Cavity forming press

Claim 1

A press stand for shaping a sheet blank by pressing it against a forming tool, said press stand comprising a first press table which provides a support surface, a rigid ring located on said support surface, said rigid ring having an inner surface and a flat end surface remote from said first press table, said flat end surface defining an imaginary plane, a bottom plate located within said rigid ring and resting on said support surface of said first press table, a cup-shaped container located within said rigid ring in spaced fashion from both the inner surface of said rigid ring and from said bottom plate, said cup-shaped container containing said forming tool and having a flat end surface remote from said first press table, an elastic material filling the space between said cup-shaped container and both the inner surface of said cylindrical ring and said bottom plate, said elastic material providing a flat end surface remote from said first press table and located in said imaginary plane, an annular cylinder which is movable towards and away from said first press table, said annular cylinder including a flange which is abuttable against the flat end surface of said cylindrical ring, said flange supporting a flexible diaphragm, and piston means within said annular cylinder which, together with said flexible diaphragm and said annular cylinder provides a closed space, said piston means including a channel for the supply of pressure medium to said closed space for moving said flexible diaphragm against a sheet blank positioned on the end surface of said cup-shaped container and causing said sheet blank to bend against the forming tool within said cup-shaped container, said elastic material propagating the pressure applied thereagainst by said cup-shaped container in all directions.