POSITION MEASURING APPARATUS

It is possible to, with a position measuring apparatus in a NC machine tool, a NC lathe, or the like that uses a load monitoring scheme, significantly reduce a response delay on the detecting jig side than those in the conventional apparatuses, and consequently measure the position of a measurement target with high accuracy. A measurement target (e.g., an advanceable and retractable center) is caused to abut a position detecting jig at the advanced end of the measurement target. In such a state, retracting and advancing motions of the measurement target are created to increase the load torque of a feed motor to a level sufficiently higher than the load torque that is detectable by the apparatus. After that, the abutment state between the measurement target (center) and the jig is canceled to cause a sudden drop in the load torque of the feed motor. Accordingly, it is possible to, even with a position measuring apparatus that uses a relatively low-cost load monitoring scheme, significantly reduce a response delay than those in the conventional apparatuses, and consequently measure a position with higher accuracy.