Patent ID: 8113111
Filing Date: 2012-02-14
Classification: B21D,B30B,Y10T

Abstract:
1. A device for preventing a tool from breaking during fine blanking and/or forming operations in a press, the tool comprising an upper and lower part, the device being positioned above a ram provided in the press, the ram carrying out a stroke movement along a stroke axis, the device positioned above the ram, the upper part of the tool connected to the device at a touch table provided on a ram side of the device, the device comprising: a fine blanking head, the fine blanking head including a head piece frame holding a main cylinder, the main cylinder retaining a V-shaped projection piston aligned on the stroke axis, V-shaped projection pins that are coaxially arranged, with respect to the stroke axis, the V-shaped projection pins being axially guided by a main plate covering the main cylinder on a ram side thereof, the V-shaped projection pins being supported on a V-shaped projection pressure plate, wherein the main cylinder is provided with a pressure-tight seal at a top side of the main cylinder by a V-shaped projection cover; a hydraulic system for generating pressure in the main cylinder, the hydraulic system being in connection with the fine blanking head and a source of pressurized fluid, the hydraulic system provided with valves under the control and operation of a computer, whereby the computer, through valve operation, controls and regulates the flow of pressurized fluid; the main cylinder further retaining a touch piston positioned between the V-shaped projection piston and V-shaped projection pins, the V-shaped projection piston, the V-shaped projection pins, and the V-shaped projection pressure plate being in an axially movable arrangement with respect to each other in alignment along the stroke axis; first, second, and third pressure rooms provided in the main cylinder, each respectively having a connection to the hydraulic system through, respectively, first, second, and third connections provided in the V-shaped projection cover; a touch table fixedly attached in suspension to the main plate by fixing means, the fixing means providing a gap having a predetermined gap dimension between the main plate and touch table, the predetermined gap dimension being detected by a sensor, the touch table being provided with means for attaching the upper part of the tool; and whereby, during operation of the press, in the event of a change in the predetermined gap dimension, the sensor transmits a signal to the computer, and in processing the signal, the computer stops the operation of the press to protect the upper part of the tool against damage.