Patent Publication Number: US-2011058890-A1

Title: Tip for Ball Point Pen

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2009-0084983 filed in the Korean Intellectual Property Office on Sep. 9, 2009, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a tip for a ball point pen. More particularly, the present invention relates to a tip for a ball point pen that makes it possible to increase the outflow amount of ink and implement more comfortable writing by smoothly forming the external circumferential surface of the end where a ball support is formed. 
     (b) Description of the Related Art 
     In general, ball point pens are writing materials that write in a way of smearing ink on a ball rotated by friction with a writing surface, such as paper, and transferring the ink on the paper, and have a tip for the ball point pen. 
     As shown in  FIG. 1  and  FIG. 2 , a tip  1  for a ball point pen is composed of a tip body  2  and a ball  10  positioned at the front end of the tip body  2 , in which the tip body  2  has an ink outflow channel  3  and a ball house  4  retaining the ball  10  to be partially exposed, at the end of the ink outflow channel  3 . 
     The front end portion of the tip body  2  of the tip  1  for a ball point pen is formed in a conical shape with an external circumferential slope  5  at about 30 to 60°. A ball support  6  that supports the ball is formed by spinning or caulking to make the front end narrower, with the ball  10  in the ball house  4 . 
     According to the tip  1  for a ball point pen, as the ball  10  is moved backward by pressure applied in writing, the gap between the ball  10  and the ball support  6  is made wider, such that ink flows out. 
     However, in the tip  1  for a ball point pen of the related art, the height ‘h’ of the exposed portion of the ball  10  and convenience of manufacturing are considered in priority in making the ball support  6  in the tip body  2 ; however, outflow performance of the ink is generally not considered. 
     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 
     The present invention has been made in an effort to provide a tip for a ball point pen having advantages of making it possible to implement more comfortable writing by making the external circumferential slope smooth to form a ball support and effectively increasing the outflow amount of ink with the increase of a ball displacement. 
     An exemplary embodiment of the present invention provides a tip for a ball point pen, which includes: a spherical ball; and a tip body having the front end formed in a conical shape, a ball house formed at the end of an ink outflow channel, and a ball support formed by making the front end portion narrower such that the ball is partially exposed and supported in the ball house. 
     The external circumferential surface for forming the ball support of the tip body is formed at a taper angle of 3 to 10°. 
     According to the exemplary embodiment of the present invention, it is possible to increase the outflow amount of ink discharged through between the ball and the inner side of the ball support in writing, because the front-rear displacement of the ball increases after the ball support is formed, when the external circumferential surface of the tip body is formed at a predetermined range of a taper angle to form the ball support. 
     Therefore, it is possible to implement more comfortable writing while achieving smooth writing, as compared with the related art. 
     Further, according to the exemplary embodiment of the present invention, since the gap between the ball and the inner side of the ball support increases in writing, it is possible to reduce the amount of ink that does not flow into the ball support and collects outside. 
     Therefore, it is possible to prevent a writing line, a writing surface, and hands etc from being stained with the collecting ink, and it is also possible to write and keep the pen while keeping it clean. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing a tip for a ball point pen of the related art; 
         FIG. 2  is an enlarged cross-sectional view showing the tip for a ball point pen of the related art; 
         FIG. 3  is an enlarged cross-sectional view showing when a ball support is not formed yet in a tip for a ball point pen according to an exemplary embodiment of the present invention; and 
         FIG. 4  is an enlarged cross-sectional view showing when a ball support is formed in the tip for a ball point pen according to an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. 
     First, a tip for a ball point pen according to an exemplary embodiment of the present invention, as shown in  FIGS. 1 to 3 , includes a ball  101  and a tip body  110  with the ball  101  at the front end. 
     The ball  101  is a sphere having a predetermined diameter. 
     The diameter of the ball  101  may be about 0.3 to 1.2 mm. 
     The front end portion of the tip body  110  is formed in a conical shape and the rear end portion is assembled with an ink storage pipe  20 . 
     An ink outflow channel  111  is formed through the tip body  110  along the center axis line C to supply the ink stored in the ink storage pipe  20  to the ball  101 . 
     A ball house  112  retaining the ball  101  is formed at the front end portion of the ink outflow channel  111  of the tip body  110 . 
     The ball  101  is retained, with a portion exposed, in the ball house  112 . 
     A ball support  115  is formed by spinning (or caulking) at the front end portion  114  of the tip body  110 . 
     The front end portion  114  for forming the ball support  115  has an external diameter gradually increasing toward the rear such that the angle ‘a’ (hereafter, referred to as a “taper angle”) made by the external circumferential slope and the center axis line C is about 3 to 10°. 
     That is, the external circumferential surface of the front end portion  114  has a taper angle ‘a’ of about 3 to 10° before the ball support  115  is formed. 
     The following Table 1 shows an experiment result for examining changes in the amount of ink Q (hereafter, referred to as ‘ink outflow amount) discharged through between the ball  101  and the inner side of the ball support  115  in writing in accordance with the taper angle ‘a’ of the front end portion  114 , which measured the front-rear displacement ‘d’ of the ball  101  and the ink outflow amount Q while changing the taper angle ‘a’ and the spinning width ‘b’ and maintaining the ball height h 1  before the ball support  115  is formed and the ball height h 2  after the ball support  115  is formed. 
     The ball  101  was 0.7 mm and the tip body  110  was 0.7 mm hybrid test  14 , and the ink was JSRB 2, and spinning is performed to the ball support  115  at 2520 rpm. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Condition 
                 Result 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Order 
                 a(°) 
                 h1 (mm) 
                 h2 (mm) 
                 B (mm) 
                 D (mm) 
                 Q (mg/100M) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 17 
                 0.235 
                 0.215 
                 0.230 
                 0.010 
                 20 
               
               
                 2 
                 15 
                 0.235 
                 0.215 
                 0.200 
                 0.010 
                 24 
               
               
                 3 
                 12 
                 0.235 
                 0.215 
                 0.166 
                 0.012 
                 28 
               
               
                 4 
                 9 
                 0.235 
                 0.215 
                 0.143 
                 0.014 
                 32 
               
               
                 5 
                 6 
                 0.235 
                 0.215 
                 0.126 
                 0.016 
                 38 
               
               
                 6 
                 3 
                 0.235 
                 0.215 
                 0.113 
                 0.018 
                 42 
               
               
                 7 
                 0 
                 0.235 
                 0.215 
                 0.104 
                 0.020 
                 48 
               
               
                   
               
            
           
         
       
     
     As can be seen from Table 1, it was shown that the larger the taper angle ‘a’, the more the front-rear displacement ‘d’ of the ball  101  and the ink outflow amount Q substantially decrease, whereas the smaller the taper angle ‘a’ the more the front-rear displacement ‘d’ of the ball  101  and the ink outflow amount Q increase. 
     Meanwhile, it is difficult to perform spinning to the front end portion of the tip body  110 , when the taper angle ‘a’ is small, below 3°, while the front-rear displacement ‘d’ of the ball  101  does not increase, when the taper angle ‘a’ is substantially above 10°; therefore, it would be preferable not to select these cases. 
     While the present 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.