| 摘要 |
752,747. Fluid-pressure servo-brakes. BENDIX AVIATION CORPORATION. Oct. 13, 1954 [Nov. 12, 1953], No. 29530/54. Class 103 (1). A spring-loaded valve member 92 is fitted at the outlet from the slave cylinder of a vacuum servo booster unit for hydraulic brakes which is such that in combination with the pressure needed to expand the brake shoes 28 against spring 29, it requires, to open it, a pressure in the slave cylinder 22, which will be in excess of that necessary to cause operation of the relay valve 65 controlling movement of the servopiston 18. This ensures that a substantial volume of liquid is not displaced from the master cylinder 57 past the slave piston 34 direct to the brakes before the servo-piston comes into effect, under which circumstances the master cylinder piston 55 might bottom and become ineffective for emergency direct operation. As shown in Fig. 2, the passage of fluid through the slave piston 34 is controlled by a ball valve 48 and seat 51, the substantial equalization of pressure on each side of the piston caused by the valve member 92 resulting in the ball 48 being urged away from its seat by the spring 49. A lightly loaded valve member 96 beyond the valve 92 provides for compensating fluid to the brake motor cylinders direct from the master cylinder reservoir. A modified form of slave piston having only a single passage therethrough is also described. Specification 620,593 is referred to. |
