Abstract:
The present invention relates to a wiper blade mounted to a wiper apparatus for a vehicle to wipe a windshield, a jig for heat treating a wiper frame of a wiper blade, and a method for machining a wiper frame using the same. An object of the present invention is to provide a wiper blade, which has a wiper frame formed to have elasticity, has an improved structure for securing a wiper strip, causes a wiper strip to be directly coupled with the wiper frame, and is easily assembled, thereby saving a time required for an assembling process and having improved durability and contacting force, a jig for heat treating a wiper frame of a wiper blade and a method for machining a wiper frame using the same. According to the present invention for achieving the object, there is provided a wiper blade for wiping a windshield, comprising a wiper strip in contact with the windshield, the wiper strip having rail grooves formed on both sides thereof; a wiper frame curved along its lengthwise direction and having elasticity to bring the wiper strip into contact with the windshield; a coupling slit formed in the wiper frame, the rail grooves of the wiper strip being slidably fitted to the coupling slit; and a coupling aperture formed in one end of the coupling slit and allowing the wiper strip to be inserted thereinto.

Description:
PRIORITY INFORMATION 
     This application claims priority to Korean Patent Application No. 10-2005-0115734, filed Nov. 30, 2005, entitled WIPER BLADE, JIG FOR HEAT TREATING WIPER FRAME OF WIPER BLADE AND METHOD FOR MACHINING WIPER FRAME USING THE SAME, which application is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a wiper blade mounted to a wiper apparatus for a vehicle to wipe a windshield, a jig for heat treating a wiper frame of a wiper blade, and a method for machining a wiper frame using the same, and more particularly, to a wiper blade of which a wiper frame is elastic and is mounted with a wiper strip to have a simple structure and be easily assembled, a jig for heat treating a wiper frame of a wiper blade and a method for machining a wiper frame using the same. 
     BACKGROUND 
       FIG. 1  is a perspective view of a vehicle to which a conventional wiper blade is mounted, and  FIG. 2  is a front view of the conventional wiper blade. 
     As shown in  FIG. 1  and  FIG. 2 , the conventional wiper apparatus comprises a wiper arm  15  installed at one side of a vehicle body  10  and rotated from side to side by a wiper motor (not shown), and a wiper blade  20  mounted to the wiper arm  15 , moved on and contacted with a windshield  12  to wipe it, and provided with a wiper strip  30 . 
     The wiper blade  20  is coupled with the wiper arm  15  and is rotated within a predetermined angle range according to operation of the wiper motor. To this end, a main link  22  of the wiper blade  20  is coupled with the wiper arm  15 . A plurality of intermediate links  24  are connected to the main link  22  through pins  25  for uniformly transmitting pressure of the wiper arm  15  to the main link  22 . A plurality of sub links  26  are connected to the intermediate links  24  with pins  27  to connect the intermediate links  24  to the wiper strip  30 . Also, clips  28  are formed at both ends of the sub link  26  and coupled with coupling grooves formed in the wiper strip  30 . 
     Further, the wiper blade  20  is provided with a joint  29  to reduce a friction force between the main link  22  and the intermediate links  24 . 
     In the wiper blade according to the prior art, however, a process of assembling a wiper strip as well as a structure for securing it are complicated, whereby there is a problem in that a time required for assembling the wiper blade is increased to lower a productivity of the articles. Also, in the conventional wiper blade, since the links are moved relative to each other when the wiper blade is operated, noises can be generated in the operation of the wiper blade. In addition, in the conventional wiper blade, the wiper blade is lifted up from the windshield by the wind when the vehicle is driven at a high speed, which causes a contacting force between the wiper blade and the windshield to be lowered. Accordingly, in order to solve the above problem, the structure in which an additional windbreak rib is provided on the main link has been proposed. However, a complete solution has not been proposed, so that there is a room for improvement of the wiper blade. 
     Technical Problem 
     The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a wiper blade, which has a wiper frame formed to have elasticity, has an improved structure for securing a wiper strip, causes a wiper strip to be directly coupled with the wiper frame, and is easily assembled, thereby saving a time required for an assembling process and having improved durability and contacting force, a jig for heat treating a wiper frame of a wiper blade and a method for machining a wiper frame using the same. 
     Technical Solution 
