Hubbewegungseinrichtung in Blechbearbeitungsmaschinen, insbesondere in Aushau- und Nibbelscheren

摘要

1,129,247. Nibbling. PULLMAX A.B. 26 Aug., 1966 [27 Aug., 1965], No. 38344/66. Heading B3W. A high-frequency nibbling or punching machine in which the tool reciprocates includes a toggle mechanism of which one end of a first arm is rotatable about a first pin, adjustably fixed to the machine frame and one end of a second arm of which is rotatable about a second pin directly connected to a tool-holder guided in the frame for movement towards the first pin, the other ends of the first and second arms being pivotably connected to one another by means of a third intermediate pin which has an oscillating move in an arc centred on the first pin, a working stroke being transmitted to the tool by movement of the third pin from a position in alignment with the first and second pins in a direction away from the line connecting the first and second pins, to cause the first and second pins to approach one another. A first toggle arm B is pivotally mounted to the machine frame by a bracket 6 which is horizontally adjustable to predetermined positions. A second toggle arm A is pivotally attached at 8 to a frame RA which is guided for vertical movement in the machine frame and which carries a nibbling punch N. The common pivot of the arms A and B is connected by a rod V to a crank pin rotated by a shaft which is movable horizontally. In the rest position of the mechanism with the tool retracted from the work the crankpin is in the position 3 and the common pivot point is in the position 4 so that the toggle arms are in alignment. As the crankshaft rotates the common pivot point moves to the right, exerting a maximum force on the tool N at the beginning of the stroke. The force decreases and the speed of movement of the tool increases as the stroke progresses. By moving the crankshaft bodily to the left the common pivot point is positioned to the left of the aligned position, 41, Fig. 2, so that the period of time during which the tool is engaged with the work is reduced and the fraction of the cycle time available for feeding the work is increased.