초록 ▼

An open-head Foster style backup tong has a number of pivoting jaws in mesh with a ring gear. A gap in the ring gear admits tubing into the center of the ring gear, where the tubing is gripped by the jaws when the ring gear is turned. The tong housing is open sided for convenient access and maintena

An open-head Foster style backup tong has a number of pivoting jaws in mesh with a ring gear. A gap in the ring gear admits tubing into the center of the ring gear, where the tubing is gripped by the jaws when the ring gear is turned. The tong housing is open sided for convenient access and maintenance, and the removable jaws are indexed for easy installation.

대표청구항 ▼

[ I claim:] [1.] A backup tong for use in making or breaking threaded joints in strings of tubing of oil and gas wells, comprising:a stem having an outer end for attachment to a support and an inner end, a housing supported at said inner end, a ring gear rotatable in said housing, a plurality of jaw

[ I claim:] [1.] A backup tong for use in making or breaking threaded joints in strings of tubing of oil and gas wells, comprising:a stem having an outer end for attachment to a support and an inner end, a housing supported at said inner end, a ring gear rotatable in said housing, a plurality of jaws pivoted to said housing and in mesh with said gear such that rotation of said gear in said housing is operative for pivoting said jaws between a retracted position and a gripping position, each of said jaws having a toothed end in mesh with said ring gear and an opposite end having a jaw face, said jaw face being fixed in relation to said toothed end, said ring is toothed along an interior circumference thereof and is rotatably supported at an outer circumference thereof between a plurality of outer bearings mounted to said housing, said housing having a pair of plates rigidly interconnected by said outer bearings and said plates held against said outer bearings by bolts passing through both said plates and each of said outer bearings, said ring gear being contained between said plates, characterized in that the annular continuity of said ring gear is interrupted by a gap for admitting tubing into the center of said ring gear for engagement by said jaws.