Abstract:
Bottles fed continuously to a wrapping line are ordered into groups by a device comprising a conveyor belt positioned downstream of a feed station from which the bottles emerge, and a separating system, operating in conjunction with the conveyor belt, by which the advancing bottles are divided into groups before passing forward to the wrapping stations. The separating action is performed by first and second flexible bands looped around respective pulleys within vertical planes, using sets of first and second locating elements anchored respectively to the first and to the second flexible band, which are brought to bear alongside and at right angles to the conveyor belt so as to engage in contact with the bottles. The first and second locating elements are anchored removably to the relative flexible bands utilizing respective sets of attachment devices, designed in such a way that the number and mutual positioning of the elements can be varied according to the size of the bottles and the number of bottles making up the single group.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for separating continuously fed products into groups, applicable in particular to machines for packaging groups of bottles or cans in shrink film, stretch film, cardboard, etc. 
     In the art field embracing automatic machines of the type in question, the packaging line (of which the function is first to define and select a group of products and then to wrap the group, according to various criteria) includes a feed station from which bottles are supplied continuously to the line (reference is made in the present specification to bottles, albeit the invention is applicable equally to other types of containers, namely cans, jars and the like), located upstream of the machine relative to a feed path along which the bottles are caused to advance. 
     The bottles advance on a horizontal conveyor belt one behind another, ordered in columns of given width, toward an intermediate separating station that serves to establish the size of the groups of bottles being wrapped (or, the number of bottles per group) and comprises a second conveyor belt, likewise horizontal. The selected group of bottles then passes to a station where it is wrapped in a sheet of plastic film, preferably heat-shrinkable. 
     To ensure the bottles are divided up correctly into groups, the separating station is equipped by way of example with a first barrier (as in Italian patent application BO93A 000428) rendered capable of reciprocating movement in a vertical direction and positioned at the downstream end of the feed station, by which the bottles can be checked or allowed through to an intermediate pre-separating station located between the feed station and the separating station proper. The intermediate station is equipped in turn with a second vertical barrier located at a distance from the first barrier equal to the corresponding dimension of the group of bottles being selected, and positionable to match this same dimension. 
     The second vertical barrier is capable similarly of reciprocating movement timed with that of the first barrier, inasmuch as when the first barrier is in a raised position and offered to the leading face of the selected group of bottles, the second barrier is in a retracted position, and vice-versa: thus, when a certain number of bottles has passed along the conveying surface and beyond the line of the first barrier, a group of bottles is separated initially from the continuous column waiting to advance, whereas the second barrier serves simply to distance the advancing groups one from the next as they are conveyed by the remaining branch of the intermediate station toward the separating station where the group is taken up by a push bar, guided by relative chains in such a way as to engage the selected bottles from the rear immediately beyond the downstream end of the pre-separating station. 
     In a second solution reflecting the prior art (see also Italian patent application BO94A 000160), the separating station is equipped with a conveyor belt positioned between the feed station and the selfsame separating station, capable of movement in the same direction as the feed direction and at a speed higher than the speed registering at the feed station. 
     The conveyor belt is driven intermittently thanks to a clutch mechanism that allows the drive to be engaged and disengaged according to predetermined pause and feed times, so that the bottles can be directed into the separating station as required to make up the selected group; the belt operates in conjunction with a top plate positioned to check the advancing front of the column of bottles during each pause. 
     The solutions briefly outlined betray drawbacks, however, attributable in the first case mentioned to the fact that the bottles are checked twice in succession, disallowing a high output per unit of time because of the mechanical limitations imposed by the reciprocating movement of the two barriers; also, the action of the barriers tends to increase the risk of the bottles being toppled, given the high throughput speeds at the various stations. In addition, the position of the second barrier must always be adjusted when changing from one size of group to another. 
     In the second case mentioned, one drawback is a possible lack of uniformity in the movement of the bottles on the conveyor belt; more exactly, should there be insufficient frictional contact generated by the belt during initial acceleration, or breaks in continuity of the columns of bottles advancing on the belt, the correct timing between the single columns of bottles can be lost. Such problems can therefore result in the line having to be stopped while the correct feed sequence of the groups is restored. 
     In both instances, moreover, the main drawback of the device is that of its constructional complexity overall. 
     Accordingly, the object of the present invention is principally to overcome the drawbacks mentioned above by embodying a device for the separation of continuously fed products into groups that will be structurally simple and allow a correct separation of the groups while maintaining a sizeable output per unit of time, at reasonable cost. 
