US807037A - Fluid-pressure brake. - Google Patents

Description

PATENTED DEC. l2, 1905.

W. P. A. MAGFAR-LANE.

FLUID PRESSURE BRAKE.

APPLIoATIoN FILED JULY 1s. 1905.

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WILLIAM P. A. MACFARLANE, OF CHICAGO, ILLINOIS, ASSIGNOR TO RICHARD FITZGERALD, OF CHICAGO, ILLINOIS.

FLUID-PRESSURE BRAKE..

Specification of Letters Patent.

Iatented Dec. 12, 1905.

Application lecl July 18, 1905. Serial No` 270,216.

To @ZZ whom/ if may concern.-

Beit known that I, WILLIAM P. A. MAG- FARLANE, a citizen of the United States, residingat Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Fluid-Pressure Brakes, of

i y service mechanism thereof, for the purpose of braking the car according to its empty and loaded weight, with the result that the car may be braked with an increased pressure-when loaded. lIn the present instance, and as hereinafter described, my invention is arranged t form a part of the so-called "triple-valve device and to be arranged in substantially the same caslng as the latter.

In the drawings, Figure 1 is a central sectional elevation of a triple-valve device embodying my invention; Fig. 2, asectional plan taken on the line 2 of Fig. 1 with a portion thereof broken away to expose parts beneath,

and Fig. 3 a detail illustrating the running of some of the ports and passages.

' In the present instance I have shown my invention applied to my form of triple valve I in which the brake-release mechanism, the

service mechanism, and the emergency mechanism are separate and independent both physically and operatively; but it will be understood that I do not limit my invention to any specific form or character of apparatus,

A plicable.

but contemplate using the same wherever ap- Inasmuch as the three mechanisms Just referred to do not constitute per se any part of my present invention, the same will' be described in a more or less general manner, but sufcient for a proper understandingof the construction and mode of operation of the new parts constituting my improvements or invention.

The triple-valve device herein shown comprises a main valve body or casing 1, having secured thereto in suitable manner the top cap 2, bottom cap 3, and supplemental casing 4, this structure having suitable connections with the train-pipe, auxiliary reservoir, and brakecylinder at the points, respectively, marked T P for train-pipe, A R for auxiliary reservoir, and B C for brake-cylinder.

Referring iirst to the emergencyvalve mechanism, which is contained within the' supplemental casing 4, such casing has an end cap 5, which closes the outer 4end of a chamber in which the emergency-valve piston 6 travels. Upon the outer end of the rod GfL of this piston is arranged the emergency-valve 7, which is in the form of a puppet-valveadapted to seatupon the seat 8 and to thereby normally close the port 9 through such seat. The piston-rodpasses through a partition 10, but does not [it tightly therein, thereby providing a leakage or restricted feed from the train-pipe in to that part marked 11 of the piston-chamber formed on the right-hand side, Fig. l, of the emergency-piston, that partof the piston-chamber on the other side of the piston being for convenience indicated by the reference character 12. The trainpipe air passes from the train-pipe through the connection marked T P and through the passage marked 13 in the supplemental casing, past the emergency-valve and feeds freely and without obstruction to the chamber 12 through the large passage 14n near the upper end of such supplemental casing. If desired, a light spring 15 may be employed on the outer side of the emergency-piston to assist in seating the emergency-valve after an emergency action. Upon the train-pipe reduction suitable for emergency action the pressure in the Achamber l2 is suddenly reduced; but the pressure in chamber l1, not being able to leak back into the'train-pipe suiciently fast, expands in such latter chamber, thereby forcing the emergency-piston outwardly and lifting the emergency-valve oif its seat, so thatthe train-pipe pressure is vented from the trainpipe directly to the brake-cylinder through the rather large and direct passage 16, eX- tending transversely of the valve-body. The reservoir-pressure is also admitted in emergency action on top of the train-pipe air thus vented to the brake-cylinder in a `manner hereinafter explained. This direct and transverse passage 16 is provided with a check- Valve 17, normally held to its seat 'by the coiled spring 18.

The brake-release mechanism and the service mechanism are each operated and under the control of separate and independent diaphragme 19 and 20, respectively, which are clamped to the valve-body by the caps 2 and 3, respectively, the diaphragm 19 being clamped directly by its cap and the diaphragmY IOO 2O indirectly'in the manner hereinafter eX- plained.

