Pneumatic power tool

A pneumatic power tool, comprising:

• a housing having a pneumatic motor therein;
• a pressure air inlet passage in said housing;
• an air inlet opening adapted to be in fluid communication with said air inlet passage and defining an edge shaped valve seat;
• and
• a manually operable throttle valve assembly which is shiftable between a closed condition and an open condition, said throttle valve assembly including:
• a longitudinally displaceable valve stem having an outer end which carries a push button and an inner end which extends through said air inlet opening;
• and
• a valve unit for controlling the air flow through said air inlet opening;
• said valve unit including:
• a shoulder on said valve stem;
• a first valve element rigidly attached to said valve stem at a distance from said shoulder;
• and
• a second valve element displaceably guided on said valve stem between said shoulder and said first valve element, said second valve element including a non-resilient annular washer having a beveled contact surface for sealing cooperation with said edge shaped
• valve seat which is defined by said inlet opening;
• and said valve stem is formed with a passage extending axially through said second valve element and past said shoulder;
• wherein, when said throttle valve assembly is in said closed condition, said first valve element is arranged to cooperate sealingly with said second valve element, and said second valve element is arranged to cooperate sealingly with said edge shaped valve seat defined by said air inlet opening.