     Another object of the invention is to provide a device for separating products into groups that can be adapted swiftly to handle products of different sizes, so that production need not be suspended for an unduly long interval when there is a changeover in production, for example, from the packaging of small cans to the packaging of large bottles. 
     Yet another object of the invention, finally, is to provide a device for the separation of products into groups that will enable easy selection of the number of products included in each group. 
     SUMMARY OF THE INVENTION 
     The stated objects are realized according to the invention in device for separating continuously fed products into groups, typically groups of bottles, comprising a conveyor belt, looped around a set of power driven pulleys and affording a horizontal top branch establishing a feed path along which to advance at least one column of bottles in a given direction and at a predetermined speed, positioned downstream of a feed station from which bottles are directed continuously along a predetermined feed direction coinciding with the conveying direction of the belt; also separator means operating in conjunction with the conveyor belt, by which the bottles are taken up from the feed station and ordered into groups before advancing toward other production line stations, incorporating at least one first flexible band looped around respective power driven pulleys and occupying a vertical plane, positioned alongside the conveyor belt and affording a horizontal top branch driven in the same direction as that of the conveyor belt at a first variable speed, and at least one second flexible band looped around respective power driven pulleys and occupying a vertical plane, positioned alongside the first flexible band and affording a horizontal top branch driven in the same direction as that of the conveyor belt at a second variable speed; and pluralities of first and second locating elements anchored to the first and second flexible bands, positionable orthogonally and adjacent to the conveyor belt when carried along the horizontal top branches of the respective flexible bands in such a way as to engage in contact with the bottles advancing on the belt. 
     Advantageously, the device further comprises a first and a second plurality of attachment devices associated respectively with the first and second flexible bands, by means of which the first and second locating elements can be anchored removably and in such a way as will allow of varying the number and mutual positioning of the selfsame first locating elements on the first flexible band, and the second locating elements on the second flexible band, according to the size of the bottles and the number of bottles making up the single group. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: 
     FIG. 1 illustrates a device according to the present invention for separating products into groups, associated with a packaging machine shown only in part, viewed in elevation and with certain parts omitted better to reveal others; 
     FIG. 2 is a detail of the device as in FIG. 1, illustrated schematically and viewed in a first operating configuration; 
     FIG. 3 is a detail of the device as in FIG. 1, illustrated schematically and viewed in a second operating configuration; 
     FIG. 4 shows the device of FIG. 1 viewed in plan from above; 
     FIG. 5 illustrates a portion of the device as in FIG. 1, enlarged and in perspective; 
     FIG. 6 is an enlarged detail of the device as in FIG. 1; 
     FIGS. 7,  8  and  9  are schematic side elevations showing the device of FIG. 1 in a succession of respective operating steps. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the accompanying drawings, the invention relates to a device, denoted  1  in its entirety, for separating continuously fed products into groups. 
     Such a device  1  will be associated generally with a machine, illustrated only in part, for packaging groups of products P consisting typically of cans or bottles; the machine comprises a feed station  2  from which the products P in question, indicated as bottles in the specification and the accompanying drawings, are advanced in a continuous succession along a predetermined feed direction denoted A. 
     The device  1  according to the present invention comprises at least one conveyor belt denoted  3 , looped around a set of power driven pulleys  4 , of which a horizontal top branch  5  serves to establish a feed path B for at least one column of bottles P caused to advance along a predetermined direction C and at a predetermined speed V. 
     The conveyor belt  3  is placed at a downstream end of the packaging machine feed station  2 , considered relative to the feed direction A. 
     The direction C followed by the bottles along the feed path B established by the conveyor belt  3  is the same as the direction A followed through the feed station  2 , so that the bottles P emerging from the selfsame feed station  2  proceed straight toward other stations located downstream of the separator device  1  and not illustrated in the drawings. 
     In a preferred embodiment, as illustrated in FIG. 4, the separator device  1  will comprise a plurality of parallel conveyor belts  3 , varying in number according to the width of the leading face presented by the products P and set apart one from another to establish corresponding gaps  5 . 
     The bottles P are directed onto the belts  3  one behind the next, ordered in respective columns. 
     The device comprises separator means  6  operating in conjunction with each conveyor belt  3 , of which the function is to direct the bottles P from the feed station  2  to the successive stations, arranged in groups of predetermined size or number. 
