Abstract: An explosively operated tool (1) for driving a fastener into a substrate such as steel or concrete has a resetting mechanism (12) for resetting a piston (10) of the tool into a rear part of a barrel assembly (8) of the tool after each firing of the tool. The barrel assembly (8) is mounted for axial movement within the tool housing (2) and co-operates with a mass mounted for rearwards movement relative to the housing (2) in opposition to a biasing force to absorb recoil on firing of the tool. The resetting mechanism (12) for resetting the piston (10) into a rear part (2a) of the barrel assembly after firing is powered in response to displacement of the mass on recall.

Abstract: A power actuated tool for driving a fastener such as a pin or nail into a substrate, has a fastener guide mounted at the forward end of a body of the tool for displacement axially inwardly relative to the body when the forward end of the tool is pressed against a substrate whereby to permit firing of the tool. A magazine carried by the tool for containing a plurality of fasteners mounted seriatim on segments of a carrier strip advances the leading end of the carrier strip and the fastener carried thereby into the fastener guide. A locking system for impeding firing of the tool is releasable in response to the presence of a fastener and associated segment of the carrier strip within the fastener guide whereby to permit firing of the tool only when a fastener is present within the fastener guide. The locking system thereby acts to prevent firing of the tool when the magazine is empty of fasteners and which could otherwise lead to damage occurring to the tool.

Abstract: According to the present invention there is provided an explosively-actuated tool for use in setting fasteners into a substrate, comprising a barrel (2), a driving piston (6) mount within the barrel for driving the fastener into a substrate upon detonation of an explosive charge positioned at or adjacent the rear of the barrel, a firing chamber (8) defined in the barrel rearwardly of the piston, and a system capable of controlling the power of the tool by controlled venting of combustion gases from the firing chamber. The power control system comprises an exhaust port arrangement (14) leading from the firing chamber through the wall of the barrel, and a control member (16) for controlling the effective open area of the exhaust port arrangement. Particularly advantageously, the end of the control rod is provided with a concave arcuate control edge (16b) which provides a relatively uniform relationship between displacement of the control rod and the degree of opening of the exhaust port arrangement.

Abstract: The barrel of a power actuated tool for driving a fastener into a substrate upon detonation of an explosive charge, comprises front (4) and rear (2) barrel sections mounted for telescopic movement to absorb recoil upon firing. The sections are held in assembled relation by a retainer element (14) and are such that assembly and disassembly can occur by manipulation of one barrel section relative to other without the need to remove the retainer element (14).