Wrapping machine

Abstract

A wrapping machine includes a mechanism for feeding a stretchable film, means for lift an article to be wrapped, a mechanism for underfolding the film, means for controlling the timing at which various elements of the wrapping machine are actuated, and means for adjusting the tension of the film. The film feeding mechanism clamps opposite edge portions of the film, which has been cut to a predetermined length, by a plurality of grippers to apply a prescribed tension to the film and extend the film at a predetermined position of the wrapping machine. The article lifting means is adapted to raise an article to be wrapped, which has been fed in by infeed conveyance means, into taut engagement with the film extended at the predetermined position. The film folding mechanism includes left and right folding plates disposed above the cut length of extended film at positions having left-right symmetry with respect to the article feed-in direction for underfolding left and right edge portions of the film covering the article from above, a front folding plate and a rear folding member disposed at positions perpendicular to the left and right folding plates for underfolding front and rear edge portions of the film, the left, right and front folding plates and the rear folding member defining a generally rectangular opening, and sliding means for moving the left, right and front folding plates toward the center of the opening. The film tension adjusting means adjusts the tension of the film wrapping the article by regulating the cut length of film in dependence upon the size of the article to be wrapped and by regulating the timing at which the grippers release their hold on the opposite edge portions of the film.