Abstract:
For automatic unloading of soft-drink pack carriers form boxes, and depositing same into the carrier-magazine of a packaging machine. The carrier box is loaded into a bucket, from a full-box-conveyor. The bucket is pivotable, and is overturned to enable the box to be extracted from the bucket, leaving the carriers inside. The bucket is pivoted in a cradle, and the cradle is carried in a bucket-elevator, and the bucket can undergo up/down movements on the elevator. Because of the elevator, the box conveyors can be overhead, out of the way of the magazine into which the carriers are to be transferred.

Description:
The present invention represents a development of the technology described in patent publication U.S. Pat. No. 6,213,707, to which attention is directed. Many of the structures and components as described herein are explained more fully in that publication. 
    
    
     BACKGROUND TO THE INVENTION 
     The apparatus of the present invention is intended for use with certain types of packaging machines, being especially packaging machines for packaging e.g soft-drink cans into cardboard carriers. 
     These packaging machines have a carrier magazine, in which the carriers are stacked in an unopened condition. The packaging machine is arranged to pick the cardboard carriers off the magazine one by one, to unfold and open up the picked carrier so that the carrier presents e.g six receptacles, then to place the opened six-pack carrier on a conveyor, then to lower six soft drink cans into the six receptacles, and then to convey the six packs away for sale. 
     The packaging machine with which the apparatus of the present invention is mainly intended for use includes also a carrier-picker, which functions to pick the next carrier from the magazine. The carrier-picker serves to pick the as-yet-unopened carriers out of the magazine on a one-and-only-one basis. The designer has to be careful to ensure that only one carrier is picked, since picking either no carrier, or two carriers, can be highly disruptive to the operation of the packaging machine. 
     The accuracy with which the carrier-picker carries out its one-and-only-one function depends not only on the structure of the carrier-picker, but also on the manner in which the magazine presents the carriers to the carrier-picker. Simply providing that the magazine does not run out of carriers during operation is not enough: the designer should ensure that the carriers in the magazine are urged towards the carrier-picker always with the same force, or at least approximately the same force. If the stack of carriers in the magazine were pressed hard against the carrier-picker one minute, and then pressed only lightly towards the carrier-picker the next minute, that might well lead to erratic performance of the carrier-picker, and to the one-and-only-one function being compromised. 
     The apparatus of the present invention has, as a main function, the automatic replenishment of the carrier magazine with fresh carriers. The carriers are shipped and delivered to the factory in which the packaging machine is located, in cardboard shipping-boxes, and it is one of the functions of the present apparatus to extract the fresh carriers from the shipping boxes, and to insert them into the magazine. 
     It is an aim of the invention to accomplish the automatic replenishment in a manner that permits the magazine to continue to maintain an approximately-constant force on the carrier picker, during replenishment. It would not be acceptable for the replenishment apparatus to require the packaging machine to be stopped, in order to permit routine replenishment. 
     It is also an aim of the invention to provide an apparatus which can be adapted for use with a number of different kinds of magazines and packaging machines. 
     It is also an aim to provide an apparatus that, having been fitted to a particular machine, can be adjusted for different requirements. For example, the packaging machine may be set up to package six-packs of beer bottles on Monday, and to package twelve-packs on Tuesday. Not only are the carriers different, but Tuesday&#39;s carriers might also be orientated, in their shipping boxes, upside-down with respect to Monday&#39;s. 
     It is also an aim to provide an apparatus which will enable trouble-free replenishment of carrier magazines over a long service period. Since factory machinery can be dangerous for operatives and others, it is also an aim to provide an apparatus in which the possibility of injuries to workers (and damage to the apparatus) is minimised. 
     GENERAL FEATURES OF THE INVENTION 
     In the apparatus shown in U.S. Pat. No. 6,213,707, the shipping box suction head was conveyed on a travelling track, and the movements of the bucket included only pivoting about a fixed pivot. In the present apparatus, the bucket not only pivots, but travels vertically, on a bucket-elevator. The suction-head may also be on an elevator, but, as will be described, the required motions of the suction-head can now be accommodated by a swing-lever about a fixed pivot axis. 
