| 摘要 |
1,194,097. Fluid pressure control of brakes. ABEX CORP. 13 Nov., 1968 [14 Nov.. 1967], No.53946/68. Headings F2E and F2F. In an hydraulic system with a double-acting piston a flow-control valve links the head and rod ends of the cylinder to permit rapid advance of the piston (due to differential piston area). The system is stated to be applicable to e.g. a power press or railway vehicle brakes. As shown in a BRAKE SYSTEM, Fig. 2, pump P supplies the cylinder through highpressure line H1 and low-pressure line H2; with the brakes off L.P. line H2 applies e.g. 180 p.s.i. to retract the piston and line H1 drains at about 30 p.s.i. to tank via relief valve 35 (detailed in Fig. 3, not shown). To actuate the brakes, magnet valve 40 (detailed in Fig. 4, not shown) is energized to close the drain via line H4 so that pressure builds up in line H3 to close relief valve 35. When pressure in lines H1, H6 reaches say 175 p.s.i. the piston in valve 44 (detailed in Fig. 6, not shown) opens the valve to connect lines H1, H2 and piston 43 rapidly applies the brake. As pressure continues to rise low pressure relief valve 36 opens at say 200 p.s.i. allowing valve 44 to close. AUTOMATIC TRAIN BRAKE CONTROL SYSTEM, Fig. 7.-The vent valve 40 has variable energization in this case and acts as a variable constriction to vary the pressure in H1 correspondingly. As shown the actual braking torque is measured by a transducer attached to a link connected to the brake shoe, the amplified braking-torque signal Q is compared with the required braking signal P in a summation network S, and the error signal P<SP>1</SP> is applied to the magnet valve. The TORQUE TRANSDUCER may be a strain gauge or semi-conductor load-cell, or a differential transformer (detailed in Fig. 1B, not shown) mounted between a blade-spring (19) and a link (17) connected to the brake shoe. |
