Patent GB-260965-A (GB)
Title: Improvement in power actuator
IPC: B60T13/24
Filed: 1926-10-05
Abstract: 260,965. Bragg, C. S., and Kliesrath, V. W. Nov. 5, 1925, [Convention date]. Fluid-pressure.-A power actuator for vehicle brakes, steering-mechanism of automatic vehicles. and water or air craft, &c. comprises in combination a main actuator including a cylinder 1, Fig. 2, a double-acting piston 3 therein, and reversing valve mechanism 40 - - 4.3, Fig. 4. and connections therefrom to a source of suction.. such as the intake manifold of an internal-combustion engine, and a source of higher pressure fluid, such as the air, for establishing differences. of pressure on opposite faces of the piston, the valve mechanism being constructed to hold the piston in a balanced condition in an intermediate position of the valve mechanism, an auxiliary actuator including a cylinder 101. Fig. 3, and a piston 103 therein, the portion of the cylinder to the left of the piston being connected by a pipe 107 to the corresponding portion of the cylinder 1 and that on the right of the piston having an outlet passage 108 independent of valve mechanism to the source of suction, whereby higher pressure fluid may be admitted to both cylinders to effect the power stroke and withdrawn from both cylinders, and admitted to the cylinder 1 only to effect the return stroke, and means, such as a spring 71, for effecting the return stroke of the piston 103 without admission of air to the cylinder 101. The, piston 3 has a hollow boss 10 with chambers 11. 12, 17 and hollow rods 4, 5 passing through stuffing-boxes in the cylinder heads 2. The valves 40 - - 43 are mounted in pairs, between operating collars 40a -- 43<a>, on a sleeve 20 slidable, in the piston rods and provided with resilient means 50 between each pair of valves which co-operate with conical seats in the chambers 11, 12. The sleeve 20, which is plugged at 22. is connected to the suction intake manifold by a pipe 62 containing check and regulation valves to admit air gradually to the engine and prevent stalling, and the sleeve is also connected at 23 to a foot pedal with a spring for retracting it against a stop, in which position the valves are in the intermediate position shown in Fig. 4 and the piston 3 is balanced. Movement of the sleeve 20 to the right causes the valves 40, 41 to open and close respectively and air is admitted through the end 4a of the rod 4, the chambers 11, and a port 34 to the left of the piston 3 and through the pipe 107 to the left of the piston 103 to effect the power stroke, the piston 3 following up the valves to close the valve 40. By a slight relaxation of pressure on the pedal, the valve. 41 may be opened to relieve the brakes momentarily if desired. The effort of the operation may be added to the power of the actuator by causing the sleeve 20 to abut against the wall 6a of a cap on the piston rod 5. When the pedal is released, the sleeve 20 is returned to the left and causes the valves 41, 43 to open and the valve 42 to close, so that air is withdrawn from the portions of the cylinders 1, 101 to the left of the pistons and air is admitted to the right of the piston 3 through ports 5a in the rod 5, ports 22a in the sleeve 20, and the port 35 in the hub 10 to effect the return stroke of the piston 3, but no air is admitted to the right of the piston 109 which is returned to its initial position by the spring 71 confined between a cap 70 on the rod 104 and the head 102. Alternatively, the piston 103 may be returned by the load on the brakes &c. operated by the actuator. The air to the left of the piston 3 is withdrawn through the port 34, past the valve 42, and through ports 21 and the sleeve 20 to the pipe 62 and the air from the cylinder 101 through the pipe 107. and this air is gradually admitted to the suction intake manifold together with the air from the right of the piston 3 as this air can pass the partially open valves 42, 41 when the foot pedal is held against its stop. Both actuators may be mounted on one vehicle &c. to actuate the same or different brakes &c., or the auxiliary actuator may be mounted on a trailer vehicle to actuate its brakes - flexible connections being interposed in the pipes 107, 108. The piston rods 5, 105 may operate the brakes &c. through any desired means, but as shown, hydraulic transmission means is employed comprising cylinders 201 screwed on to the actuator cylinder heads, pistons 203 connected to the actuator piston rods, pipes 210 leading to hydraulic cylinders with pistons for operating the brakes, oil reservoirs 214 with passages 215, containing check valves 216, to the cylinders 201, vents 217 for occluded air. and breathing holes 218 which also enable air to pass through the ports 5<a> of the rod 5.