| 摘要 |
Single commodities such as packets of cigarettes are enveloped in a thermoplastic wrapping and directed ultimately toward a heat seal station by way of a belt conveyor looped around at least one pulley; each packet is taken up from the belt, together with its wrapper, between two disks disposed coaxial with and on either side of the pulley, each consisting in two concentric circular rings rotating as one with the pulley and thermally insulated one from the other. The two inner rings are heated by resistances and positioned to engage and seal the end folds of the wrapper; as the seal is effected, the packet encounters a diverting element set between the disks and adjustable for position according to the operating speed of the wrapping machine, by which it is distanced from the center of the pulley and thus caused to pass from the inner rings to the unheated outer rings. |
