US416516A - Automatic pressure-retaining valve for air-brakes - Google Patents

Description

. (No Model.)

T. P. SWEENEY. 7 AUTOMATIC PRESSURE RETAINING VALVE FOR AIR BRAKES.

No. 416,516. Patented 1300.3, 1889.

UNITED STATES PATENT I OFFICE.

THOMAS P. S'WEENEY, OF SACRAMENTO, CALIFORNIA.

AUTOMATIC PRESSURE-RETAINING VALVE FOR AIR-BRAKES SPECIFICATION forming part of Letters Patent No. 416,516, dated December 3, 1889. Application filed December 8. 1888- Serial No, 293,010. (No model.)

To all whom it may concern:

Be it known that I, THOMAS P. SWEENEY, of Sacramento, Sacramento county, State of California, have invented an Improvement in Automatic Pressure -Retaining Valves for Air-Brakes; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to improvements in air-brakes; and it consists of what I term an automatic pressure-retaining valve, which may be operated in connection with the resfixed upon each car, having avalvemechanism,

which is called a triplevalve', through which air is admitted to the reservoir, and by which it is also admitted from the reservoir to the brake-cylinder by the reductionof the pressure in the train-pipe but when it is necessary to replenish the auxiliary reservoir it is necessary to temporarily out off the communication between this reservoir and the brakecylinder, so that the latter is without pressure while the reservoir is being replenished, and

the movement of the valves to .connect the reservoir with the train-pipe allows the'air to escape from the cylinder. When this occurs upon heavy downgrades, it is a dangerous thing, because the train will gain such momentum in a very short distance that it will be almost impossible to handle it and again check it. My invention is designed to overcome this difficulty; and it consists in the employment of what I term a pressureretaining valve, which regulates or prevents the escape of air from the brake-cylinder while the train-reservoir is being replenished.

In the drawings, A is the train-pipe, through which the air passes in the direction shown by the arrows.

B is a triple-valve mechanism, so called.

C is an auxiliary reservoir, and D is the brake-cylinder. These portions of the apparatus being well shown in the patents already issued and in use upon what is known as the Westinghouse system, I shall not further describe them in this place.

E is a supplemental cylinderin which is fitted a cylindrical valve F. This cylinder is placed in a vertical position and has an opening in its top and also in its bottom. The opening in the bottom of the cylinder is connected with the train-pipe A, so that the pressure from said pipe may act upon the bottom of the piston-valve F to raise it, the interior of the cylinder being enough longer than the valve to allow it a certain amount of movement longitudinally within the cylinder. At the upper end of the supplemental cylinder is an extension forming a chamber E, Which is connected by a pipe L with the auxiliary or car reservoir. A horizontal passage J is made transversely across the valve F, and holes are made in opposite sides of the cylinder E, which holes correspond with the passage in the valve when the valve is at its lowest point; but when the valve is raised its passage will be carried above the line of the holesin the sides of the cylinder and will thus cut off communication through them.

T is the discharge passage or opening in the triple-valve chamber, through which air from the brake-cylinder is ordinarily allowed to escape by the movement of the triple valve, which allows the auxiliary reservoir to be recharged. Above the upper end of the cylinder E is an extension, forming a chamber E,

having within it a piston N, which is'provided with a stem M, extending downward through the head or diaphragm which separates the chambers E and E. This opening T, as ordinarily employed, allows the air to escape from the brake-cylinder D when the triple valve is so moved as to make connection between the train-pipe A and the auxiliary reservoir 0; but in the present case this escape-opening T is connected by a pipe at directly with the side of the valve-chamber E and the transverse passage J through the valve F.

V is the pipe which connects the brakecylinder with the triple-valve chamber, and through which, when the valves are in proper position, air passes from the reservoir 0 to the brakecylinder 1), so as to apply the brake. In the ordinary construction, when the triple valve is moved so as to admit air from the train-pipe to the reservoir, it also allows air to escape from the brake-cylinder through the pipe V and the opening T.

