CARTON FLAP FOLDING MECHANISM

Abstract: In a machine for packaging articles in a tubular wrap-­ around carrier formed from a blank having a pair of walls adjoined together along a fold line and having a pair of article retaining and blank reinforcing flaps disposed astride the fold line, and which includes means for advancing a blank and its associated articles along a predetermined path, a mechanism for engaging and folding the pair of flaps and to fold such flaps inwardly of the carrier. The folding mechanism comprises a pivotal folder 'f' adapted to execute a folding movement thereby progressively to enter an aperture in the blank to fold the flaps and to retract therefrom during feed movement of the blank and the pivotal folder together through a folding station of the machine.

Description: This invention relates to a mechanism of the type disclosed in European Patent Application No 0 200 445 and more specifically to the carton blank folding devices including pivotal folders included therein. Such pivotal folders are used to fold bottle retaining and blank reinforcing flaps which define bottle heel receiving apertures, into overlapping relationship with adjacent portions of the carton blank to which they are hinged. Such retaining and reinforcing flaps are incorporated in the carton blank shown in European patent Application No 0 171 229 which is incorporated herein by reference. This flap folding operation is performed while the carton blank is advanced together with the folding devices of the mechanism through the infeed end of a packaging machine. In the known construction, each pivotal folder comprises a pair of blank engaging pivotal fingers arranged to open and close together in response to movement of a spherical cam follower, forming a part of the pivotal folder, along a cam track. In order to perform the flap folding operation, the pivotal fingers are pivoted into one extreme outward position in which the fingers are caused to move apart together to engage and fold the carton flaps of a bottle heel retaining aperture and are thereafter pivoted into a fully retracted position in which the fingers are caused to close together. However, it has been found that there is a tendency for the known pivotal fingers to strike the bottles or other articles to be packaged, resulting in a bottle breakage risk and/or likelihood of an incomplete flap folding operation. The present invention seeks to alleviate this problem and to create an improved folding action by causing the pivotal fingers to move downwardly during their opening movement. To this end, one aspect of the invention provides in a machine for packaging articles in a tubular wrap-around carrier formed from a blank having a pair of walls adjoined together along a fold line and having a pair of article retaining and blank reinforcing flaps disposed astride said fold line and which includes means for advancing a blank and its associated articles along a predetermined path, a mechanism for engaging and folding said pair of flaps and to fold such flaps inwardly of the carrier, said folding mechanism comprising a folder adapted to execute a folding movement thereby progressively to enter an aperture defined at least partially by said pair of flaps, in the blank to fold the flaps and to retract therefrom during feed movement of the blank and said folder together through a folding station of the machine, said folder including a pair of blank engaging fingers and means for cooperation with actuating means to cause opening and closing movement of said fingers, characterised in that said pair of fingers are interconnected for the opening and closing movement together during said folding and retracting movements respectively, and in that said cooperating means is carried by each of said pair of fingers, the cooperating means of one finger controlling said opening movement of the pair of fingers, and the cooperating means of the other finger controlling said closing movement of the pair of fingers. Another aspect of the invention comprises, in a machine for packaging articles in a tubular wrap-around carrier formed from a blank having a pair of walls adjoined together along a fold line and having a pair of article retaining and blank reinforcing flaps disposed astride said fold line and which includes means for advancing a blank and its associated articles along a predetermined path a method of folding said pair of flaps inwardly of the carrier, in which a folding mechanism comprising a folder is adapted to execute a folding movement thereby progressively to enter an aperture defined at least partially by said pair of flaps, in the blank to fold the flaps and to retract therefrom during feed movement of the blank and said folder together through a folding station of the machine, characterised in that said pair of fingers are caused to open and close together during said folding and retracting movements respectively, and in that one of said fingers controls said opening movement of the pair of fingers, and the other of said fingers controls said closing movement of the pair of fingers. An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:- FIGURE 1a is a plan view of a folder of the mechanism in which a pair of pivotal fingers are shown in closed position; FIGURE 1b is a perspective view of the folder as seen remote from the pivotal fingers. FIGURE 1c is a side view of the folder; FIGURE 2a is a plan view of the folder in which the pivotal fingers are shown in open position; FIGURE 2b is a perspective view of the folder showing pivotal fingers; FIGURE 2c is a plan view of the folder as seen with the pivotal fingers open; FIGURE 3 is a plan view of a cam track through which cam followers of the folders move to cause opening and closing movement of the pivotal fingers; FIGURE 4 is a front elevation of the cam track; and FIGURE 5 is a plan view of the mechanism in which the folders are carried by an endless chain. Referring first to Figure 5 of the drawing, the blank folding mechanism 10 comprises a chain and sprocket set comprising spaced sprockets 12 and 14 respectively, about which is entrained endless chain 