US766642A

US766642A - Pressure-retaining device for fluid-pressure brakes.

Info

Publication number: US766642A
Application number: US18751704A
Authority: US
Inventors: Frederick Mertsheimer
Original assignee: Individual
Current assignee: Individual
Priority date: 1904-01-02
Filing date: 1904-01-02
Publication date: 1904-08-02
Anticipated expiration: 1921-08-02

Description

No. 766,642. PATENTED AUG. 2, 1904. F. MEBTSHBIMER.

PRESSURE RETAINING DEVICE FOR FLUID PRESSURE BRAKES.

APPLICATION FILED JAN. 2, 1904.

NO MODEL. 2 SHEETS-SHEET 1.

814mm foz 71 lar (Mum Q14 Jad "cana PATENTED AUG. 2, 1904.

I. MERTSHEIMER. PRESSURE RETAINING DEVICE FOR FLUID PRESSURE BRAKES.

APPLICATION FILED JAN. 2. 1904.

2 SHEETS-SHEET 2.

N0 MODEL.

UNITED STATES Patented August 2, 1904.

FREDERICK MERTSHEIMER, OF DENVER, COLORADO.

PRESSURE-RETAINING DEVICE FOR FLUID-PRESSURE BRAKES.

SPECIFICATION forming'part of Letters Patent No. 766,642, dated August 2, 1904.

Application filed January 2, 1904.

To aZZ whom, it may concern.-

Be it known that I, FREDERICK MnR'rsuEI- MER, of Denver, county of Denver, and State of Colorado, have invented a new and useful Improvement in Pressure-Retaining Devices for Fluid-Pressure Brakes, of which the following is a specification.

This invention has reference to the system of fiuid-pressure-operated brakes in which the brakes are actuated by brake-cylinders in controllable communication with auxiliary reservoirs charged through a train-pipe from a main source of fluid under pressure; and the invention has reference more particularly to the mechanism now commonly used in connection with systems of this type for retaining a working pressure in the brake-cylinder after it has been operated to apply brakes, to the end that the brake-cylinder will continue to be operative during the recharging of the auxiliary reservoirs. In the operation of this system of brakes a definite pressure from the main source of supply is maintained throughout the train-pipe and auxiliary reservoirs, which pressure when the brakes are to be applied is relieved, and this action, through the medium of a triple valve situated in the communication between the auxiliary reservoirs and the brake-cylinder, will admit pressure to the brake-cylinder from the auxiliary reservoir, and this pressure acting on the brake-piston will apply the brakes. hen the brakes are to be released, the previous pressure in the train-pipe is reestablished, which action will by means of the triple valve open communication of the brake-cylinder with the atmosphere and simultaneously recharge the a-uxiliary reservoir.

The mechanism for retaining a working pressure in the brake-cylinder while the auxiliary reservoir is being recharged is usually in the form of a valve applied in such manner as to control the exhaust of pressure from the brake-cylinder, which valve is of such form and construction that it will permit the escape of the fluid from the brake-cylinder only when at a certain predetermined pressure, usually fifteen pounds, the result being that the valve will retain this pressure in the brake-cylinder under all conditions, so that Serial No. 187,517. (No model.)

while the auxiliary reservoir is being recharged this retained pressure is available for actuating the brakes for retarding the acceleration of the train.

It has been found in practice that under certain conditionsfor instance, light unloaded cars on a uniform moderate d0wngrade a retaining-valve formed to retain apressure of fifteen pounds is sutficient; but there are conditions encountered which demand a much higher retained pressure such, for instance, as heavily-loaded cars on mountain grades. It is not feasible to employ a single retainingvalve to meet both conditions, for the pressure retained would be such that under the conditions first named the friction of the brakes on the wheels would be too great and such as to cause sliding or skidding. It is necessary, therefore, that there be available two different retained pressures; and my invention consists, therefore, in combining with a mechanism for retaining a predetermined pressure in the brake-cylinder a device for retaining a greater pressure and suitable connections whereby one or the other of said devices may be brought into action at will.

In the accompanying drawings, Figure 1 is a bottom plan view of a car equipped with an air-brake system and showing how my invention is applied thereto. Fig. 2 is an end elevation of the same as viewed in the direction of the arrow in Fig. 1, showing my improved pressure-retaining device and its connection with the system. Fig.- 3 is a vertical longitudinal sectional view, on an enlarged scale, of the pressure-retaining devices shown in Fig. 2.

