Box erector
BACKGROUND OF THE INVENTION 
     The invention relates to a box erector for erecting boxes from a knock-down condition. 
     Heretofore, box erector apparatus have been proposed for setting up folded carton or box planks, closing their bottom flaps, and sealing the bottom flaps so that the box may be loaded. For example, see U.S. Pat. Nos. 4,579,551; 4,348,853; and Re27,631. Pat. No. Re27,631 discloses a box erector which utilizes suction for grasping portions of the knock-down carton during erection, and various actuators for closing the end and side flaps. While apparatus have been previously proposed for automatically erecting boxes, they have not been entirely suitable, particularly, as an adjoining operation to an existing product line whereby boxes can be erected and fed to a feeding system for filling of the boxes with packaged products and the like. In addition, the prior box erectors have been relatively complicated in construction, and have required a large amount of floor space. This has made them particularly unsuitable for utilization in existing floor space as an adjunct to an existing product line for erecting the boxes to be filled at the product line in conjunction with the manufacturing of products. 
     Accordingly, an object of the invention is to provide a box erector having a small footprint which can be utilized without modification with an existing product feeding system. 
     Another object of the invention is to provide a compact box erector which is simple, yet reliable, and can be utilized as an adjunct to an existing product feeding system for boxing of the product. 
     Another object of the invention is to provide a box erector which may be utilized to erect different size boxes without complicated alteration of the erector. 
     Another object of the invention is to provide a box erector which erects boxes taken from an inventory of boxes stacked in a knock-down condition in a simple and reliable manner. 
     SUMMARY OF THE INVENTION 
     The above objectives are accomplished according to the invention by providing an apparatus for erecting a rectangular box from a folded knock-down box which requires a small amount of floor space and may be displayed adjacent a product feed line to package product in the erected boxes in a continuous automatic manner. 
     The apparatus includes an inventory section which includes an inventory of stacked knock-down boxes with a top box in a pick-up position. A transfer section includes transfer means for picking up the top box disposed on top of stacked knock-down boxes and transferring the top box to a box-opening position. The transfer means includes a box opening means for opening the box into an open rectangular box at the box-opening position. A closure section receives the rectangular box at a box closure position, and includes a flap closure assembly for folding a pair of end and side flaps of the box inward for closure. The transfer means transfers the open rectangular box from the box-opening position to closure section only after the box has been opened. A taping section includes a taping unit for securing the end and side flaps in a closed configuration to form a box enclosure. An indexing means raises the stack of knock-down boxes a prescribed distance each time the transfer means picks up one of the top boxes so that a box previously underneath the top box is raised to a predetermined pick-up height and becomes a new top box. A release means is provided for releasing the indexing means so that platform may be returned to a bottom position for reloading of a stack of knock-down boxes. A brake means brakes the descent of the platform when lowered to reload position. 
     Preferably, the transfer means includes a transfer arm, and a transfer drive for rotating the transfer arm through a prescribed angle between the box pick-up, box opening, and the box closure positions. The transfer drive includes first drive for rotating the transfer arm through a first prescribed angle between the box closure and the pick-up positions, and for rotating the transfer arm through a second prescribed angle less than the first prescribed angle, and in an opposite direction. The transfer drive includes a base pivot having a pinion gear affixed to the transfer arm and carried by the base pivot. The first drive includes a rack gear meshing with the pinion, and a first fluid cylinder having a piston rod affixed to the rack gear, and a second fluid cylinder carried by the frame having a piston rod on which the first fluid cylinder is carried. Both fluid cylinders are actuated to move the transfer arm between the closure and pick-up positions. One of the first and second fluid cylinders rotates the transfer arm from the pick-up position to the box-opening position, and the other of the fluid cylinders rotates the transfer arm from the box-opening position to the closure position. The first prescribed angle is about 158°, and the second prescribed angle is about 45° from the pick-up position. A vacuum assembly is carried by the transfer arm for picking up one side and an end of the top box. The vacuum assembly includes a first arm having suction devices for engaging the side of the knock-down box in the pick-up position, and a second, pivotal arm having suction devices for engaging the end of the knock-down box in the box-opening position. The second pivotal arm includes a pivot having a displaceable pivot rod having a first position in which said pivotal arm engages the end of the knock-down box, and a second, axially displaced position corresponding to engagement with the end when the end is perpendicular to side of open rectangular box. The transfer drive includes a second drive for rotating the vacuum assembly generally 90° to rotate the box horizontally from the pick-up position to an erect vertical orientation at the closure position as the transfer arm rotates between the pick-up and closure positions. The second drive includes a belt drive connected between the base pivot and an end pivot carried near an end of the transfer arm which pivotally carries the vacuum assembly. The belt drive includes drive pulleys carried by the base pivot and the end pivot carry about which an endless belt is carried to provide a desired drive ratio to rotate the vacuum assembly generally 90° as the transfer arm is rotated substantially more than 90° between the box pick-up and closure positions. 
