TAPING UNIT FOR CARTON TAPING MACHINE

Abstract: A taping unit for carton taping machine is described. The taping unit comprises a supporting frame (3), means for the feeding (6, 8, 12, 13, 50) of adhesive tape (7), an inlet applicator roller (14) and an outlet applicator roller (23) that are movable from an extracted or rest position, in which thy extend from the volume of said supporting frame (3) so as to be inserted in the feeding path of a carbon box (2), to a retracted or working position, in which they are completely comprised within the volume of the frame (3) in order to allow the feeding of the same box, and shearing means (36) for the separation of a desired portion of adhesive tape to be applied to the box being fed, characterised in that said inlet applicator roller (14) is supported by a movable support (15) that is connected to the frame (3) of the taping unit through an articulated parallelogram mechanism (19, 20) that as a consequence of the engagement of the front of the box being fed with said inlet roller (14) determines a substantially horizontal movement of the same roller (14) accompanied by its simultaneous substantially vertical movement with increasing strain up to said retracted position.

Description: "Taping unit for carton taping machine". DESCRIPTION The present invention concerns a taping unit for carton taping machine. The term "taping machine" is herein utilised in order to identify a machine that is capable to automatically stick portions of adhesive tape on the top and bottom walls (and partially on the front and back vertical ones) of parallelepiped carton boxes that are fed along a certain working path. In such machines the mechanisms predisposed for the distribution of tape and to its sticking on the top and bottom walls of the boxes are called taping units, respectively top and bottom taping units. Known taping units are described in EP-A-0179520 and they essentially comprise a supporting frame destined to be inserted into an appropriate space of the taping machine, means for feeding adhesive tape that is unwound from a continuous reel, an inlet applicator roller for the application of the tape on a short vertical extension of the front wall of the box and along the entire top or bottom wall of the box (depending on whether it is the top or bottom taping unit), an outlet applicator roller for the application of the tape on a short vertical extension of the back wall of the box and a shearing blade for the separation of the portion of tape being applied on the box from said continuous reel. In such taping units the two inlet and outlet applicator rollers move from an extracted or rest position, in which they project from the volume of the frame of the taping unit in such a way as to be inserted in the feeding path of the box, to a retracted or working position, in which they are completely comprised within the volume of the frame in order to allow the feed of the same box. The movement of the inlet applicator roller from the extracted to the retracted position is determined by the engagement of the front wall of the box with the same roller, that it is forced by the aforesaid front wall to move progressively along a return path that allows it at the same time to stick the adhesive tape to the front wall of the box. Once it has retracted, and while the box continues to be fed, the same inlet roller continues the application of the tape along the top or bottom wall of the box. The analogous movement of the outlet applicator roller can in turn be controlled in autonomous way its engagement with the box being fed or can be a direct and obligatory consequence of the retracting movement of the inlet roller. The subsequent recovery movement of the two applicator rollers back to the extracted position is determined by the disengagement of the box from the same rollers in combination with the thrust of appropriate elastic means. During such recovery movement the outlet roller makes the tape adhere to the back wall of the box. In the meantime the shearing blade has carried out the cutting of the portion of tape that is being applied. Particularly interesting is the retracting movement of the inlet applicator roller, that must take place in such a way as to assure the correct sticking of the tape to the front wall of the box with appropriate overcoming of the critical point consisting in the conjunction edge between the aforesaid front wall and the adjacent top or bottom wall, where there are also the flaps of the folded side walls of the box and where it is possible to cause the overturn of the aforesaid ends. At the same time the retracting movement of the inlet roller must be such as not to damage the box, in a particular way in coincidence of the aforesaid edge. In other words the movement must be carried out in such a way as to sufficiently force the tape against the box but also so as to prevent any strains greater that the ones bearable by the same box. A known system for the retraction of the inlet roller provides that the same roller is supported in a freely revolving way by an arm that is hinged on a fixed axis comprised within the volume of the taping unit and near the end for the entrance of the latter, in such a way that the roller follows a path according to an arc of circle with its center on the aforesaid axis. As an alternative, as taught by EP-A-0179520, the inlet applicator roller can be mounted onto an arm or pair of supporting arms that are slidable along arched oblique guides, which are shaped so as to still allow a movement of the roller substantially according to an arc of a circle. In such case the center of the circle arc can be either inside or outside the frame of the taping unit (EP-A-0369501). In view of this state of the art, scope of the present invention is to provide a taping unit for carton taping machine, that has a different and more appropriated system for the retraction of the inlet applicator roller. According to the invention such scope is attained with a taping unit comprising a supporting frame, means for feeding an adhesive tape, an inlet applicator roller and an outlet applicator roller that are movable from ah extracted or rest position, in which they project from the volume of said supporting frame so as to be inserted in the