US2034286A

US2034286A - Fluid pressure brake

Info

Publication number: US2034286A
Application number: US471161A
Authority: US
Inventors: Clyde C Farmer
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1930-07-28
Filing date: 1930-07-28
Publication date: 1936-03-17
Anticipated expiration: 1953-03-17
Also published as: FR715138A; BE379218A

Description

M 1935- c. c. FARMER 2,034,286

FLUID PRESSURE BRAKE Filed July 28, 1930 2 Sheets-Sheet 1 4 63 2 CLYDEIQFARMER ATTORNEY.

March 17, 1936. Q Q R E 2,934,286

FLUID PRESSURE BRAKE Filed July 28, 1930 2 Sheets-Sheet 2 INVENTOR GLYD E C. FARME R A TTORNEY.

Patented Mar. 17, 1936 FLUID PRESSURE BRAKE Clyde 0. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application July 28, 1930, Serial No. 471,161

21 Claims.

This invention relates to fluid pressure brakes, and more particularly to an automatic fluid pressure brake system in which the brakes are applied by reducing the brake pipe pressure and are released when the brake pipe pressure is increased.

Particularly on long trains, there is danger of causing excessive and damaging shocks when the brakes are applied, due to the fact that the brakes are applied on the cars at the head end of the train, before they are applied on the cars at the rear end of the train, so that the slack is permitted to run in harshly and thus cause shocks.

One object of my invention is to provide means for delaying the brake application on the cars at the front end of the train, so that the brakes will apply at the head of the train more nearly in synchronism with the application of the brakes at the rear end of the train.

Another object of my invention is to provide means for preventing the retardation of the brake application on the front end of the train on trains running at high speed, since, in such cases, the slack will not run in so as to cause damaging shocks when the brakes are applied.

Another object of my invention is to provide means for preventing the retardation of the brake application on the cars at the front end of the train when the train is operating on a descending grade, after the brake cylinder pressure retainers become effective.

Another object of my invention is to provide means for retarding the rate of build up of brake cylinder pressure on cars at the head end of the train, in which the normal and retarded release positions of the K type of triple valve device are utilized to control the functioning of the means for retarding the rate of build up of brake cylinder pressure.

In the accompanying drawing; Figure 1 is a sectional view of a triple valve device embodying my invention, showing the triple valve in normal release position with the selector valve device in the position assumed on cars of the rear end of the train; Fig. 2 is a sectional View of the triple valve device, showing the parts in an inner position with respect to the normal release position with the selector valve device in the position assumed on cars at the front end of the train; Fig. 3 is a sectional view of the triple valve device, showing the parts in service application position with the selector valve device in the position assumed on cars at the front end of the train; and Fig. 4 a fragmentary sectional view of the triple valve device, showing the parts in service lap position.

The triple valve device may comprise a casing I having a piston chamber 2, connected by pas, sage 3 with the usual brake pipe 4, and containing a piston 5, and having a valve chamber 6 connected by passage 1 and pipe 8 to the usual auxiliary reservoir 9, and containing a main slide valve l0 and a graduating slide valve ll, having a movement relative to the main valve, and said valves being operable by piston 5, through a piston stem l2.

Slidably mounted in a bore of a cap l3, secured to the casing l at the rear end of the valve chamber 6 is a cylindrical member l4 having a stem 15 adapted to engage the end of the main slide valve l0 and subject to the pressure of a coil spring I6. The member I4 being adapted to yieldingly oppose movement of the slide valve H! from its normal release position to an inner position.

A device for controlling the retardation of flow of fluid to the brake cylinder in effecting an application of the brakes is provided, comprising a valve piston I'l, subject to the pressure of a coil spring which urges said valve piston to engagement with a seat rib l8. A stem [9 carried by the valve piston I'l extends through an opening 20 and is adapted to control the movement of a ball valve 2|. When the ball valve 2| is unseated by the stem l 9, a large flow capacity passage is open, through which fluid is supplied to the brake cylinder, but when the valve is seated, the flow to the brake cylinder is restricted.

