US1083521A - Pneumatic brake. - Google Patents

Description

P. J. GHAPSAL & A. L. E'. SAILLOT. PNEUMATIG BRAKE.

APPLICATION FILED MAY zo, 1912. 1,083,521 Patented Jan. 6, 1914.

s SHEETS-SHEET 1.

`F. J. CHAPSAL L A. L. E. SAILLOT.

PNEUMATIG BRAKE.

APPLICATION FILED MAY 20, 1912.

5 SHEETS-SHEET 2.

IHEJ

COLUMBIA PLANOURAPH Co.. WASHINGTON, D. c.

Patented Jan.6,1914.

F. J. CHAPSAL & A. L. E. SAILLOT.

PNEUMATIG BRAKE.

APPLICATION FILED MAY zo, 1912.

Patented J an. 6, 1914.

5 SHEETS-SHEET 3.

Inventor.;

Witnesss.

ujmw- PH CD., WASHINGTON. DA C,

P. J. CHAPSAL & A. L. E. SAILLOT.

PNEUMATIG BRAKE.

APPLIOATIQN FILED MAY 2o, 1912.

1,083,521 Patented .1211.6, 1914.

5 SHEETS-SHEET 4.

U Z'nvenors,

Witnesses.

COLUMBIA PLANocmAPH co.. WASHINGTON, D. c,

I. J. CHAPSAL & A. L. E. SAILLOT.

PNEUMATIG BRAKE.

APPLIOATION FILED MAY 2o, 1912.

Patented Jah. 6, 1914.

6 SHEETS-SHEET 5.

1 mors 4am-WW All., gx

Witnesses.

COLUMBIA PLANOGRAPH 60.'. WASHINGTON. D.

TNTTED STATES PATENT FFTCE.

FRANQOIS JULES CHAPSAL AND ALFRED LOUIS EMILE SAILLOT, OF PARIS, FRANCE.

PNEUMATIC BRAKE.

noeasai.

Specification of Letters Patent.

Patented Jan. 6, 1914.

Application filed May 20, 1912. Serial No. 698,493.

To all whom t may concern.'

Be it known that we, FRANQoIs JULES Crnxrsai. and ALFRED Louis EMILE SAILLo'r, citizens of the French Republic, residing at Paris, Department of the Seine, in France, have invented certain new and useful Improvements in and Relating to Pneumatic Brakes; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to pneumatic brakes and has for its object to provide a doubleacting pneumatic accelerator for compressed air brakes applicable to long railway trains provided partially or wholly with a pneumatic brake of any kind.

The double acting accelerator in accordance with this invention comprises a pneumatic relay interposed between the train pipe and the distributer and connected with a special reservoir which supplies the distributer at the moment of releasing the brake. This accelerator which is actuated by the pressure of the train pipe completely cuts off this pipe from the distributer during the braking and is protected from the variations in pressure which the operation of the distributer produces in the local branch.

The apparatus comprises two chambers each divided by pistons or diaphragms into two superposed compartments; each of these compartments is in constant communication one with the other. Furthermore the lower compartments are permanently connected with the train pipe while the upper compartments are connected with the pipe by a valve which only establishes communication above a certain pressure. The diaphragms or pistons displaced by the variations of pressure in the train pipe control various valves which when the brakes are released place the upper compartments in communication with the special reservoir and when the brakes are applied place the two groups of compartments in communication with the atmosphere. In this manner any variation of pressure in the train pipe produces in each branch a variation of pressure in the same direction and of the same magnitude.

The variations of pressure produced by the driver, in the train pipe which is isolated during the braking in order to render the doubleacting accelerators operative are thus rapidly transmitted to the rear of the train whatever the number of vehicles it :may comprise which are provided with braking members. It is transmit-ted in the same manner if all the vehicles are equipped with only a plain pipe. The rapid action in all the braking phases is consequently independent of the number of vehicles provided with the continuous brakes.

