Abstract:
A tool bit adapter installed in a reciprocating pneumatic tool for locking a tool bit to an impact cylinder of the pneumatic tool is disclosed to include a socket fastened to the impact cylinder of the pneumatic tool, a stop member movably mounted on the socket, the stop member having a stop portion and an engagement space movable between a locking position to lock a tool bit to the impact cylinder and an unlocking position to let the user remove the tool bit from the impact cylinder, and a spring member coupled between the socket and the stop member to hold the stop member in the locking position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to pneumatic tools and more particularly, to a tool bit adapter for use in a reciprocating pneumatic tool to couple a tool bit to an impact cylinder of the pneumatic tool.  
         [0003]     2. Description of the Related Art  
         [0004]     When a tool bit is installed in a conventional reciprocating pneumatic tool, a helical spring is fastened to an impact cylinder to lock the tool bit. The helical spring has a hooked portion at the front side for stopping the installed tool bit in place. During installation, the user must rotate the helical spring through several turns so that the helical spring can hold the tool bit firmly in place. When unloading the tool bit, the user must rotate the helical spring in the reversed direction. This mounting and/or dismounting procedure is complicated, wasting much time. Further, the hooked portion of the helical spring tends to be deformed accidentally by an external object, resulting in falling of the tool bit from the pneumatic tool.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a tool bit adapter, which allows quick change of the tool bit, saving much tool bit mounting and/or dismounting time. It is another object of the present invention to provide a tool bit adapter, which has a simple structure that is easy to install and to operate.  
         [0006]     To achieve these and other objects of the present invention, the tool bit adapter is installed in a reciprocating pneumatic tool and adapted to lock a tool bit to an impact cylinder of the pneumatic tool, comprising: a socket, the socket having a socket body and mounting means for fastening the socket body to the impact cylinder of the pneumatic tool; a stop member movably mounted on the socket, the stop member having a stop portion and an engagement space movable between a locking position for locking the tool bit to the impact cylinder and an unlocking position for enabling the installed tool bit to be removed from the impact cylinder; and a spring member coupled between the socket and the stop member to hold the stop member in the locking position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a schematic drawing showing a tool bit adapter installed in a reciprocating pneumatic tool according to the present invention.  
         [0008]      FIG. 2  is a sectional assembly view of the tool bit adapter according to the present invention.  
         [0009]      FIG. 3  is an exploded plain view of the tool bit adapter according to the present invention.  
         [0010]      FIG. 4  is a side view of the stop member shown in FIG,  3 .  
         [0011]      FIG. 5  corresponds to  FIG. 1  showing the stop member unlocked from the tool bit.  
         [0012]      FIG. 6  shows the socket formed integral with the impact cylinder according to the present invention.  
         [0013]      FIG. 7  shows the structure of the coiled portion of the stop member according to the present invention.  
         [0014]      FIG. 8  is a front assembly view of an alternate form of the tool bit adapter according to the present invention.  
         [0015]      FIG. 9  is a side assembly view of another alternate form of the tool bit adapter according to the present invention.  
         [0016]      FIG. 10  is a front assembly view of still another alternate form of the tool bit adapter according to the present invention.  
         [0017]      FIG. 11  is a front assembly view of still another alternate form of the tool bit adapter according to the present invention.  
         [0018]      FIG. 12  illustrates the structure of the stop member shown in  FIG. 11 .  
         [0019]      FIG. 13  is a schematic drawing showing still another alternate form of the tool bit adapter according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Referring to  FIG. 1 , a tool bit adapter is connectable to an impact cylinder  70  of a reciprocating pneumatic tool for holding a tool bit  80 .  
         [0021]     The impact cylinder  70  has a threaded neck  75  and an axial insertion hole  77  axially extending through the threaded neck  75 . The tool bit  80  has a shank  81  and a stop flange  83  around the periphery of the shank  81 .  
         [0022]     Referring to FIGS.  2 ˜ 4  and  FIG. 1  again, the aforesaid tool bit adapter comprises a socket  10 , a stop member  20 , a control cap  30 , and a spring member  40 .  
         [0023]     The socket  10  has a hollow socket body  11 , a mounting portion  13 , for example, an inner thread provided inside the socket body  11  for threaded onto the threaded neck  75  of the impact cylinder  70 , a stop flange  14  extending around the periphery of one end, namely, the rear end of the socket body  11 , two pivot holes  15  symmetrically provided at two sides of the socket body  11  near the other end, namely, the front end of the socket body  11 , a bumper  17  extending from the front side of the socket body  11 , and an axle hole  18  axially extending through the front side of the socket body  11  for protecting the stop member  20  from being bumped.  
