Abstract:
The invention relates to a device for conveying strips of corrugated cardboard, the device comprising a work table for conveying strips on the work table along a direction of conveyance, wherein the work table is supported on a floor and comprises at least one longitudinal groove for accommodating an element which is displaceable therein, and at least one slide which is disposed underneath the work table and is actuable for displacement in the direction of conveyance, which slide comprises an element which is actuable for upward extension through the at least one longitudinal groove for cooperation with the strip.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a device and a method of conveying strips of corrugated cardboard. 
       SUMMARY OF THE INVENTION 
       [0003]    It is the object of the invention to provide a device and a method of conveying strips of corrugated cardboard. The object is achieved by a device for conveying strips of corrugated cardboard, the device comprising
   a. a work table for conveying strips on the work table along a direction of conveyance, the work table being supported on a floor;   b. wherein the work table comprises at least one longitudinal groove for accommodating an element which is displaceable therein, and   c. at least one slide which is disposed underneath the work table and is actuable for displacement in the direction of conveyance;   d. which slide comprises an element which is actuable for upward extension through the at least one longitudinal groove for cooperation with the strip.   
 
         [0008]    Furthermore, this object is achieved by a method of conveying strips of corrugated cardboard, the method comprising the following steps:
       providing a device according to the invention;   extending elements in the direction of conveyance so as to be positioned in front a group of strips to be conveyed,   extending elements behind a group of strips to be conveyed,   conveying the group of strips along the direction of conveyance.       
 
         [0013]    The gist of the invention is to provide longitudinal grooves extending along a direction of conveyance in a work table. Underneath the work table are located displaceable slides which are driven individually and comprise pins which are upwardly extendable through the longitudinal grooves. The pins enable the slides to be brought in contact with strips of corrugated cardboard to be displaced such that predefined clusters of corrugated cardboard strips are displaced along the work table in a defined manner. 
         [0014]    Additional features and details of the invention will become apparent from the description of an embodiment by means of the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows a side view of a machine for producing corrugated honeycomb cardboard; 
           [0016]      FIG. 2  shows an enlarged sectional view of the cutting device according to  FIG. 1 ; 
           [0017]      FIG. 3  shows a view according to  FIG. 2  with a single stack of corrugated cardboard strips; 
           [0018]      FIG. 4  shows a plan view of the machine according to  FIG. 1 ; 
           [0019]      FIG. 5  shows an enlarged view of the conveyor device according to  FIG. 1 ; 
           [0020]      FIG. 6  shows an enlarged view of the gluing device according to  FIG. 1 ; 
           [0021]      FIG. 7  shows an enlarged view of the corrugated-cardboard-strip turning device according to  FIG. 1 ; 
           [0022]      FIG. 8  shows an enlarged view of the turning roller according to  FIG. 7 ; 
           [0023]      FIG. 9  shows a view of the corrugated-cardboard-strip turning device according to  FIG. 7 ; and 
           [0024]      FIG. 10  shows a piece of corrugated honeycomb cardboard. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    The following is a description of a machine for producing corrugated honeycomb cardboard  1 . The description starts in the machine according to  FIG. 1  with a block  2  of several single-face webs of corrugated cardboard which are glued together on top of each other. Single-face corrugated cardboard is composed of a web of corrugated cardboard  3  and a smooth liner  4  glued thereto. The production of single-face corrugated cardboard in endless webs is known, for instance from DE 103 12 600 A1. In a corrugated cardboard machine, several layers of single-face corrugated cardboard can be glued together on top of each other, thus resulting in a larger sequence of liners, corrugated webs, liners, corrugated webs, etc. which are glued together. Such multilayer webs of corrugated cardboard are cut into sheets, hereinafter referred to as blocks  2 , which are stacked at the end of the corrugated cardboard machine. These blocks  2  have a block plane  5  as main plane in which is disposed the top  6  of the block  2 . The channels  7  formed between the corrugated web  3  and the liner  4  are parallel to the block plane  5 . The blocks  2  at the beginning of the machine according to  FIG. 1  are aligned such that the channels  7  are parallel to a horizontal direction of conveyance  8  running from right to left in  FIG. 1 . In the machine according to  FIG. 1 , the process starts with a block  2  which is composed of five corrugated webs  3  and liners  4  which are arranged on top of each other in an alternating manner. 
