Patent Publication Number: US-7210234-B2

Title: Bow saw structure

Description:
BACKGROUND OF THE INVENTION 
   The present invention is related to a bow saw structure including an adjustment unit for controlling the depth of a tunnel of the handle. By means of adjusting the depth of the tunnel, different lengths of saw blades can be replaced with each other. A fast installation/detachment unit and the handle are arranged on the same side of the bow saw. By means of the fast installation/detachment unit, a user can quickly and conveniently replace the saw blade. 
     FIG. 8  shows a conventional bow saw  7  integrally having a handle  8  for a user to hold. A butterfly nut  81  is disposed on one side of the bow saw  7  opposite to the handle  8 . When mounting a saw blade  82  on the bow saw  7 , the butterfly nut  81  can be tightened to fix the saw blade  82  with the handle  8 . When detaching the saw blade  82 , the butterfly nut  81  must be unscrewed for taking off the saw blade  82 . 
   It is necessary to screw or unscrew the butterfly nut  81  for installing or detaching the saw blade  82 . Therefore, it is time-consuming to replace the saw blade  82 . 
   Moreover, when installing the saw blade  82 , a user needs to hold the saw blade  82  with one hand and screw the butterfly nut  81  with the other hand. This is quite inconvenient to the user. 
   Also, the bow saw  7  is integrally formed so that only the saw blade with the same length can be mounted on the bow saw  7 . A longer or shorter saw blade is not applicable to the bow saw  7 . 
   SUMMARY OF THE INVENTION 
   It is therefore a primary object of the present invention to provide an improved bow saw structure including a fast installation/detachment unit pivotally disposed on lower side of the handle. By means of the fast installation/detachment unit, a user can quickly and conveniently fix or loosen the saw blade. The bow saw further includes an adjustment unit by which different lengths of saw blades are installable on the bow saw. 
   According to the above object, the bow saw structure of the present invention includes a handle, an adjustment unit and a fast installation/detachment unit. 
   The handle has a grip section for a user&#39;s hand to extend through and hold. An upper side of the grip section is formed with a tunnel in which a first tightening member is disposed. 
   The adjustment unit is mounted on the upper side of the grip section for controlling the depth of the tunnel. Two sides of the adjustment unit are respectively formed with two projecting sections. 
   The fast installation/detachment unit is pivotally disposed on lower side of the handle. A tightening member is arranged in the fast installation/detachment unit. One end of the tightening member protrudes from the handle. 
   The present invention can be best understood through the following description and accompanying drawings wherein: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective assembled view of a first embodiment of the present invention; 
       FIG. 2  is a perspective exploded view of the first embodiment of the present invention; 
       FIG. 3  is a side view of the first embodiment of the entire bow saw of the present invention; 
       FIG. 4  is a side view of the first embodiment of the present invention, showing that the support member is adjusted by means of the adjustment unit; 
       FIG. 5  is a sectional view of the first embodiment of the present invention, showing that the adjustment unit is mounted in a window of the handle; 
       FIG. 6  is a sectional view of the first embodiment of the present invention, showing that the fast installation/detachment unit is pivotally connected with the handle; 
       FIG. 7  is a side view of a second embodiment of the bow saw of the present invention; and 
       FIG. 8  is a side view of a conventional bow saw. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Please refer to  FIGS. 1 to 7 . The bow saw structure of the present invention includes a handle  1 , an adjustment unit  2  and a fast installation/detachment unit  3 . 
   The handle  1  has a grip section  11  for a user&#39;s hand to extend through and hold. An upper side of the grip section  11  is formed with a tunnel  12  for one end of an L-shaped support member  4  to insert therein. The other end of the L-shaped support member  4  is formed with a split  41  in which a saw blade  5  can be located 
   The adjustment unit  2  is mounted on upper side of the grip section  11  for controlling the depth of the tunnel  12 . The adjustment unit  2  has a triangular protrusion  22  extending from a top thereof and the triangular protrusion  22  has an end  222  contacting against the L-shaped support member  4 . When the adjustment unit  2  moves upward into the tunnel  12 , the triangular protrusion  22  contacts the L-shape member, so that the depth of the tunnel  12  is shallow. When the adjustment unit  2  moves downward to retract from the tunnel  12 , the depth of the tunnel  12  is deep. By means of adjusting the depth of the tunnel  12 , the L-shaped support member  4  can be inserted into the tunnel  12  by different depth. Accordingly, the length of the L-shaped support member  4  can be adjusted. Accordingly, different length of saw blades  5  can be replaced with each other. 
   The upper side of the handle  1  is formed with a window  13  in which the adjustment unit  2  is placed. 
   Two sides of the adjustment unit  2  are respectively formed with sections  21 . The projecting section  21  has one slope  211 . The window  13  includes two L-shaped recesses  131  therein and when the adjustment unit  2  is located in the window  13 . The projecting section  21  retracts inward and the slopes  211  are engaged with the recesses  131 . By means of the slopes  211 , the adjustment unit  2  can be obliquely installed into the window  13  of the handle  1 . In addition, the projecting section  21  prevents the adjustment unit  2  from dropping out of the window  13 . 
   The fast installation/detachment unit  3  is pivotally disposed on lower side of the handle  1 . A second tightening member  31  is arranged in the fast installation/detachment unit  3 . In this embodiment, the second tightening member  31  is composed of a connection piece  32  having a threaded end  322  and a knob  31  having a threaded inner periphery  311 . The connection piece  32  and the knob  31  are tightly connected to each other. One end of the connection piece  32  protrudes from the handle  1  and is formed with a notch  323  in which the saw blade  5  is located. 
   The lower side of the handle  1  is formed with two depressions  14  each having an opening  15 . The fast installation/detachment unit  3  has two bosses  33  which can be located in the depressions  14  to pivotally connect the handle  1  with the fast installation/detachment unit  3 . 
   When installing the saw blade  5 , the saw blade  5  is first placed into the split  41  of the support member  4  and the notch  323  of the connection piece  32 . Then the knob  311  is tightened to fix the saw blade  5 . The second tightening member  31  and the handle  1  are on the same side of the bow saw. Therefore, when installed, a user needn&#39;t hold the saw blade  5  with one hand. This facilitates the installation of the saw blade  5 . 
     FIG. 7  shows a second embodiment of the present invention, which is substantially identical to the first embodiment. The second embodiment is different from the first embodiment in that the support member  4  of the first embodiment is replaceable with a saw blade  6 . The first tightening member  62  has a threaded inner periphery  63 . The saw blade  6  has a threaded projection  64 , after the saw blade  6  is inserted into the tunnel  61 . The threaded inner periphery  63  is connected to the threaded projection  64 , and tightening member  62  securelyconnects the threaded projection  64  to the tunnel  61 . The saw blade  6  can be easily and quickly replaced. The present invention can be another type of saw simply by replacing the L-shaped support member  4  with the saw blade  6 . 
   The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.