Apparatus and process for stretch wrapping articles, especially heads of
lettuce, wherein a roll (23) of film (24) is supported on a housing
(21), and the film is supplied from the roll around a dancer roller (50)
and film feed roller (51) to a pair of film feed grippers (33, 34)
which grip a leading edge of the film and advance it past an opening (26),
whereupon a clamp (27) engages the leading edge of the film to hold it while
the grippers release and return to their home position. Additional clamps (28-32)
then engage the film to hold it in place over the opening. A head of lettuce (L)
is placed on the film in centered relation to the opening, and a ram (37)
engages the lettuce and pushes it against the film to stretch the film through
and below the opening. Gathering bars (38, 39) engage the film stretched
between the opening and the head of lettuce to gather the film in a first direction,
and a U-channel (40) and sealing and trimming mechanism (41) gather
the film in a second direction to produce a narrow necked down section of gathered
film, fuse and seal the necked down section to produce a wrapped head of lettuce,
trim excess film from the lettuce, and release the wrapped head of lettuce to drop
onto a take away conveyor. The film (24) is a polyethylene based multi-layer
film with an outer polypropylene layer for added gloss, slip and clarity, has a
300% stretch capability, is FDA approved for direct food contact, has an anti-fog
additive for moisture dissipation during temperature fluctuations, is thirteen
microns thick, and has a width of sixteen inches.