US1122253A - Air-brake system. - Google Patents

Description

H. D. CARROLL. AIR BRAKE SYSTEM.

APPLIGATIQN FILED FE11M. 1914.

Patented Dec. 29, 1914.

2 SHEETS-SHEET 1.

WITNESSES H. D. CARROLL.

AIR BRAKE SYSTEM.

APPLIGATION rlLnn Pmm` 1914,

Patented Dec. 29, 1914.

2 SHEETS-SHEET 2. W 29 V/ WITNESSES M Mmmm/s.

THE MORRIS PETERS Co 4 PHn'lo-L/THO. WASHINUTUN. Dv c HARRY D. CARROLL, OF NORRISTOWN, PENNSYLVANIA.

AIR-BRAKE SYSTEM.

Specification of Letters Patent.

Patented Dec. 29, 1914.

Application filed iFebruary 4, 1914. Serial No. 816,465.

T0 all whom it may concern.'

Be it known that l, HARRY D. CARROLL, a citizen of the United States, residing at Norristown, in the county of Montgomery, State of Pennsylvania, have invented a new and useful Air-Brake System, of which the following is a specification.

My invention consists of improved valve mechanism for railway air-brakes, in which the triple-valve controlling the air for the brake-cylinder will be rendered certain in its operation by improved means for locking and unlocking the graduating stem.

It further consists of mechanism by which the auxiliary reservoir and brake cylinder can be automatically emptied of pressure by triple valve and locomotive brake valve Inanipulation.

1t further consists of such mechanism embodied with the triple valve controlling the air from the brake-cylinder which will be cert in in its operation and will not be liable to stick and trap air in the brake-cylinder and thereby hold the brake set on the car.

lt further consists of other novel features of construction, all as will be hereinafter fully set forth.

r1`he annexed drawings and the following description set forth in detail one mechanical form embodying the invention, such detail construction being but one of various mechanical forms in which the principle of the invention may be used.

1n said annexed drawings Figure 1 represents a sectional view of the main oper ating parts of my improved air-brake mechanism. Figs. 2, 3, 4, 5 and 6 represent sectional detail views of the several positions of the triple valve in operation.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings, the reference numeral 1 indicates the valve-casing inclosing the several elements embodying my invention. Said casing has at its bottom an inlet, 2, to which the train-pipe is connected, and at its top a neck, 3, which is secured in the auxiliary reservoir, 4, of the car. A passage, 5, leads upward from the bottom of the valve-casing into a casing, 6, secured to the valve-casing by bolts, 7, and said casing has a wall, 8, formed with a series of openings, 9, leading into a chamber, 10, having a par tition, 11, forming one wall of the same and formed with a central opening, 12, in which the forward end, 13, of a graduating stem 67 is loosely slidable, and a series of openings, 14, surrounding such central opening. At the other side of the partition 11, the valve-casing is formed with a cylinder, 15, in which slides a piston, 16, secured upon the end of a valve-stem, 17, of a triple-valve, said piston having a boss, 1S, upon one face which can bear against a seat, 19, at the end of the cylinder and has a notch, 20, to admit of passage of air when the boss is seated. rlhe cylinder has a longitudinal groove 21, at one end, of greater length than the thickness of the piston, so that air may pass through said groove and around the piston when the latter is moved against the end of the cylinder or when the piston-stem 1'( is moved against the retarding stem 53 which tends to hold the piston 16 olf from its seat 19. The cylinder communicates with a triplevalve chamber, 22, the opposite end of which communicates with the neck 3 entering the auxiliary reservoir through a passage 23. The triple-valve is composed of a main valve, 24, slidable upon the bottom of the valve-chamber and forced against the same by a spring, 25, and adapted to be engaged by two annular flanges, 26 and 27, upon the valve-stem, and a small valve, 28, slidable upon the upper side of the main valve and fitted into a'recess, 29, in the valve-stem and having a spring, 30, forcing it against its seat upon the main valve.

