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:
Jan. 10, 1989
Filed:
Sep. 08, 1987
William A Mueller, Fairhaven, MI (US);
Wolfgang Hoffmann, Grosse Pointe Woods, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An accumulator system for establishing a clamping force on dies in a closed die forging device. The accumulator system includes an accumulator having a differential piston and a free piston. The small end of the differential piston forms a wall of the accumulator oil chamber hydraulically connected to variable volume oil chambers behind the dies. The big end of the differential piston and one side of the free piston form a low pressure gas chamber of the accumulator. The other side of the free piston forms a wall of a high pressure gas chamber of the accumulator. As the dies of the forging apparatus close, oil in the chambers behind the dies moves the differential piston against only the gas pressure in the low pressure gas chamber so that closure is essentially without impact. Just before the onset of forging, the big end of the differential piston engages the free piston so that thereafter the two move as a unit against the higher gas pressure in the high pressure gas chamber of the accumulator whereby the clamping force on the dies increases at a higher rate.