An apparatus for the controlled return of the stems in cylinders of the types that can be applied to a press for stamping sheet metal, comprising: at least one fluid-operated cylinder), at least one hydraulic accumulator which is fluidically connected to the at least one cylinder by means of a hydraulic circuit which comprises: a duct for the discharge of the working fluid from the at least one cylinder and a duct/branch for the intake of the working fluid in the hydraulic accumulator, a duct for loading the working fluid in the at least one cylinder and at duct/branch for the output of the working fluid from the hydraulic accumulator.

An apparatus for the controlled return of the stems in cylinders of the types that can be applied to a press for stamping sheet metal, comprising: at least one fluid-operated cylinder), at least one hydraulic accumulator which is fluidically connected to the at least one cylinder by means of a hydraulic circuit which comprises: a duct for the discharge of the working fluid from the at least one cylinder and a duct/branch for the intake of the working fluid in the hydraulic accumulator, a duct for loading the working fluid in the at least one cylinder and at duct/branch for the output of the working fluid from the hydraulic accumulator.

A controllable force cushion device that can be programmed to provide a variable and/or pulsating force that can be used in any application where force control is desirable. The frequency of the pulsation can be adjusted to suit different applications and/or circumstances (e.g., forming of sheet metals in die applications, etc.). The cushion can comprise one or more manifolds containing hydraulic cylinders that can be compressed during operation pushing fluid through a proportional relief valve that can be controlled by a motion control device, thereby creating a desired force. Material (e.g., sheet metal, etc.) flow can be controlled by using a gap control method. In use, the variable pulsating, gap control, auto-learning press cushion device of the present invention can optionally be mounted to the underside of a press bolster and can be used in conjunction with a stamping press.

A controllable force cushion device that can be programmed to provide a variable and/or pulsating force that can be used in any application where force control is desirable. The frequency of the pulsation can be adjusted to suit different applications and/or circumstances (e.g., forming of sheet metals in die applications, etc.). The cushion can comprise one or more manifolds containing hydraulic cylinders that can be compressed during operation pushing fluid through a proportional relief valve that can be controlled by a motion control device, thereby creating a desired force. Material (e.g., sheet metal, etc.) flow can be controlled by using a gap control method. In use, the variable pulsating, gap control, auto-learning press cushion device of the present invention can optionally be mounted to the underside of a press bolster and can be used in conjunction with a stamping press.

A die cushion device of a press machine includes a hydraulic cylinder that supports a cushion pad and generates die cushion force when a slide of the press machine descends, an orifice and a hydraulic pump/motor that are connected to each other in in parallel between a lower chamber of the hydraulic cylinder and a tank, a servo motor connected to a rotating shaft of the hydraulic pump/motor, and a control unit that controls torque of the servo motor to control the die cushion force, wherein a rotation direction of the servo motor switches from a first rotation direction in which the hydraulic pump/motor serves as a hydraulic motor to a second rotation direction in which the hydraulic pump/motor serves as a hydraulic pump, during generation of the die cushion force.

A die cushion device of a press machine includes a hydraulic cylinder that supports a cushion pad and generates die cushion force when a slide of the press machine descends, an orifice and a hydraulic pump/motor that are connected to each other in in parallel between a lower chamber of the hydraulic cylinder and a tank, a servo motor connected to a rotating shaft of the hydraulic pump/motor, and a control unit that controls torque of the servo motor to control the die cushion force, wherein a rotation direction of the servo motor switches from a first rotation direction in which the hydraulic pump/motor serves as a hydraulic motor to a second rotation direction in which the hydraulic pump/motor serves as a hydraulic pump, during generation of the die cushion force.

A press system providing excellent energy efficiency for a whole press system and capable of achieving low prices is provided. A die cushion apparatus constituting a press system supports a cushion pad, includes a hydraulic cylinder which generates a die cushion load on the cushion pad when a slide of a press machine descends, the press machine includes a hydraulic cylinder which generates part of a press load on the slide when the slide descends. The pressure generation chamber of the hydraulic cylinder for generating a die cushion load and the pressure generation chamber of the hydraulic cylinder for generating part of the press load can communicate with each other via pipes and a first logic valve for a period during which the die cushion load acts.

A press system providing excellent energy efficiency for a whole press system and capable of achieving low prices is provided. A die cushion apparatus constituting a press system supports a cushion pad, includes a hydraulic cylinder which generates a die cushion load on the cushion pad when a slide of a press machine descends, the press machine includes a hydraulic cylinder which generates part of a press load on the slide when the slide descends. The pressure generation chamber of the hydraulic cylinder for generating a die cushion load and the pressure generation chamber of the hydraulic cylinder for generating part of the press load can communicate with each other via pipes and a first logic valve for a period during which the die cushion load acts.

A method for operating a forming press which includes a plurality of press components and a plurality of tool components. The forming press has at least one force sensor and at least one force actuator, each arranged in a press and/or tool component. A forming simulation is carried out, which takes into consideration an elastic behavior of the press and/or tool components. Target values of forces acting on at least one press and/or tool component are determined by the forming simulation. A forming process is carried out by the forming press. During the forming process, actual values of forces acting on the press and/or tool components are measured by the force sensor and the force actuator is actuated via a control loop such that the actual values correspond to the target values from the forming simulation.

A method for operating a forming press which includes a plurality of press components and a plurality of tool components. The forming press has at least one force sensor and at least one force actuator, each arranged in a press and/or tool component. A forming simulation is carried out, which takes into consideration an elastic behavior of the press and/or tool components. Target values of forces acting on at least one press and/or tool component are determined by the forming simulation. A forming process is carried out by the forming press. During the forming process, actual values of forces acting on the press and/or tool components are measured by the force sensor and the force actuator is actuated via a control loop such that the actual values correspond to the target values from the forming simulation.