Abstract:
A power tool has a body portion, a head portion, and a motor located in the body portion. A connecting spindle arranged within the head portion is driven by the motor for rotation. A first replaceable spindle is releasably connectable to the connecting spindle. The first replaceable spindle has a first output portion adapted for mounting a working head. A second replaceable spindle is additionally provided which is also releasably connectable to the connecting spindle. Two different working heads are mounted on the first output portion and the second output portion, respectively, to thereby provide a multi-function power tool.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    This application claims the benefit of CN 200910183793.4, filed on Aug. 11, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    This disclosure generally relates to power tools and, more particularly, relates to a multi-function power tool. 
         [0003]    There currently exists many types of power tools, such as electric drills, angle grinders, sanding machines, and the like. Generally, different types of power tools can achieve different functions, and one kind of power tool often has only a single function. For example, an electric drill is used for drilling, an angle grinder is used for coarsely grinding metal, wood and other objects, and a sanding machine is used for finely grinding the wood surface. Therefore, at some places with architectural decoration, a users usually prepares a number of different types of power tools to achieve different functions in operation. 
       SUMMARY 
       [0004]    The following describes a multi-function power tool having replaceable spindles by which the power tool can achieve different functions such as grinding, polishing, etc. More particularly, the described power tool includes a body portion, a head portion, and a motor located in the body portion. A connecting spindle is arranged within the head portion and driven by the motor for rotation and a first replaceable spindle can be releasably fixed to the connecting spindle. The first replaceable spindle has a first output portion adapted for mounting a working head. 
         [0005]    The multi-function power tool further includes a retaining assembly used for fixing the first replaceable spindle to the connecting spindle and the first replaceable spindle further comprises an upper portion which is connectable to the retaining assembly. 
         [0006]    The multi-function power tool may additionally comprise a second replaceable spindle which can be releasably fixed to the connecting spindle. The second replaceable spindle has an upper portion, which is the same as the upper portion of the first replaceable spindle, and a second output portion where two different working heads are mounted on the first output portion and the second output portion, respectively. 
         [0007]    As will become apparent, the hereinafter described, multi-function power tool can be provided with many different working heads for completing various functions by replacing the first and second replaceable spindles mounted on the connecting spindle and optionally mated with different working heads. In addition, with the retaining assembly, the replaceable spindles can be mounted on or released from the power tool quickly, and the operation is convenient and fast, without any use of other tools. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The subject multi-function power tool will be further described with reference to the accompanying figures, in which: 
           [0009]      FIG. 1  is a perspective view of a first exemplary embodiment of a multi-function power tool constructed according to the description that follows; 
           [0010]      FIG. 2  is an exploded view showing some of the structures of the power tool shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a top view of the power tool shown in  FIG. 1 ; 
           [0012]      FIG. 4  is a sectional view of the power tool along the line A-A shown in  FIG. 3 , wherein the replaceable spindle is located at a position such that the replaceable spindle is retained on the connecting spindle; 
           [0013]      FIG. 5  is a sectional view of the power tool along the line A-A shown in  FIG. 3 , wherein the replaceable spindle is located at a position such that the replaceable spindle can be released from the connecting spindle; 
           [0014]      FIG. 6A  is a perspective view of a second exemplary embodiment of a multi-function power tool constructed according to the description that follows; 
           [0015]      FIG. 6B  is an exploded view showing some of the structures of the power tool shown in  FIG. 6A ; 
           [0016]      FIG. 6C  is a sectional view of the power tool shown in  FIG. 6A  in the longitudinal direction; 
           [0017]      FIG. 7A  is a perspective view of a third exemplary embodiment of a multi-function power tool constructed according to the description that follows; 
           [0018]      FIG. 7B  is an exploded view showing some of the structures of the power tool shown in  FIG. 7A ; 
           [0019]      FIG. 7C  is a sectional view of the power tool shown in  FIG. 7A  in the longitudinal direction; 
           [0020]      FIG. 8A  is a perspective view of a fourth exemplary embodiment of a multi-function power tool constructed according to the description that follows; 
           [0021]      FIG. 8B  is an exploded view showing some of the structures of the power tool shown in  FIG. 8A ; and 
           [0022]      FIG. 8C  is a sectional view of the power tool shown in  FIG. 8A  in the longitudinal direction. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Now referring to  FIG. 1  and  FIG. 2 , a multi-function power tool  10  constructed according to one of the preferred embodiments of the subject invention includes a body portion  20  and a head portion  30 . A motor  21  is located in the body portion  20  and a switch  22 , which can be operated by the user to control the starting and stopping of the motor  21 , is installed outside of the body portion  20 . In this embodiment, the power tool  10  includes an AC power line  23  extending from the body portion  20  to supply the motor with an external AC power. However, it is also possible to supply the motor by other means, such as DC power. A working head  40  is installed on the head portion  30 . With an inner motion transmission mechanism, the motion of the motor  21  is transmitted to the working head  40  so as to drive the working head  40  to operate working objects associated with the working head  40 . In this embodiment, the body portion  20  and the head portion  30  can be two separate components or a single component integrated with each other. 
