Abstract:
A power tool including a housing, a motor, a transmission, a handle, an adjustable torque clutch, wherein at least a portion of the torque clutch is illuminated. Illumination of the torque clutch permits the user to identify the work mode or torque value of the torque clutch clearly in all working conditions, including dimly lit conditions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. 119 to CN 200820161628.X filed Oct. 9, 2008, and is hereby incorporated by reference. 
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       TECHNICAL FIELD 
       [0003]    The present invention relates to a power tool, and more particularly, to an illuminate torque clutch for a power tool. 
       BACKGROUND OF THE INVENTION 
       [0004]    Generally, the torque of a standard power tool can be adjusted through a rotatable torque clutch. A numerical scale is typically provided on the torque clutch to indicate the level of torque. For example, a typical power tool as shown in  FIG. 1  may have several different work modes and torque options. This power tool has a torque clutch having a scale  24 , wherein the scale  24  is composed of a set of numbers  23  and an indicator  25 . The housing of the scale  24  is transparent so the numbers can be seen while the torque clutch is rotated to the desired position. Alternatively, the numbers may be brightly colored. 
         [0005]    When the operating environment is dark, the user may have difficulty identifying the numbers of the scale  24 , and may choose an undesired work mode or torque. Misoperation and damage of the workpiece may result if the wrong level of torque is being used on an inappropriate piece of material. 
         [0006]    Typically, a power tool includes a work light. The work light is typically placed on the housing of the power tool and under the torque chuck, which is facing the workpiece. An ON/OFF trigger may be used to turn the work light on and off. The work light illuminates the workpiece in front of the power tool when the operating environment is dark. 
         [0007]    However, the work light can only illuminate a small area in front of the power tool, because the work light faces the workpiece and usually uses an LED which may not be bright enough. Therefore, it is not easy for the user to choose the desired work mode or adjust the torque of the power tool in a dimly lit environment, because the work light, in view of its placement, is not able to illuminate on the torque clutch. Thus, the user may chose the incorrect work mode and/or the torque setting, resulting in misoperation and possible damage to the workpiece. 
         [0008]    The present invention overcomes the disadvantages of the prior art by providing a power tool having an illumination means. The illumination means permits the user to read and set the proper torque and work setting of the power tool even in dimly lit situations. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a power tool which can be used in any lighting conditions, including dimly lit environments. The power tool includes a housing, a motor, a transmission arrangement, a handle, and an adjustable torque clutch, wherein the torque clutch is illuminated by a light source. Preferably, the light source is located inside the power tool, and the torque clutch is constructed of a transparent material. Alternatively, the torque clutch is illuminated by a fluorescent or light absorbing and reflective material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompany drawings, wherein: 
           [0011]      FIG. 1  is a top view of a torque clutch of a typical power tool; 
           [0012]      FIG. 2  is a perspective view of a power tool constructed in accordance with the teachings of the present invention; 
           [0013]      FIG. 3  is an enlarged view of the torque clutch according to a first embodiment; 
           [0014]      FIG. 4  is another enlarged view of the torque clutch according to a first embodiment; 
           [0015]      FIG. 5  is a sectional view of the torque clutch of  FIG. 2 ; 
           [0016]      FIG. 6  is an enlarged view of the torque clutch according to a second embodiment; 
           [0017]      FIG. 7  is a sectional view of the torque clutch of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    With reference to  FIG. 2 , a power tool constructed in accordance with the teachings of the present invention comprises a housing  4  containing a motor (not shown), and a handle  8  with a trigger assembly  9  mounted thereon. A battery  10  is detachably mounted on the bottom of the handle  8 . A chuck  3  is disposed in front of the housing  4 . A bit (not shown) is generally coaxial with the motor, which is detachably attached to the chuck  3  and is driven by the motor. A rotatable torque clutch  1  is supported on the housing  4 , and positioned between the chuck  3  and the housing  4 . 
         [0019]    As shown in  FIG. 3  to  FIG. 6 , the torque clutch  1  is formed in one piece. The torque clutch includes a scale portion  7  close to one end of the housing  4 . As shown in  FIG. 4 , the scale portion  7  includes a work mode scale portion  7   a  and a torque setting scale portion  7   b,  which are used to set the tool on the appropriate work mode or torque level for the project. Numbers and the marks on the scale portion  7  form the scale  12 . Several depressed elements  2   a  are evenly spaced and separated by raised elements  2   b,  and arranged at intervals on the torque clutch  1 , forming a grip portion  2 . This grip structure increases the contact area of the hand and the grip portion  2  providing better grip when the user holds and rotates the torque clutch  1  to the desired position. 
         [0020]    In the present embodiment, the torque clutch  1  is preferably constructed from transparent material, including, for example, any suitable plastic. The external surface of torque clutch  1  may covered by opaque coating, while the scale  12  remains transparent. Optionally, the scale  12  is covered by opaque coating, and the area surrounding the scale is transparent. The opaque coating on the torque clutch or scale may be a paint, lacquer, or film. The opaque coating or film may cover the external surface or inner surface of the torque clutch  1 . Alternatively, the numbers and marks of the scale  12  may be cut out or hollowed. 
         [0021]    As shown in  FIG. 3 , there is an indicator  5  on the housing  4 , which may be any suitable two-dimensional shape, transparent or cut out. The midline of the indicator  5  and the axial symmetrical axis of the power tool are in the same plane. The indicator  5  meets at the scale  12  on the torque clutch  1 , thereby designating the work mode or torque value of the power tool when the torque clutch is rotated to the desired setting. 
         [0022]    In order to illuminate the numbers and/or marks of the scale, preferably a light source  6  is mounted within the housing  4 , positioned opposed to the indicator  5 . In an alternative embodiment, the light source  6  may be mounted within the torque clutch  1 , which is positioned opposed to the scale  12  of torque clutch  1 . The light source  6  may any suitable light source for use within a power tool. Preferably, the light source is an LED. 
         [0023]    In  FIG. 5 , the light source  6  is triggered by the trigger assembly  9  for controlling the motor operating the power tool. The light source  6  is lit when the user presses the trigger assembly  9  and the power tool is turned on for use. The light source  6  then illuminates the numbers and/or marks of the scale  12  clearly indicating the work mode or the torque setting of the power tool when the operating environment is dark or dimly lit. 
         [0024]      FIG. 6  and  FIG. 7  show a second embodiment of the present invention, wherein the housing  4  includes a button  11 , which is connected with the light source  6  by an electrical connection or printed circuit board  13 . The light source  6  will be lit by the user pressing the button  11 . Again, the light source  6  is useful for clearly reading the gradients for the work mode or the torque setting on the torque clutch  1 . 
         [0025]    In yet another possible embodiment, rather than having a light source mounted in the housing  4 , the scale  12  and the indicator  5  may be covered by a light-absorbing, self illuminating coating. The alternative illumination source may also include a fluorescent or reflective material or paint. The torque clutch is illuminated when the tool is placed in a high light environment. The scale  12  of torque clutch  1  shines or reflects absorbed light, providing the user with the ability to read the work mode and torque level indicators when using the power tool in dimly lit or dark working conditions.