| 摘要 |
1294212 Tyre deflation indicators ELTICO MFG Ltd 12 Aug 1970 [12 Aug 1969] 38921/70 Heading B7C [Also in Division G1] A tyre deflation detection device comprises an inductive sensor, means carried in the tyre for modifying the reactance of the inductive sensor upon a preselected amount of tyre deflation, and means responsive to the change of reactance for indicating said deflation. The inductive sensor S is secured to the wheel mounting to extend transversely of the tyre tread and comprises a wire loop of turns of wire 2 in a copper tubular ring 4 embedded in a plastics case 6, the loop being connected to the oscillatory part of a detecting and indicating circuit (Fig. 10, not shown). Within the tyre T, contacting the surface beneath the tread, is a plastics foam ring 8 having a flexible impervious skin 10 and containing ferromagnetic arcuate segments 12. When the tyre is inflated, as shown in Fig. 4, the ring 8 is collapsed against the tyre and the segments 12 lie within the magnetic field F associated with sensor S. On deflation the ring 8 expands moving the segments 12 away from the field F to modify the self inductance and hence reactance of the sensor, which causes a reduction in the amplitude of the oscillations and a lower output of a transistor (Q1) with the result that the output of the amplifier circuit is insufficient to energize a relay (R) and a lamp 24 and buzzer 22 of the indicating means are operated. One sensor can serve two adjacent pairs of twin wheels and a plurality of sensors can be connected to one circuit; alternatively an individual sensor, circuit and indicating means can be used for each tyre. When fitted to a tyre with an inner tube (14, Fig. 5) the ring 8 is positioned between the tube and the tyre cover and the skin 10 can be omitted. |