feeding path of a carton box, to a retracted or working position, in which they are completely comprised within the volume of the frame in order to allow the feeding of the same box, and shearing means for the separation of a desired portion of tape to be applied to the box being fed, characterized in that said inlet applicator roller is supported by a movable support that is connected with the taping unit frame through an articulated parallelogram mechanism that as a consequence of the engagement of the front of the box being fed with said inlet roller determines a substantially horizontal movement of the same roller accompanied by its contemporary substantially vertical movement with increasing strain up to said retracted position. In this way the supporting body of the inlet roller remains parallel to itself and the inlet roller moves along a composite path that has a horizontal component that is initially larger and getting smaller and smaller until annulling itself and a vertical component that is initially null and then gets larger and larger. The inlet roller is thus always maintained very adhering to the front wall of the box, at the same time sliding vertically along it in order to make the adhesive tape stick onto the aforesaid wall. When the roller gets in proximity of the end of the front wall, the horizontal component of the movement of the roller is practically null and the roller moves only vertically, so that a final hardening of the stroke of the roller takes place that in addition is useful to allow a better adhesion of the tape onto the edge between the front wall and the top or bottom wall of the box. The characteristics of the present invention will become more evident from the following detailed description of an embodiment thereof that is described for a non limiting purpose in the enclosed drawings, in which: Figure 1 shows a taping unit according to the invention, in longitudinal section, in rest condition; Figure 2 shows said taping unit in top plan; Figure 3 shows the taping unit in Figure 1 during the stage of application of the tape onto the front wall of a box; Figure 4 shows the taping unit in Figure 1 during the stage of application of the tape onto the top of the box; Figure 5 shows the taping unit in Figure 1 during the stage of shearing of the tape; Figure 6 shows the taping unit in Figure 1 during the stage of application of the tape onto the back wall of the box. The taping unit shown in the drawings, where it is indicated as a whole by the reference number 1, is suitable for the application of adhesive tape along the top and part of the front wall and the back wall of a parallelepiped carton box, schematically represented and indicated by the reference number 2, that is fed in the sense indicated by the arrows A in Figures 3-6. The same taping unit once turned upside-down will however be utilisable for the application of the adhesive tape along the bottom and part of the front wall and the back wall of the same or similar box. The aforesaid taping unit comprises a supporting frame 3 that is made in a known way by a pair of vertical parallel walls 4 that are stiffly coupled to each other. From the frame 3 an arm 5 extends upwards that is destined to the support of a reel 6 of adhesive tape 7, with which a drawing roller 8 is kept in contact that is placed on the upper end of an arm 9 hinged in 10 on the frame 3 and elastically biased by a spring 11. The frame 3 supports two idle rollers 12 and 13 for the feeding of adhesive tape 7 drawn from the roller 8 and the taping and shearing devices with relative driving mechanisms. The roller 13 is unidirectional so as to reduce the length of free tape between the drawing roller 8 and the inlet applicator roller 14. This allows a better operation also with tapes having reduced thickness. A first taping device is made up of an inlet applicator roller 14, that is supported in a revolvingly free way by a movable support 15 that is made up of a pair of parallel shoulders 16 that are stiffly bound to each other. Each one of the two shoulders 16 is connected by means of hinges 17 and 18 with one end of two equal levers 19 and 20, that are in turn hinged in 21 and 22 on a respective side wall 4 of the fixed frame 3. The levers 19 and 20 and the shoulders 16 thus form an articulated parallelogram that obliges the support 15 to move in parallel with itself when, as we will see better hereinafter, a box 2 being fed on a bearing plane (not shown) along the sense of the arrow A engages the inlet roller 14 and it pushes it toward the left (looking at Figure 1). A second taping device is made up of an outlet applicator roller 23, that is supported in a freely revolving way by another movable support 24 that is made of a pair of parallel levers 25 stiffly bound to each other. The two levers 25 are hinged on a hinge 26 that is fixed to the frame 3 and they are kept in the rest position of Figure 1 (defined by the abutment engagement of the levers 19 with a shock absorber 49) by a helicoidal spring 28, that has one end fastened to a pin 29 fastened to the levers 25 and the other end fastened to a corresponding end of a chain 30 conveyed in 31 towards an adjustment device 32, that through the chain 30 adjusts the tension of the spring 28. The levers 25 are connected with the support 15 of the inlet roller 14 by a pair of arms 33 with ends hinged in 34 and 35. In intermediate position between the movable support 15 of the inlet roller 14 and the movable support 24 of the outlet roller 23 a shearing unit 36 is arranged that comprises a shearing blade 37 supported by a first revolving support 38 hinged in 39 on a second revolving support 40 hinged in 41 on the frame 3. A first spring 42 wound around the pin 39 and reacting between the first revolving support 38 and a pin 43 held by the second revolving support 40 biases the blade 37 toward a position of rest defined by the abutment engagement of the first revolving support 38 with the pin 43, while a second spring (or better a pair of springs) 44 wound on a fixed hinge 45 and reacting between an additional fixed hinge 46 and the pin 43 that biases the second movable support 40, and therefore the entire shearing blade 36, toward a position of rest defined by the abutment engagement of the second