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, a bore of the trigger body having a distally facing arcuate backstop face;
• rotational positioning between the outer cover sleeve and the generally tubular trigger body being determined by a radial tongue or key on one of the outer cover sleeve and the generally tubular trigger body engaging a complementary groove or keyway in the other of the outer cover sleeve and the generally tubular trigger body;
• an end cap positioned at a 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 a 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 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 annular surface facing distally and an outer annular surface facing proximally,
• a firing pin guide, 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 face between the distal end and the proximal end abuttable against an inner arcuate face of the reset sleeve, and an arcuate face at its proximal end abuttable against the distally facing arcuate backstop face in the generally tubular trigger body;
• a reset spring mounted around the firing pin guide and abutting the outer annular surface 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 face at the proximal end of the firing pin guide abuts or nearly abuts the distally facing arcuate backstop face in the trigger body,
• said tool further comprising
• a grip extending transversely from the outer cover sleeve between the proximal end and the distal end,
• a trigger pivotally connected to the outer cover sleeve and biased distally away from the grip by a trigger spring positioned between the grip and the trigger, said trigger having an upper surface and a nose protruding from its upper surface toward the longitudinal axis of the outer cover sleeve, said nose entering the bore of the outer cover sleeve when the trigger is depressed toward the grip;
• wherein the generally tubular trigger body defines a longitudinally extending slot which receives the nose of the trigger when the trigger is depressed toward the grip,
• and when the tool is in a firing position, the trigger nose depresses the trigger ball out of engagement with the firing pin guide to allow distal movement of the firing pin under the action of the firing spring,
• wherein
• a key protrudes radially inwardly from an inside surface of the bore from near the proximal end of the cover sleeve, and
• a complementary longitudinally extending keyway is defined on an outside surface of the generally tubular trigger body beginning at the proximal end of the trigger body,
• the key being received by the keyway to retain the trigger body in a fixed rotational position in the cover sleeve, and said nose of the trigger riding in the longitudinally extending keyway when the trigger is biased distally away from the grip.