Abstract:
A device for grouping or isolating articles which are transported on a conveyor belt in one or more closed rows and are separated from each other individually or in groups for subsequent processing. At least two elements are provided which can be moved back and forth independently of each other and parallel to the direction of transport, and which can be made to engage with or disengage from the articles in a controlled manner.

Description:
FIELD OF THE INVENTION 
     The invention pertains to a device for grouping or isolating articles such as during boxing, wrapping, or other article-handling operations. 
     BACKGROUND OF THE INVENTION 
     Devices of this type are required at the inlet areas of packaging machinery in order to isolate individual articles or groups of articles that approach as a flow of a closely packed rows, and which are subsequently packed into boxes, cartons or shrink wrap foil. In order to achieve this objective different types of construction have been suggested, such as, e.g., grouping devices that are arranged under a conveyor belt that supplies the articles and are equipped with fingers that reach through gaps between the individual conveyor belts that form the conveyor path (EP 0 485 937 B1). In addition to poor accessibility to the grouping mechanism, the necessary gaps between the individual conveyor belts are also a disadvantage, since the stability and smooth flow of the transported articles is impaired, while foreign bodies can fall into the grouping mechanism and cause faults. 
     Moreover, grouping devices that are arranged laterally on conveyor belts and engage the flow of articles are also known, but these are designed in a very space-consuming manner and, disadvantageously, can only be used for a single track flow of articles (EP 0 447 123 B1, EP 0 126 553 B1, EP 0 400 295 A1). 
     A further disadvantage of the known devices resides in the extensive conversion that is required for articles having different formats. 
     The object of this invention is to provide a compact, easily accessible and flexibly applicable device for grouping or isolating articles. 
     As a result of the use of program controlled drives for the grouping device, there is a high level of service convenience along with a conversion time that, simultaneously, is as short as possible to change over to different types of articles. Differing single article lengths or article group lengths can be adjusted in a gapless manner by merely changing the program or modifying the program. 
     If the stopper cams that are required to isolate the groups of articles are integrated into the guide rails, then, according to one advantageous further development of the invention, the adaptation of the grouping device takes place at the same time as the rail adjustment that, in any case, is necessary when a conversion to another articles dimension is required. 
     In the case of a multi-path design, it is also convenient to have good access from above, while no space is required underneath the conveyor for the grouping device. Exemplified embodiments are explained in the following on the basis of the figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Shown are: 
     FIG. 1 A lateral view of a film packaging machine, incorporating the present invention 
     FIG. 2 a top view of the machine according to FIG. 1 in schematic illustration, 
     FIG. 3 a front view of the machine as seen from the X view in FIG.  1 ,. 
     FIG. 4 the lateral view of the grouping station of the machine according to FIG. 1 in an enlarged illustration, 
     FIG. 5 the top view of the grouping station according to FIG. 2 in an enlarged illustration, 
     FIG. 6 an enlarged, detail view from the lateral view of FIG. 4, 
     FIG. 7 a section viewed along the line A—A in FIG. 6, 
     FIG. 8 a top view onto a guide channel of the grouping station according to FIG. 6, in an enlarged illustration, 
     FIG. 9.1 to  9 . 6  the guide channel of the grouping station according to FIG. 8, in various functional settings, 
     FIG. 10 a top view onto a guide channel of an isolation station for containers, 
     FIG. 11.1 to  11 . 6  the guide channel of the isolation station for containers according to FIG. 10 in various to operational settings, 
     FIG. 12 a top view of a second embodiment of the stopper cam with a mechanical control, and 
     FIG. 13.1 to  13 . 5  the stopper cams according to FIG. 12 in different operational settings. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The most important component groups can be seen in the lateral view of the film packaging machine illustrated in FIG.  1 . Arranged underneath on the left hand side there is an article conveyor  2  with a carton staple conveyor  3 , both of which are continually driven in the same direction. The article conveyor leads to a grouping station  1  with guide rails  4  that form the channels for a single track row of articles. Above the guide rails  4  there are two servomotors  5   a ,  5   b  to control the drive of the stopper cams  7   a ,  7   b  of the grouping station and that can become engaged with the articles  6 . Under the guide rails there is a conveyor belt  8  that forms an essentially closed—that is gap-free—conveyor surface, said conveyor belt connecting flush to the articles conveyor  2  and aligned with it. A conveying means  9  that rises obliquely from bottom to top is arranged under this conveyor belt  8  for the purpose of supplying individual, separated carton blanks. As seen in the direction of transport of the conveyor belt  8 , a rod conveyor  10  is arranged following the grouping station  1 , said rod conveyor taking-on article groups  6 ′ that have been isolated from the article flow with a specific intermediate spacing, continually pushing them onto flat, carton blanks (not illustrated) supplied from below while maintaining the spacing. These are then folded during further progression into so called multipacks and enveloped with shrink wrap film in a folding station  11 . The film is guided obliquely from below through a transverse slot in the article group conveyor  14  between the underside of the multipacks and the upper side of the conveyor—in a manner known in and of itself—and then placed around the individual multipacks. A transfer of the enveloped multipacks to a shrink wrap tunnel takes place for the purpose of shrink wrapping. All of the above named component groups of the machine—with the exception of the grouping station—are driven synchronous in speed and position by a common machine drive  50 . 