A selector valve device for cutting said retarding means into and out of action is provided, comprising a pair of flexible diaphragms 22 and 23, having an intermediate chamber 24, containing a slide valve 25. Said valve is pressed to its seat by a spring-pressed roller 26 and is operated through a stem 27 which is interposed between the diaphragms.

A third flexible diaphragm 28 is also provided, which diaphragm is subject to the pressure of a spring 29 and is adapted to operate a stem 30, engaging the diaphragm 22.

For increasing the rate of flow to the brake cylinder after the brake cylinder pressure has been increased to a predetermined degree, a valve device is provided, comprising a flexible diaphragm 3|, having the chamber 32 at one side open to the atmosphere through a port 4| and subject to the pressure of a spring 33.

The diaphragm 3| is adapted to operate a valve 34, and said valve controls communication from a passage 35 having a restricted flow portion 36 to chamber'3l at one side of the diaphragm, said chamber being connected through a pipe 38 with the usual brake cylinder 39.

Assuming the triple valve parts in normal release position, as shown in Fig. 1, when the brake pipe is charged with fluid under pressure, fluid flows from the brake pipe to piston chamber 2 and thence to a passage 42, which registers in this position with a port 43 in the main slide valve l0. Said port is uncovered in this position by the position of the graduating valve I I, so that fluid under pressure is supplied to the valve chamber 6 and thence through passage I and. pipe 8 to the auxiliary reservoir 9.

The reservoir 6|, which may be an emergency reservoir, is charged from the valve chamber 6, through port 44 in the graduating valve ll, port 45 in themain slide valve l0, passage 46 and pipe 41. In releasing the brakes after efiecting an application of the brakes, the triple valve piston 5 may be moved eitherto the normal release position, as shown in Fig. 1, or to the inner position, as shown in Fig. 2, dependent upon the extent of the difierential of pressures between the brake pipe and the. auxiliary reservoir.

'At the head end ofthe train, where the rate and degree of increase in brake pipe pressure is greatest, the triple valve pistons move to the inner position, as shown in Fig. 2, the main slide valve In and the member l4 being forced rearwardly' against the resistance of spring I6.

When the triple valve parts move only to the normal release position in releasing the brakes, a passage 48, leading to chamber 49 at one side of the diaphragm 23, is connected to an atmospheric port 50, througha cavity 5| in the main slide valve Ill. Chamber 52, at the outer face of the diaphragm 22, is connected to the brake cylinder 39, through passage 53, cavity 54 in the main slide valve l0, and passage 55.

Although in releasing the brakes, cavity 56 connects passage 55 with exhaust passage 51, there will'be a temporary supply of fluid under pressure from the brake cylinder to the chamber 52, whichwill operate on diaphragm 22 to shift the slide valve 25 to the right, the diaphragm chamber 49 being at. atmospheric pressure. In this position. the passage 62 is connected, through a cavity 61 in the slide valve 25, with leading to valve chamber 69.

Valve chamber 69 V is open to passage 35, through which fluid under pressure is supplied to the brake cylinder, and with the valve piston I! in its upper seated position, the brake cylinder pressure in chamber 69 acts, through opening 20, on the inner seated area of the valve piston.- The fluid pressures on opposite sides of the valve piston beingbalanced, however, through the communication of the valve chamber 69 with the chamber 63, the spring 40 will hold the valve piston I! in its upper seated position, as shown in Fig. 1, regardless of the degree of brake cylinder pressure.

' Even after the pressure in the brake cylinder passage 68,

justment will only take place through variations in fluid pressure, when intended.

When the triple valve parts are moved to the inner position in releasing the brakes, as shown in Fig. 2, passage 48 is connected, through the passage 54 and cavity 56 with passage 55, so that initially, fluid under pressure from the brake cylinder is supplied to chamber 49. The chamber 52 is connected, through passage 53 and passage 10 in the slide valve In, with exhaust port 50, so that the brake cylinder pressure acting in chamber 49 against the diaphragm 23 will shift the diaphragm to the position shown in Fig. 2, in which slide valve 25 connects passage, 62 with chamber 24, which is open to the atmosphere, through an atmospheric port 64.

