Patent Publication Number: US-2006000316-A1

Title: Wrench with socket engaged by coupling shaft protruded from wrench body

Description:
The present invention is a continuation in part of U.S. patent application Ser. No. 10/300,376, assigned and invented to the inventor of the present invention. Therefore the content of the invention 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 wrenches, and particularly to an engaging device of a sleeve-form wrench.  
      2. Description of Related Art  
      Referring to  FIGS. 1 and 2 , the coupling shafts of prior art wrenches are illustrated. The prior art coupling shafts have rectangular shapes or hexagonal shapes. The surfaces of the coupling shafts are plane surfaces. In general, the coupling shaft and sleeve can not be well engaged and thus the twisting force can not be concentrated and unwanted friction occurs (referring to  FIG. 3 ).  
      To improve the defect of the prior art, referring to  FIGS. 4 and 5 , a third prior art is illustrated. A buckle is formed on the periphery of a coupling shaft and an inner surface of the sleeve is formed with a corresponding structure so that the sleeve and coupling shaft are engaged more firmly. However, the twisting force can not be well transferred to an object to be rotated and the stress is concentrated at some places.  
      With reference to  FIG. 6 , it is illustrated that a prior art coupling shaft is coupled to a sleeve. It is shown that the coupling between the two has a 90 degree structure, as indicated in b. When the spanner twists the sleeve to drive the nut, the transfer of twisting force will disperse because the stress is concentrated on some points. For a long time, gaps will generate these points.  
      Referring to  FIGS. 7 and 8 , another prior art is shown. In this embodiment, the engagement of the sleeve and coupling shaft is similar to that of above embodiment. For example, as shown in  FIG. 8 , the convex portions of the coupling shaft has a flat surface and the concave portions have a concave shape. Thereby the connection of the convex portion and the concave portion is formed with an angle near 90 degrees, as c point indicated in  FIG. 9 . Thereby, not only when the sleeve is taken down, the rubber ring will drop out, but also the twisting force can not be well transferred. As a result these prior arts are necessary to be improved.  
     SUMMARY OF THE INVENTION  
      Accordingly, the primary object of the present invention is to provide an engaging device of a sleeve-form wrench comprising a spanner body and a sleeve. On an outer peripheral surface of the coupling shaft, a plurality of convex buckling portions and concave surface portions are arranged along an axial periphery of the coupling shaft; the convex buckling portions and concave surface portions have cambered shapes and are connected one by one; an inner wall of the sleeve is formed with concave arc portions with respect to the convex buckling portions and convex arc portions with respect to the concave surface portion so that the coupling shaft are inserted thereinto. By above structure, the spanner body and the sleeve are combined tightly; moreover, the sleeve suffers a larger twisting force from the spanner body and the stress distributes uniformly.  
      The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded schematic view of a first prior art.  
       FIG. 2  is an exploded perspective view of a second prior art.  
       FIG. 3  is a cross section view showing one operation of the second prior art.  
       FIG. 4  is an exploded perspective view of a third prior art.  
       FIG. 5  shows another embodiment of the third prior art.  
       FIG. 6  is an assembled schematic cross sectional view of the third prior art.  
       FIG. 7  is an exploded schematic view of a fourth prior art.  
       FIG. 8  is an exploded perspective view of a fifth prior art.  
       FIG. 9  is a schematic view showing that a rubber ring is installed in the fifth prior art.  
       FIG. 10  is a schematic view of the present invention.  
       FIG. 11  is an exploded schematic view of the present invention.  
       FIG. 12  is a schematic cross sectional view of the present invention.  
       FIG. 13  is a schematic view of another embodiment of the present inrtvcntion. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to FIGS.  10  to  12 , the engaging device of a sleeve-form wrench of the present invention is illustrated. The engaging device of a sleeve-form wrench includes a spanner body  10  and a sleeve  20 . One end of the spanner body  10  with respect to the handle  11  is formed with a head portion  12 . The head portion  12  is installed with a ratchet element (not shown). A coupling shaft  30  is protruded from the head portion  12  for being engaged with a sleeve  20 . A tightening element  40  encloses the coupling shaft  30 .  
      On an outer peripheral surface of the coupling shaft  30 , a plurality of convex buckling portions  31  and concave surface portions  32  are arranged along the axial periphery of the coupling shaft  30 . The convex buckling portions  31  and concave surface portions  32  have cambered shapes and are connected one by one. A notch  33  is formed along the axial periphery of the coupling shaft  30  for being enclosed by a tightening element  40 .  
      The sleeve  20  is a prior art sleeve. The inner wall of the sleeve  20  is formed with concave arc portions  21  with respect to the convex buckling portions  31  and convex arc portions  22  with respect to the concave surface portion  32  so that the coupling shaft  30  can be inserted thereinto. The sleeve  20  is formed with a groove  23  in the inner surface thereof.  
      The tightening element  40  has a configuration corresponding to that of the coupling shaft  30  and thus has convex portions  41  and concave portions  42 . When the tightening element  40  is engaged with the coupling shaft  30 , the tightening element  40  is exactly buck led to the notch  33  and slightly protruded from the surface of the coupling shaft  30 . The engagement of the tightening element  40  and the coupling shaft  30  are tightly so that no gap is formed therebetween.  
      Thereby, by above structure, the spanner body  10  and the sleeve  20  are combined tightly. Moreover, the sleeve can suffer a larger twisting force from the spanner body and the stress will not concentrate at some places. Referring to  FIG. 13 , the tightening element  40  on the coupling shaft  30  can be used to a round coupling shaft  30 .  
      In one embodiment of the present invention, there are six convex buckling portions and six concave surface portions.  
      Moreover referring to  FIG. 11  of the present invention, a middle section of the handle  11  has a plurality of annular recesses. Thereby the user can hole the handle firmly.  
      The advantages of the present invention will be described hereinafter:  
      1. Since the tightening element  40  is engaged to and completely adhered to the coupling shaft  30 , when the coupling shaft  30  is coupled to the sleeve  20 , not only the tightening element  40  will not drop out, but also the coupling shaft  30  and sleeve  20  are tightly coupled.  
      2. Since the convex buckling portion  31  and concave surface portion  32  of the coupling shaft  30  are connected one by one, and the concave arc portion  21  and convex arc portion  22  of the sleeve  20  are connected one by one. The stress induced from twisting an object will not corecentrate at some critical points so that the strength of the spanner is improved.  
      Although the present invention has been described with reference to the preferred embodiments, it will be understood that the invention is not limited to the details described thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.