Abstract:
The present invention relates to a power tool comprises an adjusting mechanism, the adjusting mechanism comprising a station element defining at least a first engaged member, and an adjusting member rotated about a axis and driving the first engaged member to move elastically along the axis, wherein a frequency increase mechanism is disposed between the adjusting member and the station element, the frequency increase mechanism coupled to the first engage member, the frequency of the elastic moving of the first engage member increases when the adjusting member rotates about the axis. Because the adjusting mechanism can increase the sound frequency, so it can make precision and dense sound and remind of the operator when the adjusting member rotated.

Description:
RELATED APPLICATIONS 
     This application claims the filing benefit of International Patent Application No. PCT PCT/CN2009/070274, filed Jan. 22, 2009, which claims the filing benefit of Chinese Patent Application No. 200810005373.2 filed Jan. 31, 2008, the contents of both are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a power tool, and more particularly to a power tool such as an electric drill, a hammer, a router, a planer etc which suitably of used for rotating an adjustment member of the power tool to different situation during the operation of the power tool. 
     BACKGROUND OF THE INVENTION 
     A power tool can be adjusted by rotating and adjusting a control member to accommodate different situation during the operation of the power tool. For example, a torque adjusting sleeve of an electric drill can be rotated and adjusted to different output torques according to the operating load of the electric drill, a chuck of a hammer can be rotated and adjusted for adapting different bits, and a depth ruler of a router can be rotated and adjusted for suit different cutting depth, a planer is provided with a switch handle which is used for rotating and adjusting the distance between a front shoe and a rear shoe according to the cutting thickness of the planer. In fact, the operator hope to be reminded by some indicator when the adjustment member is rotating or adjusting during the operation, in case the operator performs incorrect operation and be not aware of the dangers. In general, the power tool works in the conditions accompanying with great vibration, the adjustment member of the power tool is easy to loose or reverse from its original position as the result of the vibration. It will be very easy to make dangers if the operator didn&#39;t get the caution in time. A power tool including a sound indicator for a adjustment member was disclosed in prior art, the frequency of the sound occurs at each revolution of the adjustment member is less than 25, the frequency of the sound is too lower to cause the operator to pay attention. 
     U.S. Pat. No. 6,805,206 discloses a hammer which includes a tool or a bit mounted on a spindle of the hammer, the hammer comprises a pair of ratchet wheels which enable impacting each other to cause sounds to remind of the operator when the tool or bit to be rotated to a determined orientation. As we know, the power tool is generally used for decorating or building and the environments full of noise, and the power tool itself also make a noise in use, the sound frequency of ratchet wheels of the hammer is about 20 (the times of a sound occurs at each revolution is about 20), the sound frequency is too lower to achieve the effect of remind. 
     SUMMARY OF THE INVENTION 
     One technical problem to be solved by the present invention is to provide a power tool which comprises an adjusting member that makes dense sounds when the adjusting member rotated about an axis. 
     A technical solution of the present invention is to provide a power tool comprising an adjusting mechanism, the adjusting mechanism comprises a station element defining at least a first engaged member and an adjusting member rotated about an axis and driving the first engaged member to move elastically along the axis, wherein a frequency increase mechanism is disposed between the adjusting member and the station element, the first engage member coupled to the frequency increase mechanism, the frequency of the elastic moving of the first engage member increases when the adjusting member rotates about the axis. 
     Typically the first engaged member moving elastically more than 40 times at each revolution of the adjusting member. 
     Typically the adjusting member provide an internal gear, the frequency increase mechanism comprises at least a group of speed increase mechanism, the speed increase mechanism coupled with the internal gear and the first engage member respectively. 
     Preferably the first engaged member formed as a metal spring tab with two ends, one end of the metal spring tab coupled with the station element fixedly, the other end engaged with the speed increase gear mechanism. 
     Preferably the station element defining a guide groove with two ends thereof one end is closed and the other end is opened, the first engaged member is movably received in the guide groove, one end of the first engaged member coupled with the closed end of the guide groove via a spring, the other end extend out off the guide groove and engaged with the speed increase gear mechanism. 
     Preferably a friction member is located between the speed increase gear mechanism and the station element which increase the friction force between the station element and speed increase gear mechanism. 