In the accompanying drawing: Figure 1 is a cross section of an accelerator in accordance with the invention. Fig. 2 is a general view showing the application of the foregoing accelerator to the Chapsal and Saillot brake forming the object of American Patent No. 802,913 of the 28th December, 1904. In this case the regulator-reservoir of the distributer is employed as the brake releasing reservoir. Fig. 3 is a cross section of the modified compressed air accelerator combined with the braking members of a two-chamber brake of the Venger type without dist-ributer. Fig. 4f is a cross section of the compressed air accelerator modiiied and combined with the braking members of a two-chamber brake with reducer of the Lipkowski type without distributer. Fig. 5 is a cross section of the accelerator for a vacuum brake combined with the braking members of an automatic vacuum brake of the Clayton type without distributer, that is to say without a ball valve.

The body l of the accelerator (Fig. 1) comprises two housings divided into four compartments 2, 21, 3, 31 by diaphragms or pistons 5 and 6 respectively comprising control rods 7 and 8. The rod 7 serves to act when the diaphragm is displaced (as is hereinafter explained) upon a valve 9 or upon a valve 10 arranged in the body of the accelerator above and below the diaphragm or piston 5. The valve 9 may place the compartment 21 in communication with a passage 11 opening above a valve 12 held upon its seat by a spring 13 and which serves in certain conditions to place the conduit 11 in communication with a conduit 14 connected with the special brake releasing reservoir. This reservoir in the Chapsal and S'aillot brake in accordance with American Patent No. 802,913 may be the regulator reservoir F which governs the distributer B.

By means of a passage 15 the valve 10 is able to place the lower compartment 2 directly in communication with the atmosphere or with a chamber 4 provided with a small exhaust aperture 26. The rod 8 which moves integrally with the diaphragm 6 moves in a housing in the upper part of the accelerator body and at its upper part carries a valve 16 which when the diaphragm is shifted downward enables the upper compartment 31 to be placed in communication with the outer air through the oritices 17 formed in the guide cap of the rod 8. By means of the pipe 18 the compartment 31 communicates with the under side of the piston of the distributer of the Chapsal and Saillot brake. At 19 the train pipe opens into the accelerator inside which it presents two branches 20 and 21 which communicate respectively with the lower compartments 2 and 3. By the intermediary of a valve 22 the pipe 19 can also communicate with a space 23 placed by the pipes 24 and 25 in communication with the compartments 21 and 31. The general view Fig. 2 is a diagrammatic representation of the application of the double-acting accelerator to the Chapsal and Saillot brake and ot' the pipes placing this accelerator in communicationy with the train pipe A the distributer B and its regulating parts C, the brake reservoir DJ the brake cylinder E and the regulator reservoir F which controls the distributer. For the sake of clearness this diagrammatic figure illustrates the accelerator branched ofi" the train pipe but it may be mounted directly on this pipe.

The accelerator' operates in the following manner: Normally the compressed air is sent by the driver into the train pipe A. As soon as the pipe is charged the air reaches the accelerator on each vehicle at 19 and is conducted respect-ively through the pipes 20 and 21 to the lower compartments 2 and 3 and lifts the diaphragms 5 and 6. The valve 22 is held upon its seat by a loaded spring which balances beneath this valve, a certain pressure which can be regulated at will (0.100 of a kg. per cm2 for example) to prevent inopportune applications of the brake during running, owing to slight leakages from the train pipe not compensated Jfor by the automatic supply valve of the drivers cock. This valve first of all remains closed. The valve 9 is lifted by the control rod 7 of the diaphragm 5 but Ithe valve 12 remains applied to its seat and interrupts all communication between the pipe 11 and the pipe 14 communicating with the regulator reservoir F; as regards the valve 16 it is applied to its seat by the rod 8 which is moved upward by the diaphragm 6. As soon as the pressure in the train pipe, and

v consequently in the lower compartments 2 and 3 is sutlicient to overcome the resistance of the valve 22 the latter rises and the air from the train pipe passes into the upper compartments 21 and 31 through the pipes 24 and 25; then through the conduit 18 it is conducted beneath the piston of the distributer B. Consequently the regulator reservoir F is normally charged through the supply channel of the piston of the distributer, but at a pressure approximately 0.100 of a kg. lower than that of the train pipe, this difference corresponding to the load of the spring of the valve 22 while the valve 12 remains closed Vin such a manner as to prevent the regulator reservoir F from being charged directly through the pipe 14.

