MECHANISM FOR LINING A SERIES OF SHELLS

摘要

Two series of endless chains each comprising a plurality of traylike open half-shells pivotally interconnected at their ends are arranged in close proximity to each other so that the working reaches of the chains are parallel and so that the open shells of one chain are disposed in opposed relation to the open shells of the other chain to form a series of cavities along the working reaches of the chains. A strip of heat sealable shrink film is disposed along and held against the open faces of the half shells of each of the chains by articulated force applying structure arranged to impart uniform force thereto and vacuum means is employed to draw the film into lining relation with each of the half shells. An assembly of items to be packaged is inserted into the space between two opposed half-shells adjacent the entry end of the working reaches of both chains. After the half-shells of one reach come into biased engagement with the open half-shells of the other reach to envelope as assembly of items to be packaged, a jet of heated air is applied along the top and bottom edges of the shells to form top and bottom seals between the strips thereby to form a series of interconnected packages. After the packages are formed by heat sealing, the mating shells are moved in opposite directions away from each other and heated air is subsequently applied to each package so as to shrink the film somewhat thereby to preserve the integrity of the package. Preferably the film is of the nonoriented type and is preheated before being drawn into the half shells.