     The closure section includes a pressure foot assembly which includes a pressure foot and first actuating means for moving the pressure foot vertically between a retracted position and a lowered position wherein the pressure foot engages an inside bottom of the box in the closure section to exert pressure on the box for closure of the end and side flaps. There is a second actuating means for moving the pressure foot horizontally from the closure section, through the taping section, to an exit section. The closure section includes an end flap closure means for closing the end flaps of the box, and a side flap closure means for closing the side flaps of the box. The end flap closure means includes a movable bar which engages the end flaps and fits within a gap defined by adjacent edges of the side flaps for holding the end flaps closed while the side flaps are being closed upon end flaps. There is a first closure actuating means for moving the bar to engage and close end flaps. The side flap closure means includes an elongated closure member engaging the side flaps over a substantial length of the side flaps. There is a second closure actuating means for moving the elongated closure member to engage and close the side flaps upon end flaps. The pressure foot then moves the box with closed flaps over the taping section where the flaps are taped closed. The box is then released from the exit section when the product feed line demands an empty box. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The construction designed to carry out the invention will hereinafter be described, together with other features thereof. The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein: 
     FIG. 1 is a side elevation of a box erector according to the invention illustrating an inventory section and a transfer section of the invention; 
     FIG. 2 is a top plan view of a box erector according to the invention illustrating a flap closure section, a taping section, and an exit section thereof; 
     FIG. 3 is a side elevation illustrating a transfer arm assembly and a vacuum assembly according to the invention; 
     FIG. 4 is a sectional view taken along line 4--4 of FIG. 3; 
     FIG. 5 is a side elevation illustrating a box erector wherein an erected box is being processed through a flap closure section, a taping section, and an exit section by use of a pressure foot according to the invention; 
     FIG. 6 is a side elevation illustrating a flap closure section of a box erector according to the invention; 
     FIG. 7 is an end view of a flap closure section of a box erector according to the invention; 
     FIG. 8 is a side elevation of an exit section of a box erector according to the invention; 
     FIG. 9 is an end view of an exit section of a box erector according to the invention; 
     FIG. 10 is a side elevation of a ratchet assembly for indexing an inventory platform which vertically advances an inventory of knock-down boxes for erection according to the invention; 
     FIG. 11 is a perspective view of a ratchet assembly and drive therefore according to the invention; and 
     FIG. 12 is a sectional view taken along line 12--12 of FIG. 1. 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring now in more detail to the drawings, FIG. 1 is a side view of a box erector according to the invention which includes a frame 10 having vertical frame elements 12 and various horizontal frame elements 14 including base frame elements 14a. The box erector has five major sections. There is an inventory section 20, a transfer section 22, a flap closure section 24, a taping section 26, and an exit section 28. 