An emergency-cylinder, 31, is formed be neath the triple-valve chamber, and has an enlargement, 32, having a port, 33, communicating with the brake-cylinder, which is not illustrated, as it forms no part of the present invention. Below the enlargement, a downwardly facing seat, 34, is secured, from which extends an upwardly extending spider-frame, 35, in which a neck, 36, of an emergency piston, 37, having a loose fit in the cylinder, is guided. A valve, 38, has its upper face seated against said seat 34, and has an upwardly projecting stem, 39, entering the neck and into the emergency piston. A chamber, 40, is formed below the valveseat and has a valve-seat, 41, opening into a chamber, 42, into which the inlet 2 for the train pipe opens, and a check-valve, 43, is

seated upon said valve-seat, and a stem, 44, projecting downward from the valve 38 is slidable in an axial bore, 45, in said checkvalve and is forced upward by a spring, 46, in said bore. A cylindrical piston-chamber, 47, is formed at the side of the emergency valve cylinders and chambers and has its lower end communicating with the trainpipe chamber 42, and said piston-chamber communicates at its upper end with an intermediate chamber, 48, of smaller diameter, which has a port, 49, opening to the atmosphere, and said latter chamber has its upper end communicating with a piston-chamber, 50, of larger diameter. A small diameter piston, 51, tits to slide in the small diameter piston-chamber, and a large diameter piston, 52, fits to slide in the large diameter pistonchamber, and said pistons are connected .oy a rod, 53, to which is secured a slide-valve, 54, which has play over the exhaust-port 49 and will uncover the same when the pistons are in their uppermost positions. The upper end of the upper piston-chamber has a restricted port, 55, through which it communicates with a chamber, 56, communicating through a restricted port, 57, with the triplevalve chamber. A retarding stem, 58, is slidable in the neck 3 which communicates with the auxiliary reservoir of the car, and has a spring, 59, coiled around it and servingl to force it inward against the triplevalve stem and hold the piston ofi from its seat until the tension of the spring 59 is overcome.

The casing 6 has a cylinder, 60, within it, preferably formed in one piece with the wall 8, and having an opening, 61, in its upper head. Two pistons, 62 and 63, are slidable in said cylinder and are connected by a locking-rod, 64, formed with a notch, 65, which will register with the inner end of a slot, 66, the rear end, 67, of the forked graduating rod straddling such locking rod. The graduating rod is in alinement with a boss, 68, upon the piston of the triple-valve, and has a spring, 69, forcing it toward said boss and piston. The cylinder in which the pistons slide is formed with two recesses and 71 which are wider at their upper portions than at their lower portions, being V-shaped in the form herein shown, and said recesses are longer than the thickness of the lower piston, so that a by-pass may be produced through either of said recesses around the piston, whenever the piston is moved over the recess. The lower piston has a port, 72, through it. The partitions 11, secured between the valve-casing 1 and the casing 6 has gaskets, 73, secured by the bolts 7 between the meeting faces of said casings and the partition, and the meeting portions of said casings have cored or otherwise formed a ZiZ-zag or otherwise forwardly and backwardly bent passage, 74,

passing through the partition and gaskets, and communicating with the lower end oi the cylinder 60 through a passage, 75, in the wall 8. Said passage communicates with a similar Zig-zag or otherwise forwardly and backwardly bent passage, 76, in the meeting edges of the lower portion, 77, and the upper portion, 78, of the valvecasing 1, said portions being secured together by bolts, 79, having nuts, 80, and

having a gasket, 81, between them.

