Explosively actuated tools
AssigneeCetram Pty Limited
InventorDavid John McCullough
Life of this patent
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Abstract
A firing mechanism of an explosively actuated tool for driving a fastener into a substrate includes a cocking rod and sear for entraining the firing pin with the firing pin being releasable on cocking by rotation of the sear. The cocking rod and sear form a structure subject to an axial and rotational bias by a coil spring anchored at one end to the structure and at the opposite end to a mounting which during assembly of the mechanism is rotated to apply torsional loading to the spring and is then locked into a housing of the mechanism in an angular orientation in which torsional loading is maintained in the spring.
Claims14
An explosively actuated tool for driving a fastener into a substrate, said tool having a barrel, a piston displaceable in the barrel on firing of the tool to drive a fastener from the forward end of the barrel into the substrate upon firing of a charge, and a firing mechanism including a firing pin, and a rotary sear pivotal between a position in which the sear entrains the firing pin and a position in which the sear is released whereby the firing pin is driven towards the charge to thereby fire the charge, wherein the rotary sear is carried by a cocking rod, and the cocking rod and the sear carried thereby is subject to a rotational and axial bias by a spring anchored at one end relative to the cocking rod and at the other end to a mounting, the mounting being rotatable to apply torsional loading to the spring and being lockable to a housing of the cocking rod in an angular orientation in which torsional loading is maintained in the spring.
A method of assembling an explosively actuated tool for driving a fastener into a substrate, said tool having a barrel, a piston displaceable in the barrel on firing of the tool to drive a fastener from the forward end of the barrel into the substrate upon firing of a charge, and a firing mechanism including a firing pin, and a rotary sear pivotal between a position in which the sear entrains the firing pin and a position in which the sear is released whereby the firing pin is driven towards the charge to thereby fire the charge, the rotary sear being carried by a cocking rod for axial and rotational movement therewith in a housing for the firing pin and cocking rod, wherein said method includes:
- anchoring a forward end of a compression coil spring to the structure formed by the cocking rod and rotary sear carried thereby;
- anchoring a rear end of the spring to a mounting;
- rotating the mounting about the axis of the coil spring to apply a torsional loading to the spring;
- and
- locking the mounting to the housing in a predetermined angular orientation in which torsional loading is maintained in the spring, the spring thereby providing a forwards axial bias to the cocking rod and sear, and a rotational bias to the cocking rod and sear in a sense to pivot the sear into engagement with the firing pin.
An explosively actuated tool for driving a fastener into a substrate, said tool having a barrel, a piston displaceable in the barrel on firing of the tool to drive a fastener from the forward end of the barrel into the substrate upon firing of a charge, and a firing mechanism including a firing pin, and a rotary sear pivotal between a position in which the sear entrains the firing pin and a position in which the sear is released whereby the firing pin is driven towards the charge to thereby fire the charge, wherein the rotary sear is carried by a cocking rod, and the cocking rod and the sear carried thereby is subject to a rotational and axial bias by a spring anchored at one end to the structure formed by the cocking rod and sear and at the other end to a mounting, the mounting being rotated during assembly of the firing mechanism to apply torsional loading to the spring and then being locked to a housing of the cocking rod and firing pin in an angular orientation in which torsional loading is maintained in the spring.
A firing mechanism of an explosively actuated tool for driving a fastener into a substrate, said mechanism including a cocking rod with a sear for entraining a firing pin with the firing pin being releasable or cocking by rotation of the sear, the cocking rod and sear forming a structure subject to an axial and rotational bias by a coil spring anchored at one end to the structure and at the opposite end to a mounting which during assembly of the mechanism is rotated to apply torsional loading to the spring and is then locked into a housing of the mechanism in an angular orientation in which torsional loading is maintained in the spring.
Dependencies are inferred from the claim text.