| 摘要 |
1,035,031. Plastics sheet, cutting and welding. M. LEHMACHER, and J. M. LEHMACHER. Feb. 1, 1963 [Feb. 12, 1962], No. 4276/63. Headings B5A and B5K. Apparatus for severing and/or welding a foil or foils 15 of thermoplastic material comprises clamping jaws 21, 21a and 22, 22a, a heated bar 23 which may sever and/ or weld the foil and a stretching device 26, 27 which may be placed in or out of contact with the foil. The foil may be folded to form two thicknesses (Fig. 1, not shown) and be intermittently fed through the apparatus by rollers 18, 19. When the foil stops it is clamped by the jaws and the heated bar 23 having a double bevelled edge is lowered to cut the foils at 11 and from welds, at 10, 12; thus bags are produced. In Fig. 2, not shown, a tubular film is passed through the apparatus and only jaws 21, 21a are operated; the heated bar 23 is reversed to provide a single bevel. The stretching device 26, 27 is engaged with the foils so that when the bar 23 is lowered one portion of the severed foils is pulled clear while the other is welded; again bags are produced. If neither pair of jaws clamps the foil then a simple cut is effected. The blade 23 may be replaced by a serrated member so as to produce a row of perforations. Any or all of the jaws may be heated so that they perform a welding as well as a clamping action. In Fig. 8 (not shown) the jaws 21, 22 are formed integrally and the bar 23 is positioned in a channel cut therein. The jaws are rotatable through 180 degrees so that when the unit is moved against the foil the adjacent clamping surfaces can lie either in the same or different planes. A web of P.T.F.E. is directed over the foil engaging surfaces and may be wound across the surfaces when it becomes worn. |
