US901923A - Air-brake. - Google Patents

Description

J. E'. MGELROY.

AIR BRAKE.

APPLICATION FILED MAR.2,1907.

Patented 0G11. 20, 1908.

AUXILIARY RESERVOIR r Witnesses M@ UNITED STATES PATENT OFFICE.

JAMES F. MCELROY, OF ALBANY, NEW YORK, ASSIGNOR TOv CONSOLIDATED CAR HEATING COMPANY. A CORPORATION OF WEST VIRGINIA.

AIR-BRAKE.

'Specification of LettersPatent.

Paienteaooc. 2.o, 190s.

Application tiled` March 2, 1907'. Serial No. 360,281.

have invented certain new and useful Im proveniente in Air-Brakes; and in the following specification and accompanying drawings I have described and illustrated that form ofmy invention which I now consider as the best out of the various forms in which its principles may be embodied.

ln the drawings Figure l is a side elevation of my triple valve; Fig. 2 is avertical, axial section taken at rightv angles to the View in Fig. l. f

My invention relates to air brakes and consists of certain improvements applicable particularly to air brakes of the typeshown in my Patent- No. 7 68,537 dated August 23, 1904.

AMore specifically, I have devised a new arrangement of the valve which, in loakes of my type, serves to supply the auxiliary reser- Voir from the trainline, and to admit trainline air to the brake cylinder in advance of` the admission thereto ot'air from the auxiliary reservoir, in the event of a sudden ap plication of the brakes. I have also devised an arrangement which serves to equalize the time required for l.)rakere.lease on different' cars of a train. l In brakes oli-the type shown in my afore said patent, the inlet and exhaust valves of the-brake cylinder are controlled by the resultant of three component iressures, towit the train-line and brake-'cylinder pressures 'acting in opposition to a standard pressure. By this means the pressure in the brake cylindersfollows inversely the pressure in the train'line at a ratio dependent upon the mechanicalA advantage ot4 the train-line pressure' with respect to .the bralm-eylimlcr pressure, whereby a given decrease in the former corresponds to a eonsideralrile larger iiicrease inthe latter.. "lurning to the aeconipanying drawing, yrepresents a triple valve embodying my inv vention. It corresiionds to the triple valve oi the ordinary llestivnghouse system 'and is interelningeable therewith, being provided ywith a base plate A designed to be bolted to the auxiliary reservoir in the usual manner. it beingnl'iderstood that my device may be used to advantage in connection with lifest- -inghousc brakes, and controlled by the ordinary Westinghouse engineers valve, although its full value is only realized with my form of engineers valve. The casing of the triple valve is divided horizontally into' three sections c a2 a3, diaphragms C D being interposed between the sections and held in place by the bolts which join the sect-ions together. "lhetwo diaphragms C vand D` are joined kby a hollowv stem E, the upper end of which forms the seat of the valve 7:2 which, together with a similar valvec, is mounted on'the vertical valve stem K. The valve la is the inlet and ,7a2 the exhaust valve of the brake-cylinder, which is in communication Witli the chamber 5 located between the twb valves. A passage 7 admits the brake-cylil'ider pressure from the chamber 5 to the chamber 4. 'where it acts on the upper side of the diaphragm D. The chamber 3 between the two diaphragms is in communication with the train-line by means of the passage 2 which leads trom the chamber l into which the train-line enters. Below the aforesaid stem E is the spring` Gr which acts thereon through a spherical joint and is limited by the stops l il. The spring at its lower end ,bears against the adjusting screw ll.

