US762995A - Air-brake. - Google Patents

Description

No. 762,995. PATENTED JUNE 21-, 1904. J. H. GRAHAM & E. M. POTTS.,

N0 MODEL.

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PATENT OFFICE.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 762,995, dated June 21, 1904.

Application filed, May 11, 1908. Serial No. 156,583. (No model.)

To all whom it may concern.-

Be it known that we, J AMEs H. GRAHAM, and EDWARD M. Io'r'rs, citizens of the United States, and residents of'Seattle, King county, State of Washington, have invented a new and useful Improvement in Air-Brakes, of which the following is a specification.

This invention relates to mechanism' for operating the brake devices of railway-trains or street-cars by the use of compressed air or other fluids.

The object of the invention is to provide.

improved means for controlling the pressure of the actuating fluid, whereby the brake is applied or disengaged.

The several features of our invention and the advantages arising from their use, conjointly or otherwise, will be apparent. from the following description.

In the accompanying drawings, Figure 1 is a longitudinal sectional view of the brake devices embodying our invention, and Fig. 2 is a longitudinal sectional view of the pistonvalve shown in Fig. 1.

In said drawings the letter H represents the brake-cylinder, provided with a piston O, having a piston-rod I extending through a stuffing-box, such as Y, of which X is the gland and W its packing-nut. The cylinder is connected at its head end by a branch K with the train-pipe L. The end ofthe cylinder opposite its head is connected to a chamber, such as G, which chamber forms an air-reservoir. We prefer to make the said cylinder and reservoir integralthat is, of a single piece-and divide the same into the aforesaid parts by a partition, such as S, which strengthens the shell thereof and also furnishes a stop limiting the travel of the brake-piston, while hole M in partition S allows the free passage of the fluid between the reservoir and the brakecylinder.

To prevent leakage of fluid from one side of the piston to the other in the brake-cylinder and yet allow a relatively unconstrained movement of the piston, O is provided on its periphery with reversely-arranged L-shaped rings of leather or other suitable material (shown in drawings, but unlettered) and held in place by a follower, which is secured tothe spending seat of the valve-casing.

piston by bolts, as shown in drawings, but unlettered.

V represents an aperture for the reception of a key for securing the piston-rod to the cross-head, and the latter is connected to the brake-lever by a pin inserted through hole U provided.

Fig. 2 shows an enlarged longitudinal view of valve in piston O, of which C represents piston; A A, packing rings; B, spiral spring; D, bevel-face valve; E, valve-casing; F, nutholding valve D, and T T represent holes.

Inserted within an aperture provided in the piston O is the socket or casing E, having in one end'thereof a cylindrical or bored chamber terminating at a partition, which partition is situated equally distant from the ends of said casing. Piston C, provided with packingrings A A, is positioned within saidcylindrical chamber and has a stem or spindle extending through a registering hole provided in the partition and is connected integrally to a disk valve D, which is adapted to fit upon a corre- An advantageous way of connecting this valve to the stem is by the use of a screw-nut, such as F. i The cylinder end of the valve-casing projects interiorly of the brake-cylinder and communicative connection is made between the latter and the space between the valve D and the partition in casing E by the holes T T,

whereby it is evident that the air-pressure within the brake-cylinder and its piston will have a tendency to unseat the said valve by bearing against the same and against the exposed face ofthe valve-piston.

The valve is prevented from'opening, however, until the pressure within the brake-cylinder exceeds that of the reservoir to a predetermined amount.as, for instance, ten

.pounds per square inch-which result we attain by means of a spring, such as B, and by the normally unbalanced air-pressure and its sure of spring B. Then valve D is opened to admit the air'to the reservoir, which is charged therewith, so as to be under the same pressure as is exerted in the cylinder less the strength of said spring.

It is apparent that when the air is exhausted from the brake-cylinder side of the piston the compressed air of the reservoirwill force out the piston and apply the brakes. To disengage the brakes, the piston is moved rearwardly by readmitting compressed air into the cylinder at a pressure in excess of the ultimate or expansive pressure of the reservoir and overcoming the inertia of the brake parts and the opposing pressure within the reservoir.

By this invention it is obvious that springs are not required to force the piston back and release the brakes or the extra amount of Work required to overcome the springs when setting the brakes. Furthermore, the device is actuated from a line of train-pipe, which is connected to the cylinder end only of the apparatus, and hence the controlling apparatus, such as valves, are reduced to aminimum. It may be said that when for any cause the trainpipe should become broken or disconnected then the brakes would automatically be ap plied by the power of the compressed air contained within the reservoir and will so remain until the compressed air is withdrawn by a cock or bleeder, opening the reservoirshell.

Having described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In an air-brake apparatus, the combination with an air-reservoir, a cylinder making communicative connections with a train-pipe,

pressure within the reservoir relative to the cylinder-pressure, such means comprising a valve-socket having an intermediate partition, and provided with a side inlet communicatively connecting the compartment formed on one side of the partition with the cylinder, a disk valve and a piston positioned respectively upon each side of said partition and integrally connected by a valve-stem extendingthrough said partition, and a spring interposed between the said last-netned piston and the partition whereby the valve is normally retained upon its seat.

2. In an air-brake apparatus, the combination with an air-reservoir, a cylinder making communicative connections with a train-pipe, and a piston having a piston-rod projecting through the end of the cylinder, of the means arranged in. the said piston for regulating the pressure within the reservoir relative to the cylinder-pressure, such means comprising a valve-socket, havingan intermediate partition and provided with side inlet communicatively connecting the compartment formed on one side of the partition with the cylinder, a disk valve, and a spring adapted to'retain the said valve normally upon its seat.-

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

JAMES H. GRAHAM. EDWARD M. PO'ITS. Witnesses:

J Essn L. WALLER, FRANK B. SAYRE.

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