Abstract:
A rotary transfer mechanism for transferring flat sleeve cartons ( 20 ) from a magazine ( 22 ) to a receiving station ( 23 ) on a conveyor ( 24 ), with opening of the cartons ready to receive end-loaded product, is characterized in that the path of suction cups ( 32 ) for holding the cartons during transfer is basically determined by a continuous stationary cam track ( 34 ) permanently engaged by a cam follower ( 37 ) on a gear segment ( 35 ) pivotally mounted on carrier means ( 29 ) rotatable by a drive shaft ( 26 ), the suction cups ( 32 ) being carried by a support shaft ( 30 ) rotatable on the carrier means and coaxial with a pinion ( 38 ) meshing with the gear segment. ( 35 ), and the support shaft being connected to a bracket ( 48 ) carrying a manifold ( 47 ) for the suction cups ( 32 ) by a crank arm ( 53 ), which is connected by a link arm ( 54 ) to a rocker arm ( 55 ) freely rotatable on the drive shaft ( 26 ). A servomotor ( 27 ) programmed by a computer (not shown) drives the drive shaft ( 26 ) through a gearbox ( 28 ) to vary the speed of the suction cups ( 32 ), especially when passing through the delivery station ( 23 ) to effect opening of the cartons ( 20 ) by movement relative to flights ( 64 ) on the conveyor ( 24 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to a rotary transfer mechanism for extracting a flat article from the discharge opening of a magazine and depositing it at a receiving station. 
     BACKGROUND OF THE INVENTION 
     Such a mechanism is described in EP-A-0331325 comprising a support member, a drive shaft rotatably mounted on and extending from the support member, means for rotatably driving the drive shaft, carrier means rotatable with the drive shaft, at least one support shaft rotatable on the carrier means substantially parallel to the drive shaft, whereby the support shaft can orbit round the drive shaft, means for controlling the rotational disposition of the support shaft with respect to the carrier means, at least one suction cup attached to the support shaft, means for producing a vacuum, means alternatively connecting the suction cup with the vacuum-producing means and the atmosphere, the means for controlling the support shaft including means causing the suction cup while connected with the vacuum producing means to contact an article at the discharge opening of the magazine, extract the article from the magazine, and transfer the article to the receiving station, whereupon the suction cup is connected with the atmosphere to release the article to the receiving station, characterised in that the means for controlling the at least one support shaft comprises on the one hand, a pinion secured coaxially to the support shaft, and an arcuate rack secured to the support member in such a position as to act upon the pinion to create a partial path of the at least one suction cup with a “node point” at the discharge opening of the magazine; and, on the other hand, a cam follower on an arm extending laterally from the support shaft, and a cam track secured to the support member and of such an operative extent as to act upon the cam follower when the arcuate rack is not acting on the pinion, the profile of the cam track being such as to cause the suction cup to move past the receiving station in the same direction as the conveyor with the article generally parallel to the conveyor. 
     Thus, the suction cup “plucks” each article from the magazine, but instead of merely dropping the article at the receiving station, the suction cup imparts to the article a major component of motion in the direction of movement of the conveyor, with consequent better placement of the article on the conveyor. The flexibility of design in suction cup path afforded by the combination of the ratio of the rack-and-pinion drive, the disposition of the rack, and the profile of the operative extent of the cam track, allows for a wide choice of article length and disposition of magazine, whilst avoiding interference between the magazine or the conveyor with the article while it is being transferred. This is particularly important when the conveyor has flights for the timed positioning of the articles in relation to a subsequent operation, such as when the article is a sleeve carton presented on the conveyor in open condition ready for end loading with a product at a subsequent station. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a simpler and more compact rotary transfer mechanism than that of EP-A-0331325. 
     Another object is to keep the fed article path beyond the perimeter of the rotating mechanism at all times, thus enabling, in a sleeve carton feeding, erecting, and end-loading machine, product to be loaded, adjacent to fed cartons, to pass unhindered beneath the mechanism. 
     A further object is to enable the mechanism to partially overhang the conveyor, thus reducing cantilevered loads and inertia of the at least one suction cup. 