A casing, 82, has a dome, 83, which is connected to the tripple-valve chamber by a pipe, 84, and is formed with a cylinder, 85, separated from the dome by a partition, 86, having openings, 87, and with a cylinder, 88, separated from the former cylinder by a partition, 89, and said former cylinder has an outlet, 90, to the atmosphere. rl`he lower end of the lower cylinder communicates with a smaller diameter cylinder, 91, the lower yend o1 which communicates with a chamber, 92, communicating with an annular chamber, 93, surrounding the small.- diameter cylinder. A passage, 94, extends from the dome to the upper end of the smalldiameter cylinder. A passage, 95, extends from the lower end of the upper cylinder to near the upper end of the snrall-diameter cylinder with which it comn'ninicates through a port, 96. A passage, 97 forms communication between the upper end oi the second cylinder and near the lower end of the small-diameter cylinder. A passage, 98, extends from the lower end of the second cylinder to a chamber, 99, having a valveseat, 100, upon which an upwardly opening check-valve, 101, is seated and opening into the annular chamber 93. A passage, 102, extends from the lower end of said chamber to the chamber 92 in the bottom of the casing. A piston, 103, is fitted to slide in the upper cylinder, and is secured to a pistonrod, 104, to which a piston, 105, is secured,

slidable in the second cylinder, and a smaller diameter piston, 106, is secured to the lower end of said piston-rod and is slidable in the small-diameter cylinder. A slide-valve, 107, is connected to the piston.- rod to slide over the port, 96, and has a spring, 108, keeping it to its seat. A plunger, 109, is slidable in the center of the partition, 86, and has a stem, 110, guided in a recessed plug, 111, in the center of the dome and forced downward by a spring, 112.

rllhe main valve 24, of the triple-valve slides upon the bottom of the triple-valve casing and can be shifted by the annular iianges upon the valve-stem striking its ends, and the small valve 28 slides upon the top of said main-ifalve. The small valve has a recess, 113, which has play over two ports, 114 and 115, in the main valve, which ports have play over ports, 116 and 117, in

the seat of the valve-chamber and respectively communicating through passages, 118 and 119, with the upper end of the emergency piston chamber and the chamber 40 below the emergency valve 43. A passage, 120, extends from the enlargement 32, communicating with the brake-cylinder, and has a port, 121, opening into the triplevalve chamber.. An exhaust port, 122, in said chamber leads to the atmosphere, and is located between said port 121 and the port 116, and the main valve is formed with a recess, 123, which spans and can connect said port 121 with said exhaust-port 122. Said recess has a bridge-piece, 124, slidable over the exhaust-port and capable of partly covering the same under certain conditions to be hereinafter described. The main valve has two ports, 125 and 126, through it, which can be brought to register' with the port 121. A port, 127 is formedin the seat for the main valve of the triple-valve, and forms communication through a passage, 128, to the chamber, 48, and the main valve of the triple-valve has a recess, 129, having play over said port and opening through such main valve by a port, 130. An emergency port and passage, 131, extends from the seat for the main valve of the triplevalve to the upper end of the emergency cylinder. f

When one or more cars having the brake mechanism is coupled to a locomotive and the train pipe is connected to the valves and air pressure is started, 'such pressure passes through the valve casing up through the casing 6, and the openings in the wall 8, andv thence through the openings 14, in the partition 11, into cylinder 15, and if the pressure is suflicient, it will force triple piston 16 and stem 17 against retarding stem 58, compressing spring 59 until piston 16, and boss 18, seat againstseat 19, moving slide valves 24 and 28, as in Fig. 2. The said pressure in cylinder 15 will now pass over the top edge of the piston 16, through the by-pass 21, and the said air pressure is restricted in its flow by passing the air through slot 20, of piston 16, into the triple valve chamber 22, and thence to the auxiliary reservoir, through the passage 23, 'and the neck 3. Said pressure also charges chamber 50 on top of piston 52, through the ports and chamber 57, 56 and 55, seating the said piston as shown in Fig. 1, and it also charges pipe 84 of casing 82, as will be hereinafter fully set forth. At the same time the said pressure enters the open upper end of the cylinder 60, through opening 61 and also enters said cylinder past the loosely fitting graduation stem 67, into chamber between piston 62 and 63, and thence through the passage 72, in the lower piston 63, into the lower end of said cylinder, whence the said pressure passes through port 75, and thence it passes around the zig-zag passages 71 and 7 6 in the joints of the casings. The pistons 62 and 63, and locking bolt or piston rod 64 are normally held in lower position by gravity. The pressure also charges the chamber 40 from the chamber 42, by raising check valve 43, and compressing spring 46, and the said pressure charges also pass to lower piston 51 and force the said piston upward, if there has been a reduction of pressure upon the top of piston 52, as will be hereinafter' fully set forth. As the said pressure has forced 'triple piston 16, and moved slide valve 28 and slide valve 24 to the position shown at Fig. 2, and if there has been a period of application of pressure to make the brake cylinder as shown at Figs. 4 and 5, or 6, which will be hereinafter fully set forth, the brake cylinder pressure is slowly released as shown at Fig. 2, through exhaust 122, from opening 33, through port 121, and recess 123, said exhaust 122 being restricted by small bridgepiece 124, partly covering recess 123, pressure being thus slowly released while vthe auxiliary reservoir is slowly charged in this position of the triple valves. The valves and pistons 'are in the extreme left position and compressing the retarding spring 59.