Referring first to the brake-release mechan- Ism, the brake-release valve (marked 21) is ar ranged to operate. i n a chamber 22 in the valvebody and to govern a brale-releaselport123, leading to the atmosphere, such passage being formed adjacent to the release-valve in a seat or block 24, as clearly indicated in Fig. 1. The release-valve is arranged to'govern the release of pressure from the brake-cylinder through the transverse passage 16 and lpassage 25, connecting between the transverse passage, chamber 22, and release port or passage 23. Thetrain-pipe air is fed to the auxiliary reservoir and to the brake-release' mechanism first through a common passagel and thence by separate lpassages 33 and 34, leading, respectively, to the auxiliary reservoirand to the under side-of the diaphragm 19. The passage 33 continues as a passage 35 through the top cap 2, past a check-Valve44,

`and through a restricted port 46, thence through passages 37 and 38 to the auxiliary reservoir. A short passage 39 leads from passage 37 to the upper side of the diaphragm 19, so that the-latter is always exposed on its upper face to reservoir-air and on its lower face to train-pipe air.

Referring next to the service-valve meehanism as herein shown, the diaphragm 20 carries a service-valve 48, arranged to Work in a chamber 49, vinterposed between the port and a passage 5T, leading from the reser- Voir through the valve-body to the chamber on the upper side of the diaphragm 20. The port 50 communicates with the brake-cylind er through the connecting-passage 52 and the 'direct transverse passage 16. If desired, a

the-brakes the reservoir-pressure will forcethe diaphragm 20 downward, and therebyopen the service-valve, and thereby permitting the auxiliary-reservoir pressure to flow from the.

passage 57 through the chamber 49 and Vports and passages 50 and 51 and 16 to the brakecylinder. e

The triple valve as so far described is the same as heretofore madeby me, and it is in connection with such triple valve, and particularly with the service mechanism thereof, that my invention in its present embodiment is arranged to cooperate. My invention comprises means for preventing under certain conditions the admlsslon of excess pressure finto the brake-cylinder, or apressure in excessof'apredetermined amount, so that the `wheels of the car cannot be slid by any excess pressure admittedto the brake-cylinder when the car is empty, and such means as herein shown arefalso arranged to permit .the full pressure to be admitted into the brake-cylinder when-the car is loaded. Furthermore,

such means which are arranged to be manuallyset to a loaded-car-position are adapted tobe automatically returned to empty-car position whenever'ethe car kis 'set out from the train and is no'longer in communication with `the airdrumon alocomotiv'e.

-brake-cylinderthe service-,valve is held closed,

and 'thereby preventedY from-fadmittingany more'pressure to the brake-cylinder, notwithstanding furtherrreductions offtrain-pipe pressure, and I also 'provide an a-rrangement for rendering suchl means inoperative 'at the will ofthe operato1,|sothatthe full pressure may be utilized for loaded-car braking.

As herein shown, I interpose -between the bottom face of the main valve-body 1 and the bottom cap 3 a substantially cylindrical casing 60, which by preference serves to directly clamp the diaphragm 2O of thefserviee mechanism in place. rlhis casing 60 is provided with a chamber 60,in which is arranged a movable abutment,- in-'the present vinstance a diaphragm 61, which is clamped-'to such-casing directly by the bottom capi3. This dia- -phragm 61 carries a central stem or plunger 62,` which projects upwardly through a stuing-box 63 to a position in `proximity to the diaphragm 2O of the servicemechanism. -N ormally,-ho\vever, this plunger is positioned at such a distance from the `latter diaphragm as to permit the same to operate freelygand to thereb5T ad mit reservoir-pressure to the brakecylinder withoutany interference; but thearrangement is such that upon an excess of -pressure in the brake-cylinder the plunger is moved upwardlyA and againstthe diaphragm 20, or rather against the nut 64, which holds the service-valve to its diaphragm. The result of this interposition of the plunger 62.

into the path of movement ofthe diaphragm 2O is to prevent the operation of theservice mechanismand to keepl the service-valve upon its seat regardless of furthertrain-pipereductlons. To cause excess pressure m the brakecylinder to operate the extra diaphragm 61 and -move it upwardly in the manner just explained, the lower face thereof is exposed to brake-cylinder pressure-through the passage IOO IIO

