Patent Publication Number: US-9850012-B2

Title: Product stacking device

Description:
BACKGROUND OF THE INVENTION 
     Product stacking devices for forming product stacks of product groups consisting of products which lie flatly and/or are brought into a shingled product arrangement during a transportation movement are already known. The product stacking devices comprise at least two stop means with stack contact surfaces which are provided in order to form the product stack. 
     SUMMARY OF THE INVENTION 
     The invention relates to a product stacking device for forming product stacks of product groups consisting of products which lie flatly and/or are brought into a shingled product arrangement during a transportation movement. The product stacking device comprises at least two stop means with stack contact surfaces which are provided in order to form the product stack. 
     A merging unit is provided for forming at least one product stack by reducing a spacing between stack contact surfaces of at least two stop means, said stack contact surfaces lying opposite one another in a product group direction. A disk-shaped foodstuff, in particular a biscuit, is preferably to be understood in this context by the term “product”. Other stackable products are however also conceivable. The product stacks are preferably provided for packaging on a packaging machine, in particular a horizontal tube packaging machine known to the person skilled in the art and/or a roll packaging machine and/or a cartoning machine. A product arrangement which “lies flatly” refers in this context particularly to an arrangement in which products are carried while arranged side by side and lying flat by a product support, such as a conveyor belt and/or a conveying surface. A “stop means” is particularly to be understood in this context as a means which is provided to transfer at least a force and/or position to a product or a product group by means of mechanical contact. 
     A “shingled product arrangement” refers in this context particularly to a product arrangement in which, with the exception of a last product, products bear respectively in a shingle direction with one side on a proximate adjacent product, wherein a succeeding product in turn bears on an opposite side of the product in a direction opposite to the shingle direction. In the shingled product arrangement, the last product in the shingle direction can bear on a product support and/or a stack contact surface. The term “shingle direction” is to be understood in this context preferably as a direction parallel to the direction of transportation in which the products are inclined starting from a line perpendicular to the direction of transportation. The shingle direction is preferably identical to the direction of transportation. In a further embodiment of the invention, it is also possible for the shingle direction to be disposed at an angle, in particular a right angle, to the direction of transportation. In a shingled product arrangement, primary surfaces of adjacent products can particularly overlap by more than 10%, preferably by more than 30% and especially preferably by more than 50%. Primary surfaces of adjacent products in the shingled arrangement preferably overlap by less than 90%, especially preferably by less than 80%. The two largest surfaces of a product are particularly to be understood in this context as “primary surfaces”. A shingle angle, which the primary surfaces of the products form with the product support in the shingled product arrangement, amounts to 15°-60°, particularly preferably 25°-35°. All products of a product group assume a shingled product arrangement. A product which is last in the shingle direction can alternatively lie flatly on the product support and the further products can be present in a shingled product arrangement, wherein the last shingled product in the direction of the shingle direction rests on the flatly lying last product. If the products in this alternative arrangement are inclined in the direction of transportation, the product last in the direction of transportation preferably lies flatly on the product support. If the products are inclined oppositely to the direction of transportation, the product which is first in the direction of transportation preferably lies flatly on the product support. This arrangement can be particularly suited to forming a vertical product stack. Shingled product arrangements are known to the person skilled in the art. A “product stack” is particularly to be understood in this context as a product arrangement in which primary surfaces of the products enclose an angle of at least substantially 0° or 90° with a horizontal product support and/or a horizontal. A “horizontal” is particularly to be understood in this context as a direction perpendicular to a weight force and/or the direction of conveyance. A horizontal product stack results at an angle of substantially 0° and a vertical product stack at an angle of substantially 90°. The term “at least substantially” is to be understood in this context as a deviation of less than 15°, preferably less than 10°, and especially preferably less than 5°. Products of a product stack preferably have an overlap of more than 80%, especially preferably of more than 90%. A transition from a shingled product arrangement to a product stack preferably can take place continuously. The product stacking device is preferably provided to transfer products supplied lying flat into a shingled product arrangement prior to stacking. A “transportation movement” refers in this context particularly to a movement in a direction of conveyance. The transportation movement is preferably provided to transport the products to a further manufacturing process, in particular to a packaging process. The direction of conveyance can change the direction thereof at least along sub-regions of a transport route, in particular continuously. The transportation movement is preferably continuous at least in one operating state. The term “continuous” is particularly to be understood in this context as without stoppages. Changes in speed of the transportation movement are preferably constant. A “stack contact surface” is to be particularly understood in this context as an area of a stop means, whereat at least one product of a product group and/or a product stack touches the stop means. The stack contact surface can be approximately linear and/or punctiform. A “merging unit” is particularly to be understood in this context as a unit which is provided to reduce the distance between stack contact surfaces in the product group direction. The merging unit can particularly comprise a plurality of mechanical and/or electronic control units, one or a plurality of bearing units or one or a plurality of fastening units. The merging unit can particularly contain mechanical linkages and/or link controls and/or angular faces. Mechanical linkages, link controls and/or angular faces can particularly be provided to control, contingent on a position and/or a movement, at least one further position and/or movement, such as, in particular, a translation and/or a rotation of at least one stop means. Such devices are known to the person skilled in the art. A “product group direction” refers particularly in this context to a mean direction, along which the supplied products of a product group are disposed adjacent to one another or in a shingled manner. A “spacing” between the stack contact surfaces in the product group direction is particularly to be understood in this context as a mean distance, which is measured in the product group direction, between areas of the stack contact surfaces lying opposite one another which are touched by products of a product group during stacking at the point in time of determining the spacing. The product stack can be effectively formed by pushing together a supplied product arrangement. A continuous stacking can be especially simple. The transportation movement can be without interruption. The product stacking device can thus operate highly efficiently. Many product stacks can particularly be formed per each time unit. The product stacks can be transported very easily in the direction of the further manufacturing process. 