         [0024]     The stop member  20  according to this embodiment is formed of a curved wire rod, having two bearing portions  21 , two pivot tips  23  respectively pivoted to the pivot holes  15  of the socket  10 , two spring arms  24  respectively connected between the bearing portions  21  and the pivot tips  23 , a stop portion  25  of arch frame connected between the bearing portions  21  remote from the spring arms  24 , an engagement space  26  surrounded by the stop portion  25 , and a receiving space  27  surrounded by the spring arms  24  and the bearing portions  21  in communication with the engagement space  26  at the lower side.  
         [0025]     The control cap  30  has a cap body  31  capped on the socket body  11  of the socket  10 , a through hole  33  formed in the cap body  31  for the passing of the socket body  11  of the socket  10 , and a cap flange  35  extending around the periphery of the cap body  31  and surrounding a part of the spring member  40 .  
         [0026]     The spring member  40  according to this embodiment is a compression spring, having a spring body  41  sleeved onto the socket body  11  of the socket  10 , a first end  43  stopped against the stop flange  14  of the socket  10 , and a second end  44  stopped against the cap body  31  of the control cap  30 .  
         [0027]     Referring to  FIG. 5  and  FIG. 1  again, when pulling the control cap  30  backwards, the stop member  20  is biased in one direction. At this time, the engagement space  26  of the stop member  20  is deviated from the centerline of the impact cylinder  70 , allowing insertion of the tool bit  80  into the impact cylinder  70  through the receiving space  27  of the stop member  20  and forming an unlocking position. After insertion of the shank  81  of the tool bit  80  into the axial insertion hole  77  of the impact cylinder  70 , the control cap  30  is released from the hand, enabling the control cap  30  to be pushed forwards to its former position by the spring member  40  to further return the stop member  20  to its former position, thereby causing the stop portion  25  and engagement space  26  of the stop member  20  to be held in positive engagement with the stop flange  83  of the tool bit  80  and forming an locking position, therefore the tool bit  80  is locked to the impact cylinder  70 .  
         [0028]      FIG. 6  shows an alternate form of the present invention. According to this embodiment, the socket  10 A is a part of the impact cylinder, i.e., the socket  10 A can be formed integral with the impact cylinder or fixedly fastened to the impact cylinder.  
         [0029]      FIG. 7  shows another alternate form of the present invention. According to this embodiment, the stop member  20 A has a coiled portion  22 A that enhances the springy power of the stop member  20 A.  
         [0030]      FIGS. 8 and 9  show still another alternate form of the present invention. The tool bit adapter according to this embodiment is comprised of a socket  10 B, a stop member  20 B, and a spring member  40 B. The spring member  40 B is a torsional spring formed integral with the stop member  20 B. The stop member  20 B has two pivot holes  23 B pivotally connected to the socket  10 B with a pivot bolt  61 . The spring member  40 B has a second stop portion  44 B stopped at a part of the socket  10 B. Alternatively, the stop member  20 B and the spring member  40 B can be two independent members fastened together.  
         [0031]     Further, the stop member in either of the aforesaid various alternate forms of the present invention can be made having a handle for operating by the user&#39;s hand, i.e., for pulling or pushing by the user to move the stop member to the locking or unlocking position.  
         [0032]      FIG. 10  shows still another alternate form of the present invention.  
         [0033]     According to this embodiment, the stop member  20 C is slidably mounted on the socket  10 C, and the spring member  40 C is supported between the stop member  20 C and the socket  10 C. According to this embodiment, the user can press the stop member  20 C vertically downwards from the locking position to the unlocking position for allowing installation of the tool bit. When released the hand from the stop member  20 C after insertion of the tool bit into the impact cylinder, the spring member  40 C pushes the stop member  20 C upwards from the unlocking position to the locking position.  
         [0034]      FIGS. 11 and 12  show still another alternate form of the present invention. According to this embodiment, the stop member  20 D is formed of a plate member, having an engagement space  26 D and a receiving space  27 D in communication with the engagement space  26 D at the upper side; the socket  10 D has a coupling groove  19 D for receiving the engagement space  26 D of the stop member  20 D to hold the stop member  20 D in the locking position.  
         [0035]     The stop member of aforesaid two embodiments still can be operated by pulling action instead and moved to the unlocking position.  
         [0036]      FIG. 13  shows still another alternate form of the present invention. According to this embodiment, the socket  10 E has two upwardly forwardly extending sliding grooves  19 E at two sides; the stop member  20 E has two coupling portions  29 E respectively coupled to the sliding grooves  19 E of the socket  10 E.  
         [0037]     As indicated above, the invention provides a tool bit adapter for reciprocating pneumatic tool, which has the following advantages: 
        1. The tool bit adapter allows quick change of the tool bit, saving much tool bit mounting and/or dismounting time.     2. The tool bit adapter has a simple structure that is easy to install and to operate.