Press control system

Claim 2

In a press of the type which includes a floating platen and a press bed: fluid pressure means for offering opposition to displacement of the platen toward the bed as a function of the degree of displacement of the platen toward the bed; said fluid pressure means comprising a hydraulic cylinder including a piston mounted for reciprocation in the cylinder to alter the volume of its hydraulic cavity; and said fluid pressure means further including a spring arranged to urge said piston in a direction to reduce the volume of said cavity and means for selectively altering the degree in which said piston is urged in said direction by said spring.

Claim 3

The apparatus defined in claim 1 in which said fluid pressure means comprises at least two such hydraulic cylinders and which further comprises means for causing one of said two hydraulic cylinders to offer greater opposition to displacement of the platen toward the bed than is offered by the other of said two hydraulic cylinders at any given degree of separation of said floating platen and said bed.

Claim 4

The invention defined in claim 2 which comprises a pair of accumulators each having a variable volume and a spring arranged to apply force in a direction to reduce the volume of its respective accumulator; means for connecting the cavity of each of said two hydraulic cylinders to a respectively associated one of said accumulators such as to permit fluid flow between each accumulator and the cavity of its associated hydraulic cylinder; and means for selectively adjusting the force applied by at least one of said springs.

Claim 5

The apparatus defined in claim 1 which further comprises a variable volume accumulator; means for interconnecting the cavity of the cylinder with the accumulator such as to permit fluid flow between the cavity and the accumulator.

Claim 6

The apparatus defined in claim 4 which further comprises resilient means for urging a reduction in the volume of said accumulator in selected degree.

Claim 7

A pressure control apparatus for a press of the kind in which a ram is moved toward and away from a platen which is itself movable toward a fixed bed, comprising: initial displacement adjusting means responsive to a hydraulic pressure for altering the separation of platen and bed independent of ram movement; movement opposing means responsive to the application of force to said platen as an incident to displacement of the ram which force tends to displace the platen toward the bed for opposing such displacement of the platen in proportion to the degree of separation of said platen and said bed; means for detecting that said platen has been moved to the first one and the second one of at least two positions relative to the said bed; and means for interrupting displacement of said platen if the force opposing movement of the platen falls without a first range of forces when said platen occupies said first one of said positions and for interrupting displacement of said platen if the force opposing movement of the platen falls without a second range of forces when the platen occupies said second one of said positions.

Claim 8

A pressure control apparatus for a press of the kind in which a ram is moved toward and away from a platen which is itself movable toward a fixed bed, comprising: initial displacement adjusting means responsive to a hydraulic pressure for altering the separation of platen and bed independent of ram movement; movement opposing means responsive to the application of force to said platen as an incident to displacement of the ram which force tends to displace the platen toward the bed for opposing such displacement of the platen in proportion to the degree of separation of said platen and said bed; means for detecting that said platen has been moved to the first one and the second one of at least two positions relative to the said bed; and means for interrupting displacement of said platen if the force opposing movement of the platen falls without a first range of forces when said platen occupies said first one of said positions and for interrupting displacement of said platen if the force opposing movement of the platen falls without a second range of forces when the platen occupies said second one of said positions.

Claim 9

The apparatus defined in claim 6 in which said movement opposing means operates to develop an hydraulic pressure proportional to the degree of opposition to such movement; and which comprises means for measuring said hydraulic pressure when the platen occupies each of said first and said second positions; and in which said means for interrupting movement of said ram is responsive to said means for measuring said hydraulic pressure.

Claim 10

The apparatus defined in claim 7 which further comprises means for relieving said hydraulic pressure in the event that the pressure falls above said first or second force range when said platen occupies said first and said second position, respectively.

Claim 11

In a press of the kind that includes a floating platen and a bed: fluid pressure means for opposing displacement of the platen toward the bed in a degree which increases with the degree of such displacement; an elastic element whose renitence is adjustable; means for selectively adjusting the renitence exhibited by said elastomeric element; and means for altering the degree in which said fluid pressure means opposes displacement of the platen toward the bed at different degrees of such displacement as an incident to selective adjustment of the degree of renitence exhibited by said elastic element.

Claim 12

In a press of the kind that includes a floating platen and a bed: fluid pressure means for opposing displacement of the platen toward the bed in a degree which increases with the degree of such displacement; an elastic element whose renitence is adjustable; means for selectively adjusting the renitence exhibited by said elastomeric element; and means for altering the degree in which said fluid pressure means opposes displacement of the platen toward the bed at different degrees of such displacement as an incident to selective adjustment of the degree of renitence exhibited by said elastic element.

Claim 13

The apparatus defined in claim 9 in which said fluid pressure means comprises a cylinder and in which elastic element comprises an accumulator, each of said cylinder and accumulator having a variable volume cavity for hydraulic fluid; and which apparatus further comprises a flowpath for hydraulic fluid interconnecting the cavity of the cylinder and the cavity of the accumulator.

Claim 14

The apparatus defined in claim 10 in which said accumulator includes means in the form of a spring effective to exert pressure to alter the volume of the cavity of the accumulator; and which further comprises means for selectively altering said pressure exerted by said spring.

Claim 15

The apparatus defined in claim 10 in which said cylinder comprises a piston and means in the form of a spring for applying forces to urge a reduction in the volume of the fluid cavity in said cylinder.