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:
Mar. 28, 1995
Filed:
Dec. 08, 1993
Melvyn F Whitby, Houston, TX (US);
David L O'Donnell, Houston, TX (US);
Varco Shaffer, Inc., Houston, TX (US);
Abstract
A ram assembly for positioning within a through bore of a blowout preventer body includes first and second opposing ram pistons each powering a respective knife blade. Each knife blade may have a pair of angled shear edges on opposite sides of the respective ram centerline, with each pair of angled shear edges defining a generally V-shaped configuration. The pair of opposing knife edges preferably engage the oilfield tubular at four contact points spaced substantially equidistant about a circumference of the tubular, and thereby contain the tubular for the shearing operation. According to the method of the present invention, the oilfield tubular is sheared substantially by brittle shearing rather than ductile shearing. By containing the tubular prior to shearing, the body of a shearing assembly may have a bore only slightly greater than the diameter of tubular to be sheared, thereby significantly reducing the costs and increasing the versatility of the shearing equipment, and also reducing the cost of the blowout preventer and the associated wellhead stack.