         [0026]    The product created by means of the machine according to  FIG. 1  is referred to as corrugated honeycomb cardboard  1 . An example thereof is shown in  FIG. 10 . The corrugated honeycomb cardboard  1  has a plane top  9  which is disposed in the main plane referred to as corrugated-honeycomb-cardboard plane  10 . The corrugated honeycomb cardboard  1  is substantially characterized in that the channels  7  run crosswise, in particular perpendicular to the plane  10  whereas the channels  7  in the initial block  2  ran parallel to the block plane  5 . The considerable advantage of the corrugated honeycomb cardboard  1  is that it has a high stiffness in several spatial directions. First of all, it is particularly robust against effects of force acting perpendicular to plane  10 . Furthermore, it has a good stiffness when bent about axes which are located in plane  10 . Corrugated honeycomb cardboard  1  within the scope of this application is to be considered a cellular material in the broadest sense in which the channels  7  run crosswise to the main plane  10 . In order to achieve a higher resistance of the corrugated honeycomb cardboard  1  against external influences such as moisture, the corrugated honeycomb cardboard  1  can also be composed of webs  3 ,  4  lined with plastic material and/or wax and/or impregnating agents, or the corrugated honeycomb cardboard  1  can subsequently be coated with plastic material upon production thereof. The webs  3 ,  4  can further consist of paper and/or plastic material and/or webs of material reinforced with fiberglass. Therefore, the term corrugated cardboard or block of corrugated cardboard, respectively, is in the broadest sense to be understood such that the webs of which the corrugated cardboard is made may consist of paper and/or cardboard and/or plastic material and/or webs of material reinforced with fiberglass. Other flexible materials which can be processed accordingly are principally included as well. 
         [0027]    A machine shown in  FIG. 1  for producing corrugated honeycomb cardboard  1  comprises a cutting device  11  which is disposed in a row along the direction of conveyance  8  for cutting strips  12  from a block  2 . Downstream of the cutting device  11  is a conveyor device  13  for conveying the strips  12  along the direction  8  towards a gluing device  14  and then to a corrugated-cardboard-strip turning device  15  disposed downstream thereof. The cutting device  11  comprises a block supplying device  16  comprising a lower endless conveyor belt  17  both ends of which are deflected via two deflection rollers  18 ,  19  in and opposite to the direction  8 , wherein the deflection roller  19  is driven by means of a motor  20  and a drive belt  21 . Above and parallel to the conveyor belt  17  is disposed another conveyor belt  22  which is deflected via deflection rollers  23  and  24 , wherein the deflection roller  24  is driven by a motor  25  by means of a drive belt  26 . The upper conveyor belt  22  is vertically adjustable in height together with the deflection rollers  23  and  24  by means of a height adjustment device  27 , wherein said height adjustment is provided for by means of a spindle drive, for example. The height adjustment device  27  enables the gap  28  formed between the conveyor belts  17  and  22  to be adjusted in height, and thus adapted to the thickness of the block  2 . Instead of conveyor belts  17 ,  22  extending across the entire width of the block  2 , several belts  17 ,  22  distributed uniformly across the width of the block  2  may be used as well, as shown in  FIG. 4 . 
         [0028]    Above the block supplying device  16 , the cutting device  11  comprises a horizontal crossbeam  29  which is supported on a machine frame, extends perpendicular to the direction  8  and is height-adjustable by means of a height adjustment device  30 . A slide  31  is guided on the crossbeam  29  for displacement crosswise to the direction  8 . The crosswise displacement takes place by means of an endless gear belt  32  whose transverse ends are deflected via two rollers  33 ,  34 . The roller  33  is drivable for rotation by means of a motor  35 . The slide  31  is rigidly connected to the upper part  36  of the gear belt  32  such that when the roller  33  is pivoted, this results in a transverse displacement of the slide  31 . The lower part of the slide is provided with a shaft  37  which is mounted thereon for rotation. At the end thereof pointing in direction  8 , the shaft  37  is provided with a roller  38  about which is guided the lower part of the gear belt  32 . At the other end, the shaft is provided with a circular knife  39 . Above the roller  38 , two further deflection rollers (not shown) for the gear belt  32  are mounted on the slide  31 . All rollers  32 ,  34 ,  38  are provided with tooth-shaped recesses which engage with the teeth of the gear belt  32 , enabling a slip-free movement to take place. The circular knife  39 , which is driven for rotation, cuts the block  2  into strips  12 . 
