WO2011001216A1

WO2011001216A1 - Buffer device for labelling machines applying self-adhesive labels

Info

Publication number: WO2011001216A1
Application number: PCT/IB2009/052875
Authority: WO
Inventors: James Carmichael; Raffaele Pace
Original assignee: Sidel S.P.A.
Priority date: 2009-07-02
Filing date: 2009-07-02
Publication date: 2011-01-06

Abstract

The present invention relates to a buffer device to be used in labelling machines of the type that apply self-adhesive labels (5) supported by a film (3) onto objects (2), comprising a path for the film (3) defined by a series of fixed guiding and tensioning rollers (6a, …, 6b) that are mounted neutral, and a separating blade (7) for assisting the removal of the labels (5) from said film (3),the buffer device (1)being characterised by the fact that it comprises means for creating loops (30a, 30b) of said film (3) and means that mechanically shorten or lengthen, respectively, the said loops (30a, 30b) with an alternate movement by directly applying to said loops (30a, 30b) a pushing force along a substantially transversal direction with respect to the main direction of advancement of the film (3), as defined by the alignment line (A) of the guiding and tensioning rollers (6a, …, 6b").

Description

"BUFFER DEVICE FOR LABELLING MACHINES APPLYING SELF-ADHESIVE LABELS"

DESCRIPTION

The present invention relates to a buffer device to be used in labelling machines that apply self-adhesive labels to objects, particularly containers.

Labelling machines that remove self adhesive labels from a support film and transfer them onto the surface of containers are known and widespread used. In these machines the containers are carried by a carrousel and come into contact with a labelling unit. In such labelling unit, a reeled support film that carries, on a first portion of it, a plurality of self adhesive labels adhered thereon is delivered, by means of appropriately geared driving systems, to the containers rotating around the carrousel. The application of a label onto the surface of a container consists in its removal from the film by means of a suitable blade or wedge device and its immediate transfer on said surface. The remaining portion of the film, i.e. the one which becomes clear of labels after they have been removed, is rewound onto a recovery roll.

Typically, the driving system comprises a driving roller that moves the film to the containers labelling station, a feeding roll that synchronises the speed of the film to that of the containers and a motor that rewinds the empty portion of the film onto the recovery roll.

While the main carrousel carrying the containers has a continuous motion, the feeding roll and the recovering roll move discontinuously . This is due to the fact that the pitch between the containers on the carrousel is greater than the pitch between the labels on the film, as it is convenient to have the labels adhered close together on the film to save costs, the said support film being very expensive with respect to the labels. It is therefore necessary that the driving system synchronizes the motion of the film to that of the carrousel between the application of a label and the application of the subsequent one and that the removing roll follows the same motion law.

This synchronization causes the formation of a loop of the film between the continuously moving path and the stop and run path, which requires the presence of a buffer device for the part of the film where the loop is formed. In the buffer device, this loop changes its length as the film stops or moves, so that it is normally directed by blowing air into a buffer box for containment. This solution is however expensive, bulky and of difficult maintenance. The current method of using a cyclical feeding motion of the self-adhesive feeding system and its driving system creates high stresses and temperatures in all moving parts. There is a compromise in the design criteria in that the system should have minimum inertia and be driven by maximum force, yet creating large forces from electric motors requires bigger motors with inherently bigger inertia.

It is therefore an object of the present invention to provide a buffer device for a self-adhesive label feeding system that overcomes the above drawbacks, as defined in the appended claims whose definitions are integral part of the present description.

Further features and advantages of the present invention will be better understood from the description of preferred embodiments, which are given below by way of a non-limiting illustration, with reference to the following figures:

Fig. 1 is a schematic sectional plan view of the buffer device according to the invention;

Fig. 2 is a schematic sectional view of the inventive buffer device, along the section II-II' of figure 1 ;

Fig. 3 is a schematic sectional plan view of the inventive buffer device, along the section III-III' of f igure 1 ;

Fig. 4 is a schematic elevational view of another embodiment of the inventive buffer device;

Fig. 5 is a schematic side view of a further embodiment of the inventive buffer device;

Fig. 6 is a schematic elevational view of another embodiment of the inventive buffer device.