The chamber 63 is thus connected to the atmosphere, so that when the brake cylinder pressure is increased to a predetermined degree, the

brake cylinder pressure acting on the inner seated area of the valve piston, at the opening 20 will operate to shift the valve piston l1 downwardly against the resistance of spring 40.

In order to prevent the return movement of the triple valve parts from the inner position to the normal release position, after the parts have been shifted to the inner position in releasing the brakes, a resistance increasing cavity 15 is provided in the main slide valve l0. Said cavity is connected to a passage 16, which opens into a cavity '11 in the graduating slide valve l I when the valve II is moved to the right relatively to the main valve ID. A port 18 in the main valve, which also registers with cavity 11; is adapted to register with atmospheric exhaust port 50, only when the main slide valve Ill is shifted to its inner position.

As a consequence, when a main slide valve is shifted to its inner position, cavity 15 is vented to the atmosphere, so that the fluid pressure acting in valve chamber 6 on an area of the main valve corresponding with the area of the atmospheric cavity 15 creates a pressure to hold the main valve against movement from the inner position, through the pressure of spring [6. When, however, the brake pipe pressure is reduced to effect an application of the brakes, and the piston 5 moves the graduating valve toward the left, the port 16 is opened 'to the valve cham ber 6, so that fluid under pressure is then supplied to cavity 15, thus cutting the cavity out of action as a resistance increaser.

Before leaving a terminal, the brakes are always applied and then released in order to test the condition of the brakes, and thus when the brakes are released after the test, the triple valves at the head end of the train will move to the inner position, due to the high differential of pressures between the auxiliary reservoir and the brake pipe, while the triple valves at the rear of the train will only move to the normal release position.

As hereinbefore described, the selector slide valves 25 of the triple valves at the head end of the train, where the triple valves move to the inner position, will be shifted to the position in which passage 68 is closed by valve 25 and passage 62 is opened to the atmosphere, as shown in Fig. 2, while the selector slide valves 25 of the triple valves at the rear end of the train will be in the position in which cavity 61 connects

passages

62 and 58, as shown in Fig. 1.

When an application of the brakes is effected, by causing a reduction in brake pipe pressure in the usual manner, the triple valve piston 5 is moved to service position, in which, as. shown in. Fig- 3, port H in the main slide valve registers with passage 55 and port 44 in the graduating valve l l registers with port I I, so that fluid under pressure is supplied from the auxiliary reservoir to the brake cylinder by way of the passage 55 leading to chamber 31 and the restricted flow passage 12, the chamber 31 being connected, through pipe 38 with the brake cylinder 39. Fluid also flows from passage 55 through passage to valve chamber 69, and past the check valve 2| to passage 13, which provides a large flow passage to chamber 31 and the brake cylinder.

So long as the valve 2| is unseated as shown in Fig. l, a relatively rapid rate of flow to the brake cylinder is obtained. On cars at the head end of the train, the slide valve 25 is positioned so that passage 62 is connected to the atmosphere, with the result that on the front cars, as soon as the pressure of fluid supplied to the brake cylinder has been increased to a predetermined degree, preferably suflicient to cause the brake cylinder iston to move out and cause the brake shoes to engage the car wheels, the pressure acting on the exposed area of the valve piston H, at the opening 29, will be suflicient to cause the valve piston to be shifted downwardly, against the resistance of spring 45. As soon as the valve piston ll moves away from its upper seat, communication through an equalizing port 1:2 is closed, thus permitting the full area of the valve piston H to be subjected to the brake cylinder pressure. The prompt full movement of the valve piston to its lower position is thus assured.

In this position, the valve 2! is permitted to seat and thus cut off the further flow of fluid under pressure to the brake cylinder by way of the relatively large capacity passage. Fluid under pressure continues to be supplied to the brake cylinder by way of the restricted passage 12, until the pressure in chamber 3'! has been increased to a predetermined degree such that the pressure of spring 33 acting on diaphragm 3| will be overcome. The diaphragm 3! will then be deflected downwardly, opening the valve 34.

Fluid under pressure can now flow to chamber 3'! and the brake cylinder by way of the restricted passage 36. The object of the above described regulation of the rate of flow of fluid under pressure to the brake cylinder in effecting both service and emergency applications of the brakes is for the purpose of delaying the development of retarding force on the cars at the head end of the train, so as to provide time for the brakes to be applied at the rear of the train, and thus avoid heavy shocks, due to the running in of the slack.

