Patent Publication Number: US-2005124478-A1

Title: Side wall flap folding mechanism for carton forming machine

Description:
CROSS REFERENCE TO RELATED APPLICATION  
      This application is a Continuation-in-Part of U.S. patent application Ser. No. 10/343,032 filed Jul. 17, 2003, which is the national stage of International Patent Application Serial No. PCT/AU01/00913 filed Jul. 26, 2001, which claims the priority of Australian Patent Application Serial No. PQ 9060 filed Jul. 27, 2000, all of which are hereby incorporated herein by reference. 
    
    
     FIELD  
      This specification relates to a side wall flap folding mechanism for a carton forming machine.  
     BACKGROUND  
      Carton forming and filling machines are now widely used in the packaging of consumer products such as beverages. Such machines must be capable of automatically erecting and sealing the carton or case ready for filling by means of a separate filling apparatus.  
      Examples of carton or box forming machines may be found in the patent literature, and include Australian Patent No. 640503, and U.S. Pat. No. 5,147,271, in both of which a corrugated cardboard blank is formed around a mandrel where the side and end panels are glued and the partly erected box is ejected from the mandrel as an open-topped box ready for filling.  
      In our International Patent Application PCT/AU00/01215, published Sep. 13, 2001 as Publication No. WO0166423 filed Sep. 9, 2002 as U.S. patent application Ser. No. 10/221,073), the contents of which are incorporated herein by reference, we describe a reinforced container suitable for fluid-filled bags or other contents, formed from corrugated board or similar packaging materials and including side panels having extension portions which are foldable and secured to form double thickness side panels and end flaps which serve to reinforce the side and end panels of the container. It will be appreciated that the blank for forming the improved reinforced container is large and a modified flap folding arrangement is described in which the side flaps are initially folded lengthwise rather than transversely, as is usually the case, followed by folding of the blank around a mandrel to form the carton.  
     SUMMARY  
      It is an object to provide a side flap folding means for a case forming machine in which the blanks are folded in a manner which ensures substantially continuous operation at a relatively high throughput.  
      The present specification discloses a side flap folding mechanism for carton forming machine, comprising a blank feeder operative to move a blank in a predetermined direction, side flap folders for folding side wall flaps at opposite sides of the blank about a predetermined fold line extending transverse to the direction of movement of the blanks to form double thickness side walls, the side wall flaps being folder opposite to the direction of movement of the blanks, the side flap folders including means for confining the folding of the side wall flaps to the predetermined fold line.  
      In one form, the fold confining means includes arms, each arm having an edge which is positioned adjacent the predetermined fold line while the blank feeder is paused to allow initial folding of the flaps through about 90°.  
      The mechanism may also include means, such as centre wheels or a driven hold down belt, to hold the centre of the blank down as the side wall flaps are folded.  
      The flap folders may comprise any known form of flap folding mechanisms, such as rotating folding arms which operate to fold the side flaps longitudinally as the blank is moved by the feeding means. Initial bending of the side flaps through about 90° while the blanks are held at the predetermined fold line may be by way of rotating folding arms, and this folding operation may be followed by the use of compressor rollers or belts to complete the folding of the side flaps through 180°.  
      The side flaps are held in compression by the rollers or belts for a period sufficient to ensure that the glue between the folded flap portions sets.  
      The specification further discloses a method of forming a carton from a blank having elongate side wall flaps, comprising the steps of folding the side wall flaps lengthwise about a transverse fold line, gluing the folded side wall flaps to form double thickness side panels, and completing folding and gluing of the blank to form the carton.  
      In one form the folding step comprises holding the side wall flaps adjacent the transverse fold line, folding the side wall flaps through about 90° along the transverse fold line, completing folding of the side wall flaps through 180°, and compressing the folded side wall flaps to set glue between the folded portions of the side wall flaps.  
      The method may further comprise supporting the side wall flaps at their inner edges and transversely of the flaps during folding of the side wall flaps through 90°, removing the edge support from the side wall flaps, and moving the blank forwardly so that the transverse support further folds the flaps from 90° towards 180°.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In order that the disclosure may be more readily understood, a presently preferred embodiment of the invention will now be described with reference to the accompanying drawings in which:  
       FIGS. 1 and 2  are partly schematic perspective views of a blank side flap folding mechanism in the rest and operative positions respectively;  
       FIG. 3  is a partly schematic perspective view of the folding mechanism of  FIGS. 1 and 2  illustrating the blank feeder and the flap folding and compressing mechanisms; and  
       FIG. 4  is a partly schematic perspective view of the folding mechanism showing the glue applicators. 
    