in order to apply the brakes a local reduction sufficient to bring the lower compartment 2 of the double-acting accelerator of the first vehicle to a pressure lower than that of the compartment 21 is produced by means of the drivers cock; that is to say it is necessary to produce a reduction greater than 0.100 of a kg. per cm2. The diaphragm 5 is then shifted downward, the valve 9 closes vunder the `influence of its counter spring and the valve 10 (the spring of whichis loaded in such a manner as to maintain this valve closed at the maximum pressure of the train pipe) is displaced and enables the air of the train pipe to pass through the pipe 15 into the expansion pocket or cavity 4 or directly into the atmosphere. Consequently a sudden tall of pressure is produced which causes the depression ot' the diaphragm 6 and the opening of the valve 16 which then permits of the direct passage into the atmosphere through the orifices 17, of the air which acts beneath the piston of the distributer B and that which is contained in the compartments 21 and 31, these compartments being in direct communication by means of the pipes 24 and 25. The volume of the pocket 4 is such as to produce beneath the piston of the distributer a sudden reduction sutlicient to produce the immediate depression of this piston. As soon, however, as the pressure in the lower compartments 2 and 3 again becomes greater than that existing in the upper compartments 21 and 31 the valves 10 and 16 reclose while the expansion pocket is exhausted through a small orifice formed at its upper part. In this manner a first slight application of the brakes is obtained which is transmitted rapidly to the rear of the train because the train pipe being completely isolated during the braking, from the branches proceeding to the distributer, the partial reductions of this pipe produced solely by the drivers cock are transmitted with an accelerated velocity whatever their intensity may be to the rear of the train in the same man ner as if the train were composed only of unbraked vehicles and merely provided with plain pipes. The accelerated transmission of the partial reduction is therefore rendered rapid by the supplementary reductions produced by the accelerators upon the vehicles provided with braking members. lf after one or more successive brakings the train pipe is again charged to release the brakes partially or completely the same pressure prevails at this moment in the tour compartments 2 21, 3 31. Consequently only a small rise of pressure in the train pipe transmitted rapidly to the rear of the train owing to the insulation of this pipe is suihcient to lift the diaphragm 5 of the accelerator while the valve 16 remains closed and vigorously applied to its seat. On the other hand the valve 9 is opened by the operating rod 7 of the diaphragm 5 and the Valve 12 is lifted in opposition to the action of its counter spring 13 by the air of the regulator reservoir F, the pressure of which is greater than that of the air in the compartments 21 and 81. The regulator reservoir is thus in direct communication with the compartments 21 and 31 and consequently with the lower part of the distributer and with the moderator. This low of air from the regulator-reservoir into the branch proceeding to the distributor, is caused to cease as soon as the pressure in the branch and in the compartments 21 and 31 becomes equal to that of the wholly or partially recharged train pipe, because the lifted diaphragm 5 which holds the valve 9 open, resumes the horizontal position which immediately produces the closing of this valve. The recharging of the branch proceeding to the distributor of each vehicle which is eifected by the regulator reservoir, therefore takes place in the same manner as if it were supplied by the train pipe because a rise of pressure in the branch at once corresponds to each increase of pressure in this pipe, the rise of pressure in the branch being equal to that in the train pipe.