Referring to the drawings, and particularly to Fig. 1, 1 represents a train-pipe extending throughout the length of the train. 2 represents an auxiliary reservoir, 3 a brakecylinder, and I atriple valve, which latter controls communication between the train-pipe and auxiliary reservoir, between the auxiliary reservoir and brake-cylinder, and between the brake-cylinder and external atmosphere, as through port 5. As is well understood by those skilled in the art, a definite pressure is maintained in the train-pipe and auxiliary reservoirs, which pressure on being reduced by the engineer by mechanism under his control acts, through the triple valve, to connect the auxiliary reservoir with the brake-cylinder and applies the brakes, which latter are 1 released by the reestablishment of the previous pressure in the train-pipe,which action opens the brake-cylinder to the external atmosphere and recharges the reservoir. In order to retain a working pressure in the brake-cylinder, it is usual to connect-With the exhaust-port on the triple valve,through the medium of a connecting-pipe 6, extended upward at the end of the car, a pressure-retaining valve 7 such as indicated in Fig. 3, the purpose being to retain a predetermined working pressure in the brake-cylinder, so that while the reservoirs are being recharged the brakes may still act to retard the acceleration of the train. As shown in Fig. 3, this pressure-retaining valve comprises a casing 8, open to the atmosphere through port 9 in the bottom of the casing, and having mounted therein a vertically-movable weighted valve 10, which controls a port 11 in the casing communicating with the exhaust of the triple valve through the pipe 6. This valve being weighted so as to retain a pressure, say, of fifteen pounds is only lifted to open communication with the atmosphere by a higher pressure from the brake-cylinder, so that when the pressure is reduced to this amount the weighted valve seats itself, closes communication with the outside, and retains the pressure in the brake-cylinder. When it is not desired to retain a pressure in the brakecylinder, the valve is cut off from communication with the pipe 6 by a cook 12, applied in the pipe 6 and of such form that it may be turned to close communication between the pipe and valve and open the pipe to the atmosphere through port 13.

The foregoing parts may be of the usual and ordinary construction, and except in so far as hereinafter indicated and as combined with my improved device they form nopart of the present invention.

In carrying out my invention I provide a high-pressure device 1 1 of a form and construction which will retain in the brake-cylinder a greater pressure than that retained by the valve 7, and I so apply this device that one or the other may be used, as desired. This high-pressure device comprises a valvecasing 15, within which is'a chamber 16, open to the atmosphere, as at 17, and connected by port 18 through the bottom of the casing with a branch pipe 19, connected in turn with the pipe 6.

Port 18 is formed at its upper end with a valve-seat 20, against which is adapted to close a valve 21 on the bottom of a vertically-movable weight 22, mounted in chamber 16, the construction being such that fluid under pressure in pipe 19 will lift the weight and open the valve, and thus establish communication with the atmosphere only when said pressure exceeds that exerted by the weight. The relation of the weight 22 to that of the weighted valve 10 is such that the former will act to retain a higher pressure in the brake-cylinder, so that for conditions where the low-pressure retaining-valve is not suitable the high-pressure valve may be employed. These relations of the valves may of course be varied to meet the conditions encountered.

In order that the high-pressure device may act to perform its functions without interference fromthe low-pressure valve, I provide in the pipe 6 at a point between the connection therewith of the branch pipe 19 and the low-pressure valve a cut-off 23, preferably in the form of a plug-Valve formed so that it may be turned to cut off communication of the pipe 6 with the low-pressure valve, under which conditions the exhaust from the brakecylinder will pass through the branch pipe 19 and acting on the high-pressure valve will find its escape only when it is great enough to open the high-pressure valve.

In the operation of the system equipped with my improved device when the conditions are such as to demand the retention only of a light working pressure in the brake-cylinder plug-valve 23 is opened, so as to allow the exhaust to pass to the low-pressure-retaining valve, which will act to retain a light working pressure in the brake-cylinder. The fact that the high-pressure Valve is also and at all times in communication with the exhaust of the brake-cylinder will not affect the operation of the low-pressure valve, for the reason that it operates only at a high pressure. When, on the other hand, the conditions are such as to demand the retention of the higher working pressure in the brake-cylinder, valve 23 is closed, so as to cut out the low-pressure valve, under which conditions the exhaust can only find its escape through the high-pressure valve when its pressure is such as to operate said valve, and consequently a higher pressure will be retained in the brake-cylinder.

hen it is not desired to employ either of said pressure-retaining devices, cut-off cook 12 is turned to close communication between the pipe 6 and the low-pressure valve and open said pipe to the atmosphere through port 13. In this position of the parts the exhaust will pass to the atmosphere and will not be obstructed by either of the retainingvalves.

Having thus described my invention, what I claim is 1. In adevice of the class described the combination with a brake-cylinder of means for supplying fluid under pressure thereto, a pair of pressure-valves in normal communication with the cylinder and operable independently by difierent pressures in the latter and means for closing communication between the low-pressure valve and cylinder at will.

2. Inadevice of the class described the combination with a brake-cylinder, of means for IIO said valves being in normal communication with and independently operable by different pressures in the cylinder, and a cut-off valve in the exhaust-duct at a point beyond the branch duct for closing communication between the low-pressure valve and cylinder at will.

In testimony whereof I hereunto set my hand, this 10th day of December, 1903, in the presence of two attesting witnesses.

FREDERICK MERTSHEIMER.

WVitnesses:

WV. B. DUNLEVY, H. A. MAHAN.