| 摘要 |
1,241,689. Anti-skid systems. TELDIX G.m.b.H. 25 Oct., 1968 [28 Oct., 1967], No. 50715/68. Heading F2F. [Also in Division H1] In a vehicle anti-skid system the REDUCTION in brake pressure is DELAYED for a period after the wheel - deceleration - signal reaches the limit-value, to prevent response to momentory oscillations of the signal. The delay period may be fixed e.g. by a timer or depend on the time signal takes to change by a predetermined amount. SIMPLE TIMER ARRANGEMENT, Figs. 3 and 4. Brake system.-Pressure transmitted to brake cylinder connection 7 by pedal 2 may be controlled by normally open "magnet-valve" E and normally closed magnet-valve A. (Valve E is by-passed by a constriction 10 to allow a slow rise in pressure when it is closed). Control circuit.-When deceleration switch closes at limit G1, Fig. 4, magnet-valve E is energized through diode 19 to shut-off and hold brake pressure (subject to slight rise through constriction 10). After a delay T, timer 17 operates to energize valve A and release brake pressure. The wheel thereupon speeds up and switch V opens to de-energize valve A and hold the reduced pressure. Valve E is maintained closed by capacitor 22 (through diode 21) for a short time t 12 -t 13 until switch B closes in response to acceleration of the wheel towards road-speed. In subsequent braking during momentary oscillations of the wheel (or switch device) at times t 15 -t 18 the pressure is held by valve E but timer 17 prevents pressure release by valve A. A DECELERATION SWITCH. A rotary inertia switch with a clockwork time-lag operative in the deceleration direction is described with reference to Figs. 9 ... 13 (not shown) see Division H1. This switch has two deceleration contacts V 1 , V 2 operating at different levels of deceleration and a "momentary contact" acceleration switch B which is open above and below a set value, and is used in a circuit Fig. 14 (not shown) comprising a slight modification of Fig. 3. ELECTRIC TIME DELAY, Fig. 5. The rate of change of speed signal U b is gated to an integrator and comparator 28 while it is negative (deceleration) and exceeds a limiting value determined by amplifier 26. After a time when the integral of the deceleration signal U b exceeds a reference value F, an output k is applied through flip-flop 30 to the pressure reducing valve A. The inlet valve E is closed through OR gate 29 by either the acceleration or deceleration signals in excess of the limits determined by amplifiers 25, 26. ALTERNATIVE ELECTRIC DELAY, Fig. 7. Utilizes speed and deceleration signals and depends on the time for the speed signal to change by a predetermined amount. The speed signal U v is initially fed to capacitor 39. When the deceleration signal U b exceeds the limit determined by amplifier 44 signal N from OR gate 36 (closes inlet valve E) and throws switch 35 so that the instantaneous speed signal U v is compared with the value stored in capacitor 39. When the difference exceeds the reference value 40, an output 1 to AND gate 42, together with the deceleration signal opens pressure reducing valve A. |