     The invention furthermore proposes that at least one stop means is formed by a driver and/or a counter holder of a delivery device. A “delivery device” is particularly to be understood in this context as a device which is provided to supply products and/or product stacks to a packaging process of a packaging machine. The delivery device can particularly take on products lying flat or shingled in a product arrangement and transfer the same as a product stack to the packaging machine at the end of the transport route. A “driver” refers in this context particularly to an element which is provided to push and/or carry at least one product or a product group in the direction of transportation by means of a frictional connection or a positive locking connection. A “counter holder” is particularly to be understood in this context as an element which is provided to support at least one product or a product group against the direction of transportation by means of a frictional connection and/or preferably a positive locking connection. The counter holder can particularly be provided to prevent a tipping of products. The drivers and/or counter holders can transport the products and form the product stacks. Components can thus be saved. The delivery device can comprise the product stacking device. A particularly cost effective and compact design can be made possible. The delivery device can particularly contain a conveying system circulating around a preferably closed path, such as a chain and/or a guide channel designed as a closed loop. The transport route can particularly be part of the path of the conveyance system. Drivers and/or counter holders can preferably be movably mounted on the conveyance system in the direction of conveyance at least in the area of the transport route. A drive system, in particular the chain, can be provided to drive the drivers and/or counter holders along the path. In a particularly preferred manner, the drivers and/or counter holders can be individually driven at least in sub-regions of the conveyance path, in particular by means of a linear motor system. The conveyance system can preferably have at least one primary part of a linear motor system. The drivers and/or counter holders can preferably be disposed on conveying elements which comprise secondary parts of the linear motor system, in particular permanent magnets. Drivers and counter holders can be moved in a particularly flexible manner. Distances between driver and counter holder can, in particular, vary. Spacings between the stop means can be flexibly adapted. Product stack lengths and/or product group lengths can be easily adapted. Product stacks having in each case a different length and/or in each case a different number of products can be formed. 
     At least one bearing unit is furthermore proposed, by means of which at least one of the stop means can be rotatably mounted about at least one degree of freedom. The bearing unit can particularly be part of the merging unit. The spacing between stack contact surfaces of two stop means, which contact surfaces lie opposite one another, can be effectively reduced by rotating at least one of the stop means. The stop means can preferably be rotatably mounted about an axis which is at least substantially transverse, i.e. at an angle of 90° relative to the product group direction. The phrase “at least substantially” is to be understood in this context as a deviation of less than 30°, preferably less than 10° and especially preferably less than 5°. The bearing unit can rotatably mount the stop means to conveying means, such as a chain, and/or to conveying elements of the delivery device. The spacing between stack contact surfaces lying opposite one another in a product group direction, between a stop means disposed on the delivery device and designed, in particular, as a driver and rotatably mounted stop means, can be effectively reduced. A rotatably mounted stop means can effectively influence a shingle angle of the shingled product arrangement and convert said shingle angle into an angle of a product stack. At least two stop means, in particular a driver and a counter holder, which are provided to form a product stack can advantageously be rotatably mounted on bearing units. A shingle angle and a spacing between stack contact surfaces can effectively be set. A product stacking can be especially gentle on the product. It is possible in a further embodiment of the invention for further stop means to be rotatably mounted on at least one bearing unit. The further bearing unit can preferably be disposed on a side of the product groups which lies opposite the delivery device in the direction opposite to a weight force. Further possible arrangements of a mounting of the further stop means are also conceivable. The further stop means can effectively support a product stacking. Counter holders of a delivery device that are moved along the delivery direction can be omitted. 
     At least one bearing unit is further proposed, via which at least one of the stop means is translationally movably mounted in at least one degree of freedom at least along a working section. The bearing unit can particularly be part of the merging unit. The spacing between stack contact surfaces of two stop means, said stack contact surfaces lying opposite one another, can be effectively reduced by a translational movement of at least one stop means at least substantially in the product group direction. 
     At least one drive unit is further proposed with which the at least one stop means can be driven in at least one degree of freedom. 
     The drive unit can particularly have an actuator like a rotary cylinder, a stepper motor and/or in particular a servo drive and/or comprise a link control. A control unit of the merging unit can be provided to open-loop and/or close-loop control a movement of the stop means in the degree of freedom. The degree of freedom can particularly be a rotation or a translation. The control unit can effectively set the spacing between stack contact surfaces of two stop means, said stack contact surfaces lying opposite one another. 
     The invention further proposes that the merging unit is provided to form the at least one product stack by actuating the at least one drive unit. The merging unit can particularly reduce the spacing between stack contact surfaces lying opposite one another in the product group direction; thus enabling a product group to be pushed together to a product stack. If a desired stack length is achieved, the merging unit can at least substantially keep the spacing constant between stack contact surfaces lying opposite one another in the product group direction. Force measuring devices can preferably be provided which signal an increase in a force between the stop means, said force being caused by the product stack, if the product stack length is achieved and/or undershot. The force measuring devices can be provided on the stop means and/or on the bearing means of the stop means. Drive variables of the drive units of the stop means can preferably be used to determine a force, in particular drive currents and/or torques and/or forces. A particularly gentle and flexible stacking can then be made possible. 
