Abstract:
A container-forming device comprises a container conveyor ( 21 ) having a plurality of holders ( 34 ) which each include a bottom plate ( 51 ) and side plates ( 52 ) projecting upwardly from the bottom plate for receiving the container body M 1  and intermittently drivable so as to halt the holders ( 34 ) at an ear bonding station (S 3 ) in succession, and upper ear pressing member ( 61 ) disposed above the ear bonding station (S 3 ) and being moveable upward or downward for pressing upper ears (U 1 ) against an upper wall of a container body (M 1 ), and a pair of lower ear pressing members ( 62 ) arranged at opposite sides of the ear bonding station (S 3 ) and being openable or closable for pressing lower ears (L 1 ) against respective side walls of the container body (M 1 ). Lock members ( 91 ) are provided for locking the side plates ( 52 ) of adjacent holders ( 34 ) to prevent the upper ends of the side plates from moving away from each other when the upper ear pressing member ( 61 ) and the lower ear pressing members ( 62 ) press the ears (U 1 ), (L 1 ) against the container body (M 1 ).

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to packaging machines, and more particularly to a container forming device for use in packaging machines for making a web of packaging material into a tube, filling contents into the tube, transporting the tube a distance at a time which distance corresponds to the length of one container, sealing and cutting the tube transversely thereof to form a pillowlike uncompleted container, and eventually forming the uncompleted container into a rectangular parallelepipedal completed container, the container forming device being adapted to bond ears of the uncompleted container to required portions of the container body under pressure to eventually obtain the rectangular parallelepipedal completed container. 
     As disclosed, for example, in JP-A No. 10-29608 (1998), such forming devices are already known which comprise a container conveyor having a plurality of holders and intermittently drivable so as to halt the holders at an ear bonding station in succession, an upper ear pressing member disposed above the ear bonding station so as to be movable upward or downward for pressing upper ears against an upper wall of a container body, and a pair of lower ear pressing members arranged at opposite sides of the ear bonding station so as to be openable or closable for pressing lower ears against respective side walls of the container body, each of the holders comprising a bottom plate extending in parallel to a container transport path, and a side plate projecting upward from the bottom plate and extending orthogonal to the container transport path. The bottom plates of each pair of adjacent holders are adapted to place the container body thereon, with the side plates of the adjacent holders holding the container body therebetween. A pressure receiving member to be pressed on by the holder lower surfaces is disposed upwardly or downwardly movably so as not to permit upper ends of the side plates of the adjacent holders to move away from each other when the upper ear pressing member and the lower ear pressing members press the ears against the container body. 
     The conventional device described requires drive means for operating the pressure receiving member. This renders the device correspondingly more complex in construction and more costly to manufacture. 
     Further if used for larger containers, especially if the side plate has an increased height, the pressure receiving member is unable to receive the pressure of the upper ear pressing member and the lower ear pressing members to permit the holders to flex. It is then impossible to apply an appropriate pressure to the container, and the ears will not always be bonded to the container body properly. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a container forming device wherein containers can be subjected to an appropriate pressure and which is free of the likelihood of permitting faulty bonding of the ears. 
     The present invention provides a container forming device comprising a container conveyor having a plurality of holders and intermittently drivable so as to halt the holders at an ear bonding station in succession, an upper ear pressing member disposed above the ear bonding station so as to be movable upward or downward for pressing upper ears against an upper wall of a container body, and a pair of lower ear pressing members arranged at opposite sides of the ear bonding station so as to be openable or closable for pressing lower ears against respective side walls of the container body, each of the holders comprising a bottom plate extending in parallel to a container transport path, and a side plate projecting upward from the bottom plate and extending orthogonal to the container transport path, the bottom plates of each pair of adjacent holders being adapted to place the container body thereon, with the side plates of the adjacent holders holding the container body therebetween. The container forming device is characterized in that the device comprises lock means for locking the side plates of the adjacent holders so as not to permit upper ends of the side plates to move away from each other when the upper ear pressing member and the lower ear pressing members press the ears against the container body. 
     With the container forming device of the invention, the pair of adjacent holders are locked directly by lock means to prevent the upper ends of the side plates of the adjacent holders from moving away from each other. This ensures the application of proper pressure to the container to eliminate faulty bonding of the ears. 
