US1796769A - Fluid-pressure braking apparatus - Google Patents

Description

March 17, 1931.

C. W. SPROULL FLUID PRESSURE BRAKING APPARATUS Filed April 22, 1929 Nm, n, Qm.

Patented Mar. 17, 1931 PATENT OFFICE t CLARENCE W. SPROULL, OF EDGILWOOD BOROUGH; PENNSYLVANIA, ASSIGNORTO THE UNION` SWTCH &,` SIGNAL COMPANY, Fy SWISSVALE, PENNSYLVANIA, A CORPO- FLUD-PI'LESSUEE BRAKING APPAIRAIIUS` Application filed April 22,

My invention relates to fluid pressure braking apparatus, and particularly'to,` automatic brake applying mechanism. More `particularly my invention relates to means for controlling the automatic application ot the brakes on a railway train.

IW-illdescribe one form of apparatus embodying my invention, and will then point out the novel Jeatures thereof in claims.

The accompanying drawing` is a diagrammatic vieta/.showing one form ot' fluid pres sure braking apparatus embodying my invention, the various valves being shown in section.

Referring to the drawing, the reference character R designates atrain carried relay which` is controlled in accordance with tratic conditions in advance of the train. Un-

-d'er normal conditions, With the trackway gized'.'` When relay` R is energized, a battery 2 supplies current to Winding 3 of a magnet` valve M, so that armature l of the magnet valve M is held downagainst the action of a spring 5' and the pressure in pipe 6, thus `holding stem 7 against valve seat 8 and U away from valve seat 9 so that a stop reservoir S is open to atmosphere through port 10';

The magnet valve M vserves to control the automatic application of the brakeson the train through an automatic application valveA. The brakes may also be applied manually by means of the enginemans brake valve B.

The application valve A comprises a valve body 11 divided into two chambers 12 and 13 by means ot a piston 14. The piston 14 is biased-to the right by a spring 16 and is arranged to operate a slide valve 15. Fluid pressure is normally supplied to the chamber 12 through pipes 17 and 18 from some convenient source, such as the main res-ervoir, not shown in the drawing. Piston 14 isvprovided With a leakport 19 which allows thepressure in chamber 132to build up to that'otthe main reservoir when pipe 6 con- 1929.. seran No. 357,007.

nected with this chamber is blanked by slide valve and by valve M, When the pressure is the same in both chambers 12 and 13 the piston is heldin its right-hand or release position by spring 1G.

The chamber 13 ofvalve A is connected to` the magnet valve Mby means of the pipe 6 which is normally charged to main reservoir pressure from chamber 13. Pipe 6 may also be connected with a pipe` 2O by means of a port 21 in the slide valve 15` under certain conditions which Will appear hereinafter.

The enginemans brake valve B comprises a valve seat 23, a rotatable member 24, and a valve chamber 25. The abutting surfaces of the valve seat and the rotatable member24 are provided with valve ports, certain of which may be brought'into registration by manipulation of the handle 26. When the valve B is in the running position, in which position it is illustrated in Fig. 1, fluid pressure is constantly supplied from the main reservoir to port 29 in member 24 through the feed valve 28 and pipe 27. Port 29 connects pipe 27 with the usual brake pipe 31 through pipe 30, and port in the slide valve 15. The brake pipe 31 is arranged to `initiate an application ot' the brakes on the` train when the pressure in the pipe is reduced. Main reservoir pressure is supplied to chamber 25 in valve B `through pipe 17.

The reference character V designates an equalizing valve comprising two chambers 32 and 33 separated by a movable piston 34. Associated with the. equalizing valve V and communicating With the chamber 33 of the valve V is an equalizing reservoir E. y The chamber 32 of valve V is constantly connected with the brake pipe 31, and the equalizing reservoir E and the chamber 33 of valve V are normally supplied with brake pipe pressure from the pipe 31 through port 35 otvalve A, pipe 30, port 29 in the enginemans brake valve B, pipe 36, port 370i valve A, and pipe 38. Under these conditions, the pressures on the tivo sides ot the piston 34 are equal, and the piston occupies its lower position, so that vent 61 is closed by plunger 10.

