| 摘要 |
1,157,174. Fluid pressure brakes. GIRLING Ltd. 6 May, 1968 [23 May, 1967; 12 Oct., 1967], Nos. 23883/67 and 46582/67. Heading F2F. [Also in Division G1] Each of the wheels of a vehicle incorporates electric acceleration measuring apparatus whereby the brakes are released if the wheel decelerates too quickly, or locks. As shown, the wheel drives an alternator 11 to produce a signal voltage representative of speed, which is rectified at D2-D5, smoothed at R9, R10, C7, C3, C4 and differentiated at C2, R1, R2 to obtain an acceleration signal voltage which is fed to the base of transistor Q1. This transistor is normally conducting via resistors R1, R2 allowing the subsequent transistors Q2-Q5 also to conduct, the current flow through Q5 being insufficient to energize relay winding 21. Positive acceleration produces an additional positive signal at Q1 which does not affect the circuit conditions. Deceleration produces a negative signal at Q1 which reduces its conduction current and allows the conduction current of the other transistors to increase. At a predetermined deceleration, established by variable resistor 22, the current through Q5 energizes relay winding 21 to release the brakes. The circuitry ensures that the brakes are held released even if the wheel locks. The acceleration signal may alternatively be fed to the base of Q2, thereby energizing relay winding 21 at a predetermined acceleration to prevent further power being provided to the wheels. The system is tested by a switch 24, which, when closed and then opened, produces a nominal deceleration signal which should momentarily energize winding 21. Automatic temperature compensation is provided by thermistor 23 and resistor R11. The circuit is energized by a battery 19 which is continuously charged by the rectified speed signal voltage, or battery 19 is replaced by a capacitor charged by this voltage. |
