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:
Aug. 24, 1993
Filed:
Feb. 19, 1992
Toshiki Miyazawa, Tokyo, JP;
Hidaka Seiki Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention provides a method of manufacturing fins for heat exchangers, wherein a collared through-hole of a prescribed height can be easily formed while using volatile oils as machining oil, even if the material of the metal plate is thinner and harder than conventionally used. To achieve the object, the method has following steps: forming a conical section in a metal plate, wherein the base diameter of the conical section is greater than the diameter of the collared through-hole to be formed, and the thickness of the top section of the conical section is thinner than other parts of the metal plate; transforming the conical section into a truncated conical section or a columnar section by extending and flattening the top section of the conical section; forming a through-hole and a projected section about the edge of the through-hole, by boring and burring the truncated conical section or columnar section; and ironing the projected section with a punch, whose outer diameter is equal to the inner diameter of the collared through-hole to be formed, and a die, whose inner diameter is equal to the outer diameter of the collared through-hole to be formed.