65, leading `from the transverse passage'l downwardly through the valve-'body Il, and through the bottom cap 43 to the under side of the diaphragm' 61, as clearly indicated in Fig. l, it being understood, as hereinafter explained,ithat the interior of the casing 60- that is, the chamber 60 on the upper side of 'the diaphragm 61--is normally at atmospheric pressure. The diaphragm161 is loaded or normally pressed downwardly to theposition shown in Fig. l by means of a spring 66 abutting at its lower end preferably upon' a circularsaddle 67, resting directly upon the diaphragm 6l tov prevent wear thereof, and at its upper end against an adjusting-ring or -spring-seat 68, which is screw-threaded upon that portion of the casing 60 which form's'the stung-box. This spring represents or corresponds to the predetermined pressure which is to be admitted to the brake-cylinder for braking an empty car, and'it serves to resist that pressure from the brake-cylinder which,

when the brakes are applied, is pressing uppredetermined pressure admitted to the brakecylinder, can be varied according to the direction of adjustment of the ring.

In order to adapt the car for loaded-car braking, which fis herein accomplished by throwing this'special mechanism out-of action, I provide a transverse bore or passage through the casing 60 at one side thereof and counterbore such passage in order to providealarger chamber 69 and a smaller chamber 70, the remainder 7 lof such passage being of sucient diameter to freely receive a rod or plunger 72, as clearly indicated in Fig. 2. The outer end of the chamber 69 iis arranged to communicate with the auxiliary reservoir through the usual passage 57, leading to the upper side of the diaphragm 2O of the service mechanism, and through a branch passage 73, leading from the passage 57, which passage 73 extends from the valve-body through the casing 60 and throughaportion of the small cap 60b and then upwardly through aseat 74, arranged in the bottom ofthe chamber 69, where it emerges or terminates as a port 75. Auxiliary-reservoir pressure is therefore always present in the passage 73 and at the port 75; butthe ow of such pressure to the chamber 69 is prevented by the valve 76, which is carried-on the inner end of the rod or plunger 72. This plunger is spring-pressed toward the valve-seat by means of a spring 77, situated in the chamber 70, which forms the spring case or barrel therefor. The chamber 69 is normally exposed `to atmosphericpres sure,\.inasmuch as the tit of the plunger 72 in the passage 71 is not a tight one, and likewise the chamber above the diaphragm 6l is normally exposed to atmospheric pressure, inasmuch as the chamber (designated 6021 for convenience) is exposed to atmospheric pressure, because the same is connected with the chamber 69 by means of a cross-passage 78, as indicated in Fig. 2. The outer end of the rod or plunger 72 which extends extraneous of the casing 60 is arranged to be drawn outwardly manually when it is desired to adjust the apparatus for loaded-car braking, as hereinafter described, and to this end such plun-v ger has a pin-and-slot connection with a lever 79,V pivoted intermediate its length on a fulcrum 8O on the lug or extension 81, proceeding from the casing 60, as indicated in Fig. 2. In vthe present instance the'pin-andslot connection is obtained through the medium of a pin 82 on the rod 72 and aslot 83 in' the lever 79. This lever is provided at its opposite ends with eyes 84 and 85, which are similar, with the exception thatthey point in opposite directions, thel eye 84 being connected with a rod 86,extending transversely of the car to near one side thereofys'o that it may be Within easy reach of the trainman, and the other eye is connected with asimilar rod 87, extending to the other side of the car. By these means an outward pull of either of these special rods moves the plunger 7 2 in the same direction-that is, outwardly.