In an air-brake system, comprising a train of cars and a locomotive having an airpump and a train-pipe connected to such pump and to triple-valves in the brake mechanisms of the several cars, it is evident that a change of pressure in the train-pipe will become active in the mechanisms near the pump more quickly than in the mechanisms farther from the same. The slow pressure in a device at a distance from the compressor will act against the piston to force the latter and the valve into the position illustrated in Fig. 3, connecting the airpressure from the brake cylinder to freely pass through the port 33, passage 120, valverecess 123, and exhaust 122, while air passes over the piston 16, through the groove 21, and toward the reservoir and other parts of the apparatus.

Release of a measurably graduated air pressure in the train pipe by the locomotive brake valve will also allow a measurable air pressure to go to the brake cylinder from the auxiliary reservoir to set the brakes on a car as shown at Figs. 4 and 5, said pressure being reduced slowly and gradually in the train pipe, such pressure releasing through nozzle 2 and from casing 6 and the openings in the wall 8, and thence from theopenings 14 and from cylinder 15, air pressure in the auxiliary reservoir will now move the triple piston 16 and valves 28 and 24- into position shown in Fig. 4, wherein the small valve 28 uncovers the port 126, which is partly connected with the passage 120 and thus admits air pressure from the-auxv iso iliary reservoir t0 the brake cylinder, at the same time the recess 113 in valve 28 connects ports 114 and 115, said ports connecting ports 116 and 117, as shown in Fig. 4. Pressure from chamber 40 on top of trainpipe check-valve 43 now charges said passages, pressure at chamber' 42 now raises said valve 43, compressing spring 46, and

ypasses to said chamber and passage 119,

through said ports and recesses into chamber 36 of piston 3T and opening 38, and brake cylinder setting brakes on car with a determined and measured force. The triple valve having caused a further train pipe reduction of pressure as shown at Fig. 4, and said pressure reduction in train pipe from said chamber 42, up through passage 119, will cause the triple valve piston in each of a series of brake devices in a train of cars to be serially actuated to cause a reduction of pressure in' each of said devices. The said triple valve will now automatically go to triple valve position, Fig. 5, by auxiliary reservoir forcing triple piston against graduation stem 12, compressing spring 69, forcing said stem against piston rod 64. Triple piston 16 now being in position, Fig. 5, has moved slide valves 24 and 28 farther to the right, blanking port 117, and stopping the flow of pressure from said train pipe through port 115, and fully connecting port 126 with port 121, air pressure in auxiliary reservoir now passes to brake cylinder in a larger volume' through the fully connected ports 126 and 121 until pressure in auxiliary reservoir is reduced to slightly less than the pressure on brake pipe side of triple piston 16, now brake pipe pressure will force triple piston, and the added resistance of slide 24 to position shown at Fig. 1. To move the triple piston 16 and slide valves 24 and 28, from position Fig. 1 to release brake cylinder pressure, and to further charge auxiliary, it will be again necessary to further increase brake pipe pressure on brake pipe side of triple piston 16, moving the said triple piston to positions shown as Fig. 2 or 3.

