This invention relates to a mechanism for turning cartons, or other containers, in, for example, packaging machinery between successive operations for ploughing down and sealing flaps of lids.

An object of the invention is to provide a carton turning mechanism for use with a flightless or a flighted conveyor carrying cartons possibly at random intervals, and with use of which turning of cartons is effected with minimised deviation of the cartons from a straight path.

Another object is to provide such a mechanism suitable for a wide range of carton sizes with minimum adjustment of the machinery.

A further object is to provide such a mechanism capable of operating at relatively high speed but with minimised noise and/or vibration.

According to the present invention, a carton turning mechanism for use with a conveyor carrying cartons comprises an endless driven member in a plane parallel to the plane of the forwarding run of the carton conveyor, a forward run of the driven member alongside the forwarding run of the carton conveyor, means for driving the driven member so that its forward run moves in the same direction as but at a slightly lesser speed than the forwarding run of the carton conveyor, a succession of lugs carried by the driven member and adapted to project along the forward run of the driven member into the path of cartons on the conveyor, whereby a lug in the forward run of the driven member will be abutted by the

nearside leading corner of a carton and will cause turning of the carton about the lug because of the difference in speed between the carton conveyor and the driven member, the endless driven member being guided along its forward run so as to be bowed towards its return run to allow some lateral movement of the corner of a carton abutting a lug as the carton rotates about its centre of gravity moving in substantially a straight line along the carton conveyor, and the extent of bowing being such that the centre of gravity of each carton does not move in the opposite lateral direction past the line followed by the centre of gravity from completion of the turn.

The carton conveyor preferably has an upstream portion and a downstream portion, with means for driving the downstream portion independently of the upstream portion and adjustable to ensure that each carton will be turned o substantially through 90 before the respective lug becomes disengaged from it adjacent the downstream end of the forward run of the driven member. The upstream portion of the carton conveyor may be driven by the means for driving the endless driven member through appropriate gearing to provide for the slightly lesser speed of the endless driven member.

Conveniently, to make the carton turning mechanism suitable for a wide range of carton sizes with minimum adjustment of the machinery, the driven member is provided with a continuous closely-spaced succession of lugs on vertical axes, together with guide track means alongside the forwarding run of the carton conveyor to constrain each lug in an advanced position in which it will project into the path of

the nearside leading corner of a carton or in a retracted position in which it will not so project, cam track means adjacent the trailing end of the forward run of the driven member to bring every lug in advanced position into retracted position, detector means upstream along the carton conveyor for detecting the presence of a carton, switching means between the camtrack means and the leading end of the guide track means for moving a selected lug from, retracted position to advanced position, and control means activated by the detector means to trigger the switching means to move the appropriate lug from retracted to advanced position before it moves into the forward run ready for abutment by the nearside leading corner of the carton detected by the detector means.

Further cam track means is preferably provided where the return run of the driven member leads into a bight leading to the forward run of the driven member, and the switching means is located in that bight adjacent a gap between the cam track means and the guide track means.

The switching means may be mechanical, but is preferably electromagnetic means or suction/blown air means for high speed operation with minimised noise and/or vibration.

The endless driven member is conveniently a chain, guided between forward and return runs by a guide block at the upstream end and by a sprocket, at the downstream end, which sprocket is driven by a motor through a gearbox affording the slight reduction in speed of the chain compared to the carton conveyor or the upstream portion of the carton conveyor (which

may be driven by the same motor or its own motor through another gearbox), the chain being guided along the forward and return runs in respective bowed and straight channels in a plate (preferably made of plastics material with localised drain holes in the bottoms of the channels), some of the link pins of the chain being extended upwardly to form pivot axes' for the lugs, the undersides of which are provided with grooves or with downward projections for engaging an underlying guide track for constraining lugs in advanced position or for constraining lugs in retracted position.

Figure 1 of the accompanying drawings is a diagram illustrating the principle involved in any carton turning mechanism in accordance with the present invention.