It slide valve 15 is moved toward the leit to its application position, the supply of brake the pipe 42 to escape into a cavity 45 in the' valve C at a slow rate when pipe 42 is connectedwith pipe 38. The cavity 45 is connected with a reduction limiting reservoir F by means of a pipe 46. rlhe pipe 41 communicates with a chamber 47 above the piston 49 of a regulating valve D. rEhe piston 49 is biased to an upper'position by means of a spring 50, and controls a plunger 54 shaped to lit in valve seat 51. When the. piston is in its upper position, so that the plunger 54 is out of engagement with the valve seat 51, communication is established between the chamber 47 on the upper side of the piston 49 and a chamber 56 on the lower side of the piston by means of a small port 52 passing through the plunger and the piston. The chamber 56 is connected with the cavity 45 of the valve C by means of the pipe 53, and is, therefore subjected to the pressure'of the reduction limiting reservoir F.

As shown in the drawing, relay R is energized so that magnet valve M is also energized. Stop reservoir S is therefore connected with atmosphere through port 10 of Vvalve M, and one end of pipe 6 is blanlred.

The application valve A occupies its normal position and the other end of pipe 6 is therefore also blanlred, so that pipe 6 and chamber 13 of valve A are charged to the main vreservoir pressure in chamber 12 of valve A.

The eneinemans brake valve B is illustrated l l t) l a ru 1n its running position.A lhe brake pipe 31 is therefore charged with fluid 'pressure to prevent a brake application, and the equalizing valve and the equalizing reservoir E are also charged with the same fluid pressure. Reservoir F is vented to atmosphere through pipe 46, cavity 45 of valve C, valve 44, chamber 48, pipe 42, cavityr2l of slide valve 15,

f pipe 20, and ports 60 and 59 of brake valve B. Chambers 47 and 56 of valve D are'both subjected to atmospheric pressure so that valve D is held open by the bias of spring 50.

inV explaining the operation of the apparatus, I will first assume that relay R becomes.-

de-energized, as by .a change from safe to unsafe traffic conditions. When this occurs winding 3 of valve M is cle-energized and stem 7 is pushed upwardly against seat 9 under the action of the spring 5 and the pressure in pipe 6. ReservoirS is then disconnected from atmosphere and is connected with pipe 6, and hence with chamber 13 of valve A. The pressure in chamber 13 therefore falls, and piston 14 is forced into its lefthand or application position by the main reservoir pressure in chamber 12. Slide valve y15, in moving to its left-hand or application position, disconnects pipe 20 from pipes 41 and 42, and connects pipe 20 with pipe 6. Pipe 2O normally communicates with atmosphere through a port'59 in the enginemans brake valve, which port is closed only when the valve B is in the lap position. 1When pipe 20 is disconnected from pipe 42, therefore, reservoir F, which communicates with pipe 42 through the check valve C, is disconnected from atmosphere, and when pipe 20 is connected with pipe 6, the stop reservoir S and the chamber 13 of valve A are vented to atmosphere. rlhe valve A, having once been moved to its application position, therefore remains in its application position even though relay R subsequently becomes energized so that valve M is again energized.

The sl'de ialve 15, in moving to its application position also disconnects pipe 38 from pipe 36 and connects pipe 38 with pipes 41 and 42. Vvlhen pipe 38 is disconnected from pipe 36, equalizing reservoir E and chamber 33 of equalizing valve V are disconnected from the brake pipe,and brake pipe pressure is therefore trapped in the equalizing reservoir and in chamber 33. When pipe 38 is connected with pipe 42 fluid pressure fro-m reservoir E flows through pipe 38, port 37 of valve 15, pipe 42, chamber 48 of valve C, restricted orifice 43, cavity 45, and pipe 46 into the reduction limiting reservoir F. The pressure in reservoir E therefore gradually decreases. Pipe 42 also communicates with chamber 47 of valve D through pipe 41, so that fluid pressure from reservoir E is also supplied to chamber 47. rihis pressure at first is sufficiently large so that the force exerted by this pressure on the upper side of the piston 49 is greater than the force exerted on the lower side of piston 49 by the spring 50 and the red uction limiting reservoir pressure in chamber 56, and piston 49 therefore moves downwardly and closes valve D immediately upon the operation of valve A. It will be apparent therefore that the reduction of the pressure in reservoir E at first takes place at a slow rate which for a given volumetric ratio of the reservoirs E and F is determined by the size of the orifice 43.

rlhe slide valve 15 in moving to its application position further disconnects the brake pipe 31 from pipe 30, by means of which the brake pipe is normally supplied with fluid pressure and the movement of the valve 15 therefore traps thethen existing brake pipe pressure in the brake pipe and in chamber 32 of the equalizing valve V. Since the pressure in reservoir E and chamber 33 of valve ever, piston 34 of valve Vis forced upwardly,

andthe brake pipe isthenyented to atmosphere through port 61 in such manner that the rate of pressure reduction inl the brake pipe Will notbe greater than the rate of pressure reduction in reservoir E.

It Will be apparentthat, as the pressure in reservoir lil decreases, the pressure in the reduction limiting reservoir F increases, and

. upper side oi' this piston, and valve l) therefore automatically opens. The opening of Valve D terminates what I snail call the li rst stage ot pressure reduction of the pressure in equalizing reservoir E, and provides a bypass around the Valve C so that fluid pressure from the equalizing reservoir E is now also supplied to the reservoir I? through pipe 38, port 37 of slide valve 15, pipe 41, chamber 4? of Valve D, port 52 of Valve D, valve 54-51, chamber 56, and pipes 53 and 46. F luid pressure 'from the reservoir E therefore now ilou's to the reservoir F at a more rapid rate than before valve D opened. The pressure in reservoir E will continueto decrease until the pressure in the reservoirs E and F is equal.

I will now assume that relay R again becomes energized as upon a change from unsafe to safe traffic conditions. Pipe 6 is therefore blanlred at valve 7, but the application valve remains in its application position because pipe 6 is still Vented to atmosphere through port 59 of the enginemans bralqe Valve B. Ii the engineman now Wishes to restore the application valve A to its release or normal position and thus release the brake, hemoves brake valve B to the lap position, in Which all pipes 17, 30, 27, 36 and 20, and also ports 57 and59 are blanked by the rotary member 24. Under these conditions, iluidV pressure, flowing from chamber 12 of valve A through leak port 19 into chamber 13 and pipes 6 and 20, builds up until the iluid pressures on both sides o' piston 14 are nearly enough equal to permit spring 16 to return Valve A to its normal position. Pipe 6 is then blanked by the slide valve 15, so that valve B may nonT be restored tothe running position in which it is illustrated in the drawing, and valve A will then remain in its normal position until relay R again becomes deenergized. Main reservoir pressure is then again supplied through feed valve 28, pipe 27, port 29 in valve B, pipe 30, and port 35 in Valve A to brake pipe 31 to recharge the brake pipe. Brake pipe pressure is then also supplied to equalizing reservoir E and chamber 33 of valve V in the manner hereinbefore described. Since pipe 42 is now connected with pipe 20, and since valve B is in the runningposition so that port GO open to atmosphere, the fluid pressure in the re duction limitingl reservoir F forces plug' 44 of check Valve C upwardly and vents the reduction limiting reservoir to atmosphere at a rapid rate so that the apparatus :is quickly restored to the normal condition.

I hare described in detail only that part oi' the apparatus Whichis involved in an automatic application of the brakes. It should be pointed out, however, that the enginemans brake Avalue may be operated as usual to control the brake pipe pressure manually through J[he medium of the eeualizing Valve V in accordance with standard practice.

In making an automatic application of the bralies it is desirable to lirst apply the bralres of the train lightly in, order to permit the ther between successive cars train slaclr to ufithout ence). .ve shocks or jolts, and then to increase the braking force a suilicient amount to bring the train to a stop in the desired distance. ln the practice ot my invention, this desirable result may be obtained by proportioningr the .folumetric ratio of the reservoirs lil and l? and the ports of the valves C and l) in such manner that the pressure in reservoir I@ during),` the first stage of the reduction, Will he reduced to a small extent at a comparatively slow rate, but that the pressure in reservoir E upon the termination o'll the first stage will be reduced to a considerable entent at a comparatively rapid rate.