     In a preferred embodiment, the frequency increase mechanism comprises a ratchet ring, which located in the internal circumference of the adjusting member, the ratchet ring provide with more than 40 teeth disposed in the interior surface of the ratchet ring. 
     Preferably the first engaged member comprises a metal spring tab with two ends, one end of the metal spring tab couple with the station element fixedly, the other end engaged with the ratchet ring. 
     Preferably the station element defining a guide groove with two ends thereof one end is closed and the other end is opened, the first engaged member is movably received in the guide groove, one end of the first engaged member coupled with the closed end of the guide groove via a spring, the other end extend out off the guide groove and engaged with the ratchet ring. 
     In a preferred embodiment, the frequency increase mechanism comprises at least a second engage member which located on the station element, there are a phase difference between the second engage member and the first engage member, the adjusting member drives the second engage member and the first engage member in turn to moving elastically. 
     Preferably the frequency increase mechanism comprising two second engage members. 
     Preferably the phase difference between each proximate engage members of the first engage member and the second engage members is 5 degree. 
     Because the power tool of the invention provides an adjusting mechanism for increases the sound frequency, it makes precision and dense sound and remind of the operator when the adjusting member rotated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be further described with reference to the torque sleeve of a drill together with the attached drawings, wherein: 
         FIG. 1  is a front view of a torque sleeve portion of a drill according to a first preferred embodiment of the present invention; 
         FIG. 2  is a cross-sectional view taking along line A 1 -A 1  of  FIG. 1 ; 
         FIG. 3  is an exploded view of  FIG. 1 ; 
         FIG. 4  is a schematic view of a spring member according to a second preferred embodiment of the present invention; 
         FIG. 5  is a schematic view of the third preferred embodiment of the present invention; 
         FIG. 6  is a schematic view of the fourth preferred embodiment of the present invention; 
         FIG. 7  is a partial enlarged view part A of  FIG. 6 ; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a drill comprises a housing  1 , a motor (not shown) contained in the housing  1 , a shaft  2  is rotatablely drived by the motor, a torque sleeve  3  is rotatablely mounted on the housing  1  and has an axis X 1 . A flange  32  is formed on the interior of the torque sleeve  3 , the torque sleeve  3  is divide into a front part  32   a  and a rear part  32   b  by the flange  32 . A helix sleeve  4 , a spring  5  and a clutch member  6  is received in the torque sleeve  3 , the helix sleeve  4  coupled with the torque sleeve  3  via thread, the first end of the spring  5  press against the helix sleeve  4  and the second end of the spring  5  press against the clutch member  6 . The helix sleeve  4  moves along the extended direction of the axis X 1  when the torque sleeve  3  rotates about the axis X 1 , the clutch member  6  is biased by the spring  5 . The compression deformation of the spring  5  is changed when the torque sleeve  3  rotate about the axis X 1 , so the force pressed on the clutch member  6  is changed, such that the output torque of the shaft  2  of the drill  2  is changed. 
     Referring to  FIG. 2  and  FIG. 3 , a station element  7  and a internal gear  8  are located in the front part  32   a  of the torque sleeve  3 , the station element  7  is coupled with the housing  1  and the internal gear  8  is fixedly engaged with the torque sleeve  3 . A group of speed increase mechanism  9  is disposed on the station element  7 . In the first preferred embodiment of the present invention, the group of speed increase mechanism  9  comprises a first gear  92  which engaged with the internal gear  8 , a second gear  94  which engaged with the first gear  92 , a third gear  96  which moves with the second gear  94  at the same angular speed, a fourth gear  98  which engaged with the third gear  96 , and a ratchet wheel  100  which moves with the fourth gear  98  at the same angular speed, the ratchet wheel  100  has a plurality of teeth formed on the outer surface along circumference of the ratchet wheel  100 , a friction member  18  is located between the ratchet wheel  100  and the station element  7 . A L-shaped slot  72  disposed on the station element  7 , a metal spring tab  10  is generally L-shaped disposed in the slot  72 , one end of the metal spring tab  10  connect with the station element  7  fixedly via a press member  12 , the other end of the metal spring tab  10  is a free end which contact with the ratchet wheel  100  elastically, it causes an elastically impact between the ratchet wheel  100  and the metal spring tab  10  when the ratchet wheel  100  rotates over each tooth of the a plurality of teeth, such that a clear sound is made at the same time. It is easy to those skilled in the art that replace the metal spring tab  10  by other elastic members according to the present invention. 