     In the present apparatus, the carriers are extracted from the box by pulling the box straight up out of the bucket. In the present apparatus, preferably the box is held steady by the suction head, and the bucket is lowered in the elevator, to achieve the linear extraction motion relatively between the box and the bucket. The bucket moves downwards in a linear motion, preferably with no arcuate component. The movement of the bucket on the elevator is vertical, or nearly vertical. 
     The inclusion of the bucket-elevator means that the conveyor for the incoming full boxes of carriers, and the conveyor for the outgoing empty boxes, are well above the height of the magazine. Generally, the magazine is at e.g waist height, since the magazine is a critical component that needs to be carefully set up by the assembly-line setter. Of course, the conveyors also are subject to being adjusted and maintained, but it is recognised as preferable not to compromise the access and space around the magazine, and this preference can be accommodated when the conveyors can be positioned well above the magazine. 
     In the present apparatus, the full-box-conveyor does not need to be within arc-swing distance of the magazine, as was the case in &#39;707. The empty-box-conveyor does have to be within arc-swing distance of the elevator, but that is not a very demanding restriction, by comparison. 
     Of course, the box conveyors should not be too far up above the magazine. The carriers go through the carrier-picker at a rate of, say, one per second. There may be as few as fifty carriers in a box, which means the cycle time for replenishing the magazine with fresh carriers has to be accomplished well within fifty seconds. But having the bucket travel through a vertical height of a meter or two is easily accommodated within the allowable cycle time. 
     The carrier-picker at the end of the magazine of carriers must pick carriers from the magazine on a one-and-only-one basis. The accuracy of the carrier-picker is affected by the force with which the carriers are pressed against the carrier-picker. That force should be kept reasonably constant—and it is not acceptable for the carrier picker to stop picking carriers from the magazine while the magazine is being replenished. The row of carriers is biassed towards the carrier picker by means of weights, or a pneumatic ram, or the equivalent. But the biassing device has to be withdrawn during replenishment. As noted in U.S. Pat. No. 6,213,707, there is enough compressive resilience in the row of carriers on the magazine to keep the carriers pressing constantly against the carrier picker, even though the biassing device has been withdrawn, if hooks or fingers are provided to stop the row of carriers from easing away from the carrier-picker. 
     The force with which the carriers press against the carrier-picker can be maintained more nearly constant, if the quantity of carriers per box is small. Thus, frequent transfers of a small number of carriers to the magazine is preferred over the less frequent transfer of a larger number. It is preferred that the boxes should contain, typically, no more than about two hundred carriers—because then the difference in the magazine, between “just filled”, and “filling now required”, might be too much, whereby the carrier picker might start to function erratically. On the other hand, the boxes should not contain less than about fifty, or cycle times become too rapid and jerky for the kinds of motions required. 
     Whatever the number of carriers in a box, preferably the whole quantity should be transferred to the magazine in one go. It can be awkward to handle the carriers if the quantity has to be split after taking the stack out of its shipping box. 
     The arrangement of the apparatus as described herein permits the pivot axis of the bucket to run through the centre of gravity of the loaded bucket, or close to it. This keeps centrifugal forces on the contents of the bucket to a minimum, permitting fast motions. It also means that the arc-swing of the bucket about its axis is minimised, which is useful in tight spaces. It also means that no counterweights are needed for the bucket. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     By way of further explanation of the invention, exemplary embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
     FIG. 1 is a diagrammatic pictorial view of an apparatus that embodies the invention. 
     FIG. 2 is the same view as FIG. 1 of the apparatus of FIG. 1, in the same position as FIG. 1, but omitting some of the components of the apparatus. 
     FIG. 3 is the same view as FIG. 2, but shows the apparatus at a later stage of operation. 
     FIG. 4 is the same view as FIG. 2, but shows the apparatus at a later stage of operation. 
     FIG. 5 is the same view as FIG. 2, but shows the apparatus at a later stage of operation. 
     FIG. 6 is the same view as FIG. 2, but shows the apparatus at a later stage of operation. 
     FIG. 6 a  is the same view as FIG. 1, but shows the apparatus at the same stage as FIG.  6 . 
     FIG. 7 is the same view as FIG. 1, but shows the apparatus at a later stage of operation. 
