Abstract:
An apparatus ( 1 ) for grooving cardboard cuttings ( 2, 141 ) while the cuttings are transported past at least one groove cutting tool ( 72′, 72″, 72′″ ). The tool or tools are situated on a guide element ( 78, 80, 130 ) that can be moved relative to the transport device during the operation of the grooving apparatus. During a grooving operation, the position of the groove cutting tool along the surface of the cutting and/or its distance from the transport device, can be varied such that completely new designs of mechanically grooved cardboard cuttings can be realized. According to the grooving method at least one groove cutting tool is moved transverse to the transport direction of the cardboard cuttings while the cardboard cuttings are transported past the groove cutting tools.

Description:
BACKGROUND 
       [0001]    The present invention pertains to an apparatus and a method for grooving cardboard cuttings. 
         [0002]    Book cases, as well as boxes for high-quality sales and gift packages, essentially consist of cardboards that are lined with cloth materials. In order to prepare bending points or sharp-edged bends, the cardboard cuttings are grooved at the corresponding locations. The groove cross section may have any profile from triangular to rectangular that is cut out of the cardboards in the form of waste with knife blades that are accordingly aligned relative to one another or circular knives and, if applicable, an intermediately arranged lift-out device or with one-piece special knives that are shaped in accordance with the respective cross section. 
         [0003]    CN 101200091 B discloses a corresponding cardboard grooving machine with a driven transport drum and belts that are partially wrapped around the transport drum, wherein several groove cutting tools that can be stationarily positioned between the belts on the circumference of the transport drum are provided for cutting grooves that respectively extend parallel to one another. The groove cutting tools are respectively composed of two knife blades that are mounted on a knife holder, wherein the knife holders are situated on clip-on holders clamped onto one of two crossbeams. In order to position the groove cutting tools, the clip-on holders are manually displaced on the crossbeams axially to the transport drum and fixed in position. The groove depth is adjusted by means of a knurled thumb screw that effectively displaces the knife holder on the clip-on holder radially to the transport drum. 
         [0004]    The stationarily positioned groove cutting tools only make it possible to produce continuous grooves that extend parallel to the transport direction of the cardboard cuttings and have a constant cross section. However, there is a need to produce grooves sectionally, particularly in folding box constructions that consist of lined cardboard cuttings. 
       SUMMARY  
       [0005]    It is the object of the present invention to provide an apparatus and a method for grooving cardboard cuttings that achieve increased flexibility and allow diverse designs of grooved cardboard cuttings. 
         [0006]    A significantly improved flexibility of the grooving apparatus can be achieved with at least one groove cutting tool arranged in the apparatus on a guide element that can be moved relative to the transport drum and driven by a drive element during the operation of the grooving apparatus. The axial position of the at least one groove cutting tool on the transport drum and/or its distance from the drum surface can be purposefully varied during a grooving process, i.e., while a cardboard cutting is moved past the groove cutting tools. This makes it possible to realize completely new designs of mechanically grooved cardboard cuttings that until now had to be elaborately produced by hand or could not be produced at all. Cross sections that change along a groove or grooves that extend only sectionally and/or obliquely to one another provide new design options and functionalities for the boxes and book cases manufactured of the grooved cardboard cuttings. 
         [0007]    If the guide element can be moved and driven radially to the transport drum, it is possible to cut non-continuous grooves with ends and/or interruptions that are spaced apart from the cardboard edge along the groove. In this case, the respective groove cutting tool effectively is moved forward and backward from a cutting position into a raised position, in which it is lifted off the cardboard cutting, and/or vice versa while the cardboard cutting is moved past the groove cutting tool. For this purpose, the guide element in the form of a rocker or slide may be driven by a simple pneumatic cylinder. Grooves with a variable cross section along the respective groove can be cut by moving the groove cutting tool into cutting positions, in which it is spaced apart from the transport drum by different distances. 
         [0008]    If the guide element includes a slide that can be displaced and driven axially to the transport drum, it is possible to produce grooves that extend obliquely to one another and/or to the cardboard edge by continuously moving the respective groove cutting tool transverse to the cardboard transport direction in accordance with the progression of the groove during the groove cutting process. 
         [0009]    If the groove cutting tool is arranged on a guide element in the form of a cross-support, the groove cutting tool can be independently displaced radially and axially to the transport drum in order to simultaneously realize the aforementioned groove characteristics as a result of these axial and radial motions. 
