Spindle apparatus for supporting and rotating a workpiece

摘要

A spindle apparatus for supporting and rotating a workpiece in a grinder. The spindle apparatus includes a workpiece spindle rotatably supported on a spindle head and driven for rotation by a motor, and a spindle plate mounted to the front end of the workpiece spindle and including an eccentric drive pin. The workpiece spindle has a bore in which a ram is axially movable. A center is fit in the front end of the ram. A unit is provided to advance the ram to engage with one end of the workpiece when the workpiece is to be supported. A rotary sleeve is rotatably supported on the front end of the ram and includes an engagement portion which is displaceable in the axial direction of the spindle and engageable with the drive pin in the direction of rotation. A driving unit is mounted to the front of the rotary sleeve to engage the workpiece in the direction of rotation when the ram is in its advanced position to thereby transmit rotation.