Patent Publication Number: US-7913619-B2

Title: Embossing apparatus

Description:
This application claims priority based on German Application No. 102006056701.3-14, filed on Nov. 30, 2006. 
     BACKGROUND OF THE INVENTION 
     The invention concerns an apparatus for embossing a decorative layer of an embossing film which is of a strip form, on to a small-radiused corner of a surface element. 
     An apparatus for embossing a decorative layer of an embossing film which is of a strip form on to the narrow sides, which delimit a surface element, of the surface element is known for example from DE 102 16 139 C1. With that known embossing apparatus it is possible for surface elements to be embossed at their narrow sides with the decorative layer of an embossing film which is of a strip form, at high cycle speeds, that is to say high cycle rates. If however the respective surface element has rounded configurations of a small radius at its corners, then the corresponding decorative layer portions at those corners have hitherto been fixed to the rounded corners for example by means of a tool which is to be operated manually. That manual mode of operation is however only possible at low cycle speeds or cycle rates so that the productivity correspondingly leaves something to be desired. The rounded configurations can for example involve a radius of between 2 mm and 5 mm, in which respect it will be appreciated that the corresponding problems also arise in relation to radii of different sizes. 
     For embossing rounded corners of surface elements, it is for example also possible to use a stroke embossing procedure as can be carried out for example with an embossing machine of the PE500/KTF ‘Touchwood’ type. However corners of a surface element, which involve a small radius, can only be embossed at moderate cycle speeds, when using an embossing machine of that kind. 
     Likewise it is possible for pin elements comprising a plastic material to be rolled in peripheral relationship against the surface element to be embossed, in which case the surface element to be embossed and the pin elements perform a relative movement with respect to each other during the decoration procedure. Higher embossing speeds can admittedly be achieved, in comparison with a stroke embossing procedure, when using such a known double embossing head; however, that higher speed still leaves something to be desired in comparison with an embossing apparatus in accordance with above-mentioned DE 102 16 139 C1, for embossing narrow sides of surface elements. That results for example from the insulating properties of the plastic pins of the double embossing head as the heat has to be transported from the interior of the punch or pressing member to the surface thereof, which requires a relatively large amount of time. The through-put of surface elements to be embossed, per unit of time, is correspondingly low. 
     SUMMARY OF THE INVENTION 
     In consideration of those factors the object of the invention is to provide an embossing apparatus of the kind set forth in the opening part of this specification, with which it is possible, at a high level of productivity, that is to say with a high embossing speed and with high cycle rates, to emboss small-radiused corners of a surface element with a decorative layer of an embossing film in strip form. 
     In an apparatus of the kind set forth in the opening part of this specification, in accordance with the invention that object is attained by a revolver head which is rotatable stepwise about an axis and which is provided at a linear drive device reciprocatingly movable between an embossing position and an inactive position and which at its periphery has a number of elastic pressing members, wherein a heating device for the pressing members is associated with the revolver head. 
     The configuration of the embossing apparatus according to the invention provides for a rapid supply of heat to the elastic pressing members. A freshly heated elastic pressing member is in a condition of embossing operation at any time so that a correspondingly high cycle speed is achieved. The term ‘elastic’ is used to denote a pressing member when the surface of the material from which the pressing member is formed is of a hardness in the range of between 45° Shore and 95° Shore, preferably in the range of between 60° Shore and 80° Shore, in particular about 70° Shore. 
     In that respect the elasticity of the surface of a pressing member is to be matched to the radius of the corner of the surface element, which is to be embossed upon. Thus at the periphery of the revolver head, the elastic pressing members are to be pressed against the surface element in the region of the radius of the corner thereof, in such a way that each pressing member adapts to the radius and thus leads to optimum transfer of the decorative layer on to the corner of the surface element. The smaller the radius is, the correspondingly more elastic is a pressing member accordingly to be. 
     In the case of the embossing apparatus according to the invention the linear drive device can be formed by a piston-cylinder device. 
     The pressing members can have at least at their surface silicone rubber, it may be desirable if the pressing members comprise silicone rubber. 