Under certain conditions the triple piston 16 will not respond to the increasing train pipe air pressure as the triple valve may be gummed up and sticking which will prevent the brake pipe pressure from actuating said piston, or the piston packing ring may be worn and thus .allow the brake pipe pressure to pass over edge of piston 16 and to equalize with auxiliary reservoir pressure without moving vthe piston to the desired position, as shown in Fig. 2 or 3. Such defects will trap pressure in brake cylinder and hold brake set. The said defect is automatically prevented by my device, when pistons 51 and 52, with piston rod 53, and slide valve 54 are positioned as shown in Fig.v 1. The trple'piston 16 being now in position,

as shown in Fig. 1, 4, or 5, the pressure has been reduced above the piston 52, and in this position the recess 129 in the valve 24 registers with port 127 and allows pressure from the auxiliary reservoir to charge into chamber 48, between the pistons 51 and 52. The train pipe pressure will not move triple piston 16 to its normal position Fig. 2 or 3 if the piston is for some reason stopped, but will leak by said piston. The auxiliary reservoir pressure is prevented from charging chamber 50 on top of large diameter piston 52, by reason of the restricting ports 55 and 57 and the chamber 56 restricting the flow of air pressure from the auxiliary reservoir. The brake pipe pressure at chamber 42 will actuate piston 51 and move the same upwardly, exposing chamber 48 to atmosphere through exhaust 49, and allowing the auxiliary reservoir pressure to vent to the atn'iosphere through the passage 128. This will overcome the said defects and trainline pressure will now move the triple piston 16 to the normal position, Fig. 2 or 3. Main valve 24 now blanks passage 128, stopping the iiow of pressure from the auxiliary reservoir by way of the exhaust port 49, and the pressure from the auxiliary reservoir will charge chamber 50 on top of piston 52, by ports 55 and 57 and chamber 56, and will actuate piston 52 with the attached valve mechanism closing exhaust 49. 1t becomes necessary to empty the auxiliary reservoir of all air pressure, when the car with mechanism attached is detached from locomotive, as otherwise the brake pipe leaking to atmosphere will cause the pressure in the auxiliary to set the brakes. In my device, this is performed automatically by triple valve and locomotive brake valve manipulation, which acts by means of the device shown as connected into the triple valve chamber by pipe 84. Normally the pressure passes from the auxiliary reservoir through the pipe 84 into the dome top of cylinder 82, and bears against the upper face of piston 103, forcing the piston down closing the port 96 in the intermediate cylinder 88, also port 97 in the small diameter cylinder, said air also passes down through the passage 94 into intermediate cylinder 88, and bears against the lower face of piston 105 and the upper face of the small diameter piston 106, and passes through the passage 98, to chamber 99, whence it forces the check valve 100 up against stop, and charges the chamber' 92 and the lower part of small diameter cylinder until air pressure is normal and the same as auxiliary reservoir air pressure in chambers 92 and 93, when the pressure above check valve 100 will seat said valve against seat 101. -Pressure being reduced in auxiliary reservoir also reduces pressure from chamber 99 of casing 82, through passage 98, intermediate chamber 88, passage 94, and from dome top of cylinder through pipe 84, to auxiliary reservoir. Pressure is trapped in chambers 92 and 93 by check valve 100, and also in the lower end of the small piston cylinder 91 and. if the pressure above the piston 103 is reduced to suoli extent as it is desired the pressure from below will act against said piston 106, forcing the same upward, and the three pistons raise the slide valve 107, and move it upward oidl of port 96, when the air from the auxiliary reservoir passing throughthe pipe 84:, dome 83, passage 94:, cylinder S8, out through port 96, passage 95, into the lower portion of the upper piston cylinder, will assist in holding said piston up, whence the air fully escapes to the atmosphere through the exhaust 90. At this time, pressure being reduced in auxiliary reservoir, and if there is any pressure in brake cylinder, and if auxiliary pressure is reduced below brake cylinderpressure, the latter pressure will force triple valve 2a off its seat, and escape to atmosphere by exhaust port 122. Air pressure in chambers 92 and 93 which has acted against piston 106 and forced the latter upward, exposing the port and passage 97, passes into the cham ber 88 above the intermediate piston 105 by the passage 97, acting, together with the weight of the piston and the tension of the spring 109 to force the pistons downward to close the port 96 by the slide-valve 107. rllhe pressure in brake cylinder and auxiliary reservoir will thus be fully released so that it cannot act against the triple piston and more the said piston into position and apply the brake on the car.

