GB344580A - Improvements in brake system for automotive vehicles - Google Patents

Abstract

344,580. Vehicle brakes. BRAGG. C. S., Palm Beach, Florida, and KLIESRATH, V. W., Port Washington, New York, both in U.S.A. Jan. 2, 1930, No. 211. Convention date, March 28, 1929. [Class 103 (i). Fluid-pressure ; hand or foot actuation.-Brake apparatus for vehicles comprises main and auxiliary cylinders connected to different brakes and two valves adapted, the one to control all the cylinders and the other the auxiliary cylinders independently. The pistons are normally subject to vacuum on both sides, air being admitted to one side to apply the brakes. Separate pipe connections extend from the vacuum source to those piston chambers in which the vacuum is constantly maintained so that the fracture of one pipe does not put both cylinders out of action. Direct effort may be applied by the pedal or hand-lever of both valves to different brakes. Fig. 1 shows main and auxiliary cylinders 1, 101 connected to brakes on a tractor and trailer respectively. The main cylinder 1 comprises hollow piston-rods 5, 5a, Fig. 2, of which the part 5 is connected by link 78 and other connections shown to internal brakes B on the tractor wheels W. The chamber on one side of the piston 3 is connected by the pipe 26 to the suction pipe 61 of the engine of the vehicle. The main valve mechanism comprises a sleeve 20 connected to a pedal 88 and having slidably mounted thereon between a pair of collars, suction and air valves 40, 41 urged apart by a spring. A spring 15 interposed between collars on the sleeve 20 and rod 5a normally holds the valves 40, 41 respectively open and closed so that the rear piston chamber is connected to the forward chamber and thus to suction by the passage 35. A valve 6 prevents the admission of air through the piston-rod 5a. When the sleeve 20 is moved forwardly by the pedal 88 the valves 40 and 41 are respectively closed and opened thereby admitting air through the passage 10 and the piston-rod to the rear piston chamber to apply the brakes. If the pedal is held the continued movement of the piston 3 effects the closure of the valve 41 and the braking pressure may thus be graduated. By the engagement of collars 24, 25 on the valve sleeve 20 and piston-rod 5, the operator may apply a direct effort to the same brakes B that are applied by the piston 3. The piston of the auxiliary cylinder 101 is connected to brakes B<2> on the trailer. The forward piston chamber of this cylinder is connected by pipe 126 to the engine suction pipe 61 and the rear chamber by pipe 127 to the valve V by which the cylinder is independently controlled. This valve comprises a casing 110, Fig. 4, connected to a hand-lever 188 and a pair of valves 140, 141 slidably mounted on a rod 120 between collars and urged apart by a spring. A pipe 27 extends from the rear chamber of the main cylinder 1 to the valve casing 110 and the valve 140 being normally open, the pressure conditions in the rear chamber of cylinder 101 correspond with those in that of the rear chamber of the cylinder 1 so that the tractor and trailer brakes B, B<2> are simultaneously controlled by the main valves 40, 41. The trailer brakes can be independently applied by operating the hand-lever 188 to move the casing 110 forwardly so as to close and open respectively the valves 140, 141 thus connecting the pipe 127 and rear chamber of the cylinder 101 to atmosphere through passage 114. The valve rod 120 is connected to external brakes on the tractor wheels W and the operator may thus apply a direct effort to these brakes by the hand-lever 188 by the engagement of the casing 110 with a collar 128 on the rod 120. Non-return valves 65, 165 prevent back-flow from the suction pipe 61 to the pipes 26, 126 and a non-return valve 126d is provided in the pipe 126 on the trailer so that the trailer brakes are applied if the trailer should break away. Additional cylinders may be connected to the cylinders 1, 101 by pipes p. An arrangement is also shown in which both the cylinders 1, 101 are provided on a six-wheeled vehicle, the cylinders being connected respectively to brakes on the forward and rearward pairs of rear wheels and the hand-lever 188 being arranged to apply a direct effort to separate brakes on the forward pair of rear wheels.