Trigger valve apparatus for a pneumatic tool

摘要

A plunger is shiftable in response to a trigger operation by a user. A valve piston has a valve piston chamber therein for slidably accommodating the plunger and an axial bore into which the plunger is inserted. An air passage connects the valve piston chamber to an atmosphere via a clearance between the plunger and the axial bore of the valve piston. A seal member is provided to seal the clearance between the plunger and the axial bore of the valve piston. And, a relief passage is formed on at least one of the plunger and the axial bore of the valve piston to open the air passage, thereby allowing compressed air to exit from the valve piston chamber to the atmosphere under a condition where the plunger is engaged with the axial bore of the valve piston.