| 摘要 |
<p>Apparatus for pre-stretching wrapping film (33) includes an assembly of rotating arms (35) mounted on a fixed shaft (22). The arms (35) are driven by a wheel (39) which is rotated about an axis (49) off-set from the axis of the fixed shaft (22). Rollers (46) connect the wheel (39) to an adjustable guide ring (34) and rollers (47) run in a channel (48) in the lower face of the lower brace (29) of the arm (35). As the wheel (39) is rotated about its axis, the arms (25) rotate about fixed shaft (22) so that the included angle between adjacent arms (25) increases and decreases cyclically so that the linear speed of the film (33) will be increased so as to stretch the film as it passes around the assembly of rotating arms.</p> |
