The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1976
Filed:
Jun. 27, 1972
Thomas L Elliston, Hurst, TX (US);
Other;
Abstract
A workover rig for lifting or lowering oil well pipe into a well casing is disclosed. The rig has a mast structure adapted to communicate hydraulic fluid to a drive cylinder which actuates a pulley system operably connected to a pipe hoist or traveling block with remotely operable pipe engaging grips. The dynamic loading on the mast is minimized by the drive cylinder which is affixed to a cross head at the mast crown and the fluid pressure force in the mast which automatically compensates for shock and weight loads on the mast. A hydraulic control system is operative in a regenerative high speed mode to permit multiple speed operation of the hoist. The structure is adapted to be supported at the well casing to transfer the load from the oil well platform to the casing. The method includes operating the mast in conjunction with an adjustable tension winch to efficiently transfer pipe between the mast and pipe storage area.