Patent ID: 6009749
Filing Date: 2000-01-04
Classification: G01L

Abstract:
A tire pressure gauge comprising:a tubular housing having a first end portion and a second end portion formed with an axially extending elongated guide slot that extends from a distal end face thereof;a pressure measuring head connected to said first end portion of said tubular housing and having a pressure inlet hole communicated with said tubular housing:a piston mounted movably inside said tubular housing adjacent to said pressure inlet hole for longitudinal movement in response to a pressure introduced through said pressure inlet hole;an elongated plunger extending longitudinally in said tubular housing and having a driven end portion disposed adjacent to said piston so as to be driven by said piston, and an opposite guided end portion provided with a radial pin which projects radially therefrom and which is extendible outwardly of said tubular housing via said guide slot, said guided end portion of said plunger being formed with an axial bore;a hollow guide unit disposed in said second end portion of said tubular housing for guiding axial movement of said plunger relative to said tubular housing;a spring mounted inside said tubular housing around said plunger between said piston and said hollow guide unit for biasing said piston toward said pressure inlet hole; anda pen element inserted in said bore of said plunger and having a writing end which extends outwardly of said bore;said writing end being retracted into said tubular housing to a retracted position when said radial pin is moved in said guide slot toward said first end portion of said tubular housing, said writing end being exposed from said tubular housing to an exposed position when said radial pin is moved to extend out of said guide slot, said plunger being rotatable axially relative to said tubular housing to engage said radial pin with said distal end face of said second end portion of said tubular housing when said radial pin is extended out of said guide slot to maintain said writing end in the exposed position.