| 摘要 |
A method of automatically wrapping in plastic film a shallow tray filled with irregularly-shaped contents such as meat or vegetables is provided. No elevator for tray movement is required yet the method forms a lap seal on the bottom of the tray with any of the modern soft plastic films, including stretching and shrink films. The trays advance into a curtain of the plastic film arranged transversely to a tray feed track. A first air blower blows onto the film surface above the tray, billowing the film smoothly ahead of the tray to prevent folds from forming in the film and to keep moving air between the tray and the film during tray advance to avoid snagging therebetween. A lower edge of the film is captured between the tray bottom and tray support rollers. The film is draped over the top and back of the tray. A second fan blows air upwardly onto the under-tucked film to ensure proper placement thereof. A tucking device displaces the support rollers downwardly and tucks and forms a lap joint between the film ends beneath the stationary tray. End folders then tension and fold the tubed ends of the film upwardly to the sides of the tray and downwardly to the bottom of the tray prior to shrinking or final heat treatment of the film.
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