Patent ID: 7607373

Claim:
An adjusting device for a hand-held tool comprising: a body defining at least one fluid-filled cylinder internally thereof; a piston movable within said cylinder and carrying a contact member extending exteriorly from the cylinder for contact in use with a work piece to be retained by the tool; a fluid reservoir in communication with said cylinder; a valve being resiliently biased and interposed between said reservoir and the cylinder for the control of fluid to and from the cylinder; and an actuating member associated with the fluid reservoir for initiating fluid flow across the valve, the actuating member including a resiliently-biased plunger operable within the reservoir and carrying a stem contactable with the valve to selectively actuate said valve, the actuating member being so adapted whereby upon continued actuation during extension of the contact member the force acting upon the work piece through the agency of the contact member increases, the stem of the plunger being grooved for registration with the valve and the plunger is rotatable within the reservoir, rotation of the stem in use causing the valve to open to release pressure fluid from the cylinder into the reservoir thereby withdrawing the contact member.