An endless driven member A lies in a plane parallel to the plane of the forwarding run B of a carton conveyor, and a forwarding run C of the driven member moves in the same direction as but at a slightly lesser speed than the forwarding run B of the carton conveyor. A succession of lugs D are carried by the driven member A and project (at least along the forwarding run C) into the path of cartons E on the conveyor, whereby a lug at Dl in the forward run C of the driven member will be abutted by the nearside leading corner - of a carton El and will cause turning of the carton, as indicated by the arrow F, about the lug because of the difference in speed between the carton conveyor and the driven member. The forward run C of the drive member is guided so as to be bowed towards its return run to allow some lateral movement of the corner of carton E abutting a lug D as the

carton rotates about its centre of gravity G moving in substantially a straight line H as the carton is moved along by the conveyor to position E2, and the extent of bowing of the forward run C of the driven member is such that the centre of gravity of each carton does not move in the opposite lateral direction past the line J followed by the centre of gravity from completion of the turn at position E3.

A preferred embodiment of the invention will now be described in detail with reference to the remaining drawings in which

Figure 2 is a small scale plan of the carton turning mechanism;

Figure 3 is a full scale plan of one of the lugs incorporated in the mechanism of Figure 2;

Figure 4 is an elevation in the direction of the arrow

IV in Figure 3;

Figure 5 is an elevation in the direction of the arrow

V in Figure 3;

Figure 6 is a section from the line VI - VI in Figure

3;

Figure 7 is an underneath plan of the lug;

Figure 8 is a fragmentary vertical section on the line VIII - VIII in Figure 2;

Figure 9 is a fragmentary plan taken from the line IX - IX in Figure 8;

Figure 10 is a part vertical section from the line X - X in Figure 2, but with a middle portion omitted;

Figure 11 is a downward continuation of the right hand

part of Figure 10 mating on the line XI - XI;

Figure 12 is an enlargement of part of Figure 2 partly in section on the line XII - XII in Figure 13;

Figure 13 is a fragmentary vertical section on the line XIII - XIII in Figure 12;

Figures 14 and 15 are fragmentary diagrammatic plans illustrating the operation of the lug switching means seen in Figures 12 and 13;

Figure 16 is a plan of a guide plate incorporated in the mechanism; and

Figure 17 corresponds to Figure 2 but shows a different 'size of carton being turned by the same mechanism.

To make the preferred embodiment of carton turning mechanism suitable for a wide range of carton sizes (c.f. Figures 2 and 17) with minimum adjustment of the machinery, the driven member 20 is provided with a continuous closely- spaced succession of lugs 21 on vertical axes 22 which are upward extensions of some of the link pins of an endless chain forming the driven member, which chain is guided along the foward and return runs 23, 24 in respective bowed and straight channels 25, 26 in a plate 27 (see particularly Figure 16) made of plastics material with localised drain holes 28 in the - bottoms of the channels. The return path of the chain 20 departs from a straight path where the plate 27 is cut away at 29 to accommodate a chain tensioner 30 (see Figures 2 and 17).

A guide track 31 on the plate 27 underlies the lugs 21 alongside the forwarding run of the conveyor 32 which carries

the cartons 33 to be turned in readiness for ploughing down and sealing end flaps 33X of their lids, which guide track co¬ operates with features on the undersides of the lugs to constrain each lug in an advanced position in which it will project into the path of the nearside leading corner of a carton or to constrain it in a retracted position in which it will not so project. As can be seen in Figure 3 to 7 the underside of- each lug 21 has two converging grooves 34, 35 forming between them a projection 36 for restraining to one side or the other of the guide trade 31 as determined by switching means 37 (see Figures 12 to 15 in particular, but also Figures 2 and 17) between the return run 24 and the forward run 23.