The operation of the device will then beas follows: Air is pumped into the reservoir upon the engine to a pressure, say, of one hundred pounds, and by means of the engineei"s valve it is allowed to pass through the train-pipeA into the auxiliary reservoirs C,which are beneath each car. The triple-valve mechanism, which is already in use, and is therefore not here described, is so arranged that when the pressure from the train-pipe A is admitted into the triple-valve chamber 13 it moves the valves so as to open communication directly with the reservoir 0, so that air may flowinto this reservoir up to any desired pressure. This movement of the valve alsoopens comllllllllOittIOll between the brake-ey1inderD and the opening '1, which is ordinarily anescape or'discharge passage, but which in my inventioneommunicates through the pipe awith the side of the cylinder-E, as above described. Nowqwhen it is desired to applythe brake, suppose the pressure in the reservoirC to stand at seventy pounds. By means of the engineers valve the pressure in the trainpipe'may bereduced to something less than the pressure in the reservoir. The triple valve will then be moved so as to open communication between the reservoir 0 and the brake-cylinder D, and any required pressure may be admitted into the cylinder-D. "hen running down grades the leakage and gradual escape of the air will reduce the pressure in the auxiliary reservoir 0 until it is below what is necessary for the proper control of the train. It is then necessary to resupply the auxiliary reservoirs from the engine-reservoir by 'means of the engineers valve. Air is allowed to pass through the train-pipe A, and acting upon the valves in the chamber 13 communication is opened between the trainpipe and the reservoir C, and at the same time communication is opened between the brake-c'ylinderD and the discharge openi-ng '1. As formerly arranged the air would be allowed to escape from the brake-cylinder, and the train would be temporarily out of control of the brakes and would be liable to attain a dangerous speed. In my invention, however, the pressure in the train-pipe, aeting through the pipe G upon the bottom of thevalve F, forces this valve up until the passage J in the valve is out of line with the pipe a and the openings in the sides of the valve-chamber E. The pressure in the brakecylinder is thus retained, because this valvc' cuts off the escape of the air through the hole T. \Vhen the pressure in the reservoir C is such as to balance the pressure in the trainpipe A, it acts through the pipe L, which connects the upper cylinder E with the reservoir G, and pressing upon the piston M forces it down, and through the stem M the valve F is also'forced down until the passage J is in line with the pipe or, when air maybe allowed to escape from the brake-cylinder D to any desired degree. By reducing the pressure in the train-pipe to less than that in the reservoir C the valves in the chamber B will again be moved so as to admit air into the brakecylinder D. The amount of pressure in the train-pipe and this cylinder is controlled by the engineefis valve in the wellknown manner.

Inorder to insure theprompt movement of the valve'or piston F as soon as the pressures in the auxiliary reservoirand the train-pipe are equalized, I have shown a light spring I), so disposed in the upperpart of the valve chamber E as to pressupon the top of the valve F. g

I have shown the valve chamber E at some distance from themain valve-chamber 13,1301 convenience in describing; butin practice it maybe placed in close eonnectionwitlrthe discharge-opening T, so as to make-the" whole compact.

The object of the device is to keep thcb 'akes applied while the train-reservoirs are being recharged without in any way disturbing the valve mechanism atpresenirin useand by an exterior supplemental device.

I do not wish to limit myselfto thespecilic arrangement and construction of parts herein shown, as thesame may be modified or changed without departing from'the spirit of myinvention.

Having thus described in y invention, what I claim as new, and desire to secure bylietters Patent, is-

1. The improvement in automatic air-brake mechanism, consisting ofa cutoff valve connected with the triple-valve mechanism and exterior thereto, said valve acting to close the escape-passage from the brake-cylinder by the increase of train-pipe pressure.

2. The combination, with the auxiliary reservoir, brake-cylinder, and intermediate triplevalve mechanism of an automatic air-brake, of a cylindrical valve-chamber having openings made in its opposite sides in line with each other, a piston fitted to move within said cylinder and having a hole made transversely through it corresponding with the holes in the sides of the cylinder when said piston is at one end of its stroke, a pipe connecting this end of: the cylinder with the train air-supply pipe, a second'pipe connecting the opposite end "of the cylinder with the auxiliary reservoir, and a pipe connecting one of the openings in the side of the valve-cylinder with the escape-passage at the triple-valve chamber,

whereby said passage is closed by the upward movement of the piston within the supplemental cylinder, substantially as described.

3. A supplemental cylindrical valve-chamher having openings in the opposite sides, a vertically-moving piston fitted therein and having a transverse opening corresponding with the openings in the sides of the chamber, in combination with the brake-cylinder, auxiliary reservoir, train-pipe, and triple-valve mechanism connected therewith, a pipe connecting one 01": the openings in the side of the supplemental cylinder with the escape-passage of the triple-valve mechanism, a second pipe connecting the bottom of said cylinder with the train-pipe, and a pipe connecting the top of saidcylinder With the auxiliary reservoir, substantially as described.

4. The automatic air-brake mechanism, consisting of the auxiliary reservoir, the brakecylinder, and the valves, whereby the supply and discharge of air is effected, in combination with a supplemental cylinder, apiston reciprocating therein, pipes connecting the opposite ends of said cylinder with the train-pipe and auxiliary reservoir, a passage through said reciprocating piston, and corresponding openings in the side of the cylinder, one of which is connected with the auxiliary-reservoir valve mechanism, so that the movements of the supplemental piston in its cylinder will close or open the passage and simultaneously close or open the discharge from the brakecylinder, substantially as dscribed. 5. The automatic air-brake mechanism, consisting of an auxiliary reservoir, the brakecylinder, and the triple valve mechanism whereby the supply and discharge of air is effected, a supplemental cylinder having apiston reciprocating therein and the opposite ends of said cylinder connected with the trainpipe and auxiliary reservoir, a transverse opening through said piston, and corresponding openings in the sides of the supplemental cylinder, together with a supplemental piston fitted in the upper part of the supplemental cylinder, having a stem extending downward and pressing upon the top of the main piston, and a spring surrounding said stem and acting ,upon the main piston, substantially as described.

In Witness whereof I have hereunto set my hand.

THOMAS P. SWEENEY.

WVitnesses f S. H. NOURSE, H. 0. LEE.

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