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US 7,028,785 B2Granted
Pneumatic impact piercing tool
AssigneeEarth Tool Company, L.L.C.
InventorMark D. Randa
Life of this patent
Estimating the term…
Abstract
A pneumatic ground piercing tool includes a tail assembly including a tail nut and tail cap, the tail cap having a plurality of discharge ports for exhausting spent compressed air, the discharge ports opening into an annular space between a rearwardly opening recess of the tail cap and an air supply conduit such that the exhaust ports are shielded by a side wall of end cap from plugging when the ground piecing tool is operated in reverse mode.
Claims17
A pneumatic ground piercing tool, comprising:
- an elongated hollow body having a front nose and a rear opening;
- a striker disposed for reciprocation within an internal chamber of the body to impart impacts thereto for driving the body through the ground;
- a stepped air inlet conduit which cooperates with the striker within the internal chamber of the body to reciprocate the striker and impart blows to a front end wall of the internal chamber under the action of a pressure fluid fed into the rear recess in the striker;
- a tail assembly mounted in the rear opening of the body having exhaust passages therethrough, at least a potion of each exhaust passage angling radially inwardly to communicate with a central hole at the rear end of the tail assembly whereby exhaust escapes through the central hole, the tail assembly including a tail nut threadedly secured to the body inside the rear opening thereof and having a plurality of threaded, rearwardly opening holes therein, an end cap disposed to fit over the rear opening of the body, the end cap having openings therein in alignment with the threaded holes in the tail nut and forming the central hole through which the air inlet conduit passes;
- and
- a plurality of bolts which extend through the openings and are threadedly secured in the threaded holes in the tail nut so that the end cap is securely clamped to the tool body and an axial clamp load is applied to the tail nut.
3 more elements
A pneumatic ground piercing tool, comprising:
- an elongated hollow body having a front nose and a rear opening;
- a striker disposed for reciprocation within an internal chamber of the body to impart impacts thereto for driving the body through the ground, the striker having a rearwardly opening recess and a rear radial passage through a wall enclosing the recess, a front portion having a front bearing thereon for sliding contact with a first inner surface of the body and passages permitting flow of pressure fluid to a front, variable-volume pressure chamber ahead of the striker, and a rear portion having a rear bearing thereon rearwardly of the radial passage for sliding contact with a second inner surface the body;
- a stepped air inlet conduit which cooperates with the striker within the internal chamber of the body to reciprocate the striker and impart blows to a front end wall of the internal chamber under the action of a pressure fluid fed into the rear recess in the striker, followed by reverse movement of the striker when the rear radial passage moves past a front edge of the step of the stepped air inlet conduit, and exhaust of compressed air when the rear radial passage moves past a rear edge of the step of the stepped air inlet conduit;
- and
- a tail assembly mounted in the rear opening of the body that secures the air inlet conduit in the body, wherein the tail assembly has exhaust passages therethrough, at least a potion of each exhaust passage angling radially inwardly to communicate with a central hole at the rear end of the tail assembly, whereby exhaust escapes through the central hole.
2 more elements
Dependencies are inferred from the claim text.