     The invention further proposes that at least one stop means has stack contact surfaces on two sides lying opposite one another in the product group direction. Product stacks can particularly be formed in each case between stop means disposed successively in the product group direction. A stop means can simultaneously form a stack contact surface of a product stack and a further stack contact surface of a product stack that is adjacent in the product group direction. The number of the stop means can be reduced. The product stack device can be particularly compact and cost-effective. 
     It is furthermore proposed that the merging unit comprises at least one link control. The link control can have, in particular, a connecting link that is fixedly mounted to the product stack device and/or to the delivery device. The link control can particularly be provided to displace and/or pivot the stop means on the basis of position. The stacking can take place in a mechanically controlled manner, in particular on the basis of a position of the product group and/or the stop means along the transport route. Additional controlled drives, in particular servo- and/or linear motors for controlling the stacking can be omitted. The product stacking device can thus be particularly cost effective. 
     The invention further proposes that the merging unit comprises at least one electrical and/or electronic control unit. The control unit can preferably be provided for individually closed-loop or open-loop controlling spacings between stack contact surfaces of stop means, said stack contact surfaces lying opposite one another in a product group direction. The stacking can be especially flexible. Different stack lengths can be possible. In particular, a mechanical changeover and/or a modification to the product stacking device for forming product stack of different lengths can be avoided. 
     According to an alternative embodiment of the invention, the merging unit comprises at least one stop means that is formed from a lateral guide which is angled with respect to the transportation movement. The merging unit preferably comprises at least two stop means which lie opposite one another in a product group direction and are formed from angled lateral guides. The stop means are preferably angled in such a manner that the spacing between stack contact surfaces lying opposite one another in the product group direction decreases in the direction of the transportation movement. The transportation movement is preferably at least substantially transverse to the product group direction. The stacking preferably takes place at least substantially by means of a reduction in the product group length transversely to the direction of transportation. The term “at least substantially” is to be particularly understood in this context as a deviation by less than 30°, preferably by less than 15°, and especially preferably by less than 5°. 
     The product groups are preferably led past the stack contact surfaces by means of the transportation movement in such a way that said product groups are pushed together due to the spacing thereof being reduced in the direction of transportation. The spacing of the lateral guides with respect to one another and the angle of the angled position with respect to the product group direction and/or the transportation movement can preferably be adjusted with the aid of a suitable, adjustable bearing device of the lateral guides. The stacking can take place by means of a static arrangement of elements of the merging unit. The merging unit can be especially simple in design. An open-loop or closed-loop control of movements and/or drives for the purpose of stacking can be omitted. A large number of product stacks can successively be formed in a continuous manner between the stop means. The product adapter unit can be especially efficient. The lateral guides can be designed as fences. The lateral guides preferably comprise circulating belts and/or bands. Friction between product groups and lateral guides can be minimized. The product stacks can be formed in a very protective manner. 
     According to one variant of the invention, at least one of the stop means is provided to space the product groups of the delivered products apart from one another. In particular, the stop means can be guided between two successive product groups of the products delivered lying flat and/or in a shingled product arrangement. The product groups can be separated by the stop means and be spaced apart from one another by said stop means. The product group is formed from a number of products which are to form a product stack. The product groups of the products delivered lying flat or in a shingled product arrangement can be delivered to the product stacking machine without the product groups already being spaced apart from one another. A separate device provided to space apart product groups is thus rendered unnecessary. The product groups can preferably be spaced apart from one another by drivers of the product stacking device. The drivers can advantageously be guided between product groups, space apart said product groups from one another and thereby form product stacks by said drivers pushing the product groups during the transportation movement against respectively one counter holder. Thus, the product stacking device can very efficiently space product groups apart from one another and form product stacks. 
     According to a further variant of the invention, an input belt is provided, at least in a first step of forming the product stack, to push the product groups lying on the input belt with the transportation movement against slower moving stop means moving opposite to the transportation movement. The products delivered lying flat and/or in a shingled product arrangement are preferably placed onto the input belt and/or are transported by the input belt during the transportation movement. The input belt preferably has a gap, through which the stop means protrudes. The input belt can particularly be formed by two parallel belts, between which a gap is formed through which the stop means protrudes. The products can preferably be individually dispensed onto the input belt from a feed belt. The stop means can be designed as a counter holder and is moved slower with respect to the transportation movement of the input belt. The products are pushed by the input belt against the counter holder and form a shingled product arrangement. Due to the faster movement of the input belt in comparison to the counter holder, the shingle angle of the product arrangement can become increasingly steeper during the transport. The second stop means is advantageously designed as a driver and forms a product stack in a second step by reducing the spacing between the stack contact surfaces of the stop means, said stack contact surfaces lying opposite one another in the product group direction. The input belt can advantageously support the product stacking. The first step of the product stacking by means of the input belt can particularly be performed in a product protective manner. Damage to the products can thus be prevented. 