With reference to the figures, the buffer device of the invention is indicated with the numeral 1.

The buffer device 1 is positioned along the path of a support film 3, only part of which is shown in the figures, and particularly it is intermediate between a driving roll of a first portion 3a of the film 3, coming from a film reel and carrying self-adhesive labels 5, and a recovery roll that pulls a second portion 3b of the film 3, clear from labels 5 after they have been removed from it, downstream from the point of the application of the labels 5 onto the objects 2 that move around a carrousel 4, to rewind this second portion 3b on a recovery roll (parts not shown) .

In the embodiment shown, the said path for the film

3 comprises a series of six fixed guiding and tensioning rollers 6a, 6a', 6a", 6b, 6b', 6b" that are mounted neutral, and a separating blade 7 for assisting the removal of the labels 5 from the film 3. The said separating blade 7, that is a conventional device in this kind of machines, ends with an acute angle profile 7 ' close to the point of application of a label 5 on an object 2 carried by the carousel 4. During operation, when the film 3 moves around the said profile 7 ' , it is acutely bent so that each label 5 tends to detach, thus presenting its adhesive side towards the object 2 surface that faces it. The object picks up the label 5 and completes its detachment from the film 3.

A first part of said guiding and tensioning rollers 6a, 6a', 6a" is positioned up-stream the said separating blade 7, while a second part of said guiding and tensioning rollers 6b, 6b', 6b" is positioned downstream the separating blade 7. Said rollers 6a, 6a', 6a", 6b, 6b', 6b" are positioned in such a way as to form a substantially rectangular arrangement wherein four rollers 6a, 6a", 6b, 6b" are positioned substantially at the vertexes thereof. In other words, roller 6a' is between rollers 6a and 6a" and roller 6b' is between rollers 6b and 6b", the rollers 6a" and 6b" being the closest ones with respect to the separating blade.

In the embodiment shown, the three rollers 6a, 6a' and 6a" are positioned on a first alignment line Aa, while the three other rollers 6b, 6b' and 6b" are similarly positioned on a second alignment line Ab that is substantially parallel to first alignment line Aa.

Between the rollers 6a and 6a', there is managed a space; a similar space is managed between rollers 6b and 6b' .

Externally with respect to the above mentioned rectangular arrangement and in alignment with the spaces between the two rollers 6a, 6a' that are put up-stream the separating blade 7 and the two rollers 6b that are put down-stream the separating blade 7, the first portion 3a of the film 3 and its second portion 3b, respectively, are caused to form respective loops 30a, 30b, which are intercepted by offset rollers 8a, 8b. The reason why these loops 30a, 30b are formed will be better explained below.

In particular, a first roller 8a is positioned offset with respect to a first and a second guiding and tensioning rollers 6a, 6a' to intercept the first loop 30a that is present on the first portion 3a of the film 3 that is moving toward the separating blade 7 in the direction indicated by the arrow Vl; a second roller 8b is positioned offset with respect to a third and a fourth guiding and tensioning rollers 6b, 6b' to intercept the second loop 30b that is present on the second portion 3b of the film 3 .

Preferably, the film is positioned with respect to the different rollers as shown on figure 1.

The two offset rollers 8a, 8b are mounted neutral on a sliding frame 9, which is disposed inside the above mentioned spaces and whose length is greater than the distance between said alignment lines Aa and Ab, to allow the rollers 8a, 8b to be positioned offset and to define the configuration with the two loops 30a, 30b. The sliding frame 9 can move along a direction line B that is substantially perpendicular to the main direction of movement of the film 3 as defined by the above mentioned alignment lines Aa, Ab . Of course, the sliding direction of the frame 9 can be to some extent different from the perpendicular one, with the provision that the whole movement of the film 3 is not hampered.

The sliding frame 9 thus can oscillate along the said direction line B in the right or left way, as indicated by the arrow V2 in figure 1.

This movement is guided by slide means 10 onto which the sliding frame 9 is mounted and that are anchored to the machine structure 13 (figures 2 and 3) in conventional manner, such as for example by welding or by bolt-and-nut fixing means.

The sliding frame 9 can be in the form of a plate, as represented in figure 1, or have a different frame structure such as the one made up of tubular or bar-like elements. In any case, it is very important that the frame 9 is light and mechanically strong at the same time. To achieve this, the frame 9 can be made of a light material such as aluminium or a synthetic material such as carbon fibre material. The lightness of the frame 9 is important to minimize the inertia of the piece. This is helpful as the frame, during operation, continuously oscillates from the left to the right and vice versa, so that its inertial resistance could worsen the precision of this movement. As will be described below, the precision with which the system works is essential, as a perfect synchronization must be achieved between the feeding of the labels 5 and the circular movement of the objects 2 around the carrousel 4.

In the embodiment of figure 1, and as further detailed in figures 2 and 3, the plate-like sliding frame 9 comprises roller mounting seats 15a, 15b that are positioned close to opposite ends of the frame 9, wherein the said rollers 8a, 8b are arranged. The rollers 8a, 8b are mounted neutral on shafts 16a, 16b fixed in alignment at the sides of the seats 15a, 15b, respectively.

The sliding frame 9 comprises a cam seat 11 having a conjugated profile 12 wherein cam means 14 acts. In the embodiment of figure 1, the cam seat 11 is represented by a slot made on the frame 9 body, wherein the said conjugated profile 12 is fixedly inserted.

The cam means 14 are of conventional type and can be for example a disk cam or a roller cam or the like. Preferably, the cam means 14 will be of the type that subjects the sliding frame 9 to a push-and-pull action. The reactive profile of the cam means 14 in any case will be shaped in such a way to impart the desired motion law to the sliding frame 9.

The cam means 14 are connected to a shaft 17 that is on its turn operatively connected to a motor means 18, such as a servomotor, anchored to the machine structure, which can cause the cam means 14 to rotate, normally at a constant speed.

In different embodiments of the invention, the cam means 14 can be replaced by other means for imparting to the sliding frame 9, which moves along the direction B of figure 1, an alternate motion. For example, such means can comprise linear actuators such as a linear electrical actuator or a pneumatic actuator that are connected to the sliding frame 9 and cause it to slide alternatively in a forward and backward direction, according to a predefined motion law.

In a still different embodiment of the invention, shown in figure 4, the sliding frame 9 carrying the two rollers 8a, 8b is replaced by two fixed cam-shaped rollers 108a, 108b that are positioned each, similarly to the rollers 8a, 8b, between a first couple of guiding and tensioning rollers 106a, 106a' and a second couple of guiding and tensioning rollers 106b, 106b' and externally offset with respect to them. The cam-shaped rollers 108a, 108b are fixed to respective shafts 120a, 120b hinged on the machine structure, that are synchronously rotated by a belt 121 operatively connected to motor means through a gear system (not shown) . In this case, this is the particular shape of the rollers 108a, 108b that causes the loops 30a, 30b of the film 3, to move transversally with a coordinated oscillating movement.

In a further embodiment, shown in figure 5, the sliding frame 9 carrying the two rollers 8a, 8b is replaced by a couple of discs 208a, 208b that are again positioned each, similarly to the rollers 8a, 8b, between two couples of guiding and tensioning rollers 206a, 206a', 206b, 206b' and offset with respect to them. The discs 208a, 208b are fixed to respective shafts (not shown as they are positioned behind the discs in the figure) that are synchronously rotated by a belt 221 operatively connected to motor means through a gear system (not shown) . On the front surface (with respect to figure 5) of each disc 208a, 208b is hinged neutral a plurality of little rollers 222a, 222b, that form a cam-like configuration. In this case too, the film 3 moves along these little rollers 222 a, 222b, so that, as the discs rotate and the rollers 222 a, 222b are arranged in a cam-like configuration, the loop 30a, 30b of the film 3 are caused to move transversally with a coordinated oscillating movement.

The embodiment of figure 6 comprises the same sliding frame 9 and oscillating movement system of the embodiment of figures 1 to 3, so that the corresponding elements are indicated with the same numbering. The difference between such an embodiment and the embodiment of figures 1 to 3 is that the rollers 8a, 8b are replaced by fixed curvilinear elements 308a, 308b positioned at each of the two ends of the sliding frame 9, with their main axis positioned vertical and the convex surface facing outwardly. Such curvilinear elements 308a, 308b are designed to allow the film 3 to slide thereon without causing the labels 5 to detach from the film 3. To this end, the said curvilinear elements 308a, 308b may have a curvature radius sufficiently wide to avoid detachment of the labels and preferably approximate or reproduce a semi-cylindrical profile. Moreover, at least the surface of such curvilinear elements 308a, 308b that is in contact with the film 3 is made of or coated with a material with low friction coefficient (for example, Teflon) , to allow a smooth sliding of the film even at high operational speed.

In all the embodiments described above, the invention provides for a means that operates an acceleration and deceleration of the film 3 motion by shortening or lengthening, respectively, the loops 30a, 30b by directly applying to the said loops 30a, 30b a pushing force along a substantially transversal direction with respect to the main direction of advancement of the film 3, as defined by the alignment lines Aa, Ab of the tensioning rollers 6a, ..., 6b", or 106a, ..., 106b' or 206a, ..., 206b' .

In the most preferred embodiments, such mechanically operated alternate movement of the loops 30a, 30b is obtained by a servomotor means and means for conversion and transmission of the motion to said loops 30a, 30b. More particularly, the said means of conversion and transmission of the motion are of the type that transforms a continuous motion at constant speed to an alternate motion, such as cam means or cam- like means as described above.

Thus, the operation of the inventive device is the following.

As described in the introductory part of the present description, the pitch between the labels 5 on the film 3 is much smaller than the pitch between the objects 2 moving around the carrousel 4. As the carrousel 4 rotates with a constant speed, it is necessary to accelerate or decelerate, or even to start and stop the film 3 to synchronize the application of the labels 5 on the objects 2. While also the feeding and the removing rolls move with a constant speed, the invention consists in a buffer device that receives the first portion 3a of the film 3 from the feeding roll at a constant speed and it is able to decelerate and accelerate it to match the movement of the carrousel 4. At the same time, the second portion 3b of the film 3 deprived of labels 5 is also forwarded to the buffer device of the invention with an accelerated/decelerated movement, so that the inventive device must provide a buffering effect up-stream the rewinding of the second portion 3b by the recovery roll that rotates at a constant speed.

This effect is achieved by creating a loop 30a by means of the roller 8a, 108a, the disk 208a or the curvilinear element 308a, that are offset with respect to the guiding and tensioning rollers 6a, ..., 6b", or 106a, ..., 106b' or 206a, ..., 206b' respectively, and by mechanically lengthening the said loop 30a by sliding the frame 9 toward the loop 30a and along its axis

(right direction in figure 1) or by operating the cam shaped roller 108a or the disc 208a accordingly. In such a way the film 3 is decelerated to allow the label 5 on the film 3 to match the new object 2 arriving on the carrousel 4. Analogously and at the same time, the loop

30b created by the offset roller 8b, 108b or disc 208b is shortened by a backward movement (right direction in figure 1) . While the object 2 is approaching, the film 3 must be accelerated to synchronize with it and this is accomplished by mechanically shortening the loop 30a. To do this, the sliding frame 9 is moved backward (left direction in figure 1) or the cam shaped roller 108a or disc 208a are operated accordingly. At the same time, the frame 9 is moved toward the loop 30b to lengthen it (left direction in figure 1) . This applies a pulling action to the film 3 so that it accelerates as required by the motion law for the application of the label 5.

