Numerically controlled transfer machine

摘要

A numerically controlled transfer machine comprises a rotary index table having thereon a plurality of jig tables for holding workpieces, and a plurality of working units are disposed in spaced relation around the index table so that rotary indexing of the index table successively positions the jig tables opposite different ones of the working units. Each working unit includes a positioning feed mechanism for controlling the feeding and return movements of the working unit to enable a working operation to be carried out on the workpieces. Each working unit has a position detector comprised of a microswitch mounted on a slide member slidably mounted on the working unit. A biasing spring urges the slide member in the direction of return movement of the working unit and a stopper comes into contact with and actuates the microswitch during the course of return movement to thereby feed an origin reference signal to the positioning feed mechanism to effect positioning of the working unit at a preselected origin return position. In the event of continued return movement past the origin return position, the stopper comes into contact with and pushes the slide member against the force of the biasing spring thereby preventing damage to the microswitch.