Apparatus and method for stripping away/pushing out a punched grid/internally formed part and ejecting a blanked part in a precision blanking press

A hydraulically actuated apparatus configured to cooperate, as part of a fine blanking press, with a punch die comprised of a punch, a hole punch, a die block and a knife-edged ring block comprising a knife-edged ring, the punch having an axial throughhole and an annular distal end, the hole punch being configured to be received in the throughhole at the distal end of the punch, the punch die being configured to blank the workpiece to form a blanked part from an internal part of the workpiece and a part in the form of a grid, the hydraulically actuated apparatus comprising a top and a base, a knife-edged ring-actuating cylinder disposed in the top, a knife-edged ring-actuating piston received in the cylinder disposed in the top and configured to apply a force that acts on first pins, the first pins being guided in said cylinder and configured to act on the knife-edged ring block, said knife-edged ring-actuating cylinder including a pressure chamber configured to be pressurized by a hydraulic fluid, a main cylinder disposed in the base, a main piston with a counterstay piston actuated by a pressure chamber communicating only with the counterstay piston, the counterstay piston being configured to act on second pins, the second pins being guided in said base and configured to apply a force to the clamped workpiece counter to a punching force applied to the clamped workpiece by the punch, the main cylinder comprising pressure chambers configured to be pressurized by a hydraulic fluid to actuate the main piston, said main piston being configured to make a stroke in a direction of a stroke axis and thereby to blank the workpiece to form a grid retained on the die block and an interior part of the workpiece punched out by the hole punch and retained in the punch, and a hydraulic system for supplying the pressure chambers with the hydraulic fluid, a central control system configured to adjust the fluid to a predetermined working pressure, wherein the knife-edged ring-actuating piston and cylinder and a stripping/pushing piston and cylinder are disposed in the top as a first unit and the counterstay piston and an ejecting piston are disposed as a second unit in the base, the stripping/pushing piston is configured to apply a force to strip the grid from the die block and the ejection piston is configured to apply a force to eject the punched out part of the workpiece out of the punch, the stripping/pushing piston comprises a piston rod extending through and coaxially with the knife-edged ring-actuating piston, a pusher block is formed at a distal end of the piston rod abutting a surface of a distal end of the knife-edged ring-actuating piston, the pressure chamber in the knife-edged ring-actuating cylinder operatively communicates only with the knife-edged ring-actuating piston, the stripping/pushing cylinder is situated atop the knife-edged ring-actuating cylinder, at least one respective pressure chamber situated in the stripping/pushing cylinder operatively communicates only with the stripping/pushing piston and a respective pressure chamber operatively communicates only with the ejecting piston, the pressure chamber operatively communicating with the stripping/pushing piston and the pressure chamber respectively communicating with the ejecting piston are in mutual connection by way of a first controllable hydraulic circuit of a hydraulic system, and the respective pressure chambers operatively communicating with the knife-edged ring-actuating piston and with the counterstay piston respectively are in mutual connection by way of a second controllable hydraulic circuit wherein the first and the second controllable hydraulic circuits are configured to be controlled independently of one another and wherein the main piston is provided with a channel having a first section perpendicular to and a second section parallel to the stroke axis for pressurizing the pressure chamber which communicates operatively with the counterstay piston with hydraulic fluid of redetermined pressure from the second hydraulic circuit of the hydraulic system.