These operations are repeated for each label 5 applied on an object 2, so that the buffer device 1 allows an alternate movement of the loops 30a, 30b to be accomplished.

The invention further relates to a labelling machine comprising, as a modular or fixed element a labelling station with the buffer device 1 described above, as well as the labelling station as such.

The inventive buffer device achieves the scope of the invention, as it is simple in operation, of low cost and moreover allows avoidance of bulky fan means.

In particular, while avoiding the use of motors operating at discontinuous speed, it improves the maintenance of the device and minimizes inertial problems, so that the precision of the operation is guaranteed.

A further major advantage is the increased speed of label dispensing with this device. By dividing the system into separate parts comprising a high inertia motor running at constant speed, which oscillates a light weight plate via a mechanical cam, the design compromise discussed in the background art can be removed.

In a situation where very high speeds might be required, a combination of cyclical motion by the film feed motor and a complementary cyclical motion by the oscillator frame can potentially get an even greater performance from the system, and reduce stresses in the system at lower speeds, thus increasing the life of the oscillator parts. It will be appreciated that only particular embodiments of the present invention have been described herein, to which those skilled in the art will be able to make any and all modifications necessary for its adjustment to specific applications, without however departing from the scope of protection of the present invention as defined in the annexed claims.

Claims

1. Buffer device for labelling machines of the type that apply self-adhesive labels (5) from a support film (3) onto objects (2), comprising a path for said film (3) defined by a series of fixed guiding and tensioning rollers (6a, ..., 6b"; 106a, ..., 106b'; 206a, ..., 206b') that are mounted neutral, and a separating blade (7) for assisting the removal of the labels (5) from the film (3), characterised in that the said buffer device (1) comprises means for creating loops

(30a, 30b) on said film (3) and means that mechanically shorten or lengthen, respectively, the said loops (30a, 30b) with an alternate movement by directly applying to the said loops

(30a, 30b) a pushing force along a substantially transversal direction with respect to the main direction of advancement of the film (3), as defined by the alignment line (A) of the guiding and tensioning rollers (6a, ..., 6b"; 106a, ...,

106b' ; 206a, ..., 206b' ) .

2. Buffer device according to claim 1, wherein the said means that mechanically shorten or lengthen, respectively, the said loops (30a, 30b) with an alternate movement comprise a motor means and means for conversion and transmission of the motion to said loops (30a, 30b) .

3. Buffer device according to claim 2, wherein the said means of conversion and transmission of the motion are of the type that transforms a continuous motion at constant speed to an alternate motion.

4. Buffer device according to any one of claims 1 to 3, wherein it comprises a first roller (8a) that is positioned offset between a first and a second guiding and tensioning roller (6a, 6a') to intercept the said first loop (30a) , comprised in a first portion (3a) of the film (3) up-stream the said separating blade (7), and a second roller (8b) that is positioned offset between a third and a fourth guiding and tensioning roller (6b, 6b') to intercept the said second loop (30b) , comprised in a second portion (3b) of the film (3) down-stream the said separating blade (7), the said offset rollers (8a, 8b) forming the said means for creating loops (30a, 30b) , wherein the said two offset rollers (8a, 8b) are mounted neutral on a sliding frame (9) .

5. Buffer device according to any one of claims 1 to 3, wherein it comprises a first curvilinear element (308a) that is positioned offset between a first and a second guiding and tensioning roller (6a, 6a') to intercept the said first loop (30a) , comprised in a first portion (3a) of the film (3) up-stream the said separating blade (7), and a second curvilinear element (308b) that is positioned offset between a third and a fourth guiding and tensioning roller (6b, 6b') to intercept the said second loop (30b), comprised in a second portion (3b) of the film (3) down-stream the said separating blade (7), the said offset curvilinear elements (308a, 308b) forming the said means for creating loops (30a, 30b), wherein the said two offset curvilinear elements (308a, 308b) are fixedly mounted at the two ends of a sliding frame (9), with their main axis positioned vertical and the convex surface thereof facing outwardly.

