Pneumatic tool with self-sealing diaphragm valve system

Abstract

A fastener driving device comprises a housing having a chamber constructed and arranged to contain compressed air, a cylinder disposed within the housing, a piston disposed within the cylinder and movable between upper and lower positions within the cylinder, a fastener striker connected with the piston, a main valve and trigger valve. The main valve is formed from a resilient material having a first portion thereof sealingly engaged with a first portion of the cylinder. The main valve has a second portion thereof movable between a sealing position with a second portion of the cylinder and an unsealed position as a result of flexing of the resilient material. The unsealed position permitting the compressed air to force the piston to move from the upper position to the lower position to enable the fastener striker to move through a fastener driving stroke. The trigger valve is carried by the housing. The trigger valve is actuatable to air pressure in the vicinity of the main valve to enable the second portion of the main valve to move from the sealing position to the unsealed position.