GB1493587A - Tyre valve assembly - Google Patents

Abstract

1493587 Valves INDUSTRIE PIRELLI SpA 11 Dec 1974 [12 Dec 1973] 53640/74 Heading F2V [Also in Division B7] A tyre valve assembly for vehicles for enabling the relationship of the temperature or pressure within a tyre to a predetermined temperature or a predetermined pressure range to be monitored, comprises a valve stem 7, a support member 8 locating said stem and adapted for fitting to a wheel rim or tyre inner tube, and a sensor switch 5 subjected in use to the temperature or pressure within a tyre to which the assembly is fitted and operable to adopt a predetermined condition when the temperature or pressure within the tyre adopts a predetermined relationship with said predetermined temperature or said predetermined pressure range, said sensor switch being electrically connected through said valve stem with one terminal of an output and through its support member with a second terminal of the output for enabling the condition of the switch to be monitored externally of the tyre. As illustrated, a housing 4 containing a pressure responsive switch 5 is integral with, or screwed on to, a support member which is of synthetic plastics material, e.g. nylon. One contact of switch 5 is directly or indirectly (Fig. 2) connected to conductor 9, and the other contact is connected to a conductor which abuts an inflative valve stem 7 when the latter is forced into the support member 8. A conductive ring 18 links a wire 24 with conductor 9 and conductive ring 19 links wire 25 via nut 21 with the conductive stem 7. Conductor 9 may be a wire (not shown), a net of wires, a layer obtained by metal-plating on the outer surface of the support member, a metal strap or jacket embedded in the support member, or a layer obtained by metal plating the inner surface of the support member 8, the latter layer being insulated by rings from the stem 7. The support member and inner tube 3 may be bonded to a rubber collar (32) (Fig. 3, not shown) or for a tubeless tyre the rubber collar is in snap-in engagement with an aperture in the rim (Fig. 4, not shown). In operation, a pressure outside the predetermined range effects closure of a switch 5 (in an alternative arrangement the switch may be opened) thus causing a transmitter means (not shown) on the wheel to transmit a signal to a detector (not shown) on the vehicle chassis so as to actuate an alarm device connected to the detector.