Process and press with a controlled pressure system

A press for forming a plurality of shaped articles from sheet material, said press comprising:

• (a) a frame;
• (b) a plurality of pairs of first and second complementary dies, each said pair cooperating to form one said article;
• (c) ram means supported by said frame for axial movement, said ram means carrying a plurality of said first dies for movement together;
• (d) cam means for reciprocally moving said ram means between a first position where said pairs of first and second dies are spaced and a second position where said pairs of first and second dies are mated, said cam means including a dwell period when said ram means is in said second position;
• (e) bolster means supporting each said second die for independent axial movement between upper and lower limits, each said bolster means being axially spaced from its upper limit when said ram means is in said said second position;
• (f) low pressure power means for normally biasing each said bolster means toward its upper limit under a predetermined first pressure;
• and
• (g) high pressure power means responsive to said cam means for biasing each said bolster means towards its upper limit under a predetermined second hydraulic pressure during said dwell period, said second pressure being greater than said first pressure.

A method of forming a shaped article for sheet material, said method comprising:

• (a) providing a first die for reciprocal axial movement between first and second positions;
• (b) providing a second die, complementary and axially opposed to said first die for axial movement between upper and lower limits;
• (c) normally applying a first predetermined pressure to said second die to bias said second die towards said upper limits;
• (d) disposing said sheet material between said first and second dies;
• (e) axially moving said first die from said first position spaced from said second die to said second position mated with said second die by a force sufficient to axially move said second die from its upper limit when said first die achieves its second position;
• (f) maintaining said first die in said second position for a predetermined period;
• (g) while said first die is in said second position, applying a second predetermined hydraulic pressure to said second die to bias said second die toward said upper limit, said second pressure being greater than said first pressure;
• (h) removing said second predetermined pressure and axially moving said first die from said second position to said first position;
• and
• (i) removing said shaped article.

A press for shaping a workpiece into an article said press comprising:

• (a) first and second axially opposed dies cooperatively disposed to press said workpiece each said die being disposed for movement on an axial path between respective upper and lower limits, the lower limit of said first die being below the upper limit of said second die, said dies at their respective upper limits being axially spaced a distance sufficient to permit placement of said workpiece therebetween;
• (b) means for reciprocally moving said first die between its upper and lower limits, said moving means including means for maintaining said first die proximate its lower limit for a predetermined period;
• (c) resistance means biasing said second die under a controlled, predetermined first pressure for yieldingly resisting movement of said first die toward its lower limit, said first pressure being sufficient to shape said workpiece between said dies and to place said dies in full operative engagement proximate the lower limit of said die;
• (d) pressing means biasing said second die under a controlled, predetermined second pressure in opposition to said first die during said predetermined period for forming said shaped workpiece between said dies;
• (e) means for selectively adjusting the magnitude of said first and second pressures;
• and
• (f) control means responsive to said moving means for normally actuating said resistance means and for actuating said pressing means during said predetermined period.

A press for shaping a plurality of workpieces into articles, said press comprising:

• (a) a frame;
• (b) a plurality of pairs of first and second axially opposed dies, each pair being cooperatively disposed to independently press said workpieces, each die of each said pair being disposed for movement on a respective axial path between respective upper and lower limits, the lower limits of said first dies being below the upper limits of said second dies, said dies at their respective upper limits being axially spaced a distance sufficient to permit placement of said workpieces there-between;
• (c) means for reciprocally moving said first dies between their respective upper and lower limits, said moving means including means for maintaining said first dies proximate their respective lower limits for a predetermined period;
• (d) resistance means independently biasing each said second die under a controlled, predetermined first pressure for yieldingly resisting movement of said first dies toward their lower respective limits, said first pressure being sufficient to shape said workpieces between said respective die pairs and to place said die pairs in full operative engagement proximate the lower limits of said first dies;
• (e) pressing means independently biasing each said second die under a controlled predetermined second pressure in opposition to its respective first die during said predetermined period for forming said shaped articles between said respective die pairs;
• (f) means for selectively adjusting the magnitude of said first and second pressures;
• and
• (g) control means responsive to said moving means for normally actuating each said resistance means and for actuating each said pressing means during said predetermined period.

In a press for simultaneously forming a plurality of shaped articles from a blank of sheet material, said press including a frame supporting a plurality of pairs of axially opposed first and second dies, each said first die being axially moveable between a first position spaced from and a second position fully mated with its respective second die, the press also including means for simultaneously cyclicly moving a plurality of said first dies between their first and second positions and for maintaining said first dies in said second positions for a predetermined period, the improvement comprising:

• (a) means for separately supporting each said second die in said frame for independent axial movement between upper and lower limits;
• (b) means for generating a uniform force between the first and second dies of each said pair, said generating means including;
• (1) a plurality of hydraulic cylinders, one of said cylinders operatively engaging each said second die to bias said second die toward it respective first die;
• and
• (2) control means responsive to said moving means for normally conducting hydraulic fluid at a first pressure to each said cylinder and for conducting hydraulic fluid at a greater, second pressure to each said cylinder only during said predetermined period;
• and
• (c) means for selectively adjusting the magnitude of said first and second pressures.