Abstract:
A clamping device and a laser welding apparatus using the same are disclosed. The clamping device may include: an upper clamping link mounted rotatably upwardly or downwardly by a hinge shaft; a lower clamping link mounted rotatably in an opposite direction of the upper clamping link by the hinge shaft and corresponding to the upper clamping link; at least two upper rollers rotatably mounted at the upper clamping link; at least two lower rollers rotatably mounted at the lower clamping link, corresponding to the upper roller, and fixing a welding object together with the upper rollers; and an operating cylinder configured to rotate the upper clamping link and the lower clamping link in opposite directions to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2012-0085686 filed in the Korean Intellectual Property Office on Aug. 6, 2012, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    (a) Field of the Invention 
         [0003]    The present invention relates to a clamping device and a laser welding apparatus using the same. More particularly, the present invention relates to a clamping device and a laser welding apparatus using the same which can fix a welding object using a roller and maintain a welding gap. 
         [0004]    (b) Description of the Related Art 
         [0005]    Generally, a clamping device fixes a material not to move at working process of the material such as cutting, sheet metal working, welding, and so on. 
         [0006]    Particularly, the clamping device is typically mounted on a jig in a welding device which performs welding process after a welding object is fixed using the jig. The clamping device fixes the welding object and maintains welding intervals if a plurality of welding points exists on the welding object at laser welding. 
         [0007]    Such a clamping device includes one or more clampers fixing the welding object, a hydraulic pressure cylinder or a pneumatic pressure cylinder operating the clamper, and mechanical elements such as links delivering movement of the cylinder to the clamper. 
         [0008]    Since the welding object is fixed and the welding intervals of the welding object are maintained using a plurality of clampers in a case that a plurality of welding points is laser-welded using a conventional clamping device, however, the number of must-be-used clampers may be increased. 
         [0009]    If the number of the must-be-used clampers increases, manufacturing cost of jigs of the welding apparatus may be increased. In addition, intervals between the welding points may be restricted because a plurality of clampers is disposed on the jigs having a restricted size. Furthermore, welding may not be performed and interference among a plurality of clampers, the welding apparatus, and the welding object may occur in a case that welding points of the welding object are closely located to each other. Therefore, the welding object may be welded badly. 
         [0010]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention has been made in an effort to provide a clamping device and a laser welding apparatus using the same having advantages of maintaining welding intervals using rollers, reducing manufacturing cost by simplifying a laser welding jig, and performing laser welding smoothly regardless of the number of welding points. 
         [0012]    A clamping device according to one or more exemplary embodiments of the present invention may include: an upper clamping link mounted rotatably upwardly or downwardly by a hinge shaft; a lower clamping link mounted rotatably in an opposite direction of the upper clamping link by the hinge shaft and corresponding to the upper clamping link; at least two upper rollers rotatably mounted at the upper clamping link; at least two lower rollers rotatably mounted at the lower clamping link, corresponding to the upper roller, and fixing a welding object together with the upper rollers; and an operating cylinder configured to rotate the upper clamping link and the lower clamping link in opposite directions to each other. 
         [0013]    A pair of upper rollers may be mounted at a front end of the upper clamping link, a pair of lower rollers may be mounted at a front end of the lower clamping link, and each pair of the pair of upper rollers and the pair of lower rollers may be disposed with a predetermined distance so as to position a welding point of the welding object therebetween. 
         [0014]    The operating cylinder may be connected to rear ends of the upper clamping link and the lower clamping link so as to rotate the upper clamping link and the lower clamping link in opposite directions to each other. 
         [0015]    A laser welding apparatus according to another exemplary embodiment of the present invention may include: the clamping device; a laser scanner irradiating a laser beam to a welding point of a welding object; and a supporting structure having an upper portion at which the laser scanner is mounted and a lower portion at which the clamping device is mounted, and mounted on a floor of a welding workshop. 
         [0016]    The supporting structure may include: a base plate having a tetragonal plate shape so as to be mounted on the floor of the welding workshop; and a supporting beam standing perpendicularly on the base plate and fixing and supporting the laser scanner and the clamping device. 
         [0017]    A laser welding apparatus according to other exemplary embodiment of the present invention may include: the clamping device; a laser scanner irradiating a laser beam to a welding point of a welding object; and a supporting bracket having an upper portion at which the laser scanner is mounted and a lower portion at which the clamping device is mounted, and supporting the laser scanner and the clamping device. 
         [0018]    The supporting bracket may be mounted at a robot. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention. 
           [0020]      FIG. 2  is a side view of a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention. 
           [0021]      FIG. 3  is a perspective view of a clamping device according to an exemplary embodiment of the present invention with a welding object being fixed thereto. 
           [0022]      FIG. 4  is a perspective view for illustrating that a welding object is welded using a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention. 
           [0023]      FIG. 5  is a perspective view of a laser welding apparatus having a clamping device according to another exemplary embodiment of the present invention. 
           [0000]    
         