         [0029]    When seen in the direction  8 , the conveyor device  13  starts behind the block supplying device  16 . The conveyor device  13  comprises a work table  40  which is supported on the floor via supports and extends down to the device  15 . Running parallel to the direction  8 , numerous rows of bores  41  are provided in the work table  40  which lead to vacuum channels  42  disposed underneath thereof and which are open towards the top of the work table  40 . Each of the channels  42  is connected to a vacuum generation device  43 . The low pressure at the free end of the bores  41  causes strips  12  guided across thereof to be held accurately on the work table. Below the work table  40  are disposed numerous parallel conveyor belts  44  which are arranged next to each other and are deflected via deflection rollers  45 ,  46 , wherein the roller  45  is driven by a motor  47 . As can be seen in  FIG. 4 , numerous, for instance  20 , parallel conveyor belts  44  are present crosswise to the direction  8 . These conveyor belts  44  are only visible in  FIG. 4  because the work table is shown broken open at the respective locations. The conveyor belts  44  arranged next to each other are drivable independently from each other. Each conveyor belt  44  carries at least one slide  48 . Each slide  48  is provided with a pin  49  which is upwardly extendable for instance by pneumatic actuation. Above the conveyor belts  44 , the work table  40  has continuous longitudinal grooves  50  running parallel to the direction  8 , with the extended pins  49  being displaceable therein along the direction  8 . The pins  49  are dimensioned such that they are disposed below the work table  40  in the retracted state and are disposed above the top of the work table  40 , for instance several centimeters above the top, in the extended state and are thus able to be used for conveying the strips  12 . Each of the conveyor belts  44  is height-adjustable together with the slides  48  by means of two height adjustment devices  51 ,  52  which are mounted below the belts  44  on a frame  53  which carries the belts  44  and rollers  45 ,  46 . In  FIGS. 1 to 7 , the slides  48  are all shown in the same drawing plane as if they were disposed on the same conveyor belt  44 . This is a graphically simplified view. In fact, the slides  48  are in each case disposed on different conveyor belts  44  which are disposed in succession and are actuable independently from each other. 
         [0030]    The gluing device  14  comprises a frame  54  which is supported on the ground. An upper support device  56  is articulated to this frame and above said frame via a joint  55 . The joint  55  is located at the end of the support device  56  pointing in the direction  8 . At the end opposite to the direction  8 , a height adjustment device  57  is mounted to the frame  55 , said height adjustment device  57  being able to pivot the device  56  about the joint  55  by means of one or several vertically extendable pins  58 . A glue application roller  59 , whose axis  60  is horizontal and perpendicular to the direction  8 , is mounted for rotary drive in the support device  56 . On the right of  FIG. 6  above the roller  59  is located a squeeze roller  61  with an axis  62  which is parallel to axis  60 . The surface of the roller  61  is in direct contact with the surface of the roller  59 , wherein the gap between the two rollers  59 ,  61  is adjustable to ensure a defined amount of glue is applied on the roller  59 . The rollers  59  and  61  are drivable for rotation by means of a drive belt  63  which is guided around the shaft  64  of a motor  65 , around a shaft  66  of the roller  59 , a shaft  67  of the roller  61  and a deflection roller  68 . Between the rollers  59  and  61 , a substantially triangular space  69  is formed above the rollers  59 ,  61  which is filled with glue. In a direction crosswise to the direction  8 , the space  69  is on both sides delimited by glue dams (not shown) whose contour is adapted to that of the rollers  59  and  61  in the triangular space. The glue dams may be displaceable crosswise to the direction of conveyance. The height adjustment device  57  enables the gap  70  to be adjusted between the lowest point of the roller  59  and the top of the strips  12 , thus ensuring an optimal application of glue on the top of the strips  12 . 