     Yet another object is to provide an improved path for the fed article, particularly a sleeve carton, as compared with the path afforded by the mechanism of EP-A-0331325. 
     A still further object is to provide a programmed variable motion path for the fed article, particularly of a sleeve carton with respect to its dimensions, thus giving further carton erection improvements by optimising carton erection geometry. 
     According to the present invention, a rotary transfer mechanism for extracting a flat article from the discharge opening of a magazine and depositing it at a receiving station on a conveyor comprises a support member, a drive shaft rotatably mounted on and extending from the support member, means for rotatably driving the drive shaft, carrier means rotatable with the drive shaft, at least one support shaft rotatable on the carrier means substantially parallel to the drive shaft, whereby the support shaft can orbit round the drive shaft, means for controlling the rotational disposition of the support shaft with respect to the carrier means, at least one suction cup attached to the support shaft, means for producing a vacuum, means alternatively connecting the suction cup with the vacuum-producing means and the atmosphere, the means for controlling the support shaft including means causing the suction cup while connected with the vacuum producing means to contact an article at the discharge opening of the magazine, extract the article From the magazine, and transfer the article to the receiving station, whereupon the suction cup is connected with the atmosphere to release the article to the receiving station, characterised in that the means for controlling the at least one support shaft comprises a continuous stationary cam track, a gear segment on a pivot on the carrier means axially parallel to the drive shaft, a cam follower on the gear segment permanently engaged with the cam track, and a pinion secured coaxially to the support shaft and permanently meshing with the gear segment, the profile of the cam track being such as to act on the gear segment along one part of the track to oscillate the pinion to create a partial path of the at least one suction cup with a “node point” at the discharge opening of the magazine, and along another part of the track to partially rotate the pinion so as to cause the suction cup to move past the receiving station in the same direction as the conveyor with the article generally parallel to the conveyor. 
     Thus the carrier means needs to have a radial extent little more than the radial distance of the support shaft from the drive shaft, while the maximum radial extent of the cam track can be appreciably less, thus minimising the radial extent of the carrier means. 
     As applied to a machine for transferring flat sleeve cartons from the discharge opening of a magazine to a receiving station on a conveyor having flights, opening of the cartons, ready for end loading with a product at a subsequent station along the conveyor, is facilitated by arranging for the combined action of the means for rotatably driving the drive shaft and the means for controlling the at least one support shaft so that at the receiving station the at least one suction cup is moving in the same direction as the conveyor relatively at a slightly greater speed, whereby the relative movement between the suction cup, holding one side of a sleeve carton, and leading flights on the conveyor, which flights are abutted by the leading corner fold of the carton, is such as to effect an opening of the carton which is substantially completed before the carton is abutted by trailing flights on the conveyor to hold the carton in its fully open condition as it passes to and through a subsequent end-loading station. 
     According to a feature of special significance, the drive shaft is rotatably driven by a servomotor programmed by a computer, to afford variation in the speed of the at least one suction cup along its path through the receiving station, particularly to suit different sizes of sleeve cartons. 
     Conveniently, three support shafts are provided with two or more suction cups attached to each shaft; but two, or four or more support shafts may be provided, depending on the size of the article to be transferred and/or the spacing of articles on a conveyor; and, likewise, three or more suction cups may be attached to each support shaft, depending on the size and/or weight of article to be transferred. 
     The or each pair (or more) of suction cups is preferably carried by a cantilever from a bracket secured on one end of a crank arm the other end of which is pivoted to the support shaft, and the bracket is secured to one end of a link arm the other end of which is pivoted to one end of a rocker arm the other end of which is freely rotatable on the drive shaft, whereby as the crank arm swings the suction cups are orientated accordingly, firstly for contact with an article at the discharge opening of the magazine, and secondly as required for passage through the receiving station on the conveyor. 