Normally the device is positioned for emptycar braking, the improvements constituting my invention being in operative condition and ready to move and hold the service-valve upon its seat when the brake-cylinder pressure exceeds a predetermined amount. I/Vhen, however, it is desired to set Vthe apparatus for loaded-car braking, the trainman pulls one ofthe rods 86 87, with the result that the plunger 72 is drawn outwardly against the tension'of the spring 7 7 and the circular bead or ring 88 on the upper surface of the body of the valve 76 caused to seat upon the gasket 89, arranged at one end of the chamber 69. The result of this movement of the plunger 72 is to open the auxiliary-reservoir port and passage and to close the passage or communication to the atmosphere through the passage 7l. The reservoir-pressure now flows through the chamber 69, around the valve 7 6, through passage 78, and into the chamber 60, with the result that the pressure of the spring 66 upon its diaphragm 6l is augmented by the auxiliary-reservoir pressure, and such diaphragm is therefore prevented from being moved upwardly by the brake-cylinder pressure, although such latter pressurev may be in excess of the load or amount represented by the spring 66-that is, the predetermined degree of pressure. The diaphragm 61 and its IOC' plunger 62 are vtherefore rendered inoperative and thrownfoutofvactiong so that they are incapable of any interference Withtheoperation of the service mechanism,-with the resulty thatI the full amount of reservoir-air that can be obtained on an equalization can be admitted to the lbrake-cylinder irrespcctivefof the predetermined degree of pressure to which the apparatus' has been set for emptyfcar braking.' As iswell known, the pressure of the brakey system does not remainvery long o'n` alcar Which nas been set out from a live train-that is, ay train connected up with a locomotive or source of compessed airor in a ca-r in atrain which has been detached from the locomotive-inasmuch as the air soon leaks away. Byzreason of rthis fact the return of my apparatus from its manually-set position for loaded-car brakingto the-empty-car position is automa-tic in' character, for, aswill be understood from an inspection of Fig. 2, the valve 76 after being set for loaded-car 'braking is held to such set orshit'ted position by thereservoir-air against tension of the spring 77. When, however, such air has leaked oil from the car or been reduced below the degree of pressure .exerted by the spring 77, the valve 7 6 will be seated by the spring and thev chamberv EL thereupon exhausted to atmosphere through the passage 71.

It will be understood thatvvhen the-devicev is normal-that is, in condition for empty-car braking-emergency action maybe obtained Without inteference from the special arrangement above described, inasmuch asvupon a sudden and considerable reduction of trainpipe pressure necessary for emergency action the train-pipe air Will be vented to the brakecylinder, and such pressure so admitted will be augmented by thereservoir-pressure, which is admitted by the opening of the servicevalve. Inasmuch as the pressure in the trainpipe has been practically or considerably depleted or reduced, the pressure on the lower side of the diaphragm20 has been correspondingly reduced, so that the considerable preponderance of the pressure as equalized in emergency action will prevent the plunger 42 from affecting the operation of the servicevalve, so that full equalization between the reservoir and brake-cylinder can be obtained in emergency action. Y

By preference my improvements form a component part ot' the triple-valve device, and the same are compactly arranged in respect thereto; but it Will .be understood that the particular location and arrangement thereof are not essential and that I am not to be limited thereto exceptwhen the claims expressly require it, inasmuch as I contemplate using my invention Wherever applicable regardless of particular environments and position.

I claim- 1. In a device for actuating Huid-pressure brakes, the combination with the service-valve mechanism actuated l byy variationsin f trainpipe pressureg'of means for closing the servicevalve and actingto so close the valveonly when the brake-'cylinder pressure exceeds'a predetermined maximum amount.

2.l Inl a device forl actuating fluid-pressure brakes,the combinatiomWith'the'service-valve mechanism actuated byv variations in trainpipe pressure, ofy fluid pressure actuated means for closings-theservice-valvc-and acting to so close the valve-onlyfwhen the brake-cylinderfpressure exceeds aprcdetermin ed maximum` ramount. r y

3. Inaldevicer-forf actuating fluid-pressure bra-kes, the'combi'natiomwith the service-valve mechanismactuatedv by. variations-in tra-inpipe pressure', of means under-the con-trol of thebrake-cylinder pressure for closingthe service-valveand actin-g v-to so closev the-valve only when'thebrake-cylinder vpressure exceeds aV predetermined 4maximum amount.-

4; In adeviceffor actuating fluid-pressure brak-es, the combination with the-service-'valve mechanism actuated by variations-in trainpipel pressure, ,of l-u'idpressureactuated mechanism under the control of the brakecylinder pressure `and arrangedto hold-the service-valvc-'closed when the brake-cylinder pressure exceeds a predetermined -maximum amount.

5. In a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism,- of ay movable abutment under the controll of `the brake-cylinder pressure and inactive during ordinary-graduating action of the service-valve mechanism, said abutment having-a projection arranged, When the abutment is operated by excess brake-cylinder pressure, to cooperate with the service-valve andv holdthe same closed when the brake-cylinder pressure exceeds a predetermined maximum amount.

6. In a device for actuating fluid-'pressure brakes,the combination, with the service-valve mechanism, of a movable abutment under the control of the brake-cylinder pressure, and a stem or plunger actuated by the abutment and arranged to be projected into the path of movement of the service-valve and, when operated by excess brake-cylinder pressure, to hold such valve closed.