It will be observed that, as a normal con# dition of equilibrium, both the trainl ine pressure and the brahecylinder pressure the latter acting on a lesser diai'ihragl'n area than the former) cooperate in opposition to the pressure of the standard spring G and holdlooth inlet and exhaust valves closed. Consequently, assuming the parts to be thus in equililirium, any diminution of train-line pressure which may not be counterbalanced by a corr esponding` increase of brake pressure, will disturb the equilibrium and will allow the spring (l to rise and lift-the inlet valve 7c 'from its seat. This will afdmitA pressure trom the chamber 6 which is either the auxiliary-reservoir pressure or thet-rainline pressure) to the brake cylinder' through 'the chamber 5, and this flow from the chamber (3 to the brake cylinder will-continue until the inerease ot' brake pressure is sufincrease in traindine pressure will cause la ,f 1,1()-` compression ot the spring and open 'tlaeeie` liricat to compensate yfor the decrease in haust valve 762, by a depression of its seat, and thereby release the brake pressure through the hollow stein E and the casing ofthe spring G which acts as a inutiied exliaiist outlet; the exhaust How will continue until `the decrease in brake pressure compensates'for the increase in train-line pressure and equilibriuin is again restored and the spring (l closes the exhaust valve 7.22. By this means the brake-cylinder pressure follows inversely the train-line pressure according to a ratio determined by the relative diaphragm areas acted upon by the two pressures.

ln the present application I do not undertake to make any claim upon the construction thus far described.

Between the aforesaid chamber 6 and the train-line chamber 1 I iiitcrpose a eheckvalve I having a hollow stem p with openings therein through which chamber 6 communicates with chamber 9, which in turn, communicates by the passage shown in dotted lines, with a chamber 10. Between the chamber l0 and the chamber 1l is interposed la check-valve P which opens by lifting upward and the chamber 11 communi-. cates with the auxiliary reservoir through the chamber 8. A lsmall feed groove 722 maintains communication betweii the chambers l0 and 1l around the valve P. Vhenever the train-line pressure in chamber l exceeds the auxiliary reservoir pressure in i chamber 6, the valve P lifts and the trainline air then flows to the chamber 6, and feeds the auxiliary reservoir through the hollow stein p, the chamber 9, the chamber l0, feed groove p2, chamber ll, and thence to the auxiliary reservoir through chamber S. Conversely, when the valve P is closed, the auxiliaryereservoir pressure follows the reverse route but has a freer passage', because it lifts the valve P and passesfreely through it. It also acts .downwardly through the hollow stein 77 upon. the valve P tending to close it. When the valve P is lifted the holes in its hollow stein p are nearly closed by the surrounding walls, leaving only a sufficient opening to supply airv to thevfeed groove p2, and this practically shuts volf the tiow from the auxiliary reservoir to the chamber A6, the chamber 6 being then supplied directly from the train line.

It will be understood that normally the three pressures aforesaid are in a state of equilibrium, the train-linepressureand the brake-cylinder pressure balancing the standl ard-spring pressure and maintaining both inlet and exhaust valves of the brake cylinder closed. This is the condition whenthe '..brakes are entirely released and also when they arev applied at some constant pressure determined by the degree of train-line pressure, which in turn is under the control. of

i the engineer. This state of equilibrium is "the brakes depends.

emergency operation and provides for a defi-v is a gradual reduction in train-line pressure,`

as in ordinary service application of 'the brakes, the equilibrium aforesaid will be distributed and the inlet valve 7c leading to the brake cylinder will be opened, but only thev air from the auxiliary reservoir will tlow throughthe open inlet valve to give a brakecylinder pressure.l suti'icient to compensate for the deereasein train-line pressure and thereby restore the equilibrium. On the contrary, if the reduction in the train-line pressure .is made suddenly, the valve-7c will be thrown wide open, 'thereby emptying chamber 6 into the brake cylinder so suddenly as to practically eliminate the pressure in chamber 6 and allow the valve P to rise by virtue of' the train-line pressure beneath it. The rising, of the valve P will, in the way I have described, vshut olf the auxiliary-reservoirair from the chamber G, but admit to that chamber the train-line air. 'It will therefore be the train-line air instead of thc aiixiliary-reservoir air which will rst flow into the chamber 6 and thence into the brake cylinder. This ivill not only give a strong and sudden application of the brakes, but will also tend to deplete the train line and thereby expedite the drop in train-line pressure upon which this Violentapplication of This constitutes my nite serial or successive inflow of train-line and auxiliary-reservoir air to the vbrake cylinder. Uf course the vflow of ,train-line air into chamber G will only continue until the train-line pressure drops sufficiently to allow the auxiliary reservoir pressure, acting downwardly on the valve P through its hollow stein p, to overcome the train-line pressure and close the valve. Then vthe auxiliary reservoir will be the source of supply for the chamber G and the brake cylinder, and the air therefrom will How into the brakes until the brake pressure rises sufficiently' to: re-