It will be noted that on cars at the head end of the train, there is an initial inshot of fluid under pressure to the brake cylinder, just suflicient to ensure the outward movement of the brake cylinder piston, and then there is permitted a slow build up of brake cylinder pressure for a time suflicient to permit the brakes to be applied on cars at the rear of the train. After the brakes have been applied at the rear of the train, the valve 34 is operated, to permit a more rapid build up of brake cylinder pressure on the cars at the front end of the train.

On cars at the rear of the train, the slide valve 25 is set in the position in which passage 62 is connected to passage 63, with the result that when the brakes are applied, the pressure of fluid supplied to the brake cylinder is equalized on opposite sides of the valve piston ll, so that the spring 40 acts to hold the valve piston I! at its upper seat. As a result, onv cars at the rear of the train, the brake cylinder pressure can build up at a; relatively rapid rate, as permitted by the passage 13, which rate of flow continues, so long as the triple valve parts remain in service application position.

When the auxiliary reservoir pressure has been reduced by flow to the brake cylinder, in effecting an application of the brakes, to a degree slightly less than the reduced brake pipe pressure, the triple piston 5 is moved from brake application position to lap position, as shown in Fig. 4.

In this movement, the graduating valve II is shifted so that port 44 in the, graduating valve is moved out of registry with the port H in the main slide valve Hi. The further flow of fluid under pressure from the auxiliary reservoir to the brake cylinder is thus cut off.

The movement of the piston 5 and the graduating valve H to lap position operates only to out 01f the further flow of fluid under pressure from the auxiliary reservoir to the brake cylinder, and has no effect with respect to the selector valve device, the initial inshot controlling valve device, nor the valve device for controlling the final flow of fluid to the brake cylinder, the two last mentioned valve devices being controlled by brake cylinder pressure, as heretofore described.

When controlling a train after starting on a descending grade, it is not necessary or desirable to retard the rate of build up of brake cylinder pressure on cars at the front of the train and consequently means are provided for setting the selector valve device having the slide valve 25 to the position in which the inshot valve device is cut out of action.

For accomplishing the above purpose, the pressure of fluid retained in the brake cylinder by shifting the handle of the retaining valve device to the position for retaining fluid under pressure in the brake cylinder, is utilized to cause movement of the selector valve device to the cut out position.

The retaining valve device 59 is of the well known type having a handle fifl'adapted in one position to connect the pipe 58 directly to the at mcsphere, and adapted in another position to connect said pipe with the pressure retainer, so that a predetermined degree of pressure is retained in the brake cylinder.

As herefnbefore described, the movement of the triple valve parts to the inner position, causes the selector valve device to be shifted to the position in which slide valve 25 connects passage 62 with the atmosphere. the brakes is effected after a previous application, in which fluid is retained in the brake cylinder, as the main slide valve H! is moved over the normal release position in its movement to service application position, passage 53 is momentarily connected to the brake cylinder passage 55, through passage 54 and cavity 55. As a consequence, fluid under pressure is supplied to chamber 52, while passage 48, which is connected with cavity 54 in the inner position of slide valve IQ, is connected to the atmosphere, through cavity 5!. The chamber '35 is thus at atmospheric pressure when the slide valve iii passes over the normal release position, while chamber 52 is supplied with fluid at the pressure retained in the brake cylinder. As a result, the selector valve device is shifted to the right, so that the slide valve 25 is moved to connect the passage 62 with passage 88, and thereby out the inshot valve device out of action.

When an application of It will be apparent that in level grade operation, and also in the initial application of the brakes on entering a descending grade, the selector valve device will operate to permit the inshot valve device to function, while with all succeeding brake applications on a descending grade, the brake cylinder pressure held by the retaining valve device will automatically insure that the inshot valve device will be cut out of action. "In high speed service, it is not necessary to retard the application of the brakes on the head end of the train in order to avoid shocks, and in. order to cause the inshot valve device to be automatically cut out in high speed service, I rely upon the fact that in high speed service, a

higher brake pipe pressure (such as ninety pounds) is employed than in ordinary service,

where a standard brake pipe pressure of seventy pounds is employed.