     The lock means has lock members movable upward and downward with the upper ear pressing member and engageable with the respective side plate upper ends of the adjacent holders from an upstream side of the container transport path and a downstream side thereof at the lower limit position of the downward movement thereof. The side plates of the adjacent holders can then be locked easily and reliably by the lock members to prevent the upper ends of the side plates from moving away from each other. 
     If each of the lock members has a vertical roller at a side plate engaging portion thereof, the lock members are smoothly engageable with the respective side plates without giving any impact. 
     The lower ear pressing members are attached respectively to lower ends of a pair of levers extending vertically, and a pair of connecting rods are connected, each at one end thereof, to the upper ends of the respective levers and have the other ends connected to a lift tube, the lock members being attached to the lift tube, the lift tube being movable upward and downward by drive means. This construction eliminates the need for a specific mechanism for moving the lock members upward or downward, rendering the lock members operable for locking by a simple mechanism. 
     The upper ear pressing member is attached to a lower end of a vertical lift rod fitted in the lift tube, and the lift rod has a shoulder portion formed approximately at a midportion of the height thereof by providing a small-diameter portion above the portion, the lift tube being provided with a cap at an upper end thereof, a compression coil spring being fitted around the small-diameter portion and provided between the shoulder portion and a top wall of the cap, the lift rod having an upper end extending through the cap top wall to project upward beyond the top wall, a stopper being provided at the upwardly projecting end of the lift rod. The compression of the spring then causes the upper ear pressing member to apply pressure to the upper wall of the container body. This makes it easy to determine the timing for the upper ear pressing member to press the container body upper wall and the timing with which the lower ear pressing members apply pressure to the container body side walls, with the holder side plates engaged by the lock members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary side elevation of a packaging machine including a container feeder of the invention; 
     FIG. 2 is a side elevation of the container feeder; 
     FIG. 3 is a view in longitudinal section taken along the line III—III in FIG. 2; 
     FIG. 4 is a view in cross section taken along the line IV—IV in FIG. 2; 
     FIG. 5 is a perspective view showing an ear bonding device included in the packaging machine and the vicinity of the device; 
     FIG. 6 is a view in cross section of the ear bonding device; 
     FIG. 7 is a view in longitudinal section of the ear bonding device; and 
     FIGS.  8 ( a ) and  8 ( b ) include perspective views of containers. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described next with reference to the drawings. 
     FIG. 1 shows a packaging machine, which comprises a tube forming device  11  for forming a tube T from a web W of paper-base laminate having a thermoplastic resin layer over each of its opposite surfaces by lapping opposite edges of the laminate over each other and sealing the lap, a filling device  12  for filling the tube T with contents, an uncompleted container forming device  13  for forming pillowlike uncompleted containers C 1  from the filled tube T by sealing and cutting the tube T transversely thereof while forwarding the filled tube T a distance at a time which distance corresponds to the length of one container, a completed container forming device  14  for forming the uncompleted container C 1  into a rectangular parallelepipedal completed container C 2 , and a container feeder  15  for feeding uncompleted containers C 1  to the completed container forming device  14 . 
     As shown in detail in FIG.  8 ( a ), the uncompleted container C 1  comprises a container body M 1  having a top portion T 1  and a bottom portion B 1  which are V-shaped in cross section, and a pair of upper ears U 1  and a pair of lower ears L 1  projecting laterally from upper and lower ends although formed in a generally rectangular parallelepipedal shape. 
     As shown in FIG.  8 ( b ), the completed container C 2  comprises a container body M 2  having a complete rectangular parallelepipedal shape and flat top portion T 2  and bottom portion B 2 , a pair of upper ears U 2  lapped over and bonded to the top portion T 2 , and a pair of lower ears L 2  lapped over and bonded to respective side walls of the container body M 2 . 
     With reference to FIG. 1 again, the completed container forming device  14  is provided with a forming conveyor  21  disposed forwardly of the uncompleted container forming device  13  obliquely therebelow and having a path of transport extending forward via a feed station S 0 , folding station S 1 , heating station S 2 , ear bonding station S 3  and discharge station S 4 . 