           
                 
               
                 
                 
                 
               
             
                 
                     
                 
                 
                   &lt;Description of symbols&gt; 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                     
                   10: supporting structure 
                   20: welding object 
                 
                 
                     
                   30: clamping device 
                   31: hinge shaft 
                 
                 
                     
                   32a, 32b: clamping link 
                   33: roller 
                 
                 
                     
                   34: operating cylinder 
                   40: laser scanner 
                 
                 
                     
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0025]      FIG. 1  is a perspective view of a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention, and  FIG. 2  is a side view of a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention. 
         [0026]    Referring to  FIG. 1  and  FIG. 2 , a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention includes a supporting structure  10  having an H-shape, the clamping device  30  mounted at a lower portion of the supporting structure and supporting and fixing a welding object  20 , and a laser scanner  40  mounted at an upper portion of the supporting structure  10  and irradiating a laser on the welding object  20  supported by the clamping device so as to perform welding. 
         [0027]    The supporting structure  10  includes a base plate  11  having a tetragonal plate shape and mounted on a floor of a welding workshop, and a supporting beam  12  standing perpendicularly on the base plate  11  and mounting and fixing the laser scanner  40  and the clamping device  30 . 
         [0028]    According to the present exemplary embodiment, it is exemplified but is not limited to that a cross-section of the supporting beam  12  has the H-shape. The cross-sectional shape of the supporting beam  12  may be determined by a person of an ordinary skill in the art. 
         [0029]    In addition, the supporting structure  10  may have any shape which can stably support the laser scanner  40  and the clamping device  30 . 
         [0030]    The laser scanner  40  performs welding by irradiating the laser to the welding object  20 . The laser scanner  40  is well known to a person of an ordinary skill in the art, and thus detailed description thereof will be omitted. 
         [0031]    A supporting bar  13  is mounted at the upper portion of the supporting beam  12 . The supporting bar  13  is extended perpendicularly from the supporting beam  12 , an end of the supporting bar  13  is fixed to the upper portion of the supporting beam  12 , and the laser scanner  40  is mounted at the other end of the supporting bar  13 . 
         [0032]    The clamping device  3  is positioned under the laser scanner  40  and is fixed to the supporting beam 12 through a suitable mounting bracket. 
         [0033]    The clamping device  30  includes an upper clamping link  32   a  and a lower clamping link  32   b  mounted so as to be rotatable upwardly or downwardly by a hinge shaft  31 , at least two upper rollers  33  rotatably mounted at a front end of the upper clamping link  32   a  and disposed horizontally apart from each other with a predetermined distance, at least two lower rollers  33  rotatably mounted at a front end of the lower clamping link 32 b  and corresponding to the at least two upper rollers  33 , and an operating cylinder  34  connecting rear ends of the clamping links  32   a  and  32   b  and rotating the clamping links  32   a  and  32   b  simultaneously. 
         [0034]    The operating cylinder  34  may be a hydraulic pressure cylinder, pneumatic pressure cylinder, or any type of cylinders. 
         [0035]    Referring to  FIG. 2 , operation of the operating cylinder  34  is controlled by a controller (not shown). 
         [0036]    If the controller moves the operating cylinder  34  rearward, the upper clamping link  32   a  rotates downwardly with respect to the hinge shaft  31  but the lower clamping link  32   b  rotates upwardly with respect to the hinge shaft  31 . 
         [0037]    In this case, since a distance between the upper and lower rollers  33  mounted at the front ends of the upper clamping link  32   a  and the lower clamping link  32   b  narrows, the welding object  20  moving between the upper and the lower rollers  33  is fixed therebetween. 
