摘要 |
A circular indicator gauge includes a body of molded plastic and a spiral channel formed therein with an inlet at one end of the channel and an air filled reservoir at the other end. A movable piston is in a chamber that is filled with mercury and in communication with the inlet of the channel. A faceplate and indicia film are ultrasonically welded to the body to complete the channel and reservoir. A spring in the chamber urges the piston toward a rest position. A sensing device moves the piston in response to displacement of a workpiece. A compensating screw communicates with the chamber for correcting for temperature changes. A cylindrical, relative displacement indicator is also disclosed and includes a clear body with a straight channel therethrough that is in communication with a piston that is movable in a mercury filled chamber and is operated by a sensor. An upper cap enables in line mounting of the indicator in the chuck of a tool, such as a drill press.
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