US651602A - Brake mechanism for electric-railway cars. - Google Patents

Description

Patented Luna I2, 1900. ,F. W. GARRETT.

BRAKE MECHANISM FOR ELECTRIC RAILWAY G'ARS.

(Application filed Sept. 16, 1899.

(No Model.)

/ WITNESSES:

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FRANK lV. GARRETT, OF JOHNSTOWN, PENNSYLVANIA, ASSIGNOR TO THE LORAIN STEEL COMPANY, OF PENNSYLVANIA.

BRAKE MECHANISM FOR ELECTRIC-RAlLWAY CARS.

SPECIFICATION forming part of Letters Patent No. 651,602, dated June 1 2, 1900.

Application filed September 16,1899-- $erial No. 730,696. (No model.)

To call whom it may concern.-

Be it known that I, FRANK W. GARRETT, of Johnstown, in the county of Cambria and State of Pennsylvania, have invented a new 5 and useful Improvement in Brake Mechanism for Electric-Railway Cars, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specifica- IO tion.

. My invention has relation to brake mechanism for electric-railway cars, and more particularly to electric brakes of that class wherein the braking action is effected by causing I 5 the motors to act as generators driven by the momentum of the car, the mechanical energy consumed in this manner resulting in the retardation and checking of the speed of the car. It is well known that electrical brakes of this class cannot be Wholly relied upon to bring the car to a full stop, especially upon grades, for the reason that the action of the motor-generators necessarily decreases as the speed of the car becomes less andsoon reaches a point where it is insufficient to further check the movement of the car, particularly if the latter is on a slight downgrade, and upon an upgrade if the car is brought to a stop so far as its forward movement is con- 0 cerned it will run backward. In consequence of this fact it is necessary to bring into use the mechanical brake equipment of the car to supplement the action of the electrical brake and bring the car to a full stop. This 3 5 requires the operation of two separate and independent mechanismsand levers.

It is the object of my invention to so combine an electrical and a mechanical brake that both may be applied by the operation of a single operating lever or handle, or, in other words, to combine with the drum or switch which controls the electric brake a brakestaff and connection to the brake-beams orbrake-shoes of the car, together with means whereby the latter is not effectively operated until after the final position of the brake-controlling switch has been reached.

lVith this object in View my invention consists in thenovel construction and combination of parts, all as hereinafter described, and pointed out in the appended claims.

Referring to the accompanying drawings, Figure 1 is a side elevation of one form of electric brake-controlling switch wit-l1 combined mechanical brake-operating devices. Fig. 2 is a detail view showing the stop for the switch or controller-d rum. Fig. 3 is a detail view of the pawl-and-ratchetdevices which control the notch positions of the said drum, and Fig. A is a detail view showing in plan the controller-drum and brushes or contact-fingers.

The letter A designates the rotary drum of a brake-controlling switch, upon whose periphery are mounted a plurality of contacts a, designed to be engaged by contact-fingers or brushes B. The particular construction of this drum and the arrangement of its contacts form no part of my invention and need not be described in detail, it being sufficient to say that the operation of this switch effects a condition of the motor-circuit in which the motors may operate as generators and that it has several different positions in which the amount of resistance in such circuit is varied to control the action of the motor-generators.

O designates a vertical shaft upon which the said drum A is loosely mounted.

O designates the usual ratchet-plate at the top of the drum, and O the pawl by means of which the drum is held in its several positions.

v d d designate diametrically-opposite stop projections 011 the controller-drum which are designed to engage a fixed stop (Z on the inside of the controller-casing, and thereby limit the movement of the drum to a halfrevolution. The stops may, however, be arranged to permit a longer or a shorter movement, according .to the particular construction and contact arrangement of the drum.

For the purpose of connecting the drum to move with the shaft C between its stops cl d and upon the engagement of said stops with the fixed stop 61 to permit independent movement of the said shaft various mechanical devices of well-known character may be employed. Asimple means is that shown,wherein the ratchet-plate O is provided with a tooth c, which is designed to be engaged byatooth g, carried by a spring G, secured to the under side of aplate-collar G, which is fixed to the shaft 0. So long as the controller is free to move, the friction between the teeth 0 and g is snfiicient to lock the drum to the shaft. When, however, either of the stops d (1 engages the fixed stop d this friction ,is overcome, the tooth g slips over the tooth c, and the shaft C moves independently of the drum. This insures the latter being left in proper initial and final positions.

II is the operating-handle, which is rigidly secured to the upper end of the said shaft. The lower end portion of said shaft, which extends through the car platform or floor and is connected to a chain 1, leading to the brakerigging of the car, is preferably made in a separate piece and is con uected to the upper member of the shaft by a ratchet-and-pawl device K, which may be similar to that which is usually employed in brake-rigging forconnecting the handle to the brake-staff.

L designates the usual brake ratchet and pawl.

The operation of the device will be readily seen. To apply the brake, the handle II is turned to move the controller-drum through the usual series of steps which effect the desired changes in the motor-circuit to cause the motors to act as generators. 1f the car fails to come to a full stop on the last position of the controller-drum, the latter (by the stop devices described) is left on its last position, and the shaft 0 is further actuated in the manner of an ordinary brake-staff to apply the mechanical brakes. There is sufficient slack in the chain I, so that the brakeshoes do not set until after the controllerdrum has reached its last position.

It is obvious that my invention is much broader than the particular embodiment thereof and mechanical details which I have herein shown and described, and Ido not wish to be limited thereto.

Having thus described myinvention, hat I claim, and desire to protect by Letters Patent, is

1. The combination of a controller frame or casing, the drum therein, a rotary shaft upon which said drum is loosely mounted, a clutch device for connecting said drum and shaft, a notch plate and pawl for determining the working positions of the said drum, cooperating stops on said drum and easing arranged to come into operative en gagement to positively lock said drum at a certain point to each side of its range of operative positions, and a brakeactuating chain connected to the said shaft, substantially as described.

2. In brake apparatus of the character de-,

scribed, the combination of a brake-stall" or spindle, a brake controller drum loosely mounted on said shaft, a clutch connection between the drum and its shaft, and stop devices arranged to positively lock the drum at a certain point to each side of its range of 0perative positions and thereby cause the disengagement of said clutch connection, substantially as described.

In brake apparatus of the character described, the combination of a brake-staff or spindle, a controller-drum loosely mounted thereon, a spring-pawl carried by said staff or spindle, a notch-plate carried by the said drum and having a tooth or projection for engagement with the said pawl, and means for preventing the movement of said drum beyond a certain point in cither direction, substantially as described.

In testimony whereof I have affixed my signature in presence of two witnesses.

FRANK V. GARRETT.

Witnesses:

MYRTLE E. SI-IARPE, H. W. SMITH.

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