7. In a device for actuating fluid-pressure brakes,the combination, with the service-valve mechanism actuated by variations in trainpipe pressure, lof a movable abutmentnormally exposed on one side to atmospheric pressure and on the other .side to brake-cylinder pressure when the brakes are applied, and means operated by such abutment for controlling the action of the service-valve and arranged to close the latter onlywhen the brake-cylinder pressure exceeds a predetermined maximum amount.

8. vIn a device for actuating Huid-pressure brakes, the combination, with the service-valve IOO Iov

mechanism actuatedvby variations in trainpipe pressure, of a movable abutment normally exposed on one side to atmospheric pressure and on the other side to brake-cylinder pressure when the brakes are applied, said abutment being normally held With a yielding pressure corresponding with thc predetermined pressure to be permitted in the brake-cylinder, and means operated by such abutment Jfor controlling the action of the service-valve and arranged to close the latter lwhen the brake-cylinder pressure exceeds a predetermined amount. j

9. In a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism, of a movable abutment normally exposed on one side to atmospheric pressure and on the other side to brake-cylinder pressure when the brakes are applied, a spring cooperating With the abutment and opposing the brake-cylinder pressure with a tension corresponding with the predetermined degree of pressure desired in the brake-cylinder, and

vmeans operated by such abutment for controlling the action of the service-valve and arranged to close the latter when the brakecylinder pressure lexceeds a predetermined amount. i 10. In a device for actuating luid-pressure brakes, the combination, with the service-val ve mechanism, of a movable abutment normally exposed on one side to atmospheric pressure and on the other side to brake-cylinder pressure when the brakes are applied, a spring cooperating With the abutment and opposing the brake-cylinder pressure with a tension corresponding With'the predetermined degree of pressure desired in the brake-cylinder, means for adjusting the tension of said spring,- and means operatedby such abutment for controlling the action of the service-valve and arranged to close the latter when the brakecylinderpressure exceeds a -predetermined amount.

11. ln a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism, of a movable abutment normally exposed on one side to atmospheric pressure and on the other side to brake-cylinder pressure when the brakes are applied, a spring cooperating with the abutment and opposing the brake-cylinder pressure with a tension corresponding with the predetermined degree of pressure desired in the brake-cylinder, an adjustable spring-seat by Whose adjustment the tension of the spring is regulated, and means operated by such abutment for controlling the action of the service-valve andl arranged to close the latter when the brakecylinder pressure exceeds a` predetermined amount.

12. In a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism, of a diaphragm controlled by brake-cylinder pressure and normally subject to a pressure eq ualing a predetermined brakecylinder pressure, and a stem carried thereby and arranged to be projected to interfere With and'close the service-valve when the brakecylinder pressure exceeds such predetermined amount.

13. In a device Jfor actuating fluid-pressure brakes, the combination, with the service-valve I mechanism, of a diaphragm controlled by brake-cylinder pressure, a spring opposing the brake-cylinder pressure, and a stem carried by the diaphragm and arranged to be projected to interfere with and close the service-valve when the` brake-cylinder pressure exceeds the predetermined vamount represented by said spring.

111. In a device for actuating Huid-pressure brakes, the combination, with the service-valve mechanism, of a diaphragmv controlled by brake-cylinder pressure, a spring opposing the brake-cylinder pressure, an adjustable seat for said spring to vary the tension thereof, and a stem carried by the diaphragm and arranged to be projected to interfere withV and close the service-valve when the brake-cylinder pressure exceeds the predetermined amount. A

15. In a device for actuating fluid-pressure bra'kes,the combination, With the service-valve mechanism, of a diaphragm controlled by brake-cylinder pressure, a spring opposing the brake-cylinder pressure, an adjustable seat for said spring to vary the tension thereof, a spring-seat on the diaphragm to receive the spring, and a stem carried by the diaphragm and arranged to be projected to interfere with and close the service-valve when' the brakecylinder pressure exceeds the predetermined amount.l

16. In a device for actuating Huid-pressure brakes, the combination, with the service-valve mechanism, of a diaphragm controlled by brake-cylinder pressure, a spring opposing the brake-cylinder pressure, a stem carried by the diaphragm and arranged to be projected to interfere With and close the service-valve when the brake-cylinder pressure exceeds the IOO predetermined amount, and a stuHing-box for l IIS pressure brakes in which the service-valve mechanism is independent ot' the brake-release and emergency mechanisms, Huid-pressure-operated mechanism under the control of the brake-cylinder pressure for holding the service-valve closed when the brake-cylinder pressure exceeds a predetermined amount.

