| 摘要 |
This machine comprises a frame, spacing means arranged in the interior (3) of the tubular film (1) to separate the walls, traction means (8) to draw the tubular film and an inflating and welding device (5, 6, 7, 12). The inflating and welding means is provided with at least one hollow needle (5) for inflation, means (2, 2a, and 2b) to prevent the air escaping toward said reel, that is to say, upstream. Said means (2) to prevent the escape of air are placed between the means (3) provided within the said film and the reel. The inflating and welding device (5, 6, 7, 12) is located after the means (3) provided within said film and before the traction means (8) for drawing said tubular film (1) through the inflating and welding device. The hollow needle (5) of the inflating and welding device is attached to a first beam (12) located on one side of the said film and controlled by a first actuator (13) and two heating elements (6) located upstream and downstream of the hollow needle attached to a second beam (10) located on the other side of said film controlled by a second actuator (11). The means for preventing the air introduced into the tubular film from escaping towards the said reel, that is to say, upstream, comprise an elongate element (2b) extending in a transverse direction relative to the film (1) attached to said first beam (12) in such a way as to be held away from said film during the movement of the latter and being introduced into a recess (2a) provided in a plate (2) on the frame of the machine to force said film into the recess to form a sealed fold in the latter.
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