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. 02, 1999
Filed:
Jun. 02, 1998
Applicant:
Inventors:
Frederick Irvin Saunders, Sterling Heights, MI (US);
Paul Edward Krajewski, Sterling Heights, MI (US);
Edward Frank Ryntz, Warren, MI (US);
James Gregory Schroth, Troy, MI (US);
Assignee:
General Motors Corporation, Detroit, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B21D / ;
U.S. Cl.
CPC ...
72 57 ; 72 60 ; 294211 ;
Abstract
A method is disclosed for stretching sheet blanks, especially superplastic sheets, by differential gas pressure into conformity with a female die surface without encountering excessive thinning or tearing of the sheet. The warmed SPF sheet is draped over a preformed surface to draw more of the sheet material into the die cavity before the edges of the sheet are fixedly clamped whereby the additional formable material is used in forming the product, thereby reducing thinning and tears.