Abstract:
An improved adjusting structure for a ratchet wrench having a tool handle. One end of the tool handle is provided with an open chamber sealed by a seal piece. The chamber is provided with a trigger structure including: a ratchet wheel disposed at an end portion of the chamber; a positioning groove provided in a wall of another end portion of the chamber; a trigger block having one end portion disposed in the positioning groove, the other end portion and the ratchet wheel being provided with two confronting toothed faces, the trigger block being swingable left and right in the positioning groove; and a trigger structure disposed outside the chamber and being operable to control the trigger block such that one of the toothed faces engages the ratchet wheel.

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a wrench tool, more particularly to an improved adjusting structure for a ratchet wrench. 
     (b) Description of the Prior Art 
     Referring to FIGS. 1 and 2, a conventional ratchet wrench essentially includes a chamber with an open bottom provided at a working end at a head portion of the wrench. One end of the chamber is provided with a ratchet wheel. The center of the ratchet wheel is connected to a drive rod. The center of the drive rod is provided with a movable type insert control member that controls the drive rod to stably couple with a workpiece or another fitting member. The insert control member is controlled via a push button extending out of the drive rod and a top face of the chamber. The other end of the chamber is provided with two curved grooves in a wall surface thereof for limiting base portions of two trigger blocks. Open ends of the two trigger blocks have teeth that are engageable with peripheral teeth of the ratchet wheel. An eccentric push rod is disposed between the two trigger blocks. The push rod is controlled via a trigger rod provided at a top face of the wrench. Two side walls of the chamber are respectively provided with springs urging against the trigger blocks. 
     The trigger rod is manipulated to cause the push rod to push away one of the trigger blocks so that the push block compresses the corresponding spring, and the teeth of the trigger block disengage from the ratchet wheel. On the contrary, the other trigger block or the urging action of the other spring causes the teeth to engage with the ratchet wheel. Thus, operation of the wrench can produce a predetermined operating direction, or conversely, the wrench is in idle rotation to return to its original position. 
     The above-described conventional ratchet wrench has the following disadvantages: 
     1. The torque of the wrench is small. The number of teeth that can be provided at the end portion of the elongated trigger block is limited. Insufficient number of engageable teeth between the ratchet wheel and the trigger block results in small torque of the wrench, which may cause wear or damage of the teeth during operation. Besides, engagement is not assured, which may affect operation of the wrench. 
     2. A large number of components make assembly inconvenient and time-consuming. During assembly, the two trigger blocks have to be disposed first. Then, the eccentric push rod is assembled, and it has to be noted that rotation of the push rod can push away one of the trigger blocks. Next, the push rod and the push rod are coupled. Subsequently, two springs are fitted between the two trigger blocks and the two side walls. Assembly is very completed and time-consuming. 
     3. Positioning of the components is not secure. The springs are simply mounted by fitting without any positioning means and may easily become disengaged. The base portions of the two trigger blocks are only limited in the two curved grooves and may disengage in the direction of the ratchet teeth. These problems seriously affect the operation and durability of the wrench. 
     SUMMARY OF THE INVENTION 
     The main object of the present invention is to provide an improved adjusting structure for a ratchet wrench, in which the wrench can bring a workpiece to rotate in an action direction or to perform idle rotation in a reverse direction back to its original position. In addition, the present invention can be quickly assembled and positioned, and the torque of the wrench can be increased. Furthermore, the wrench can drive the workpiece with a stable and uniform force, thereby enhancing operability and durability of the wrench. 
