Patent Publication Number: US-2007101833-A1

Title: Ratchet tool

Description:
FIELD OF THE INVENTION  
      The present invention relates to ratchet tools, more particularly to a ratchet tool that is easy to assemble and can produce louder noises for a better recognition of a user.  
     BACKGROUND OF THE INVENTION  
      A ratchet tool of the prior art, as disclosed by U.S. Pat. No. 6,386,072, uses a switch to drive the left and right shift of a driving piece, which in turn drives a resilient pushing device to push a braking piece to engage another driving piece, whereby the wrench box can attain a forward and backward rotation. Further, a longitudinal supporting device within the wrench main body can be engaged with a locking portion of the driving piece to achieve a retaining effect of a ratchet wheel.  
      However, the ratchet wrench of the prior art lacks a basic function of producing noises in backward reposition for facilitating operation in the night time when visual recognition is not allowed.  
      In a conventional ratchet wrench, the braking piece is driven by the pushing unit disposed in the half-moon shaped rear portion of the retaining box of a ratchet wrench, which pushing unit consists of a resilient piece and a pushing piece and provide the reposition of the braking piece with a necessary force. Thereby, the driving part and the switch unit can be engaged, and, since a locking portion of the switch unit restricts the motion of the switch unit, the driving part of the wrench is accordingly locked, leading to a small spacing between a projected portion and a groove of the driving part for the braking piece to move. Therefore, the noises produced in a process of backward reposition are not loud enough for people operating it at night time hard to recognize such a reposition.  
      Further, a ratchet wrench of the prior art has a complex assembly process that includes a step of locking a buckle body within boundary groove around a cover, in addition to an orderly placement of the driving part and the braking body.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a ratchet tool wherein a braking piece urged by a multi-step repositioning spring force in a *process of backward reposition will produce louder noises for a better recognition of a user.  
      The secondary objective of the present invention is to provide a ratchet tool capable of being easily sealed by a cover plate and assembled fast.  
      To achieve above object, present invention provides a ratchet tool. The ratchet tool comprises a wrench handle forming at least a box head at one end thereof, said box head having a first and a second receptacle areas which are connected, said first receptacle area being provided with a flange and an annular groove; a ratchet wheel engaged with said an annular groove of said box head and rotationally confined in said first receptacle area; a cover plate connecting said wrench handle and said ratchet wheel, one side of said cover plate being provided with a through hole for passing said ratchet wheel, another side of said cover plate being provided with an arched hole corresponding to said second receptacle area; a braking piece having a front arched surface provided with a teeth portion corresponding to said outer ratchet teeth of said ratchet wheel and a rear surface provided with a pair of lateral contact faces supported against said second receptacle area, a top surface of said braking piece further including a pair of blocking parts for facilitating changing directions of said braking piece, the motion of said braking piece being restricted in said arched through hole of said cover plate, a front surface of said braking piece being provided with a teeth portion capable of being engaged with outer ratchet teeth around said ratchet wheel by a first pushing unit; a connecting piece disposed beneath said cover plate having a blocking piece extended from a top surface thereof, said blocking piece being connected to said connecting piece through a flexible unit; and a switch piece locked with said connecting piece and being capable of being switched in a direction selected from left and right directions.  
      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 drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded perspective view of a ratchet tool of the present invention.  
       FIG. 1A  is a local cross-sectional view of the ratchet tool in  FIG. 1 .  
       FIG. 1B  shows the bottom end of the ratchet wheel of the ratchet tool in  FIG. 1 .  
       FIG. 2  show the assembly of the ratchet wheel of the ratchet tool in  FIG. 1 .  
       FIG. 3  is a local perspective view of the ratchet tool in  FIG. 1 , after the assembly.  
       FIG. 4  is a local cross-sectional view of the box head of the ratchet tool in  FIG. 1 .  
       FIG. 5  is a local perspective view of the ratchet tool in  FIG. 1  wherein the switch is pointed to a clockwise direction.  
       FIG. 6  is a local cross-sectional view of the braking piece of the ratchet tool in  FIG. 1  when the wrench handle is twisted in a counterclockwise direction and it is tilted against a receptacle area.  
       FIG. 7  is a local cross-sectional view showing the braking piece being pushed by the ratchet wheel in a process backward reposition.  