16. The blank folding mechanism is adapted to be installed adjacent the infeed end of a packaging machine. Two such mechanisms are installed in side-by-side relationship so that a blank and article feed path is provided between the mechanisms. The description hereinafter refers to one such mechanism of the pair. A series of carton blank folders 'f' are secured to the endless chain at spaced locations along its length so that successive bottle retaining and blank reinforcing flaps in a carton blank can be folded as the blank passes through the mechanism. The endless chain 16 is driven in synchronism with the blank feed and thus each folder is moved along the chain paths at the same speed as a carton blank passing through the mechanism. In operation of the mechanism each blank folder is moved by the chain 16 along a working path 'W' parallel to a blank and article feed path 'F' and thereafter along a return path 'R'. As a folder approaches the working path 'W', it moves along a convergent path 16A so that the pivotal fingers of the folder are progressively caused to enter a bottle heel aperture of the carton blank. Referring to Figures 1a-1c and 2a-2c, each folder 'f' comprises a support block 20 including a central raised portion 22 on which the pivotal fingers P1 and P2 are supported. The central raised portion comprises upwardly convergent flats 22 a and 22 b from which extend pivot shafts 24 and 26 respectively such that the angle subtended between the axes of the pivot shafts is 53.13 degrees. It has been found that this angle gives the requisite downward component of travel of the pivotal fingers during their opening movement. The pivotal fingers P1 and P2 are mounted on respective ones of the pivot shafts 24 and 26 by a bored through mid-portion PM1 and PM2. Each of the mid-portions are formed with a bevel gear segment PG1 and PG2 which meshes with the gear segment of the other pivotal finger. Thus, clockwise rotation of pivotal finger P1 causes simultaneous anti-clockwise rotation of pivotal finger P2. The pivotal fingers further include carton blank engaging portions PB1 and PB2 extending in one direction (forwardly) of the mid-portions of the respective pivotal fingers and actuating arms PA1 and PA2 extending in the opposite (rearward) direction of the mid-portions of the respective pivotal fingers. Both actuating arms terminate in spherical cam followers PF1 and PF2. As best seen in Figures 1c and 2c, actuating arm PA1 lies in a plane which is above that occupied by the actuating arm PA2 such that the arms can be caused to move relative to one another without mutual interference as described below. The inclined mounting of the pivotal fingers on the convergent flats 22a and 22b of the support block results in an arrangement in which the blank engaging portions of the fingers extend substantially horizontally from the mounting block when the blank engaging portions are closed, as shown in Figures 1a-1c, and in which the blank engaging portions are inclined downwardly when fully opened to 90 degrees as shown in Figures 2a-2c. The angle subtended between the plane containing each blank engaging portion of a finger and a plane containing the base of the mounting block is substantially 30 degrees when the fingers are fully open. Thus, when the fingers are open, the blank engaging portions move apart and progressively downwardly to their fully opened 90 degrees condition. This opening action has been found to minimise the risk of bottle contact by the blank engaging portions of the fingers and also to improve proper folding of the bottle retaining and blank reinforcing flaps. The 30 degrees angle is chosen to coincide with the plane containing the carton panel against which the flaps are to be folded. Referring now also to Figures 3 and 4, the pivotal fingers are actuated by a cam track 28 formed in a cam block 30 disposed alongside the feed path 'F' and adapted to receive the actuating arms and cam followers of the pivotal fingers as each folder passes through the working path 'W'. The pivotal action is now described in which the pivotal finger P1 of a folder leads movement in the feed direction shown and pivotal finger P2 trails. A series of successive positions of the respective spherical cam followers is shown schematically in the cam track 28. As the actuating arms of a folder enters the cam track, in closed position, the cam follower PF1 strikes inclined cam surfaces 32 in the 'opening section' of the track which causes the actuating arm PA1 to move in opposition to the feed direction and towards the neighbouring actuating arm PA2. This pivotal action causes simultaneous movement of the blank engaging portions of the pivotal fingers away from one another by virtue of the geared connection between the fingers thereby bringing the pivotal fingers into their opened position. The other cam follower PF2 has a clear path of movement through the opening section of the cam track. A straight mid-section of the cam track allows the fingers to be maintained in the open condition. The actuating arms then enter a 'closing section' of the cam track in which the cam follower PF2 strikes inclined cam surface 34 which causes actuating arm PA2 to move in opposition to the feed direction and away from the neighbouring actuating arm PA1. This pivotal action causes simultaneous movement of the blank engaging portions of the pivotal fingers to move towards one another thereby returning the pivotal fingers to their closed position. Of course, immediately prior to the opening section, the convergent chain path 16A of movement of the folders towards the feed path of the carton blank causes the blank engaging portions of each folder progressively to enter a carton bottle heel retaining aperture thereby displacing and folding the carton flaps during movement of the fingers through the opening section of the cam track. The fingers remain engaged in the carton in opened position through the mid section of the cam and are thereafter progressively retracted during movement of the pivotal fingers through the closing section of the cam track by virtue of the divergent chain path 16b.