     In order to achieve the aforementioned object, the improved adjusting structure according to the present invention is adapted for use in a tool handle. One end of the tool handle is provided with an open chamber sealed by a seal piece. The chamber is provided with a trigger structure including: a ratchet wheel disposed at an end portion of the chamber; a positioning groove provided in a wall of another end portion of the chamber; a trigger block having a circular block-shaped base portion and a toothed block expanding radially outward from the base portion, the base portion being disposed in the positioning groove, the base portion of the trigger block being centrally provided with a polygonal hole; a trigger structure including a disk portion, one side of the disk portion being provided with a shaft that is provided with a polygonal block, the shaft extending into the trigger block, the polygonal block fitting into the polygonal hole; a positioning assisting structure including at least one through hole formed in the toothed block of the trigger block, the through hole having a spring fitted therein. The spring has two ends, each of which is provided with a positioning ball. The positioning ball has an end portion provided with a positioning rod extending through and being retained in the spring. The wall surface of the chamber and the seal piece are respectively provided with hemispherical recesses at positions corresponding to positions adjacent to the positioning balls such that when the trigger block is actuated by the trigger structure to slant and the toothed face on one side engages the ratchet wheel, the peripheral surfaces of the two positioning balls can engage the hemispherical recesses on the same side. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features and advantages of the present invention will be more clearly understood from the following detailed description and the accompanying drawing, in which, 
     FIG. 1 is a perspective view of a conventional wrench; 
     FIG. 2 is a plan view showing the internal construction of the conventional wrench; 
     FIG. 3 is an exploded perspective view of the present invention; 
     FIG. 4 is a plain view of a tool handle of the present invention; 
     FIG. 5 is an assembled perspective view of the present invention; 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG. 5; 
     FIG. 7 is a schematic plan view illustrating operation of the present invention; 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG. 5; 
     FIG. 9 is another schematic plan view illustrating operation of the present invention; and 
     FIG. 10 is a sectional view taken along line  10 — 10  of FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 3 to  6 , the preferred embodiment of an improved adjusting structure for a ratchet wrench according to the present invention mainly includes a tool handle  20 , a ratchet  30 , an trigger block  40 , an actuating structure  50 , a seal piece  60 , and a positioning assisting structure. 
     The tool handle  20  has a working end  21  at one end and a grip end  22  at the other end. The working end  21  has a chamber  23  with a downward open end disposed therein. A ratchet wheel opening  231 , two screw holes  232 , a shaft hole  233  are respectively to extend through a top wall of the chamber  23 . The side wall of the chamber  23  that is proximate to the shaft hole  233  is provided with a curved positioning groove  24  having an opening that is in a contracted form. 
     The ratchet wheel  30  is disposed in the end portion of the chamber  23  with the ratchet wheel opening  231 . The center of the ratchet wheel  30  is connected to a drive rod  31 . The drive rod  31  is provided with a movable type insert control member  311  for stable coupling with a workpiece or another connecting member. The insert control member  311  is controlled via a push button  32  that extends out of the drive rod  30  and the ratchet wheel opening  231 . 
     The trigger block  40  includes a curved block-like base portion  41  and a radially extending toothed block  42 . Both sides of the trigger block  40  are respectively provided with recessed limiting grooves  43 . The base portion  41  is disposed in the positioning groove  24  of the tool handle  20 . The limiting grooves  43  on the two sides are disposed to receive the contracted side wall end of the positioning groove  24  so that the trigger block  40  is positioned in the positioning groove  24  and will not slip in the direction of the ratchet wheel  30 . The toothed block  42  is a curved end face relative to the ratchet wheel  30  and has two ends respectively provided with toothed faces  421  formed by a plurality of ratchet teeth and respectively engageable with the ratchet wheel  30 . The base portion  41  of the trigger block  40  is centrally provided with a polygonal hole  45 . 
     The actuating structure  50  includes a disk portion  51 , a shaft  52  disposed on one side of the disk portion  51 , a polygonal block  53  provided on the shaft  52 . The other side of the disk portion  51  extends radially to form a trigger rod  54 . The disk portion  51  is provided outside the wall surface of the working end  21 . The shaft  52  passes through the shaft hole  233  into the trigger block  40 . The polygonal block  53  extends into the polygonal hole  45 . The shaft  52  extends out of the trigger block  40  and has a bottom end retained by a C-clip  55  to prevent the adjusting structure  50  from upward disengagement. By manipulating the trigger rod  54 , the trigger block  40  can be controlled to swing so that one of the toothed faces  421  engages with the ratchet wheel  30 . 
     The seal piece  60  is disposed in the opening of the chamber  23 , and is locked in position by passing two screw elements  61  through the screw holes  232 . 