         [0024]    Referring to  FIGS. 2-5 , the motor  21  includes a motor output shaft  211  which has an axis  213  and a gear  212  is formed on one end of the motor output shaft  211  which is closest to the head portion  30 . The head portion  30  includes a connecting spindle  31  which has a longitudinal axis  214 , the longitudinal axis  214  is generally perpendicular to the axis  213  of the motor output shaft, and the connecting spindle  31  is hollow in the interior thereof. A bevel gear  32  is formed on the lower portion of the connecting spindle  31 . The bevel gear  32  can be engaged with the gear  212  on the motor output shaft  211 , so that the rotation of the motor output shaft  211 , upon the motor  21  being turned on, will be transmitted to the bevel gear  32  via the mutually engaged gear transmission portions, and thereby the bevel gear  32  will drive the connecting spindle  31  to rotate. A retaining assembly  33  is arranged on the upper portion of the connecting spindle  31  for retaining an inner shaft  34  within the connecting spindle  31 . When the inner shaft  34  is retained within the connecting spindle  31 , the inner shaft  34  can rotate together with the connecting spindle  31 , and can further drive the working head  40  to rotate since the working head  40  is arranged on the lower end of the inner shaft  34 . Therefore, the motion of the motor can be transmitted to the working head  40  by the mutually engaged gear transmission portions, the connecting spindle  31 , and the inner shaft  34  retained in the connecting spindle  31 . The inner shaft  34  can be releasably retained within the connecting spindle  31 , and the user can replace the inner shaft  34  as desired. The inner shaft  34  includes an upper connection portion  341  and a lower connection portion  342 . The retaining assembly  33  will be described in detail below. 
         [0025]    The retaining assembly  33  comprises a pair of clamping legs  35  arranged oppositely, and each of the clamping legs  35  includes a cylindrical protrusion  351  at the upper portion thereof, a through-hole  352  at the middle portion thereof, and a hook-shaped protrusion  353  at the lower portion thereof. A compression spring  36  is installed on the cylindrical protrusions  351  in a manner such that the spring  36  is connected to the cylindrical protrusion  351  of each clamping leg  35  at two ends thereof, respectively. The upper portion of the connecting spindle  31  has a pair of extended elements  311  which are arranged oppositely and provided with a cavity therebetween for receiving the retaining assembly  33 . The pair of the extended elements  311  is also provided with holes  312  at the position corresponding to the through-holes  352 . A pair of engaging pins  37  can extend through the holes  312  in the extended elements and the through-holes  352  in the clamping legs  35  so that the clamping legs  35  can be attached to the connecting spindle  31 . A compression spring  38  surrounds the outside of the clamping legs  35  with the lower end thereof abutting against the end surface of a structural element  39  within the head portion and the upper end thereof connected to a lower protrusion  51  on an actuator  50 . The actuator  50  also includes a cap-like portion  52  projecting to the outside of the head portion  30  to allow for touching by the user and a step portion  53  for restricting the actuator  50  within the head portion  30  so that the actuator  50  can not be completely disengaged from the head portion  30 . The elastic force of the compression spring  38  drives the cap-like portion  52  to move outwardly toward the external of the head portion  30 . The actuator  50  includes an interior cavity  54  for receiving the upper portions of the clamping legs  35 , and a generally conical inner surface  55  is formed in the interior cavity  54 . 