     Inventory section 20 includes a vertical stack of cardboard boxes 30 carried on a platform 31 whereby a top box 30a may be picked up from the top of the inventory. A ratchet mechanism 32 indexes the inventory to maintain a constant height H for each box erection cycle. A height sensor valve 34 senses the presence of top box 30a when in a proper position for being picked up by a transfer arm assembly, designated generally as A. Boxes 30 are held in alignment by an alignment means provided by a plurality of guide bars 34. Preferably, there are a pair of guide bars 34 spaced along the bottom of the box and a single guide bar along the sides of the box (FIG. 2). There are no guide bars across a side 10a of frame 10 since access to the platform needs to be unrestricted for loading of boxes from the side. 
     As can best be seen in FIGS. 10 and 11, indexing means for raising platform 31 is provided by a ratchet mechanism 32 which includes a pair of overriding clutches 36 and 38 mounted in two separate split housings 40, and which rotate on a drive shaft 42. Drive shaft 42 turns a sprocket 44 that drives a chain 46 which raises and lowers platform 31. For this purpose, chain 46 has a first end 46a attached to a flange 48a attached to a bearing block 48 which slides on a guide post 50. A second end 46b of chain 46 is attached on a rear side to a second flange 48b attached to bearing block 48. In this manner, bearing block 48 is raised when a front run of chain 46 is lowered. There are a pair of bearing blocks 48 which are affixed to platform 31 a diagonal corners, both of which slide on a vertical slide post 50. Sprocket 44 moves inventory platform 31 up in precise increments under the action of the overriding clutches 36 and 38. Overriding clutch 36 acts as a lock in allowing shaft 42 to rotate only in a clockwise direction. Overriding clutch 38 acts as a driver in rotating shaft 42. Each split clutch housing 40 includes a first clutch housing arm 40a and a second clutch housing arm 40b. The clutch housing and clutch arms are split at 40c. A ratchet housing 52 rotatably supports shaft 42 and the overriding clutches together with split clutch housings 40. A double actuating air cylinder 54 is affixed to a bottom part of ratchet housing 52 at a pivot 52a. Air cylinder 54 includes a piston rod 54a attached to clutch housing arm 40a of drive clutch 38 at a clevis 54b. Cylinder 54 rotates clutch housing arm 40a as piston rod 54a extends to rotate shaft 42 counterclockwise through clutch 38 (as viewed in FIGS. 10-12). Clutch arm 40a of locking clutch 36 is affixed to a side of ratchet housing 42 by a bolt 42a so that locking clutch 36 prevents shaft 42 from rotating in an opposite direction between drive strokes of piston 54a and clutch 38. Each of the split clutch housings 40 has a toggle linkage lock 56 which clamps the split clutch housing arms 40a and 40b together in a press fit so that they move as one piece. Toggle linkage lock 56 includes linkage 56 which pivots about a pivot 56a attached to arm 40a, as can best be seen in FIG. 11. There is a lock pin 56b carried by housing arm 40b. Movement of the linkage 56 to a vertical position, as shown, causes arms 40a and 40b to be forced towards another by action of tapered V-groove 56c formed in linkage 56. This causes the split 40c and split housing 40 to close whereupon clutch 38 is driven by movement of arm 40a, and clutch 36 free wheels. On the down stroke of piston 54a, clutch 38 free wheels and clutch 36 holds shaft 42 against rotation. For purposes of engaging and disengaging the toggle linkage lock, there is a knob 56d carried atop each linkage. Thus, clutch 36 provides a latch means which latches the indexing means and platform 31 at box pick-up height H. Means for releasing the latch means provided by clutch 36 is provided by releasable toggle linkages 56 which allow platform 31 to descend for reloading of boxes. During descent, brake means for braking the descent will be provided by cable cylinder 58. This allows normal ratcheting action by the ratchet mechanism and lifting of the inventory platform in precise increments. Releasing the toggle linkage lock allows expansion of a hole diameter 56a, thus freeing the clutch within the housing so it can now rotate in an opposite direction against which the clutch had been previously locked so that the inventory platform may be lowered. Clutch 38 drives shaft 42 in rotation to advance sprocket 44 and inventory platform 30 in a precise increment. Overriding clutch 36 is installed on shaft 40 to clutch an opposite