Patent GB-252333-A (GB)
Title: Improvement in brake mechanism for automotive vehicles
IPC: B60T13/24
Filed: 1926-04-12
Abstract: 252,333. Bragg, C. S., and Kliesrath, V. W. May 19, 1925, [Convention date]. Fluid-pressure.-Fluid-pressure brake mechanism, particularly for heavy motor-vehicles and trailers, comprises a main actuator cylinder and double-acting piston with a controlling and reversing valve mechanism preferably within the piston, and one or more auxiliary actuator cylinders and pistons without valves and so connected to the main actuator as to be, simultaneouslv controlled by the, reversing valve mechanism thereof. The valve mechanism is connected with the piston of the main actuators by means permitting lost motion to allow the brakes to be directly operated. In Fig. 2, the, valve mechanism 10 is embodied in the double-acting piston .3 of a main actuator cylinder 1 as described in Specification 245,444 slidably mounted on the valve actuating sleeve 20 which passes through the piston rod 5. Operation of the pedal lever, which is connected to a lug 25 on the end of the sleeve 20, opens valves 41. 43 by collars on the sleeve. Communication is thus opened from the suction pipe of the vehicle engine through a pipe 62, part of the sleeve 20, apertures 24. suction chamber 17, past valve 41. and through a port 34 to one side of the piston. The other side of the piston is put into communication with the atmosphere, through an aperture 29 in the piston rod, part of the hollow sleeve 20, apertures 27 past valve 43, and through a port 36 to the other side of the piston. Brakes connected to a plug 28 screwed in the end of the, piston rod are thus applied. The ends of the cylinder 1 are connected by pipes 55, 56 to the corresponding ends of one or more actuator cylinders 51 which apply further brakes. When the movement of the foot lever and sleeve 20 stops, the piston con. tinues to move forwards till the. valves 41, 43 close, and the piston is held in balanced position. On release of the foot lever, valves 40, 42 are opened by the sleeve 20, thus reversing the connections of the suction pipe and the atmosphere to opposite ends of the cylinders 1, 51, a passage 19 providing communication with the atmosphere. and the pistons are returned to " off " position. A partial vacuum is maintained in these cylinders on both sides of the pistons, when the brakes are released, bv means of a. pipe 42f from the, suction pipe of the vehicle engine and pipes 42<a> 42<g> controlled by a valve 42<c> opened by a pin 42<e> struck by the piston when in retracted position. The lost-motion connection between the valve sleeve 20 and the piston rod consists of a collar 26 on the valve sleeve located in a, recess in the piston rod. The foot lever may have a lostmotion connection, bv means of slotted links, to the brake mechanism operated by the auxiliary cylinder 51. The valve casing may be connected to certain of the brake mechanisms by a lostmotion connection and be retracted by a spring against a stop so that it does not ordinarily move with the brake mechanism but the brakes may be operated directly. An adjustable restricting valve, a check valve, and an outwardly-opening vent valve on the. check valve are provided in the pipe connecting the suction pipe of the vehicle engine with the valve. actuating sleeve to prevent interference with the operation of the engine. Brakes for a trailer are operated by an auxiliary cylinder mounted on the trailer and connected to the main cylinder by pipes having flexible portions. A modified auxiliary actuation cylinder contains two opposed pistons operating different brake mechanisms. In an arangement for a sixwheeled vehicle, Fig. 4, the piston rod 305 extends through the opposite end of the cylinder to that shown in Fig 2 and is connected to the brake mechanism by a sleeve 377a enclosing the link connecting the pedal lever 388 and the valve actuating sleeve 320. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the subject-matter of Specifications 262,448. 262,449, and 262,450. This subject-matter does not appear in the Specification as accepted.