GB2429688A

GB2429688A - Labelling machine

Info

Publication number: GB2429688A
Application number: GB0517758A
Authority: GB
Inventors: Keefe Paul Mccarthy; Peter John Woolls
Original assignee: SOVEREIGN LABELLING SYS Ltd
Current assignee: SOVEREIGN LABELLING SYS Ltd
Priority date: 2005-09-01
Filing date: 2005-09-01
Publication date: 2007-03-07
Anticipated expiration: 2025-09-01
Also published as: GB2429688B; GB0517758D0

Abstract

A labelling machine comprises a rotatable turret 40 having a plurality of pairs of posts 44 symmetrically disposed about the rotational axis of the turret and extending parallel to said rotational axis. A conveyor 30 transports articles 16 to be labelled transversely to the rotational axis of the turret, each conveyed article passing twice between two adjacent pairs of posts of the turret, once at an entrance end and once at an exit end of the turret. A continuous self-adhesive tape is adhered to the posts 44 of the turret lying to one side of the conveyor 30. The turret is indexed in synchronism with the movement of the conveyor so as to position a length of the tape 51 in the path of a conveyed article at the exit end of the turret. The tape 51 is severed between the posts of one of the pairs of posts straddling the conveyor at the exit end of the turret by means of a knife 70. The severed length of the tape is then transferred to the leading surface of the article 16 to serve as a label. The ends of the label may be pressed onto sides of the article 16 by pivoted gates 80. The articles 16 may be additionally supported from above by conveyors 32a, 32b, 32c.

Description

LABELLING MACHINE

The present invention relates to a labelling machine and is particularly applicable to labelling articles such as plastics milk bottles.

Conventionally, the labels applied to milk bottles are pre-printed and carried as individual labels on a continuous web having a release coating. Aside from the fact that such labels are more expensive to manufacture, additional expense is incurred in disposing of the carrier web. It would therefore be desirable to form labels as a continuous self- adhesive tape and the present invention seeks to provide a labelling machine that can apply individual labels to articles from such a continuous tape.

In accordance with the present invention, there is provided a labelling machine comprising a rotatable turret having a plurality of pairs of posts symmetrically disposed about the rotational axis of the turret and extending parallel to said rotational axis, a conveyor for conveying articles to be labelled transversely to the rotational axis of the turret, each conveyed article passing twice between two adjacent pairs of posts of the turret once at an entrance end and once at an exit end of the turret, means for adhering a continuous self-adhesive tape to the posts of the turret lying to one side of the conveyor, means for indexing the turret in synchronism with the movement of the conveyor so as to position a length of the tape in the path of a conveyed article at the exit end of the turret, and means for severing the tape between the posts of one of the pairs of posts straddling the conveyor at the exit end of the turret, the severed length of the tape being transferred to the leading surface of the article to serve as a label as the article is transported by the conveyor between the two pairs of posts at the exit end of the turret.

If the articles are tall, as is the case with milk bottles, and they meet resistance only at their lower end as a label is applied to them, there is a risk of the articles toppling. It is therefore preferred for the articles to be supported from below on a horizontal conveyor and for their upper ends to be steadied by contacting a second conveyor running parallel to and above the main conveyor.

The upper conveyor cannot of course be formed as a single section but it can be formed as three separate sections with the central section disposed between the entrance and exit ends of the turret being driven separately from the conveyor sections outside the turret.

When labels are formed as a continuous tape, it is important to be able to separate the labels at the correct position between their borders. Even if the length of tape cut should differ only slightly from the length of each printed label, then as time progresses the cutting will move further and further out of phase with the borders and each applied label will consist of the rear end of one printed label and the adjoining front end of the next.

In order to ensure correct phasing of the cutting of the labels from the continuous tape, it is preferred for the length of each label to be greater than the separation between adjacent pairs of posts on the turret and to provide means for varying the slack in the tape as it is adhered to the posts.

The means for varying the slack in the tape may comprise a reciprocating or oscillating arm carrying a tensioning roller that is movable radially with respect to the axis of rotation of the turret between two adjacent pairs of posts on the turret.

Preferably, the movement or length of the arm may be varied in dependence upon a feedback signal from an optical sensor monitoring the position of regularly spaced indexing marks on the tape. If the labels being severed are of a different length from the printed labels, then the position of the indexing marks will tend to drift with reference to the position of the optical sensor and the direction of the drift is indicative of whether the labels are too long or too short. When the optical sensor senses a drift indicating that the labels are too short or too long, the amount of slack introduced by the tensioning arm in the length of tape extending between adjacent pairs of posts can be increased or decreased, respectively, to effect the necessary compensation.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a labelling machine of the invention viewed from one side, Figure 2 is a perspective view of part of the labelling machine of Figure 1, Figure 3 is a perspective view from above of the labelling machine of Figures 1 and 2 with the top part of the machine cut away, and Figure 4 is a plan view from above of the labelling machine with the top part of the machine cutaway.