       FIG. 8  illustrates the angle between the connecting piece and the horizontal connecting beam of the ratchet tool in  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1, 1A  and  4 , a ratchet tool according to the present invention comprises a bench handle  10 , a ratchet wheel  20 , a cover plate  30 , a braking piece  40 , a T shaped connecting piece and a switch piece  60 .  
      The wrench handle  10  is basically a handle with at least one closed box head  11  at one end thereof. The box head  11  has a round first receptacle area  12  whose axis extends along the axial direction of the box head  11 . One lateral side of the first receptacle area  12  forms a half-moon shaped second receptacle area  13 . The lower rim of the first receptacle area  12  is provided with a flange  121 , and the upper rim of the first receptacle area  12  is provided with an annular groove  122 .  
      The ratchet wheel  20 , retained in a rotatable fashion in the first receptacle area  12 , has a polygonal inner wall  21  and an outer wall on which a multitude of ratchet teeth  22  are uniformly arranged. The inner wall  21  and the outer wall  22  is separated by a flange wall  23 .  
      The cover plate  30  is retained on the ratchet wheel  20  by the engagement between the flange wall  23  and a through hole  31  thereon. The cover plate  30  is further coupled to the annular groove  122  around the first receptacle area  12 , as so to prevent the cover plate  30  from a departure from the first receptacle area  12 . On later side of the cover plate  30  is extended with a half-moon shaped projected area that corresponds to the second receptacle area  13 . The projected area is further provided with an arched hole  32  and a connected slot  33 , whereby the cover plate  30  can resiliently contract inward and can coupled to the annular groove  122  around the first receptacle area  12 .  
      The braking piece  40 , being an arched piece within the second receptacle area  13 , has a front arched surface provided with a plurality of teeth  41  corresponding to the outer ratchet teeth  22  around the ratchet wheel  20  and a rear arched surface that can be pushed by a spring A and a support steel ball B, whereby the front teeth  41  of the braking piece  40  can urged to engage the ratchet teeth  22  around the ratchet wheel  20 . The spring A and the support steel ball B form a first push mechanism and are disposed in a through hole  14  on the second receptacle area  13 . The lateral sides of the rear arched surface of the braking piece  40  respectively form support faces for engaging the inner wall of the second receptacle area  13 . Further, near the lateral sides of the braking piece  40 , there are vertically extended symmetrical retaining parts  42 , which retaining parts  42  are respectively further extended with horizontal extended rods  421 .  
      The connecting piece  43  is a T shape block. Each of two sides of a bottom thereof is extended with a horizontal beam  431 . A spring  44  is connected between one horizontal extending rod  421  and one retaining part  42 . Another spring  45  is connecting between the other horizontal extending rod  421  and the other retaining part  42 . Thereby, the connecting piece  43  is exactly received on the two symmetrical retaining parts  42 . Referring to  FIG. 8 , it is preferable that the angle θ between the horizontal beam  431  and the connecting piece is between 5°˜30°. In this range, the springs  44 ,  45  will have preferred elasticity and flexibility between the retaining parts  42  and the horizontal beams  431 .  
      The switch piece  60  is connected to the connecting piece  43  by inserting a screw  80  into a front screw hole  61 . The arched column  64  on a bottom surface of the switch piece  60  is slightly small than the width of the arched hole  32  on the cover plate  30 , as shown in  FIG. 1B . Further, the arched column  64  is engaged with an arched groove  432  on the top surface of the connecting piece  43 . Thereby, an angular shift when the screw  80  is tightened can be avoided, and the switch piece  60  will be capable of being slid in the left and right directions in the top portion of the wrench handle  10 . The bottom surface of the switch piece  60  are provided with a first retaining hole  62  and a second retaining hole  63  for retaining a second pushing unit housed within a retaining hole  16  of the wrench handle  10  and consisting of a spring A 1  and a steel ball B 1 , whereby the switching of the switch piece  60  will be properly positioned.  
      Further, the ratchet tool of the present invention can be provided with a decorative plate  70  over the cover plate  30 , the braking piece  40  and the switch  60 . The decorative plate  70 , similar in geometry to the cover plate  30 , has a through hole  71  connected with an arched projected portion, wherein an arched hole  72  corresponding to the arched hole  32  is formed. The decorative plate  70  is for an ornamental and anti-dust purpose.  
