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:
Feb. 03, 1981
Filed:
Dec. 31, 1979
William R Hadsell, Los Angeles, CA (US);
Tosh Miyagishima, Los Angeles, CA (US);
Hydril Company, Los Angeles, CA (US);
Abstract
A valve assembly for preventing a column of drilling fluid from spilling out of the lower end of a kelly includes an elongated body which has an axial opening and is threaded at both ends. A cam is rigidly mounted in the bore and a hollow piston in the opening is mounted for axial movement relative to the cam, the piston being shaped so that fluid pressure in the body will exert a downward force on the piston. A valve element is pivotally mounted in the piston (the piston inner surface defining a valve seat) and movable between a lower-closed position when the valve element is above the cam and engages the seat to an upper-open position where the cam engages the valve element and holds it away from the seat. A spring urges the valve element toward the closed position and the piston is urged upwardly in the bore so that the valve element is normally in its closed position. When a sufficient downward force caused by fluid pressure in the body is applied to the piston to overcome the upward force against the piston, the piston will move down causing the cam to engage and raise the valve element to its open position, the piston moving upwardly and the valve element returning to its closed position when the downward force is removed.