     FIG. 8 is the same view as FIG. 1, but shows the apparatus at a later stage of operation. 
     FIG. 9 is the same view as FIG. 1, but shows the apparatus at a later stage of operation. 
     FIG. 10 is the same view as FIG. 1, but shows the apparatus at a later stage of operation. 
    
    
     The apparatuses shown in the accompanying drawings and described below are examples which embody the invention. It should be noted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific features of exemplary embodiments. 
     As mentioned, attention is directed to U.S. Pat. No. 6,213,707. The apparatus shown in the accompanying drawings is intended to be used for similar purposes to those of the apparatus depicted therein. 
     The apparatus  20  includes a full-box-conveyor  23 , on which are located dozens of boxes  24 , each box containing a respective batch  25  of cardboard carriers  26 . The senior box  24 S rests against a stop  27  of the full-box-conveyor  23 . The apparatus includes a box-motor, in the form of a ram  28 , for driving the senior box  24 S off the full-box-conveyor  23 , and into a bucket  29 . 
     The bucket  29  has six panels, being the front, back, left, right, top, and bottom panels. The orientation designations—front, back, left, right, top, bottom—are made from the viewpoint of an observer in the senior box  24 S abutting the stop  27  on the full-box-conveyor  23 , looking towards the bucket. In the following descriptions, the panels of the bucket are called by these same designations, even after the bucket  29  is moved and rotated; 
     The left panel L, the right panel R, and the back panel B of the bucket  29  are solid, in the sense that those panels are, and remain, closed. These panels L,R,B are closed to the extent that carriers  26  within the bucket cannot pass out of the bucket through those panels; and carriers cannot be passed into the bucket, through those panels. 
     The top panel T, under panel U, and front panel F of the bucket  29  can be opened and closed, and are designated herein as open/closable panels of the bucket. Each of the open/closable panels includes left and right operable doors  30 TL, 30 TR;  30 UL, 30 UR;  30 FL, 30 FR (being referenced  30  collectively). The pair of doors  30  that comprises one of the panels of the bucket can be operated to an open position, in which that panel of the bucket is open enough to let the box  24  (and the carriers  26  inside the box) pass in or out of the bucket through that panel; and the doors can be operated to a closed position, in which that panel is closed enough to prevent a box and carriers within the bucket from passing out of the bucket, through that panel. 
     It may be noted-that none of the panels of the bucket  29  is open, in the sense that the panel cannot be operated to a closed condition. 
     The pairs of doors  30  are opened and closed by means of rams, which are indicated diagrammatically by the motion arrows  32 F, 32 U, 32 T. The opening and closing of the doors is under the control of a computer, or operations-controller, of the apparatus. 
     The bucket  29  is mounted in a bucket-cradle  34 . The bucket is pivotable-about a pivot axis  35 , by operation of a pivot-motor  36 , with respect to the bucket-cradle  34 ; but apart from that, the bucket is constrained against movement in all modes relative to the bucket-cradle. The pivot-axis  35  lies on a line that is parallel to the plane of the carriers  26  in the senior box  24 S, and runs through the side panels L,R of the bucket  29 . 
     The bucket-cradle  34  is mounted for up/down sliding on a bucket-elevator  37 . The bucket-elevator includes a tower  38 , fixed to the frame of the apparatus, and having a guide-track comprising two pillars  39 . The bucket-cradle  34  is fitted with corresponding guide-slippers  40 , whereby the bucket-cradle can slide up/down with respect to the tower  38  of the bucket-elevator, but cannot move in any other mode relative to the tower. The bucket-cradle is driven up/down the bucket-elevator by means of a cable and pulley arrangement  42 , powered by an elevator-motor  43 . 
     The apparatus includes a magazine  45 , in which the carriers are assembled prior to being picked off, one by one, by a carrier-picker, and fed into the packaging machine (not shown). The magazine  45  as shown in FIG. 1 is arranged in a carriers-upright-in-a-row configuration, in that the carriers are standing upright, on their edges, in the magazine. The carrier-picker (not shown) lies at the left end of the magazine, and the carriers may be urged gently in that direction by a weight system, similar to that shown in FIG. 4 of &#39;707. Alternatively, as here, the magazine includes a magazine-ram  46 , which applies a gentle load, pressing the row of carriers to the left, against the carrier-picker. Of course, the magazine-ram  46  has to be withdrawn, in order to create a space into which the fresh batch of carriers can be inserted. 