     Referring to  FIG. 4 , the station element  7  provided with a guide groove  74  which has two ends with one end is closed and the other end is opened, a spring member comprises an insert member  14  is movably received in the guide groove  74  and a spring  16  coupled with the close end with its one end and connect with the insert member  14  with its other end, the insert member  14  has a free end which is formed as a V-shaped tip which press against the ratchet wheel  100  under the elasticity of the spring  16 , The ratchet wheel  100  turned over each tooth, there will make an elastic impact between the ratchet wheel  100  and the insert member  14 , and a sound will sent out at the same time according to each elastic impact. 
     The ratchet wheel  100  rotates at a high speed and impacts with the spring  16  of the spring F\member When the torque sleeve  3  rotates about the axis X 1 , a continuous and exact sound is made simultaneity. If the sound frequency is more than 40, it conform to the ergonomics and cause the operator to pay attention, so it is better to remind of the operator. In the three embodiment of the present invention, about 200 times impact will be made between the ratchet wheel  100  and the spring member when the torque sleeve  3  rotate over a circle. However, it is easy to those skilled in the art to change the frequency of the impact between the ratchet wheel  100  and the spring member by setting different transmission rate of the speed increase mechanism  9 . Referring to  FIG. 3 , in the first embodiment of the present invention, a friction member  18  is located between the ratchet wheel  100  and the station element  7  which increase the friction between the speed increase mechanism  9  and the station element  7 , such that the torque sleeve  3  is locked on the speed increase mechanism  9  and prevented from reversing when the torque sleeve  3  is not in use. 
     According to the design of the present invention, It is easy to those skilled in the art to make other mechanism for increasing the sound frequency. Referring to  FIG. 5 , The torque sleeve  3  has a ratchet ring  19  disposed on interior surface along its circumference of the torque sleeve  3 , the ratchet ring  19  has a plurality of teeth disposed on the inner surface, 90 teeth is perfect in this embodiment of present invention which impacts with a spring member  20  disposed on the station element  7  when the torque sleeve  3  rotate about the axis X 1 , thereof the station element  7  provide with a guide groove (not shown) similar with the guide groove  74 , the spring member  20  is received in the guide groove. About 90 times impact will be made between the ratchet ring  19  and the spring member  20  when the torque sleeve  3  rotate over a circle. It is easy to those skilled in the art to make different ratchet ring which have different number of tooth. The mechanisms that make the frequency of the sound more than 40 is considered within the scope of this invention. 
     Further referring to  FIG. 6  and  FIG. 7 , a ratchet ring  21  is disposed on the interior surface along its circumference of the torque sleeve  3 , the ratchet ring  21  has a plurality of teeth disposed on the inner surface, the number of the teeth is less than 25, a plurality of spring members  22  are respectively located in the different position of the station element  7 , the spring members  22  are disposed according to a given phase difference, an optimal given phase difference should satisfy a measure value, as well as the angle between every two proximate teeth of the ratchet ring  21  is approximately equal to the product of the number of the spring members and the given phase. According to the fourth preferred embodiment of the present invention, there are three spring members  22 , 23 , 24  disposed on the station element and the total 24 teeth are disposed on the ratchet ring, the phase difference between every two proximate spring members can be calculated according to foregoing method, as well as use the 360 degree divide the number 24 of the teeth and get the angle value between every two proximate teeth of the ratchet ring  21 , and then use the angle value divide the number 3 of the spring members get the phase difference of every two proximate spring members. In this embodiment the phase difference of every two proximate spring members is 5 degree. The spring members  22 , 23 , 24  impact with the same tooth of ratchet ring in turn when the torque sleeve  3  rotates about the axis X 1 , so total 72 times impact will be made between the ratchet ring  21  and the spring member  22 , 23 , 24  when the torque sleeve  3  rotate over a circle. 
     The phase difference described above can be considered the distance L 1  between the free end of the first spring member  21  and the second spring member  22  which is approximately equal to the distance L 2  between the free end of the second spring member  22  and the third spring member  23 , the sum of L 1  and L 2  is approximately equal to the distance L between every two teeth. 
     It will be apparent to those skilled in this art that various modifications or changes can be made to the elements of the present invention without departing from the spirit of this invention. Accordingly, all such modifications and changes also fall within the scope of this invention.