GB1384450A - Wrapping machines - Google Patents

Abstract

1384450 Wrapping machines BAKER PERKINS HOLDINGS Ltd 18 July 1973 [24 July 1972] 34513/72 Heading B8C The invention relates to a wrapping machine in which packs 13 each constituted by a bundle of articles, are advanced in succession through a depending curtain 10, 10A of heat-sealable, and heat-shrinkable, wrapping material to cause the material to become wrapped around each pack as a loose open-ended sleeve 29 and which includes a sealing mechanism 24 operative to sever the sleeve 29 from the material of the curtain and to form, in the sleeve, a bead 12A extending transversely to the direction of advance of the pack and also another bead seal 12B between the portions of wrapping material severed from the sleeve and so reform the curtain. The machine is characterized in that it includes a pair of feed rollers 16, 17 disposed below the feed level of the packs and operative, after formation of a seal in the sleeve surrounding a pack 13A and reforming the curtain, to draw the wrapping material downwardly to an extent sufficient to present, to the next pack 13, a virgin curtain devoid of any bead seal and to relieve the recently formed bead seal 12B from tension as the next pack advances through the curtain. As shown, as a pack 13 moves up to a transfer position where it is transferred by a pusher 22 from a dead plate 14 to a discharge conveyer 15 the curtain 10, 10A of the two webs 10, 10A, sealed together at 12 is fed downwardly by feed rolls 16, 17 to form a reservoir 18 which contains the last-formed bead seal 12 and a further reservoir 20 which is formed from material drawn from a bottom supply reel 11A by a descending jockey arm 19, a film trap 21, comprising a weighted pad 21 and a co-operating roller 23, ensuring that there is no disturbance of the reservoir 18 which might put tension upon the recently-formed, bead seal 12. As the pack 13 moves through the curtain the rollers 16, 17 separate and the jockey arm 19 pivots upwardly web material first being drawn from the reservoir 18 until the latter is exhausted whereupon the film trap 21 yields to allow sufficient web material to be drawn from the reservoir 20 to complete the base of a sleeve wrap. As the pack is delivered on to the conveyer 15 the latter commences to move in synchronism with the pusher 22 until the latter reaches the end of its stroke whereupon the conveyer 15 stops and the pusher returns to its initial position. A sealing unit 24 then descends drawing off stored film from a top reel 11 until it strikes an anvil 25 to trap both webs 10, 10A between the anvil 25 and side clamps 26 of the sealing unit whereupon a knife 27 descends to effect two bead seals 12A, 12B and sever both webs. The sealing unit 24 then returns to its upper position as the discharge conveyer transfers the pack out of the machine and through a heat-shrinking unit. The bead seal 12 joins the two webs to reform the curtain. In a modification, Figs. 6, 8, the wrapping is formed solely by a web 10 of material drawn from an upper reel 11. As before the feed rollers 16, 17 feed the material 10 downwards as the pack 13 is advanced to form a reservoir 180 containing the last, and any previously formed bead seal, cooling air being blown on to the seal 12 from an orifice 30 as it moves into the reservoir 18. As the pack proceeds on to the conveyer 15 the material drawn from the reservoir to complete the base of the sleeve wrap is not sufficient to include any previously formed bead seals.