| 摘要 |
1,069,287. Making thermoplastic bags. H. MEMBRINO. Aug. 13, 1964 [Aug. 16, 1963], No. 33031/64. Heading B5D. [Also in Division B8] A machine for making bags from a roll of thermoplastic strip has a sensing element' controlling movement of the strip, one or more rotatably driven heat-sealing and cutting elements having one or more thermally insulated interruptions to form spaced interrupted lines of seal and severence in the strip, and means for packaging the bags after conveying them from the element. Thermoplastic strip (130) in the form of a flat tube or sheet folded longitudinally is fed, via rollers (144, 134) and a speed control (not shown) operated by a photo-electric device (146), between an impression roller (58) and a sealing head (56) which comprises a series of discs (162) mounted on a shaft (38) which have two heater bars (164) heated by resistance wires (166) extending transversely across the peripheries of the discs. A set of tapes 148 pass round the impression roller (58) to prevent the strip wrapping itself around the roller (58) and these tapes cooperate with similar tapes (152) extending around the discs (162) and externally of the heater bars (164) and wires (166) so that the heat seals and severs made in the thermoplastic strip as it passes by the rotating sealing head (56) are formed with interruptions corresponding to the tapes (152). A static eliminator is indicated at (196). The connected bags formed from the partly severed strip are passed on to an endless conveyer (198), past a knife (232) which slits open the strip if this is in the form of a tube to a conventional filling device (230) incorporating a tube (238) emitting compressed air to open the bags to facilitate filling. A sponge rubber roller (250) expels trapped air and a heat-sealer (254) closes the bag mouths. A roller (268) guides the bags between oscillating rollers (276) to stack the bags concertinawise; additionally, a series of sprocket holes may be provided in the bags for the strip to be fed for stacking in a manner similar to a film in a camera. The conveyer (198) and its associated parts may be pivoted about (212) to a vertical position to aid filling. In modifications, the bags may be wound in a roll instead of stacked or be separated from each other by differentially speeded rollers before filling, the holes left in the interrupted seams either being retained for ventillation or being sealed by a reciprocating heat seal means. |