         [0010]    Respective groove cutting tools may be individually arranged and driven on separate guide elements or, according to an enhancement, arranged in pairs or groups on a common guide element and driven by a common drive in order to produce the respective aforementioned groove characteristics several times in an identical fashion. 
         [0011]    The motion of the guide element preferably can be adjusted or changed. This makes it possible to flexibly produce grooves that are variable with respect to their cross section and/or progression. 
         [0012]    The advantages of a particularly high flexibility and optional automation are achieved due to the fact that the drive element consists of a controllable drive. The controllable drive is preferably connected to the drive of the transport drum by means of a control device. Due to the continuous balance with the transport motion of the cardboard cutting, the beginning and the end of the grooves, the progression and/or desired cross-sectional changes can be produced in the cardboard cutting in a positionally accurate fashion. If the motion of the guide element is controlled or variably controlled in accordance with a groove pattern that is defined by the shape and/or dimensions of a collapsible cardboard product manufactured of the cardboard cutting to be grooved, the grooves can be cut automatically without manual adjusting and refinishing processes by specifying the groove pattern resulting from the desired box. A particularly accurate motion control is achieved with a drive element in the form of a controlled electric motor. In addition to step angle-controlled electric motors, it is also possible to utilize linear motors, torque motors, moving coils (voice coils) or similar controllable electric drives. The guide element preferably can be driven in accordance with a curve in a program-controlled fashion. In this way, it is possible, in particular, the cut groove progressions that deviate from a straight line in a geometrically accurate fashion. If the curve can be varied, it is possible to flexibly produce grooves that are variable with respect to their progression. 
         [0013]    If the groove cutting tool comprises a scoring knife, it is possible to produce interrupted scores comparable to a perforation or sectional scores that define, e.g., a window cutout. If the scoring knives are adjusted to a corresponding depth, only a minimal residual cross section remains and can be very easily separated in subsequent production steps in order to remove corresponding sections or cutouts from the cardboard cuttings. Consequently, the punching of cardboard cuttings can be eliminated. 
         [0014]    According to the inventive method, at least one groove cutting tool is moved transverse to the transport direction of the cardboard cuttings while the cardboard cuttings are transported past the groove cutting tools. The inventive method for producing cross sections that vary along a groove or grooves that only extend sectionally and/or obliquely to one another is not only suitable for drum-type grooving machines, but also for linearly conveying grooving machines such as table grooving machines, in which the cardboard cuttings are transported on a linearly moving vacuum table, or grooving machines, in which the cardboard cuttings are transported by being clamped between several successively arranged pairs of transport rollers. 
         [0015]    The at least one groove cutting tool can be moved perpendicular to the cardboard cutting, preferably forward and backward from a cutting position into a raised position, in which it is lifted off the cardboard cutting, and/or vice versa in order to produce sectionally extending grooves. Grooves that extend obliquely to one another or to the cardboard edge can be produced by moving the at least one groove cutting tool perpendicular to the transport direction in the plane of the cardboard cutting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0016]    Exemplary embodiments and applications of the inventive grooving apparatus and the method are described in greater detail below with reference to the following figures. 
           [0017]    In these figures: 
           [0018]      FIG. 1  shows a schematic side view of a grooving apparatus with a groove cutting tool that essentially can be moved radially; 
           [0019]      FIG. 2  shows the groove cutting tool according to  FIG. 1  in the raised position; 
           [0020]      FIG. 3  shows an alternative design of a radially movable groove cutting tool; 
           [0021]      FIG. 4  shows a partially schematic perspective representation of a detail of a grooving apparatus with a groove cutting tool that is mounted on a cross-support; 
           [0022]      FIG. 5   a  shows a cardboard cutting that was sectionally grooved with the inventive grooving apparatus, and 
           [0023]      FIG. 5   b  shows a box manufactured of the grooved cardboard cutting according to  FIG. 5   a.    
