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. 27, 1976
Filed:
Sep. 04, 1973
John W Berg, Sunnyvale, CA (US);
Other;
Abstract
A means of and method of forming sheet metal by use of fluid pressure wherein an initially flat sheet metal work piece is placed on a backing plate with its margins clamped between the plate and a peripheral clamping ring. The clamping ring is clamped against the margin of the work piece by a plurality of fluid operated clamping units. the side of the work piece opposite from the backing plate and within the clamping ring is free to expand or distend without restraint except that provided by the metal comprising the work piece itself. Pressure fluid is introduced between the metal work piece and its backing plate to cause the work piece to distend away from the backing plate. A set of freely movable feeler strips engage the edge of the work piece at spaced points. The feeler strips control sensing units which, in turn, control the pressure exerted by the clamping units so as to permit predetermined slippage of the margin of the work piece with respect to the clamping rings. If the dimensions of the work piece are critical and the undulated zone of the work piece is within the boundaries of the finished product, the work piece is placed on the same or second backing plate so that the margins of the work piece are between the backing plate and a clamping ring of predetermined increased internal dimension to clear the periphery of the distended portion of the work piece. A forming die overlies and clears the distended work piece and is joined at its periphery to the clamping ring. After removing air from the distended work piece, pressure fluid is applied to further distend the work piece, eliminating the undulations and presses the work piece into conformity with the die while its margin is clamped against slippage. One embodiment of the means and method includes a valve sensitive to the pressure of the pressure fluid for varying the pressure in the clamp units in proportion to the change in pressure required to form the work piece as the work piece changes its shape. Another embodiment utilizes a deformable membrane, which may be a second work piece, in place of the backing plate. A further embodiment involves the sandwiching of the part to be formed between sheets of expendable sheets. A still further embodiment includes the use of pressure fluid, heated or cooled to temperatures at which the forming of the metal is enhanced.