         [0031]    The corrugated-cardboard-strip turning device  15  comprises a turning roller  72 , having an axis  73 , which is supported on a frame  71  and is mounted for rotary drive. The roller  72  is drivable for rotation via a drive belt  74  by means of a motor  75 . The turning roller  72  comprises several spaced-apart rings  76  which are uniformly distributed across the width of the roller  72  and are rigidly connected to the cylindrical surface  77  of the roller  72 . Ribs  78  extending parallel to the axis  73  are inserted in respective grooves  79  in the rings  76  and are rigidly connected to the respective ring  76 , for instance by screws, gluing or welding. It is advantageous if the ribs  78  are fastened such as to be replaceable. In the present case, each ring  76  is provided with three rib  78  which are uniformly distributed across the periphery, in other words, they are disposed at an angle of 120° with respect to each other. The ribs  78  at the various rings  76  are all disposed at the same angular height, in other words they are in line with each other in the direction of the axis  73 . The ribs  78  are provided with numerous outwardly projecting needles  80 . The needles  80  are for instance arranged on a matrix of 2×15. The needles  80  are made of steel and have a pointed tip at their radially outer end. The needles  80  typically project from the top of the rib  78  by 3 mm to 10 mm, preferably by 5 mm. Relative to a direction of rotation  81 , the needles  80  do not point outwardly in an exactly radial direction but opposite to the direction of rotation  81 . Thus, they make an angle b with a radius through the axis  73 , wherein to said angle b applies 70°≦b≦110°, preferably b≈80°. This facilitates the removal of the strips  12  pinned thereto. On the right of  FIG. 1  above the roller  76 , there is a horizontal beam  82  which extends across the width of the roller  76  and has a broadened portion  83  at its front end pointing in the direction  8 . The beam  82  is actuable for displacement along and opposite to the direction  8  by means of a pneumatic device  84  arranged opposite to the direction  8 . Seen in the direction  8  directly above the roller  72  and beyond the highest point thereof, there is a stripping plate  85  which extends across the width of the roller  72 . Opposite to the direction  8 , the plate  85  has a front stripping edge  86  which is interrupted by rectangular recesses  87 . Relative to the axis direction  73 , the recesses  87  are disposed at those locations where the roller  72  is provided with the rings  76  comprising the needles  80 . This way, the stripping edge  86  can be arranged as closely as possible near the top of the roller  72  without leading to a collision with the needles  80 . As shown in  FIG. 1 , above the stripping plate  85  is located a hold-down device  88  for holding down the strips  12  stripped off the needles  80 . Said hold-down device  88  comprises a plate  90  which is articulated to a joint  89  and is height-adjustable by means of pneumatic cylinders  91  at its end opposite to the direction  8  for adjusting the inclination angle of the plate  90 . Seen in the direction  8  directly behind the stripping plate  85 , there is an endless, driven conveyor belt  94  which is deflected by means of two deflection rollers  92 ,  93 . The roller  92  is driven for rotation by means of a motor  95 . Above the conveyor belt  94 , there is a second conveyor belt  96  which is parallel thereto and deflected by means of deflection rollers  97 ,  98 , wherein the roller  97  is driven by means of a motor  99 . Between the conveyor belts  94  and  96  is formed a gap  100  through which the produced corrugated honeycomb cardboard  1  is discharged in the direction  8 . The conveyor belt  96  and the deflection rollers  97 ,  98  are fastened to a common frame  101  which is height-adjustable by means of height adjustment devices  102 ,  103 . This way, the width of the gap  100  is adjustable and adaptable to the respective thickness of the corrugated honeycomb cardboard  1 . 