When in low speed service with seventy pounds 7 29; so that the diaphragm 28 is then shifted to the right, causing the stem 30 to push the diaphragm 22 to the right, to the position in which slide valve 25 connects

passages

62 and 68, and thereby causes the inshot valve device to be cut out of action, regardless of its position in the train.

It will now be seen that the inshot valve device is automatically prevented from functioning in high speed service where a high brake pipe pressure is carried and also is prevented from functioning on descending grades after the first application of the brakes, where the retaining valve device is cut in to retain pressure in the brake cylinder.

There is now in general use on railroads, a triple valve device known as the K type, in which means for securing a retarded release of the brakes on the cars at the head end of the train is provided. In this type of triple valve device, the triple valve parts have a normal release position, in which the release of fluid from the brake cylinder is at a normal rate, and an inner position, in which the release of fluid from the brake cylinder is retarded. A yielding resistance device opposes the movement of the triple valve parts from the normal release position to the inner position.

The triple valve device shown in the drawings embodies the above described yielding resistance device of the K triple and utilizes the normal release and the inner retarded release positions of the triple valve parts to accomplish the desired functioning of my improvement.

It will now be evident that with my invention, the build up of brake cylinder pressure in making an application of the brakes is delayed on cars at the head end of the train, while on cars at the rear of the train, the build up of brake cylinder pressure is not delayed, so that the brakes at the head end of the train will not be applied with such force as to permit the slack to run in. When, however, thebrakes on the cars atthe rear have been applied with a certain force sufficient to prevent the slack from running in, the build up of brake cylinder pressure on cars at the front of the train is permitted to proceed more rapidly.

The conditioning of the apparatus to permit either a retarded or a rapid rate of flow to the brake cylinder is effected by means of a selector valve device, which in turn is positioned dependant upon whether the triple valve device has previously moved, in releasing the brakes to the inner release position, as would be the case on cars at the head end of the train, or to normal release position, as would be the case on cars at the rear end of the train.

For high speed service, means are provided for preventing the selector valve device from functioning to condition the apparatus for retarding the build up of brake cylinder pressure on cars at the head end of the train, by making use of the higher normal pressure carried in the brake pipe on trains in high speed service.

Means are also provided for preventing the apparatus from acting to retard the build up of brake cylinder pressure on cars at the head end of the train, when the train is operating on a descending grade with the brake cylinder pressure retainers set to retain pressure in the brake cylinder.

The subject matter relating to the controlled build-up of brake cylinder pressure in effecting a an application of the brakes is broadly claimed in my pending application, Serial No. 612,465, filed May 20, 1932.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a brake controlling valve device operative upon a reducfor delaying the build up of brake cylinder pressure, and means operative according to its position in a train upon movement of said brake controlling valve device to a predetermined position for conditioning said valve means so as to delay the build-up of brake cylinder pressure.

2. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a brake controlling valve device operative upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to efiect an application of the brakes, said valve device having a normal release position and movable upon a predetermined rate of increase in brake pipe pressure to an inner position, of valve means operative in eflecting an application of the brakes for delaying the build up of brake cylinder pressure, and means operative by fluid under pressure from the brake cylinder upon movement of said brake controlling valve device to said inner position for cutting said valve means into action.

3. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, a triple valve device operated upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder and movable'up'on an increase-in brake pipe pressure to a normal release position to effect the release of the brakes, and having an inner position, and a yielding resistance means for opposing movement of said triple valve device to its inner position, of valve means for retarding the rate of build up of brake cylinder pressure in effecting an application of the brakes, and means operated by fluid from the brake cylinder upon movement of said triple valve device to its inner position for cutting said valve means into operation, said valve means being cut out of operation upon movement of said triple valve device to its normal release position.

