The invention provides an endless conveyor having a pair of gaps in its product conveying surface. As a film-wrapped product is conveyed across the gaps, a sensor aligned with the second gap signals the initiation of a shrinking sequence by which a pair of upwardly directed nozzles impinge hot air on the portion of film below and inboard of the transverse film seals. As the flow of hot air begins, a pair of magnetic clutches are activated to transmit power from a drive to a pair of shafts on which each clutch is respectively mounted. The drive, through the clutches, causes each of the nozzles to rotate about an axis so that the stream of hot air follows the travel of the wrapped product to maximize the time of hot air exposure without slowing the speed of product travel. At the end of the arc through which the nozzle is pivoted, the hot air flow is shut off, the magnetic clutches are deactivated, and a biasing spring causes the nozzles to return to their respective starting positions. Subsequently, the package is conveyed through a shrink tunnel providing ambient hot air to shrink the balance of the film wrap.
The method relates to a method for packing articles and/or objects. Articles are packed in an elastic packing material (2) and the elastic packing material is stretched during the packing process. To achieve this, the packing material is arranged in a receptacle (1) in which a partial vacuum is produced. The packing material is stretched due to the pressure that the outside air exerts upon it. The item that is to be packed is then placed in or on the packing material. Once the vacuum has been removed, the packing material automatically reverts back to its original position by virtue of its own elasticity and is applied to the packing items. The invention also relates to a device to carry out such a method.
A packaging machine using a heat-shrinkable film comprises a frame (14, 16) for peripheral sealing of a film (19) segment and a tunnel (21) disposed alongside the frame, in which means (27) for air circulation is arranged, which air is heated by electrical heating elements (28) for shrinkage of the sealed film which is introduced into the tunnel. The machine comprises means (34) for detecting a condition associable with the presence in the machine of a product wrapped in a film to be shrunk. This detecting means (34) upon detection of said condition produces a signal (33) for temporary actuation of the hot-air circulation means (27).
An apparatus and method for controlling the size and shape of a shrink film envelope around an article or a package to prevent the formation of wrinkles and bunching of the film when it shrinks. The apparatus comprises a hot air shrink tunnel having a conveyor for moving the article on packages through the tunnel. An assembly is position within the tunnel a preadjusted distance away from the article forming a fixed boundary to which the film envelope expands and is restricted, causing the air within the film envelope to be directed to areas around the article to keep the film from touching the article until the film shrinks. The assembly comprises material of low thermal conductivity such as a plurality of wooden wheels for contacting the film envelope.