1Q. In a valve device Jfor actuating iuidpressure brakes, in which the service-valve mechanism is independent of the brake-release and emergency mechanisms, mechanism under the control of the brake-cylinder pressure for holding the service-valve closed when the brake-cylinder pressure exceeds a predetermined amount, said last-named mechanism being arranged to resist the brake-cylinder pressure, and means for varying the degree of such resistance.

20. In adevice for actuating Huid-pressure brakes, the combination, with theservice-valve mechanism, of mechanism under the control of brake-cylinder pressure for holding the service-valve closed when the brake-cylinder pressure exceeds a predetermined amount, and means for rendering said last-named mechanism inoperative at the will of the operator.

2l. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of mechanism under the control of brake-cylinder pressure for holding the service-valve closed when the brake-cylinder exceeds a predetermined amount, and manually-operated means for rendering said lastnamed mechanism inoperative.

22. In a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism, of mechanism under the control of brake-cylinder pressure for holding the service-valve closed when the brake'- cylinder exceeds a predetermined amount, comprising a movable abutment having a stem arranged to be projected into the path of movement of the service-valve, said abutment being exposed on one side to brake-cylinder pressure and on the other side to atmospheric pressure for empty-car braking, and means for admitting pressure to that side of the abutment thus exposed to atmospheric pressure for loaded-car braking.l

23. In a device for actuating fluid-pressure brakes, the combination, with the service-valve mechanism, of mechanism under the control of brake-cylinder pressure for holding the service v alve closed when the brake cylinder pressure exceeds a predetermined amount, comprising a movable abutment having a stem arranged to be projected into the path of movement of the service-valve, said abutment being exposed on one side to brake-cylinder pressure and on the other side to atmospheric pressure for empty -car braking, and means for admitting auxiliary-reservoir pressure to that side of the abutment thus exposed to atmospheric pressure for loaded-car braking.

24. In a device for actuating'iuid-pressure brakes, the combination, with the service-valveU mechanism, of mechanism under the control of brake-cylinder pressure for holding the service-valve closed when the brake-cylinder exceeds a predetermined amount, comprising' a' movable abutment having a stem arranged to be projected into the path of movement of the service-valve, said abutment` being exposed on one side to brake-cylinder pressure and on the other side to atmospheric pressure for empty-car braking, and meansV under the control ofv the operator for closing the communication between said abutment and the atmosphere and simultaneously admitting auxiliary-reservoir pressure to the abutment to oppose the brake-cylinder pressure.

25. In a device for actuating Huid-pressure brakes, the combination, with the service-valve mechanism, of mechanism under the control of brake-cylinder pressure for holding the service valve closed when the bra-kecylinder exceeds a predetermined amount, comprising a movable abutment having -a 4stem arranged to be projectedinto'the path of movement or the service-valve, said abutmenty being exposed on one side to brakecylinder pressure and on the other side to atmospheric pressure for empty-car braking, and means Jfor closingthe communicationbetween said abutment and the atmosphere and simultaneously admitting auxiliary-reservoir pressure to the abutment to oppose the brake-cylinder pressure, said means comprising a valve controlling the flow of said;auxiliary-reservoir pressure, and a stem connected with said 'valve Jforoperating it.

26. In a device for actuating Huid-pressure brakes, the combinatoruwith the service-valve mechanism, of mechanism under the control oi" brake-cylinder pressure for' holding the service-valve closed when the brake-cylinder exceeds a predetermined amount, cornprisinga movable abutment having a stem arranged to be projected into the path of movement of the service-valve, said abutment being exposed on one sidetobrake-cylinder pressure and -on the other side to atmospheric pressure for empty-car v braking, andmeans for closing the communication between said abutment and the atmosphere'andsimultaneously admittingv auxiliary-reservoir vpressure to the abutment to oppose the brake-cylinder pressure, said means comprising a springpressed valve controlling the iow of said auxiliary-reser-voir pressure, and astem having manually-operated means for actuating the same.