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The grooving apparatus  1  schematically illustrated in  FIG. 1  essentially consists of a driven, horizontally supported transport drum  11  and several spaced-apart endless belts  51  that revolve around rollers  54  and are partially wrapped around the transport drum  11  such that an infeed  14  and an outlet  15  are formed, as well as groove cutting tools  72 ,  72 ′ that are arranged between the belts  51  at a defined distance from the drum surface. Cardboard cuttings  2  transported to the infeed  14  by a feed device  101  are pressed onto the drum surface in an effectively conveying fashion by the belts  51  and transported from the infeed  14  situated at the lower vertex of the transport drum  11  to the outlet  15  situated at the upper vertex in the transport direction  11  a during an approximately 180° rotation of the transport drum  11 , wherein the cardboard cuttings are during this process guided past groove cutting tools  72 ,  72 ′, at which, for example, a V-shaped waste section  6  is cut out of the cardboard cuttings  2  with correspondingly shaped grooving knives  71 . 
         [0025]    The feed device  101  in  FIG. 1  features a cardboard magazine  102  that contains a stack  4  of cardboard cuttings that lie on top of one another. The respective bottom cardboard cutting  2  is ejected underneath a front stop  103  by a first cardboard pusher  104 . 1  and transferred into an intermediate position, from which the cardboard cutting  2  is transported to the infeed  14  by a second cardboard pusher  104 . 2  while being aligned on outer guide rails  106 . The cardboard pushers  104 . 1 ,  104 . 2  are coupled at a fixed distance from one another and cyclically moved forward and backward with a constant transport stroke  107  that corresponds to this fixed distance. In this case, the transport speed is slightly higher than the rotational speed of the transport drum  11  such that the cardboard cuttings  2  effectively are forcibly pushed into the infeed  14  between transport drum  11  and belt  51 . 
         [0026]    The delivery  111  in  FIG. 1  features a delivery table  112  that slopes obliquely forward, wherein the completely grooved cardboard cuttings  3  exiting the outlet  15  are dropped onto said delivery table and placed on top of one another in order to form a stack  5 . Since the outlet  15  is arranged at the upper vertex of the transport drum  11 , the cut grooves  3  lie on the upper side of the exiting cardboard cuttings  3  and therefore are visible to the operator. 
         [0027]    According to  FIG. 1 , the rollers  54  are arranged around the transport drum  11  in such a way that a total of three areas of closest approach between the segments that lie between the rollers  54  and the belt sections adjoining the transport drum  11  are formed. The groove cutting tools  72 ,  72 ′ may be arranged in these areas. The groove cutting tools  72 ,  72 ′ are mounted on supporting beams  36 ,  37  that lie parallel to the transport drum  11 . Several groove cutting tools  72 ,  72 ′ may be mounted adjacent to one another. Grooves  3   a  that lie very close to one another can be produced due to the arrangement on two supporting beams  36 ,  37  that lie behind one another in the transport direction  11   a.    
         [0028]      FIG. 2  shows the inventive groove cutting tool  72 ′ according to  FIG. 1  on an enlarged scale. It consists of a carrier  73  that can be fixed on the supporting beam  36  with a clamping block  74 . A rocker  78  is supported on the carrier  73  and a receptacle slide  76  for the grooving knife  71  is mounted on the rocker. The rocker  78  is driven by a pneumatic cylinder  79  such that the grooving knife  71  is essentially moved back and forward between the cutting position illustrated in  FIG. 1  and the raised position according to  FIG. 2 , in which it is lifted off the cardboard cutting  2 , radially to the transport drum  11 . 
         [0029]    After loosening the clamping block  74 , the groove cutting tool  72 ′ can be displaced axially referred to the transport drum  11  such that the position of the groove  3   a  to be cut in the cardboard cutting  3  can be changed. In addition, the receptacle slide  76  can be released and displaced in an infinitely variable fashion radially to the transport drum  11  by means of a dial  77  such that a respective cutting depth can be adjusted in the cutting position. 
         [0030]    The pneumatic cylinder  79  is controlled by a pneumatic valve  81  that is connected to a control device  82 , in which the signals of a rotary encoder  84  that senses the rotational motion of the transport drum  11  and of a light barrier  83  that senses the front edge of the cardboard cutting  2  passing through the apparatus are processed in order to exactly determine the position of the cardboard cutting  2 . Since the groove cutting tool  72 ′ and the grooving knife  71  can be moved from a cutting position into a raised position, in which they are lifted off the cardboard cutting  2 , and vice versa in a respectively exact transport position while the cardboard cutting  2  passes through the apparatus, it is possible to cut non-continuous grooves with ends and/or interruptions that are spaced apart from the cardboard edge along the groove. 
