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:
Dec. 04, 1990
Filed:
Jun. 09, 1989
Rex E Duhn, Bakersfield, CA (US);
Jay C Duhn, Bakersfield, CA (US);
William D Chapman, Bakersfield, CA (US);
Duhn Oil Tool, Inc., Bakersfield, CA (US);
Abstract
A ground subsidence wellhead has a lower wellhead assembly mounted on the ground for supporting a casing in tension and an upper wellhead assembly threaded to the top of the casing and spaced from the lower wellhead assembly. The lower assembly has a casing head with aconical bowl for receiving a slip. The slip is wedged between the casing head and casing by compression springs acting between the casing head and the slip, and has asymmetrical teeth for engaging the casing to prevent downward, but allow upward, movement of the casing in the slip.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile