Vacuum drum for a labeling unit, and labeling unit comprising a vacuum drum of this type

Abstract

A labeling apparatus includes a rotating vacuum drum and a pair of vacuum holders on the drum that are switched by rotating switches between a working position for gluing labels and a rest position in which the vacuum holders avoid an application of glue. Actuators cause the switches to transition between operating positions. Stationary switch controllers initiate transitions between the operating positions of the switch, thereby causing the holders to transition between their two positions.

Claims

1. An apparatus comprising a drum that rotates in a direction-of-rotation about an axis thereof, said drum being a vacuum drum, a holder pair that rotates with the drum, said holder pair comprising vacuum holders that are disposed at a peripheral surface of said drum and that are offset relative to each other along said drum's direction of rotation, wherein said vacuum holders comprise a leading holder that holds a leading edge of a label for labeling a container and a trailing holder that holds a trailing edge of said label, rotating switches that transition between operating positions, switch actuators that cause said rotating switches to transition between said operating positions, and switch controllers that engage said switch actuators to initiate transitions between said operating positions, thereby causing said holders to transition between a rest position, in which said holders are held at a position that avoids application of glue on said label, and a working position, in which said holders are held so as to promote application of glue on said label held by said pair, said switch controllers being stationary, and wherein said rotating switches each comprise a U-shaped carrier having side limbs connected by a base limb, an axle that rotates about an axis that is parallel to said drum's axis, and rocker levers disposed along said axle.

2. The apparatus of claim 1, further comprising segments, wherein said pair of holders is one of a plurality of pairs of holders, wherein each of said segments supports one of said pairs of holders, wherein said plurality of pairs comprises a first pair and a second pair, wherein said first pair is configured to be switched between rest and working positions independently of said second pair.

3. The apparatus of claim 1, wherein said apparatus further comprises a front pad and a rear pad, wherein said front pad is on said leading holder and said rear pad is on said trailing holder, wherein said rotating switches comprise front and rear rotating switches that cause said leading and trailing holders, respectively, to transition between said rest position and said working position.

4. The apparatus of claim 1, further comprising a front nozzle body, a rear nozzle body, a first vacuum pad, and a second vacuum pad, said first vacuum pad being disposed on said front nozzle body and said second vacuum pad being disposed on said rear nozzle body, wherein said rotating switches each comprise side limbs connected by a base limb, a rotatable axle that is parallel to said drum's axis, rocker levers disposed along said axle, and spring-loaded plungers that are biased for movement parallel to said base limb, wherein each of said rocker levers comprises first and second switching surfaces for engaging a first end of said plunger, wherein each of said plungers comprises a second end that is connected to a nozzle body selected from the group consisting of said front nozzle body and said rear nozzle body.

5. The apparatus of claim 1, wherein said rotating switches each comprise a pivot axle and rocker levers securely arranged on said pivot axle so as to pivot between said operating positions, wherein each of said rocker levers comprises a first switching surface and a second switching surface, wherein transitioning between said operating positions occurs as a result of said rocker levers pivoting to-and-fro between said operating positions such that engaging said first switching surface and disengaging said second switching surface causes a transition between said operating positions.

6. The apparatus of claim 1, further comprising front and rear vacuum pads disposed at said holders, wherein said rotating switches each comprise rocker levers, wherein transitioning between said operating positions occurs as a result of pivoting said rocker levers, wherein pivoting said rocker levers results in transitioning said front and rear vacuum pads of a holder between being held in said working position and being held in said rest position.

7. The apparatus of claim 1, further comprising a base carrier that defines a plane perpendicular to said drum's axis, wherein said rotating switches comprise front and rear rotating switches for said leading and trailing holders respectively, wherein said switch actuators comprise a front switch actuator for actuating said front rotating switch and a rear switch actuator for actuating said rear rotating switch, wherein said front and rear switch actuators comprise free ends that are different distances from said base carrier.

8. The apparatus of claim 1, wherein each of said switch controllers comprises a pivotable lever having a control surface for interacting with a switch actuator to cause said transition between said operating positions.

9. The apparatus of claim 1, wherein said switch controllers comprise first, second, and third switch controllers, each of which comprises a pivotable lever and a control surface on said lever and wherein said third controller comprises two control surfaces.

10. The apparatus of claim 1, wherein said switch actuators comprises a first switch actuator, wherein said switch controllers comprise a first switch controller that has a control surface that presses against said first switch actuator in a radially inward direction as said first switch actuator rotates with said drum past said first switch controller, thereby displacing said first switch actuator in a radially inward direction so as to cause said leading vacuum holder to transition into said rest position.

11. The apparatus of claim 1, wherein said switch actuators comprise first and second switch actuators, wherein said switch controllers comprise first and second switch controllers, wherein said first and second switch controllers comprise control surfaces that press against said first and second switch actuators, respectively, in a radially inward direction as said first and second switch actuators rotate with said drum past said first and second switch controllers, thereby displacing said first and second switch actuators in a radially inward direction so as to cause said leading vacuum holder and said trailing vacuum holder to transition into said rest position.

12. The apparatus of claim 1, wherein said switch actuators comprise first, second, and third switch controllers, wherein said first and second switch controllers engage corresponding first and second switch actuators to thereby cause said leading holder and said trailing holder to transition into said rest position and wherein said third switch controller comprises first and second control surfaces that press against said first and second actuators, respectively, in a radially outward direction away from said drum's axis thereby causing said leading holder and said trailing holder to transition into said working position.

13. The apparatus of claim 1, further comprising a labeling machine, wherein said drum is a constituent of said labeling machine, and wherein said labeling machine is configured to draw labels off a roll-fed label and comprises a cutter to cut labels from said roll-fed label, said labels having a length that corresponds to a distance between said leading and trailing holders.

14. The apparatus of claim 1, wherein said vacuum drum is bistable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features of the invention will be apparent from the following detailed description and the accompanying figures, in which:

(2) FIG. 1 is a top view of a labeling machine.

(3) FIG. 2 is an oblique view from above a vacuum drum in the labeling machine of FIG. 1;

(4) FIG. 3 is an oblique view from below the vacuum drum in the labeling machine of FIG. 1;

(5) FIG. 4 is a view from above a carrier plate of the vacuum drum shown in FIGS. 2 and 3;

(6) FIG. 5 is a side view of the vacuum drum in FIGS. 1-3;

(7) FIG. 6 is a segment of the vacuum drum shown in FIGS. 1-5.

(8) FIG. 7 is a sectional view of the segment shown in FIG. 6;

(9) FIG. 8 is a view from above the segment shown in FIGS. 6 and 7 with a front vacuum holder in its working position; and

(10) FIG. 9 is a view from above the segment shown in FIGS. 6 and 7 with a front vacuum holder in its resting position.

(11) In the figures identical reference numbers are used for elements of the invention which are the same or have the same effect. Moreover, for easier overview, in the individual figures only reference numbers are represented which are required for the description of the respective figure. The invention is also represented in the figures only in schematic views in order to explain the method of working. In particular, the representations in the figures serve only to explain the underlying principle of the invention. For reasons of easier overview, the representation of all the constituent parts of the device has been refrained from.

DETAILED DESCRIPTION

(12) FIG. 1 shows a rotor 7 that rotates in a rotor direction “A” as it carries containers 2 past a labeling machine 1. The rotor 7 includes rotary plates 8 disposed along its circumference. These rotary plates 8 form standing surfaces for containers 2 that are brought in via a container inlet. Each container 2 stands on a rotary plate 8.

(13) The labeling machine 1 includes a gluing unit 11, a vacuum drum 6, and a cutter 5.

(14) The gluing unit 11 applies glue on the rear side of each label 3 as it is being held at the circumference of the vacuum drum 6. As the rotor 7 carries the container 2 past the labeling machine 1, the label's leading end 3.1, which has been coated with glue, is transferred to the moving container 2. The rotary plate 8 rotates the container 2 to wind the rest of the label 3 onto the container 2. After having been thus labelled, the container 2 is conveyed away for further processing.

(15) The cutter 5, which includes a cutting drum 12, cuts a length of label material 3a that has been drawn from a storage roll 4 by conveyor rollers at a rate that depends on the rotor's rotational speed. The length that is cut by the cutter 5 is that needed for a label 3.

(16) The vacuum drum 6 rotates in a vacuum-drum rotation direction “B” about its axis TA, best seen in FIG. 2. The cutting drum 12 rotates in a cutting-drum rotation direction “C” that is opposite the vacuum-drum rotation direction “B.” The vacuum drum 6 transfers these labels 3 onto the containers 2 as the rotor 7 carries the containers 2 past the labeling machine 1.

(17) FIG. 2 shows the vacuum drum 6 and its axis TA. The vacuum drum 6 is a transfer drum that comprises identical segments 17. Each segment 17 of the vacuum drum 6 comprises a holder pair 6 having a leading holder 9.1 and a trailing holder 9.2, both of which are vacuum holders that hold by using suction provided by a vacuum source. The holders 9.1, 9.2 are offset from each other along the vacuum-drum's rotation direction B by an amount that corresponds to the label's length. The leading holder 9.1 holds the label's leading end 3.1 and the trailing holder 9.2 holds the label's trailing end 3.2.

(18) FIG. 3 shows vacuum pads 35.1, 35.2 disposed over corresponding vacuum holders 9.1, 9.2. Each vacuum pad 35.1, 35.2 is a strip having a long axis parallel to the drum's axis TA. The vacuum pads 35.1, 35.2 project slightly over the drum's peripheral surface. This projection causes the gluing station 11 to apply glue only to the label's leading end 3.1 and its trailing end 3.2.

(19) The vacuum pads 35.1, 35.2 each form a hermetically tight seal with a corresponding nozzle body 36.1, 36.2, as shown in FIG. 6. Suction lines 22 then connect openings 10 behind the vacuum pad 35.1, 35.2 to a central vacuum source via a rotary connection. This provides the vacuum needed to hold a label 3.

(20) In operation, switch actuators 31.1, 31.2 cause rotating switches 30.1, 30.2 to transition first and second operating positions BS1, BS2, which can be seen in FIGS. 8 and 9. The switch actuator 31.1, 31.2 is a rotationally symmetric structure that extends longitudinally along an axis. An example of a switch actuator 31.1, 31.2 is bolt.

(21) A transition of the rotating switch 30.1, 30.2 causes its corresponding leading or trailing holder 9.1, 9.2 to transition between an rest position WP, shown in FIG. 9, and an working position AP, shown in FIG. 8. The first operating position BS1 results in the rest position WP and the second operating position BS2 results in the working position AP.

(22) The rest position WP is radially inward relative to the working position AP. As a result, a holder 9.1, 9.2 that is in its rest position WP avoids contact with the gluing unit 11. In contrast, a holder 9.1, 9.2 that is in its working position AP causes the label 3 being held to come into contact with the gluing unit 11.

(23) The working position AP is the holder pair's ordinary working position. It is used when there is a container 2 to be labelled. When in its working position AP, the holder pair 9 guides the label against a gluing unit 11, which can be seen in FIG. 1.

(24) The rest position WP, which is located radially inwards relative to the outer working position AP, is the holder pair's diversion position. This rest position WP is used when a holder pair 9 is not holding a label 3 or when there is no container 2 to label as a result of a gap in container flow.

(25) This ability to switch between rest position WP and working position AP is useful for accommodating a gap in container flow. In particular, if there is no container 2 to be labelled because of a gap in container flow, there is little sense in applying glue to a label being held by the vacuum drum 6. As a result, the drum 6 is configured to be switched into its rest position WP at the beginning of a gap in container flow and to be switched back into its working position AP at the end of that gap.

(26) As shown in FIG. 3, each segment 17 includes a floor defined by a carrier plate 15. The carrier plate 15 is shaped like a sector of a circle. A vertical drive shaft 16, best seen in FIG. 2, passes through a stationary base carrier 40 and connects to the segments 17. A motor 18 that is secured to the underside of the base carrier 40 drives the drive shaft 16. A suitable drive 18 is an electric motor, and in particular, a servomotor.

(27) It is the segment's carrier plate 15 that supports the holder pair 9. A segment wall 19 between the leading holder 9.1 and the trailing holder 9.2 forms the vacuum drum's peripheral surface. FIG. 3 shows suction openings 20 on the segment wall 19. These suction openings 20 connect to a radially-inward vacuum chamber 21 via suction lines 22, as shown in FIG. 6. A rotational connection, which is not shown, ultimately connects to a centralized vacuum source.

(28) As shown in FIG. 6, a rotating switch 30.1, 30.2 comprises a U-shaped carrier element 32 having a pair of side limbs and a base limb connecting the side limbs. An axle 33, which is parallel to the drum axis, extends between these side limbs.

(29) Upper and lower rocker levers 34.1, 34.2 are disposed along the axle 33. At a radially-inward end thereof, the rocker levers 34.1, 34.2 engage the axle 33. At their radially-outward ends, the rocker levers 34.1, 34.2 engage corresponding spring-loaded plungers 37 that are biased in a radially-inward direction to push the rocker levers 34.1, 34.2 into the axle 33.

(30) As can be seen in FIG. 8, each rocker lever 34.1, 34.2 comprises first and second switching surfaces SF1, SF2, one of which is in engagement with the plunger 37. The operating position BS1, BS2 depends on which one of the surfaces SF1, SF2 engages the plunger 37.

(31) The first operating position BS1 occurs when rocker lever's first switching surface SF1 engages the plunger 37. This causes the associated vacuum pads 35.1, 35.2 to be held securely in the rest position WP. The second operating position BS2 occurs when second switching surface SF2 engages the plunger 37. This causes the associated vacuum pads 35.1, 35.2 to be held securely in the working position AP.

