Patent ID: 6193451
Filing Date: 2001-02-27
Classification: B23B,Y10T

Abstract:
A holder adapted for detachably holding a cutting tool, said holder comprising:a house having an internal cavity;a clamping mechanism mounted in the cavity and including:a clamp element adapted for clamping a tool, andan actuating mechanism for moving the clamp element to a tool-clamping position, the actuating mechanism including a piston mounted for reciprocation in the cavity, the piston dividing the cavity into first and second chambers, the first chamber communicating with a source of pressurized hydraulic fluid for displacing the piston in a direction causing the clamping element to clamp a tool against the house,the piston including a passage formed therein and communicating the first chamber with the second chamber, a valve disposed in the passage and biased to a passage-closing position for normally blocking communication between the first and second chambers, the valve being exposed to pressure in the first chamber and movable by pressurized fluid in the first chamber to a passage-opening position to relieve pressure in the first chamber when a tool is clamped and the pressure in the first chamber exceeds a predetermined value.