rEhe release of the brakes is doubly accelerated because the intensity of the brakw ing in the Chapsal and Saillot brake is at all times regulated by the special moderating member of the distributer in accordance with the diiierence of the pressures of the air in the regulator reservoir and of the air in the train pipe. It follows from this that the release is completely finished at the moment at which equality of pressure is established between the regulator reservoir and the branch, that is to say between the regulator reservoir and the train-pipe, the result being that the increase of pressure needed in this pipe for completely releasing` the brakes, depends upon the excess pres sure or the air in the regulator reservoir and the smaller such excess pressure in the regulator reservoir is the smaller will be the increase of pressure needed in the train pipe.

it is obvious that in order to re-charge the branch proceeding to the distributor ot each vehicle it would be also possible to employ a separate air reservoir supplied during running in the same manner as the regulator reservoir but in this case the benei'it of the supplementary acceleration of tne release, due to the expansion of the regulator reser- Voir in the branch proceeding to the distributer would be lost. The employment of a separate reservoir, would, however be necessary with brakes of the TiVestinghouse type in which the auxiliary reservoir which controls the triple valve also supplies the brake cylinder, because until the maximum application of the brakes has been attained there is always after each braking, equality of pressure between the air of 'the train pipe and the auxiliary reservoir. The latter could not therefore be utilized for recharging the branch proceeding to the triple valve until after complete application of the brakes and when the pressure in the train pipe has fallen below the pressure corresponding to the maximum application of the brakes.

It has been seen that throughout the entire duration of the braking, the train pipe is completely isolated by the two diaphragms and the non-return valve of the double-act ing accelerator from the branch proceeding to the distributer of each vehicle, this peculiarity which constitutes one of the main characteristics of the present invention presents great advantages from the point o't view of rapidity of transmission to the rear of the train of the slight reduction produced by the driver for applying the brakes mod erately.

The movements of the liquid stream in the train pipe are completely protected :trom the variations oit' pressure caused by rendering the distributer operative, which variations o pressure constitute the main cause of retardation of the transmission throughout the entire length of the train of the variations of pressure produced in this pipe. lt is to be noted that the double acting accelerator prevents any flow of air from the branch to the train pipe during slight applications of the brake, since the accelerator causes the air from the branch to be discharged directly to the exterior. rlhe small reductions produced in the train pipe are then transmitted rapidly to the rear of the train whatever their intensity may be and whatever may be the number of vehicles provided with braking members and this in the same manner as it the entire train were composed only of vehicles provided with a plain pipe; this rapidity of transmission is therefore independent of the number of vehicles provided with braking members and it is further increased by the additional ren ductions produced directly by a double acting accelerator beneath each vehicle provided with the braking members.

In Fig. 3 which represents a cross section of the foregoing accelerator modified, and

combined with the braking members of aV compressed air brake of the Venger type without distributer, it will be seen that the accelerator branch which was connected with the distributer of the Chapsal and Saillot brake is now connected by the intermediary of a special relay and of the pipe 44 with the chamber E1 of the brake cylinder while the second chamber E2 is directly connected by the pipe 43 with the space located above the valve 9. This special relay which is intended to render the operation of the accelerator completely independent of the period of time necessary for attaining the maximum application of the brake (which period corresponds to the complete exhaustion of the compressed air from the chamber E1) is formed by a small chamber G in which a piston with cupped leather 48 moves; this piston comprises a pin 49 which according to the position of this piston closes or establishes communication between the lower part of the chamber' G and the atmosphere through the passage 50.

