| 摘要 |
1,105,351. Brake cylinders. SOC. ANON. D.B.A. 2 Feb., 1966 [5 Feb., 1965; 31 Aug., 1965], No. 4608/66. Heading F2F. An hydraulic control for the master-cylinder 12 of a brake system has a servo-motor 10 in which the movements of its piston 44 are effected by pressure in a chamber 70 which is controlled by a servo-valve spool 58 disposed in a chamber 42 between an opening 52 to an accumulator 54 and one 56 to a reservoir (not shown), the displacements of the spool 58 being actuated by a lever 74 pivoted on the casting 14 at 78 and operating on the piston 44 and the spool 58 through a feeler member 76 which is tiltable about an axis 86 carried on the lever 74 so as to move with it when it is tilted by movement of a rod 84 of given cross-sectional area where it extends into the control chamber and is adapted to abut the piston 44 in case of a failure in the control pressure. The lever 74 is in the form of a U which is pivoted through both its legs at 78 and is slit transversely at 80 to receive an axis pin 82 which passes through the push-rod 84. When the rod 84 is pushed into the chamber 70 the lever 74 carries the pivot 86 of the member 76 forward so that its surfaces 94 and 96 are urged against the piston 44 and the spool 58. The spring 48 of the former is stronger than the spring 62 of the latter so that the spool moves into its cylinder 42, first covering the reservoir outlet 56 and then uncovering the accumulator outlet 52 from which pressure fluid then passes through channels 66 in the spool and over its reduced diameter end 68 into the chamber 70. The pressure in the chamber 70 then drives the piston 44 against its spring 48 to actuate the piston 20 of the master cylinder 12 through the push-rod 50. At the same time the pressure presses back on the push-rod 84 providing "feel" to the operator. Fig. 3 (not shown), illustrates another embodiment in which modifications are made to a number of the components to simplify manufacture and assembly. |
