Patent GB-345889-A (GB)
Title: Improvement in vacuum brake system for automotive vehicles
IPC: B60T13/24
Filed: 1930-06-05
Abstract: 345,889. Fluid - pressure brakes. BRAGG - KLIESRATH CORPORATION, 3901, Queens Boulevard, Long Island City, New York, U.S.A. June 5, 1930, No. 17452. Convention date, June 18, 1929. [Class 103 (i).] A vacuum brake for motor vehicles comprises a manually-operated valve controlling brake-cylinders, some of which have pistons submerged in vacuum and some have pistons submerged in fluid at atmospheric pressure when in the released position. Means such as restricting valves are provided to provide a more rapid braking action in some cylinders. One end of the vacuum cylinder is permanently connected to the vehicle engine induction pipe and the other end is controlled by the valves 40, 41 through a port 12 of the control valve. One end of the atmospheric cylinder is permanently connected to atmosphere and the other end is controlled by a diaphragm 23 and a disc valve 25 through a port 19. Ports 8, 18 are connected to the vehicle engine induction pipe. In brake release position shown the working end of the vacuum cylinder is connected to vacuum past the valve 40 and the working end of the atmospheric cylinder is connected to atmosphere past the disc valve 25 and through apertures 24, 15. A leaf spring 27 holds the parts in this position. Operation of the foot-pedal connected to the valve-rod 20 closes valve 40 and opens the port 12 to the atmospheric apertures 15 by means of the valve 41. Also the disc valve 25 closes on the diaphragm 23 which is moved from a seating 16 to open the port 19 to vacuum port 18. The valve casing is connected by a rod 80 to the brake mechanism, the movement of which recloses the valves when the foot-pedal is held stationary, the brakes can also be applied directly by the brake-pedal when a collar 24 engages the valve casing. The atmospheric cylinder is shown connected to the front wheel brakes and the vacuum cylinder to the rear wheel brakes of a motor vehicle. In a modification the vacuum cylinder operates the brakes on a trailer. In order to obtain a slower braking action on one cylinder than the other the cylinders or the supply pipes may be of different sizes or regulatable restricting valves may be provided in these pipes. Further cylinders may be controlled by the same valve by means of branch connections from the supply pipe having stop-cocks closed when these branches are out of use. A modified form of valve, Fig. 5, is connected to brakes not operated by the brake cylinders and there is no follow-up action although this action can be obtained with this valve. Valves 240, 241 control the atmospheric cylinder P<4> and valves 242, 243 control the vacuum cylinder P<5>. The chamber 207 between the valves 241, 242 is connected to vacuum through the hollow controlrod 220. When the brake is applied the valve 243 is opened to connect the vacuum cylinder to atmosphere through the ports 215 and the valve 241 connects the cylinder P<4> to vacuum. On release of the brakes the valve 240 connects the cylinder P<4> to atmosphere by means of a passage 206<x> and the ports 215 and the valve 242 connects the cylinder P<5> to vacuum.