Patent Publication Number: US-2006005671-A1

Title: Screwdriver having larger driving force

Description:
The present invention is a continuation in part (CIP) of the U.S. Patent Application with Series Number of 10/638931 assigned and invented by the inventor and applicant of the present invention. Thus, the content of U.S. patent application with Ser. No. of 10/638,931 is incorporated into the present invention as a part of the present invention. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a screwdriver, and more particularly to a screwdriver having a larger driving force and torque.  
      2. Description of the Related Art  
      A conventional screwdriver  40  in accordance with the prior art shown in  FIGS. 5 and 6  comprises a flat tip  42  inserted into the groove  52  of a screw  50 . When the screwdriver  40  is rotated relative to the screw  50 , only two points  44  and  46  of the tip  42  of the screwdriver  40  are in contact with the wall of the groove  52  of the screw  50 , thereby decreasing the driving force of the screwdriver  40  applied on the screw  50 . In addition, only two points  44  and  46  of the tip  42  of the screwdriver  40  are in contact with the wall of the groove  52  of the screw  50 , so that the wall of the groove  52  of the screw  50  is easily Worn out due to a stress concentration.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a screwdriver having a larger driving force and torque.  
      Another objective of the present invention is to provide a screwdriver, wherein by provision of the auxiliary resting portion of the tip, the first resting portion and the second resting portion are slightly bent and deformed and are entirely flush with the wall of the groove of the screw to increase the contact area between the tip and the wall of the groove of the screw, so that the tip of the screwdriver can apply a larger driving force to drive the screw, thereby facilitating the user rotating the screw.  
      A further objective of the present invention is to provide a screwdriver, wherein the first resting portion and the second resting portion are entirely flush with the wall of the groove of the screw respectively, so that the contact area between the tip of the screwdriver and the wall of the groove of the screw is largely increased, thereby preventing the tip of the screwdriver from being worn out due to a stress concentration.  
      A further objective of the present invention is to provide a screwdriver, wherein the tip of the screwdriver is closely combined with the wall of the groove of the screw rigidly and stably, thereby preventing the wall of the groove of the screw from being worn out due to an excessive force.  
      In accordance with the present invention, there is provided A screwdriver comprises a tip having a substantially I-shaped cross-section comprising: a first end formed with a first resting portion, a second end formed with a second resting portion, and a mediate section formed with an auxiliary resting portion located between the first resting portion and the second resting portion; A width between two larger sides of the auxiliary resting portion is 0.3 to 0.5 times of that of the first resting portion and that of the second resting portion. A length between two shorter sides of the auxiliary resting portion is 0.3 to 0.5 times of a length connected two shorter sides of the tip. The first resting portion and the second resting portion of the tip are bent and deformed when being subjected to a torque.  
      Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a screwdriver in accordance with the preferred embodiment of the present invention;  
       FIG. 2  is a partially enlarged view of the screwdriver as shown in  FIG. 1 ;  
       FIG. 3  is a side plan cross-sectional assembly view of the screwdriver and a screw;  
       FIG. 4  is a schematic operational view of the screwdriver and the screw as shown in  FIG. 3 ;  
       FIG. 5  is a side plan cross-sectional assembly view of a conventional screwdriver and a screw in accordance with the prior art; and  
       FIG. 6  is a schematic operational view of the conventional screwdriver and the screw as shown in  FIG. 5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to the drawings and initially to  FIGS. 1-3 , a screwdriver  10  in accordance with the preferred embodiment of the present invention comprises a shank  14 , a handle  12  mounted on a first end of the shank  14 , and a flat tip  16  mounted on a second end of the shank  14 .  
      The tip  16  has a substantially I-shaped cross-section and has a first end formed with a first resting portion  18 , a second end formed with a second resting portion  20 , and a mediate section formed with an auxiliary resting portion  22  located between the first resting portion  18  and the second resting portion  20 .  
      Preferably, each of the first resting portion  18  and the second resting portion  20  has a substantially rectangular cross-section.  
      Preferably, the auxiliary resting portion  22  of the tip  16  is integrally connected between the first resting portion  18  and the second resting portion  20 . Preferably, the auxiliary resting portion  22  of the tip  16  has a thickness smaller than that of each of the first resting portion  18  and the second resting portion  20 , so that the auxiliary resting portion  22  of the tip  16  can be deformed when the first resting portion  18  and the second resting portion  20  are subjected to a rotational torque. Preferably, the auxiliary resting portion  22  of the tip  16  has a top and a bottom each formed with a depression  220  to enhance flexibility of the auxiliary resting portion  22  of the tip  16 , thereby facilitating deformation of the auxiliary resting portion  22  of the tip  16 .  
      Furthermore, at an end of the tip of the screwdriver, all the sides of the first and second resting portions  18 ,  20  and the auxiliary resting portion  22  are straight and all the corners formed by the connections of the first resting portion  18 , the auxiliary resting portion  22  and the second resting portion  20  are approximate right angles; and an end surface of the first resting portion  18 , an end surface of the auxiliary resting portion  22 , and an end surface of the second resting portion  20  are at the same plane.  
      Referring to  FIG. 2 , a width between two larger sides of the auxiliary resting portion  22  is 0.3 to 0.5 times of that of the first resting portion  18  and that of the second resting portion  20 . A length between two shorter sides of the auxiliary resting portion  22  is 0.3 to 0.5 times of a length connected two shorter sides of the tip  16 .  
      In operation, referring to  FIGS. 3 and 4  with reference to  FIGS. 1 and 2 , the tip  16  is inserted into the groove  32  of a screw  30  as shown in  FIG. 3 . When the screwdriver  10  is rotated relative to the screw  30 , the tip  16  is rotated and moved from the position as shown in  FIG. 3  to the position as shown in  FIG. 4 , so that the first resting portion  18  and the second resting portion  20  are subjected to a torque exerted by the wall of the groove  32  of the screw  30 . At this time, the auxiliary resting portion  22  of the tip  16  is slightly deformed when the first resting portion  18  and the second resting portion  20  are subjected to the torque, so that the first resting portion  18  and the second resting portion  20  are slightly bent and deformed and are entirely flush with the wall of the groove  32  of the screw  30  respectively, thereby greatly increasing the contact area between the first resting portion  18  and the second resting portion  20  and the wall of the groove  32  of the screw  30 .  
      Thus, the tip  16  of the screwdriver  10  is combined with the wall of the groove  32  of the screw  30  rigidly and stably, so that the tip  16  of the screwdriver  10  can apply a larger driving force to drive the screw  30 .  
      Accordingly, by provision of the auxiliary resting portion  22  of the tip  16 , the first resting portion  18  and the second resting portion  20  are slightly bent and deformed and are entirely flush with the wall of the groove  32  of the screw  30  respectively to increase the contact area between the tip  16  and the wall of the groove  32  of the screw  30 , so that the tip  16  of the screwdriver  10  can apply a larger driving force to drive the screw  30 , thereby facilitating the user rotating the screw  30 .  
      In addition, the first resting portion  18  and the second resting portion  20  are entirely flush with the wall of the groove  32  of the screw  30  respectively, so that the contact area between the tip  16  of the screwdriver  10  and the wall of the groove  32  of the screw  30  is largely increased, thereby preventing the tip  16  of the screwdriver  10  from being worn out due to a stress concentration.  
      Further, the tip  16  of the screwdriver  10  is closely combined with the wall of the groove  32  of the screw  30  rigidly and stably, thereby preventing the wall of the groove  32  of the screw  30  from being worn out due to an excessive force.  
      Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.