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:
Apr. 25, 2000
Filed:
Sep. 16, 1997
Zexel Corporation, Tokyo, JP;
Abstract
When forming a circular tube-shaped header pipe by rolling a plate material, surfaces extending at a right angle to the internal and external surfaces of the plate material are formed at the two side edges extending in the lengthwise direction, and the plate material is rolled in such a manner that the two side edges face opposite each other while setting the two side edges in a non-contact state. In this process, the gap between the two side edges is set at or less than 0.3 mm. In order to manufacture this header pipe, a plate material that has been cut to a specific length is trimmed in the direction of its short side to achieve a specific dimension and also at a right angle to the front and rear surfaces of the plate material. After a piping insertion hole is formed, the entirety of the plate material is rolled so that its cross section achieves a U-shape. A plurality of tube insertion holes are formed in this state and then, with only an upper die and a lower die, the two side edges of the plate material are rolled in a circular tube shape so that they face opposite each other. Any level misalignment between the side edge portions that face opposite each other can be prevented, and defective brazing is eliminated.