The operation of the brake combined with the accelerator is as follows: When the train pipe A is charged the air of this pipe passes through the passages 20 and 2l beneath the diaphragms 5 and 6 which it lifts. The valve 9 opens while the valve 16 is strongly applied to its seat; then as soon as the pressure in the pipe is suflicient to lift the valve 2Q held upon its seat by a loaded spring in such a manner as to balance of approximately 0.100 of a kg. acting beneath this valve7 the latter rises and the two brake chambers E1 E2 are charged simultaneously on the one hand through the passages 24, 25 the lifted valve 9 and the pipe 43, and on the other hand through the passages 24, 25, 18 and the chamber G, the air passing around the cupped leather of the piston and the pipe 44 while the pin 49 pressed upon its seat closes the communication with the outer air through the passage 50. There is equilibrium of pressure in the two chambers and the piston of the brake cylinder occupies the position indicated in Fig. 3, but this pressure is less by approximately 0.100 of a kg. per cm2 than in the train pipe.

In order to apply the brakes a local reduction is made by means of the drivers cock in the train pipe which is greater than 0.100 of a kg. the diaphragm 5 is then displaced downward, the valve 9 closes under the action of its counter spring and the double valve 45, 451 (the spring r of which is loaded in such a manner as to maintain the valve 45 closed at the maximum pressure, of the train pipe) is depressed and applied to its lower seat, the valve 451 then closing communication between the expansion pocket 4 and the atmosphere through the orifice 47 which enables the air of the train pipe to lill the pocket 4 immediately. A sudden fall ofA pressure is therefore produced in this pipe which immediately deprcsses the diaphragm 6 and opens the valve 16 thereby permitting of the escape into the atmosphere through the orifices 17 of the air from the upper part of the chamber G and that from the two chambers located above the diaphragms but as soon as the pressure beneath these diaphragms again becomes greater than the pressure existing above, the double valve 45V, 451 resumes its initial position and the valve 16 again closes while the expansion pocket is exhausted through 47. The pressure beneaththe piston 48 in direct communication with the chamber E1 through the pipe 44 is then preponderating. This piston rises permitting of the discharge of the air from chamber E1 to the exterior through the passage 50 until the air of this chamber again assumes the same pressure as that of the chambers located above the diaphragms, whereupon the piston 48 descends under the influence of a counter spring (not shown) and the pin 49 depressed into its sea-t cuts olf communication with the exterior.

The period of time necessary for the operation of the accelerator is therefore independent of the period of time necessary for obtaining the maximum braking eect because it is only necessary to reduce to zero the air pressure of the chamber G located above the piston 48. Tt is therefore possible by giving an appropriate section to the extremity of the exhaust pipe 50 to/regulate at will' the period of time necessary for obtaining the maximum braking effect so that merely by operating a three-way cock arranged at the end of the pipe 50 this period can be regulated eitherfor passenger trains or for freight trains which require a much longer period. lf after one or more successive brakings the tra-in pipe is recharged so as to release the brake partially or wholly the pressure is then the same above and below the diaphragms; all that is necessary therefore is a small rise of pressure in the train pipe rapidly transmitted to the rea-r of the train owing to the complete isolation of this pipe in order to lift the diaphragm 5 of the accelerator while the valve 16 remains closed and applied to its seat. On the other hand the valve 9 is opened in such a manner that the chamber E2 is in direct communication with the chamber E1 through the upper chambers of the diaphragms and through the chamber 4; this flow of air from t-he chamber E2 into the chamber *1 is stopped as soon as the pressure in the chambers E2 and G and in theupper chambers of the diaphragms becomes equal to that of the train pipe partially or wholly recharged because the. raised diaphragm 5 vwhich keeps the valve 9 open resumes the normal position which immediately causes Athe closing of this valve. The re-charging of the chamber E1 through the chamber E2 is therefore effected in the same manner as if it were supplied through the train pipe, because to each increase of pressure in this pipe, there immediately corresponds a rise of pressure of the saine magnitude in the chamber El. The release of the brakes is therefore doubly accelerated because the intensity of the braking in brakes of the l/Venger type is at all times proportionate to the difference of the pressures of the air acting upon the two faces of the piston of the brake cylinder. It follows from this that the release is completely finished at the moment at which equality of pressure is established between these two chambers that is to say between the train pipe and the chamber E2 expanded into the chamber E1 so that the extent of the re-charging of this pipe for obtaining complete release of the brakes is smaller in proportion as the pressure of the air in the chamber E2 expanded into the chamber E1 becomes smaller.

