| 摘要 |
<p>1,240,341. Cutting presses; moulding plastic substances. STAFFORD TOOL & MACHINE CO. Ltd. 14 March, 1969 [29 March, 1968], No. 15221/68. Headings B4B and B5A. A press machine comprises upper and lower platens 10, 12, relatively movable by means of two piston and cylinder units 18, 19, the units having cylinders of different capacity and being adjustable in their operative positions. A form tool 11 is provided on the platen 10, being heated, e.g. by a high-frequency generator, at least during part of the down-stroke. The platen 10 is supported by a stem 13 acted on by a lever 15 pivotable about an axis 16 on a main frame 91 by means of rams 20, 23 of the units 18, 19. A support block 26 is vertically adjustable to alter the operative positions of the units 18, 19 by sliding a movable wedge element 27 by means of a rotatable member 29 on a rod 81 acting through a mechanical linkage 28, further piston and cylinder means preferably supporting the block 26 during such adjustment. Also, an eccentric bearing 30 allows adjustment of the unit 18 relative to the unit 19. Operating cycle.-During initial setting up, a relatively soft lower platen backing, e.g. of brass, is lightly scored by the tool 11 to form a die. A workpiece, e.g. comprising several layers of sheet material, preferably thermo-plastic, is positioned, and a timing device is activated, switching on the heat supply e.g. just before the tool contacts the workpiece. Under the action of the ram 20, the tool penetrates the workpiece to a controlled extent, whereupon the heat supply is cut off, and, generally after a controlled interval to allow setting of the plasticized workpiece material, the larger unit 19 delivers a sharp force to complete the cutting cycle.</p> |
