LABELLING UNIT AND METHOD FOR LABELLING CONTAINERS

Abstract

A labelling unit and a method for labelling containers is provided. Said method provides rapid and reliable switching movements with low noise development and low wear of the mechanical components in that suction bars for suctioning label areas at places where container gaps occur can be actively switched back to an inner position, in which they do not come into contact with a gluing unit, and in that the switching process is triggered with the aid of a stationary toggle lever.

Claims

1. A Labeling unit, comprising: a vacuum transfer cylinder with suction bars for suctioning labels; a gluing unit formed adjacent to said vacuum transfer cylinder for applying glue onto said labels; and a stationary switching unit having a movable operating cam for switching said suction bars to an inner position where said suction bars pass said gluing unit without contacting it, wherein said stationary switching unit comprises a toggle lever for actuating said moveable operating cam.

2. The labeling unit according to claim 1, where said stationary switching unit is configured such that it switches back said suction bars by extending said toggle lever to said inner position.

3. The labeling unit according to claim 1, where end-side mounting points of said toggle lever are coupled to oppositely displaceable carriages and said moveable operating cam is connected to one of said end-side mounting points.

4. The labeling unit according to claim 1, where said operating cam is displaceably mounted for actuation.

5. The labeling unit according to claim 1, where control rollers connected to said suction bars are formed on said vacuum transfer cylinder in order to switch said suction bars to the inner position when they pass said operating cam.

6. The labeling unit according to claim 1, where an electrical or pneumatic switching drive, connected to a center mounting point of said toggle lever, is formed on said switching unit.

7. The labeling unit according to claim 1, where said suction bars are formed in pairs for a front area and an end area of said labels.

8. The labeling unit according to claim 7, where a first switching unit for leading suction bars for suctioning said front area and a second switching unit for trailing suction bars for suctioning said end area are formed.

9. A labeling machine with said labeling unit according to claim 1, a continuously rotatable labeling carousel for containers, and a monitoring device formed upstream of said labeling unit for detecting position gaps between incoming containers.

10. A method for labeling containers, in which labels are transferred to a vacuum transfer cylinder, attached there by way of suction bars and by the suction bars brought into contact with a gluing unit, where suction bars selectively not being charged with labels are switched back to an inner position in such a manner that said suction bars pass said gluing unit without contacting it, wherein an actuating force for switching back said suction bars is transferred to said suction bars by way of a stationarily mounted toggle lever.

11. The method according to claim 10, where an inflow of said labels to said vacuum transfer cylinder is interrupted in correspondence with a position gap in an inflow of containers.

12. The method according to claim 10, where said suction bars are switched back during the continuous rotation of said vacuum transfer cylinder.

13. The method according to claim 10, where said suction bars are switched back by extending said toggle lever against a spring force that returns said suction bars to an outer position.

14. The method according to claim 10, where the inflow of containers to be labeled is further monitored for position gaps, and said suction bars are selectively switched back in response to position gaps thus detected.

15. The method according to claim 10, where said suction bars are switched back in a region of a position gap between labels.

Description

[0028] A preferred embodiment of the invention is illustrated in the drawings, where

[0029] FIG. 1 shows a schematic top view of a labeling unit;

[0030] FIG. 2 shows a view of a vacuum transfer cylinder from below;

[0031] FIG. 3 shows an inclined view of two switching units; and

[0032] FIG. 4 shows a longitudinal sectional view through a switching unit in two switching positions.

[0033] As can be seen from FIG. 1, labeling unit 1 in a preferred embodiment comprises a vacuum transfer cylinder 2 and a gluing unit 3 which is formed to be stationary in the periphery of vacuum transfer cylinder 2 Schematically indicated are further a conveying roller 4 and a cutting unit 5 with which labels 6 are separated from a label strip 7 provided endlessly from a reel in a known manner and transferred to vacuum transfer cylinder 2. Labels 6 are suctioned at vacuum transfer cylinder 2 in the manner described below and for continuous labeling are successively brought into contact with a glue roller 3a formed on gluing unit 3 for applying glue. Labels 6 with the glue applied are then transferred in the region of a continuously rotatable container carousel 8 in a manner known per se to containers 9 to be labeled.

[0034] Labeling unit 1 and labeling carousel 8 are part of a labeling machine 10 which is formed in a lateral body region, for example, for fully labeling containers 9 that are clamped in a centered manner on turntables 8a.

[0035] As can be seen from FIG. 2, vacuum transfer cylinder 2 comprises suction bars 11 which are formed, for example, in pairs in the form of leading suction bars 11a and trailing suction bars 11b for front and rear areas 6a, 6b of labels 6. All suction bars 11 are during normal labeling operation by way of compression springs 12 or the like [sic: held] in an outer position 13a in which suction bars 11 each guide held sections 6a, 6b toward glue roller 3a.

[0036] Suction bars 11 can be selectively switched back to an inner position 13b in which suction bars 11 each pass glue roller 3a without contacting it. At least one stationary switching unit 14 with an operating cam 15 that is displaceable thereon is formed for actively switching back suction bars 11.

[0037] The at least one operating cam 15 can be actuated, preferably by lateral displacement, so that control rollers 16 attached to vacuum transfer cylinder 2 perform a switching movement when passing operating cam 15, which they each transmit mechanically to a suction bar 11 drive-coupled thereto.

[0038] As can be seen from FIG. 3, a first switching unit 14a is preferably formed with a first operating cam 15a for switching the leading suction bars 11a and a second switching unit 14b with a second operating cam 15b for switching trailing suction bars 11b. Control rollers 16 for leading suction bars 11a and control rollers 16 for trailing suction bars 11b preferably run along (schematically indicated) separate partial circles 16a, 16b.