     When a sensor (not shown) detects that the magazine needs replenishing, a finger or hook  47  is actuated, which holds the top edge of the last carrier. (There is a corresponding actuable hook (not shown) in the platform  48  of the magazine  45 , which holds the bottom edge of the last carrier.) A row of a hundred, or a few hundred, carriers arranged in the magazine is quite resilient, whereby, without the hook  47 , the row would expand and ease back along the magazine (i.e to the right) a considerable distance. With the hooks holding the row against the carrier picker, the force of the row on the carrier-picker can remain more or less constant for at least several seconds, despite the removal of carriers at the rate of say one per second, by the picker. 
     Thus, for replenishment, the hook  47  is actuated, and the magazine-ram  46  withdrawn, after which there is a period of at least a few seconds in which to drop the fresh batch of carriers onto the platform of the magazine. Then, the magazine-ram  46  is urged forwards once more, and the hook  47  is released, and the picking continues. 
     The sequence of operations may be described as follows. FIG. 2 shows the box-motor  28  being actuated, to drive the senior box into the bucket, through the opened front panel F of the bucket. Then, the front panel F is closed by actuation of the front-motor  32 F. Next, FIG. 3, the pivot-motor  36  is actuated, to invert the bucket. Next, FIG. 4, the under-panel U of the bucket, now of course facing upwards, is opened, by actuation of the under-motor  32 U. 
     Next, FIG. 5, the elevator-motor  43  is actuated, to raise the bucket  29 , until the floor  49  of the box  24 S (which is also now facing upwards) makes contact with the vacuum cups  50 . The cups snag the floor  49  of the box, whereby, when the bucket-elevator is now lowered, FIG. 6, the bucket descends, and the box  24 S is left attached to the box-lift-off-head  52 . 
     Preferably, the under-panel U (which is still on top of the bucket), and the other open/closable panels of the bucket, should all be closed during the descent of the bucket in the bucket-elevator, to keep the carriers firmly in place in the bucket, just in case the movement of the bucket might be jerky. 
     Also, in FIG. 6, the hook  47  has been activated, and the magazine-ram  46  has been withdrawn, to create a space on the magazine  45  for receiving the batch of carriers contained in the bucket  29 . FIG. 6 a  is the same as FIG. 6, but includes the bucket-elevator. FIG. 7 shows the bucket fully lowered onto the platform. The top panel T of the bucket (now underneath) is opened, by activating the top-motor  32 T. 
     The internal width of the bucket  29  is W cm wide, which is clear over the dimension D cm of the carriers. The gap G cm between the closed doors that comprise the top panel T is larger than W, whereby the doors of the top-panel can remain closed until the bucket is actually resting against the platform  48  of the magazine. Thus, the carriers can be lowered gently onto the platform, rather than being dropped onto the platform, which might cause misalignments etc. 
     It may be noted that the doors  30  are small, in relation to the size of the bucket. The doors do not need to be large to contain and support the carriers within the bucket. Small doors have the benefit that only a small arc of movement needs to be accommodated; and small doors can be moved with small pneumatic actuators. 
     FIG. 7 also shows the transfer of the empty box onto the empty-box-conveyor  53 . The box-lift-off-head  52  is carried on a lever-arm  54 , which is operated by a swing-lever-motor  56 . The box-lift-off-head pivots between the box-snagging position (FIG. 6) and the box-discharge position (FIG.  7 ). 
     FIG. 8 shows the magazine  45  now replenished, the hook  47  withdrawn, the magazine-ram  46  back in position, the empty box  24 S being disposed of on the empty-box-conveyor  53 , and the bucket  29  being raised in the bucket-elevator  37 , ready to take on a further box of carriers. 
     One major benefit of the use of the bucket-elevator, in the apparatus as shown, is that the two box conveyors  23 , 53  are up out of the way, above the magazine, and above the packaging machine. The designer usually prefers to locate the magazine at a comfortable working height for the assembly line setters and other workers. Space is at a premium at that height, and the fact that the box conveyors can be above the magazine, because of the elevator, frees up space in this premium area. 
