Patent GB-259980-A (GB)
Title: Brake operating mechanism
IPC: B60T13/24
Filed: 1926-10-14
Abstract: 259,980. Trail, H. H. Oct. 19, 1925, [Convention date]. Void [Published under Sect. 91 of the Acts]. Fluid-pressure.-A power actuator for the brakes of motor vehicles and operated by suction from the intake manifold of the engine comprises a cylinder, a piston, a control rod slidable, in the cylinder end wall and having a longitudinal passage extending through it from end to end and communicating with the interior of the piston, and valve means arranged in a plane at right angles to the cylinder axis and co-operating with ports in the piston to control communication between the atmosphere, the cylinder space, and the passage in the control rod which is connected to the intake manifold. As shown in Fig 1. a piston 3 in a cylinder 1 has a hollow chamber 4 with ports 26, 27 to the cylinder space and the atmosphere respectively. A control rod 5 with a passage 6 communicating through a nipple 7 and a flexible tube 8 with a pipe leading to the intake manifold passes through a stuffing-box containing non-coherent packing 30 engaged by the concave face of a ring 31 which is forced towards the packing by a confined spring 32. The rod also passes through one wall of the chamber 4 and is acted upon by a spring 15 compressed between the chamber wall and a ring nut 16 on the rod. A disc valve 23 is urged by a light spring 25 towards the rod 5 and in the normal position shown closes the end of the passage 6. The left end of the rod 5 is connected to a pedal lever and when the rod is moved to the left, on operation of the pedal, the spring 15 is compressed and the valve 23 follows the rod until it seats on a seating 21 in the chamber 4 and cuts off the atmosphere from the cylinder space. Further movement of the rod opens communication between the passage 6 and the cylinder space through the port 26 and the piston is moved to the left and applies the brakes through a connection 18. A shoulder 14 on the rod 5 can abut against the wall of the chamber 4 to allow the operator to actuate the brakes directly by the pedal if required. A split ring 28 bedded in the cylinder wall acts as a stop for limiting outward movement of the piston, and a flexible guard 29 prevents entrance of dust &c. into the cylinder. In a modification, two disc valves 43. 44. Fig. 4, are mounted on the control rod 37 and are pressed by springs 47 towards a central boss 36 on the piston 35. The springs are confined by plates 41, 42 on the rod 37 and pins 45. 46 on these plates pass through holes in the boss and the adjacent valves. The passage 48 in the rod 37 communicates at its inner end with a port 49 in the boss, another port 52 passes through the boss. and a cap 51 screwed on the boss has a port 53 to atmosphere and provides means for connecting the piston to the brakes. Movement of the rod 37 to the left causes the pins 46 to lift the valve 43 from its seat and open the port 49 so that the passage 48 communicates with the cylinder space. Return movement of the rod is effected by a spring and causes the valve 43 to close and the pins 45 to lift the valve. 44, so that there is a free passage from atmosphere to the cylinder space.