movable support 40 with a fixed pin 47. A protection case 48 fastened to the arms 33 prevents, when at rest, the accidental access to the shearing blade 37. When at rest, the spring 28 keeps the outlet applicator roller 23 in the extracted position of Figure 1, that is external to the frame 3 and in the feeding path of the box 2. Correspondingly, the two connection arms 33 keep the inlet applicator roller 14 in the extracted position of Figure 1, in which the two levers 19 are in contact with the shock absorber 49. Finally the spring 44 keeps the shearing blade 36 in the extracted position of Figure 1 with the case 48, as already said, places as a protection of the shearing blade 37. Let's suppose that a box 2 having a front vertical wall 51, a top front edge 52, a top wall 53 (actually made up of end flaps and side walls refolded into a closing position), a upper back edge 54 and a back vertical wall 55 is fed in the sense indicated by arrow A onto a bearing plane underneath (not shown) from which the base of the frame 3 of taping unit lis distant in measure equal to the height of the box. Let's also suppose that the adhesive tape 7 has previously been unwound from the reel 6 in front of the inlet roller 14 passing through the rollers 8, 12, 13 and 50, the latter revolvingly held by the movable support 15. The front wall 51 of the box 2 initially meets the inlet applicator roller 14, receiving from same the initial end of the tape 7, whose adhesive side, turned toward the outside, consequently adheres to the same front wall. By continuing the feeding of the box (Figure 3), the thrust exerted by its front wall on the inlet roller 14 determines the progressive sliding of the movable support 15, that for effect of the articulated parallelogram made up of the levers 19 and 20 is maintained parallel to itself while the inlet roller 14 makes a composite movement with progressively decreasing horizontal component and progressively increasing vertical component that causes the progressive complete retraction in the volume of the fixed frame 3 of the taping unit and at the same time it allows it to apply subsequent portions of adhesive tape 7 to the front wall of the box and up to the top edge 52. The last part of the retracting movement of the inlet roller 14 has a very small horizontal component and a very large vertical component with increasing strain, therefore the same movement undergoes a hardening, that in addition is useful so as to assure the perfect adhesion of the tape 7 to the top edge 52. In this stage, owing to the connection assured by the arms 33, the outlet applicator roller 23 too is recalled inside the volume of the frame 3. Once the edge 52 has been passed and with the inlet roller 14 and the outlet roller 23 completely retracted within the volume of the frame 3, the top wall 53 of the box receives in turn the adhesive tape 7 (Figure 4), that continues to unwind from the reel 6 and to be distributed by the inlet roller 14. The shearing unit 36 is in turn forced by the same box to retract within the volume of the frame 3 for effect of the engagement of the upper front edge 52 with the movable support 40. The shearing blade 37 is not any more protected by the protection case 48. When the upper back edge 54 abandons the movable support 40, the latter is forced to snap again into the extracted position by the spring 44 and the shearing blade 37 consequently engages and cuts the adhesive tape 7, by separating the portion of tape aheady unwound from the one still attached to the reel 6 (Figure 5). When the outlet roller 23 passes the upper back edge 54 too, the outlet roller 23 starts extending from the volume of the frame 3 and to descend along the back wall 55 of the box, thus making the terminal section of the adhesive tape that was already applied to the front and top wall of the box adhere to the same (Figure 6). Finally the spring 28 brings both applicator rollers 14 and 23 back to the rest position, thus predisposing the taping unit 1 for a subsequent taping operation.

Claims: CLAIMS 1. Taping unit for carton taping machine, comprising a supporting frame (3), means for the feeding (6, 8, 12, 13, 50) of adhesive tape (7), an inlet applicator roller (14) and an outlet applicator roller (23) that are movable from an extracted or rest position, in which they extend from the volume of said supporting frame (3) so as to be inserted in the feeding path of a carton box (2), to a retracted or working position, in which they are completely comprised within the volume of the frame (3) in order to allow the feeding of the same box, and shearing means (36) for the separation of a desired portion of adhesive tape to be applied to the box being fed, characterised in that said inlet applicator roller (14) is supported by a movable support (15) that is connected to the frame (3) of the taping unit through an articulated parallelogram mechanism (19, 20) that as a consequence of the engagement of the front of the box being fed with said inlet roller (14) determines a substantially horizontal movement of the same roller (14) accompanied by its simultaneous substantially vertical movement with increasing strain up to said retracted position. 2. Taping unit according to claim 1, characterized in that said outlet applicator roller (23) is in turn provided with a movable support (24) that rotates around a hinge (26) that is fastened to said frame (3). 3. Taping unit according to claim 2, characterized in that said mobile supports (15, 24) of the inlet and outlet applicator rollers (14, 23) are connected with each other by at least one arm (33) hinged to the ends (35, 34). 4. Taping unit according to claim 3, characterized in that it comprises elastic means (28) that are suitable to hold said movable supports (15, 24) in a rest position. 5. Taping unit according to claim 4, characterized in that said elastic means (28) are made up of a spring (28) reacting between the movable support (24) of the outlet roller (23) and an adjustment device (32) held by the frame (3) of the taping unit.

Inventors: MARCHETTI ANTONIO, MARCHETTI, ANTONIO
Applicants: COMARME MARCHETTI F A S P A, MARCHETTI ANTONIO, COMARME MARCHETTI F.A. S.P.A., MARCHETTI, ANTONIO
Application year: 2001
Main classification: B65B51
IPC codes: B65B51