     In the positioning assisting structure, the toothed block  42  of the trigger block  40  is provided with two through holes  422  each of which has an elastic positioning element disposed therein. The elastic positioning element includes a spring  423 . Two ends of the spring  423  are respectively provided with positioning balls  424 . A positioning rod  425  disposed at an end portion of the positioning ball  424  passes through the spring  423  and is positioned therein. The wall surface of the chamber  23  and the side of the seal piece  60  corresponding to positions proximate to the two elastic positioning elements are respectively provided with hemispherical recesses  25 ,  62  for retaining circular end heads of the positioning balls  424 . 
     Referring to FIGS. 7 to  10 , during operation of the movable wrench of the present invention, the trigger rod  54  is turned in a predetermined direction of action. The trigger rod  54  drives the disk portion  51  and the polygonal block  54 . Since the polygonal block  53  fits in the polygonal groove  35  in the trigger block  40 , the trigger block  40  can be brought to turn in the direction of the trigger rod  54  about an angle so that the toothed face  421  in that direction engages the toothed face of the ratchet wheel  30 . At this time, when the movable wrench holds a workpiece with the drive rod  31  and drives in the direction of action, the toothed face  421  of the trigger block  40  retains the ratchet wheel  30  so that the wrench brings the ratchet wheel  30  and the workpiece to turn in the action direction to tighten or loosen the workpiece. On the contrary, when the movable wrench is worked in the other direction, the toothed face  421  of the trigger block  40  will be pushed away by the ratchet wheel  30  in a reverse direction so that the ratchet teeth do not engage and the movable wrench rotates idly to the original position without actuating the ratchet wheel  30 . Since the positions of the two hemispherical recesses  25 ,  62  substantially correspond to the two elastic positioning elements, when the trigger block  40  is controlled by the trigger structure  50  to slant in a predetermined direction, with one of the toothed faces  421  engaging the ratchet wheel  30 , the positioning balls  424  of one of the elastic positioning elements will follow the slanting direction of the trigger block  40  to move toward and are retained in the hemispherical recesses  25 ,  62  nearby, while the positioning balls  424  of the other elastic positioning elements will move out of the hemispherical recesses  25 ,  62 , thereby achieving the function of assisting positioning of the trigger block  40 . The configuration of the elastic positioning elements in which either end of the spring  423  abuts against a positioning ball  424  can eliminate the clearance between the trigger block  40 , and the top wall of the chamber  23  and the seal piece  60  so that the arrangement is more secure. When one of the toothed faces  421  engages with the ratchet wheel  30 , the positioning balls  4245  on the same side will be retained in the hemispherical recesses  25 ,  62  to stabilize engagement. 
     The present invention has the following advantages: 
     1. The present invention employs a ratchet wheel  30 , a trigger block  40  and a trigger structure  50  to enable the movable wrench to drive a workpiece or to rotate idly so as to return to its original position. 
     2. The trigger block  40  is preformed as a block with the base portion thereof  41  disposed in the positioning groove  24  so as to be positioned therein. The configuration of the limiting groove  43  and the contracted end wall of the positioning groove  24  further enhances the positioning of the trigger block  40  so that it will not slip. This not only provides the advantage of quick assembly, positioning can also be done with the assembly operation in one time. 
     3. In the present invention, the trigger block  30  includes a toothed block  42  with two toothed faces  421  engageable with the ratchet wheel  30 . Since the area of the toothed block  42  is large, the number of teeth on the toothed face  421  can also be increased to enlarge the area of engagement, which can increase the driving force of the trigger block  40 , thereby increasing the torque of the wrench to drive the workpiece with a larger force without the toothed face of the trigger block  40  being broken. 
     4. The present invention has a positioning assisting structure. When the trigger block  40  is turned slantingly, and the toothed face  421  on one side thereof engages the ratchet wheel  30 , the positioning balls  424  on the same side will displace to the nearby hemispherical recesses  25 ,  62  to stabilize engagement, so that the trigger block  40  can drive the ratchet wheel  30  to rotate in the action direction with a more stable balancing force. 
     5. All of the above advantageous features of the present invention enhance the operability and durability of the wrench. 
     Although the present invention has been illustrated and described with reference to the preferred embodiment thereof, it should be understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.