Method and apparatus for making deep drawn metal shells

Claim 2

Apparatus for making a comparatively deep metal shell comprising: a stationary tubular mandrel having an open-ended passage extending axially therethrough; means for positioning a substantially flat piece of sheet metal adjacent an end of said mandrel; a die-supporting plate movable toward and away from said end of said mandrel; annular die means carried by and movable with said plate into telescoping relation to said end of said mandrel for drawing a piece of sheet metal into a cup shaped workpiece over said end of said mandrel; spring means connected with said die-supporting plate and arranged to urge said plate toward said end of said mandrel to bring said die means into engagement with a piece of metal positioned adjacent said end of said mandrel; an annular ironing die positioned in substantial axial alignment with the opposite end of said mandrel; and a punch member movable axially and successively in a single, continuous stroke through said die means, said mandrel and said ironing die and operable to evert, redraw and iron the workpiece to form therefrom an elongated metal shell.

Claim 3

Apparatus according to claim 1, wherein said die means includes a blanking die operable in response to forces exerted by said spring means to cut a piece of sheet metal positioned adjacent said first-named end of said mandrel prior to drawing it over said end of said mandrel; and wherein said apparatus includes a first fluid pressure-operated means con-nected with said die-supporting plate and operable to move said plate toward and away from said first-named end of said mandrel, and a second fluid pressure-operated means for moving said punch member.

Claim 4

In an hydraulic press for making elongated metal shells; a supporting frame; at least three bolsters stationarily secured in relatively spaced apart relation to said frame and including a first end bolster, an intermediate bolster and an opposite end bolster, said bolsters being formed with relatively aligned openings defining a working axis for the press; a plurality of strain rods interconnecting said bolsters and disposed in radially offset, parallel relation to the working axis of the press; a tubular mandrel stationarily carried by said intermediate bolster in coaxial relation to the working axis of the press; a die-carrying plate movably carried by said strain rods between said first end bolster and said intermediate bolster; die means carried by said die-carrying plate in coaxial relation to the working axis of the press and movable with said plate into telescop-ing relation to one end of said mandrel, said die means being operable to draw an initially flat piece of sheet metal over said end of said mandrel to form it into a cup-shaped workpiece; first hydraulic ram means connected with said first end bolster and with said die-carrying plate and operable to move said die means into telescoping relation to said mandrel; an ironing die carried by said opposite end bolster and having a central opening coaxial with the working axis of the press; a punch member movable along the working axis of the press and movable successively through said die means, said mandrel and said ironing die to evert, redraw and iron said workpiece into an elongated shell; second hydraulic ram means connected with said first end bolster and with said punch member and operable to reciprocate said punch member through said die means, said mandrel and said ironing die; and stripping means carried by said opposite end bolster and operable to strip a finished elongated shell from said punch member following movement thereof through said ironing die.

Claim 5

In an hydraulic press for making elongated metal shells; a supporting frame; at least three bolsters stationarily secured in relatively spaced apart relation to said frame and including a first end bolster, an intermediate bolster and an opposite end bolster, said bolsters being formed with relatively aligned openings defining a working axis for the press; a plurality of strain rods interconnecting said bolsters and disposed in radially offset, parallel relation to the working axis of the press; a tubular mandrel stationarily carried by said intermediate bolster in coaxial relation to the working axis of the press; a die-carrying plate movably carried by said strain rods between said first end bolster and said intermediate bolster; die means carried by said die-carrying plate in coaxial relation to the working axis of the press and movable with said plate into telescop-ing relation to one end of said mandrel, said die means being operable to draw an initially flat piece of sheet metal over said end of said mandrel to form it into a cup-shaped workpiece; first hydraulic ram means connected with said first end bolster and with said die-carrying plate and operable to move said die means into telescoping relation to said mandrel; an ironing die carried by said opposite end bolster and having a central opening coaxial with the working axis of the press; a punch member movable along the working axis of the press and movable successively through said die means, said mandrel and said ironing die to evert, redraw and iron said workpiece into an elongated shell; second hydraulic ram means connected with said first end bolster and with said punch member and operable to reciprocate said punch member through said die means, said mandrel and said ironing die; and stripping means carried by said opposite end bolster and operable to strip a finished elongated shell from said punch member following movement thereof through said ironing die.