Contour measuring apparatus

Abstract

A contour measuring apparatus including a stylus for contacting an outer surface of an object to be measured, a support arm having mounted at the distal end thereof of the stylus, a slider movable in parallel with the longitudinal directon of the support arm and oscillatingly movable and pivotally supporting the support arm about a horizontal axis perpendicularly intersecting the longitudinal direction of the support arm, a feed screw shaft threadably coupled to the slider so as to move the slider in parallel with the longitudinal direction of the support arm and a differential transformer mounted between the support arm and the slider. The counter measuring device further includes a driven gear mounted at one end of the screw shaft, a first clutch connected by way of an idle gear meshing with the driven gear and a driving gear, a motor connected to the first clutch, a second clutch coaxially connected to the driven gear, a manual handle connected to the second clutch and a rotational angle detecting device for digitally detecting the rotation of the screw shaft. In a preferred embodiment, the rotational angle detecting device includes a case, a shaft rotatably supported by the casing connected to the feed screw shaft, a rotational angle detecting disk operationally associated with the shaft, sensing means for sensing the rotation of the disk and transferring means for transferring either the disk or sensing means in a direction for compensating for backlash by an amount equal to the backlash of the feed screw shaft when rotation of the feed screw shaft is started.