Abstract: A drive link is coupled to an end of a ratchet wheel, and the other end of the drive link is slidably arranged in a guide hole formed in a side wall of a nose holder. The nose holder has a control plate rotatably attached to the other end of the drive link. The control plate is urged by a spring so as to engage with the other end of the drive link with such a strength as to temporarily stop the movement of the drive link when the drive link is in the course of retreating together with the nose portion. The other end of the drive link is designed to engage with a front end of the guide hole while the nose portion is in the course of advancing from a retreat end. By causing the ratchet wheel to make a forward/backward rotation based on stoppage of the drive link while the nose portion is in the course of retreating and while the nose portion is in the course of advancing, a feed wheel is rotated intermittently in a coupled screw feed direction.

Abstract: The controlling apparatus includes a wire supplying sensor 18 for detecting a number of rotations of a wire supplying motor 8, a wire twisting sensor 49 for detecting actuation of a loaded torque detecting mechanism c, and a return position detecting sensor 38 for detecting that a wire twisting mechanism b is located at a predetermined waiting position. In response to an output signal from the wire supplying sensor 18, the controlling apparatus stops rotation of a wire supplying motor 7a and rotationally drives a wire twisting motor 7b. In addition, in response to an output signal from the wire twisting sensor 49, the controlling apparatus shifts rotation of the wire twisting motor 7b in the normal direction to rotation of the same in the reverse direction. Additionally, in response to an output signal from the return position detecting sensor 38, the controlling apparatus stops rotation of the twist driving motor 7b.