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. 24, 1976
Filed:
Jan. 21, 1975
James H Casey, Roseville, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A device used during fusion butt-welding between the ends of tubes to form a backing for the weld inside the tubes. The device comprises a thin flexible metal support strip having end portions which are overlapped to provide an arcuate outer peripheral surface, means guiding the overlapping end portions for relative longitudinal sliding movement to change the peripheral circumference of the support strip, and means for biasing the end portions in a direction to increase the peripheral circumference of the device. For use, the circumference of the support strip is decreased in opposition to the biasing means, and a backing strip of refractory material is secured on the periphery of the support strip. Next the device is positioned with the backing strip adjacent the inner surfaces of and bridging the ends of the tubes to be welded. The device is activated so that the biasing for the support strip will press the backing strip into engagement with the tubes, and the tubes are ready for welding.