     According to the invention, a method for forming at least one horizontal or vertical product stack using a previously described product stacking device is proposed. Two stop means can quickly and effectively push shingled product groups together to form a product stack by reducing the spacing between stack contact surfaces lying opposite one another in the product group direction. In order to form a vertical product stack, a first or last product of the product group can particularly be disposed in a product configuration that lies flat. Further products can be disposed in a shingled product configuration, wherein the product adjacent to the product that lies flatly rests on the same. When the spacing between the stack contact surfaces is reduced, the products can be pushed together to form a vertical product stack. In order to form a horizontal product stack, all of the products of a product group can especially be disposed in a shingled product arrangement. By reducing the spacing between the stack contact surfaces, the shingle angle can be enlarged until the shingled product arrangement passes into a horizontal product stack. A fast and simple stacking can thereby be implemented. The stacking can take place in a continuous movement, in particular conjointly with a transportation movement. 
     According to the invention, provision is furthermore made for a delivery device, in particular for delivering products to a packaging process, comprising a product stacking device. The product stacking device can particularly be integrated into the delivery device. Conveying elements of the delivery device can form stop means of the product stacking device. Components can thus be saved. A particularly compact design of the delivery device comprising the product stacking device can thus be made possible. In a particularly preferred manner, the delivery device can be part of a packaging machine. The packaging machine can have the aforementioned advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages ensue from the following description of the drawings. Exemplary embodiments of the invention are depicted in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently consider the features in isolation and put them together to form further useful combinations. 
       In the Drawings: 
         FIG. 1  shows a schematic depiction of a delivery device comprising a product stacking device in a first exemplary embodiment; 
         FIG. 2  shows a schematic depiction of a delivery device comprising a product stacking device in a second exemplary embodiment; 
         FIG. 3  shows a schematic depiction of a delivery device comprising a product stacking device in a third exemplary embodiment; 
         FIG. 4  shows a schematic depiction of a section of a delivery device comprising a product stacking device in a fourth exemplary embodiment; 
         FIG. 5  shows a schematic depiction of a delivery device comprising a product stacking device in a fifth exemplary embodiment; 
         FIG. 6  shows a schematic depiction of a delivery device comprising a product stacking device in a sixth exemplary embodiment; 
         FIG. 7  shows a schematic depiction of a delivery device comprising a product stacking device in a seventh exemplary embodiment; 
         FIG. 8  shows a schematic depiction of a delivery device comprising a product stacking device in an eighth exemplary embodiment, 
         FIG. 9  shows a schematic depiction of a delivery device comprising a product stacking device in a ninth exemplary embodiment; 
         FIG. 10  shows a schematic depiction of a packaging machine comprising the product stacking device of the first exemplary embodiment; 
         FIG. 11  shows a schematic depiction of a delivery device comprising a product stacking device in a tenth exemplary embodiment; and 
         FIG. 12  shows a schematic depiction of a delivery device comprising a product stacking device in an eleventh exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a product stacking device  10   a  for forming product stacks  12   a  of product groups  14   a  consisting of products  16   a  delivered lying flat during a transportation movement  28   a , said stacking device comprising stop means  18   a  with stack contact surfaces  20   a  which are provided in order to form the product stack  12   a . The product stacking device  10   a  has a merging unit  22   a  which is provided for forming the product stack  12   a  by reducing a spacing  24   a  between stack contact surfaces  20   a  of two stop means  18   a , said stock contact surfaces lying opposite one another in the product group direction  26   a . The product stacking device  10   a  is part of a delivery device  34   a  of a packaging machine  110   a  ( FIG. 10 ). In the example shown, a web of products  16   a  is delivered to the product stacking device  10   a . In an extension of the exemplary embodiment depicted here, a multi-web embodiment is also possible in which a plurality of webs of products  16   a  is supplied in parallel in order to form a plurality of product stacks  12   a  in juxtaposition. As a result, the stop means  18   a  can simultaneously form a plurality of product stacks  12   a  disposed adjacent to one another, or a plurality of stop means  18   a  can be provided side by side. 
     The products  16   a  are placed via a feed belt  58   a  in a delivery direction  60   a  onto an input belt  62   a  so as to lie flatly. In so doing, product groups  14   a  are formed in a shingled product arrangement  64   a . The stop means  18   a  are formed by drivers  30   a  and counter holders  32   a  of the delivery device  34   a . The drivers  30   a  and the counter holders  32   a  are mounted on a circulating chain  66   a  and are moved along a transport route  68   a  in the direction of conveyance  70   a . The feed belt  58   a  can be designed as a so-called “pullnose” belt in which a belt end  72   a  is movable in the delivery direction  60   a  in order to facilitate a formation of gaps between the product groups  14   a . Different solutions are known here to the person skilled in the art. 
     The drivers  30   a  are provided to push the product groups  14   a  resting on the product support  74   a  in the direction of conveyance  70   a  towards a packaging machine at the end of the transport route  68   a , said packaging machine not being depicted in detail here. The drivers  30   a  are retractably mounted on the chain  66   a  in a direction perpendicular to the direction of conveyance  70   a ; thus enabling said drivers to be lowered by means of a link control, which is not depicted here in detail, under the product support  74   a  in the area of the feed belt  58   a  as a result of a pivoting movement. After a product group  14   a  has been formed with a desired number of products  16   a , the driver  30   a  is raised, so that said driver can transport the product group  14   a , which is supported on the product support  74   a  on the basis of a weight force  76   a , by means of a positive locking connection. The product group  14   a  has initially the shingled product arrangement  64   a  in the product group direction  26   a , which is parallel to the direction of conveyance  70   a , at a shingle angle  78   a  between primary surfaces  106   a  of the products  16   a  and the product support  74   a  of less than 45°. The counter holders  32   a  are provided to support the product groups  14   a  resting on the product support  74   a  against the direction of conveyance  70   a . Drivers  30   a  and counter holders  32   a  form stop means  18   a  of the product stacking device  10   a  and touch the product groups  14   a  with stack contact surfaces  20   a.    
