Abstract: In a feed control system, a feed controller controls a servomotor in such a manner as to reduce the difference between an objective position and a present position of a movable body. An interference detection circuit coupled to the feed controller detects the occurrence of an interference between the movable body and an obstruction when feed movement of the movable body is discontinued nevertheless the difference between the objection and present positions does not reach zero. A digital computer is coupled to an objective position counter provided in the feed controller to selectively set therein objective positions to which the movable body is to be positioned successively. The digital computer, when receiving a signal from the interference detection circuit, sets the objective position counter with data for moving the movable body a predetermined amount in a direction opposite to that wherein the movable body was moved before the occurrence of an interference.

Abstract: A contact detecting apparatus for detecting the contact of a workpiece and a tool which comprises a coil mounted on the periphery of a spindle head and connected to an AC power source for generating an induced current in a first looped secondary circuit formed by the workpiece, a work table, a machine bed, a column, a spindle head, a tool spindle and a tool in the tool spindle when the workpiece and the tool are moved relatively into contact with each other, and a second looped secondary circuit formed by a tool change device, the tool, the tool spindle and the spindle head when a tool change operation is performed. A detector is connected between the AC power source and the coil for detecting a change in an electrical signal caused by contact between the workpiece and the tool or contact between the tool change device and the tool to output a contact detecting signal. Another detector is provided to detect that a contact detecting signal is not generated, even if a tool change operation has been performed.

Abstract: An automatic centering controller for centering the axis of a tool spindle of a numerically controlled machine tool on the axis of a reference circumferential surface of an article mounted on the machine tool. The controller comprises a touch sensing device mounted in the tool spindle for detecting the touch of a probe thereof with the reference circumferential surface, a pulse generator for applying feed pulses to servomotors through a numerical controller so as to move the tool spindle along X and Y-axes, and a pulse control device connected to the touch sensing device, the numerical controller and the pulse generator.

Abstract: An index device for indexing a rotatable magazine, having a plurality of tool holding devices which store a variety of tools and are addressed in a numerical order, to a predetermined tool change position for a tool exchange operation. A check signal is generated each time a specific tool holding device having an address of a predetermined binary coded state is indexed to the tool change position. A memory device stores a binary coded number of a tool holding device indexed at the tool change position. An abnormality is checked in accordance with a check signal and a content of the memory device.

Abstract: In an automatic tool change apparatus, numbers of tools stored in respective tool holding devices mounted on a magazine and held in a spindle are identifiable whether the tools are large or small ones. A combination of a tool held in the spindle and a tool commanded by NC data is discriminated to selectively perform a normal or special cycle of a tool change operation.

Abstract: A control apparatus for a machine tool having a tool support supporting a tool for machining a workpiece and movable relative to the workpiece through a feed screw is disclosed. When the tool support is moved to a position in the vicinity of an original position, a signal indicator generates an output signal. In response to the output signal, one of reference pulses generated in response to the relation of the feed screw is specified to define the original position. A digital switch sets a distance between the original position and a start position. The tool support is moved toward the workpiece by the distance set by the digital switch from the original position defined by the specified reference pulse.