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:
Jan. 24, 1978
Filed:
Jan. 21, 1977
Floyd W Becker, Calgary, CA;
Drill Systems Inc., Calgary, CA;
Abstract
The present invention provides a means for mounting the inner pipe within the outer pipe of a double-walled pipe used in reverse-circulation drilling so that torques imparted to the outer pipe will not be imparted to the inner pipe, in order to avoid failure of the inner pipe. The inner pipe has a bushing slidably received thereon at each end, the bushing being affixed, as by a plurality of welded circumferentially spaced ribs, to the inner wall of the outer pipe so that the inner pipe is free to rotate relative to the outer pipe. An annular locating sleeve is received on and welded to the inner pipe adjacent each end of each bushing so that axial, or longitudinal movement of the inner pipe relative to the outer pipe is restrained. Since the inner pipe is free to rotate it will not be affected by excessive torque applied to the outer pipe and, in fact, the double-walled pipe can be given a higher torque rating than it would merit if the inner pipe were non-rotatably fixed to the outer pipe.