Chucks or sockets – Accessory or component – Jaw insert
Reexamination Certificate
1999-10-22
2001-10-16
Bishop, Steven C. (Department: 3722)
Chucks or sockets
Accessory or component
Jaw insert
C175S423000, C269S268000, C269S279000, C269S283000
Reexamination Certificate
active
06302410
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention relates to an apparatus for grasping cylindrical bodies such as pipes and rods, in particular to a rod gripping jaw for use in directional boring.
BACKGROUND OF THE INVENTION
In order to meet the need for boring under or through obstructions such as roadways, concrete lined waterways and large underground utilities, systems for underground directional boring were developed. A directional borer generally includes a series of drill rods or pipe sections joined end to end to form a drill string. The drill rods or pipe sections are typically connected with threaded couplings. The drill string is pushed or pulled though the soil by means of a powerful hydraulic device such as a hydraulic cylinder. See Malzahn, U.S. Pat. Nos. 4,945,999 and 5,070,848, and Cherrington, U.S. Pat. No. 4,697,775 (RE 33,793). The drill string may be pushed and rotated at the same time as described in Dunn, U.S. Pat. No. 4,953,633 and Deken, et al., U.S. Pat. No. 5,242,026. A spade, bit or head configured for boring and steering is disposed at the end of the drill string and may include an ejection nozzle for water to assist in boring.
The pipe sections used in drill strings are typically steel pipe having a diameter of from about one to eight inches, more often four to eight inches. During drilling, rod or pipe sections are added as the bore is advanced and removed when the tool is retracted for replacement or repair. Thus, as the pipe or rod is being advanced, it is necessary to couple and tighten additional sections of pipe to the drill string. Conversely, when the drill string is removed from the bore, it is necessary to loosen and decouple adjacent pipe sections.
Making and breaking joints between adjacent pipe sections in a drill string is generally accomplished with a hydraulic vise that having two adjacent pairs of jaws that grip adjacent sections of pipe and rotate the front section to engage or disengage a threaded pipe coupling. Such coupling and decoupling apparatus is known in the art. The rod gripping jaws should securely grasp of the pipe section without applying enough force to crush it or damage its surface.
Conventional pipe or rod gripping jaws are typically fabricated from steel or a steel alloy and have knurled surfaces to aid in grasping the pipe section. However, the effective life of conventional steel jaws for use in directional boring machines is limited. While the use of steel projections or knurled surfaces on rod gripping jaws may aid in gripping the surface of a steel pipe section, the steel-on-steel gripping action rapidly wears the gripping surfaces of the jaw. Thus, there exists a need for an improved rod gripping jaw, and in particular, an improved rod gripping jaw adaptable for use in connection with directional boring machines.
SUMMARY OF THE INVENTION
The invention provides an improved jaw for gripping a cylindrical object such as a drill rod used in a directional boring machine. The body of each jaw has a front face on which a plurality of teeth or studs are mounted. These teeth are made of a material harder than the jaw body and are positioned to engage an outer rounded rod surface. The improved jaw of the invention is particularly suitable for use in connection with directional earth boring machines which must grasp, couple and decouple section of drill string during the drilling operation. The teeth are preferably arranged in an array or formation that permits the teeth to grip a semi-cylindrical portion of a rod or pipe surface evenly, and the number of teeth is such that each tooth tip digs into the outer surface of the pipe or rod a sufficient depth to securely hold the rod, but not so deeply that the rod surface is scored excessively. In one embodiment, the teeth are oriented radially inwardly toward a longitudinal axis defined by a lengthwise concave recess in the front face of the jaw.
In another aspect, a tool for gripping a rod including a pair of jaws is provided. Each of the jaws comprises a steel jaw body with a concave surface in its lengthwise direction, thereby being adapted to engage a curved surface. Each of the jaws is provided with a plurality of studs having conical tips with points configured to penetrate and grip an outer surface of a curved cylindrical steel member. The studs are made of a material harder than the jaw body and configured to project from the jaw to provide a clearance between the concave surface of the jaw and the outer surface of the curved cylindrical member upon engagement of a rod or similar body.
A clamp assembly according to the invention configured for use in a directional boring machine includes a U-shaped clamp having a pair of first and second arms. A movable stem jaw is mountable against an inside wall of the first arm, and a vise jaw which may be movable or fixed is mountable against an inside wall of the second arm in a position opposed to the movable jaw. Suitable means may then be provided for securing the vise jaw in position against the inner wall of the second arm. Similarly, means such as a annular flange welded to the rear face of the stem jaw extends through an opening in the first arm for movably supporting the stem jaw for movement towards and away from the vise jaw. The vise and stem jaws are each provided with teeth or studs according to the invention as described above.
REFERENCES:
patent: Re. 33793 (1992-01-01), Cherrington et al.
patent: 2552618 (1951-05-01), Boatright
patent: 3975045 (1976-08-01), Abarotin et al.
patent: 4592682 (1986-06-01), Vanistendael
patent: 4953638 (1990-09-01), Dunn
patent: 5070948 (1991-12-01), Malzahn et al.
patent: 5253721 (1993-10-01), Lee
patent: 5778991 (1998-07-01), Runquist et al.
patent: 5799740 (1998-09-01), Stephenson et al.
patent: 5899283 (1999-05-01), Cox
Vermeer Manufacturing Company Website, “Directional Boring Equipment,” 1 page.
Earth Tool Company, D7×11A Navigator, Clamp Assembly Figure 9-2, 1997, 1 page.
Earth Tool Company, D7×11A Navigator, Rotation Cylinder Assembly Figure 9-5, 1997, 1 page.
Earth Tool Company, D7×11A Navigator, Clamp Cylinder Assembly Figure 9-6, 1997, 1 page.
Crane Robert F.
Wentworth Steven W.
Bishop Steven C.
Earth Tool Company L.L.C.
Intellectual Property Law, P.C
Meyers Philip G.
LandOfFree
Rod gripping jaw does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rod gripping jaw, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rod gripping jaw will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611592