[0039] As can be seen from FIG. 4, the at least one switching unit 14 preferably comprises an electromagnetic or hydraulic switching drive 17 and a toggle lever 18 driven by the latter and attached with its end side mounting points 18a, 18b to oppositely movable carriages 19a, 19b. A first carriage 19a is connected to a carrier plate 20 which is used for mounting operating cams 15. First carriage 19a performs a (schematically indicated) linear movement 20a together with carrier plate 20 when suction bar 11 is switched back. A second carriage 19b performs an oppositely directed linear movement 19c.

[0040] Both carriages 19a, 19b are linearly guided in a known manner in switching unit 14. In this way, the switching movement of end-side mounting point 18a is transmitted directly to carrier plate 20 and operating cam 15. This minimizes the mass to be moved during switching. In principle, however, it would also be conceivable to indirectly convert the switching movement of end-side mounting point 18a to a pivot movement of operating cam 15.

[0041] At position I, FIG. 4 illustrates that toggle lever 18 is extended to its inner position 13b when suction bars 11 are switched back. Accordingly, position II of FIG. 4 illustrates that toggle lever 18 is increasingly angled when suction bars 11 are switched forwardly to their outer position 13a. It then arises from the operating principle of the toggle lever that end-side mounting point 18a, and thus operating cam 15, first moves relatively rapidly when being switched back, and that the actuation force at end-side mounting point 18a increases with an increasingly extended toggle lever 18. Suction bars 11 can therefore be switched equally rapidly and reliably to inner position 13b against a spring force or the like that restores suction bars 11 to outer position 13a.

[0042] Switching drive 17 is preferably designed as a linear drive with a plunger 17a or the like which is drive-coupled to a center mounting point 18c of toggle lever 18. Switching drive 17 is then controlled by a (schematically indicated) control unit 21 for respectively actively extending or angling toggle lever 18. In principle, however, it would also be possible to couple the center mounting point 18c to an output shaft of the switching drive by way of a connecting rod or the like (not shown).

[0043] Control unit 21 is connected to a monitoring unit 22 that is formed upstream of vacuum transfer cylinder 2 and monitors the flow of containers and, upon the occurrence of position gaps 23 in the flow of containers (in FIG. 1 indicated by a missing container 9 illustrated by dots), transmits corresponding measurement or control signals to control unit 21. The latter in turn selectively creates corresponding position gaps 24 between labels 6 transported at vacuum transfer cylinder 2, for example, by actuating conveying roller 4 and cutting unit 5, and causes the at least one switching unit 14 to switch back suction bars 11 which are not charged with labels 6 at selective position gaps 24.

[0044] Labeling unit 1 can be operated, for example, as follows:

[0045] During normal labeling operation of labeling unit 1, label strip 7 is preferably fed continuously by way of conveying roller 4 to cutting unit 5 and separated therein to form labels 6. Labels 6 are transferred from cutting unit 5 to vacuum transfer cylinder 2 which rotates continuously in one direction 2a. Each label 6 is suctioned, preferably at its front end 6a and at its rear end 6b, by a leading suction bar 11a and a trailing suction bar 11b and at a respective intermediate area. Suction bars 11 are then in their normal outer position 12, so that the front and rear end areas 6a, 6b are each brought into contact with glue roller 3a and are in this manner coated with hot glue or the like.

[0046] The rotational speed of vacuum transfer cylinder 2 is synchronized in a manner known per se with the transport speed of containers 9 on continuously rotating labeling carousel 8, so that a respective label 6 is transferred to each container 9. Containers 9 are there rotated in an upright position on turntables 8a in a known manner and labels 6 are, in particular, fully circumferentially wound onto containers 9 and glued on with their end areas 6a, 6b where glue was applied.

[0047] The incoming flow of containers 9 is continuously examined with the aid of monitoring unit 22 with regard to the occurrence of position gaps 23, i.e. with regard to missing containers 9, for example, by way of optical scanning. If a position gap 23 is detected in the flow of containers, then monitoring device 22 sends a suitable signal to control unit 21 which causes, for example, conveying roller 4 to interrupt the advancement of label strip 7. Consequently, cutting unit 5 can temporarily pass no label 6 to continuously rotating vacuum transfer cylinder 2. A position gap 24 in the flow of labels corresponding to position gap 23 in the flow of containers is thus created.

[0048] In order to prevent gluing unit 3 from applying glue to suction bars 11 that are not charged with a label 6 in the region of the corresponding position gap 24, the respective suction bars 11 are actively switched back to their inner position 13b by actuating switching units 14 while extending the toggle lever 18 and displacing operating cams 15 by way of control rollers 16 passing therealong.

[0049] Once control rollers 16 associated with position gap 24 have left the region of operating cams 15, and thus the working area of gluing unit 3, the switched back suction bars 11 automatically return to their outer position 13a by way of spring tension or the like.

[0050] At the end of position gap 24, operating cams 15 are switched with the aid of switching units 14 by angling toggle lever 18 such that control rollers 16 pass by without effect. Consequently, subsequent suction bars 11 remain in their normal working position, i.e. in outer position 13a, so that suctioned labels 6 are properly applied glued and transferred to containers 9.

[0051] The number of suction bars 11, switching units 14 and operating cams 15 described is by way of example and could be adapted to required machine performance, device dimensions or the like, without parting from the underlying switching principle by use of toggle lever 18.

[0052] Transporting label strip 7, separation it to form labels 6 and transporting and transferring those to vacuum cylinder 2 can be done in a known manner.