Patent GB-252111-A (GB)
Title: Improvements in and relating to brake control mechanisms for power-propelled vehicles
IPC: B60T13/16
Filed: 1925-08-11
Abstract: 252,111. Staude, E. G. May 18, 1925, [Convention date]. Fluid-pressure.-Brake control mechanism for power-driven vehicles comprises a power-operated fluid pump in a circulating system controlled by a valve device which is normallv open and consists of a pair of co-axial rotary sleeve valves one of which is operable by a pedal, for closing ports in the valves to obstruct the flow in the system in order to build up pressure therein to operate the brake connection, the other valve being actuated in response to such pressure to open the ports and reduce, the pressure. The pump comprises gear wheels 10, 11, Figs. 6 and 7, the wheel 10 being mounted on the transmission shaft 12 so that the pump mav be driven by the motion of the vehicle when the motive power is inoperative or the clutch disengaged. Fluid normally circulates from the transmission gear casing 2 through the inlet port 19, channel 20, and chamber 21 and through apertures 22, 23 and a. passage 24 in the. valve device into a chamber 25 provided with an outlet 26 leading back to the casing 2. The, coaxial rotary sleeve valves 27, 30 are formed with radial slots 22. 23. The stem 34 of the valve. 27 carries an arm 28. Figs. 7 and 11, which is connected bv a rod 57 to an arm 56 on a brake lever 48 pivoted on the same axis 50 as the brake pedal 54. an arm 58 on which is connected by a rod 59 to an arm 31 on the stem of the other sleeve valve 30. The brake lever 48 connected to the brake by a rod 6, has a portion 51 extending behind the brake pedal and carrying an adjustable stop 52, a spring 55 being interposed between the brake pedal 54 and lever extension 51. When pressure is applied to the brake, pedal. lost motion between it and the extension 51 is taken up and at the same time the pedal operates through the rod 59 and arm 31 to rotate the inner valve 30 so as to obstruct the fluid in the circulating system. The fluid then flows around the valves and builds up pressure in a chamber 37, Figs. 7 and 14, which communicates with the brake cylinder 38, Fig 11, by the pipe 39. The piston 45 is then raised so that its rod bears against the brake lever 48 and applies the brake, but at the same time, the lever 48 operates through the rod 57 and arm 28 to rotate the outer valve 27 and bring the radial slots of the valves again into register and reduce the pressure. This cycle of movements is rapidly repeated, until the brake is fully applied. The pump gear wheel 11 is mounted on a spigot 17 at the end of the transmission gear casing 2, and the wheel 10 is mounted on a sleeve 13 retained on the transmission shaft 12 by the usual universal coupling member 7 and nut 16, the wheel, shaft, and sleeve being keyed together at 14. In order to use the usual sheet packing at the end of the pump casing, the casing is recessed to receive a plate 65 covering the gears, the packing 67 and cover plate 68 being .applied and secured in the usual manner. Excessive pressure in the chamber 21. Fig. 7, is released by a valve 41, the pressure being indicated by a gauge connected to the pipe 63, and the sleeve valves 27, 30 are formed with apertures 35, 36 to permit the escape of pressure fluid which mav leak past the valves. The brakes may be applied directly bv the. pedal in case of failure of the fluid-pressure system.