The labelling machine 10 shown in the drawings is a freestanding unit supported on a base 12 with feet 14 that are adjustable to allow its level to be matched to that of an existing conveyor in a bottling plant. Though the invention is being described herein by reference to a bottling plant, it should be clear that the labels can be applied to articles other than bottles.

In order to ensure that bottles 16 entering the labelling machine 10 are maintained a constant distance apart, a spacer unit generally designated 18 is provided on the input side of the labelling machine 10. The spacer unit 18 comprises a conveyor 20 which moves in synchronism with two counter rotating screws 22. The screws are formed with helical grooves 24 having a pitch matching the desired separation of the bottles 16 when they enter the labelling machine 10. This design of spacer unit 18 is not of fundamental importance to the invention and alternative designs may be adopted so long as a constant spacing is maintained between the bottles 16 as they enter the labelling machine 10.

Within the labelling machine 10, the bottles 16 are transported on a conveyor 30 on which the bottles 16 rest.

In addition, in order to prevent the bottles 16 from toppling and to steady them as they are being transported through the labelling machine 10, a second conveyor 32 contacts the tops of the bottles 16. For reasons that will become apparent below, the upper conveyor 32 is formed of three separate sections, designated 32a, 32b and 32c. To help in understanding the method of operation of the labelling machine 10, the upper conveyor 32 has been cut away from Figures 3 and 4, its function being only to help transport the bottles through the labelling machine.

The mechanism used to apply labels to the bottles 16 as they are being transported by the conveyors 30 and 32 comprises a turret 40 that is rotatable about a vertical axis. The turret 40 comprises a top plate 42 and six pairs of posts 44 which extend downwards from the plate 42. It is because the posts 42 have to cross the path of the upper conveyor 32 that the latter has to be formed in three separate sections, the section 32b being contained entirely within the volume swept by the posts 44 as the turret 40 is rotated.

The section 32b of the conveyor is mounted on a stationary tube 47 about which the turret 40 rotates. The section 32b, like the other two sections 32a and 32c, includes its own electric motor driving a continuous belt.

Electric cables carrying power to the motor and control signals to enable all three sections of the conveyor 32 to be synchronised with one another, are passed down the stationary tube 47. It would be alternatively possible to pass mechanical drive through the tube 47 from a motor mounted above the labelling machine, in which case a single motor could be used to drive all three sections of the conveyor 32. This would avoid the need to take steps to synchronise three separately driven sections.

A supply roll 50 of labels is mounted for rotation about a spindle 52. The supply roll 50 comprises a self adhesive tape 51 which has glue on only one side. The opposite side of the tape is preferably covered with a release coating but this is not essential. The tape carries printing either on its rear side that is coated with glue or on its exposed front side. The construction of the tape is not of importance to the present invention, which is more concerned with the manner in which lengths are cut from the tape to form individual labels and the manner in which the individual labels are applied to the bottles 16.

A run of tape 51 drawn from the supply roll 50 is guided over a set of guide pins 54. As these pins 54 only contact the front side of the tape and do not come in contact with the glued side, it is permissible to allow the tape to slide over them, especially if the tape has a low- friction release coating. Of course, if the friction between the tape and stationary posts should prove excessive, then the pins 54 can be surrounded by rotatable sleeves to act as rollers. With its adhesive side now facing the axis of rotation of the turret 40, the tape 51 is adhered to the posts 44 as the turret rotates.

As is best seen in Figures 3 and 4, there are six pairs of posts 44 on the turret 40. With the conveyor 30 travelling from left to right in Figure 4, the six pairs of posts come to rest at the even numbered positions on a clock face and to assist in distinguishing the different pairs of posts from one another they have been assigned in Figure 4 roman reference numerals corresponding to their position on a clock face. The two pairs of posts VIII and X define the entrance end of the turret 40 and the two pairs of posts II and IV define the exit end. The tape 51 is pushed by an oscillating tensioning arm 60 on to one of the posts in the pair designated VIII and as the turret is rotated counter clockwise as viewed in Figure 4, the tape 51 is carried around by the posts until it extends, as shown, from the posts VIII to the posts II. The section of tape extending between the posts II and IV thus lies across the exit path of bottles 16 on the conveyor. A sharp knife 70 operated by a suitable electromagnetic or pneumatic actuator is provided to sever the tape across its entire width at a position between the pair of posts IV.

In operation, the tape is fed through onto the posts of the turret 40 until it occupies the position shown in Figure 4. With the turret held stationary, the knife 70 is operated to sever a label from the tape 51. Because there is a post on each side of the knife 70, both ends of the tape remain attached to the turret after a label has been separated from the tape.

