Patent ID: 8640939

Claim:
An explosively actuated fastener driving tool comprising a barrel mounted to a receiver of the tool, a driving piston within the barrel for driving a fastener at the forward end of the barrel upon firing of the tool, and a retractor pawl assembly for resetting the piston into a rear end of the barrel by forward movement of the barrel relative to the receiver following firing, wherein the retractor pawl assembly comprises a retractor pawl having a head including a shoulder adjacent thereto, wherein said head is extendible through a slot in the barrel to engage and retain the piston during forward movement of the barrel, the pawl being mounted in a housing fixed relative to the receiver and being spring biased to move radially into and out of the interior of the barrel by movement of the barrel relative to the receiver, and a release member operable to fully withdraw the pawl from the barrel to permit removal of the barrel from the receiver, the release member being mounted to the housing in such a manner that in a normal condition of the tool it cannot be moved to a position at which the pawl assembly is detached from the receiver, and a roll pin configured to engage said shoulder for retaining the pawl within the housing.