     The cam track is preferably provided on a disc mounted inside a casing forming the carrier means along with the gear segment and cam follower, and the pinion, with the or each support shaft exiting through a sealed bearing, and with the drive shaft passing through the support member and coaxially through the casing via sealed bearings, from a gearbox and motor (e.g. a servomotor) to the rocker arm, thus effecting driving of the casing through the link arm, the crank arm and the support shaft; thus enabling the use of a steel cam plate with attendant accuracy and durability, steel gear segment and cam follower, and steel pinion, with permanent lubrication affording increased life expectation and potential noise reduction: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a side elevation of a rotary transfer mechanism in accordance with the invention; 
         FIG. 2  is an isometric view of the mechanism as seen from the same side as in  FIG. 1  and from downstream of the direction of conveyance of the erected cartons, with the nearer part of the casing forming the carrier means omitted; 
         FIG. 3  is an enlarged elevation of the mechanism as seen from the left-hand side of  FIG. 2  and indicating in broken lines the cam followers (not visible in  FIG. 2 ) engaged with the cam track; 
         FIG. 4  is an isometric view of part of the mechanism as seen from the opposite side to  FIG. 2  and from downstream of the direction of conveyance of the erected cartons, with the other part of the casing forming the carrier means omitted; 
         FIG. 5  is an elevation of the stationary porting plate for providing communication through ports in the rotatable porting plate shown in  FIG. 4  with suction sources (not shown) for the suction cups shown in  FIGS. 1 to 4  or for exhausting the suction cups to atmosphere during each cycle of the mechanism; 
         FIG. 6  is a fragmentary view of the mechanism mainly in section taken from the line VI-VI in Figure; 
         FIG. 7  is a diagram showing the path followed by any one suction cup in each set shown in  FIGS. 1 to 4  and  6  with the largest size of sleeve carton that can be handled by the mechanism; 
         FIGS. 8 to 17  are diagrams illustrating a sequence of positions of the mechanism as each set of suction cups approaches a magazine for collapsed sleeve cartons, through extraction and erection of a carton plucked from the magazine, to release of the erected carton between flights of a conveyor passing through a delivery station; 
         FIG. 18  corresponds to  FIG. 7  but is the equivalent diagram showing how the suction cup path can be varied to suit a much smaller sleeve carton. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 to 6 , the rotary transfer mechanism, for extracting a flat sleeve carton  20  from the discharge opening or “gate”  21  of a magazine  22  and depositing it, erected, at a receiving station  23  on a conveyor  24 , comprises a support member  25 , a drive shaft  26  rotatably mounted on and extending from the support member, means for rotatably driving the drive shaft consisting of a servomotor  27  programmed by a computer (not shown) and gearbox  28 , carrier means  29  rotatable with the drive shaft, three support shafts  30  rotatable on the carrier means substantially parallel to the drive shaft, whereby each support shaft can orbit round the drive shaft, means  31  for controlling the rotational disposition of each support shaft with respect to the carrier means, four suction cups  32  attached to each support shaft, means (not shown) for producing a vacuum, means  33  alternately connecting the suction cups with the vacuum producing means and the atmosphere, the means  31  for controlling the support shafts including means causing the suction cups  32  while connected to the vacuum producing means to contact a carton  20  at the discharge opening  21  of the magazine  22 , extract the carton from the magazine, and transfer the carton to the receiving station  23  on the conveyor  24 , whereupon the suction cups  32  are connected with the atmosphere to release the carton  20  to the receiving station  23 , characterised in that the means  31  for controlling the support shafts  30  comprises a continuous stationary cam track  34 , gear segments  35  on pivots  36  on the carrier means  29  axially parallel to the drive shaft  26 , cam followers  37  on the gear segments permanently engaged with the cam track, and pinions  38  secured coaxially to the respective support shafts  30  and permanently meshing with the gear segments, the profile of the cam track  34  being such as to act through the cam followers  37  on the gear segments  35  along one part of the track to oscillate the respective pinions  38  to create a partial path of the respecting sets of four suction cups  32  with a “node point” at the discharge opening  21  of the magazine  22 , and along another part of the track  34  to partially rotate the pinions  38  so as to cause the respective sets of four suction cups  32  to move past the receiving station  13  in the same direction as the conveyor  14  with the respective cartons  20  generally parallel to the conveyor. 
