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:
Sep. 08, 1987
Filed:
Jan. 17, 1986
Michael E McMahan, Duncan, OK (US);
Daniel A Newman, Duncan, OK (US);
Donald W Winslow, Duncan, OK (US);
Gary D Zunkel, Chickasha, OK (US);
Halliburton Company, Duncan, OK (US);
Abstract
An annulus pressure responsive downhole tool includes a housing with an operating element disposed in the housing. The operating element is movable from a first element position to a second element position relative to the housing. A hydrostatic well annulus pressure referenced annulus pressure responsive first power piston is disposed in the housing and movable from a first to a second position thereof relative to the housing in response to an increase in well annulus pressure. A lower than hydrostatic well annulus pressure referenced annulus pressure responsive second power piston is disposed in the housing and is operatively associated with the operating element for permitting the operating element to move from its first element position to its second element position in response to movement of the second power piston from a first position to a second position thereof relative to the housing. A prevention device is operatively associated with the first and second power pistons for preventing the second power piston from moving to its second position until the first power piston has moved at least part way towards its second position.