rotational direction so that it free-wheels about shaft 42 as shaft 42 is rotated by engaged clutch 38. As piston rod 54a is retracted, clutch 38 will free-wheel while clutch 36 will engage so that shaft 42 does not rotate in an opposite direction, but is locked at that platform height. This maintains the height of inventory platform 30 to which it was lifted by the extension of piston rod 54a. Clutches 36 and 38 may be any suitable clutches such as a roller bearing clutch manufactured by Torrington Company of Torrington, Conn., as dc overriding clutches. Thus, it can be seen that ratched mechanism 32 allows inventory platform 31 to be raised in increments to maintain the correct inventory height H and when released the clutch override permits lowering the platform. Height sensor 34 is preset to operate at the correct inventory height and shuts off operation of cylinder 54 in preventing over-shoot of the inventory height. A cable cylinder 58 is attached to inventory platform 31 which serves as a break when toggle linkage lock 56 on clutches 36 and 38 is released. A throttle valve adjusts the maximum speed of the downward motion of the inventory. Cable cylinder 58 may be any suitable cable cylinder such as one manufactured by the Tol-O-Matic Corporation of Minneapolis, Minn. A carton keeper 60 is carried by frame 10 and prevents misalignment of boxes 30 as transfer arm A returns to a pick-up position allowing contact of vacuum cups with the cartons. 
     Referring now to transfer section 22, transfer means for picking up a carton from inventory, opening the carton, and placing and holding the carton in closure section 24 will now be described. As can best be seen in FIGS. 3 and 4, there is a transfer arm assembly A having a base 62 carried by frame 10 and an end pivot 64. There is a base pivot 66 carried by base 62 about which an arm 61 of transfer arm assembly A pivots by a drive means which includes a rack 68 and a pinion gear 70. There is a pair of cylinders 72 and 74 which drive rack 68 in a linear motion which rotates pinion gear 70 that is bolted onto arm 61. End pivot 64 provides the pivotal and mounting point for a vacuum assembly, designated generally as B, which includes a plurality of vacuum cups 76. Vacuum assembly B includes a first vacuum pick-up arm 78 and a second box opening arm 80 carried by a bracket 65 which is affixed to pivot shaft 64. Pick-up arm 78 includes a plurality of vacuum cups 76, and opening arm 80 includes a plurality of vacuum cups 76a. Box opening arm 80 pivots about a pivot 88 carried by brackets 65 and includes an axially displaceable pivot rod 80b which slides within bracket 81 that is affixed to a piston rod 84a of cylinder 84. Box opening arm 80 pivots inwardly to engage an end 29 of box 30. Because of the box thickness when the ends and sides are knocked down, as illustrated in FIG. 4, it is necessary to spring-load displaceable pivot rod 80b so that when the box opening arm pivots 90°, as shown in full lines in FIG. 4, the suction cup is not disturbed in its position on the end 29 of box 30. If the pivot arm did not change its length, the suction cup would be pulled inwardly upon the outward pivoting of box opening arm 80 causing the cup to lose its suction. For this purpose, there is a tension spring 80c which retracts pivot rod 80b and allows it to move outwardly during pivoting. A vacuum is applied to the suction cups through conventional fittings 82 from a vacuum source (not shown). With transfer arm A at a pick-up position, as shown in dotted lines in FIG. 1, vacuum cups 76 of pick-up arm 78 make contact with a top carton 30a. Carton height sensor valve 34 is set to insure each carton reaches this. When a vacuum is applied to vacuum cups 76, a vacuum is applied to the carton. A vacuum sensor 82a is preset to insure proper grip is maintained during this transfer and a second vacuum sensor 82 provides the same action as the carton end is pulled open by opening arm 80. If either of these sensors sense a vacuum loss during transfer and opening, the machine can be placed on hold for operator assistance. When vacuum sensor 82 senses a vacuum condition, cylinder 72 is extended fully. Cylinders 72 and 74 are double actuating air cylinders. Reaching extension allows cylinder 74 to extend which swings opening arm 80 and vacuum cup 76a onto an end 29 of the box. Vacuum sensor 82a now senses a preset vacuum on vacuum cup 76a which allows cylinder 84 to retract pulling out the carton side and ends forming a square box shape. Cylinder 84 may be any conventional double acting cylinder. At