Claims: In a machine for packaging articles in a tubular wrap-around carrier formed from a blank having a pair of walls adjoined together along a fold line and having a pair of article retaining and blank reinforcing flaps disposed astride said fold line and which includes means for advancing a blank and its associated articles along a predetermined path, a mechanism (10) for engaging and folding said pair of flaps and to fold such flaps inwardly of the carrier, said folding mechanism comprising a folder (f) adapted to execute a folding movement thereby progressively to enter an aperture defined at least partially by said pair of flaps in the blank to fold the flaps and to retract therefrom during feed movement of the blank and said folder together through the machine, said folder including a pair of blank engaging fingers (P1, P2) and means PA1, PA2) for cooperation with actuating means to cause opening and closing movement of said fingers, characterised in that said pair of fingers are interconnected for the opening and closing movement together during said folding and retracting movements respectively, and in that said cooperating means is carried by each of said pair of fingers, the cooperating means of one finger controlling said opening movement of the pair of fingers, and the cooperating means of the other finger controlling said closing movement of the pair of fingers. A mechanism according to claim 1, further characterised in that said cooperating means and said actuating means cause downward pivotal movement of said fingers during said opening movement. A mechanism according to claim 2, further characterised in that said fingers are mounted on upwardly convergent surfaces (22a, 22b) of support means (20) upon which said fingers are pivotal thereby to produce said downward pivotal movement of said fingers during said opening movement. A mechanism according to claim 3, further characterised in that said fingers move apart by an angle of substantially 90 degrees and downwardly through an angle of substantially 30 degrees during said opening movement. A mechanism according to any of the preceding claims, further characterised in that said actuating means comprises a cam track (28) provided at said folding station and in that said cooperating means comprises for each blank engaging finger an actuating arm (PA1, PA2) for engagement with said cam track thereby to execute said folding movement of said folder. A mechanism according to claim 5, further characterised in that the follower arm of one of said fingers is disposed in a different plane to the follower arm of the other of said fingers such that during said opening and closing movement said follower arms are caused to move relative to one another without interference and in that one of said follower arms cooperates with a cam surface of said cam track to control opening movement of the pair of fingers and the other of said follower arms cooperates with another cam surface of said cam track to control closing movement of the pair of fingers. A mechanism according to claim 6, further characterised in that said cam track comprises an opening section having a cam surface (32) inclined to the direction of travel of said follower arms and which is engaged by said one follower arm (PA1) to cause opening movement of said pair of fingers, a closing section having a cam surface (34) inclined to the direction of travel of said follower arms and which is engaged by said other follower arm (PA2) to cause closing movement of said pair of fingers, and a mid-section in which said fingers are maintained in their opened condition. A mechanism according to any of the preceding claims, further characterised in that said interconnecting of said pair of fingers comprises meshed gears (PG1, PG2). A mechanism according to claim 8, further characterised in that each of said pivotal fingers comprises a mid-portion (PM1, PM2) formed with a bevel gear segment (PG1, PG2) which meshes with a like bevel gear segment of the other pivotal finger, a carton blank engaging portion (PB1, PB2) extending in one direction away from the mid portion and an actuating arm extending (PA1, PA2) in a direction opposite to said one direction away from the mid portion, said actuating arm terminating in a cam follower (PF1, PF2). In a machine for packaging articles in a tubular wrap-around carrier formed from a blank having a pair of walls adjoined together along a fold line and having a pair of article retaining and blank reinforcing flaps disposed astride said fold line and which includes means for advancing a blank and its associated articles along a predetermined path, a method of folding said pair of flaps inwardly of the carrier, in which a folding mechanism comprising a folder (f) is adapted to execute a folding movement thereby progressively to enter an aperture defined at least partially by said pair of flaps in the blank to fold the flaps and to retract therefrom during feed movement of the blank and said folder together through the machine, characterised in that said pair of fingers are caused to open and close together during said folding and retracting movements respectively, and in that one of said fingers controls said opening movement of the pair of fingers, and the other of said fingers controls said closing movement of the pair of fingers.

Inventors: LOURET, G., STAHL, A.
Applicants: THE MEAD CORPORATION
Application year: 1988
Main classification: B65B11
IPC codes: B65B11, B31B1