Patent Publication Number: US-9889544-B2

Title: Ratchet wrench

Description:
BACKGROUND OF THE INVENTION 
     1. Fields of the Invention 
     The present invention relates to a ratchet wrench, and more particularly, to a ratchet wrench for easily adjusting the clamping size to fasten or loosen objects of different sizes. 
     2. Descriptions of Related Art 
     The conventional way to fasten or loosen an object such as a bolt, is to use a ratchet wrench which allows the user to continuously rotate the object without dismounting and re-mounting the wrench from the object frequently. The conventional ratchet wrench is usually cooperated with a socket which is mounted to the bolt head and the ratchet wrench is rotated to drive the socket to fasten or loosen the bolt. However, the socket has a fixed size so that when the bolts have different sizes, the user has to replace the sockets of different sizes. The multiple sockets are heavy and occupy space. 
     The present invention intends to provide a ratchet wrench which has the feature to adjust the clamping size such that the objects of different sizes can be fastened or loosened by using the same ratchet wrench without being cooperated with multiple sockets. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a ratchet wrench and comprises a head and a handle, wherein the head has a through hole and a reception hole is defined in the inner periphery of the through hole. A positioning unit is located in the reception hole to bias a pawl in the head. The pawl has a projection extending from the rear side thereof, and multiple engaging teeth are formed on the front side thereof. The pawl is located in the head and connected with a switch. A collar is located in the through hole of the head and has a hole defined centrally therethrough. The diameter of the hole of the collar is smaller than that of the collar so as to form a ring-shaped portion enclosing the hole. A peripheral wall extends from the first side of the collar and two notches are defined in the peripheral wall. A curved groove is defined through the ring-shaped portion of the collar. Two toothed racks are formed along the groove. An engaging unit has a pin and a lever, wherein the pin has a hole  511  defined transversely therethrough. The pin extends through the groove from the first side of the collar, and the lever  52  is located on the second side of the collar and is pivotably connected to the pin. The pin has a hook. 
     A ratchet wheel is located in the collar and has ratchet teeth formed on the outer periphery thereof. The ratchet wheel has a room defined therein and two protrusions extend inward from the inner periphery of the room. A recess is defined in the first side of the ratchet wheel and the pin is inserted in the recess. Two curved guide slots are respectively defined in the first side of the ratchet wheel and the second side of the ratchet wheel. Two clamp members are located in the room of the ratchet wheel and each have two lugs extending from the outside thereof. The two lugs of each clamp member each have a guide rod extending from the facing side thereof. The guide rods of the two clamp members are located in the guide slots. A cover having an opening is connected to the head to restrict the ratchet wheel within the head. 
     Preferably, the positioning unit has a spring and a bead which is biased by the spring. 
     Preferably the collar has a flange extending outward from the peripheral wall extending from the first side of the collar. The collar is connected to the head. 
     Preferably, the collar has ridges extending from the outer periphery thereof. 
     Preferably, the two clamp members each are a V-shaped plate. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view to show the ratchet wrench of the present invention; 
         FIG. 2  is an exploded view of the ratchet wrench of the present invention; 
         FIG. 3  is an exploded view of the collar and the engaging unit of the ratchet wrench of the present invention; 
         FIG. 4  is a top view of the ratchet wrench of the present invention; 
         FIG. 5  is a cross sectional view, taken along line  4 - 4  of  FIG. 4 ; 
         FIG. 6  is a cross sectional view of the ratchet wrench of the present invention; 
         FIG. 7  shows that the engaging unit of the ratchet wrench of the unit of present invention is operated; 
         FIG. 8  shows that the clamp members are moved toward each other, and 
         FIG. 9  shows that the clamp members are moved away from each other. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 to 9 , the ratchet wrench  10  of the present invention comprises a head  11  on one end of a handle, and the head  11  has a through hole  111  defined therethrough. A recess is defined in an inner periphery of the through hole  111  so as to receive a pawl  30  therein. A reception hole  112  is defined in the inner periphery of the recess and a positioning unit  20  is located in the reception hole  112 . The positioning unit  20  has a spring  21  and a bead  22  which is biased by the spring  21 . 
     The pawl  30  has a projection  31  extending from the rear side thereof, and multiple engaging teeth  32  are formed on the front side thereof and located at two ends of the front side. The pawl  30  is connected with a switch  33  to control the movement of the pawl  30 . 
     A collar  40  is located in the through hole  111  of the head  11  and has a hole defined centrally therethrough. The diameter of the hole of the collar  40  is smaller than the diameter of the collar  40  so as to form a ring-shaped portion enclosing the hole. A peripheral wall extends from the first side of the collar  40 , and two notches  41  are defined in the peripheral wall. A curved groove  42  is defined through the ring-shaped portion of the collar  40 . Two toothed racks  43  are formed along the groove  42  and extend from the first side of the collar  40 . The collar  40  has a flange  44  extending outward from the peripheral wall extending from the first side of the collar  40 . By the flange  44 , the collar  40  is connected to the head  11 . The collar  40  has ridges  45  extending from the outer periphery thereof so that the user can easily hold and rotate the collar  40 . 
     An engaging unit  50  has a pin  51  and a lever  52 , wherein the pin  51  has a hole  511  defined transversely through the first end thereof. The first end of the pin  51  extends through the groove  42  from the first side of the collar  40 . The lever  52  is located on the second side of the collar  40  and has a slot  521 . The first end of the pin  51  is pivotably connected to slot  521  by extending a pivot through the slot  521  and the hole  511  of the pin  51 . The pin  51  has a hook  512  formed on a lateral surface thereof and located close to the second end of the pin  51 . 
     A ratchet wheel  60  is located in the collar  40  and has ratchet teeth  61  formed on the outer periphery thereof. The ratchet wheel  60  has a room  62  defined therein and two protrusions  63  extend inward from the inner periphery of the room  62 . A recess  64  is defined in the first side of the ratchet wheel  60  and the pin  50  is inserted in the recess  64 . Two curved guide slots  65  are respectively defined in the first side of the ratchet wheel  60  and the second side of the ratchet wheel  60 . 
     Two clamp members  70  are located in the room  62  of the ratchet wheel  60  and each have two lugs  71  extending from an outside thereof. The two clamp members  70  each are a V-shaped plate. The two lugs  71  of each clamp member  70  each have a guide rod  711  extending from the facing side thereof. The guide rods  711  of the two clamp members  70  are located in the guide slots  65 . A cover  80  having an opening  81  is connected to the head  11  to restrict the ratchet wheel  60  in the head  10 . 
     When the user wants to clamp an object with a rectangular head or a hexagonal head (not shown), the head of the object is put between the two clamp members  70  and the user rotates the collar  40 . The two clamp members  70  move along the room  62  of the ratchet wheel  60  to a proper position as shown in  FIGS. 7 to 9  so as to clamp the object. The lever  52  is then pivoted downward to lift the pin  51  upward such that the hook  512  is engaged with the toothed racks  43  of the collar  40  as shown in  FIGS. 4 and 5 . Therefore, the two clamp members  70  will not move to release the object, and the collar  40  is secured and cannot be rotated. The engaging teeth  32  of the pawl  30  are engaged with the ratchet teeth  61  of the ratchet wheel  60 . The object can be rotated by rotating the handle to tighten or loosen the object. There will be not necessary to prepare the sockets of different sizes. 
     When the object is tightened or loosened, the lever  52  is pivoted upward to lower the pin  51 , and the hook  512  is disengaged from the toothed racks  43  of the collar  40 . The collar  40  is then rotatable and the two clamp members  70  are released from the object. The ratchet wrench  10  can be removed from the object. 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.