Abstract: A drilling machine is provided with a quill feed device for reciprocating a quill, a driving member and a driven member, disposed between a spindle rotatably supported by the quill and a driving source therefor in such a manner as to produce a relative angular displacement therebetween according to magnitude of a load applied on a tool held by the spindle, a detector generating a series of pulse signals correlated to the relative angular displacement between both members, a counter numerically counting the pulse signals generated from the detector in respect of one rotation of the spindle, a memory memorizing numerical data, corresponding to the relative angular displacement while the tool being separated from a workpiece, counted by the counter device, and a comparator for comparing the value memorized in the memory and an actual counted value in the counter.

Abstract: An apparatus for detecting torque transmitted between two rotary members. A driving member and a driven member are connected via a transmission spring, permitting relative angular displacement therebetween. On either one of the two rotary members a wheel disk having a number of slits arranged in a circle is provided. A detector, such as a photocoupler, for detecting the slits is disposed on a frame adjacent to the wheel disk. A shutter disk with a shutter portion for partially covering the slits is attached to the other rotary member at an opposed posture to the wheel disk. The number of slits detected by the detector is varied according to the relative angular displacement between the driving member and the driven member while they are in rotation, and the torque between both rotary members may be numerically determined from the number of slits detected.