     The vacuum-producing means comprises two suction pumps (not shown) connected by pipelines  39 ,  40  to arcuate ports  41 ,  42  in a stationary valve plate  43  of the vacuum control means  33 , a rotary valve plate  44  of which is driven with the drive shaft  26 . The drive shaft is hollow and contains three tubes  45 , one for each set of four suction cups  32  to which connection is made by means of flexible pipes  46  (indicated by broken lines only in  FIG. 2  for the sake of clarity) from the nearer ends of the respective tubes  45  to manifold tubes  47  cantilevered from mounting blocks  48 . The other ends of the tubes  45  are connected by flexible pipes  49  to respective ports  50  in the rotary valve plate  44  which co-operate with the ports  41 ,  42  in the stationary valve plate  43 , to provide vacuum at the suction cups  32 , communication with the arcuate port  41  enabling a carton  20  to be plucked from the magazine  22 , the feed line  39  from the respective pump to the port  41  being switched off via a solenoid valve (not shown) to avoid plucking a carton when missing product is detected. The arcuate port  42  enables a plucked carton to be carried into the delivery station  23  on the conveyor  24  whilst the next carton is plucked from the magazine by the next set of suction cups  32 . A third arcuate port  51  in the stationary valve plate  43  is an exhaust port only, allowing vacuum to be ‘dumped’ to atmosphere, thus releasing each carton when erection is complete, and this port communicates with the atmosphere via a nipple  52  which may be provided with means to prevent ingress of contamination in very dirty atmospheres. 
     Each bracket  48  is pivoted on one end of a crank arm  53  the other end of which is secured to the respective support shaft  30 , and the bracket is secured to one end of a link arm  54  the other end of which is pivoted to one end of a rocker arm  55  the other end of which is freely rotatable on the drive shaft  26 , whereby, as the crank arm  53  swings the respective suction cups  32  are orientated accordingly, firstly for contact with a carton blank  20  at the discharge opening  21  of the magazine  22 , and, secondly, as required for passage through the receiving station  23  on the conveyor  24 . 
     The cam track  34  is provided on a plate  56  mounted inside a two-part casing  57 ,  58  forming the carrier means  29  along with the gear segments  35  and cam followers  37 , and the pinions  38 , with the support shafts  30  exiting through sealed bearings (not visible) from the casing port  57 , and with the drive shaft  26  passing through the support member  25  and coaxially through the gearbox  28  and the two-part casing  57 ,  58  via bearings  59 ,  60  to the rocker arms  55  (each on a bearing indicated by a small x), thus effecting driving of the carrier means  29  through the link arms  54 , the crank arms  53  and the support shafts  30 . The cam plate  56  is secured to the gearbox  28  by four screws  61  and houses the bearing  59 , the other bearing  60  being housed within the gearbox on a spigot  62  extending from a bevel gear  63  meshing with a bevel gear (not visible) driven by the servomotor  27 . 
     As each crank arm  53  swings the respective set of suction cups  32  are orientated accordingly, and particularly as appropriate from position A to position V in  FIG. 7  along the path traced by the common centre line of the rims of each set of suction cups, which together with eighteen intermediate positions are shown in  FIGS. 8 to 17  in relation to the attitude of a sleeve carton  20  from the discharge opening or “gate”  21  of the magazine  22  to release at the delivery station  23  on to the conveyor  24 . 
