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. 17, 1993
Filed:
Apr. 24, 1992
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
A piercing die including a punch and a die cooperating with each other to effect a piercing operation on a metallic workpiece sheet, the punch having an outer peripheral edge having a closed profile at a working end thereof. The outer peripheral edge of the punch has a first and a second chamfered portion which are formed such that the amount of chamfer of the first chamfered portion is larger than that of the second chamfered portion. The first and second chamfered portions are formed along large-curvature and small-curvature portions of the closed profile of the punch, respectively, and/or along acute and obtuse outer peripheral portions of the punch whose working end face is inclined with respect to the direction perpendicular to the piercing direction. A piercing method using the punch and die is also included.