(32) Referring now to FIG. 6, each pivot axle 33 connects to a lever 39. Turning this lever 39 changes the state of its corresponding switch actuator 31.1, 31.2.

(33) FIG. 4 shows stationary switch-controllers 41.1, 41.2, 41.3 that are mounted to the base plate 40. A stationary switch controller 41.1, 41.2, 41.3 engages the lever 39, thereby rotating the pivot axle 33 and thus causing a change in which switching surface SF1, SF2 engages the plunger 37. This causes radially outward or inward movement that then causes the rotating switch 30.1, 30.2 to transition between its first and second fixed stationary operating positions BS1, BS2.

(34) Because the plunger 37 is spring loaded, the rotating switch 30.1, 30.2 remains in its last assigned operating position BS1, BS2 without the need for a switching force or retaining force from the associated switch actuator 31.1, 31.2 by way of the stationary switch controllers 41.1 . . . 41.3. The rotating switches 30.1, 30.2 are thus bistable switches.

(35) The vacuum drum 6 is thus a bistable system that can stay in its inner rest position WP or its outer working position AP without any external force. The only force required is that for a switching event associated with changing state. These switching events occur at the beginning or end of a gap in the container flow. The number of switching events is thus related to the number of gaps of missing containers rather than the number of missing containers. This reduces the number of switching events, and hence reduces noise and wear.

(36) Referring now to FIG. 7, in some embodiments, free ends of the switch actuators 31.1, 31.2 are at different heights above the base carrier 40. In particular, the free ends of the front switch actuators 31.1 of the front vacuum holders 9.1 lie in a first plane and the free ends of the rear switch actuators 31.2 of the rear vacuum holders 9.2 lie in a second plane. The first and second planes are parallel to the plane of the base carrier 40 but at different heights H1, H2 above the base carrier 40. In particular, the first plane is further from the base carrier 40 than the second plane. Therefore, the free ends of the front switch actuator 31.1 are above the free ends of the rear switching elements 31.2.

(37) To cause a switching event, the switch actuator 31.1, 31.2 is brought into working engagement with at least two switch controllers 41.1, 41.2, 41.3. As shown in FIG. 4, each switch controller 41.1, 41.2, 41.3 comprises a pivotable lever 42.1, 42.2, 42.3 and a control surface 43.1, 43.2, 43.3 for initiating a switching event between operating positions BS1, BS2.

(38) The first switch controller 41.1 is configured such that, as the front switch actuator 31.1 of a corresponding leading holder 9.1 travels past it, the first switch controller's control surface 43.1, which is at the height H1, presses the front switch actuator 31.1 radially-inward towards the drum's axis TA. This switches the front rotating switch 30.1 into the first stationary position BS1. This puts the leading holder 9.1 into the rest position WP.

(39) As the drum 6 continues to rotate, the front switch actuator 31.1 comes out of engagement with the first control surface 43.1. However, the leading holder 9.1 remains in the rest position WP.

(40) The second switch controller 41.2 presses the rear switch actuator 31.2 of a corresponding trailing holder 9.2 as it rotates about the drum's axis TA. In particular, the second control surface 43.2, which is at the height H2, presses radially inward towards the drum's axis TA to cause the rear rotating switch 30.2 to transition into the first operating position BS1, thus placing the trailing holder 9.2 into the rest position WP. Because the switch is bistable, further rotation of the rear switch actuator 31.2 does not change the trailing holder's position.

(41) The third controller 41.3 is configured in this situation such as to press the front and rear switch actuator 31.1, 31.2 of corresponding leading and trailing holders 9.1, 9.2 as they rotate with the drum 6 past the third controller 41.3. The third controller 41.3 features a first control surfaces 43.3 that is located at a distance H1 above the base 40 and a second control surface 43.4 that is located at a distance H2 above the base 40. The first and second control surfaces 43.3, 43.4 of the third controller 41.3 press radially outward in a direction away from the drum's axis TA. This causes the rotating switches 30.1, 30.2 to be switched into the second stationary operating position BS2, in which the leading and trailing holders 9.1, 9.2 are in the working position AP. As the drum 6 continues to rotate, the actuators 31.1, 31.2 come out of engagement with the control surfaces 43.3, 43.4. However, the leading and trailing holders 9.1, 9.2 nevertheless remain in the same position.

(42) In this situation, the switch controllers 41.1 . . . 41.3 are configured so as to be switchable separately from one another.

(43) Having described the invention and a preferred embodiment thereof, what is claimed as new and secured by letters patent is: