Patent Publication Number: US-2002000142-A1

Title: Arrangement for cutting off a projecting cover layer and method of coating plates

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
       [0001] The present invention relates to an arrangement for cutting off a projecting cover layer and to a method of coating plates which are covered in a coating system by a cover layer whose borders project over the edges of the plates and are cut off.  
       [0002] In the case of coating systems of this type, a cover layer made of paper, plastic or other cuttable materials is applied to a plate web and is then hardened. The cover layer, which can be produced in different thicknesses, may be brittle or flexible. It is wider at the lateral edges than the plate web because, as a result of manufacturing tolerances in the material and process. After the coating, the projecting borders of the cover layer are cut off.  
       [0003] In the case of currently known methods for cutting off borders of the cover layer, the cover layer is either sawed, in which case a small foil projection at the longitudinal edges is left, or the carrier plate is cut, milled or ground simultaneously with the sawing of the cover layer. During the milling and grinding, a removal of material again takes place at the lateral edge of the carrier plate.  
       [0004] The trimming of the longitudinal edges in the case of the known coating systems has the disadvantage that the known cutting devices require relatively high expenditures. For the sawing on the opposite sides, two motors and, for the grinding or milling, even four motors are required for driving the cutting tools. Another disadvantage is that either a foil projection is left at the longitudinal edges, or the carrier plate is always machined at the lateral edges results in waste and dust which requires disposal. The plates must therefore also be produced with an overdimension. In addition, the known systems cannot compensate width tolerances but cut off the cover layer and/or the carrier plate always in the previously adjusted position.  
       [0005] It is therefore an object of the present invention to provide an arrangement for cutting off projection of a cover layer and a method for coating plates in the case of which the cover layer can be cut off with high precision and which can be mounted by simple devices in or behind a coating system. In addition, the occurrence of dust and waste materials is to be reduced.  
       [0006] This object is achieved by the present invention.  
       [0007] A rotating cutting edge is guided along the edge of the object. The cutting edge can at least partially move along with the object and the projecting cover layer, so that the relative speed between the cutting edge and the cover layer to be cut off is minimized. In the case of a more brittle cover layer, this prevents component parts from coming off the object. In addition, such a rotating cutting edge can be guided with little wear in a simple manner on a lateral edge of an object. In which case the plate-shaped object can be used as a cutting counter edge.  
       [0008] According to a preferred embodiment of the invention, the cutting device has a rotating cutting wheel which is arranged partially next to the edge of the object. As a result, the cutting edge can be used for cutting off the cover layer as well as for the guiding on the lateral edge of the object. In order to obtain a clean contact on the lateral edge, the cutting wheel can be prestressed toward the edge of the object with the projecting cover layer. As a result, plate-shaped objects can also be trimmed which have a diagonally or angularly extending lateral edge. In addition, manufacturing tolerances can be compensated more easily.  
       [0009] According to a preferred embodiment of the invention, the object is guided on the edge with the projecting cover layer, so that a sideways movement of the object outside certain tolerances is avoided. The sideways movement may cause damage to the cover layer on the cutting device. This guide is preferably elastic so that manufacturing tolerances during the manufacturing of the plate-shaped object can be compensated. The term plate-shaped object means in this case that the cover layer is applied at least in areas in a plane on the object; however, the objects can also be profiled, curve or shaped in a different manner.  
       [0010] According to a further development of the invention, a coating system is provided with an arrangement for applying a cover layer to the top side and/or the underside of a plate-shaped object, which have at least one arrangement according to the invention for cutting off a projecting cover layer on each side of the plate-shaped object. At least one suction device is provided on the coating system for removing a cut-off strip of the cover layer in a simple manner.  
       [0011] The above-mentioned object is also achieved by a method having the characteristic of claim  10 . According to the method, first a cover layer is applied to a plate-shaped object, for example, a derived timber product web, with ends projecting at the side, which object is then transported to a cutting device having at least one cutting wheel. The cutting wheel is rotated such that, viewed in the transport direction, the cutting edge impacts diagonally from the front onto the cover layer and the area of the cover layer projecting beyond the lateral edge of the object is cut off.  
       [0012] According to a preferred embodiment of the method, the plate-shaped object is guided elastically on both sides and the projecting area of the cover layer is cut off at the opposite sides As a result, manufacturing tolerances on the plate-shaped object can be compensated better during the cutting-off of the cover layer.  
       [0013] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014]FIG. 1 is a frontal view of a cutting device according to the invention; and  
     [0015]FIG. 2 is a schematic lateral view of a part of the cutting device of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0016]FIG. 1 is a detailed view of such a cutting device  11 . The cutting device  11  has a cutting wheel  12  which is provided with a cutting edge  13  on the side facing the plate  1 . The cutting wheels  12  of the cutting device  11  are made of hardened steel in order to be wear-resistant. Other materials, such as ceramics, can also be used.  
     [0017] The cutting edge  13  projects from the wheel  12 . A recess  14  is made in the cutting wheel  12 , so that, in the area of the recess  14 , no contact exists between the plate  1  and the cutting wheel  12 . The cutting wheel  12  is driven by a gummed wheel  15  which is guided on the top cover layer  8  of the plate  1 . As a result of the transport movement of the plate  1 , the wheel  15  rotates, which is guided with a slight pressure on the cover layer  8 , and thus drives the cutting edge  13 , which is guided along a lateral edge  25  of the plate  1 . The rotating cutting wheel  12  is rotatably disposed on a holder  19  and is biased by a spring  18  toward the plate  1 . The spring  18  is guided in a receiving device  17 .  
     [0018] In order to be able to adjust the cutting device  11  to different plate widths, the holder  19  is movably held on a cutting wheel application device  20 , so that the holder  19  can be adjusted along the cutting wheel application device  20 . The cutting wheel application device  20  is connected with a frame  21 .  
     [0019] In the lower area of the cutting device  11 , an elastically constructed ruler  24  is provided which is fixed on a stop  23  received on a guide  22 . The stop  23  is movably held on the guide  22  and ensures by way of the ruler  24 , that the plate  1  is laterally guided within an area.  
     [0020] In the illustrated embodiment, the plate  1  is provided with a cover layer  8  on the top side and on the underside. The cover layer  8  has projecting ends  26 ,  28  and  29 , the cutting-off of these ends  26 ,  28  and  29  taking place as illustrated in FIG. 1. Preferably, a cutting device  11  for cutting off the projecting area  29  is provided in a mirror-inverted manner on the opposite side  27  of the plate  1 .  
     [0021] As illustrated in FIG. 2, the cutting wheel  12  rotates in the area of the plate  1  in the transport direction so that the relative movement between the cutting wheel  12  and the plate  1  is slight during the contact. The cutting edge  13  of the cutting wheel  12  impacts diagonally from above onto the projecting section  31  of the cover layer  8 . The projecting section  31  is squeezed downward and the plate  1  which acts as a counterblade for the cutting edge  13  to shear the projecting section  31 .  
     [0022] The cut-off strip  32  of the cover layer  8  can be removed by a suction device  33 .  
     [0023] The cutting wheel  12  may be arranged with the axis of rotation of the cutting wheel at an angle with respect to the perpendicular line of the transport direction. Thus, the leading area of the cutting wheel  12  which first comes in contact with the cover layer  8  is arranged slightly closer to the edge  25  than the rearward trailing area of the cutting wheel  12 . As a result, it prevents the lateral edge  25  from damaging the rearward trailing area of the cutting wheel  12 .  
     [0024] In the case of the coating system according to the invention, four cutting devices  11  may be provided, each for cutting off a projecting section of the cover layer  8 . In this case, the upper and lower cutting devices  11  can be applied offset with respect to one another in order to guide the plate  1  successively through the individual cutting devices  11  The cutting devices  11  are a vertically adjustable in order to be able to move through different plate thicknesses as well as horizontally adjustable.  
     [0025] Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.