| 摘要 |
A press comprising a frame with an anvil support and a punch carrier, the latter being mounted on the frame so as to be movable between two ends of travel towards and away from the anvil support. A piston and cylinder arrangement is arranged to act on the punch carrier to urge the latter in a direction towards the anvil support. That one of the two ends of travel of the punch carrier which iscloser to the anvil support is defined by a part or parts of the press itself. A limit switch is operable by means of the motion of the punch carrier, or a part connected thereto, in the said direction when the remaining available travel is a distance which is less than the thickness of an operator's finger, to enable the piston and cylinder arrangement to act on the punch carrier with a working force in the said direction up to the end of its travel. There is a detector switch preferably connected to or arranged in the punch carrier, to detect when there is a resistance to movement of the punch carrier towards the anvil support. The detector switch is connected to control operation of the piston and cylinder arrangement to stop further such movement of the punch carrier following detection of such a resistance in the event that the limit switch has not been operated. |
