Die assembly having means for automatically controlling in the angular orientation of the lower die plate members

A system for bending a flat metal stock comprising:

• means for supporting a tool member;
• hinged plate members for supporting said flat metal stock;
• rotatable means secured to and positioned below said hinged plate members for rotating said plate members to a predetermined angular position when a force is applied to said plate members;
• means movable in the vertical direction and coupled to said hinged plate members to apply a force thereto;
• an expandable pressure device having a wall portion in contact with said movable means, a pressure controllable material being enclosed therein, the position of said wall portion being dependent upon the pressure of the material within said container;
• and
• means for controlling the pressure of said material whereby the position of said movable means is controlled to provide the desired angular orientation between said plate members, said tool applying said vertical bending force to said metal stock.

A die for use with a tool for bending flat metal stock comprising:

• means for supporting a pair of pivotable plate members, said pivotal plate members having upper and lower surfaces, the upper surfaces of said plate members adapted to support a piece of flat metal stock;
• means coupled to the lower surfaces of said plate members for converting an essentially vertically force applied to the metal stock to a rotary force applied to said plate members whereby said plate members assume a selected angular orientation with respect to each other;
• means coupled to said plate members for limiting the angular orientation of said plate members to a predetermined value;
• an expandable pressure device coupled to said limiting means, a pressure controllable material being enclosed therein, said expandable pressure device comprising an enclosed container having at least one wall portion, the position of said wall portion being dependent upon the pressure of the material within said container;
• and
• means for controlling the pressure of said material whereby the limit position of said limiting means is selected to provide the desired angular orientation between said plate members.