     According to an aspect of the present invention for achieving the object, there is provided a wiper blade for wiping a windshield, comprising a wiper strip in contact with the windshield, the wiper strip having rail grooves formed on both sides thereof; a wiper frame curved along its lengthwise direction and having elasticity to bring the wiper strip into contact with the windshield; a coupling slit formed in the wiper frame, the rail grooves of the wiper strip being slidably fitted to the coupling slit; and a coupling aperture formed in one end of the coupling slit and allowing the wiper strip to be inserted thereinto. Here, the wiper frame may have at least one coupling slit and the wiper strip may be formed corresponding to the coupling slit. In addition, any one of a through-hole and a protrusion may be formed between the coupling slits, and then, the other one of the through-hole and the protrusion may be formed in an upper end of the wiper strip to be inserted thereinto. Further, the wiper blade may comprise an auxiliary slit which is connected to an end of the coupling aperture and formed collinearly with the coupling slit. In addition, the coupling aperture that is connected to the coupling slit may be formed to be inclined in the fitting direction of the wiper strip. In the meantime, the wiper blade may further comprise a connector provided at one side of the wiper frame to be coupled with the wiper arm. Preferably, the wiper frame may be formed with a seating portion for guiding a connecting position of the connector. In addition, the wiper frame may be configured such that an area of one side of the wiper frame is increased as it goes to its center. Further, in a case where the wiper frame is arranged to be inclined at a predetermined angle, the wiper strip may be formed to be inclined with respect to the wiper frame to be brought into perpendicular contact with the windshield. Also, the connector to be coupled with the wiper frame may be formed to be inclined in the direction opposite to the inclination direction of the wiper frame. 
     According to another aspect of the present invention for achieving the object, there is provided a jig for heat treating a wiper frame of a wiper blade, comprising a first jig provided with a first working surface having a predetermined curvature to press an upper portion of a wiper frame workpiece; a second jig arranged opposite to the first jig and provided with a second working surface having a curvature corresponding to the first working surface to press a lower portion of the wiper frame workpiece; and a press for pressing the first and second jigs to form the wiper frame workpiece disposed between the first and second jigs. 
     Further, the first and second jigs may be provided with a heating means. Furthermore, the jig may further comprise an auxiliary jig disposed between a plurality of wiper frame workpieces placed between the first and second jigs, the auxiliary jig having a curvature corresponding to the first and second working surfaces. 
     According to a further aspect of the present invention for achieving the object, there is provided a method for manufacturing a wiper frame of a wiper blade, comprising the steps of heat treating a workpiece made of steel to obtain martensite; blanking the workpiece heat treated in the heat treating step to prepare a wiper frame workpiece for a wiper blade; piercing the wiper frame workpiece prepared in the blanking step to remove an unnecessary portion from the wiper frame workpiece; bending the wiper frame workpiece to be formed to have a predetermined curvature; and heat treating and forming the wiper frame workpiece to have a desired curvature by pressing it and simultaneously to relieve internal stress thereof through annealing. 
     Also, the step of heat treating may comprise the steps of heating the wiper frame workpiece at a transformation temperature or more; and rapidly cooling the wiper frame workpiece heated in the heating step. 
     Advantageous Effects 
     According to a wiper blade, a jig for heat treating a wiper frame of a wiper blade and a method for machining a wiper frame using the same of the present invention configured as above, there are the advantages in that a structure of a wiper frame for securing a wiper strip is simple, a process of assembling the wiper strip to the wiper frame is simple, a time required for the assembling process can be reduced, and the manufacturing costs can be remarkably reduced and the durability of the article can be significantly improved since the wiper frame is formed to have predetermined elasticity and therefore no additional part is necessary. It is also possible to form a plurality of wiper frames in a short time using the jig for heat treating a wiper frame. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a vehicle to which a conventional wiper blade is mounted; 
         FIG. 2  is a front view of the conventional wiper blade; 
         FIG. 3  is a perspective view of a wiper blade according to the present invention; 
         FIG. 4  is an exploded perspective view of the wiper blade according to the present invention; 
         FIGS. 5(   a ) and ( b ) are sectional views of a wiper strip of the wiper blade according to the present invention; 
         FIG. 6  is a sectional view of the wiper blade according to the present invention; 
         FIG. 7  is a plane view of a wiper frame of the wiper blade according to the present invention; 
         FIG. 8  is a plane view schematically showing a jig for heat treating a wiper frame according to the present invention; 
         FIG. 9  is a view showing a state where the wiper frame is machined in the jig for heat treating a wiper frame according to the present invention; 
         FIG. 10  is a view showing a state where a plurality of wiper frames are machined in the jig for heat treating a wiper frame according to the present invention; and 
         FIG. 11  is a flow chart illustrating a method for manufacturing the wiper frame of the wiper blade according to the present invention. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS FOR MAJOR PORTIONS SHOWN IN DRAWINGS 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                   
                 50: 
                 Wiper Blade 
               
