Patent Publication Number: US-2005120834-A1

Title: Ratchet wrench

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a hand tool, and more particularly to a ratchet wrench which is easy in assembly.  
      2. Description of the Related Art  
      A conventional ratchet wrench consists of a handle, a ratchet wheel and a pawl. The handle is provided with a hole at an end thereof for accommodating the ratchet and the pawl therein. On a sidewall of the hole has an annular recess, in which a C-ring is mounted to secure the ratchet and the pawl.  
      Basically, it is complicated in processing the annular recess on the sidewall of the hole of the handle. It needs a specific machine tool to mill the recess. It also needs pointed pliers to mount the C-ring in the recess. The C-ring makes variations for fabrication and makes more difficult for assembly.  
      An earlier invention, i.e. U.S. Pat. No. 6,591,718, of the present inventor provides a ratchet wrench, which is easier to assembly than the above-mentioned conventional ratchet wrench. The present invention is another design of the present inventor to provide a ratchet wrench which also has functions of reducing cost, increasing the efficiency of fabrication and reducing the proportion of defective.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a ratchet wrench, which is easier for assembly and fabrication so as to reduce the cost of fabrication.  
      The secondary objective of the present invention is to provide a ratchet wrench, which works stably.  
      To achieve aforesaid objectives of the present invention, a ratchet wrench comprises a handle having a hole for accommodating a ratchet wheel and a pawl therein. The ratchet has a first teeth portion detachably meshed with a second teeth portion of the pawl. The ratchet wheel is rotatably mounted in the hole of the handle and has two engagement portions oppositely protruded out of the hole of the handle. Two annular members are respectively fastened to the engagement portions of the ratchet wheel. Each of the annular members has an outer diameter greater than a diameter of the hole of the handle.  
      The annular members are preferably fastened to engagement portions of the ratchet wheel by an interfere fit respectively, and the engagement portions and annular members are provided with an embossment respectively at where they are fitted to each other in order to enhance the connection strength therebetween. The annular members can also be fastened to engagement portions of the ratchet wheel by screw threads.  
      In additional, one of the annular members is preferably integrally formed on the ratchet wheel as an annular flange at an end of the ratchet wheel directly.  
      The annular members are preferably made of a plastic material for reduction of the cost of fabrication. The plastic annular member also has a lighter weight and a superior flexibility. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded view of a first preferred embodiment of the present invention;  
       FIG. 2  is a perspective view of the first preferred embodiment of the present invention;  
       FIG. 3  is an enlarge sectional view of a part of the first preferred embodiment of the present invention;  
       FIG. 4  is an exploded view of a second preferred embodiment of the present invention;  
       FIG. 5  is a partial sectional view of a third preferred embodiment of the present invention, and  
       FIG. 6  is an exploded view of a fourth preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Please refer to FIGS. from  FIG. 1  to  FIG. 3 , a ratchet wrench  10  of the first preferred embodiment of the present invention mainly comprises a handle  20 , a ratchet wheel  30 , a pawl  40  and two annular members  50 .  
      The handle  20  is provided with a hole  21  at an end thereof and an open wrench portion  22  at the other end thereof.  
      The ratchet wheel  30  is mounted in the hole  21  of the handle  20  for free rotation. The ratchet wheel  20  has a polygonal hole  31  at a center for engagement with a nut, a bolt and the like. The ratchet wheel  30  is provided with a first teeth portion  32  at an annular outer surface thereof and two engagement portions  33  at opposite sides of the first teeth portion  31 , wherein the engagement portions  32  protrude out of the hole  21  of the handle  20  and are provided with an embossment  34  respectively on outer surfaces thereof. The engagement portions  32  are tube-like elements and are integrally formed on the ratchet wheel  30 .  
      The pawl  40  is mounted in the hole  21  of the handle  20  beside the ratchet wheel  30 . The pawl  40  has a second teeth portion  41  to be detachably mashed with the first teeth portion  32  of the ratchet wheel  30 . A spring  42  is mounted in the hole  21  of the handle  20  to push the pawl  40  laterally. The pawl  40  and the spring  42  are conventional elements, so they need not to be described in detail here.  
      The annular members  50  each have a hole  51  respectively. Diameters of the holes  51  are substantially equal to outer diameters of the engagement portions  33  of the ratchet wheel  30  respectively. The annular members  50  each have an outer diameter greater than a diameter of the hole  21  of the handle  20 . The annular members  50  are provided with an embossment portion  52  respectively on sidewalls of the holes  51 . The annular members  50  are press-fitted to the engagement portions  32  of the ratchet wheel  30  in interfere fit so that the ratchet wheel  30 , the pawl  40  and the spring  42  are mounted in the hole  21  of the handle  20  quickly.  
      The annular members  50  can be made of a metal material or a plastic material and on outer surfaces of which are provided with an embossment portion  53  respectively. The embossment portions  53  of the annular members  50  make the user easier to grip them.  
      The way of assembling the ratchet wrench  10  of the present invention is very easy. It only needs to press the annular members  50  onto the engagement portions  32  of the ratchet wheel  30  respectively after the ratchet wheel  30 , the pawl  40  and the spring  42  are mounted in the hole  21  of the handle  20 . It also reduces the proportion of defective.  
       FIG. 4  shows a ratchet wrench  60  of the second preferred embodiment of the present invention, which is similar to the ratchet wrench  10  of the first preferred embodiment, having a handle  61 , a ratchet wheel  62  having two engagement portions  65 , a pawl  63  and two annular members  64 . The engagement portions  65  of ratchet wheel  62  and the annular members  64  are provided with a thread  66  or  67  respectively so that the annular members  64  are mounted to the engagement portions  65  of ratchet wheel  62  by screwing.  
       FIG. 5  shows a ratchet wrench  70  of the third preferred embodiment of the present invention, wherein engagement portions  71  of a ratchet wheel  70  and annular members  72  are provided with a slope surface  71 A or  72 A respectively. The slope surfaces  71 A and  72 A, which are matched with each other, make the annular members  72  not escaping from the engagement portions  71  of the ratchet wheel  70 .  
      It has to be mentioned that the ways of how to mount the annular members on the engagement portions of the ratchet wheel are various and they are not the main scope of the present invention and should not be only limited in the structures shown in the preferred embodiments. Any structure of making the annular members mounted on the engagement portions of the ratchet wheel stably will be within the scope of the present invention.  
       FIG. 6  shows a ratchet wrench  80  of the fourth preferred embodiment of the present invention having a handle  81 , a ratchet wheel  82 , a pawl  83  and an annular member  84 , wherein the ratchet wheel  82  is provided with an annular flange  85  at an end thereof and an engagement portion  86  at the other end thereof. The annular flange  85  has an outer diameter greater than a diameter of the hole of the handle where the ratchet wheel  82  and the pawl  83  are mounted therein.  
      In conclusion, the present invention provides the annular members mounted to the engagement portions of the ratchet wheel that make the ratchet wrench can be assembled quickly. In additional, the cost of fabrication is reduced therefore and the ratchet wrench works stably.