     The folding station S 1  is provided with a folding device  22  for the uncompleted container C 1  for folding the top portion T 1  and bottom portion B 1  of the uncompleted container C 1  flat and folding the upper and lower ears U 1 , L 1  upward to cause the upper ears U 1  to project upward from the top folded portions and to position the lower ears L 1  close to the respective side walls of the container body M 1 . The heating station S 2  is provided with a heater  23  for heating the portions of the container body M 1  and the ears U 1 , L 1  to be bonded under pressure, the ear bonding station S 3  is provided with an ear bonding device  24  for bonding under pressure the upper ears U 1  to the top portion T 1  in an overlapping manner and pressure-bonding the lower ears L 1  to the side walls of the container body M 1  in an overlapping manner, and the discharge station S 4  is provided with a discharge device  25  for discharging the completed container C 2  from the conveyor  21 . 
     Folding guides  26  extend from the folding station S 1  to the ear bonding station S 3  via the heating station S 2 . While the container C 1  is being transported from the folding station S 1  to the ear bonding station S 3 , the upwardly projecting upper ears U 1  are progressively folded downward to lap over the container body top portion T 1  by the folding guides  26 . Although not shown, similar folding guides are provided also for the lower ears L 1 . 
     The forming conveyor  21  comprises a front drive sprocket  31 , a rear driven sprocket  32 , an endless block chain  33  reeved around these sprockets  31 ,  32 , and a multiplicity of holders  34  connected to the chain  33 , each pair of adjacent holders  34  being in contact with each other. 
     As shown in FIG. 5 in detail, the chain  33  has a multiplicity of transport blocks  41  connected to one another. 
     The transport block  41  has a fitting projection  42  projecting forward from its front portion and a fitting cavity  43  formed in its rear portion and opened rearward. The projection  42  of the transport block  41  in the rear is fitted in the cavity  43  in the preceding block  41 , and a connecting pin  44  extends through the projection  42  and the cavity  43 . The connecting pin  44  has opposite ends projecting laterally from the block and each carrying a support roller  45  thereon. The support rollers  45  are fitted in a pair of guide grooves  47  formed as opposed to each other in a conveyor frame  46 . 
     The holder  34  comprises a flat bottom plate  51  fixed to the upper surface of the transport block  41  and a side plate  52  extending upright from the upper surface of the plate  51 . 
     The bottom plate  51  and the side plate  52  have a width equal to the width of the completed container C 2 . The height of the side plate  52  from the upper surface of the bottom plate  51  is equal to the height of the completed container C 2 . The distance between the side plates  52  of the two adjacent holders  34  is equal to the front-to-rear thickness of the completed container C 2 . 
     FIGS. 5 to  7  show the ear bonding device  24  in detail. 
     The ear bonding device  24  comprises an upper ear pressing member  61  disposed above the ear bonding station S 3  vertically movable for pressing the upper ears U 1  against the upper wall of the container body M 1 , and a pair of lower ear pressing members  62  arranged at opposite sides of the ear bonding station S 3  openably for pressing the lower ears L 1  against the respective side walls of the container body M 1 . 
     A horizontal support plate  63  is provided above the ear bonding station S 3  and has a hole  64  centrally thereof. A vertical guide sleeve  65  is provided upright on the support plate  63  around the upper surface inner periphery thereof defining the hole  64 . At the front and rear sides of the hole  64 , a pair of mound-shaped opposed brackets  66  extend vertically from the lower surface of the support plate  63 . 
     The upper ear pressing member  61  is in the form of a rectangular parallelepipedal block having a thickness in the vertical direction, and is secured to the lower end of a vertical lift rod  71 . An inverted U-shaped escape groove  72  is formed in the lower side of the pressing member  61  for avoiding interference with the folding guide  26 . A vertical lift tube  73  is slidably fitted around the lift rod  71 . The lift tube  73  is slidably fitted in the guide sleeve  65 . 
