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:
Jun. 14, 1994
Filed:
Feb. 10, 1992
Robert R Hellman, Sr, Oxford, CT (US);
Other;
Abstract
In a preferred embodiment, a method and apparatus for hydroforming thin-wall metal corrugated tubing which include first preforming the corrugated tubing in a conventional hydroforming operation of the type in which each convolution is formed separately. Semi-resilient spacers are then inserted between the sides of adjacent internal convolutions, while non-resilient washers are inserted between the sides of adjacent external convolutions. The corrugated tubing with the inserted spacers and washers is then highly compressed to the total thickness of the individual elements, with the spacers and washers controlling the radii formed at the crests and troughs of the convolutions. The resulting corrugated tubing has trough and crest radii on the order of 11/2 to 2 metal thicknesses, has an extension/compression ratio of 4 or greater, and can be compressed nearly flat. The sides of the convolutions are given a sine wave shape in cross-section to distribute stresses, so that they are not concentrated at the relatively sharp radii, and to eliminate noise when the corrugated tubing is flexed.