Patent GB-309542-A (GB)
Title: Improvement in brake system for automotive vehicles
IPC: B60T13/24
Filed: 1929-04-03
Abstract: 309,542. Bragg, C. S., and Kliesrath, V. W. April 12, 1928, [Convention date]. Fluid-pressure. - In fluid - pressure brake mechanism for motor vehicles having a brake cylinder controlled by a plurality of separate valve mechanisms, an independent manuallyoperated lever is connected with each valve so that one lever is capable of applying all the brakes and the other lever only certain brakes of a vehicle. In Fig. 1, a brake cylinder 1 is controlled by valve mechanism arranged in the piston hub and operated by a hand lever 47 and also by a valve mechanism 6 operated by a foot lever 81. The cylinder 1 in front of the piston is connected permanently to the vacuum in the suction pipe of the vehicle engine by means of a pipe 65 and the rear of the piston is normally connected to this vacuum past the inlet valve in the piston hub, the interior of the control rod 42, a pipe 66, valve 6 and pipe 65<a>. The valve 6 is adapted on brake operation to bring the diaphragm 8, Fig. 3, against a seat 11 to close the vacuum pipe 65<a> and to open the pipe 66 leading to the actuator to air inlets 18, 18a by the withdrawal of the disc valve 10 from the diaphragm, thus admitting air to the rear of the actuation piston and operating the brakes B, Fig. 1. A slotted link 46<a> is provided in the hand lever connection to the valve rod 42 to allow the actuator piston to move on operation of the valve 6. The casing of the valve 6 is connected by a rod 83 to a transmission brake B<1> so that this is also operated by the foot pedal. Operation of the hand lever closes the vacuum valve in the piston hub and opens the air valve to bring about brake operation. The consequent movement of the piston reclosing the air valve to maintain the brake applied at the desired pressure. The usual lost-motion connection between the control rod 42 and the piston rod allows of direct manual operation. The connection 83 from the valve 1 may alternatively be connected to exterior brake mechanisms on the drums of the brakes B. In a modified form the foot pedal is adapted to operate the valve mechanism in the piston hub of a secondary brake cylinder adapted to operate the brakes on a further pair of wheels on a six-wheeled vehicle. In this case the pipe 66 from the primary cylinder is normally connected to suction through the secondary actuator in rear of the piston, past the vacuum valve in the piston hub, to the front of the secondary piston and by a pipe to the suction pipe 65. Operation of the foot pedal closes this vacuum valve and opens the air valve which admits atmospheric air through the valve control rod, to both the primary and secondary cylinders in rear of the pistons operating both sets of brakes. The foot pedal may also operate directly the brakes of the secondary cylinder. In a further modification, both cylinders are controlled by valve mechanism exterior thereto, and the pistons are normally submerged in atmospheric air. The cylinders are single acting and are connected to vacuum to operate the brakes. The exterior valve mechanism may be connected with further brake cylinders so as to control them. In a further modification, the exterior valve mechanisms are connected in direct linkages between the control levers and the brakes, and both control a single cylinder connected to one set of brakes.