store the equilibrium by compensating for the reduction of train-line pressure and so restoringl the balance of pressures which will maintain valves 7c and 7a2, both of them, closed. Upon the, subsequent release of the brakes, by the'restoration of the train-line pressure, the valve P will be .lifted when the train-line pressure rises to a value exceeding that of the somewhat depleted auxiliary reservoir, and thereservoir will be replenished by the passage of the air along the route I have de vscribed including the feed groove pf, and

ioo

when replenished, its pressurewill equal that of the train-line and close the valve P.

In the present case l purpose -to make .claims covering the particular forni and arrangement of the valves P P whereby an over, so as to act in immediate opposition to trailrline pressure for closing the valve P at the point where it is necessary that the auxliary reservoir be called upon to continue the supply to-the brake after the first rush ,of air to the brakes from the train linelias subsided, 'and the train-line pressure on valve Pis reduced below the auxiliary reservoir lpressure thereon.

The next feature of my invention Arelates to a device for equalizing the time required for brakerelease on widely separated cars of a long train. 1t is a Well known feature of vthe lVestinghousesystem that, in restoring the train-line pressure to release the brakes,

the effect isretarded on the more remote cars by the necessity of not only lilling the train-line with air, but also supplying` from the train line the depleted 'auxiliary reser voirs. The Vtrain-line air must first lill the auxiliary reservoirs at the .forward end of the train before its pressure can rise at the rear end. 'This requires considerable time, and until the reservoirs are thus re-iilled, lo compensate for the air drawn from them in the previous application of the brake, the trainline pressure cannot .be fully restored and the brakes thereby released. The forward brakes are in consequence released before the rear ones, with danger under some circumstances of the train pulling apart and with danger of shock to the cars and the freight therein. To obviate this tendency, I provide each of my exhaust valves with what I may call a detainer, which serves to `throttle more or less the outflow yof air through the valve in the event of the valve -be ng lifted suddenly beyond a certain point.

ily this device the exhaust valve will be throttled in proportion to the rapidityof l'uese-:ure-rise in adjacent portion of the train pipe, as compared with the rapidity of press1ire-d1op in the brake cylinders. ln other words this throttling action in my device is not produced merely by the increase of train-line pressure alone, nor it affected in any way by the pressure in the auxiliary reservoir. .No matter how suddenly orV to what degree the exhaust valve. may be opened, no throttling would occur if the brake pressure dropped with equal sudden# ness and to an equal degree, since the equi li'brium would follow synchronously' with -the change in trainfline pressure. The-decrease of the brake-cylinder pressure cannot, however, -follow 1u exact synchronism with the 'increase 1n train-line pressure but lags behind it more or less, and it isthis lag,- ordiiilerential between the rate of train-line increase and brake-cylinder decrease, which gives thefthrottling action upon which l rely. Moreover, the throttling itself serves to increase thelag. 0f course'the throttling ceases in proportion to and as soon as the droppii'ig brake' pressure compensates for and corresponds to the rise'in train-line pressure. lvlereover, the more sudden and extreme `the rise in train-line pressure `the greater will be the th ttling effect, and if die rise in train-line p1 ssure is made slowly so that the brake exhaustfollows' it very closely, as wouldA be the case at the rear cars of thetrain, no throttling` action is' produced.