It is obvious that in order to re-charge the chamber E1 a separate air reservoir might be employed; this reservoir being supplied during running in the same manner as the chamber E2 but in this case the benefit of the supplementary acceleration of the braking due to the expansion of this chamber into the chamber E1 would be lost.

Fig. 4 is a cross section of the compressed air accelerator modified and combined with the parts of a two chamber brake with re` ducer of the Lipkowski type and without a distributer. In this case only the modifications introduced into the special relay which renders the operations of the accelerator ndependent of the period of time necessary for obtaining the maximum braking will be described, these modifications being necessitated by the addition of the third chamber which forms the reducer.

The lower part of the chamber G is as before, connected with the chamber E1 by a pipe 44 and with the reducer by a second pipe 55 supplied through a passage 54. The rod of the piston 48 is connected with a pin 49, the connection allowing an amount of lost motion corresponding to the stroke of a slide valve 52 directly actuated by this rod. In the position shown in Fig. 4 which correspends to normal running with brakes released, this slide valve 52 closes a passage 58 opening into the atmosphere. The chamber K of the reducer is supplied at the same time as the chambers E1 and E2 and at the same pressure.

In order to apply the brakes a reduction greater than 0.100 of a kg. is formed in the train pipe and this reduction owing to the action of the accelerator permits an escape of air from the chambers over the diaphragms and from the chamber G, which escape ceases as soon as the pressure in these chambers is equal to that in the train pipe; the piston 48 is then at once lifted. In the first portion of its stroke it displaces the slide valve 52 which places the passage 53 and consequently the chamber K of the reducer in direct communication with the atmosphere through the passage 52. This chamber empties immediately and the piston of the brake cylinder brings the brake shoes into contact with the wheels while the air in the chamber E1 is passing into the chamber E2 through a non-return valve which is comprised in the Lipkowski brake. The pin 49 is then lifted by the extremity of the piston rod 48 and the chamber E1 discharges into the atmosphere through the passage 50 until the moment at which its pressure becomes equal to that of the upper chambers of the diaphragms and of the chamber G; the piston 48 is then depressed under the influence of its spring and the pin at once recloses.

When the brakes are released the chamber E2 as before is placed in communication with the chamber E1 and also with the chamber K of the reducer. The brakes are released in the same conditions as with brakes of the Wenger type.

Fig. 5 is a cross section of the accelerator for vacuum brakes combined with the parts of an automatic vacuum brake of the Clayton type without distributer, that is to say, without a ball valve.

The lower chamber E1 and the upper chamber E2 of the brake cylinder are connected with the upper compartment 31, the former directly through the pipe 44 and the passages 18 and the latter through the pipe 43 and the valve 16.

When a reduction of pressure takes place in the train pipe A the valve 22 held upon its seat by a loaded spring, first of all remains closed and the diaphragnis 5 and 6 are depressed. As soon, however as the reduct-ion of pressure is sufficient to overcome the resistance of the loaded spring this valve opens in such a manner that a vacuum slightly less than that in the train pipe is established in the upper chambers of the diaphragms, and consequently in the two chambers E1 and E2 of the brake cylinder, because the valve 16 is open; during` this time the valve 28 is closed by atmospheric pressure as is also the valve 10 which is pressed upon its seat by the spring r loaded in such a manner as to balance the atmospheric pressure acting beneath this valve.