      Referring to  FIGS. 2 and 3 , the assembly of a ratchet tool of the present invention is superior to the conventional ratchet tool. To assemble a ratchet tool of the present invention, the braking piece  40  and the connecting piece  43  are combined through the first and second resilient parts  44 ,  45 . Secondly, the spring A and the steel ball B of the first pushing unit are placed into the through hole  14 ; then the combined component of the braking piece  40  and the connecting piece  43  is placed in the second receptacle area  13 , the steel ball B being pushed simultaneously. The ratchet wheel  20  is then placed in the first receptacle area  12 , and the cover plate  30  is coupled with the annular groove  122  of the first receptacle area  12 . At this time, the two symmetrical blocking pieces  42  on the top surface of the braking piece  40  and the connecting piece  43  are disposed in the arched hole  32 . The first and second receptacle areas  12 ,  13  are enclosed, preventing the departure of a ratchet wheel  20  and the braking piece  40  from the box head  11  of the wrench handle  10 . Eventually, the decorative plate  70  is attached onto the cover plate  30  and fixed thereon by the screw  80  that goes through the front screw hole  61  on the of the switch piece  60 , the arched hole  72  on the decorative plate  70 , the arched hole  32  on the cover plate.  30  and the hole with a screw thread extended in an axial direction within the connecting piece  43 . Further, the arched projected column  64  will be engaged within the top arched groove  432 , whereby an angular shift of the screw  80  as it is tightened can be avoided. Thereby, the smooth slide of the column  64  along the arched hole  32  can be guaranteed.  
      Referring to  FIGS. 5, 6  and  7 , the primary objective of the present invention is to produce louder noises when the ratchet wrench is undergoing a backward reposition for better recognition by the user.  
      Referring to  FIG. 5 , when the switch piece  60  is switched in the clockwise direction, the braking piece in the second receptacle area  13  will be tilted against the left wall of the receptacle area  13 . As shown in  FIG. 6 , the connecting piece  43  pivotally connected with the switch piece  60  will move to the left slightly. Since the blocking pieces  42  on the top surface of the braking piece  40  are provided with a first and a second resilient parts  44 ,  45 , the first resilient part  44  will move to the left wall of the second receptacle area  13  and contract, whereas the second resilient part  45  will stretch, whereby by the braking piece  40  will be pushed by first pushing unit in the through hole  14  in the rear portion of the second receptacle area  13 . Thereby, the teeth portion  41  of the braking piece  40  will be engaged with the outer ratchet teeth  22  around the ratchet wheel  20 . Being pushed from three directions, the let side of the braking piece  40  tilts against the left inner wall of the second receptacle area  13 , whereby the ratchet wheel  20  will be driven in the counterclockwise direction.  
      Referring to  FIG. 6 , when the wrench handle  10  is twist in a counterclockwise direction to drive a bolt or a nut over a certain angle and encounters obstacle, a backward (in a clockwise direction) reposition is necessary, as shown in  FIG. 7 . Since the force for this clockwise reposition is larger than the pushing force exerted by the first pushing device, the first and the second resilient pieces, the braking piece  40  coupled with the ratchet wheel  20  will move toward the right side of the second receptacle area  13  and the second receptacle area  13  will contract accordingly, whereby the teeth portion  41  of the braking piece  40  will move over the ratchet teeth  22  of the ratchet wheel  20 , and then the restoring force of the first pushing device, the first and the second resilient pieces will draw the braking piece  40  back to its original configuration. Such a process can go continuously to achieve an effect of backward reposition of the wrench handle  10 .  
      In addition to the force of the first pushing device, the braking piece  40  of the present invention is exerted by the restoring forces of the first and the second resilient pieces disposed between the retaining parts  42  and the connecting piece  43  formed on the top surface of the braking piece  40 . Thereby, as the ratchet wheel  20  is rotating backward, the three forces mentioned above will produce loud enough noises to remind a user of the action of backward reposition.  
      To sum up, a ratchet tool of the present invention has the advantages of:  
      1. structural simplicity for easy assembly; and  
      2. producing louder noises for reminding backward reposition.  
      The present invention is thus described, and it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.