In along` train the sudden application of the maximum air pressure to the train 'line naturally takes effect first and immediately al the forward end of the train and proccedsalong the train in a sort of wave fashion, there; being a dilferenee in wave-phase at the different cars, and my devise, produres a corresponding difference in the rate of brake release so that the brakes on the lirst and last cars of the train are automatically reduced t any given vpoi'ntsay twenty pounds-at the same instant. The

means by which I accomplish this are extremely simple. consistingrmerely of an enlargement or detainei" S on the lower end of the exhaust valve 7.12 below the seat thereof, which serves, when the valve seat is depressed, to partly re-close and restrict the outflow of'air from the brake cylinderlinlo the atmosphere. The form and size of the detainer lw will determine the degree and time of its restricting` effect. Taking any individiml valve it will be apparent that a sudden increase of train-line pressure' will :anse the compression of the spring G and a corresponding` depression of the seat of the valve 7.12, which will first open the valve as it departs from its seat and then reclose it as the seat approaches the detainer S. lf, however, the sudden compression of the spring` by the increase of Vtrain-line pressure were instantly released by a lcorresponding'v decraise of the 'brake pressure, the valve would be re-closcd by the restoration of the normal equilibrium-` but to the extent that the drop in bralngcyliiider pressure lagsbehind. both by the tln'ottling etl'ect andi by the naturaltime rcoluirelmnt by the outflow of the air, to the same extent will the restoration of equilibrium be retarded, i (')f course if the rise in train-line pressure were so rgradiuil that the outflow o't air from the brake cylini'lerswould keep pace with it there would be merely the normal opening of the valve 71:2 without any throttling of it by` a super-normal movement of the valve seat, and this is the action which takes place at the rear ears of the train.` The valve seat -thus intel-'venes between the seating surface give the tlirottling aforesaid.

What I claim as new and desire to secure by Letters Patent is:

l. The combimxtion in a triple valve, ot inlet and exhaust 'valves t'or the brake cylinder controlled by a balance ot' train-line and brake-cylinder pressures against a standard pressure, means for admitting either auxiliary-reservoir air or train-line air to the brake cylinder according to the rate of train-line decrease, and means for' shutting off the train-line air and admitting the auxiliary-reservoir air by the differential effect of the auxiliary-reservoir and traili-l .lme pressures.,

2. The combination in a triple Valve, of inlet and exhaust valves for the brake cylinder controlled by a. balance of train-line and brake-cylinder pressures against a standard pressure, means for shutting off the auxiliary reservoir from the bra-ke cylinder and connecting the train line thereto according to the'rate of train-line pressure variation, and means for subsequently cutting off. the train-line air and admitting the auxiliary-reservoir air to the Abrake cylinder dependent upon the balance of auxiliaryreservoir pressure against thetr'ain-line pressure.

3. The coi'nbination in artriple Valve, of

inlet and exhaust Valves for the brake cyl-l inder controlled by a balance of train-'line and brake-cylinder pressures against a standard pressure, a chamber communicating with the brake cylinder through the inlet valve aforesaid, a valve between said chamber and the auxiliary reservoir, means for closing the last named valve when the pressure in said chamber falls below the train-line pressure, and means for subsequently opening it when the pressure in said chamber falls below the pressure in the auxiliary reservoir.

4. The con'ibination in a triple Valve, oi inlet; and exhaust valves for the brake cylinder controlledbya balance of train-line and brake-cylinder pressures against a standard pressure, a chamber communicating with the brake cylinder through the said inlet val\'e, a valve for connecting said chamber alternately vwith the auxiliary reservoir and the train line, and a check-Valve between said chamber and the auxiliary reservoir rcstricting the Ilow into, while permitting a free flow out of, the auxiliary reservo-iig,-

5. The combination `in va triple Ivali/e, of

inlet and exhaust valves vfor the brake cylinder controlled by a balance oi train-line and brake-cylinder pressures against a standard pressure, a chamber communicating with the brake cylinder through 'athe said inlet valve, a check-valve between said chamber .and the train line, and a second check- Valve between thev said chaml'mil 'and the auxiliary reservoir.