     Also, the box conveyors and associated rams and motors, etc, can be a safety hazard, both to setters and operatives, whereby, again, placing the conveyors way above the magazine (as is permitted by the use of the bucket-elevator), gives a safety advantage. 
     The apparatus as described is versatile as to its manner of use. As shown, the full-box-conveyor  23  and the magazine  45  are so disposed that the plane of the carriers  26  as they lie in the senior box is parallel to the plane of the carriers as they lie in the magazine. The carriers might be the same way up in the magazine as they were in the senior box; where that is the case, the bucket is inverted once prior to the box being extracted from the bucket, and then the bucket (with carriers inside) is inverted again, or re-inverted, on the way down in the bucket-elevator, before the carriers are deposited in the magazine. 
     Sometimes, the boxes are delivered with the carriers upside down in the box, relative to the position in which the carriers are to be deposited in the magazine. In that case, the second inversion or re-inversion of the bucket can be omitted. 
     In some cases, the boxes of carriers are delivered onto the junior end of the full-box-conveyor upside down, i.e the boxes travel along the full-box-conveyor with the floor of the box on top. In that case, the box can be extracted out of the top side of the bucket, without the bucket needing to be inverted. However, the apparatus is intended to cater for the more usual case, where the boxes on the full-box-conveyor are right side up, as shown. 
     As mentioned, the magazine shown in FIG. 1 is in the carriers-upright-in-a-row configuration. As shown in FIGS. 8,9 of &#39;707, the magazine may be arranged in a carriers-flat-in-a-column configuration. The apparatus as shown herein can be applied to such a magazine, in which case it will be understood that the bucket should be rotated through 90 degrees in order for the carriers to be presented correctly for deposition in such magazine. 
     When the magazine is in the carriers-upright-in-a-row configuration, the platform of the magazine need not be horizontal, but might be inclined at a (small) angle to the horizontal (as in FIG. 4 of &#39;707). In that case, the operations-controller can be programmed to rotate the bucket, as it descends in the bucket-elevator, to that same angle, to ensure trouble-free deposition. 
     As shown, the line of the pivot-axis  35  of the bucket  29 , relative to the bucket-cradle  34 , passes through the bucket from left to right, and lies within the extent of the side panels L,R of the bucket. The designer may rather prefer to align the pivot-axis to pass through the bucket from front to back. In that case, some motions that are possible with the left/right pivot-axis would be ruled out, but others would be enabled. In some cases, it might be appropriate for the boxes of carriers to reside on the full-box-conveyor with the carriers aligned at right angles to the longitudinal axis of the conveyor, rather than in line with the conveyor—in which case pivoting the bucket front-back rather than left-right, might be more convenient. 
     In order for the bucket to be rotated in the motions required in the apparatus, the pivot axis should be horizontal. If the pivot axis were e.g vertical, the bucket could not be inverted in the required manner. 
     Preferably, the panels of the bucket are made adjustable. The adjustment settings may be left entirely to the operator, but there might be a danger, then, that the bucket might be adjusted too tightly onto the shipping boxes, or not tightly enough, and it is preferred that the apparatus have a number of pre-determined configurations of the bucket, whereby the operator can quickly adjust the bucket to the configuration appropriate to the incoming carriers. 
     As shown, the frame of the apparatus is self-supporting, and can be regarded as a separate structure from the box conveyors. The carrier magazine is often built into the packaging machine, as a component thereof, rather than as a component of the present apparatus, and so the present apparatus should be designed so it can be fine-adjusted to the particular height, orientation, etc of the magazine that already exists in the packaging machine. The designer should aim to set the apparatus primarily to the magazine, and then install the full and empty box conveyors to suitable heights and orientations. However, some adjustment as to heights etc can be accommodated by control settings of the bucket-elevator and other components in the apparatus. 
     The presence of the bucket-elevator, which permits the conveyors to be overhead, i.e well out of the way of the magazine, confers the further advantage that the apparatus can be installed on most configurations of packaging-machine and magazine likely to be encountered.