positions, the combination with the aforementioned instrumentalities of two lugs located on opposite sides of said first lever, two resilient stop units one secured to each of said lugs and each including a spring and means for adjusting the compression of said spring, and two fixed stops secured to said two rail supports respectively and each cooperating with said resilient stop units, the, parts being so proportioned that when said first lever has been rotated by its bias to the position in which said one braking bar occupies its non-braking position said stop units will engage said fixed stops and prevent further rotation of said one lever by its bias andthat .5

rail mounted on said supports, two braking bars 15 located on opposite sides of said track rail and movable toward and away from the rail into braking and non-braking positions, a pivot pin mounted at its ends in said two rail supports, 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, the parts being so proportioned that said levers are biased by gravity to swing in directions to move said braking bars to their non-braking positions, a fluid pressure motor connected between the free end of said first lever and said other end of said second lever for operating said levers to move said braking bars to their braking positions, the combination with the aforementioned instrumentalities of two lugs located on opposite sides of said first lever, two resilient stop units one secured to each of said lugs and each including a spring and means for adjusting the compression of said spring, and two fixed stops secured to said two rail supports respectively and each cooperating with said resilient stop units, said stop units being so proportioned that they will move into engagement with said fixed stops when said first lever is rotated to the position in which said one braking bar occupies its non-braking position and will prevent further rotation of said one lever in the direction to move said one braking bar away from the rail except in the event said one braking bar is then engaged by the wheels of a vehicle having unusually wide gauge wheels.

5. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two pivoted levers supporting said two braking bars respectively, a fluid pressure motor for operating the levers to move said braking bars toward the track rail, a cylinder attached to one 00 of said levers to move therewith, and means including said cylinder for maintaining said braking bars in predetermined relative positions with respect to'said track rail when said levers are operated by said motor to move said braking bars toward the track rail.

6. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two pivoted levers supporting said two braking bars respectively, a fluid pressure motor for operating the levers to move said braking bars toward the track rail, a cylinder attached to one of said levers to move therewith, and resilient means cooperating with said cylinder for positioning said braking bars with respect tothe track rails when said levers are operated by said motor.

7. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail, two pivoted levers supporting said two braking bars respectively, a fluid pressure motor for operating the levers to move said braking bars toward the track rail, said levers being biased by gravity to move said braking bars away from the track rail, 2, cylinder attached to one of said levers to move therewith, an end plate attached to one end of said cylinder and provided with a hole which aligns axially with said cylinder, a spring bolt extending into said cylinder through said hole and provided on the inside of said cylinder with a head, a spring surrounding said bolt within said cylinder between said head and said end plate, and means for anchoring said bolt at its outer end in such manner that movement of said one lever in the direction to move said associated braking bar toward the track rail will compress said spring.

8. Railway braking apparatus comprising two braking bars located on opposite sides of a track rail and adapted to be moved toward and away from the rail into braking and non-braking positions, two levers one for supporting each of said braking bars, said levers being pivotally mounted for rotation about a common axis in such manner that said braking bars are biased by gravity to move away from the track rail, a fluid pressure motor connected between said levers in such manner that when fluid pressure is supplied to said motor said motor will operate said levers to move said braking bars toward the track rail, a resilient stop unit secured to the one lever and cooperating with a fixed stop for positioning said braking bars with respect to the track rail when said fluid pressure motor is vented to atmosphere, a cylinder secured to the other lever, and resilient means cooperating with said cylinder for positioning said braking bars with respect to the track rail when said levers are operated by said motor.

9. 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 at one end and having itsfree 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, the parts being so proportioned that said levers'are biased by gravity to the positions in which said braking bars occupy their non-braking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, resilient means secured to the one lever for controlling the nonbraking positions of the braking bars with respect to said track rail, and resilient means secured to the other lever for controlling the braking positions of the braking bars with respect to the track rail.

10. 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 having its free end inclined uping positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, a cylinder cast integral with said one end of said second lever and having its lower end partly closed by an end plate provided with a hole which aligns axially with said cylinder, a sleeve slidably mounted in said hole and provided on the inside of said cylinder with a flange which is larger than said hole, a bolt slidably mounted in said sleeve and provided on the inside of said cylinder with a head, a first spring surrounding said bolt within said cylinder between said head and said sleeve and provided with an initial compression, a second spring surrounding said first spring between said head and said end plate and provided with an initial compression, means for anchoring the lower end of said bolt in such manner that said bolt is free to swing in response to rotation of said second lever but that rotation of said second lever in the direction to move the associated braking bar toward its braking position will cause said bolt to slide in said sleeve and compress said second spring, and means on said bolt adjusted to hold said sleeve in such position on said bolt that said end plate will move into engagement with said flange and compress said first spring when and only when said second lever has been moved by said fluid pressure motor past the position where the associated braking baroccupies its braking position.

11. 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 at one end 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, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their non-braking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, a cylinder cast integral with said one end of said second lever and having its lower end partly closed by an end plate provided with a hole which aligns axially with said cylinder, a sleeve slidably mounted in said hole and provided on the inside of said cylinder with a flange which is larger than said hole, a bolt slidably mounted in said sleeve and provided on the inside of said cylinder with a head, a first spring surrounding said bolt within said cylinder between said head and said sleeve and provided with an initial compression, at second spring surrounding said first spring between said head and said end plate and provided with an initial compression, a fixed angle bar provided with a slot which receives the lower end of said bolt, and two nuts screwed onto the lower end of said bolt and provided with confronting portions of reduced diameter which extend loosely into said slot in such manner that said bolt is free to move along said slot and that a limited amount of vertical movement of said bolt with respect to said angle bar is permitted, the parts being so proportioned that any rotation of said second lever in a the direction to move the associated braking bar toward the track rail will compress said second spring, and that rotation of said second lever by said motor past the position in which said braking bar occupies its braking position will cause said end plate to engage the flange on said sleeve and slide said sleeve along said bolt in a manner to compress said first spring.