27. In a device for actuating fluid-pressure brakes,the combination, with the service-valve mechanism, of mechanism under the'control of brake-cylinder pressure for holding the service Valve closed, when the'V brakecylinder exceeds a predetermined amount, comprising a movable abutment having a stem arranged to beV projected 'intothe patlr of movement of the service-valve, saidl abutment being exposed'on one side to lbrake-cylinder pressure and on` the other side lto atmospher'icpressure for empty-car braking, .said

IOO

IIO

abutment operating in a ,chamber and constantly'exp'osedto brake-cylinder pressure on one side and on the other side normally exposed to atmospheric air, a valve-chamber arranged at one side of and communicating with the abutment-chamber and normally at prising a movable abutment having a stem arranged to be projected into'the path of movement of the service-valve, said abutment being exposed on one side to brake-cylinder pressure and on the other side -to atmospheric pressure for empty-car braking, said abutment operating in a chamber and constantly exposed to brake-cylinder pressure on one side and on the other side normally exposed to atmospheric air, a valve-chamber arranged at one side of and communicating With the abutmentchamber and normally at exhaust, a spring-pressed valve in the valve-chamber for closing said exhaust and atthe same time opening the chamber to auxiliary-reservoir air which is. thereby admitted to the abutmentchamber to oppose the brake-cylinder pressure.

29. In adevice for actuating iiuid-pressure brakes, the combination, with the service-valve mechanism, of mechanism under the control ot' brake-cylinder pressure for holding the service-valve closed when the brake-cylinder exceeds a predetermined amount, comprising a movable abutment having a stem arranged to be projected into the path of movement of the service-valve, said abutment being exposed on one side to brake-cylinder pressure and on the other side to atmospheric pressure for empty-car braking,said abutment operating in a chamber and constantly exposed to brake-cylinder pressure on one side and on the other side normally exposed to atmospheric air, a valve-chamber arranged at one side of and communicating With the abutment-chamber and normally at exhaust, a valve in thevalve-chamber for closing said exhaust and at the same time opening the 'chamber to auxiliary-reservoir air Which is service, brake-release and emergency mechanisms, and means also arranged Within said casingv for closing communication betweeny the auxiliary reservoiry and brake-cylinder and normally inactive but arranged to act when the brake-cylinder pressure has reached apredetermined amount, regardless of the pressure in the auxiliary reservoir.

31. In a device for braking cars according to Weight empty and loaded, the combination, With the triple-valve and the service-valve mechanisms thereof, of means arranged to close the service-valve when, in empty-car braking, the brake-cylinder pressure reaches a predetermined amount, and mechanism for rendering said means inoperative.

32. The combination of a casing containing service, brake-release and emergency ymechanisms, the service mechanism being independent of the other mechanisms, and means also arranged in the casing for controlling the operation of the service mechanism and arranged to hold the same to a position preventing the flow of auxiliary-reservoir pressure to the brake-cylinder when the brake-cylinder pressure exceeds a predetermined amount.

' 33. In a device for actuating fluid-pressure brakes of the species in which the service, brake-release and emergency mechanisms are independent, physically and operatively, the combination, with the service mechanism, of means for rendering 'the same inoperative when -the brake-cylinder pressure exceeds a predetermined amount.

34. In a valve device for actuating fluidpressure brakes in which the service-valve is independent of the brake-release and emergency valves, means for closing the servicevalve when the brake-cylinder pressure exceeds a predetermined amount.

35. In a valve device for actuating fluidpressure brakes in Which the service-valve 1s independent of the brake-release and emergency valves, controlling means for closing the service-valve when the brake-cylinder pressure exceeds a predetermined amount, and means for rendering said controlling. means inoperative.

36. In a valve device for actuating fluidpressure brakes in which the service-valve is independent of the brake-release and emergency valves, controlling means for closing the service-valve when the brake-cylinder pressure exceeds a predetermined amount, said controlling means being normally in operative condition, and means for rendering such controlling means inoperative at the will of the operator.

37. In a device for actuating Huid-pressure brakes, the combination, With the servicevalve, of mechanism arranged to hold the service-valve closed when the brake-cylinder pressure exceeds a predetermined amount,

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and means for rendering saidlast-named mechl when the brake-cylinder pressure reaches or anism inoperative at the will of the operator. lexceeds a predetermined maximum amount.

38. In a device for actuatingv fluid-pressure brakes, the combination, with the service- 5 valve mechanism, of means inactive during. Witnesses:

graduation operations of the service-valve S. E. HIBBEN, but arranged to act to close the service-valve LOUIS B. AERWIN.

WILLIAM P'. A. MACFARLANE.

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