         [0031]      FIG. 3  shows an alternative embodiment of a radially movable groove cutting tool  72 ″. A slide  80  that can be displaced radially to the transport drum  11  is guided on the carrier  73  and the receptacle slide  76  for the grooving knife  71  is arranged on said slide. The slide  80  and the grooving knife  71  are driven by the pneumatic cylinder  79  arranged parallel to the linear guide. 
         [0032]      FIG. 4  shows a third embodiment of a groove cutting tool  72 ″&#39;. It is mounted on a driven cross-support  130  consisting of a slide  136  that is driven axially referred to the transport drum  11  and a receptacle slide  131  for the grooving knife  71  that is guided and driven radially to the transport drum  11  on a carrier  134  arranged on the slide  136 . The receptacle slide  131  is driven by a servomotor  132  via a spindle-nut drive  133 . In this way, the grooving knife  71  can be moved into cutting positions, in which it is spaced apart from the transport drum  11  by different distances and grooves with a variable cross section along the respective groove can be cut. 
         [0033]    The slide  136  is realized in the form of a rotor or secondary component  136  of a linear motor  135  and guided axially to the transport drum  11  on the primary component  137  that acts as a stator and is mounted on the supporting beam  36 . Both drives, namely the servomotor  132  for the radial motion and the linear motor  135  for the axial motion of the grooving knife  71 , are connected to the driving motor  13  of the transport drum  11  by means of a control device  138 . This results in a particularly high flexibility with respect to cutting grooves that are spaced apart from the cardboard edge, interrupted grooves, obliquely extending grooves and/or grooves with varying cross section. In this respect, see also the preceding explanations in the description of advantages. The production of a groove section  3   a ′ that extends obliquely to the transport direction  11   a  is illustrated as an application example in  FIG. 5 . Grooves  3   a ′ that extend obliquely to one another are required, for example, for manufacturing asymmetric collapsible boxes. 
         [0034]    An example of a cardboard cutting that was grooved by means of the grooving apparatus  1  in accordance with the inventive method is illustrated in  FIG. 5   a .  FIG. 5   a  shows a flat cardboard cutting  141  intended for a box  140 . A bottom panel  143 , two opposing sidewalls  144   a, b  arranged on the bottom panel  143  and a cover panel  145  are formed in the cardboard cutting  141  by means of several V-grooves that were produced lengthwise. Transversely extending grooves  146   a, b  were not produced continuously, but rather cut into the bottom panel  143  and the two sidewalls  144   a, b  only. In addition, the cardboard cutting  141  also contains two grooves  147   a, b  that were produced in the sidewalls  144   a, b  mirror-symmetric to one another in an undulating fashion. 
         [0035]    In order to manufacture the cardboard cutting  141  illustrated in  FIG. 5   a , the V-grooves  142  and  147   a, b  that essentially extend lengthwise are produced in a first processing step. The grooving knives  72 ′″ for cutting the grooves  147   a, b  are moved back and forward transverse to the transport direction  11   a  of the cardboard cutting  141  in accordance with the undulating shape during the groove cutting process. The transversely extending grooves  146   a,b  are then produced in a second processing step, in which the cardboard cuttings  141  are fed to the grooving apparatus  1  after they were subjected to a 90° rotation. In this case, the groove cutting tools  72 ′,  72 ″ or  72 ′″ are respectively moved away from the transport drum  11  from a cutting position into a raised position, in which they are lifted off the cardboard cutting  141 , in order to exclude the cover panel  145 . 
         [0036]      FIG. 5   b  shows a box  140  manufactured of the grooved cardboard cutting  141 . The sidewalls  144   a, b  are positioned upright. Separate sidewalls  148   a, b  are inserted into the grooves  146   a, b  with key and slot joints and glued to the cardboard cutting  141 . An intermediate bottom  149  with the curvature defined by the grooves  147   a, b  is accommodated in the undulating grooves  147   a, b . Curvate sidewalls may be glued on the box in the same fashion. 
         [0037]    Boxes joined by means of key and slot joints have a high stability. The joining principle furthermore allows considerable manufacturing tolerances of the individual components because dimensional and geometrical deviations are concealed by the grooves. Furthermore, curvate sidewalls and (intermediate) bottoms and non-cuboid box constructions can be realized in connection with the inventive grooving method.