     Bearing units  36   a  mount the stop means  18   a  designed as counter holders  32   a  on the chain  66   a  so as to be rotatable about one degree of freedom  38   a . The product support  74   a  comprises a bearing unit  40   a  which mounts the stop means  18   a  in a translationally movable manner along a working section  42   a  that corresponds to the transport route  68   a  in one degree of freedom  44   a  along the direction of conveyance  70   a . A drive unit  46   a  drives the chain  66   a . The stop means  18   a  designed as drivers  30   a  are driven by the chain  66   a  in the translational degree of freedom in the direction of conveyance. Due to the movement of the drive unit  46   a , a link control  52   a  moves the stop means  18   a  designed as counter holders  32   a  in the degree of freedom  38   a  in a pivoting movement  80   a.    
     The stop means  18   a  with the link control  52   a  and the bearing units  36   a  and  40   a  are part of the merging unit  22   a . The pivoting movement  80   a  causes a reduction in the spacing between the stack contact surfaces  20   a  of the driver  30   a  and the counter holder  32   a , said stack contact surfaces lying opposite one another in the product group direction  26   a . The product groups  14   a  are, starting from the shingled product arrangement  64   a , raised to a horizontal product stack  12   a . Drivers  30   a  and counter holders  32   a  are now moved synchronously in the direction of conveyance  70   a  and transfer the product stacks  12   a  to a packaging process of the packaging machine at the end of the transport route  68   a . In a variant which is not depicted here in detail, the counter holders  32 , relative to the chain  66   a , are additionally movably mounted translationally in the direction of conveyance  70   a  against a spring force or by means of a drive that can be controlled in an open-loop or closed-loop system. A product stack length  90   a  can thus be additionally adapted. 
     The following description and the drawings of further exemplary embodiments are substantially limited to the differences between the exemplary embodiments, wherein, with regard to identically denoted components, in particular to components having the same reference signs, reference can basically be made to drawings and/or the description of the other exemplary embodiments. In order to differentiate the exemplary embodiments, the letters b to k are placed behind the reference numerals in the further exemplary embodiments instead of the letter “a” of the first exemplary embodiment. 
       FIG. 2  shows a product stacking device  10   b  for forming product stacks  12   b  of product groups  14   b  consisting of products  16   b  delivered lying flat during a transportation movement  28   b , comprising stop means  18   b  with stack contact surfaces  20   b  which are provided for forming the product stack  12   b  in a second exemplary embodiment. 
     The product stacking device  10   b  differs from the first exemplary embodiment particularly by virtue of the fact that the stop means  18   b  designed as drivers  30   b  and counter holders  32   b  of a delivery device  34   b  are disposed on conveying elements  82   b  which can be individually driven in a position-controlled and speed-controlled manner by means of a drive unit  46   b  formed from a linear motor system  84   b . The conveying elements  82   b  each comprise a secondary part  86   b  of the linear motor system  84   b . Instead of a chain, the delivery device  34   b  contains a primary part  88   b  disposed along a circumferential path and comprising electromagnets that can be individually actuated. An electronic control unit  54   b  individually controls position and speed of the conveying elements  82   b . The control unit  54   b  forms with the linear motor system  84   b  and the conveying elements  82   b  comprising the stop means  18   b  a merging unit  22   b . The control unit  54   b  controls position and speed of the stop means  18   b  during the transportation movement  28   b  to a packaging process in such a way that a spacing  24   b  between stack contact surfaces  20   b  of at least two stop means  18   b  is reduced, said stack contact surfaces lying opposite one another in a product group direction  26   b . In so doing, the counter holders  32   b  are mounted on the conveying elements  82   b  by means of bearing units  36   b  so as to be rotatable about one degree of freedom. A pivoting movement  80   b  is controlled by a link control  52   b  independently of a position along a transport route  68   b . The spacing  24   b  is determined by a superimposition of the pivoting movement  80   b  as well as by the relative positions of the stop means  18   b  with respect to each other which are controlled by the control unit  54   b . Starting from a shingled product arrangement  64   b , the product group  14   b  can be raised to a horizontal product stack  12   b  by combining the pivoting movement  80   b  with a translation of the stop means  18   b  in the direction of conveyance  70   b . Different product stack lengths  90   b  can be set by the control unit  54   b  without a mechanical format changeover or a modification of the product stack device  10   b . It is also possible that product stacks  12   b  that are successive in the direction of conveyance  70   b  have different product stack lengths  90   b.    