               
                   
                   
                 60: 
                 Wiper Strip 
               
               
                   
                   
                 62: 
                 Body portion 
               
               
                   
                   
                 64: 
                 Upper End portion 
               
               
                   
                   
                 65: 
                 Rail Groove 
               
               
                   
                   
                 68: 
                 Strip portion 
               
               
                   
                   
                 69: 
                 Cut-out portion 
               
               
                   
                   
                 70: 
                 Wiper Frame 
               
               
                   
                   
                 74: 
                 Coupling Aperture 
               
               
                   
                   
                 76: 
                 Coupling Slit 
               
               
                   
                   
                 78: 
                 Auxiliary Coupling Slit 
               
               
                   
                   
                 80: 
                 Connector 
               
               
                   
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
     Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to accompanying drawings. 
       FIG. 3  is a perspective view of a wiper blade according to the present invention, and  FIG. 4  is an exploded perspective view of the wiper blade according to the present invention. Also,  FIGS. 5(   a ) and ( b ) are sectional views of a wiper strip of the wiper blade according to the present invention,  FIG. 6  is a sectional view of the wiper blade according to the present invention, and  FIG. 7  is a plane view of a wiper frame of the wiper blade according to the present invention. 
     As shown in  FIGS. 3 to 7 , a wiper blade  50  according to the present invention comprises a wiper strip  60  in contact with a surface of a windshield to wipe out moisture, dust and the like got on the surface of the windshield, and a wiper frame  70  with which the wiper strip  60  is coupled. 
     As shown in  FIG. 5(   a ), the wiper strip  60  includes a body portion  62 , rail grooves  65  formed in an upper end portion  64  of the body portion  62  to be opened to both sides, and a strip portion  68  formed in a lower end portion of the body portion  62  to be brought into contact with a surface of a windshield. 
     The wiper frame  70  exerts a certain elastic force to the wiper strip  60  such that the wiper strip  60  is brought into close contact with a windshield  12 . To this end, as shown in  FIG. 7 , the wiper frame  70  is made of a thin metal plate and is formed to be curved along the lengthwise direction. Also, the wiper frame  70  comprises coupling slits  75  extending in the lengthwise direction. At this time, each coupling slit  75 , which is a structure for coupling the wiper strip  60  thereto, has a predetermined width such that the rail grooves  65  of the wiper strip  60  can be fitted to the coupling slit. 
     In addition, a coupling aperture  74  is formed at one end of each coupling slit  75  so that a portion of the upper end portion  64  of the wiper strip  60  can be disposed in the coupling aperture in order to fit the rail grooves  65  of the wiper strip  60  to the coupling slit. 
     An end of the coupling aperture  74  connected to the coupling slit  75  is formed to be inclined in the fitting direction of the wiper strip  60 , and thus guides so that the rail grooves  65  of the wiper strip  60  are fitted to the coupling slit  75 . 
     In the meantime, only one of the coupling slits  75  may be formed in the wiper frame  70 . However, it is preferred that a plurality of coupling slits be successively formed in order to maintain the rigidity of the wiper frame  70  and make it easy to couple the wiper strip  60  thereto. Also, the wiper strip  60  is formed such that its upper end portion corresponds to the coupling slits  75  of the wiper frame  70 . That is, a cut-out portion  69  is formed in the upper end portion  64  of the wiper strip  60  by cutting out a part of the upper end portion  64  corresponding to a portion in which the coupling slit  75  is not formed. 
     Also, when the plurality of coupling slits  75  are formed in the wiper frame  70  as described above, a through-hole  82  may be formed between the coupling slits  75 . In addition, a protrusion  84  may be formed on the upper end portion of the wiper strip  60 , to be inserted into the through-hole  82  of the wiper frame  70 . Accordingly, as the protrusion  84  of the wiper strip  60  is inserted into the through-hole  82  of the wiper frame  70 , the wiper strip  60  and the wiper frame  70  are fixedly coupled. In the embodiment of the present invention, although it is described that the through-hole is formed in the wiper frame  70  and the protrusion corresponding to this through-hole is formed on the wiper strip  60 , it is possible to form a protrusion on the wiper frame  70  and a through-hole in the upper end portion of the wiper strip  60 . In addition, a plurality of the through-holes or protrusions may be formed, and a shape of the through-hole or protrusion may be variously modified. 
