This invention relates to a mechanism for stripping- off formed cartons or like containers (hereinafter referred to simply as "cartons") i.e., removing formed cartons from a forming plunger for deposit on a conveyor which takes the cartons to filling, closing and/or sealing stations.

The object of the invention is to provide a strip-off mechanism that ensures positive transfer from the forming plunger down on to the conveyor instead of relying on gravity.

According to the present invention, a mechanism for stripping-off formed cartons from a forming plunger and transferring them positively down on to a conveyor comprises: a carrier mechanism adapted to be mounted alongside the conveyor adjacent the forming plunger; an arm extending from the carrier mechanism towards the conveyor; at least one suction cup (but preferably two or more) at the end of the arm nearest to the conveyor, with its suction face vertical; a source of suction; and valve means in a pipeline between the suction source and the suction cup; the carrier mechanism being adapted to move the arm in an upright plane in such a manner that the suction cup moves in a closed path having a downward run starting with contact with a carton on the forming plunger and ending with breaking contact with the carton as it contacts the conveyor, and an upward run withdrawn away from the conveyor and the forming plunger; and the valve means being adapted to apply suction at the suction cup during the downward run, to hold to a carton and pull it down from the forming plunger to the conveyor.

Between the downward run and the upward run, and vice versa, the movement of the suction cup may be linear, but preferably follows semicircles with which the downward and upward runs are tangential, and the timing of the valve means is preferably such that contact between the suction cup and each carton is broken at or approaching the bottom of the semicircle between the downward run and the upward run, whereby, with integral hinged-lid cartons, a carton being deposited on the conveyor is moved laterally to ensure that its upstanding lid is clear of the body of the next descending carton. Thus the carrier mechanism may comprise: an upright support assembly for mounting alongside and upwardly from the conveyor; four sprockets having a common pitch diameter on axes parallel to the conveyor at the upper and lower corners of a rectangle on the support assembly; two endless chains, one trained round the upper and lower sprockets nearest the conveyor and the other trained round the upper and lower sprockets remote from the conveyor; guide tracks for the chains between the sprockets; drive means for one sprocket in each pair of upper and lower sprockets, for driving the endless chains at the same speed and with the runs of both chains nearest the conveyor moving downwards; and a carrier block for the arm carrying the suction cup secured to each of two horizontally corresponding links one in each chain.

The arm preferably comprises a straight tube slidable along the carrier block, with the suction cup at the end of the tube nearest the conveyor (but preferably with that end of the tube communicating with a cross-tube carrying at least two

suction cups), while the other end of the tube is connected to a flexible pipe leading to the valve means, and locking means is provided on the carrier block for securing the tube in adjusted position with the suction cup (or cups) spaced from the downward runs of the chains to suit any of a range of carton sizes. The straight tube is preferably slidable in sleeve means upstanding from the carrier block, and the locking means is operable by screw means parallel to and below the straight tube; the sleeve means conveniently consists of two longitudinally spaced sleeve portions on upstands on the carrier block, and the locking means consists of a wedge block movable on an incline between the sleeve portions by a screw journalled in the upstands, the screw having a rotating tool- engageable head at the end nearest the suction cup.

A cross-tube as aforesaid may be provided with two pairs of suction cups when the strip-off mechanism is required for use with a double forming head producing two cartons at a time in line with the conveyor, the aforementioned path and breaking of contact of the suction cups being such that travel of the lid of the second carton of any pair on the conveyor takes place clear of the body of the first carton in the next formed pair being stripped from the pair of forming plungers in the double forming head.

The guide tracks may be formed, conveniently, in a plate of plastics material bolted to a metal framework having bearings for spindles for the sprockets, and one spindle in each pair of upper and lower spindles carries another sprocket for a common drive chain from a motor and/or gearbox, which

may also provide drives for a suction pump and a rotary valve for controlling the application of suction at the suction cup or cups.

A preferred embodiment of the invention and a highly advantageous development thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a small scale semi-diagrammatic side view of the mechanism mounted alongside a conveyor adjacent a forming plunger;

Figure 2 is a larger scale and more detailed side view of the carrier mechanism seen in Figure 1;

Figure 3 is a horizontal cross-section of the carrier mechanism, partly on the line A-A and partly on the line B-B of Figure 2, and extended to show - diagrammatically interrelated drives; and

Figure 4 is a small scale diagrammatic perspective view illustrating the highly advantageous development of the illustrated preferred embodiment.

Referring initially primarily to Figure 1, a mechanism for stripping-off formed cartons 10 from a forming plunger 11 and transferring them positively down on to a conveyor 12 comprises: a carrier mechanism 13 adapted to be mounted alongside the conveyor adjacent the forming plunger; an arm 14 extending from the carrier mechanism towards the conveyor; at least one suction cup 15 (but preferably, as seen in Figure 3, two or more, e.g., four as seen in Figure 4) at the end of the arm nearest the conveyor, with its suction face vertical; a

source of suction 16 (Figure 3); and valve means 17 in a pipeline 18 between the suction source and the suction cup; the carrier mechanism 13 being adapted to move the arm 14 in an upright plane in such a manner that the suction cup (or cups) 15 moves in a closed path 19 having a downward run 20 starting with contact with a carton 10 on the forming plunger 11 and ending with breaking contact with the carton as it contacts the conveyor 12, and an upward run 21 withdrawn away from the conveyor and the forming plunger; and the valve means 17 being adapted to apply suction at the suction cup (or cups) 15 during the downward run 20, to hold the carton 10 and pull it down from the forming plunger 11 to the conveyor 12.

