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:
Jul. 14, 1981
Filed:
Feb. 23, 1979
E Edward Rankin, Aberdeen (Dyce), GB;
Other;
Abstract
An apparatus for retrieving drill collars in an earth boring drill string when stuck. A sub is connected between two drill collars at various points. Each sub is a cylindrical member with a reduced annular or notched area at one point that is no greater in wall thickness than the drill pipe. A locator is secured to a wire line and lowered into the drill string to the vicinity of one of the subs located above the stuck point. The locator carries an explosive charge of capacity sufficient to cut drill pipe. The locator has a pivotal dog that engages a landing in the sub. The landing is spaced above the annular area a distance selected to position the explosive charge adjacent the annular area when the dog engages the landing.