Chuck with an integrated rotary union for fluid flow

Abstract

A chuck-actuating spindle assembly has a hollow shaft extending along and rotatable about an axis, a clamping bar parallel to and rotatable with the shaft and axially displaceable relative to the shaft to clamp and release an object carried on the shaft, and a rotary union for transmitting a fluid to the object carried on the shaft. The union has in turn a union housing nonrotatable about the axis, an annular bar seal face on the clamping bar, and a sealing member axially movable in the union housing independently of the bar face, forming a pressurizable space with the union housing, and having an annular member seal face axially confronting and axially engageable with the bar seal face. The seal faces form a portion of a passage extending from the space along the bar and shaft to the object. Rotation of the sealing member about the axis relative to the union housing is inhibited and the member is braced against the union housing axially away from the bar seal face with a predetermined biasing force. The space can be pressurized with a fluid and to press the member face against the bar face so that the fluid moves along the passage to the object.