     In particular, such separator means  6  comprise at least one first flexible band  7  looped around power driven pulleys  8 , occupying a vertical plane and flanking the conveyor belt  3 . The flexible band  7  in question presents a horizontal top branch  7   a  driven in the same direction as the conveyor belt  3  at a first variable speed V 1 . 
     More exactly, the first flexible band  7  is looped around a first pulley  8   a  occupying a position near the feed station  2  and a second pulley  8   b  occupying a position downstream of the first pulley  8   a , in relation to the conveying direction C. 
     The separator means  6  further comprise at least one second flexible band  9  embodied identically to and flanking the first flexible band  7 . 
     In effect, the second flexible band  9  is similar to the first, looped within a vertical plane around respective pulleys  10   a  and  10   b  of which at least one is power driven, and presenting a horizontal top branch  9   a  driven in the same direction as the conveyor belt  3  at a second variable speed V 2 . 
     In a preferred embodiment, as illustrated in FIG. 4, the device  1  includes two first flexible bands  7 , each flanking the set of conveyor belts  3  on one respective side, and two second flexible bands  9 , each flanking the set of conveyor belts  3  on one respective side, internally of the first flexible bands  7 . 
     The pulleys  8   a - 8   b  of the first flexible bands  7  and the pulleys  10   a - 10   b  of the second flexible bands  9  are interconnected permanently by way of two respective shafts  11  and  12 . 
     More exactly, as illustrated in FIG. 4, the two first pulleys  8   a  of the two first flexible bands  7  are keyed to a first shaft  11  driven in rotation by a first brushless motor  13   a , whilst the two first pulleys  10   a  of the two second flexible bands  9  are coupled freely to the first shaft  11 , for example by way of ball bearings. 
     In like manner, the two second pulleys  10   b  of the two second flexible bands  9  are keyed to a second shaft  12  driven in rotation by a second brushless motor  13   b , whilst the two second pulleys  8   b  of the two first flexible bands  7  are coupled freely to the second shaft  12 , for example by way of ball bearings. 
     The first and second brushless motors  13   a  and  13   b  constitute drive means  13  by which the pulleys  8  and  10  are set in rotation. 
     To advantage, as illustrated in FIGS. 5 and 6, each of the flexible bands  7  and  9  takes the form of a chain  14  with articulated links  15 , and the pulleys  8   a ,  8   b ,  10   a  and  10   b  are sprockets. 
     The device  1  also comprises a plurality of first locating elements  16  anchored to the first flexible band  7  which, when passing along the horizontal top branch  7   a , are positioned orthogonally and adjacent to the conveyor belt  3  in such a way as to engage in contact with the bottles P. 
     Similarly, the device  1  comprises a plurality of second locating elements  17  anchored to the second flexible band  9 , positioned likewise orthogonally and adjacent to the conveyor belt  3  when passing along the horizontal top branch  9   a  in such a way as to engage in contact with the bottles P. 
     More exactly, each of the locating elements  16  and  17  consists in a pair of rods  18  mounted to the respective flexible bands  7  and  9  in such a manner that when the bands  7  and  9  are in motion, the two rods  18  can be caused to draw cyclically alongside the two opposite edges of each conveyor belt  3 . In embodiments of the device  1  comprising an array of conveyor belts  3 , the rods  18  will pass along the gaps  5  created between the selfsame belts  3 . 
     The width of the single belt  3  is less than the diameter of the single bottle P, thereby enabling contact between the bottles P and the rods  18  as these are brought to bear alongside the horizontal top branches of the belts  3 . In particular, each rod  18  will occupy a recess O created between each two successive bottles (see FIG.  4 ). 
     The locating elements  16  and  17  are anchored as aforementioned to the flexible bands  7  and  9 , and accordingly, the device  1  according to the present invention comprises a first plurality of attachment devices  19 , each associated with the first flexible bands  7  and able to carry one of the first locating elements  16 , also a second plurality of attachment devices  20  entirely similar to the first plurality of devices  19 , associated with the second flexible bands  9 . 
     Importantly, the locating elements  16  and  17  are anchored removably by the attachment devices  19  and  20  to the corresponding flexible bands  7  and  9 , so as to allow of varying the number and changing the mutual positions of the first and second locating elements  16  and  17  on the bands  7  and  9  according to the dimensions of the bottles P and the number of bottles in each group. 