4. In a fluid pressure brake, the combination with a .brake pipe, brake cylinder, a triple valve device operated upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder and movable upon an increase in brake .pipe pressure to a normal release position to efiect the release of the brakes, and having an inner position, and a yielding resistance means for opposing movement of said triple valve device to its inner position, of valve means for retarding the rate of build up of brake cylinder pressure in effecting an application of the brakes, and means operated by fluid under pressure from the brake cylinder according to whether the triple valve device is shifted to its normal release or its inner position for cutting said valve means into and out device to its inner position, of valve means separate from said triple valve device for retarding the rate of build up of brake cylinder pressure in effecting an application of the brakes, and means controlled by fluid under pressure supplied from the brake cylinder according to the variations in pressure in the brake pipe from the head toward therear of the train for cutting said valve means into and out of operation.

6. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, auxiliary reservoir, a piston subject to the opposing pressures of the auxiliary reservoir and brake pipe, and valve means operated by said piston upon a-reduction in brake pipe pressure for supplying fluid to the brake cylinder, said piston and valve means being movable to one or the other of two positions, according to variations in the differential of pressures between the brake pipe and theauxiliary reservoir from the head toward the rear of the train, of means for retarding the rate of build up in brake cylinder pressure, and means operated by fluid from the brake cylinder for cut ting said retarding means into and out of action according to which of said positions, said piston is shifted.

'7. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a brake. controlling valve device operated upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder, of means for retarding the rate of flow of fluid under pressure to the brake cylinder, and means operated by fluid under pressure from the brake cylinder when the rateof increase in brake pipe pressure is relatively high to out said retarding means into action and when the rate of increase in brake pipe pressure is relatively low to out said retarding means out of action.

8. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a brake controlling valve device operated upon a reduction in brake pipe pressure for supplying fluid. under pressure to the brake cylinder, of means for retarding the rate of flow of fluid under pressure to the brake cylinder, mleans operated according to the rate of increase in brake pipe pressure for cutting said retarding means into or out of action, and means operated when the normal pressure carried in the brake pipe exceeds a predetermined degree for also cutting said retarding means out of action.

9. In a, fluid pressure brake, the combination with a brake pipe, brake cylinder, and a brake controlling valve device operated upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder, of means for retarding the rate of flow of fluid under pres,- sure to the brake cylinder, and means operated according to the rate of increase in brake pipe pressure for cutting said retarding means into and out of action, said cut-out means being also operated by fluid pressure retained in the brake cylinder to out said retarding means out of action.

10. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a triple valve device comprising valve means for controlling the supply and release of fluid under pres sure to and from the brake cylinden and a piston subject to variations in brake pipe pressnre for actuating said valve means, of means for retarding the rate of build up of brake cylinder pressure, a selector valve device havingone position for cutting said retardin means into action and another position for cutting saidretarding means out of actionsaid selector valve device beingoperated by fluid under pressure from the brake cylinder supplied by said triple valve device in operating to effect the release of thelbrakes.

11. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a triple valve device operated by variations in brake .pipe pressure for controlling the supply and release of fluid under pressure to and from the brake cylinder, of means for retarding the rate of .flow of fluid under pressure to the brake cylinder and a selector valve device operated by Variations in fluid pressure for cutting said retarding means into and out of action, said selector valve device being operated by fluid under pressure supplied to the brake cylindenand the supply of fluid underpressure for operating said selector valve device being controlled by said triple valvedevice When in a position for releasing the brakes.

12. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a triple valve device operated by variations in brake pipe pressure for controlling the supply and release of fluid under pressure to and from the brake cylinder, of means for retarding the rate of flow of fluid under pressure to the brake cylinder and a selectorvalve device operated by variations in fluid pressure for cutting said retarding means into and out of action, said selector valve device being moved to its cut-out position by fluid at brake cylinder pressuresupplied to oneside and being moved to its cut-in position by luid at brake cylinder pressure suppliedto theopposite sideof said selector valve device.

13. A triple valve device comprising a piston, a

main valve operated by said piston and having a normal release position and an inner position, yielding resistance means for opposing movement of said valve from the normal release position to-the inner position, and a resistance increasing cavity in said valve which is connected to the atmosphere in said inner position for causing said valve to resist movement from said inner position to the normal release position by action of said yielding resistance means.

14. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a triple valve device operated upon a reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder, of a valve device normally providing a relatively large area communication through which fluid under pressure is supplied to the brake cyliider in effecting an application of the brakes and operated upon a predetermined increase in brake cylinder pressure for cutting ofl? said communication, a restricted passage through which fluid flows to the brake cylinder in,the cut-ofi position of said Valve device, and an additional valve device subject on one side to atmospheric pressure and the pressure of a. spring and operated upon a further predetermined increase in brake cylinder pressure for opening an additional passage through which fluid under pressure is supplied to the brake cylinder.

15. In a fluid pressure brake, the combination with a brake pipe, brake cylinder, and a triple valve device comprising valve means for controlling the admission of fluid under pressure to and its exhaust from the brake cylinder, and a piston subject to brake pipe pressure for operating said valve means, said valve means having a normal release position and an inner position, of means for retarding the rate of build up of brake cylinder pressure and a selector valve device operated by variations in fluid pressure for cutting said retarding means into and out of action, said valve means being adapted in the normal release position to connect one side of said selector valve device to the brake cylinder and the opposite side to the atmosphere and adapted in its inner position to reverse said connections.

16. In an apparatus for effecting a service application of the brakes on the cars of a train, comprising brake cylinders, means for first making an initial inshot of fluid under pressure to the brake cylinderson cars at the front of the train and then restricting the rate of flow of fluid to said brake cylinders, and means for causing an initial and continuing high rate of flow, of fluid to the brake cylinders on cars at the" rear of the train. 1

17. In a fluid pressure brake equipment adapted to be normally charged with fluid to a certain pressure for one class of train service and adapted to be charged with fluid to a higher pressure for another class of train service, in combination, a brake pipe normally charged with fluid to the pressure normally carried in the equipment, a brake cylinder, a brake controlling valve device operated upon a reduction in brake pipe pressure to a brake applying position for supplying fluid under pressure to the brake cylinder, valve mechanism for retarding the rate of flow of fluid to the brake cylinder, and valve means operative whenever the brake equipment is normally charged with fluid to said higher pressure for cutting said valve mechanism out of action.

18. In a fluid pressure brake equipment adapted to be normally charged with fluid to a certain pressure for one class of train service and adapted to be charged with fluid. to a higher pressure for another class of train service, in combination, a brake pipe normally charged with fluid to the pressure normally carried in the equipment, a brake cylinder, a brake controlling valve device operated upon a reduction in brake pipe pressure to a brake applying position for v supplying fluid under pressure to the brake cylinder, valve mechanism for retarding the rate of flow of fluid to the brake cylinder, and valve means having a position for rendering said valve mechanism effective to retard the rate of flow of fluid to the brake cylinder and having a position-for rendering said valve mechanism ineffective to retard the rate of flow of fluid to the brake cylinder and being operative to the first mentioned position whenever the equipment is charged to said certain pressure and being operative to the second mentioned position whenever the equipment is charged to said higher pressure. r v

19. In a fluid pressure brake equipment adapted to be normally charged with fluid to a certain pressure for one class of train service and adapted to be charged with fluid to a higher pressure for another class of train service, in combination, a brake pipe normally charged with fluid to the pressure normally carried in the equipment, a brake cylinder, a brake controlling valve device operated upon a reduction in brake pipe pressure to a brake applying position for supplying fluid under pressure to the brake cylinder, valve means movable to one position in which said means is rendered effective to retard the rate of flow of fluid toithe brake cylinder and movable to another position in which said means is rendered ineifective to retard the rate of flow of fluid to the brake cylinder, and means operative whenever the equipment is charged with fluid to said higher-pressure for shifting J being rendered inoperative to vary the rate of flow of fluid under pressure to the brake cylinder when said other reservoir is charged to a pressure in excess of said certain pressure. l

21. In a fluid pressure brake, in combination, a brake cylinder, a reservoir normally charged with fluid from the brake pipe at a certain pressure, means operative to supply fluid under pressure from said reservoir to the brake cylinder to effect an application of the brakes, valve means operative to vary the rate of flow of fluid to the brake cylinder, valve means operative to'control the operation of said valve means, and means operative when said reservoir is charged to a'pressure in excess of said certain pressure for rendering said valve means inoperative to control the operation of said valve means.

CLYDE c. FARMER. j