     The heating device for the elastic pressing members provided on the revolver head is preferably provided at the center of the revolver head. For that purpose the heating device is preferably provided at the axis of the revolver head. Likewise it is possible for the heating device to have heat radiating devices, between which the revolver head is disposed, wherein the heat radiating devices are preferably arranged in a plane oriented perpendicularly relative to the axis of the revolver head. 
     The revolver head with the associated linear drive device and the heating device are desirably provided on a main frame structure on which an embossing film supply roll, the film advance and direction-changing rollers and the take-up roll are mounted at associated mounting shafts. The mounting shafts for the embossing film supply roll, the film advance and direction-changing rollers and the take-up roll are preferably oriented in parallel relationship with the axis of the revolver head. 
     Optimum use of the apparatus according to the invention can be effected in that there are provided a number of main frame structures, that corresponds to the number of rounded corners of the respective surface element, wherein the revolver heads are reciprocatingly movable simultaneously between the embossing position and the inactive position. 
     It is highly productively possible with the embossing apparatus according to the invention to emboss the rounded corners of a surface element, which involve a small radius of for example between 2 and 5 mm, with an embossing film in strip form, wherein the corresponding cycle speeds are adapted to the cycle speeds of the embossing apparatus at which the narrow sides of the surface element are embossed with the embossing film in strip form. Those narrow surfaces can in that respect be of a straight or curved, wavy or any other configuration. The corners of the respective surface element, which are of a small radius, like its narrow sides, can be of a configuration involving a flat surface or a concavely or convexly curved shape. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details, features and advantages will be apparent from the description hereinafter of an embodiment by way of example of the embossing apparatus according to the invention. 
         FIG. 1  is a diagrammatical side view of the embossing apparatus of the present invention. 
         FIG. 2  is a diagrammatical side view of an alternative embodiment of the embossing apparatus of the present invention. 
         FIG. 3  is a schematic diagram of four embossing apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an embodiment of the embossing apparatus  10  which is provided for embossing a decorative layer of an embossing film  12  which is in the form of a strip, on to a small-radiused corner of a surface element (not shown). The embossing apparatus  10  has a main frame structure  14 , on which a revolver head  16  is rotatable stepwise about an axis  18 . The revolver head  16  is provided at a linear drive device  20 . The linear drive device  20  is formed by a piston-cylinder device  22 . The cylinder  24  of the piston-cylinder device  22  is fixed to the main frame structure  14 . The revolver head  16  is connected to the piston of the piston-cylinder device  22 . 
     The revolver head  16  is reciprocatingly movable between an embossing position and an inactive position by means of the linear drive device  22 . 
     At its periphery  26  the revolver head  16  has a number of elastic punch or pressing members  28 . The pressing members  28  comprise silicone rubber and are arranged uniformly spaced at the periphery  26  of the revolver head  16 . 
     A heating device  30  for the pressing members  28  is associated with the revolver head  16 . The heating device  30  is preferably provided in the center of the revolver head  16 , as shown in  FIG. 1 . It is particularly advantageous in that respect if the heating device  30  is provided in the axis  18  of the revolver head. Alternatively, it is possible for the heating device to have heat radiating devices, between which the revolver head is disposed, wherein the heat radiating devices are preferably arranged in a plane oriented perpendicularly relative to the axis of the revolver head, as shown in  FIG. 2 . 
     Reference  32  in the Figure denotes film direction-changing roller loops. 
     An embossing film supply roll  34  is mounted rotatably on a mounting shaft  36  on the main frame structure  14  of the embossing apparatus. Film advance rollers  38  and direction-changing rollers  40  are also rotatably mounted on the main frame structure  14  at associated mounting shafts  42 ,  44 . A take-up roll  46  for the carrier strip of the embossing film  12  is also rotatably mounted on the main frame structure  14  at an associated mounting shaft  48 . 
     Optimum use of the apparatus according to the invention can be effected in that there are provided a number of main frame structures, that corresponds to the number of rounded corners of the respective surface element, as shown in  FIG. 3 , wherein the revolver heads are reciprocatingly movable simultaneously between the embossing position and the inactive position.