Pressure-Responsive Device, e.g. for a Pneumatic Tyre

摘要

1,176,945. Tyre pressure indicator. A. MIRSKY. 14 Sept., 1967 [15 Sept., 1966; 20 Jan., 1967; 7 Feb., 1967], Nos. 41334/66, 40690/67 and 5691/67. Divided out of 1,176,946. Addition to 1,129,021. Heading B7C. A device for monitoring the pressure in a rotating pneumatic tyre is provided with an electrical circuit for generating a signal according to the pressure in the tyre and a centrifugal switch arrangement which opens the circuit when the tyre is stationary and closes the circuit when the tyre rotates at a speed above a predetermined value, the switch assembly including at least two liquid conductors, e.g. mercury, switches, which are spaced from the axis of rotation of the tyre and connected in series with the electrical circuit so that when the tyre rotates at a speed above the predetermined value, all the liquid conductor switches are closed. Fig. 1 shows a device for use with dual mounted tyres. The device comprises a casing 1, which is mounted on the wheel hub and which has two inlets 6 and two outlets 7, each inlet comprising two tyre valves 9, 10 and a spacing sleeve 11 provided with slots (not shown). Valve 9 controls the entry of air from inlet 6 to a tyre via the slots, tube 13, and outlet 7 and when sufficiently depressed operates valve 10 so as to connect tube 13 and bore 14. Bellows 16, 17 separated by a disc 18 are located between bores 14, 15 in the inlet and outlet respectively to provide a pressure-reference chamber 19 and tyre pressure-sensitive chamber 20. Disc 18, see Fig. 3, is provided with an extension 21 which is movable between contacts 22, 23. On inflating a tyre by supplying air via inlet 6 and outlet 7, valve 10 is opened and the pressures in chambers 19, 20 are equilibrated with that in the tyre. When inflation is stopped, valves 9, 10 close. If, in use, the tyre pressure alters, the pressure in chamber 20 will alter correspondingly and will move disc 18 and hence extension 21 towards one of the contacts 22, 23 of the extension touches one of the contacts, see Fig. 5, a circuit is energized to generate a signal which is transmitted to a receiver. The circuit shows terminals 25 for a radio transmitter and terminals 26 for a battery and a reed switch 29 for testing purposes.