     Also, an auxiliary coupling slit  78  is formed in the wiper frame  70  to be connected to the other end of the coupling aperture  74 . The auxiliary coupling slit  78  is formed collinearly with the coupling slit  75  and fitted to the rail grooves  65  formed in an end of the wiper strip  60 . To this end, the other end of the wiper strip  60  is fitted to the coupling slits  75  via the coupling aperture  74 , and then, the one end of the wiper strip  60  is inserted into the coupling aperture  74  by compressing the one end of the wiper strip  60 . At this time, once the compression force exerted on the wiper strip  60  is removed, the rail grooves  65  formed at the one end of the wiper strip  60  is fitted to the auxiliary coupling slit  78 . 
     In the meanwhile, a connector  80  is installed to a portion of the wiper frame  70  to couple the wiper frame to a wiper arm  15  ( FIG. 1 ). Preferably, a seating portion  72  may be formed in the portion of the wiper frame  70  to guide a connecting position of the connector  80 . The seating portion  72  may comprises a step section which may be formed to have the length and width corresponding to a coupling section of the connector  80 . In addition, in order to increase the area which is exposed to wind, an area of a side of the wiper frame  70  is increased as it goes to its center. At this time, a central portion of the side of the wiper frame  70  of which the area is increased is partially cut out in order to couple the wiper frame with the connector  80 . 
     In the meantime, the wiper frame  70  may be arranged slantingly to be inclined at a predetermined angle in order to bring the wiper strip  60  into more close contact with the windshield by the wind. When the wiper frame  70  is arranged to be inclined as described above, the wiper strip  60  is formed to be inclined with respect to the wiper frame  70  so as to be brought into perpendicular contact with the windshield. 
     To this end, as shown in  FIG. 5(   b ), a wiper strip  160  has a body portion  162 , rail grooves  165  formed in an upper end portion of the body portion  162  to be opened to both sides, a strip portion  168  formed in a lower end portion of the body portion  162  to be brought into contact with a surface of a windshield. At this time, the body portion  162  may be formed in an inclined wedge shape and a groove section  169  (← 168 ) may be formed in a portion of the body portion  162  in order to reduce the weight and material cost of the wiper strip. 
     Also, when the wiper frame  70  is arranged to be inclined as described above, the connector  80  is formed to be inclined in the direction opposite to the inclination direction of the wiper frame  70  in order to couple the connector  80  with the wiper arm  15  ( FIG. 1 ). 
     In the meantime, the wiper frame  70  configured as described above is formed through a jig for heat treating a wiper frame to have a predetermined curvature by machining a wiper frame workpiece made of steel. 
       FIG. 8  is a plane view schematically showing a jig for heat treating a wiper frame according to the present invention. 
     As shown in  FIG. 8 , in a jig  200  for heat treating a wiper frame according to the present invention, a first jig  212  provided with a first working surface  213  having a predetermined curvature and a second jig  216  provided with a second working surface  217  having a predetermined curvature corresponding to the first working surface  213  are arranged opposite to each other at both ends of the jig  200 . 
     The first jig  212  and the second jig  216  are installed to a fixed forming frame  210  with a fixing means such as bolts or the like. Preferably, the first jig  212  is fixedly installed while the second jig  216  is moveably installed. Also, a pressing means  218  is installed to a lowerportion of the second jig  216  to press it to move the second jig  216 . 
     As described above, the heat treatment jig  200  to which a wiper frame workpiece  220  is mounted is fed to a heating furnace for annealing. Accordingly, in a state where the wiper frame workpiece  200  is bent to have an approximate curvature between the first jig  212  and the second jig  216 , the workpiece can be pressed and annealed at the same time. 
     Meanwhile, in order to improve the heat treatment performance of the heat treatment jig  200 , a heating means (not shown) may be provided in the first and second jigs  212  and  216  or the forming frame  210 . 
     A view showing a state where a plurality of wiper frames are machined in the jig heat treating a wiper frame according to the present invention is described with reference to  FIG. 9 . 
     First, the wiper frame workpiece  220 , which has been subjected to the heating and cooling processes to have elasticity, is bent to have an approximate curvature by means of an additional machining apparatus. 
     Next, the wiper frame workpiece  220  bent to have the approximate curvature is mounted to the jig  200  for heat treating a wiper frame. At this time, the wiper frame workpiece  220  is disposed between the first and second jigs  212  and  216 . Thereafter, in a state where the pressing means  218  is operated to cause the second jig  216  to press the wiper frame workpiece  220 , the heat treatment jig  200  feeds the wiper frame workpiece  220  to the heating furnace (not shown), and the wiper frame workpiece  220  is then annealed. 