     In a third exemplary embodiment,  FIG. 3  shows a product stacking device  10   c  for forming product stacks  12   c  of product groups  14   c  consisting of products  16   c  delivered lying flat during a transportation movement  28   c , comprising stop means  18   c  with stack contact surfaces  20   c  which are provided for forming the product stacks  12   c . The product stacking device  10   c  differs from the product stacking device  10   a  of the first exemplary embodiment particularly by virtue of the fact that drivers  30   c  and counter holders  32   c  of a delivery device  34   c  are rotatably mounted on bearing units  36   c  in one degree of freedom  38   c  on a chain  66   c . A movement about the degree of freedom  38   c  of the drivers  30   c  and the counter holders  32   c  is controlled via a link control  52   c . Drivers  30   c , counter holders  32   c  and link control  52   c  are part of a merging unit  22   c . A shingle angle  78   c  of the product groups  14   c  is influenced by the counter holders  32   c . The counter holders  32   c  tilt up with respect to a weight force  76   c  along a transport route  68   c  during product stacking; thus enabling the shingle angle to increase. The drivers  30   c  are likewise raised along the transport route  68   c  until drivers  30   c  and counter holders  32   c  are perpendicular to a direction of conveyance  70   c . A spacing  24   c  between stack contact surfaces  20   c  of the stop means  18   c  designed as drivers  30   c  and counter holders  32   c , said stack contact surfaces lying opposite one another in a product group direction  26   c , is reduced such that horizontal product stacks  12   c  are formed. The product stacks  12   c  are formed in a particularly product protective manner as a result of the drivers  30   c  and counter holders  32   c  being simultaneously raised. 
     In a fourth exemplary embodiment,  FIG. 4  shows a product stacking device  10   d  for forming product stacks  12   d  of product groups  14   d  consisting of products  16   d  delivered in a shingled product arrangement  64   d  during a transportation movement  28   d , comprising stop means  18   d  with stack contact surfaces  20   d  which are provided for forming the product stacks. 
     The product stacking device  10   d  differs from the second exemplary embodiment particularly in that the stop means  18   d  designed as drivers  30   d  and counter holders  32   d  are moved in a translation superimposed on the transportation movement  28   d  in and/or opposite to a direction of conveyance  70   d  for the purpose of reducing a spacing  24   d  between stack contact surfaces  20   d  which lie opposite one another in a product group direction  26   d . Drivers  30   d  and counter holders  32   d  are part of a merging unit  22   d . A bearing unit, which facilitates a pivoting movement, can be omitted. The design is particularly simple and cost effective. 
     In a fifth exemplary embodiment,  FIG. 5  shows a product stacking device  10   e  for forming product stacks  12   e  of product groups  14   e  consisting of products  16   e  delivered lying flat during a transportation movement  28   e , comprising stop means  18   e  with stack contact surfaces  20   e  which are provided for forming the product stacks  12   e.    
     The product stacking device  10   e  differs from the second exemplary embodiment particularly by the fact that the stop means  18   e  have stack contact surfaces  20   e  on two sides lying opposite one another in a product group direction  26   e . The product stacking device  10   e  is provided for forming vertical product stacks  12   e . A stop means  18   e  simultaneously assumes the function of a driver  30   e  of a product group  14   e  and a counter holder  32   e  of a succeeding product group  14   e  moving against a direction of conveyance  70   e . The number of stop means  18   e  is reduced in relation to the preceding exemplary embodiments. 
     Prior to stacking, the product  102   e  of the delivered product group  14   e  which is last in the direction of conveyance  70   e  lies flatly in each case on an input belt  62   e , while further products  104   e  of the product group  14   e  are disposed in a shingled product arrangement  64   e . The shingled further products  104   e  are directly or indirectly supported on the last product  102   e . If a spacing  24   e  between stack contact surfaces  20   e  lying opposite one another in the product group direction  26   e  is reduced, the further products  104   e  are pushed onto the last product  102   e ; thus enabling a vertical product stack  12   e  to form. The stop means  18   e  driven by a drive unit  46   e  together with a control unit  54   e  provided for controlling the position and speed of the stop means  18   e  belong to a merging unit  22   e . The drive unit  46   e  is designed as a linear motor system  84   e  as in the second exemplary embodiment and is provided to individually drive the stop means  18   e.    
     In a sixth exemplary embodiment,  FIG. 6  shows a product stacking device  10   f  for forming product stacks  12   f  of product groups  14   f  consisting of products  16   f  delivered lying flat during a transportation movement  28   f , comprising stop means  18   f  with stack contact surfaces  20   f  that are provided for forming the product stacks  12   f.    
     The product stacking device  10   f  differs from the fifth exemplary embodiment in particular in that the stop means  18   f  on bearing units  36   f  are rotatably mounted on conveying elements  82   f . The forming of product stacks  12   f  is supported by an additional pivot movement  80   f  and takes place in a very product protective manner. The pivoting movement  80   f  is controlled by a link control  52   f  as a function of a position of the stop means  18   f  along a transport route  68   f . A linear motor system  84   f  serves to provide an independent open-loop and closed-loop control of speed and position of the stop means  18   f  by means of a control unit  54   f . The stop means  18   f , the link control  52   f , the bearing units  36   f  and a drive unit  46   f  designed as a linear motor system  84   f  are parts of a merging unit  22   f . At the end of the transport route  68   f , the product stacks  12   f  are encased in a film tube  108   f  during a packaging process of a packaging machine  110   f . Individual packages comprising respectively one product stack  12   f  are formed from the film tube  108   f  by a sealing unit which is not depicted here in detail. 