this point, a sensor 86 senses the presence of an operator 86a to let the system know cylinder 84 has retracted. The retraction signal from sensor 86 and vacuum sensor signal from 82a may be used to signal extension of cylinder 74 which moves rack 68 further upwards pivoting the opened box into closure section 24. Cable 88 is connected to pivot points 64 and 66 of pivot arm A to provide proper timing of rotation of the box from a horizontal to a vertical position for flap closure. The transfer drive means for driving transfer arm A includes a first drive means provided by rack 68 and pinion gear 70 as actuated by cylinders 72 and 74. This rotates arm A approximately 158° the box pick-up position, as shown in FIG. 1, to the box closure position wherein the box is vertically disposed at closure section 22. Intermediate the pick-up position and box closure position is the box-opening position which is approximately 79° counter-clockwise from the pick-up position. Transfer drive means includes a second drive which rotates vacuum assembly B as transfer arm A rotates from the pick-up position to the box closure position. The second drive rotates vacuum assembly generally 90° so that the box is rotated horizontally from the pick-up position to an erect vertical configuration at the closure position at closure section 22. Preferably, the second drive means includes a belt drive provided by belt 88 which encircles a drive pulley 88a affixed to pivot shaft 64 and a drive pulley 88b affixed to pivot shaft 66. Drive pulleys 88a and 88b provide a prescribed drive ratio so that vacuum assembly B rotates generally 45°  from the pick-up position to the box-opening position, and 45° from the box-opening position to the box closure position, as arm A travels 158°. Cylinder 72 is affixed to vertical frame leg 12. Cylinder 74 is affixed to piston rod 72a of cylinder 72. Piston rod 74a of cylinder 74 is attached to rack 68. Cylinders 72 and 74 provide the motion to rotate transfer arm A in two steps. First, cylinder 72 rotates the transfer arm approximately 79° from the pick-up position which allows room for end opening cylinder 84 to open the box into a square or rectangular form. At the same time, the top box is rotated 45° during travel to the box-opening position. If vacuum is lost in this function of operation, the machine will not proceed to the next sequence. Second, cylinder 74 extends only when the box-end opening cylinder 84 has retracted. 
     Referring now to closure section 24, the closure section is sequenced to close end flaps 29a and then side flaps 31a of the ends and sides, respectively, of the box. When transfer arm A positions box 30 into closure section 34, a tape cylinder 90 is actuated to extend a pressure foot assembly, designated generally as C, over the box. Tape cylinder 90 is preferably a conventional band cylinder which is available from the Tol-O-Matic Corporation. Pressure foot assembly C includes a pressure foot 92, a pressure foot cylinder 94, and a retraction and extension mechanism, designated generally as 96. Mechanism 96 includes meshing gears 96a and linkage arms 96b actuated through the gears. Cylinder 94 may be any suitable conventional double actuating air cylinder. Upon extension of tape cylinder 90 to a left-most position, as can best be seen in FIG. 5, a sensor 98 is engaged and activated which may be used as a signal to activate pressure foot cylinder 94. Actuation of pressure foot cylinder 94 extends pressure foot 92 into the open box, as can best be seen in FIGS. 5-7. The pressure foot stabilizes the box during flap closure. When the pressure foot is extended into a box, end flap cylinders 100 are actuated which closes end flaps 29a. Piston rod 94a has an end connected to extension/retraction mechanism 96 at a pivot 94b. When pressure foot 92 is extended into an open box, pivot end 94b is retracted to the left. This position may be sensed by a sensor 102. The signal from sensor 102 may be utilized to actuate cylinders 100 to close end flaps 29a. For this purpose, cylinders 100 include piston rods 100a attached to a clevis 100b that is attached to a pivot rod 102 to which is affixed a closure rod 102a which provide an end flap closure means. Extension of cylinders 100 causes rod 102a to pivot counter-clockwise and engage end flaps 29a raising them to a horizontal position, as can best be seen in FIG. 6. Cylinders 100 may be any conventional double actuating air cylinder. A sensor 104 and operator 104a may be utilized to sense extension of cylinders 100, as can best be seen in FIG. 2. 