     As can be seen in FIG. 3, the guide rails  4  are supported suspended on a transversely adjustable cross bar  15  that is positioned with clearance above the conveyor belt  8 . A handle  51  is provided (FIG. 4) for transverse adjustment. In each of the guide rails  4  there are respectively two carriages  16   a ,  16   b  with stop bars  7   a ,  7   b  that are independent of each other and can move in various planes and that can be swiveled in a controlled manner. The mechanical construction of the carriage  16   a ,  16   b  can best be seen from FIG.  7 . As can be seen from this sectioned illustration, the guide rails  4  respectively comprise two plates  4 ′ that are aligned parallel and vertical with spacing from the conveyor belt  8 . At the upper end there is a rail holder  17  between the indicated plates, and below there are two running tracks  18  that are horizontal and extend in parallel and have an essentially U-shaped cross section, whereby the open sides of the running tracks are directed toward each other and the inner surfaces of their leg sections feature profiling. The plates  4  are provide with horizontal slots S in the area between the spaced running tracks. Despite the slots, the stability of the plates is assured by means of the running tracks that are connected to the plates and that simultaneously serve as spacers and stiffening elements, 
     Each of the carriages  16   a ,  16   b , is comprised of a longitudinal base body  19  with three rollers  20  arranged in a row and supported so as to rotate freely, guided in the profiling of the running tracks  18  in a form-locking manner, and at one end bears two stopper cams  7   a , or  7   b  that are supported so as to swivel in opposite directions around vertical support axes  21 . These stopper cams can be controlled by an actuation element  22  (pneumatic cylinder or the like) by means of a bent lever mechanism  23  (FIG. 8) that transitions from the stand-by position into a working position and the reverse. In FIG. 7 the stopper cams  7   b  of both upper carriages  16   b  are in the stand-by position, that is, completely within the guide rails  4 , while the stopper cams  7   a  of the lower carriage  16   a  assume the working position, that is, laterally projecting through the slot S of the plates  4 ′ into the guide channels formed by the guide rials (see also FIG.  5 ). 
     To drive the carriage  16   a ,  16   b  backward and forward in the running tracks  18 , each carriage is provided with its own toothed belt  24   a  or  24   b , the width of which is dimensioned such that it is guided and accommodated between the plates  4 ′ of a guide rail (FIG.  7 ). A toothed belt is respectively guided by a drive wheel  25 , three deflection wheels  26  and a tension roller  27 , which are supported in the guide rail  4 , while their arrangement can best be seen in FIGS. 4 and 6. The ends of the toothed belt are respectively fastened at the front and the rear end of a carriage  16   a ,  16   b . The belts  25   b  of all upper carriages  16   b  are allocated to a first drive shaft  28   b  and those of the lower carriages  16   a  to a second drive shaft  28   a . A drive wheel  25  designed as a cog wheel is respectively allocated to all of the toothed belts on the first or second drive shaft, whereby these cog wheels, together with the guide rails  4 , can be displaced transverse to the conveying direction during a format conversion to a new article diameter, that is, the cog wheels  25  can be axially displaced on their corresponding drive shafts  28   a  or  28   b  and are guided in a form locking manner. 
     Every guide rail  4  thus forms a complete unit, so that additional guide channels can subsequently be formed with little expenditure by adding rails. The already described servo drives  5   a ,  5   b  drive the first or second drive shafts  28   a ,  28   b  by means of an endless, toothed belt  29  and the corresponding cog wheels  30  (see FIG.  4 ). The servo drives  5   a ,  5   b  are controlled by a servo control module of the machine control or a separate servo control  31  that is connected with it, so that a speed and position synchronous drive of the grouping device  1  is possible in the machine with respect to the remaining component groups of the machine in conjunction with an absolute value generator  32 . In order to be able to undertake as smooth a conversion as possible to differing articles or container sizes or group lengths within the shortest time, the control  31  can be equipped with a selectable program memory for the various types of articles . The control, however, can also be adjusted for an input of desired groups or container lengths that is to be undertaken manually. 
     The manner of operation of the grouping station  1  of the machine illustrated in FIGS. 1 to  8  and previously explained relative to mechanical construction for packaging bottles in multipacks is described in the following in connection with the figure sequence  9 . 1  to  9 . 6  For the sake of simplicity, only a single, respective guide channel of the multi track grouping station is illustrated in the figure sequence in the various stages of a complete grouping cycle. However, as seen together with FIGS. 2 and 5, it is understood that the following, described sequence takes place for a multi track grouping station parallel in all guide channels at the same time or position. The initial setting shown in FIG. 9.1 corresponds exactly to the situation shown enlarged in FIG.  8 . The stopper cams  7   b  of the carriage  16   b  in the right half of the illustration are in the working position, that is, they are spread toward the outside, penetrating the slots S of the guide rail  4  and projecting into the guide channel. Since the carriages  16   b  in this phase are moved at a somewhat slower speed in the direction of operation designated LR than the conveyor belt  8  bearing the bottles  6  by the servo drive  5   b  at a specific synchronous speed ratio, the frontmost bottle  6  of the gapless bottle row abuts the stopper cam  7   b  and is braked slightly by it relative to the conveyor belt  8 , so that a slippage arises between the bottoms of the bottles and the conveyor belt. At the same instant the stopper cams  7   a  of the carriage  16   a  located on the left side of the illustration and also moved by the servo drive  5   a  in the direction of running LR have also spread outward from the stand-by setting, whereby these stopper cams  7   a  now form a stop surface for the upstream bottles. 
     Immediately thereafter, according to FIG. 9.2, the stopper cams  7   b  of the right carriage  16   b  are folded into the guide rails  4 , that is, they are transferred into the stand-by position, whereby the bottle group  6 ′ downstream of the stopper cams  16   a  and including four bottles from now on follows the conveyor belt  8  that abuts the bottles in a friction-locking manner at the unbraked, higher conveyor speed, and thereby an intermediate spacing arises that continually increases with respect to the following row of bottles that are braked by the stopper cams  7   a  and are thus slower. At the same time the servo drive  5   b  is reversed, the carriage  16   b  is accelerated upstream against the running direction LR of the bottles and counter to the direction to the carriage  16   a , while the other two carriages  16   a  as before are congruously moved downstream by its servo drive  5   a . In the counter movement sequence illustrated in FIG. 9.2 to  9 . 5  the upper carriages  16   b  cross over the lower carriages  16   a  and finally reach an upstream position, where the direction of movement of the carriage  16   b  is again reversed by the allocated servo drive  5   b , that is, the carriages  16   b  are again accelerated in the running direction LR and the stopper cams  7   b  are spread outward in the working position between two neighboring bottles, so that a bottle group comprising four individual bottles is again subdivided from the flow of bottles. These stopper cams  7   b  are also again moved at slower speed than the conveyor belt  8  parallel to it. In the meantime, the bottle group  6 ′ that were previously braked by the stopper cam pair  7   b  is distanced so far from the slower, following bottle flow that the separation dimension necessary for the rod conveyor  10  that follows the grouping station  1  has been achieved (FIG.  9 . 6 ). During the entire grouping process there is always at least one stopper cam in the working position, whereby a jolt-free and continually controlled separation of the bottles is assured. 
     A second case of application is shown in FIGS. 10 and 11. The controlled stopper cams  7   a  and  7   b  are used here to isolate containers, e.g. multipacks, cartons or the like. Since these containers feature a square cross-section with planar lateral surfaces and there are no gaps for the engagement of the stopper cams during a blockage as a result of lateral surfaces that contact each other, the upstream stopper cam pair  7   a  is used as a clamping lever to laterally clamp a container  60 , while the downstream stopper cam pair  7   b , as in the previous exemplified embodiment, serves to group the bottles, serving as a stop for the frontmost container  60  of the entering flow of containers (FIG.  10 ). 
     The first illustration of the figure sequence  11 . 1  to  11 . 6  shows the initial position according to FIG. 10, that is the frontmost container  60  of the gapless flow of containers abuts the stopper cam  7   b , while the following container is clamped between the stopper cams  7   a  in a friction locked manner. 
     In this situation both stopper cam pairs  7   a  and  7   b  are moved forward in the conveying direction LR at a slower speed than the conveyor belt that bears the containers in a friction locked manner, so that slippage between this and the containers arises. Thereafter, the stopper cams that are ahead are folded inward into the stand-by position, whereupon the released container is accelerated to the conveyor speed and thereby gains spacing with respect to the following containers. The dimension of the enlargement in spacing is determined by the indicated speed difference of the stopper cam and the conveyor belt and the time span between the release of a container until the release of the following container. 
     According to the illustration in FIG. 11.3, the stopper cam  7   b  that is put out of engagement is guided back upstream against the movement of the containers, while the second stopper cam  7   a  slides unchanged upstream. Then the stopper cams  7   b  are spread into the working position in the gap that in the meantime exists between the two containers and simultaneously the direction of movement of the stopper cam  7   b  is again reversed into the upstream direction, as soon as the front face of the following container comes into contact with the stopper cam  7   b  (FIG. 11.4 and  11 . 5 ). 
     Only then are the stopper cams taken out of engagement, that is folded inward into the stand-by position, driven upstream to the next container, whereupon, following another reversal of the direction of movement into the upstream direction the stopper cams  7   a  are again swiveled into the work position and the containers are thereby clamped laterally (FIG. 11.5 and  11 . 6 ). 
     FIG. 12 shows a purely mechanically acting alternative embodiment to control the working and stand-by positions of the stopper cam. The illustrated stopper cam  7  is swivelably supported at one end on a bolt  34 , said bolt being fastened to the base body  19  of the carriage  16 . A push rod  35  guided in the axial direction on the base body parallel to the running direction LR bears a fork-like designed cam body  36  and a torsion spring  37  that permanently keeps the stopper cam spread outward into the work position. The upstream as well as the downstream end of the push rod  35  project laterally over the base body  19 . 
     Two stops are located on the path of movement of the carriage  16 , whereby at least the upstream stop  38  can be adjusted along the length of the running direction LR. As a result of two parallel legs  40 , the upstream stop  39  has an essentially U-shaped design, whereby the carriage  16  can engage in between the two legs of the stopper cam  7  when the stopper cam  7  is in the stand-by position. 
     The stopper cams  7  in FIG. 13.1 are in the ready position, caused by the fork-shaped cam body  36  that, in part, laterally surrounds the stopper cam and forces it together. As soon as the left, that is, the upstream end of the push rod  35  contacts the stop  39 , the movement of the cam body  36  stops, while the carriage  16  can move farther with the stopper cam  7 , whereby the stopper cams are released from the cam body, but now are prevented from folding out by the legs  40  of the stop  39  (FIG.  3 . 2 ). 
     If the direction of drive of the carriage  16  is now reversed by the allocated servo drive, then the spring loaded stopper cams  7  can spread outward unhindered into the work position after leaving the legs  40  (FIG.  13 . 3 ), until the right, that is the upstream end of the push rod  35  hits the stop  38 , so that the stopper cams  7  slide into the fork-like cam body  36  and thereby are folded inward into the stand-by position (FIG.  13 . 4 ). The direction of movement of the carriage  16  can then again be reversed (FIG.  13 . 5 ), whereby the described sequence starts again from the beginning. By adjusting the stops  38  and/or  39 , the control points of the stopper cams of the respective group or container length can be appropriately adapted. 
     Deviating from the construction illustrated in the figures, the running tracks for the carriage can also be arranged above the articles which are to be grouped. In this case rods that project downward are provided on the carriages guided in the running tracks, said rods bearing the stopper cams at their lower ends, at the height of the article.