Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
1999-04-28
2001-07-24
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S057350, C081S057190
Reexamination Certificate
active
06263763
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to power tongs and backup tongs used for making and unmaking joints between threaded tubulars.
BACKGROUND OF THE INVENTION
Making and breaking threaded joints of tubulars used in oil and gas drilling and production is typically accomplished using a backup tong and a power tong.
Lateral and axial forces on the threaded joints imparted by the power tong or the backup tong may cause damage to them. The power tong system described here provides reduction of lateral and axial forces on the joints.
SUMMARY OF THE INVENTION
In a first power tong system, lateral forces on joints are reduced by providing the power tong with a guide system that constrains the power tong against movement.
There is thus provided according to an aspect of the invention, a power tong system, comprising a frame having a rear support and a front support, the front support comprising a first front leg and a second front leg; and a power tong mounted in the frame with the power tong extending transversely between the first front leg and the second front leg, the first front leg and the second front leg forming a guide preventing transverse motion of the power tong while allowing vertical movement of the power tong. The system is also preferably provided with a backup tong. The constraint is preferably provided by using a roller on the sides of the power tong, to prevent excessive wear on the power tong and reduce friction between the tong and the guide. Supporting the power tong in a guide with roller bearings reduces bending or shear forces, while providing accurate torque readings and improved thread connections.
In a second power tong system, a load cell assembly is provided in which a load cell is linked by a series of links to the power tong such that movement by the power tong in either of two transverse directions loads the load cell. Two ways of accomplishing this are also provided, though others are possible.
In a third power tong system, an improved backup tong is provided in which jaws, preferably symmetrically disposed on the backup tong and each carrying dies, are moved about pivots by a rigid link between the jaws and a linear actuator. The dies are preferably provided with more than one die seat for locating the dies at different positions on the jaws. This makes the power tong capable of biting casing and a coupling with the same jaws, thus eliminating the need to change jaw sizes, or using additional jaw sets. A third die may be provided, preferably symmetrically arranged with the dies on the jaws. The third die may be located on the linear actuator.
The characteristics of the first, second and third power tong systems are preferably combined in a single system.
These and other aspects of the invention are described in the detailed description of the invention and claimed in the claims that follow.
REFERENCES:
patent: 3308691 (1967-03-01), Guier
patent: 4099429 (1978-07-01), Hauk
patent: 4402239 (1983-09-01), Mooney
patent: 4649777 (1987-03-01), Buck
patent: 4732061 (1988-03-01), Dinsdale
patent: 5099725 (1992-03-01), Bouligny, Jr. et al.
patent: 5537900 (1996-07-01), Schaar
patent: 5542318 (1996-08-01), Wesch, Jr.
patent: 5664310 (1997-09-01), Penisson
patent: 5791206 (1998-08-01), Daigle et al.
patent: 5819604 (1998-10-01), Buck
patent: 2097089 (1998-02-01), None
Brochure entitled Hydraulic Backup With SE BTM & TL Systems, Universe Machine, Edmonton, Alberta, Canada, printed in Canada on Mar. 26, 1999, 2 pages.
Barker Marcin K.
Feigel, Jr. Kurt R.
Pohnert Vladimir G.
Lambert Anthony R.
Meislin D. S.
Universe Machine Corporation
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