My invention also consists of an improved means for locking the graduating stem 67 upon a gradual brake pipe reduction of pressure, and if the triple valve has any defects, my improved device holds the triple piston and valve in the desired position,

that has been herein described and shown as Fig. 5, preventing the triple valve from going at this time to an undesired position shown in Fig. 6, and if it is desired to move triple valve to position, as shown in Fig. 6, which will be hereinafter fully set forth, the graduating stem 67 that is in alinement with triple piston boss 68, will be automatically unlocked by air pressure in a pressure chamber in said device. In

triple valve positions Fig. 4 or 5, this sure at the brake pipe side of piston 62, and piston 16, and with the said measured gradual brake pipe reduction at the face of the brake pipe side of piston 62 through the port 72 and recesses 70 and 71, pressure passes out of lower chamber of casing 60,

.through passage 72, into chamber on the upper side of piston 63 and out to train pipe past the loosely fitting graduating stem 67. 1f the said train pipe reduction is a heavy gradual reduction that moves triple valve to position shown Fig. 5, it causes such reduction of pressure in chamber above piston 62, that has a large opening 61 into casing 6, and the pressure in pressure chamber in the'lower side of piston 63, will force the said piston upward. The pressure in said chamber expands as the said pressure forces piston- 63 upward, and if the two pistons 62 and 63 are not yet balanced, the pressure in chamber on the lower side of piston 63, will force the said piston to recess 70, or the higher recess 71 which is farther up in the wall of casing 60, and pressure in said chamber will be reduced more rapidly and, as the recesses which assist passage 72 to reduce the said pressure, are wider at the upper portion than the lower portions, being il-shaped in the form herein shown (at F ig. 1) and said recesses are longer than the thickness of the lower pistons, they allow a` by-pass, when the pressure in the lower chamber under piston 63 forces the said piston to the said recesses. rlfhe said pressure will reduce rst slowly, then in larger volume as the piston 63 travels farther up and by suoli increase prevents pressure in the chamber under the lower piston 63, from unlocking graduating stem 67, on a gradual train pipe reduction that allows auxiliary reservoir pressure to move the triple valve to the positions, as shown at Figs. l and 5.

1f the joints in the valve casing become leaky by the nuts on the fastening bolts loosening or the gaskets being defective, the air-pressure within the casing is reduced and the air pressure beneath the lower piston 63 would be liable to overcome the downward pressure upon the pistons and force the pistons upward to bring the notch of the piston rod to register with the end of the graduating stein 67 and thus allow the piston 16 and valve to move into emergency position.V As, however, the inclosed space below the piston 63 is connected by the passages 75, 71 and 76, and leakage from said space will equal leakage from` the space in the casing through the same leak in the joint, the relative pressures in opposite directions upon the piston structure will remain the same, and no movement of the pistons and locking rod will take place.

If the said gasket 73 or 81 n are defective or said nuts 7 or 8O should be triple valve from going to an undesired position, in the case of such brake pipe reductions.