12. 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 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, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their non-braking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, two lugs secured to opposite sides of said first lever and each provided with a hole, two bolts one extending downwardly through each hole with some clearance, two nuts one adjustably screwed onto the lower end of each bolt, two springs one disposed on each bolt between each lug and the associated nut, and two fixed stops one cooperating with each nut, the parts being so proportioned that when said first lever has been rotated by its bias to the position in which the associated braking bar occupies its non-braking position said nuts will engage the associated stop and prevent additional rotation of said first lever by its bias but that if when said nuts are engaging said stops the braking bar associated with said first lever is engaged by the wide driving wheels of a locomotive said springs will deflect and permit additional rotation of said first lever.

13. 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 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 brakirg bar and having its other end inclined downwardly and extending away from the rail below the free end of said first lever, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their nonbraking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said" levers in directions to move said braking bars to their braking positions, resilient stop units attached to said first lever and cooperating with pies its non-brakingposition and will prevent further rotation of said first lever in the direction to move said braking bar away from the rail except when such braking bar is forced away from the rail by the wide driving wheels of a locomotive, the parts being so proportioned that 1 when said stop units are engaging the associated fixed stops and the piston of said motor is in its retracted position said second lever will be ro-' tated to a position in which the braking bar carried thereby occupies its non-braking position. 1

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 at one end and having its free end inclinedup- 2 wardly 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 2 having its other end inclined downwardly and extending away from the rail below the free end of said first lever, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their 3 non-braking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, resilient means 3 associated with said first lever for positioning said braking bars with'respect to said track rail when said fluid pressure motor is vented to atmosphere, a cylinder cast integral with said one end of said second lever and having its lower 4 end partly closed by an end plate provided'with a hole which aligns axially with said cylinder, a sleeve slidably'mounted in said hole and provided on the inside of said cylinder with a flange which is larger than said hole, a bolt slidably 4 mounted in said sleeve and provided on the inside of said cylinder with a head, a first spring surrounding said bolt within said cylinder between said head and said sleeve and provided with an initial compression, a second spring sur- 5 rounding said first spring between said head and. said end plate and provided with an initial compression, a fixed angle bar provided with a slot which receives the lower end of said bolt, two nuts screwed onto the lower end of said bolt and 5 provided with confronting portions of reduced diameter which extend loosely into said slot in such manner that said bolt is free to move along said slot and that a limited'amount of vertical movement of said'bolt with respect to said angle bar is permitted, and a fixed stop member provided on said one end of said second lever within said cylinder and adapted to cooperate with said bolt, the parts being so proportioned that if the braking bar attached to said second lever is moved away'from the rail past its non-braking position by a wide car wheel said fixed stop member will cooperate with the head of said bolt to limit the movement of the said braking bar and that if the braking bar attached to said second lever is moved toward the rail past its braking position said end plate will engage the flange on said sleeve and cause said sleeve to compress said first spring.

15. Railway braking apparatus comprising two 7 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 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, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their non-braking positions, a fiuid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, a cylinder cast integral with said one end of said second lever and having its lower end partly closed by an end plate provided with a hole which aligns axially with said cylinder, a sleeve slidably mounted in said hole and provided on the inside of said cylinder with a flange which is larger than said hole, a bolt slidably mounted on said sleeve and provided on the inside of said cylinder with a head, a first spring surrounding said bolt within said cylinder between said headland said sleeve and provided with an initial compression, a second spring surrounding said first spring between said head and said end plate and provided with an initial compression, a fixed angle bar provided with a slot which receives the lower end of said bolt, and two nuts screwed onto the lower end of said bolt and provided with confronting portions of reduced diameter which extend loosely into said slot in such manner that said bolt is free to move along said slot and that a limited amount of vertical movement of said bolt with respect to said angle bar is permitted, the parts being so proportioned that when said second lever is moved by said motor to the position in which j the braking bar carried thereby occupies its braking position said springs will exert a force on said lever which is sufficient to overcome any rotational tendency of the lever and motor assembly due to gravity.

16. 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 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, the parts being so proportioned that said levers are biased by gravity to the positions in which said braking bars occupy their nonbraking positions, a fluid pressure motor connected between the free end of said first lever and the other end of said second lever for rotating said levers in directions to move said braking bars to their braking positions, a cylinder cast integral with said one end of said second lever and having its lower end partly closed by an end plate provided with a hole which aligns axially with said cylinder, a sleeve slidably mounted in said hole and provided on the inside of said cylinder with a flange which is larger than said hole, a bolt slidably mounted on said sleeve and provided on the inside of said cylinder with a head, a first spring surrounding said bolt within said cylinder between said head and said sleeve and provided with an initial compression, a second spring surrounding said first spring between said head and said end plate and provided with an initial compression, a fixed angle bar provided with a slot which receives the lower end of said bolt, and two nuts screwed onto the lower end of said bolt and provided with confronting portions of reduced diameter which extend loosely into said slot in such manner that said bolt is free to move along said slot and that a limited amount of vertical movement of said bolt with respect to said slot is permitted, the parts being so proportioned that when said second lever is moved by said motor to the position in which the braking bar carried thereby occupies its braking position said springs will exert a force on said lever which is sufficient to overcome any rotational tendency of the lever and motor assembly due to gravity and that when said second lever occupies the position in which the braking bar carried thereby occupies its braking position and the piston of said fiuid pressure motor occupies its full projected position said first lever will be rotated to the position in which the braking bar carried thereby occupies its braking position.

HERBERT L. BONE. HAROLD C. CLAUSEN.

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