FR2602484A1 - SCRUB OR STICK DEVICE FOR APPLYING ADHESIVE TO SHEETS OF PACKAGING MATERIAL - Google Patents

Abstract

A. SCRUB OR GLUE DEVICE FOR APPLYING ADHESIVE TO SHEETS OF PACKAGING MATERIAL. B. DEVICE CHARACTERIZED IN THAT IT INCLUDES MANEUVERING MEANS42, 43 INTENDED TO CONTROL THE MOVEMENT OF THE SCRAPER ELEMENT 32, 33 WITH RESPECT TO THE SCRUB ELEMENT 30, 31. C. THE INVENTION CONCERNS A DEVICE SCRUB OR SIZE FOR APPLYING ADHESIVE TO SHEETS OF PACKAGING MATERIAL.

Description

"Exfoliating or gluing device for applying an adhesive to

  The invention relates to a device for applying an adhesive to sheets of packaging material, more particularly the invention relates to a scrubbing or gluing device for applying an adhesive to virgin sheets. cardboard

  used in a packaging machine.

  The known gumming or gluing devices of the above type comprise a pair of counter-rotating rollers, referred to respectively as the scrub roller and the pressure roller, arranged substantially tangentially to each other along a common generative line. located along the path in a straight line followed by the virgin leaves. The scrubbing roll is often constituted by a number of cylindrical coaxial scrub disks spaced along the distance between the given portions of the blank sheets to be coated with adhesive. These discs are partially immersed in a container containing rubber or glue, and have on their respective cylindrical surfaces grooves for providing the adhesive on the given portions of the blank sheets. Fixed doctoring means 25 are used to clean the cylindrical surfaces

  scrubbing discs, so that only the rubber

  held inside the grooves be applied by the

  discs on the given parts of the blank sheets.

  In actual practice, however, and despite the careful and precise assembly between the scraper means and the scrubbing roll, a thin film of adhesive inevitably attaches to the entire cylindrical surface of the scrub discs, due to a minimum clearance left between the stationary scrapers and the surface of the scrub discs, a minimum clearance below which the wear of the scrapers and scrub discs would no longer be tolerable. As a result, the blank sheets are also covered by the scrubbing device of a thin film of adhesive outside the intended portions, which leads to a number of disadvantages. One of these disadvantages is that packets made using these blank sheets which often consist of a number of superimposed sheets of packaging material, may be defective because the sheets stick to each other or to each other. the contents of the package. Another disadvantage is that this clogging of the virgin sheets leads to serious fouling of the packaging line elements of the packaging machines equipped with them.

  scrubbing devices of the type above.

  On another known type of scrubbing device, the scrub discs have projections or peripheral sectors whose peripheral surfaces correspond to the shape and position of the tampons.

  gum to be applied to the blank sheets as they pass between the scrub disks and the pressure roller.

  The scrubbing device includes stationary scraper means formed to shave the front and side surfaces of the sectors to remove excess adhesive as the scrub discs rotate. However, the scraping means can not prevent a certain amount of adhesive from attaching to the surfaces defining the sectors upstream and downstream of the direction of rotation of the scrubbing discs, which eventually leads to an accumulation of adhesive on these: surfaces. It inevitably results in the sectors applying gum pads on the blank sheets outside the given parts of these sheets which

  are intended to be covered with adhesive.

  Such a scrubbing device therefore requires frequent cleaning and therefore frequent stops of the packaging machine to maintain the

  above disadvantages within acceptable limits.

  The object of the invention is to provide a scrubbing device designed to eliminate or, in some cases, eliminate at least the majority of the above disadvantages typically associated with known scrubbing devices.

types above.