In order to apply the brakes a local readmission of air is produced by means of the drivers ejector and this is transmitted rapidly to the rear of the train in the isolated train pipe, the diaphragins 5 and 5 are moved upward, the valve 10 is pressed upon its seat maintaining the vacuum in the upper chamber E2 of the piston of the brake cylinder while the lifted valve 10 places the expansion pocket 4 in direct communication with the train pipe which causes the valve 28 to rise. The outer air is then introduced into the upper chambers of the diaphragms through the orifices 29 and thence passes through the pipe 44 beneath the piston of the brake cylinder which is lifted; this readmission of air is stopped as soon as the vacuum above the diaphragm becomes equal to that o-f the train pipe because the diaphragm 5 which maintained the valve 18 lifted resumes the normal position thereby at once closing this valve. The introduction of air beneath the piston of the brake cylinder is therefore effected in the same manner as if the lower chamber E1 were supplied from the train pipe because to each reduct-ion of the pressure of this pipe there immediately corresponds a reduction of the same magnitude of the pressure in the upper chambers of the diaphragms and consequently of the pressure in the chamber El.

If after one or more applications of the brake a reduction of pressure is again caused in the train pipe for partially or completely releasing the brake, the degree of pressure is then the same above and below the diaphragms. Consequently all that is necessary is a slight reduction of pressure in the train pipe rapidly transmitted to the rear of the train, owing to the complete isolation of this pipe in order to depress the diaphragm 6 of the accelerator, which then places in direct communication through the open valve 16, the two chambers E:L and E2 of the brake cylinder. This communication is cut off when the degree of pressure in the lower chamber E1 of the piston becomes equal to that in the train pipe. The restablishment of the vacuum beneath the piston of the brake cylinder therefore takes place in the same manner as if the train pipe were directly connected withj the chamber E1 because to each rise of the vacuum of the train pipe there immediately corresponds a rise in the Vacuum in the chamber E1. The release is doubly accelerated because the vacuum of the upper chamber E2 of the piston diminishes simultaneously with the increase of the vacuum of the lower chamber E1, the complete release being obtained at the moment at which there is equality of vacuum on the two faces of the piston. It is therefore by restablishing this reduced vacuum in the train pipe that the brakes are completely released.

l/Ve claim:

1. In a pneumatic braking system for railway cars andthe like, the combination with vthe train pipe and the local branch of each car, of an accelerator disposed in said branch, said accelerator comprising a casing, diaphragms disposed therein subject on their one face to the pressure of the train pipe, and valve mechanism controlled by said diaphragms to control the passage of air to and from the local branch.

2. In a pneumatic braking system for railway cars and the like, the combination with t-he train pipe and the local branch of each car, of an accelerator disposed in said branch, said accelerator comprising a casing, diaphragms disposed therein subject on their one face to the pressure of the train pipe, and means whereby said diaphragms control the actuation of the brakes.

3. In a pneumatic braking system for railway cars and the like, the combination with the train pipe and the local branch of each car, of an accelerator disposed in said branch, said accelerator comprising a casing, diaphragms disposed therein subject on their one face to the pressure of the train pipe, means whereby one of said diaphragms co-ntrols the exhaust from the local branch, and means whereby the other diaphragm controls admission of air to the local branch.

4. The combination with the pneumatic brakingsystem of railway cars and the like, of an accelerator disposed between the braking mechanism of each car and the train pipe, said accelerator provided with diaphragms ,subject on their one face to the pressure in the train pipe, and means dependent upon the actuation of said diaphragms by the pressure of the train pipe to effect the braking of the car independent of the train pipe pressure whereby braking is accomplished simultaneously and uniformly throughout the length of the train.

5. In a pneumatic braking system for railway cars and the like, the combination with the train pipe and the local branch of each car, of an accelerator disposed in said' branch, said accelerator comprising a casing, diaphragms disposed therein subject on their one face to the pressure of the train pipe,y and valve mechanism controlled by said diaphragms to control the passage of air from the train pipe and to and from the localV branch.

tures, in presence of two witnesses.

FRANCOIS JULES CHAPSAL. ALFRED LOUIS EMILE SAILLOT.

Witnesses H. C. COXE, GrnouensV BoUJA.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C.

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