     The signal from sensor 104 may be utilized to actuate a side flap closure means which includes a pair of cylinders 106 which pivot arms 108 that carry side plates 110 which extend across the width of side flaps 31a, as can best be seen in FIG. 7. It is to be appreciated that closure bars 102a are provided in the form of a simple narrow bar while closure plates 110 are provided having a width about the same as the width of side flaps 31a. This provides the expedient that end flap bars 102a may be accommodated between the opposing edges of side flaps 31a to hold end flaps 29a horizontal while side flaps 31a are being closed by cylinders 106, as can best be seen in FIG. 7. A stationary sensor 112 and a movable operator 112a carried by a pivot shaft 108a provide a signal to indicate the side flaps have been closed (FIG. 2). The side flap closure signal may be used to actuate tape cylinder 98 to retract the cylinder moving pressure foot assembly C and box 30 to the right, as can best be seen in FIG. 5. As box 30 moves to the right, it moves across tape section 26. 
     As can best be seen in FIG. 2, tape section 26 includes tape applicator 120, side squeeze rolls 122, and idler rolls 124. Pressure foot 92 extended into the open box, within its side flaps closed, the pressure foot moves the box, with pressure applied to the bottom flaps, over tape applicator 120. Before the box strikes the tape applied by tape applicator 120, squeeze rollers 122 force the bottom flaps together which eliminates the gap between the two side flaps to insure a tight seal of the bottom. Side squeeze rollers 122 also act as a centering guide for the box as tape is applied to the box. As tape cylinder 90 reaches its home position, which is retracted to the right, a sensor 126 is actuated which causes pressure foot cylinder 94 to retract pressure foot 92 from the box. Tape section 26 may include a conventional taper unit manufactured by Customized Equipment Southeast, Inc. of Tucker, Ga. 
     Referring now to exit section 28, a sensor 130 may be utilized to sense the retracted position of pressure foot 92, as can best be seen in FIG. 9. In the exit section, the box is positioned so that it can be indexed into a feed system to receive a product. Exit section 24 includes an exit cylinder 132 which pushes box 30 into drop hinges 134 which provide a box release means. For this purpose, exit cylinder 132 includes a generally L-shaped arm 132a carried by the cylinder which pushes box 30 to the side over drop hinges 134 when exit cylinder 132 is extended. Drop hinges 134 allow the box to drop only when space is available on the feed system below. Space availability may be sensed by a sensor valve (not shown) on the customers feed system which can be utilized to actuate a pair of drop cylinders 136 which actuate the drop hinges 134. A pair of top flap cylinders 140 may be provided to break the crease of the top flaps so that they may be more easily closed at a subsequent step. After box 30 is dropped by drop hinges 134, a new box erection cycle will begin automatically and continue until the inventory of unfolded boxes is depleted which shuts the machine down. A sensor 142 may sense box 30 as it is dropped to a position. A sensor 144 may be utilized to sense the position of inventory platform 30 when it is empty. In this manner, signal from sensor 142 may be utilized to start a new box erection cycle and a signal from sensor 144 may be utilized to shut the machine down. 
     Preferably, the air cylinders in operation described above are done pneumatically. The sensors which have been described may be any suitable air valves such as three-way or four-way air control valves manufactured by Humphrey Products Company of Kalamazoo, Mich. Suitable air cylinders are manufactured by the Compact Air Products Corporation of Westminster, S.C., and suitable vacuum cups, sensors, and generators, are available from Vaccon Corporation of Norwood, Mass. The arrangement of a suitable pneumatic control circuit including switches, valves, and pneumatic hoses, is within the purview of one skilled on the pneumatic control art and having been taught the operation and advantages of the present invention. 
     While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.