         [0038]    If the controller, on the contrary, moves the operating cylinder  34  forward, the upper clamping link  32   a  rotates upwardly with respect to the hinge shaft  31  but the lower clamping link  32   b  rotates downwardly with respect to the hinge shaft  31 . 
         [0039]    In this case, since the distance between the upper and lower rollers  33  mounted at the front ends of the upper clamping link  32   a  and the lower clamping link  32   b  widens, the welding object can be extracted from the upper and lower rollers  33 . 
         [0040]      FIG. 3  is a perspective view of a clamping device according to an exemplary embodiment of the present invention with a welding object being fixed thereto. 
         [0041]    Referring to  FIG. 3 , a plurality of welding points  21  that will be welded is disposed on the welding object  20  along a length direction of the welding object  20 . 
         [0042]    The welding points  21  are continuously disposed with predetermined distances along the length direction of the welding object  20 . The welding points  21  are positioned between the two upper or lower rollers  33  and are moved between the upper and lower rollers  33  by a robot or any suitable transfer apparatus. 
         [0043]      FIG. 4  is a perspective view for illustrating that a welding object is welded using a laser welding apparatus having a clamping device according to an exemplary embodiment of the present invention. 
         [0044]    Referring to  FIG. 4 , in a state that the welding points  21  of the welding object  20  are moved between the upper and lower rollers  33  by the robot or any suitable transfer apparatus, the laser scanner  40  irradiates the laser beam  41  on the welding points  21  so as to weld the welding points  21 . 
         [0045]    The welding points  21  are controlled to be positioned between the two upper or lower rollers  33 , and the laser scanner  40  irradiates the laser beam  41  between the two upper or lower rollers  33 . Therefore, welding interval between the welding points  21  may be maintained to be constant. 
         [0046]    In addition, if the welding points  21  are closely positioned with each other, welding is smoothly performed by the laser beam irradiated between the two upper or lower rollers  33 . 
         [0047]    Since the welding object is fixed and the welding interval is maintained by a pair of clamping links  32   a  and  32   b  and two pairs of rollers  33 , a plurality of clampers for maintaining the welding interval is not necessary. Therefore, a jig structure of the laser welding apparatus may be simplified and manufacturing cost of the jig structure may be lowered. 
         [0048]      FIG. 5  is a perspective view of a laser welding apparatus having a clamping device according to another exemplary embodiment of the present invention. 
         [0049]      FIG. 5  illustrates a laser welding apparatus according to another exemplary embodiment of the present invention. That is, the laser scanner  40  and the clamping device  30  are mounted using a supporting bracket  50  instead of the supporting structure  10  according to another exemplary embodiment of the present invention. 
         [0050]    Since the laser scanner  40  and the clamping device  30  are mounted using the supporting bracket  50  and the supporting bracket  50  is fixed to a robot (not shown), the laser welding apparatus of robot type may be realized. Since other components according to another exemplary embodiment of the present invention are the same as those according to an exemplary embodiment of the present invention, detailed description will be omitted. 
         [0051]    Since the welding object can be rotatably supported and be fixed using the rollers mounted at the clamping links that can be rotatable upwardly or downwardly according to an exemplary embodiment of the present invention, the welding object may be stably fixed before performing the welding process and the welding interval between the welding points may be maintained to be constant. 
         [0052]    Since a plurality of clampers for fixing the welding object is not needed to be mounted at the jig, the jig structure may be simplified and manufacturing cost of the jig may be lowered. 
         [0053]    In a case that a plurality of welding points is positioned closely with each other on the welding object, the welding point may be disposed between the rollers. Therefore, welding process may be smoothly performed and welding productivity may be improved. 
         [0054]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.