         [0032]    Seen in the direction  8  behind the device  15 , there is a cutting device (not shown) for producing sheets of corrugated honeycomb cardboard  1 , as it is generally known from corrugated cardboard machines, for instance from DE 103 12 600 A1. The sheets are stacked in a stacking device (not shown). 
         [0033]    The following describes the functioning of the machine for producing corrugated honeycomb cardboard  1 . Glued together to form a block  2 , sheets of corrugated cardboard are supplied to the block supplying device  16 , wherein the topmost web of the block  2  is advantageously a corrugated web  3  while the bottommost web of the block  2  is a liner  4 . The channels  7  in the block  2  are all parallel to each other, extending horizontally and along the direction  8 . The conveyor belts  17  and  22  move the block  2  in a slip-free manner in the direction  8  but are also able to move the block  2  in a direction opposite to the direction  8 . As soon as the front edge of the block  2  pointing in the direction  8  has reached the level of the circular knife  39 , several pins  49  are extended in a uniformly distributed manner across the width of the work table  40  so as to be in contact with the front end of the block  2 . Afterwards, strips  12  are cut out from the block  2  by means of the circular knife  39 , wherein the block  2  is advanced across a particular distance by means of the belts  17 ,  22  after each cut, causing the extended pins  49 , which are in contact with the front end of the block  2 , to follow accordingly. Once the respective advance is complete, another cut is performed by the circular knife  39 , resulting in another strip. After a particular number of cuts, for instance  20  cuts, the block  2  is moved back opposite to the direction  8  by means of the belts  17 ,  22 . Afterwards, pins  49  of respective slides  48  are extended directly behind the rearmost slice  12  such that the group of adjacent strips  12  is delimited by pins in and opposite to the direction  8 , as for example shown in  FIG. 3 . The cluster  104  of adjacent strips  12  thus formed is now moved in the direction  8  by the synchronous movement of the respective slides  48 . The cluster  104  is passed below the glue application roller  59  which applies glue to the upper elevations of the topmost corrugated web  3 . The advantage of applying glue to the elevations of the corrugated web  3  is that less glue is required than for the liners  4 . Applying glue to the elevations of the corrugated webs  3  ensures that glue is applied only in those regions where it will ultimately be required. In this process, the glue passes from the space  69  through the gap between the rollers  59  and  61  before reaching the gluing gap  70 . Afterwards, the cluster  104  is moved in the direction  8  towards the corrugated-cardboard-strip turning device  15 . The roller  72  is in the position shown in  FIG. 7 , with the needles  80  being disposed directly above the work table  40 . When seen in the direction  8 , the first strip  12  is pressed onto the needles  80  by means of the extended pins  49  at the rear end of the cluster  104 . Before that, the pins  49  delimiting the front end of the cluster  104  had been retracted. In case the pressing force applicable to the rear end of the cluster  104  by means of the pins  49  does not suffice for pressing a strip  12  onto the needles  80 , the rear pins  49  can be retracted as well. They would then be replaced by a beam (not shown) which presses the cluster  104  onto the pins  80  across the entire width of the roller  72 . As soon as a strip  12  has been pressed onto the needles  80 , the roller  72  is rotated in the direction of rotation  81  until the strip  12  pinned to the needles  80  comes into contact with the stripping edge  86  which strips the strip  12  off the needles  80 . The engaged needles  80  are rotated through the recess  87  so as to be disengaged from the strip  12 . Afterwards, the strip  12 , which has been turned through 90°, is displaced by means of the beam  82  along the plate  85  in the direction  8  so as to pressed and glued to the strip  12  disposed in front thereof. This results in a theoretically endless web of corrugated honeycomb cardboard  1 .  FIG. 10  shows two strips  12  of the block  2  which are glued to each other. The corrugated honeycomb cardboard  1  is discharged by means of the conveyor belts  94  and  96  in the direction  8  before it is cut into sheets which are stacked. 
         [0034]    As already described at the outset, the corrugated honeycomb cardboard  1  has numerous advantageous properties, such as a high stiffness with respect to forces acting perpendicular to plane  10 . The corrugated honeycomb cardboard  1  is applicable as an insulating material, construction material, etc, and has a very low weight in relation to its external volume.