  To this end, the invention relates to a gumming or gluing device for applying an adhesive to sheets of packaging material such as, in particular, blank sheets of cardboard successively fed to a packaging machine; this device comprising a rotary scrubbing or gluing member adapted to extract the adhesive from a container and transferring it onto the blank sheets in the form of buffers occupying given positions on this blank sheet, the scrubbing element having , on its peripheral surface, projections intended to apply the buffers on the virgin leaves; and comprising at least one scraper element positioned upstream of the point where the adhesive is applied to the blank sheets, and adapted to remove excess adhesive on the outer surface of the scrubbing member; characterized in that it comprises operating means for controlling the displacement

  of the scraper element with respect to the scrubbing element.

  Other improvements are characterized in that the scrub member comprises a number of scrub discs supported and driven by a common shaft; a scraper element being associated with all the scrubbing discs and being connected to and actuated by a single cam member forming part of the operating means; a number of scrub discs supported and driven by a common shaft; a scraper member being associated with each of the scrubbing discs 10 and being connected to and actuated by a corresponding cam member forming part of the operating means; the scraper member is moved by the respective cam member according to the profile of the respective scrubbing disc; the cam means are mounted on a supporting shaft and driving the scrubbing member; on each of the disks

  each projection is connected to the next projection by a surface having no sharp edges.

  The invention will be described in detail, by way of non-limiting example, with reference to the accompanying drawings in which: - Figure 1 shows a blank sheet of cardboard intended to receive, on given parts thereof an adhesive from a scrubbing device according to the features of the invention; - Figure 2 shows a schematic view of the device according to the invention, in section along the line II-II of Figure 4; - Figure 3 shows a view of the device according to the invention, in section along the line III-III of Figure 2; - Figure 4 shows a view of the device according to the invention in section along the line IV-IV of Figure 2; and FIG. 5 represents a schematic plan view of a variant of the device represented on FIG.

Figures 1 to 4.

  Reference I of FIG. 1 denotes a blank sheet of cardboard in which a given product is to be packed. For example, in the

  following description, this product consists of a group of cigarettes (not shown) to be packaged

  in the blank sheet 1 to form a pack of cigarettes

rigid package type.

  References 2, 3 and 4 denote parallel gum pads of different shapes and sizes applied to given portions of blank sheet 1 by a gumming device generally identified by reference numeral 5 and shown in FIGS. 4. In more detail, references 2, 3 and 4 indicate respective sets of three gum pads applied respectively to the upper end (as shown in Fig. 1), to the middle part and to the end. bottom of the blank sheet 1. The three central buffers 2, 3 and 4 are aligned in a row parallel to the longitudinal axis of the blank sheet 1, while the buffers 2, 3 and 4 of right and left (as indicated in Figure 1) form respective rows arranged symmetrically with respect to the central row. The scrubbing device 25 comprises a scrubbing element or roll 6 consisting of three scrub discs placed side by side and numbered 7, 8 and 9 from the left to the right of FIG. 2, these discs being partially immersed in a container 10 containing the adhesive; and a rotary pressure element consisting of three pressure rollers placed side by side and numbered 12, 13 and 14 from the left to the right of Figure 2, these rollers being placed essentially tangentially above

respective disks 7, 8 and 9.

  The discs 7, 8, 9 and the rollers 12, 13, 14 are supported and rotated, respectively in the clockwise and counterclockwise direction (FIG. 3) by shafts. respective horizontal parallels 15 and 16 rotatably mounted on the frame 17 of the scrubbing machine 5 and connected, not shown, to a motor (not shown) of the packaging machine (not shown)

  on which the device fits 5.

  The scrub discs 7, 8, 9 and the 10 pressure rollers 12, 13, 14 together define a passage path for the blank sheets 1 which are fed to the scrubbing device 5 one after the other and in the transverse direction by relative to their longest axis, by unrepresented feed means. The passageway is also defined at the bottom by a horizontal cover 18 pierced with openings 19 at the points of tangency between the discs 7, 8, 9 and the

rollers 12, 13, 14.

  The peripheral surface or skirt of each scrub disk 7, 8, 9 has projections or sectors 20 arranged in accordance with the portions of the sheets

  blank 1 to be covered by the rubber pads 2, 3, 4.

