Abstract: A pressure gauge utilizing pressure sensitive liquid crystals. Several embodiments are disclosed of a liquid crystal tire pressure gauge associated with a valve stem of a tire. A pressure chamber in the gauge is provided with access to the tire pressure, and includes a transparent window for allowing viewing therethrough. A liquid crystalline material is mounted within the window, and is subjected to the pressure being measured such that it is responsive to different pressures to provide different visual appearances, thereby providing a reading of the pressure. In different embodiments, the pressure chamber is constructed as an integral part of the valve stem, or alternatively the pressure chamber is constructed as an integral part of an attachment cap which mounts on the valve stem.

Abstract: A dual valve assembly having a charge and relief valve, comprising a unitary valve structure including a thick central body section and, extending therefrom, a pair of elongated hollow cylindrical valve members. A valve core is threaded into the bore of each valve member and a conventional valve cap is screwed onto the free end of one member, which end is adapted to be connected to an air source. A spring-biased plunger-cap or assembly is threaded onto the free end of the other valve member, the plunger being operable to engage the pin of the valve core at that end so as selectively to relieve the pressure. A passageway in the central section communicates with both of the bores and by a hose connection, with a pneumatic device whose operation is to be controlled.