Abstract:
A tape rule with an improved structure at the end of metal tape. The tape hook is secured onto the end surface of metal tape by five rivets, and said rivets are arranged in a shape of English letter “T”, such that the security of tape and hook is enhanced.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to tape rules, especially to springpowered rewindable tape rules having an improved structure at the end of the tape, so as to enhance the reliability of tape rules.  
           [0003]    2. Description of the Prior Art  
           [0004]    The structure of the end of metal tape of conventional tape rules is shown in FIG. 1; at the end of the retractable metal tape  111 , two rivet holes  121 ,  122  aligned on the tape retraction direction are formed on the tape  11 ; a hook  13  formed by a bended metal plate is secured to the end of the tape  11 . Said book  13  includes a body portion  15  and a hook portion  14 ; on the body portion  15  of the hook  13 , two holes  161 ,  162  corresponding to said two rivent holes  121 ,  122  are formed. Two rivets  171 ,  172  are firstly respectively put into a pair of said rivet hole  121  ( 122 ) formned on the tape  11  and hole  161  ( 162 ) formed on the body portion  15  of the hook  13 , and then rivet to secure the hook  13  with the tape end firmly. However, since the retraction of metal tape into the casing of tape rule is stopped abruptly by the impact of the tape hook afainst the wall on the easing about the aperture formed in the casing for retraction and releasing of metal tapes. The hook  13  on the end of tape rule only can endure 3000˜4000 times&#39; impact force generated in tape retraction. Therefore, the hook  13  is always lost and the tape rule become invalid.  
         SUMMARY OF THE INVENTION  
         [0005]    It is an object of present invention to provide a tape rule with improved structure of tape end in which the impact endurance of tape hook is enhanced.  
           [0006]    It is also an object of present invention to provide a tape rule with improved structure of tape end in which the duration of tape rule is increased.  
           [0007]    According to the tape rule with improved structure of tape end of present invention, the possibility of lost of tape hook is reduced and then the practicality of tape rule is also increased.  
           [0008]    A more complete understanding of these and other features and advantages of the present invention will become apparent from a careful consideration of the following detailed description of certain embodiments illustrated in the following drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 shows the structure of tape end conventional tape rules.  
         [0010]    [0010]FIG. 2 shows the structure of tape end of the tape rule of present invention.  
         [0011]    [0011]FIG. 3 is a cross-sectional view showing the construction of rivets with tape hook and metal tape. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    Referring to FIG. 2, the metal tape  21  of the tape rule  20  of present invention has five small holes  221 ,  222 ,  223 ,  224 ,  225  formed at the end of the metal tape  21 ; said five small holes are aligned both in longitudinal and perpendicular directions, such that said five small holes are arranged in “T” shape with each alignment having three small holes. A tape hook  23  is secured to the end of the metal tape  21 ; it also includes a body portion  231  and a hook portion  231  bended downward to the body portion  232 . On the body portion  232  of the tape hook  23 , there are five rivet holes  241 ,  242 ,  243 ,  244   245  corresponding and opposing to said five small holes  221 ,  222 ,  223 ,  224 ,  225  formed at the end of the metal tape  21 . The widths of both body portion  232  and hook portion  231  of tape hook  23  are preferably not larger than that of metal tape  21 , and the body portion  232  of tape hook  23  is preferably formed in T shape to match with the alignment of above-mentioned five small holes  221 ,  222 ,  223 ,  224 ,  225  formed at the end of the metal tape  21  and the five rivet holes  241 ,  242 ,  243 ,  244 ,  245  formed on the body portion  232  of the tape hook  23 . Said tape hook  23  is secured to the metal tape  21  by passing the stem portions  251 A,  252 A,  253 A,  254 A,  255 A of rivets  251 ,  252 ,  253 ,  254 ,  255  respectively through a pair of holes containing a small holes  221 ,  222 ,  223 ,  224 ,  225  rivets holes  241 ,  242 ,  243 ,  244 ,  245  mentioned above, and pressing the end of the stem portions  251 A,  252 A,  253 A,  254 A,  255 A of said rivets  251 ,  252 ,  253 ,  254 ,  255  to form open rings  251 C,  252 C,  253 C,  254 C,  255 C attached to the lower rim of said small holes  221 ,  222 ,  223 ,  224 ,  225  (as shown in FIG. 3).  
         [0013]    Since the tape hook  23  is secured to the end of the metal tape  21  by five rivets  251 ,  252 ,  253 ,  254 ,  255  and the five rivets  251 ,  252 ,  253 ,  254 ,  255  aligned as a T shape character, that is, three rivets  251 ,  252 ,  253  are aligned in horizontal direction and three rivets  251 ,  254 ,  255  are aligned in longitudinal direction. Then, the tape hook  23  would secured much more firmly to the metal tape  21 . The shearing strain between the tape hook  23  and the metal tape  21  generated due to the longitudinal impact force of hook portion  231  against the outer wall of casing about the tape retraction aperture would be distributed by said five rivets  251 ,  252 ,  253 ,  254 ,  255  preferably by three longitudinal three rivets  251 ,  254 ,  255 , and then reduced; the torque which is generated during the time when the metal tape is retracted also would be distributed by said five rivets  251 ,  252 ,  253 ,  254 ,  255 , preferably by the horizontal three rivets  251 ,  252 ,  253 , and then reduced. The impact endurance of present invention would be increased to as three times of conventional tape rules.  
         [0014]    Although the present invention has been described with a certain degree of particularity by six examples, the present disclosure has been made by way of example and changes in details of structure may be made without departing from the spirit thereof.