Patent GB-1412730-A (GB)
Title: Wrapping machine
IPC: B65B11/54
Filed: 1972-05-03
Abstract: 1412730 Wrapping articles MAPAC PACKAGING Ltd 8 Nov 1972 [16 Nov 1971] 53209/71 Heading B8C A method of wrapping an article comprises locating a sheet of wrapping foil adjacent the article, moving the article relative to the sheet so as to contact the wrapping foil with the article and drape the foil around the article, first smoothing the foil to close the remaining open side portion of the article inwardly from four positions equispaced about the article towards the centre of said side portion and thereafter bunching the remaining pleats of foil into four bunched ribs each extending from the edge of the article toward the centre of said side portion. In an apparatus for carrying out the method when an article, such as a tray carrying, e.g. meats, fruit, or vegetables, is centrally located on a conveyer 27 the latter is stopped and a carriage 14, with clamping jaws 15, or a suction bar, or the like, is advanced between spaced ring formers 28 to grasp the end of the packing film supplied by a roller 11, and is then retracted to draw the film across the formers 28. The article is then raised, by an hydraulic lift 26 into the film and through the formers 28, the film, draped around the article, being cut with a hot wire 13 and released by the jaws 15 while the article is held by a pair of clamps 60 just above the level of two spaced-apart sets of four primary, and secondary, folding blades 29, 30 respectively. Fig. 2 shows only three blades 29, two blades 30, and one clamp 60. A camoperated linkage 32 is operated to move the primary blades 29 radially inwardly together to fold the draped film under the package so that it hangs, as four pleats, through the cruciform gap between the blades 29. A cam-operated linkage 33 is next operated to slide the secondary blades 30 endwise, and radially inwardly, along the respective edges of the blades 29 to cause the pleats to be bunched up to form four neat ribs which extend from an edge beneath the article to a common central point, excess film being bunched into a tight circular bundle in the middle of the underside of the package. Subsequent operation of the linkages 32, 33 spreads the sets of blades 29, 30 to release the package, the lift 26 being lowered to place the package back on to the conveyer 27 by which it is removed from the wrapping station, and, if desired, into a heating tunnel. The clamping rings 28 may be replaced by two pairs of clamping bars, and the lift table may be provided with a tamping head, or hot plate to tamp the central bunch of the wrapping and assist the final sealing of the film. The central bunch may be twisted. Alternative shapes for the blades 30 are described, Fig. 4, not shown, and the primary blades 29 may be shaped to correspond with that of the article being packaged. The ends of the secondary blades 30 are preferably re-entrant, and this set of blades may have opposite pairs of coplanar blades in two adjacent planes, one pair of blades being adapted to close before the other. The blades 30 may be mounted slidably on the blades 29. A tray may be provided with re-entrant grooves to receive the bunched ribs of packaging.