The conveyor belt 30 now advances the bottle 16 located within the turret 40 through the exit end of the turret. As it passes between the two pairs of posts II and IV at the exit end of the turret, the bottle 16 picks up the separated label and removes it from the posts. It is because the bottle may encounter some resistance at this point that it is desirable to provide the second conveyor 32.

As the posts II and IV are, of necessity, wider than the bottle 16, the label will also be longer than the bottle width and its ends will project laterally from the bottle as it is further advanced by the conveyor 30. A pair of pivoted gates 80 serve to wipe these projecting ends of the label to adhere them to the sides of the bottle 16.

At the same time as a bottle leaves through the exit end of the turret 40, another bottle enters through the entrance end. It is to enable these two operations to be combined into one that it is desirable for the turret 40 for carry an even number of pairs of posts. With a fresh bottle lying within the turret 40, the turret is indexed by rotating it through 60 about its vertical axis to place a new label in the path of the next bottle. After the turret has been indexed, the oscillating tensioning arm 60 is operated to feed the tape into the position shown in Figure 4, for the operating cycle described above to be recommenced.

It would be possible to arrange for each length cut from the tape to be slightly longer than two printed labels, thereby ensuring that there will always be one complete label that is readable on the bottle regardless of where the tape is cut. However, for aesthetic reasons and to avoid the need for very small print, it is preferred to avoid such redundancy and to make the length of each printed label the same as the length of tape severed from the supply roll 50 during each operating cycle. In this case, it is important to be able to synchronise the operation of the cutter with the movement of the tape so that the tape is always severed between the borders of adjacent printed labels.

To be able to achieve such correct phasing, it is necessary to detect when the cutting is moving out of phase with the borders of the labels and to adjust the lengths that are cut from the tape to match the length of each printed label.

The position of the borders of the individual labels on the continuous tape can be detected using conventional image analysis and will not therefore be described in detail in the present context. It is possible for example to image a section of the tape carrying an indexing mark onto a simple CCD camera, that need only have one array of cells. The output of such a camera can be analysed to determine if the indexing marks are in advance or in retard of their optimum position and to provide a signal for lengthening or shortening the cut labels to maintain the desired phasing.

As can be seen from Figure 4, the sections of tape extending between adjacent pairs of posts 44 are not taut, slack having been introduced into the tape by the tensioning arm 60. To vary the length of each cut label, it is only necessary to adjust the amount of slack, the slack being increased to lengthen the cut labels and reduced to shorten them. The slack is adjustable by varying the extent to which the tensioning arm 60 penetrates between the two adjacent pairs of posts VI and VIII during each operating cycle and this can be adjusted by altering the stroke or the length of the oscillating arm, or by rotating the motor driving the arm to alter the centre position of the oscillation.

Instead of being oscillated, the arm 60 could be reciprocated radially with respect to the axis of the turret to achieve the same effect and here, once again, one can alter any parameter that affects the extent to which the end of the arm deflects the run of tape between the two adjacent pairs of posts.

Claims

1. A labelling machine comprising a rotatable turret having a plurality of pairs of posts symmetrically disposed about the rotational axis of the turret and extending parallel to said rotational axis, a conveyor for conveying articles to be labelled transversely to the rotational axis of the turret, each conveyed article passing twice between two adjacent pairs of posts of the turret once at an entrance end and once at an exit end of the turret, means for adhering a continuous self-adhesive tape to the posts of the turret lying to one side of the conveyor, means for indexing the turret in synchronism with the movement of the conveyor so as to position a length of the tape in the path of a conveyed article at the exit end of the turret, and means for severing the tape between the posts of one of the pairs of posts straddling the conveyor at the exit end of the turret, the severed length of the tape being transferred to the leading surface of the article to serve as a label as the article is transported by the conveyor between the two pairs of posts at the exit end of the turret.

2. A labelling machine as claimed in claim 1, wherein the articles are supported from below on a horizontal conveyor and their upper ends are steadied by contacting a second conveyor running parallel to and above the main conveyor.

3. A labelling machine as claimed in claim 2, wherein the upper conveyor is formed as three separate sections, the central section disposed between the entrance and exit ends of the turret being driven separately from the sections of the upper conveyor outside the turret.

4. A labelling machine as claimed in any preceding claim, wherein the length of each label is greater than the separation between adjacent pairs of posts on the turret and - 10 - means are provided for varying the slack in the tape as it is adhered to the posts of the turret.

5. A labelling machine as claimed in claim 4, wherein the means for varying the slack in the tape comprise a reciprocating or oscillating arm carrying a tensioning roller that is movable radially with respect to the axis of rotation of the turret between two adjacent pairs of posts on the turret.

6. A labelling machine as claimed in claim 5, wherein the movement or length of the arm is variable in dependence upon a feedback signal from an optical sensor monitoring the position of regularly spaced indexing marks on the tape.

7. A labelling machine constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.