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:
Jun. 23, 1981
Filed:
Mar. 27, 1978
Floyd W Becker, Calgary, CA;
Richard R Regimbal, Calgary, CA;
Drill Systems, Inc., Calgary, CA;
Abstract
Multiple wall drill pipe adapted for use in a drill pipe string comprising an outer pipe member; an inner pipe member disposed within the outer pipe member; and means for releasably connecting the inner pipe member and the outer pipe member in fixed axial relationship under force loads applied in use during a drilling operation while enabling relative rotary movement between the inner pipe member and the outer pipe member during a rotary drilling operation to relieve torsional stress thereon, and for permitting the removal of the inner pipe member from the outer pipe member by relative axial displacement therebetween caused by application to the inner pipe member of only an axially directed force load in excess of the axially directed force loads applied to the inner pipe member in use during a normal drilling operation.