It will thus be apparent that I have provided apparatus for automatically applyingr the brakes in which the brake pipe pressure upon an automatic application is dependent upon the erpializing` reservoir pressure which, in turn, is automatically reduced to a lirst predetermined extent at one rate which is preferably slow, and immediately thereafter to a second predetermined extent at a dilerentrate which is preferably fast.

Although .I have herein shown and described only one form ot'tluid pressure bralo ing apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing 'from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Jautomatic fluid pressure braking; apparatus, comprising' an eruuilizinp,` reservoir normally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, `and means for attimes automatically reducing the pressure in said reservoir to a predetermined eirtent at one rate and continuing said reduction at a different rate.

.illu

v 2. Automatic fluid pressure braking apparatus, comprising an equalizing reservoir normally charged withfluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, and means for at times automatically reduci g the pressure in said reservoir to a first predetermined extent at a slow rate, and immediately therafter to a second predetermined extentV at a more rapid rate.

3. Automatic fluid pressure braking apparatus, comprising an equalizing lreservoi r normallycharged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, means for at times causing an automatic uninterrupted reduction in the pressurein said reservoir, and means for automatically varying the rate of such reduction.

4. Automatic fluid pressure braking apparatus, comprising an equalizing reservoir Anormally charged with fluid pressure, brake controlling mechanism responsive to the pressure, in said reservoir, means for at times automatically and continuously reducing the pressure in said reservoir to a predetermined extent, and means for' automatically varying the rate of such reduction.

5. Automatic fluid pressure braking apparatus, comprising an equalizing reservoir normally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, a second reservoir normally connected with atmosphere, a valve containing a restricted passage, means including said valve for at times connectingV said equalizing reservoir with said second reservoir, and means responsive to the relative pressure in said two reservoirs for closing a ley-pass around said valve.

6.. Automatic fluid pressure b raking apparatus, comprising an equalizing reservoir nformally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, a reduction limiting reservoir, and means interposed between said equalizing reservoir and said reduction'limiting reservoir for at times automatically reducing the pressure in said equalizing reservoir to a first predetermined extent at one rate and immediately thereafter to a second predetermined extent ata different rate. 'Y

7. Automatic fluid pressure braking apparatus, comprising an equalizing reservoir normally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, a reduction limiting reservoir, and means interposed between said equalizing reservoir and said reduction limiting reservoir for at times automatically reducing the pressure in said equalizing reservoir to a first predetermined extent at a slow rate and-immediately thereafter to a second predetermined extent at a more rapid rate.

8. Automatic iiuid pressure braking apparatuscomprising an equalizing reservoir normally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, a second reservoir normally connected with atmosphere, a check valve containing a restricted passage, means including said check valve for at times connecting said equalizing reservoir with said second reser-v voir, a regulating valve comprising a plun er having a small port therein and operated y a reciprocable piston also having a small port which is a continuation of the port in said plunger, a spring for biasing said pistonto a position in which said valve is open, and a by-pass around said check valve including said regulating valve.

9. Automatic fluid pressure braking apparatus comprising an equalizing reservoir normally charged withfluid pressure, brake controlling mechanism responsive to the pressure in said reservoir, a second reservoir normally connected with atmosphere, a check valve comprising a cavity connected with said second reservoir and a chamber separated by a plug having a restricted orifice and movable by fluid pressure flowing from said cavity to said chamber to increase thev passage between said cavity and said chamber, means for at times connecting said equalizing reservoir with said chamber, la regulating valve comprising a first and a second chamber separated by a piston biased toward said first chamber and having a small port which is blanked when the piston moves against said bias, and means for connecting said first and second chambers of the regulating valve with the chamber and cavity of said check valve respectively for varying the rate of reduction of the pressure in said equalizing reservoir when the pressure in said equalizing reservoir has decreased to a predetermined extent.

lO. Automatic fluid pressure braking apparatus, comprising an equalizing reservoir normally charged with fluid pressure, brake controlling mechanism responsive to the pressure in said reservoir; a second reservoir normally connected with atmosphere, a valve containing a restricted passage means including said valve for at times connecting said equalizing reservoir with said second reservoir, and means responsive to the relative pressures vin said two reservoirs for opening a by-pass around said check valve when the pressure in said equalizing reservoirhas been reduced to a predetermined extent.

In testimony whereof I afhx my signature. CLARENCE W. SPROULL.

CTI

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