Between the downward run 20 and the upward run 21, and vice versa, the movement of the suction cup (or cups) 15 follows semicircles 22, 23, respectively, with which the downward and upward runs are tangential, and the timing of the valve means 17 is such that contact between the suction cup (or cups) and each carton 10 is broken at or approaching the bottom of the semicircle 22 between the downward run 20 and the upward run 21, whereby, a carton being deposited on the conveyor 12 is moved laterally to ensure that its upstanding lid 10X is clear of the body 10Y of the next decending carton. This is highly advantageous in the development of the mechanism for use with a double forming head, as will be described presently with reference to Figure 4.

Thus, the carrier mechanism 13 comprises: an upright support assembly 24 mounted alongside and upwardly from the conveyor; four sprockets 25A, 25B, 26A, 26B having a common

pitch diameter on axes parallel to the conveyor 12 at the upper and lower corners of a rectangle on the support assembly; two endless chains 27, 28, one trained round the upper and lower sprockets 25A, 25B nearest the conveyor and the other trained round the upper and lower sprockets 26A, 26B remote from the conveyor; guide tracks 29, 30 for the chains between the sprockets in a plastics plate 31 (see particularly Figures 2 and 3); drive means 32 for one sprocket in each pair of upper and lower sprockets, for driving the endless chains 27, 28 at the same speed and with the runs of both chains nearest the conveyor 12 moving downwards; and a carrier block 33 for the arm 14 carrying the suction cup (or cups) 15 secured to each of two horizontally corresponding links 27X, 28X one in each chain.

The arm 14 comprises a straight tube slidable along the carrier block 33, with the end of the tube nearest the conveyor communicating with a cross-tube 34 carrying two suction cups 15, while the other end of the tube is connected to the pipeline 18 which is flexible, and locking means 35 is provided on the carrier block for securing the tube 14 in adjusted position with the suction cups spaced from the downward runs of the chains 27, 28 to suit any of a range of carton sizes. The tube 14 is slidable in sleeve means consisting of two longitudinally spaced sleeve portions 36, 37 on upstands on the carrier block 33, and the locking means 35 consists of a wedge block 38 movable on an incline 39 between the speeve portions by a screw 40 journalled in the upstands parallel to and below the tube 14, the screw having a rotating

tool-engageable head 41 at the end nearest the suction cups.

The plastics plate 31, in which the guide tracks 29, 30 are formed, is bolted to a metal framework 42, having bearings 43 (Figure 3 only) for spindles 44A, 44B, 45A, 45B for the sprockets 25A, 25B, 26A, 26B, and one spindle 44B, 45A in each pair of upper and lower spindles carries another sprocket 46, 47 for a common drive chain 48 from a sprocket 49 on a shaft 50 driven by a motor/gearbox combination 51 (indicated diagrammatically in Figure 3) and tensioned by- an idler sprocket 52 on an adjustable bracket 53. The motor/gearbox combination 51 is also indicated in Figure 3 providing drives for a suction pump and a rotary valve constituting the suction source 16 and the valve means 17 for controlling the application of suction at the suction cups 15. The shaft 50 may also provide the drive for crank and linkage arrangements (not shown) for reciprocating the plunger 11 and also for feeding carton blanks from a magazine to a die through which the plunger 11 is pushed to form the cartons 10.

Figure 1 also includes an upstanding guide plate 54 mounted along the conveyor 12 to guide the erected and open cartons 10 to a product loading machine (not shown), and in Figure 4 a similar guide plate 54X is shown having an inverted T-shaped slot with an upright part 55 for the tubular arm 14 to pass down and a horizontal part 56 for an elongated cross- tube 34X to pass through. It will be appreciated that the guide plate 54 in Figure 1 will have a similar T-shaped slot in which the horizontal part will be appropriately shorter in conformity with the shorter cross-tube 34.

The elongated cross-tube 34X in Figure 4 is indicated as carrying two pairs of suction cups 15U, 15D when the strip- off mechanism is required for use with a double forming head (not shown) producing two cartons 10U, 10D at a time in line with the conveyor 12, the aforementioned path 19 with a semicircle 22 between the downward run 20 and the upward run 21 and breaking of contact of the suction cups 15U, 15D with the cartons at or approaching the bottom of the semicircle 22 ensuring that travel of the lid 10X of the second or upstream carton 10U on the conveyor takes place clear of the body 10Y of the first or downstream carton 10D of the next pair of cartons being pulled down from the pair of forming plungers (not shown) in the double forming head.

It will be appreciated that the speed of the conveyor 12 must be such that the lid 10X referred to must have passed downstream of the upright part 55 of the inverted T-shaped slot before the tubular arm 14 passes down that slot part, and that the body of that same carton 10U must have passed downstream of the horizontal part 56 of the said slot well before the cross-tube 34X moves to deposit the next pair of cartons on the conveyor and also pass through that latter slot part.