     The lift rod  71  has a shoulder portion  74  formed at a portion thereof slightly above the midportion of its height by providing a small-diameter portion  75  above this portion. The small-diameter portion  75  has an upper end projecting upward beyond the lift tube  73 . The projecting end is provided with a stopper  76 . The lift tube  73  has an upper end projecting upward beyond the guide sleeve  65  and provided with a cap  77 . Pivotal arms  79  movable upward or downward are connected, each at one end thereof, to the cap  77  by a pair of connecting rods  78  (FIG.  7 ). The small-diameter portion  75  extends through the top wall of the cap  77 . A clearance C is provided between the stopper  76  and the cap  77  for permitting free movement of the lift rod  71  and the lift tube  73  relative to each other. The lift tube  73  is provided close to its lower end with a pair of ears  81  projecting leftward and rightward in opposite directions. 
     The two lower ear pressing members  62  are in the form of rectangular plates extending vertically and opposed to each other leftward and rightward, and are secured to the lower ends of a pair of left and right levers  82  extending vertically. The levers  82  are attached by horizontal support rods  83  to the lower ends of the pair of brackets  66  pivotally leftwardly or rightwardly movably. Attached to the upper ends of the levers  82  are a pair of left and right connecting links  84 . The links  84  have other ends connected to the respective ears  81 . 
     A large outer compression coil spring  86  fitted around the guide sleeve  65  is provided between a spring retainer  85  on the outer surface of the guide sleeve  65  and a flange at the lower end of the cap  77 . A small inner compression coil spring  87  fitted around the small-diameter portion  75  is provided between the shoulder portion  74  and the top wall of the cap  77 . 
     With reference to FIG. 7, a pair of front and rear lock members  91  projecting forward and rearward away from each other in directions orthogonal to the ears  81  and extending forwardly and rearwardly downward obliquely are secured to the lift tube  73  close to its lower end. Each of the lock members  91  has at its lower end a bifurcated portion  92  carrying a vertical roller  93 . 
     On the other hand, a vertical engaging pin  94  is provided upright on the lengthwise midportion of top of the holder  34 . 
     Immediately before the uncompleted container C 1  is brought to the ear bonding station S 3 , the portions to be bonded of the container body M 1  and upper and lower ears U 1 , L 1  are heated by the heater  23 . 
     When the container C 1  is transported to the ear bonding station S 3 , the pivotal arms  79  are lowered by unillustrated means, whereupon the lift tube  73  is lowered along with the lift rod  71 . The upper ear pressing member  61  descending with the lift rod  71  compresses the inner compression spring  87 , thereby pressing the upper ears U 1  against the top wall of the container C 1  to bond the upper ear U 1  to the container upper wall under pressure. When the pressure increases to a predetermined value, the lift rod  71  does not descend further but the lift tube  73  only descends thereafter. Upon the descent of the lift tube  73 , the connecting links  84  move the upper ends of the levers  82  away from each other to move the two lower ear pressing members  62  toward each other. Consequently, the lower ears L 1  are bonded to the respective side walls of the container body M 1  by the pressing members  62 . 
     On the other hand, when the lift tube  73  is lowered to a position a short distance above its lower limit position, the lock members  91  cause the rollers  93  to hold adjacent engaging pins  94  from front and rear sides, whereby the side plates  52  of the adjacent holders  34  are restrained from acting to move the upper ends thereof away from each other. 
     If the pressure of the upper ear pressing member  61  and the lower ear pressing members  62  is exerted on the container body M 1  without restraining the adjacent holders  34 , the adjacent transport blocks  41  flex at an obtuse angle with each other by an amount corresponding to the play of components of the chain  33 , e.g., the clearance in the guide groove  47  around the support roller  45 . This results in the likelihood that the holders  34  will be so flexed as to move the upper ends of the side plates  52  away from each other. Proper pressure then fails to act on the required portions of the container C 1  to entail the likelihood of a faulty seal occurring. However, if the holders  34  are so locked by the rock members  91  as described above, this likelihood is avoidable. 
     FIGS. 2 to  4  show the container feeder  15  in detail. 
     The container feeder  15  comprises a slanting supply chute  101  extending from a position below the uncompleted container forming device  13  to the starting end of transport path of the forming conveyor  21 , and an upper supply conveyor  102  and a lower supply conveyor  103  arranged respectively on the upper and lower sides of the supply chute  101 . 
     The supply chute  101  comprises an upper chute portion  111  and a lower chute portion  112 . The upper chute portion  111  is in the form of a trough as generally known well. 