In case the air pressure is quickly released in the train pipe in an emergency,

the triple valve piston being forced over by the auxiliary reservoir pressure to the extreme right as shown at Fig. 6, and as vthe said pressure quickly releases out of the opening 61 from top of piston 62,A air pressure under lower piston 63 will quickly force said piston 63 upward to the full travel of said piston 63 allowing notch 65 of said piston rod 64, to be in alinement with the graduating stem 67, and as the triple piston boss 68 forces graduating stem 67, and compresses the spring 69, it forces said stem 12 into said notch 65 of said piston rod 64, until said triple piston is stopped by wall 11. Auxiliary pressure now flows down through port 131 on the top of emergency piston 37, and the said piston forces valve 38 down compressing spring 46 in bore of check valve 43, forcing said valve 38 oif of seat 34. Pressure at chamber 42 now forces check valve 43 upwardly further compressing spring 46. Air pressure at nozzle 2, chamber 42 now flows to brake cylinder by check valve 43 to chamber 40, past seat 34, to chamber 32, to opening 33. Pressure in brake cylinder now reaches and seats check valve 43 against seat 41, and the spring 46 expands and seats valve 38 against seat 34, and as main valve is in position as shown at Fig. 6, and port 125 in triple valve 24 registers with port 120, the auxiliary pressure flows to brake cylinder by passages 131 and 121 and with the additional brake pipe pressure applies the brake on a car quicker and with greater force than can be applied at triple position Fig. 4 or 5.

Gther modes of applying the principle of my invention may be employed, for the mode herein explained. Change may therefore be made as regards the mechanism thus disclosed provided the principles of construction set forth respectively in the following claims are employed.

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

1. In an air brake system, a triple-valve chamber having communication with the train-pipe air-supply, a cylinder transverse to said triple-valve chamber and having one open end, a triple-valve in said triple-valve chamber and having a central boss upon its piston, a graduating stem transversely slidable in the transverse cylinder and in alinement with the boss of the triple-valve piston and adapted to be engaged by the saine and formed with a forked end, a spring bearing against said graduating stem to force it toward the boss of the triplevalve piston, a piston slidable in the upper open end of the transverse cylinder, a piston slidable in the closed lower end of said transverse piston and formed with a port through it, and a locking stein connecting said pistons and formed with a notch at its lower end into which the crotch of the forked end of the graduating stem may engage, said triple-valve piston and upper piston in the transverse cylinder being actuated by the train-pipe air pressure.

2. In an air brake system, a casing adapted to communicate with the train-pipe air pressure, a triple-valve having a piston, a graduating stem provided with means for forcing it toward the piston, a locking stem transverse to and adapted to engage said graduating stem and formed with a notch, and means controlled by the train-pipe airpressure for longitudinally moving said locking stem to engage or disengage said graduating stem in or from the notch.

3. In an air brake system, a casing comprising portions having their meeting faces secured together, a gasket interposed between said meeting faces and a zigzag passage formed in the meeting portions of the casing portions and in communication with the air supply.

4. In an air brake system, a triple-valve chamber having communication with the train-pipe air-supply, a cylinder transverse to said triple-valve chamber and having one open end, a triple-valve in said triple-valve chamber and having a central boss upon its piston, a graduating stem transversely slidable in a central opening in the transverse cylinder and in alinement with the boss of the triple-valve piston and adapted to be engaged by the same and formed with a forked end, a spring bearing against said graduating stem to force it toward the boss of the triple-valve piston, a piston slidable in the upper open end of the transverse cylinder, a piston slidable in the closed lower end of said transverse piston and formed with a port through it, the said cylinder having two or more V-shape recesses in the wall of said cylinder, said piston in the inclosed end of said cylinder may be moved by air pressure in the inclosed end of said cylinder to register with said recesses, and a locking stem connecting said pistons and formed with a notch at its lower end into which the crotch of the forked end of the graduating stem may engage, said triplevalve piston and upper pist-on in the transverse cylinder being actuated by the trainpipe air pressure.

5. In an air brake system a easing comcommunicaton with the closed end of said prlslng portions havlng thelr meetlng faces cylmder. secured together, a. cylmder havlng a. closed L HARRY D. CARROLL. end, a plston structure 1n Saud cylmder, a

gasket .interposed between said meeting faces Ttnessesz and it zigzag passage formed n the meet- WILMAM LAWLER,

ing portions of the easing portions and in E. L. ANDREWS.

Copies of this patent may be obtained for ve cents each, sy addressing the Commissioner of Patents,

. Washington, D. C.

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