     From position A ( FIG. 8 ) to position D ( FIG. 11 ) each set of suction cups  32  follows a curving path approaching the magazine  22  and reaches a “node point” at position E ( FIG. 12 ) pushing slightly into the opening  21  of the magazine to ensure adequate contact with the foremost sleeve carton  20  for suction then to hold the nearside of the carton and pull it from the magazine as the suction cups move in a substantially straight line perpendicular to the plane of the opening  21  from the “node point” E to position H ( FIG. 15 ) when the carton comes clear from the magazine. This substantially straight line movement of the suction cups is particularly advantageous in avoiding any slipping (or attempted slipping) between the cups and the carton as the sleeve carton is caused to open until the lower or leading corner or fold is about to be pulled free of the magazine, as shown at position G ( FIG. 14 ). The carton  20  then springs back towards its collapsed condition, as indicated as it passes through positions J ( FIG. 16 ) and K ( FIG. 17 ) to position L (see again  FIG. 8 ), thus thrusting its leading corner down towards the conveyor  24  through position M ( FIG. 9 ) until first contacting leading flights  64  on the conveyor  24  at position N ( FIG. 10 ). A slightly greater speed of the suction cups  32  through positions P ( FIG. 11 ) and Q ( FIG. 12 ) results in opening of the carton  20  again, following which the speed of the suction cups matches that of the conveyor  24  whilst passing through positions R ( FIG. 13 ), S ( FIG. 14 ) and T ( FIG. 15 ) to press the carton into fully open position abutted by trailing flights  65  on the conveyor, as shown at position U ( FIG. 16 ), at which point the suction cups are about to be connected to atmosphere (by the vacuum control means  33 ) to release the carton, from which the suction cups move clear, as shown at position V ( FIG. 17 ). 
     Positions W, X, Y, Z ( FIGS. 8 to 11  respectively) show the suction cups  32  moving towards the path of substantially constant radius from position Z to position A (Figure A) in readiness for extracting and transferring another carton  20  from the magazine  22  to the conveyor  24 . 
     Only one set of flights  64 ,  65  is shown in  FIGS. 2 and 4 , a parallel set being omitted for the sake of clarity, each set being carried by chains  66 ,  67  respectively ( FIG. 3  only) guided along tracks  68 ,  69  respectively ( FIG. 1  only). 
     The support member  25  ( FIGS. 1 and 6 ) is plate-like and has weight-reducing cut-outs  70 ,  71 ,  72 , and is mounted for limited vertical movement (for adjustment of its position to suit different sizes of cartons  20 , as will be referred to again presently) by attached bearings  73  in a vertical shaft  74  upstanding from the machine base (not shown), the vertical position being set by a screw jack  75  whose screw  76  passes through a nut  77  on a bracket  78  carried by machine framing (not shown) at the top of the shaft  74 . The support member  25  is prevented from swinging about the shaft  74  by a depending arm  79  having a roller  80  engaged in a vertical channel  81  adjacent the conveyor  24 . 
       FIG. 1  also shows the support member  25  provided with an interchangeable plate  82  carrying an interchangeable magazine  22  of a size and with a delivery opening or “gate”  21  to suit a particular size of carton. 
     Variations in sizes of cartons is illustrated by the different ones shown in  FIGS. 1 ,  2 ,  7  to  17 , and  18  respectively. However, the path of each set of suction cups  32  is substantially the same for every size of carton, but the speed is varied by the computer (not shown) programming of the servomotor during the cycle, and particularly through the delivery station to ensure correct interaction between the cartons and the flights, as is illustrated by comparing the intervals between the corresponding positions in  FIG. 7  and  FIG. 18  for the largest and smallest cartons respectively. 
     Considerable advantages accrue from the combination of integers of the mechanism described above. 
     While the fixed continuous cam determines the locus of the path of the suction cups, their motion is modified by the computer software programming the servomotor velocities. Thus, the ‘overlaid’ servo motion determines the speed, including acceleration and deceleration, at which the suction cups travel around the locus path, particularly through the delivery station relative to the constant velocity of the flights. 
     The primary advantage arising from the ‘overlaid’ servo motion is to allow exactly the same rotary feeder mechanism to be used for erecting cartons of different sizes into different flight pitches. Complete feeder mechanism assemblies may be held in stock without need of knowledge as to what flight length they may be applied, as each flight length will have servo motion profile software dedicated to it. 
     A secondary advantage afforded by the ‘overlaid’ servo motion is the ability to modify the motion profile of the suction cups for particular carton sizes within a given flight length machine. Two or more distinct predetermined motion profiles may be used to modify the position of the suction cups relative to the flights for different ranges of carton size, e.g. large, medium or small. A mathematical formula may be embedded within the software that will automatically modify the motion profile software responding to carton length and width dimension inputs, which can be made in various ways, e.g., at the main operator interface, such as an LED touch screen, from a menu recipe predetermined by the machine manufacturer, from a recipe input by the customer, or a combination thereof.