Apparatus for deforming sheet metal blanks by fluid pressure

• US 3,890,819 A
• Filed: 07/25/1973
• Issued: 06/24/1975
• Est. Priority Date: 07/25/1972
• Status: Expired due to Term

• Current Assignee: Bruno Deluca
• Original Assignee: Bruno Deluca
• Inventors: DeLuca, Bruno
• Primary Examiner(s): Herbst, Richard J.
• Application Number:
  US05/382,506
• Time in Patent Office: 699 Days
• Field of Search: 72/54,57,60 29/421
• US Class Current: 72/57
• CPC Class Codes: B21D 24/08 Pneumatically or hydraulically loaded blank holders
• CPC Class Codes: B21D 26/02 by applying fluid pressure
• CPC Class Codes: B21D 26/025 Means for controlling the clamping or opening of the moulds
• CPC Class Codes: Y10T 29/49805 Shaping by direct application of fluent pressure

Abstract

A sheet metal blank is clamped between opposed annular members and deformed in its central area by fluid pressure applied thereto. The clamping members are urged together by the same fluid pressure; and to this end, one of the clamping members is mushroom-shaped with the head of the mushroom comprising a piston urged in a clamping direction by fluid pressure applied by an annular cylinder chamber that communicates with a central chamber whose fluid deforms the blank. In this way, the annular marginal portions of the blank are tightly gripped and only the central exposed portion of the blank is deformed.

Claims

1. Apparatus for deforming only a central portion of sheet material by fluid pressure, comprising means to clamp a peripherial portion of said material entirely about said central portion while leaving said central portion exposed, means mounting said clamping means for free and unimpeded movement toward said material, meAns to apply the pressure of a fluid under pressure to said exposed central portion of said material to deform only said central portion of said material, and means to apply said pressure also to said clamping means so that the force with which said peripheral portion is clamped by said clamping means varies directly as said pressure over the entire range of said pressure thereby to maintain said peripheral portion against substantial radially inward movement over said entire range of pressure.

2. Apparatus as claimed in claim 1, said clamping means comprising an annular member, means mounting said annular member for movement toward and away from the material to be clamped, and means for applying said fluid to said material centrally of said annular member.

3. Apparatus as claimed in claim 2, and an annular die on the side of said material opposite said clamping member, said annular die having a central opening for receiving material deformed by said pressure.

4. Apparatus as claimed in claim 1, and a hollow body within which said clamping means is mounted for sliding movement toward and away from said material, said clamping means and said hollow body defining between them an annular cylinder chamber, and means for applying said pressure within said cylinder chamber to urge said clamping means in the direction of said material.

5. Apparatus as claimed in claim 4, said clamping means having a central opening through which said fluid is applied to said material, said applying means comprising at least one opening through said clamping means communicating between said annular chamber and said central opening.

6. Apparatus as claimed in claim 4, the area of said annular cylinder chamber in a plane perpendicular to the axis thereof being greater than the area of said material exposed to said pressure.

7. Apparatus as claimed in claim 4, said clamping member having a head thereon that defines said annular chamber between said head and the bottom of a cup-shaped recess within said body.