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:
Oct. 20, 1992
Filed:
Feb. 22, 1991
Colin McHardy, Aberdeen, GB;
Abstract
In a downhole assembly (1) including an outer casing or mandrel (2), an axially movable prong (11) in the mandrel, and means for equalizing pressure within the mandrel (1) comprising a fluid duct (7) communicating the interior of the mandrel with the outside and a control member (or melon) (8) movable by the prong to control fluid flow via said duct (7); there is provided apparatus for controlling movement of the prong (11) comprising radially movable arrester dogs (14) engagable with a rib (20) on the prong (11) and an annular piston device (15) located in a housing (16) adapted for operative movement of the dogs (14). In particular housing zones on either side of the piston device (15) are maintained at tool external and mandrel internal pressure respectively whereby the piston device (11) is moved to lock the prong (11) when there is a pressure imbalance but free the prong (11) when pressure equilibrium is reached.