6. Buffer device according to claim 5, wherein at least the surface of said curvilinear elements

(308a, 308b) that is designed to contact the film (3) is made of or coated with a material with low friction coefficient.

7. Buffer device according to claim 4, 5 or 6, wherein the said sliding frame (9) has a length that is greater than the distance between the first couple of guiding and tensioning rollers

(6a, 6a') and the second couple of guiding and tensioning rollers (6b, 6b'), the said sliding frame (9) being caused to move with an alternate motion along a direction line (B) that is substantially transversal to the main direction of movement of the film (3) , as defined by alignment lines (Aa; Ab) of the couples of rollers (6a, 6a'; 6b, 6b') between which the sliding frame (9) is positioned.

8. Buffer device according to claim 7, wherein the said sliding frame (9) is mounted onto slide means (10) and wherein the said sliding frame

(9) comprises a cam seat (11), having a conjugated profile (12), cam means (14) being operatively associated to said conjugated profile (12) to move with an alternate motion the said sliding frame (9) .

9. Buffer device according to claim 8, wherein the said cam means (14) are connected to a shaft (17) that is on its turn operatively connected to a servomotor means (18) that causes the cam means (14) to rotate at a constant speed, the said cam means (14) forming the said means for conversion and transmission of the motion to said loops (30a, 30b) .

10. Buffer device according to claim 8 or 9, wherein the said cam means (14) are disc cam or a roller cam.

11. Buffer device according to any one of claims from 7 to 10, wherein the said sliding frame is made of a light material with high mechanical strength, such as aluminium or carbon fibre material .

12. Buffer device according to claim 7, wherein the said sliding frame (9) is caused to move with an alternate motion along a direction line (B) according to a predefined motion law by means of linear actuators preferably chosen from a linear electrical actuator or a pneumatic actuator .

13. Buffer device according to any one of claims 1 to 3, wherein it comprises a first cam-shaped roller (108a) that is positioned offset between a first and a second guiding and tensioning rollers (106a; 106a') to intercept the said first loop (30a) , comprised in a first portion (3a) of the film (3) up-stream the said separating blade (7), and a second cam-shaped roller (108b) that is positioned offset between a third and a fourth guiding and tensioning rollers (106b; 106b') to intercept the said second loop (30b) , comprised in a second portion

(3b) of the film (3) down-stream the said separating blade (7), the said offset cam-shaped rollers (108a, 108b) forming the said means for creating loops (30a, 30b) as well as the said means for conversion and transmission of the motion to said loops (30a, 30b) .

14. Buffer device according to claim 13, wherein the said cam-shaped rollers (108a, 108b) are fixed to respective shafts (120a, 120b) that are synchronously rotated by a belt (121) operatively connected to motor means through a gear system.

15. Buffer device according to any one of claims from 1 to 3, wherein it comprises a first disc (208a) that is positioned offset between a first and a second guiding and tensioning rollers (206a; 206a') to intercept the said first loop (30a) , comprised in a first portion (3a) of the film (3) up-stream the said separating blade (7), and a second disc (208b) that is positioned offset between a third and a fourth guiding and tensioning rollers (206b; 206b') to intercept the said second loop (30b) , comprised in a second portion (3b) of the film (3) down-stream the said separating blade (7), and wherein on the said offset discs (208a, 208b) are hinged neutral a plurality of little rollers (222a; 222b) , that form a cam-like configuration, wherein the said offset discs (208a, 208b) form the said means for creating loops (30a, 30b) as well as the said means for conversion and transmission of the motion to said loops (30a, 30b) .

16. Buffer device according to claim 15, wherein the said discs (208a, 208b) are fixed to respective shafts that are synchronously rotated by a belt (221) operatively connected to motor means through a gear system.

17. Labelling machine comprising as a modular or fixed element, a buffer device as claimed in any one of claims from 1 to 16.