     In a sixth exemplary embodiment,  FIG. 7  shows a product stacking device  10   g  for forming product stacks  12   g  of product groups  14   g  consisting of products  16   g  delivered lying flat during a transportation movement  28   g , comprising stop means  18   g  with stack contact surfaces  20   g  that are provided for forming the product stacks  12   g.    
     The product stack device  10   g  differs from the first exemplary embodiment particularly in that the stop means  18   g  designed as counter holders  32   g  are rotatably mounted about a bearing unit  36   g , wherein the bearing unit  36   g  in the depicted example is disposed opposite to a weight force  76   g  above the product groups  14   g . It is also conceivable in an alternative configuration for at least one bearing unit of stop means to be disposed next to the product groups  14   g  in relation to the transportation movement or below said product groups  14   g  in relation to the weight force  76   g . The stop means  18   g  are disposed on a wheel  92   g  which is mounted on the bearing unit  36   g  so as to be rotatable about a rotational axis  94   g . Stop means  18   g  designed as drivers  30   g  push the product groups  14   g  in a direction of conveyance  70   g  against one of the counter holders  32   g . The counter holder  32   g  is oriented at this point in time in the direction of the weight force  76   g  perpendicularly downward. A spacing  24   g  between stack contact surfaces  20   g  of the counter holders  32   g  and drivers  30   g , said stack contact surfaces lying opposite one another in the product group direction  26   g , is reduced so that a product stack  12   g  is formed from the product group  14   g . The counter holder  32   g  is subsequently moved away from the product stack  12   g  by means of a pivoting movement  80   g  about the bearing unit  36   g ; thus enabling the driver  30   g  to further transport the product stack  12   g  underneath the counter holder  32   g  in the direction of conveyance  70   g . A next counter holder  32   g  for forming a next product stack  12   g  is subsequently oriented downwards. In the example shown, four counter holders  32   g  are disposed on the wheel  92   g , wherein respectively two counter holders  32   g  lying opposite one another are jointly driven. Successive counter holders  32   g  around the wheel  92   g  can be independently driven; thus enabling the counter holders  32   g  of two successive product groups  14   g  to be synchronized with said product groups  14   g  independently of one another. The movements of the drivers  30   g  and the counter holders  32   g  which are driven by a circulating chain are synchronized by a control unit  54   g . The stop means  18   g  and the control unit  54   g  are part of a merging unit  22   g.    
     In an eighth exemplary embodiment,  FIG. 8  shows a product stacking device  10   h  for forming product stacks  12   h  of product groups  14   h  consisting of products  16   h  delivered lying flat during a transportation movement  28   h , comprising stop means  18   h  with stack contact surfaces  20   h  which are provided for forming the product stacks  12   h.    
     The product stacking device  10   h  differs from the first exemplary embodiment particularly in that a shingle angle  78   h  of a shingled product arrangement  64   h  generated from the products  16   h  delivered lying flat is secured by stop wedges  96   h . The stop wedges  96   h  are disposed on a side of the stop means which faces away from a direction of conveyance  70   h , said stop means being configured as drivers  30   h . At one end of the product group  14   h  in the direction of conveyance  70   h , a stop means  18   h  embodied as a support element  98   h  supports the product group  14   h  which initially rests on the stop wedge  96   h  ( FIG. 8 -I). The drivers  30   h  comprising the stop wedges  96   h  and the support element  98   h  are part of a merging unit  22   h . The stop wedge  96   h  is moved away in the direction of conveyance  70   h  jointly with the product stack  12   h  which follows in the direction of conveyance  70   h . The product group  12   h  is moved by the driver  30   h  following the same likewise in the direction of conveyance  70   h  against the support element  98   h , so that a spacing  24   h  between stack contact surfaces  20   h  of the support element  98   h  and the driver  30   h  is reduced and the product group  14   h  is tilted upwards ( FIG. 8-11 ). A counter holder  32   h  pivotably mounted about one degree of freedom  38   h  on a bearing unit  36   h  on a delivery device  34   h  is pivoted against the product group  14   h  and tilts the product stack  12   h  further up by reducing the spacing  24   h  between the stack contact surfaces  20   h  of the counter holder  32   h  and the driver  30   h , said stack contact surfaces lying opposite one another in a product group direction  26   h , until a product stack  12   h  is formed. The support element  98   h  is moved against a weight force  76   h  away from a product support  74   h  upwards and away from the product stack  12   h  ( FIG. 8 -III). The drivers  30   h  and the counter holders  32   h  jointly transport the product stack  12   h  in the direction of a packaging process. 
     In a ninth exemplary embodiment,  FIG. 9  shows a product stack device  10   i  for forming product stacks of product groups  14   i  consisting of products  16   i  delivered in a shingled product arrangement  64   i  during a transportation movement  28   i , comprising stop means  18   i  with stack contact surfaces  20   i  which are provided for forming the product stacks  12   i.    
     A merging unit  22   i  contains two stop means  16   i  designed as lateral guides  56   i  comprising circulating conveyor belts and a delivery device  34   i  comprising a crossbar chain  100   i . The product groups  14   i  are transported on the crossbar chain  100   i  having a product group direction  26   i  that is transverse to a direction of conveyance  70   i . One of the lateral guides  56   i  is mounted on the delivery device  34   i  at such an angle in relation to the transportation movement  28   i  that a spacing  24   i  in the product group direction  26   i  between the stack contact surfaces  20   i  is reduced in the delivery direction  60   i , whereas the other lateral guide  56   i  is mounted on the delivery device  34   i  parallel to the direction of conveyance  70   i . Due to the spacing  24   i  being reduced, the product groups  14   l  are pushed together during transport in the direction of conveyance  70   i  to form a horizontal product stack  12   i.    