         [0026]    The elastic force of the compression spring  36  will drive the pair of clamping legs  35  to rotate inwardly around the engaging pins  37  after the inner shaft  34  is pushed upward into the clamping legs  35 , so that the hook-shaped protrusions  353  of the clamping legs lock the upper connection portion  341  of the inner shaft which has a groove  343  for receiving the hook-shaped protrusions  353 . A gasket  345  and a spring washer  346  are further arranged between the end surface of the step  344  of the inner shaft and the lower end surface  313  of the connecting spindle. The elastic force of the spring washer  346  may pull downwardly the inner shaft  34  so that the head  347  thereof abuts against the hook-shaped protrusions  353  of the clamping legs. With the mating of the hook-shaped protrusions  353  of the clamping legs and the groove  343 , as well as the elastic effect of the spring washer, the inner shaft  34  can be fixedly retained in the connecting spindle  31 , as shown in  FIG. 4 . 
         [0027]    When the inner shaft  34  needs to be removed from the connecting spindle  31  as desired, the actuator  50  is firstly pressed to move downwardly by overcoming the elastic force of the spring  38 , and the conical inner surface  55  of the actuator  50  also moves downwardly and acts on the upper end of the clamping legs  35  to make the clamping legs  35  rotate outwardly around the engaging pins  37  so that the hook-shaped protrusions  353  are separated from each other and disengaged from the groove  343  on the inner shaft, as shown in  FIG. 5 . In this way, the inner shaft  34  can be released from the retaining assembly  33  to be removed from the connecting spindle  31 . 
         [0028]    In the embodiment described above, only one kind of the retaining assembly is described, however, those skilled in this art will understand out that other retaining assemblies may be used to retain the inner shaft within the connecting spindle. The retaining assembly is also not limited to the described mechanical structure and may be other assemblies capable of performing the function of retaining the spindle, such as through the use of magnetic force and the like. 
         [0029]    In the embodiment illustrated in  FIG. 1 , the working head  40  is a grinding wheel structure mated with the lower connection portion  342  of the inner shaft  34 , so that the power tool  10  can be used as an angle grinder for angle grinding when the inner shaft  34  is retained in the connecting spindle  31 . Therefore, the power tool  10  can achieve many different functions by replacing the inner shaft  34  with different output portions which can be mated with different working heads. 
         [0030]      FIGS. 6A-6C  illustrate another embodiment, wherein the power tool  100  is an orbital sander. The upper connection structure  102  of the inner shaft  101  may not be changed, but the lower connection structure  103  is eccentrically connected with a chassis  107  via a bearing  104 , a balance block  105  and a locking nut  106 , so as to achieve the function of the orbital sander. 
         [0031]      FIGS. 7A-7C  illustrate a further embodiment, wherein the power tool  200  is a rotary sander. The upper connection structure  202  of the inner shaft  201  may not be changed, but the lower connection structure  203  is coaxially equipped with a chassis  204 , so as to achieve the function of the rotary sander. 
         [0032]      FIGS. 8A-8C  illustrate a still further embodiment, wherein the power tool  300  is an electric rasper. The upper connection structure  302  of the inner shaft  301  may not be changed, but the lower connection structure  303  is equipped with a rasping head  304  via a connection mechanism, so as to achieve the function of the electric rasper. 
         [0033]    In summary, the inner shafts in above embodiments have the same upper connection structures which enable the inner shaft in each embodiment to be releasably retained in the connecting spindle by the retaining assembly  33 , and different lower connection structures which enable the inner shaft in each embodiment to be equipped with different working heads so as to obtain a power tool with various functions. Certainly, those skilled in the art will understand that different adapters can be arranged between the lower connection structure of the inner shaft and the working head, so that one inner shaft can be connected with many various working heads to obtain a power tool with various functions. 
         [0034]    The disclosed specific embodiments are not intended to be limiting. Rather, those skilled in the art will appreciate that other alternative or modified embodiments can be adopted and these alternative or modified embodiments will be regarded as falling within the scope of the invention as defined by the following claims.