     As shown in detail in FIG. 4, the lower chute portion  112  comprises a slide plate  121  for guiding the container body M 1  as received thereon, and a pair of guide rails  122  extending in parallel to each other for guiding the ears U 1 , L 1  as received thereon. 
     FIG. 2 shows one holder  34  as halted at the feed station S 0  at the starting end of transport path of the forming conveyor  21 . The holder  34  is in the course of travel around the driven sprocket  32 , and the upper end of the side plate  52  of the holder is joined to the lower end of the slide plate  121  of the lower chute portion  112 . 
     The upper supply conveyor  102  comprises a pair of left and right upper driven sprockets  131  arranged above the lengthwise midportion of the upper chute portion  111 , a pair of left and right upper drive sprockets  132  arranged above a lengthwise intermediate portion of the lower chute portion  112 , a pair of left and right upper endless chains  133  each reeved around the sprockets  131 ,  132  at the same left or right side, and a plurality of upper receiving members  134  attached to the chains  133  at a predetermined spacing. 
     The upper supply conveyor  102  is so disposed that its chains  133  are driven to move counterclockwise in FIG.  2  and to cause the upper receiving members  134  traveling along the lower path of movement of the chains to advance into the path of transport of the chute. 
     Two upper receiving members  134  attached respectively to the left and right chains  133  in the same phase are paired, and the pair of upper receiving members  134  is spaced apart by a distance smaller than the width of the container body M 1 . Accordingly, the container C 1  falling along the chute  101  has the lower end of its bottom portion B 1  received by the pair of upper receiving members  134 . 
     The lower supply conveyor  103  comprises a pair of left and right lower driven sprockets  141  arranged slightly below the upper end of the lower chute portion  112 , lower drive sprockets  142  arranged below the lower end of the lower chute portion  112  at opposite sides of the path of movement of the conveyor holder side plate  52 , a pair of left and right lower endless chains  143  each reeved around the sprockets  141 ,  142  at the same left or right side, and a plurality of lower receiving members  144  attached to the chains  143  at a predetermined spacing. 
     The lower supply conveyor  103  is so disposed that its chains  143  are driven to move clockwise in FIG. 2 in opposite direction to the chains of the upper supply conveyor  102  and to cause the lower receiving members  144  traveling along the upper path of movement of the chains to advance into the path of transport of the chute. 
     Like the upper receiving members  134 , two lower receiving members  144  attached respectively to the left and right chains  143  in the same phase are paired, but the pair of lower receiving members  144  are spaced apart by a distance larger than the width of the container body M 1  but smaller than the distance between the outer ends of the ears U 1 , L 1 . Accordingly, the container C 1  falling along the chute  101  has the lower ends of its upper ears received by the pair of lower receiving members  144 . 
     The two supply conveyors  102 ,  103  are so driven that the upper receiving members  134  move at a higher speed than the lower receiving members  144 . 
     The uncompleted container C 1  is discharged from the uncompleted container forming device  13  by falling. The discharged uncompleted container C 1  is received by the upper chute portion  111  and received by a pair of upper receiving members  134  while falling along the upper chute portion  111  under gravity. The container C 1  is thereafter transported as received by the upper receiving members  134 . Soon after the upper receiving members  134  receiving the uncompleted container C 1  have moved past the location of the lower driven sprockets  141 , a pair of lower receiving members  144  advance to below the upper ears U 1  of the container. Since the upper receiving members  134  move faster than the lower receiving members  144 , the lower receiving members  144  come into contact with the upper ears U 1  of the container received by the upper receiving members  134 , and the upper receiving members  134  leave the container, whereby the upper receiving members  134  are replaced by the lower receiving members  144  for receiving the container C 1 . The uncompleted container C 1  is therafter transported as received by the lower receiving members  144  along the lower chute portion  112 . Upon the lower receiving members  144  reaching the location of the lower drive sprockets  142 , the bottom portion of the container C 1  as received by the lower receiving members  144  is seated on the bottom plate  51  of the holder  34  waiting at the location. In this way, the uncompleted container C 1  is completely delivered from the supply chute  101  to the forming conveyor  21 .