Dunlop Gmbh

Philip H Pegram

Samuel E Harvey

John A Stevens

The invention provides a deflation warning device for a pneumatic tire which gives a clear, positive indication of a predetermined pressure loss by the exposure of a brightly colored element within a transparent dome, all moving parts of the device being fully enclosed and protected against the ingress of dirt and corrosion by a housing. The element is either masked or unmasked by an opaque shield mounted on a piston which is biased by a spring to unmask the element but can be displaced by tire pressure acting on its surface to mask the element. In preferred embodiments of the invention the piston is located between the inner and outer parts of a second piston which is in turn responsive to tire pressure acting on its upper surface.

Pressure indicator for pneumatic tires

A thermal fuse device for deflating a pneumatic tire in the event of high temperature has an outlet for the molten eutectic plug which is separated from the air outlet so that venting air will not tend to re-solidfy the eutectic. The eutectic plug abuts a step or shoulder to prevent 'creep'.

Thermal fuse device

A device is provided which can be screwed onto the adaptor of the valve assembly of a pneumatic tire and a plunger depressed to commence tire deflation. A pressure sensitive member responds to a drop in the pressure of the emerging air to allow the valve to close when a predetermined low pressure remains in the tire.

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Leamington Spa, United Kingdom

Philip H Pegram