Cam track means 38 (see Figures 2, 8, 16 and 17) adjacent the trailing end of the forward run 23 of the driven member 20 bring every lug in advance position into retracted position, and this cam track means continues concentrically with a sprocket 39 for the endless chain 20 between the downstream end of the forward run 23 and the return run 24. The cam track means 38 starts at the inside of a tongue the outside 40 of which assists in the final turning of the cartons 33. Further cam track means 41 adjacent the other end of the return run 24 lead into the switching means 37.

Detector means 42 (see Figures 2 and 17 only) upstream along the carton conveyor 32 is mounted on a slide 43 for setting adjustment, and control means 44 is provided for activation by the detector means to trigger the switching means 37 to move the appropriate lug 21 from retracted

position to advanced positions before it moves into the forward run 23 ready for abutment by the nearside leading corner of the carton 33 detected by the detector means. A shaft 45 for driving the sprocket 39 carries a gating device 46 for synchronising the timing of the switching means with the position of the appropriate lug following detection of the relevant carton.

The switching means 37 comprises an arcuate body 47 (see Figures 12 to 15) inside the bight of the driven member 20 from its return run 24 to its forward run 23, with a suction hole 48 flanked at a lower level by a pair of compressed air ports 49 controlled by valves 50 actuated by the control means 44 to blow a selected lug from retracted position to advanced position as it passes a gap 51 between the cam track means 41 and the guide track 31. The face 52 of each lug 21 that slides round the arcuate surface of the body 47 has a rebate 53 at the level of the compressed air ports 49 so as to avoid the coanda effects which would delay or prevent movement of a selected lug from retracted position tc advance position. The cam track means 41 ends with a spring- loaded tongue 54 to ensure that, when compressed air is not applied to the ports 49, the face 52 of each lug is in close contact with the body 47 until suction applied to the hole 48 holds the lug in retracted position as it passes the gap 51.

When a selected lug 21 is blown by compressed air in the ports 49, the lug continues movement under centrifugal force, until the projection 36 on the underside of the lug passes outside a stainless steel nose 55 on the guide track 31

(see Figure 14). When compressed air is not applied to the ports 49, suction in the hole 48 holds each lug until the projection 36 passes inside the nose 55 on the guide track 31 (see Figure 15) .

The conveyor 32 carrying the cartons 33 is ^' a roller conveyor the rollers 56, 57 of which are in two groups or conveyor portions 32A, 32B. The upstream group of portion 32A (which consists of seven rollers 56) is driven at a fixed speed by a friction drive 58 (see Figure 10) from a cross- shaft 59 driven by a motor 60 (see Figure 11) through a gearbox 61 and gear-belt drives 62, 63. The motor 60 also drives the shaft 45 carrying the sprocket 39 through gearing (not shown) providing for the slightly lesser speed of the endless driven member as compared with the roller conveyor portion 32A. The downstream group or portion 32B of the conveyor 32 (which portion 32B consists of twenty-three rollers 57) is driven independently of the upstream portion 32A and adjustably by a friction drive 64 from a gearbox 65 driven by a motor 66, the speed of the downstream portion 32B being adjusted to ensure that each carton 33 will be turned o substantially through 90 before the respective lug 21 becomes disengaged from it by the cam track means 38.

The motor 60 may also drive a vacuum pump 67 indicated in Figure 11 for applying suction to the hole 48 in the body

47 of the switching means 37, or the vacuum pump may have its own independent motor. A compressor may be likewise included to provide compressed air to the ports 49 through the valves

50, or the latter may be coupled to a compressed air line

already available at the packaging plant.

In Figure 17 like reference numerals denote like parts to those in Figure 2. Both of these Figures include indications of top inlet and outlet friction drives 68, 69, respectively, co-acting with inlet and outlet conveyors which have not been detailed.

A cover plate 70, having the same area as the plastics plate 27 on which it is secured, is shown in Figures 8 and 13 but - of course - it is omitted from Figures 2, 16 and 17 to enable the enclosed components and assemblies to be seen.

Whilst the suction/blown air switching means is preferred, particularly for high speed operation with minimised noise and vibration, it will be appreciated that mechanical or electromagnetic switching means could be readily installed instead.