     Meanwhile, in a state where upper and lower surfaces of the wiper frame workpiece  220  is respectively pressed by the first and second working surfaces  213  and  217  of the first and second jigs  212  and  216 , the wiper frame workpiece  220  is heated to an appropriate temperature to have a curvature which is the same as that of the first and second jigs  212  and  216  and to remove internal stress of the workpiece, thereby having a predetermined shape. 
     Accordingly, with the jig  220  for heat treating a wiper frame, the wiper frame workpiece  220  is formed to have a curvature corresponding to a specification of the article and to have a shape of the wiper frame. 
     In the meantime, in the jig  200  for heat treating a wiper frame, only one wiper frame workpiece  220  is put between the first jig  212  and the second jig  216  to be machined, or a plurality of wiper frame workpieces  220  can be put in a lump therebetween to be machined. To this end, as shown in  FIG. 10 , an auxiliary jig  230  may be installed between the plurality of wiper frame workpieces  220  so that the wiper frame workpieces have a desired curvature. 
       FIG. 10  is a view showing a state where a plurality of the wiper frames are machined in the jig for heat treating a wiper frame according to the present invention. In the jig  200  for heat treating a wiper frame, if the number of the wiper frame workpieces  220  to be simultaneously formed is increased, it is preferred that the auxiliary jigs  230  having a curvature corresponding to the first and second working surfaces  213  and  217  be disposed between the wiper frame workpieces  220 . 
     As described above, since the auxiliary jigs  230  are disposed between the wiper frame workpieces  220 , it is possible to reduce a curvature error occurring when the plurality of wiper frame workpieces  220  are simultaneously formed. 
     In addition, a method for manufacturing the wiper frame of the wiper blade  50  according to the present invention is as follows. 
     The wiper frame  70  of the wiper blade  50  according to the present invention is made of a steel material. The structure and strength of the wiper frame can be varied depending on conditions of heat treatment of the steel material, so that the formed configuration of the wiper frame can be maintained continuously. 
       FIG. 11  is a flow chart illustrating a method for manufacturing the wiper frame  70  of the wiper blade  50  according to the present invention. 
     As shown in  FIG. 11 , the method for manufacturing the wiper frame  70  of the wiper blade  50  according to the present invention comprises a heat treating step S 11  including a heating and cooling step, a blanking step S 14 , a piercing step S 15 , a bending step S 16 , and a heat treating and forming step S 17 . 
     The heat treating step S 11 , which is the step of heat treating a workpiece made of steel, comprises a heating step S 12  of heating the workpiece to a transformation temperature or more and a cooling step S 13  of rapidly cooling the workpiece heated in the heating step S 12 . If the workpiece is subjected to such steps, the structure of the workpiece is transformed into martensite. 
     The martensite obtained in the above process is a rigid structure which is formed when the transformation from austenite stable at high temperature to a structure composed of cementite and α-iron stable at room temperature is partially interrupted. Next, the blanking step S 14  is to blank the workpiece, which has been heat treated in the heat treating step, according to a shape of the article. The blanked workpiece is machined into a wiper frame workpiece. 
     Once the wiper frame workpiece is prepared as described above, the wiper frame workpiece is subjected to the piercing step. At this time, unnecessary portions are removed from the wiper frame workpiece through the piercing step S 15 , thereby forming the coupling slits and the coupling aperture. 
     Next, the bending step S 16  is to bend the wiper frame workpiece to have a predetermined curvature. In the step, the wiper frame workpiece is preformed by being bent through a separate tool to have an approximately bent shape. 
     Meanwhile, in the heat treating and forming step S 17 , the wiper frame workpiece is mounted to the jig for heat treating a wiper frame as described above. At this time, the wiper frame workpiece is mounted between the first and second jigs. The pressing means is operated to press the wiper frame workpiece, and at the same time, the heat treatment jig is fed into the heating furnace to anneal the wiper frame workpiece. 
     As described above, after being preformed in the bending step S 16 , the wiper frame workpiece is pressed by means of the first and second jigs and simultaneously annealed in the heat treating and forming step S 17 . Thus, the wiper frame workpiece is completely formed to have a desired curvature. At this time, when the wiper frame workpiece is subjected to the anneal process, the internal stress of the wiper frame workpiece increased in the bending step S 16  is relieved and the internal structure becomes uniform, thereby completing the finished product. 
     INDUSTRIAL APPLICABILITY 
     Although the present invention is described with respect to certain preferred embodiment, it will be apparent in the art can make that various modifications, variations and changes may be made thereto within the spirit and scope of the invention defined by the claims. Therefore, the above descriptions and appended drawings are not intended to limit the technical spirit of the present, invention but should be analyzed as the exemplifications of the present invention.