| 摘要 |
Means are provided to ensure that during the stage of formation through the tube- forming and longitudinal welding means ( 1, 18 ) the wrapping is subjected to longitudinal stretching which causes it to adhere intimately in a direction transverse to the product and this condition is ensured by means which bring about a particular difference in velocity between the jaw ( 19, 119 ) which supports the tubular wrapping and causes it to advance and the means ( 15, 115, 17 ) which feed the film to the tube-forming means ( 1 ) which also remain suitably active during the subsequent stage in which the tubular wrapping is seized posteriorly by the appropriate posterior closing jaw ( 119, 19 ), all in such a way that the wrapping film runs over the said tube-forming means in an almost continuous movement to prevent localised appearance defects in the packaging and to assist operation of the longitudinal welding means ( 18 ) which are then able to operate substantially continuously. |