  In accordance with the above arrangement of the gum pads 2, 3, 4 on the blank sheets 1, the projections 20, although of different shapes and sizes, are

  equally spaced on the three discs 7, 8, 9.

  As indicated more particularly in FIG. 3, on each of the discs 7, 8, 9, each projection 20 is connected to the following (referring to the direction of rotation of the scrubbing roll 6) by a

  curved surface, so that the outer surface or profile of each scrubbing disc 7, 8, 9 is substantially corrugated and has no sharp edges.

  The periphery and sides of the scrubbing discs 7, 8, 9 are longitudinally, substantially at the axis of the shaft 15, by a cutting edge scraper element 21 forming part of a scraper device identified in FIG. together by reference 22 and intended to remove the excess adhesive from the periphery and sides 5 of the rotating discs 7, 8, 9, leaving only a quantity of adhesive data inside the grooves 23 formed on the peripheral surface of each

projection 20 (Figures 2 and 3).

  Thanks to two radial brackets 24, the scraper element 21 is mounted on the shaft 25 parallel to the shaft 15, and rotatably supported on the frame 17 of the scrubbing device 5. One end of the shaft 25 ( left end in Figure 2) is rigidly connected to one end of a connecting rod 26, the free end supports an intermediate roller 27 maintained by elastic means not shown, against an actuating device consisting of an element of Cam 28 fits on one end of the shaft 25. Although it has no grooves 23, the cam member 28 fits exactly to the contours of the scrub disks 7, 8, 9, and rule relative to the shaft 25 so that the scraper element 21 and the roller 27 are constantly in contact

  with the corresponding parts of the scrubbing discs 7, 8, 9 and with the cam member 28 having substantially the same profile.

  In practical use, the blank sheets 1 are fed successively to the scrubbing device 5 and are coated, by the grooves 23 of the sectors 20, with rubber pads 2, 3, 4 arranged as indicated in FIG. when these blank leaves

  pass between the discs 7, 8, 9 and the corresponding pressure rollers 12, 13, 14.

  The excess adhesive removed from the container 10 by the scrubbing discs 7, 8, 9, is constantly withdrawn by the scraper element 21 which, oscillating about the axis of the shaft 25, razes continuously. by its sharp edges, both the peripheral surface of the projections 20 and the skirt of the discs 7, 8, 9. This oscillation of the scraper element 21 is obtained, via the roller 27 and the connecting rod 26, thanks to the cam member 28 which, as indicated above, has substantially the same profile as the outer surface of the discs 7, 8, 9, and can therefore maintain an extremely close constant play between the scraper member 21 and the outer surface with which it can come into substantially contact. This effective contact is made continuous by the fact that, as indicated above, the outer surfaces of the scrubbing discs 7, 8, 9

  have no sharp edges on the connecting portions between successive projections.

  The variant of the scrubbing device 5 shown in FIG. 5 relates to a scrubbing device 29 in which the shaft 15 supports a scrubbing element consisting of two scrubbing discs placed side by side 30 and 31, the projections 20 are not aligned parallel to the axis of the shaft 15. A configuration of this type is necessary for example when the distance between the pads 2 is different from that

between buffers 3 or 4.

  Each of the discs 30 and 31 is associated with a corresponding scraper element 32, 33, which is supported, as in the scrubbing device 5, by a corresponding bracket 34, fitting to a corresponding shaft 36, 37 rotatably mounted on the frame 17. The shafts 36 and 37 are parallel to the shaft 15 and are provided at their end with a corresponding connecting rod 38, 38 whose free end supports a corresponding roller 40, 41 held by unrepresented elastic means against a corresponding actuating device constituted by a cam member 42, 43 mounted on the shaft 15. Each of the cam members 42, 43 is formed to fit perfectly to the profile of the corresponding scrub disk 30, 31, so as to thereby permanently maintain the corresponding scraper element 32, 33 in the vicinity of the outer surface of the respective scrubbing disc 30, 31. The scrubbing devices 5 and 29 according to the invention therefore allow e remove all the drawbacks related to the state of the art present in the cases where the grooves 23 extend over the entire width of the projections 20. In fact, as the scrub discs 7, 8, 9, 30 and 31 come into contact with the blank sheets 1 only by projections 20 provided with grooves 23, there is absolutely no risk that an adhesive film is applied outside of these given parts to cover pads 2, 3, 4. If, however, the grooves 23 extend only over a portion of the width of one or more of the projections 20, as for example in the case of a central gum pad 4, a film of adhesive covering only a very small surface of only the blank sheet 1, would be applied by the projections portions 20 not including