'6. The combination in a triple valve, of i inlet and exhaust -valves for `the brake cylinder controlled by balance of train-line and brake-cyliiider pressures against a standard pressure, a chamber communicating withthe brake cylinder through thel said inlet. valve, a: check-valve between said chamber and the train line, a second check-valve between the `said chamber and theauxiliary reservoir, and a connection between said chamber and the auxiliary reservoir controlled by the first named check-Valve.

7. The -combination in a triple valve, of inlet and exhaust Valves for the 'brake cylinder controlled by a balance ofV train-line and brake-cylinder pressures against a standard pressure, a chamber communicating with said brake cylinder through the said inlet valve, a checklvalve between said chamber and the train line, a passageway leading` from the said chamber to the auxiliary reservoir and controlled by` the said check-valve, and a second check-Valve located in the said passageway.

tgl-The 'combination'. in a triple Valve of inlet and exhaust valves for the brake cylinder controlled by a. balance of train-line and brake-cylinder pressures against a standard pressure, a chamber communicating with the brake cylinder through the said inlet valve, a check-valve between the said chamber and the train line, and a second check-valve between said cham'ber and the auxiliary reservoir provided with a by-pass 't'ced groove. f

9. The combination in a triple Valve, of inlet and exhaust valves for the brake cyl-v inder controlled by a balance of train-line and bake-cylinder pressures against a standard pressure, and a connection between the train line and the auxiliary reservoir controlled by two check-valves one providedv with a by-pass feed groove.

,10. The combination in a triple Valve, of inlet and exhaust'. Valves for the brake cylinder controlled byl a balance of Vtrain-line and brakecylinder. pressures against a standard pressure, a chamber communicating with the -brake cylinder through vsaid Hinlet valve, a check Valve between said chamber and the train line, a cut oill between said train line and the auxiliary reservoir, and a check-valve between vsaid cut oit' and they auxiliary reservoir.

1l. The combination in a triple valve, of I "inlet and exhaust Valves for the brake cylindirected against the'said check-valve whereby the inflow from the' auxiliary reservoirto the chamber tends to close the said checkvalve.` r l l 12. ln a triple valve for air brakes, the combination with the exhaust valve `of the brake cylinder, and ymeans for throttling for controlling the opening of said exhaust valve according to the rate of increase in train-line ressure. upon the application of the train-line pressure to release the brakes.

15. In atriple valve for air brakes, the combination with the exhaust valve of the brake cylinder ofthrottling devices therefor controlled by the rate of pressureincreas'e in the train line with respect to the rate of pressure decrease in the brake cylinder. l

. 16. In a triple valve for air brakes, the combination 'with the exhaust valve of the brake cylinder, of a graduated release device therefor and a th-rottling device controlled said valve dependent on-the ratio betweenjcby a super-normal opening movement of the the rate of pressure increase in the train line and the rate of pressure decrease in the brake cylinder. l

13. In a triple valve for air brakes the combination' with the exhaust Avalve of the brake cylinder, of means for operating said valve by "the resultant of the train-line and brake-cylinder pressures acting in opposition to'fa standard pressure, and means for throttling said Valve dependent on the ratio between the rate of pressure increase in ythe' train line' and the rate of pressure decrease. in the'brake cylinder. t

.14; faftrlpl Valve for air brakes, ,the coinbmation with the exhaust valve of lhe brakefcylinder, ofoperating devices therefor-controlled by the resultant of the train- -line and brake-cylinder pressures actingnin 'opposition to a standard pressure, and means valvc. I p

17. In a triple valve for air brakes, the combination with the exhaust valve of the brake cylinder having double surfaces, of a valve seat between said surfaces controlled bythe resultant of train line and Abrake cylinder pressures acting in opposition to standard pressure.

18. In a vtriple valve for air brakes the combination with the exhaust valve k2 and its seat, of the detainer S and a valve seat-- intervening between saidl valve and detainer.

In witness whereof I have hereunto set my hand before two subscribing Witnesses this 28th Aday of February, 1907.

JAMES F. MCELROY. Witnesses a* BEULAH CABLE,

ERNEST D. JANSEN.

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