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:
Nov. 27, 1979
Filed:
Jan. 11, 1978
Toshihiko Fukushima, Shimoinayoshi, JP;
Kunio Fujie, Tokyo, JP;
Akira Arai, Sakuramura, JP;
Nobukatsu Arai, Ushikumachi, JP;
Kimio Kakizaki, Hitachi, JP;
Hitachi, Ltd., , JP;
Abstract
An apparatus for manufacturing heat transfer tubes for use in evaporators and coolers for freezers, air conditioning units, refrigerators, and the like, with close machining tolerances. It forms cavities, with small openings communicating them with the outside, on the inside of a tube, through three steps of forming a multiplicity of alternate grooves and ribs in parallel on the inner surface of the tube, forming cuts in the concentrically directed crests of the ribs, and then forcing the crests sidewise so that the crest of each rib is bent down onto an intermediate part of the adjacent rib to form a cavity in between.