grooves 23.

  In addition, because of the cleaning action carried out continuously by the scraper elements 21, 32 and 33 on the entire outer surface of the discs 7, 8, 9, 30 and 31, there is no possibility that

  the adhesive accumulates on the surfaces connecting the sectors 20 to the skirts of the discs 7, 8, 9, 30 and 31.

  It will be apparent to those skilled in the art that many modifications can be made to the scrubbers 5 and 29 described and illustrated herein without departing from the scope of the invention. For example, grooves 23 formed on the projections 20 may be dispensed with, in which case the adhesive must be applied directly to the blank sheets 1 by the peripheral surfaces of the projections 20 whose excess adhesive is to be removed as described.

  above, by scraping elements 21 or 32 and 33.

  In addition, as an alternative to the cam elements 28, 42 and 43 above, the displacement of the scraper elements 21, 32 and 33 with respect to the scrub disks-7, 8, 9, 30 and 31, to maintain a game extremely close constant between scrapers and discs, can be achieved by using linear actuators of any type designed to operate in a manner

  the scraper elements 21, 32 and 33 as described above.

he

Claims (4)

R E V E N D I C A T I 0 NS   1) A gumming or gluing device for applying an adhesive to sheets of packaging material such as, in particular, blank sheets of cardboard (1) successively fed to a packaging machine; the device comprising a rotating gumming or gluing member (6 or 30, 31) adapted to extract the adhesive from a container (10) and transfer it onto the blank sheets (1) in the form of buffers (2). , 3, 4) occupying given positions on said blank sheet, the scrubbing element (6 or 30, 31) having, on its peripheral surface, projections (20) for applying the buffers (2, 3, 4) on the virgin leaves (1); and comprising at least one scraper member (21 or 32, 33) located upstream of the point where the adhesive is applied to the blank sheets (1), and adapted to remove excess adhesive on the outer surface of the scrubbing element (6 or 30, 31); device characterized in that it comprises operating means (28, 42, 43) for controlling the displacement of the scraper element (21 or 32, 33) relative to the scrubbing element (6 or 30, 31).   2) Device according to claim 1, characterized in that the scrub member (6) comprises a number of scrub discs (7, 8, 9) supported and driven by a common shaft (15); a scraper element (21) being associated with all the scrubbing discs (7, 8, 9) and being connected to and actuated by a single cam member (28) forming part of the operating means. 3) Device according to claim 1, characterized in that the scrubbing element comprises a number of scrub discs (30, 31) supported and driven by a common shaft (15); a scraper member (32,33) being associated with each of the scrubbing discs (30,31) and being connected to and actuated by a corresponding camming member (42,43) part of the maneuvering means.   4) Device according to any one of claims 2 and 3, characterized in that the scraper member 5 (21 or 32, 33) is moved by the respective cam member (28 or 42, 43) according to the profile of the disc   respective scrubbers (7, 8, 9 or 30, 31).    ) Device according to any one of claims 2 and 3, characterized in that the   cam means (28 or 42, 43) are mounted on a shaft (12) supporting and driving the scrubbing element (6 or 33, 31).   6) Device according to any one of claims 1 to 5, characterized in that, on   each of the scrubbing discs (7, 8, 9, 30, 31), each projection (20) is connected to the next projection   by a surface without sharp edges.