| 摘要 |
A cutting device for severing sheet material comprises a pneumatic cylinder defining a cylinder chamber having opposite first and second ends; a piston longitudinally slidably received in the cylinder chamber for executing working strokes between the first and second ends; a cutting blade situated at least partially externally of the cylinder and being secured to the piston for travel with the piston as a unit; a pressurized air vessel; and a first and a second switching valve connected to the respective ends of the cylinder chamber and to the presurized air vessel. Each switching valve has a first position in which pneumatic communication is maintained between the pressurized air vessel and a respective cylinder chamber part and a second position in which the respective cylinder chamber part is vented. The device further has an assembly for recharging the pressurized air vessel with pressurized air to a predetermined pressure solely prior to each working stroke of the piston and for allowing the pressure to diminish in the pressurized air vessel during each working stroke of the piston. There is further provided an arrangement for coordinating operations of the first and second switching valves and the recharging assembly.
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