     In a tenth exemplary embodiment,  FIG. 11  shows a product stacking device  10   j  for forming product stacks  12   j  of product groups  14   j  consisting of products  16   j  delivered lying flat during a transportation movement  28   j  by means of a merging unit  22   j  comprising stop means  18   j  with stack contact surfaces  20   j  which are provided in order to form the product stacks  12   j  by reducing a spacing  24   j  between stack contact surfaces  20   j  which lie opposite one another in a product group direction. The product stacking device  10   j  differs from the first exemplary embodiment particularly by the fact that stop means  18   j  designed as drivers  30   j  are provided for spacing the product groups  14   j  of the delivered products  16   j  apart from one another. The stop means  18   j  can, for example, be driven by a circulating chain or a linear motor system. The product stacking device  10   j  of this exemplary embodiment is provided to form horizontal product stacks  12   j . It would likewise be possible to use the particular features of this exemplary embodiment for a product stacking device for forming vertical product stacks. The products  16   j  are delivered flat via a feed belt  58   j  in a delivery direction  60   j  onto an input belt  62   j . The feed belt  58   j  is configured as a double belt comprising two parallel belts, which are spaced apart from one another. After a certain number of products  16   j  have accumulated, which are to form a product stack  12   j , one of the drivers  30   j  is guided in each case between two products  16   j  lying on the feed belt  58   j  and thereby separates two successive product groups  14   j . In order to guide the drivers  30   j  between the products  16   j , said drivers are rotatably mounted in one degree of freedom  38   j  by means of bearing units  36   j  and are actuated via a link control  52   j  in such a manner that said drivers in each case tilt up perpendicularly to the transportation movement at a location whereat they are to be guided between the products. As an alternative to the link control  52   j , provision could, for example, also be made for a servomotorical actuation. A formation of gaps between product groups  14   j  using a means configured separately from the merging unit  22   j , such as a pullnose belt as in the first exemplary embodiment, can thus be omitted. A spacing between stack contact surfaces  20   j  of the driver  30   j  and a second stop means  18   j  designed as a counter holder  32   j  is subsequently in each case reduced in order to form the product stack  12   j . In order to achieve this end, the rotatably mounted counter holders  32   j  are pivoted by means of the link control  52   j  in opposition to the transportation movement  28   j  against the drivers  30   j.    
     In an eleventh exemplary embodiment,  FIG. 12  shows a product stacking device for forming product stacks  12   k  of product groups  14   k  consisting of products  16   k  which are delivered lying flat during a transportation movement, comprising a merging unit  22   k  having stop means  18   k  with stack contact surfaces  20   k  which are provided in order to form the product stacks  12   k . The product stacking device  10   k  of this exemplary embodiment is provided for forming horizontal product stacks  12   k . It would also be possible to analogously use the particular features of this exemplary embodiment for a product stacking device for forming vertical product stacks. The product stack device differs from the first exemplary embodiment particularly by virtue of the fact that an input belt  62   k  is provided, in a first step of forming the product stacks, to push the product groups  14   k  lying on the input belt  62   k  with the transportation movement  28   k  against stop means  18   k  which are designed as counter holders  32  and are slower moving in relation to the transportation movement  28   k . The stop means  18   k  can, for example, be driven by a circulating chain or a linear motor system. The products  16   k  are delivered lying flat via a feed belt  58   k  in a delivery direction  60   k  onto the input belt  62   k . The input belt  62   k  is configured as a double belt comprising two parallel belts which are spaced apart from one another; thus enabling the stop means  18   k  to be guided through the input belt  62   k  in the area of the spacing. The stop means  18   k  are designed as drivers  30   k  and counter holders  32   k  which are rotatably mounted about one degree of freedom  38   k  that is perpendicular to the transportation movement  28   k  and are actuated via a link control  52   k . As an alternative to the link control  52   k , provision could, for example, also be made for a servomotorical actuation. In a first step, the counter holders  32   k  are inclined in the direction of the transportation movement  28   k  and move slower in said direction of the transportation movement  28   k  than the input belt  62   k ; thus enabling the products  16   k  of respectively one product group  14   k  delivered from the feed belt  58   k  onto the input belt  62   k  to be pushed against a counter holder  32   k  and to form shingled product arrangements  64   k . A shingle angle  78   k  of the product groups  14   k  becomes increasingly steeper as a result of the difference in speed between the input belt  62   k  and the counter holder  32   k . In a second step II, the holders  32   k  are placed perpendicularly to the transportation movement  28   k , and the drivers are laid at the end of the respective product group  14   k  which is opposite to the transportation movement by means of a tilting operation. In a step III, the drivers  30   k  are arranged perpendicularly to the transportation movement  28   k  and thus the product stacks are formed by reducing a spacing  24   k  between stack contact surfaces  20   k  of the drivers  30   k  and the counter holders  32   k , said stack contact surfaces lying opposite one another in a product group direction  26   k . Drivers  30   k  and counter holders  32   k  now move synchronously in the direction of the transportation movement  28   k  in order to further transport the product stacks  12   k.