     Advantageously, as in the example illustrated, the first and the second pluralities of attachment devices  19  and  20  each present respective first devices  19   a  and  20   a , second devices  19   b  and  20   b , third devices  19   c  and  20   c  and fourth devices  19   d  and  20   d  ordered in sequence along the developable length of the respective flexible bands  7  and  9  (FIGS.  2  and  3 ). 
     The spacing between successive devices  19  and  20  on a given flexible band  7  and  9  is calculated on the basis of the minimum and maximum diameters of the products being separated into groups. 
     In particular, each of the flexible bands  7  and  9  is of predetermined developable length, denoted L, and the attachment devices  19  and  20  are positioned along this same length after the following manner: the second attachment device  19   b - 20   b  of the four, at a distance equivalent to ⅓ the length L of the flexible band  7  and  9  as measured from the first device  19   a - 20   a ; the third attachment device  19   c - 20   c  at a distance equivalent to ⅙ the length L of the relative band  7  and  9  as measured from the second device  19   b - 20   b ; and likewise the fourth attachment device  19   d - 20   d  at a distance equivalent to ⅙ the length L of the relative band  7  and  9  as measured from the third device  19   c - 20   c.    
     In the example illustrated, the chain providing each of the flexible bands  7  and  9  is made up of seventy-two links. 
     The attachment devices  19  and  20  are positioned thus on the respective chains  7  and  9 : the second attachment device  19   b - 20   b , distanced by twenty-four links  15  from the first device  19   a - 20   a ; the third attachment device  19   c - 20   c  distanced by twelve links from the second device  19   b - 20   b ; and the fourth attachment device  19   d - 20   d  distanced by twelve links from the third device  19   c - 20   c.    
     Each attachment device  19  and  20  making up the first plurality and the second plurality comprises a first elongated plate  21  extending between the two respective flexible bands  7  and  9  and passing beneath the horizontal top branch  5  of the conveyor belt  3  (see FIG.  5 ). 
     The device  1  also comprises a plurality of second elongated plates  22 , each associated removably with a respective first elongated plate  21  by means of conventional fasteners, typically screws or bolts. 
     The rods  18  are attached to each of the second elongated plates  22 , projecting from the relative first and second plates  21  and  22 . 
     More exactly, the second elongated plate  22  is fashioned with a plurality of sockets  23 , ordered symmetrically in relation to the conveyor belts  3 . The rods  18  can be engaged removably in these same sockets  23 , in such a way as to allow of varying the distance between them and thus adapting their positions to the diameter of the product P being handled. 
     Each of the attachment devices  19  and  20  further comprises an articulated mechanism  24  interposed between the respective flexible band  7  and  9  and the respective first elongated plate  21 , such as will allow the rods  18  to be oriented in relation to the flexible band  7  and  9  during the movement of the bands in the direction followed by the conveyor belts  3 . In particular, the mechanism  24  is able to shift the rods  18  between a position disposed at right angles to the flexible bands  7  and  9  and perpendicular to the conveyor belt  3 , engaging in contact with the bottles P as these advance on the horizontal top branch  5 , and a position disposed tangential to the flexible band  7  and  9 . 
     More exactly, the rods  18  are disposed at right angles to the flexible band  7  and  9  when advancing along the rectilinear branches of the relative loop, and tangential to the flexible band  7  and  9  when following the curvilinear trajectory around the pulleys  8   a ,  8   b ,  10   a  and  10   b.    
     Referring to FIG. 6, each mechanism  24  includes a rod  25  of which a first end  25   a  is hinged to a first link of the chain  14  and a second end  25   b  is hinged to the first end  26   a  of a rocker  26 . The rocker  26  is anchored by way of a central fulcrum pivot  26   b  to a second link, remote from the first link, and presents a second end  26   c  opposite from the first end  26   a , to which one end of the first elongated plate  21  is attached. 
     Lastly, the device  1  according to the invention includes suitable control means  27  (see FIG. 4) that comprise a processing unit  28 , data input means  29  and display means  30  both connected to the processing unit  28 , and a control unit  31  connected to the processing unit  28  and to the drive means  13  of the pulleys  8  and  10 . 
     In a preferred embodiment, data input means  29  would consist in a keyboard and display means  30  in a liquid crystal panel. 
     In operation, the keyboard  29  is used to enter the diameter or some other parameter correlated to the transverse dimension of the bottle P, also the number of bottles P per group. 
     Once the necessary calculations have been made by the processing unit  28 , the control means  27  will determine the number of locating elements  16  and  17  to be utilized for each flexible band or pair of bands  7  and  9 , and the attachment devices  19  and  20  to which the individual elements  16  and  17  must be attached. This output information is presented in the liquid crystal display  30 . 
     Depending on the size of the group of products to be separated, use will be made typically of three locating elements  16  and  17  fitted to the first, second and fourth attachment devices  19   a - 20   a ,  19   b - 20   b  and  19   d   20   d , as indicated in FIG. 3, or of just two locating elements  16  and  17 , fitted to the first and third attachment devices  19   a - 20   a  and  19   c - 20   c , as indicated in FIG.  2 . 
     Thereafter, the processing unit  29  calculates the relative position between the locating elements  16  and  17  of the first and second flexible bands  7  and  9  and pilots the control unit  31  to position them, through the agency of the brushless motors, before the machine is started up. 
     Supposing that three locating elements  16  and  17  are used, fitted to the first, second and fourth attachment devices  19   a - 20   a ,  19   b - 20   b  and  19   d - 20   d , the device  1 , once in operation, will function in the manner now to be described. 
     Bottles P are directed continuously from the feed station  2  onto the conveyor belts  3  in uniformly ordered columns. 
     As the machine is started up, the first bottles P to run onto a first portion of each belt  3  will be taken up and advanced along the predetermined feed direction A at the predetermined speed V of the selfsame belt  3 . 
     One of the locating elements  16  associated with the first flexible band  7 , for example that fitted to the first attachment device  19   a , advances at a speed V 1  lower than the speed V of the belt  3  and consequently intercepts the first bottle P, slowing it down to the lower speed V 1  and causing it thus to slip on the belt  3 . The bottles P of the column continue to advance at the speed V 1  of the first locating element  16 , with no breaks opening up between them (see FIG.  7 ). 
     At this point, the rods  18  of a second locating element  17  belonging to the second flexible band  9 , for example the rods  18  associated with the first attachment device  20   a , will rotate upward around the pulley  10  and locate between the bottles P. The locating element  17  in question is accelerated in such a way that a given component of its speed V 2 , measured along the conveying direction C of the belt  3 , will substantially match the speed V 1  of the locating element  16  associated with the first flexible band  7 . The rods  18  of the second locating element  17  are also oriented by the articulated mechanism  24  in such a way as to assume a vertical position on making contact with the bottles P. 
     A group of bottles P is thus selected between the first and second locating elements  16  and  17 , and advanced a given distance along the belt  3  together with the selfsame elements  16  and  17  at a speed V 1  and V 2  lower than the speed V of the belt  3  (see FIG.  8 ). 
     Thereafter, the first locating element  16  fixed to the first attachment device  19   a  arrives at the pulley  8  of the first flexible band  7  and begins rotating about the circumference, displaced also by the articulated mechanism  24 , and is distanced from the bottles P (see FIG.  9 ). The bottles P of the selected group thus no longer slip on the belt  3  but advance now at the same speed V as the belt and are distanced from the bottles P of the column next in sequence, still retained by the second locating element  17 , advancing thence toward the downstream stations. 
     At the same time, the locating element  16  fixed to the fourth attachment device  19   d  of the first flexible band  7  is accelerated and will rotate about the pulley  8  to locate between the bottles P, a component of its speed V 1  measured along the conveying direction C of the belt  3  substantially matching the speed V 2  of the locating element  17  associated with the second flexible band  9 . 
     Another group of bottles P will now have been formed between the two locating elements  16  and  17 , and this too is distanced in the manner described above. 
     Thus, each successive group of bottles P is held by a locating element  16  associated with the first flexible band  7  and at the same time by a locating element  17  associated with the second flexible band  9 . The two flexible bands  7  and  9  are accelerated in alternation, through the agency of the control means  29 , in such a way as to distance the selected groups one from the next and allow the location of the rods  18  between the bottles P at the correct speed. 
     The stated objects are duly realized in a device thus described, thanks to the simple and flexible structure adopted. 
     In particular, a device according to the present invention for separating continuously fed products into groups is able to separate products of varying dimensions, for example cans or large bottles, into groups of predetermined pack size 
     Moreover, the device according to the invention will allow of identifying the number of products making up each group. 
     Finally the device according to the invention will prompt the correct configuration for the job automatically, on the basis of the range of values compassing the dimensions of the selected products and the number of products that must make up each group, guaranteeing a better man-machine interface and considerable ease of use.