Temperature and pressure compensating indicator

摘要

A tire pressure gauge apparatus for securing to a vehicle tire valve stem mounted to a tire valve stem port in a vehicle tire includes an apparatus housing containing a received air chamber for placement in fluid communication with received air from within a vehicle tire and containing a biasing air chamber containing a fixed quantity of biasing air, the chambers being sealingly separated from each other by a pressure equilibration structure which includes a pressure indicator element, the pressure equilibration structure moving within the housing to alter the relative volumes of the two chambers and thus to equalize the pressures of the two chambers, and the pressure indicator element moving relative to the apparatus housing as the equilibration structure moves to equalize chamber pressures to display a tire pressure reading.