Abstract: The main tool housing of a multi-purpose tool is provided with an adapter that is adapted for coupling with a tire air valve, a finger piece disposed in the adapter and adapted to open the tire air valve, and an air inlet formed in the finger piece to permit entry of air into the main tool housing. A tire tread depth measuring unit includes a measuring rod that extends movably into the main tool housing, and a position sensor for generating an electrical displacement signal corresponding to length of the measuring rod that is extended out of the main tool housing when the measuring rod is used to measure depth of a tire tread. A tire pressure measuring unit includes a pressure sensor disposed in the main tool housing adjacent to the finger piece. The pressure sensor generates an electrical pressure signal corresponding to pressure of the air that enters into the main tool housing via the air inlet.

Abstract: A tire pressure gage consisting of a detecting head, a cylindrical casing, an inner tube, and a pressure measuring scale, a pressure setting scale, an inner tube locating cap, a fine adjustment screw, a pressure spring, and a bottom cap, wherein the spring force of the pressure spring can be adjusted by the fine adjustment screw so that the pressure measuring scale can accurately indicate the tire pressure; the pressure setting scale can be set subject to the desired tire pressure so that the T-shaped piston can automatically open the longitudinal center through hole of the pressure measuring scale for permitting excessive tire pressure to be drawn away.

Abstract: A tire pressure gauge comprises an outer housing seat provided with a semicircular slot having one open end provided with a ring-shaped edge and having another open end provided with a semicircular arresting edge. A first outer housing cover is used to fix a guide tube. The outer housing seat is provided with a battery compartment and a lamp socket extending from the periphery of the battery compartment toward the outer edge of the outer housing seat. A second outer housing cover is used to fix the batteries and the lighting fixture. The guide tube is provided at the front end thereof with a partition having a protruded column extending outwards from the center thereof. The protruded column is provided in one side thereof with an air hole. Disposed sequentially behind the partition in the guide tube are a piston, a pressure scale, a spring and a plug having a through hole dimensioned to permit the pressure scale to extend therethrough.

Abstract: A digital tire pressure gauge comprises a pressure measuring head to introduce thereinto the tire air. The pressure measuring head extends axially to form a tubular body in which a pressure bearing rod encased by a coil spring is received. The pressure bearing rod is coupled with a pressure converting unit serving to convert the displacement distance of pressure bearing rod into an electronic signal. A pressure displaying unit is connected with the output terminal of the pressure converting unit so as to exhibit thereon in digital form the electronic signal transmitted from the pressure converting unit.

Abstract: An air pressure measuring pen of a neat and satisfactory design is provided. The pen includes a transparent hollow pen tube having a top end and a bottom end, a clipping cover connected to the top end and having an exhaust valve, a check valve and a measuring head, a spring urging in the pen tube apart a stopping medium and a piston in the pen tube, an ink holder, and an ink holder positioner connected to the bottom end.