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:
Apr. 03, 1984
Filed:
Jun. 17, 1982
Allen E Bardwell, Front Royal, VA (US);
Other;
Abstract
A multiple drill stem for cable tool drilling operations, in which the drill stem is repeatedly hoisted and dropped to impact, has an internal hammer that moves a short distance to strike an anvil in a lower end of a drill stem casing. The improvement relates to a cocking spring that is positioned along an uppermost portion of the hammer and away from harmful debris that collects where the hammer strikes the casing anvil. The casing bears against an upper hammer anvil to cock the spring between a spring-compressing flange at one end and a restriction in the casing interior that blocks an opposite end of the spring, but allows the hammer to slide through it. The spring is further compressed when the drill stem is dropped to a point of initial impact, so that the hammer strikes a follow-up blow on the lower casing anvil. A method of assembling the drill stem is also disclosed.