Abstract: A vertical-type machining center having a spindle carrier which travels in the vertical direction and a turret capable of both rotation and upward and downward movement provided on the spindle carrier, wherein tools are automatically changed over through rotation of the turret caused by relative movement between the turret and the spindle carrier when the upward movement of the turret is checked by a restraining member. A Z-axis position pulse generator is provided on a spindle mechanism drive member, such as the vertical drive motor or a screw shaft, and is adapted to generate a pulse for each revolution of the drive member. The pulses are counted by a counter which delivers a counted value for use in computing the vertical position of the spindle mechanism. The arrangement is such that the rotational speed of the vertical drive motor is controlled so as to move the spindle mechanism at an optimum speed suitable for the vertical position thereof.

Abstract: An indexing table assembly adapted to be mounted on a machine tool or other industrial machine, comprising first and second screw elements coaxially engaged with each other and mounted for movement along their axes, mechanism for moving said first screw element along its axis, a turntable connected to said second screw element and movable therewith, mechanism preventing said second screw element from being moved beyond a predetermined range, said mechanism for moving said first screw element comprising a cylindrical piston directly connected to said first screw element, a circular fluid chamber in which said cylindrical piston is mounted for movement, said cylindrical piston separating said chamber into first and second chambers, a source of pressurized fluid, a control valve for controlling the flow of pressurized fluid into either said first chamber or said second chamber with the result that when the pressurized fluid flows into said second chamber the first screw element is moved positively in one directi

Abstract: In a spindle control system in which a pulse coder is coupled with a spindle; a pulse train signal, derived from the pulse coder upon each rotation of the spindle through a predetermined rotational angle, is converted into an analog signal corresponding to the actual rotational speed of the spindle; and the analog signal is compared with a commanded speed signal to drive the spindle at the commanded speed. Upon application of a command for stopping the spindle at a predetermined position, a predetermined numerical value is set in an error register in accordance with a specified position signal from the pulse coder, the pulse train signal from the pulse coder is fed back to the error register, and the rotational position of the spindle is controlled with a signal corresponding to the content of the error register.

Abstract: Disclosed is a machine tool which comprises a spindle head, and an automatic tool changing apparatus which comprises a tool release mechanism adapted to be operated by movement of the spindle head in the direction of axis of the spindle and a tool magazine supported in floating manner with respect to the direction of the axis of spindle. When the spindle head is axially moved away from the tool magazine with the tool in the spindle being held by the tool magazine, in order to remove the tool from the spindle the tool is released from engagement with the spindle by a release mechanism, and the tool magazine can be moved together with the spindle head until the tool has been released.

Abstract: There is disclosed a machine tool, of the type having a tool magazine for receiving tools therein, and wherein a spindle head is moved in the direction of the axis of a spindle relative to the tool magazine such that one of the tools in the tool magazine is engaged with or disengaged from the spindle. A draw bar for firmly attaching a tool to the spindle is positioned inside of the spindle. The operation of the draw bar is actuated by the movement of the spindle head relative to the tool magazine.

Abstract: Disclosed herein is a machine tool consisting of a bed, a fast head stock mounted on the bed and a main spindle rotatably supported by the fast head stock, and wherein the main spindle is an integral part of an output shaft of an electric motor.