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:
Sep. 16, 1997
Filed:
Jun. 13, 1996
Sanjay Mahasukhlal Shah, Rochester Hills, MI (US);
Michael Harry Lovell, Leonard, MI (US);
Thomas James Malone, Shelby Township, Macomb County, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A method and apparatus for piercing a pair of aligned holes through both sides of a tube combined with the process of hydroforming the tube to final shape. After the tube is expanded and internally pressurized between upper and lower dies, a punch is driven forcefully through a cross passage in the die and through both walls of the tube, one after the other. The end of the punch is bored out sufficiently to leave a sharp edge that cuts a first slug, and the first slug is wedged into the end of the punch. The opposed wall of the tube is backed by a female die button with a cylindrical cutting edge concentric to, and equal in diameter to, the end of the punch. The end of the punch enters the die button to cleanly shear out a second hole, pushing a stack of two slugs into the die button. A pressure feed orifice properly located enters the still pressurized tube at this point, feeding positive pressure to the punch bore to blow the slugs off and out of the die button.