    
     DESCRIPTION OF EMBODIMENT  
      The present embodiment is designed to perform the first folding operation of the side flaps sf of a carton blank B, as illustrated in FIGS.  1  to  3 . The blank B is a modified version of the blanks described in co-pending U.S. patent application Ser. No. 10/221,073, Holland, to the extent that closure flaps cf extend from the side panels of the blank B rather than from the top, the side flaps sf extending from the side panels on either side of the central portion C of the blank B, the side flaps sf including a predetermined fold line F about which the side flaps sf are folded by the mechanism to be described below to form double thickness sides in the eventually formed carton, as described in the co-pending application referred to above.  
      FIGS.  1  to  3  illustrate an embodiment of a side flap folding mechanism  30  which replaces the mechanism described in parent application Ser. No. 10/343,032 Scholtes, and which enables the long side flaps sf of the blank B to be folded and glued without comprising the integrity of the blank B. Mechanisms for feeding or supplying the blanks to the folding mechanism  30 , and mechanisms for completing the folding of the blank B partly folded by the mechanism  30  are well known to those of skill in the art and are therefore not described herein. Reference may be had to parent U.S. patent application Ser. No. 10/343,032 Sholtes, for a description of one form of a blank feeder and mechanisms for completing folding of the blank B of a complete carton forming machine of which the folding mechanism  30  forms a part.  
      As shown in FIGS.  1  to  3 , blanks B supported by side rails R are fed to the side flap folding mechanism  30  by a blank B feeding mechanism  50 , which includes known re-circulating dogs  51 ,  52 , illustrated schematically in  FIG. 3 , which engage the rear edges of the blanks B as illustrated in  FIG. 3  to move them generally in direction D through the mechanism  30 . Mechanism  50  has at least a paused state in which it is not advancing the blank B, and an operative state in which it is advancing the blank B.  
      The mechanism  30  includes a pair of fold confining arms  31 , and a pair of folding arms  32 , which operate to fold the side flaps st, which have been previously glued by glue applicators  56 ,  FIG. 4 , while the blank B feeding mechanism  50  is paused for a short period in a known manner. It will be noted that the folding arms  32  include a driven arm  36  extending from a driving mechanism  36   a , a cross member  37 , and a side flap edge support element  38 , which provides support for the side flaps st so that the cross members  37  and the support elements  38  lift and rotate the side flaps st, rather than just the cross members  37  lifting and rotating the side flaps st. This ensures that the slide flap is folded along the predetermined fold line F without buckling. The driving mechanism  36   a  includes a cam follower  36   b  attached to the drive shaft  36   c  and engaging a cam slot  36   d , the shaft  36   c  being mounted in bearings  36   e  which allow lateral movement of the shaft  36   c  as it is rotated.  
      The fold confining arms  31  are driven by motors  34  between a substantially vertical or retracted position, as shown in  FIG. 1 , to allow for the positioning of a new blank B by the feeding mechanism  50 , and a substantially horizontal or operative position, as illustrated in  FIG. 2 , in which lower edges  35  of the arms  31  are in contact or close proximity with the blank B in alignment with the predetermined fold line F of the side flaps sf, as illustrated in  FIG. 2 .  
      When the arms  31  are in the operative position and while the blank B is temporarily stationary, the folding arms  32  are rotated by their driving mechanisms  36   a  to a substantially vertical position, as illustrated in  FIG. 2 . During rotation, the arms  32  are moved laterally by about 10 mm by the cam follower  36   b  in the cam slot  36   d  of the drive mechanism  36   a  so that the edge support elements  38  are clear of the edges of each side flap sf. The fold confining arms  31  are moved to their rest or retracted positions during or after rotation of the folding arms  32 . The blank B is then fed forwardly by mechanism  50  to further fold the side flaps sf, to the position shown in  FIG. 3 , by engagement between the side flaps and the support  38  of the fold arms  32  as the blank B moves forward. The arms  32  are then returned to their rest position ( FIG. 2 ) below the level of the blank B, to enable feeding of a new blank B to the folding position. Initially, the support element  38  is beneath a side flap st and, once rotation of the support element  38  has begun, and preferably before the blank B has begun moving forward again, the support element  38  is moved laterally so as not to interfere with or damage the side flap st. Note that, by virtue of the action of the cross member  37  and the support element  38 , the side flap st may be considered to be folded opposite to the direction of movement D of the blank B.  
      During the folding operation, the central portion C of the blank B is held down by a hold down mechanism  33  in which the central portion C of the blank B is trapped under pressure rollers  39  and confining plates  40  carried by the frame of the mechanism.  
      The folding of the side flaps sf is completed by passing the further folded flaps between a known compression belt mechanism  55 , as illustrated in  FIG. 3 . The folded side flaps are held in the belt mechanism  55  for a sufficient time for the glue previously applied to the side flaps sf to set.  
      As illustrated in  FIG. 4 , glue applicators  56  are mounted on the motors  34  adjacent the fold confining arms  32  and are operable in a known manner to apply glue lines g to the side flaps sf as the blanks B are moved to the folding position by the feeding mechanisms  50 .  
      The above described mechanism allows blanks B to be folded in the above described manner at relatively high throughput rates without comprising the integrity of the side flaps, to allow the formation of a completed carton, as described in U.S. Ser. No. 10/343,032, and similar to the carton described in U.S. Ser. No. 10/221,073 Holland, having reinforced side walls and end walls.