Patent ID: 7008153

Claim:
A machine spindle comprising: a casing defining a center axis; and a clamping mechanism disposed in the casing, the clamping mechanism comprising: a front drawbar having axially spaced front and rear ends, the front end carrying a tool clamp operable to clamp a tool in response to rearward movement of the front drawbar, a rear drawbar arranged behind the front drawbar; a force transmitting mechanism for transmitting rearward motion of the rear drawbar to the front drawbar for movement of the front drawbar rearwardly, wherein the force-transmitting mechanism comprises a force-amplifier wedge arrangement; a gas spring for biasing the rear drawbar rearwardly comprising: a housing disposed in the casing and defining a gas chamber having a front wall disposed behind the wedge arrangement and through which the rear drawbar extends, and a piston disposed in the gas chamber for axial movement therein and releasably connected to a rear end of the rear drawbar by a releasable coupling disposed in the chamber.