Patent ID: 7637188
Filing Date: 2009-12-29
Classification: B23B,B23Q,Y10T

Abstract:
1. A workpiece ejecting device for a machine tool including a head stock, a spindle installed rotatably at the head stock, a chuck installed at a front end surface of the spindle to clamp the workpiece, a drawing tube installed at the inside of the spindle as a hollow shaft and connected at a front end thereof to the chuck to rotate integrally with the spindle, and a chucking cylinder installed at the head stock so that it can clamp or unclamp the workpiece clamped at the chuck by moving the drawing tube forward and rearward in the axial direction, the workpiece ejecting device comprising: an ejecting cylinder mounted at one side of the head stock in such a fashion that its center is aligned with the center of the spindle; an ejecting rod adapted not to rotate and having a length extending from the hollow inside of the drawing tube to a position adjacent to the chuck, the ejecting rod being axially formed at the inside thereof with a fluid passing opening, and being moved reciprocally in the axial direction as a rod for the ejecting cylinder by means of the ejecting cylinder to thereby push the unclamped workpiece from the chuck to the outside; and a front bearing unit installed between an inner peripheral surface of the drawing tube opposite to the ejecting cylinder and an outer peripheral surface of the ejecting rod so that it can support the rotation of the drawing tube.