Apparatus for installing explosively driven fasteners

A tool for installing an explosively driven fastener, the fastener including a nail and an explosive load attached to the nail, the tool comprising:

• an outer cover sleeve defining a bore, a longitudinal axis, a proximal end and a distal end;
• a generally tubular trigger body fixedly positioned in the outer cover sleeve, the bore of the trigger body having a distally facing arcuate backstop face;
• an end cap positioned at the proximal end of the trigger body securing the trigger body to the outer cover sleeve;
• a firing pin holder located within the bore of the generally tubular trigger body and extending along the longitudinal axis thereof, the firing pin holder having a proximal end and a distal end;
• a firing spring arranged to bias the firing pin holder distally with respect to the trigger body;
• a firing pin having a proximal end and a distal end, the distal end being pointed, the firing pin being separate from the firing pin holder, the proximal end of the firing pin being removably coupled to the distal end of the firing pin holder;
• a nosepiece having a proximal end and a distal end, the proximal end arranged to receive a firing pin guide and the distal end arranged to receive the fastener comprising the nail and the explosive load such that when the fastener is placed in the distal end of the nosepiece and the firing pin holder is biased out of the outer cover sleeve by the firing spring, the firing pin strikes the explosive load causing the explosive load to explode and drive the nail out of the nosepiece,
• a nosepiece spring biasing the nosepiece distally,
• a tubular reset sleeve having an inner flange facing distally and an outer flange 30 facing proximally,
• wherein the firing pin guide is carried slidably in the reset sleeve, the firing pin guide having a distal end and a proximal end, the firing pin guide having a proximally facing outer arcuate flange abuttable against the inner flange of the reset sleeve, and an arcuate face at its proximal end abuttable against the inside distally facing arcuate backstop face in the generally tubular trigger body;
• a reset spring 36 mounted around the firing pin guide and abutting the outer flange of the reset sleeve, the reset spring biasing the reset sleeve distally;
• a trigger ball and a trigger ball spring mounted transversely in the firing pin holder, the trigger ball being biased radially outward from within the firing pin holder;
• wherein the firing pin guide has a slot extending from the proximal end and a widened area in the slot to receive the trigger ball,
• wherein
• when the tool is in an energized position, the trigger ball rests in the widened area of the slot thereby limiting distal movement of the firing pin, and the arcuate end face of the firing pin guide abuts or nearly abuts the arcuate backstop face in the trigger body.