Patent Publication Number: US-2016243634-A1

Title: Reciprocating tool

Description:
TECHNICAL FIELD 
     The present invention relates to a reciprocating tool such as a jigsaw and more specifically relates to a reciprocating tool providing a cutting blade with reciprocating movement by means of rotation of a motor. 
     BACKGROUND ART 
       FIG. 9  illustrates a vertical cross-sectional structure of a conventional reciprocating tool converting rotation of a rotating shaft of a motor serving as an electric machine into reciprocating movement to cut an object. As illustrated in  FIG. 9 , a jigsaw ‘a’ as an example of the reciprocating tool includes a motor ‘b’ serving as a driving portion and a gear c serving as a decelerator. To a position on a side surface of this gear ‘c’ close to an outer circumferential portion of the side surface, a roller-shaped connecting piece ‘d’ is attached. This connecting piece d is rotatable centering on a support shaft ‘e’ of the gear c. 
     The jigsaw a also includes a plunger g driving a blade ‘f’ serving as a cutting blade in an up-down direction. This plunger ‘g’ is provided with a connector ‘h’ having a U-shaped cross-section including a pair of upper and lower guides ha and hb which engages with the connecting piece d. 
     This connector h causes the rotating movement of the connecting piece d to be converted into reciprocating movement of the plunger g in a vertical direction. The blade f serving as a saw blade is attached to a lower end of the plunger g, and by moving this blade f in manner of a saw, the object can be cut. Also, to restrict vibration caused by the reciprocating movement of the plunger g, the gear c is provided with a balance weight ‘i’ adapted to move in an opposite phase to that of the plunger g. An example of such a reciprocating tool is a jigsaw described in Patent Document 1. 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Patent No. 4525532 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, since a spur gear is used as the gear c in the jigsaw a, the gear c is installed on an upper side of a main body. For this reason, a length of the plunger g connected with the gear c via the connecting piece d extends to generally cause the centroid of the main body to be located at a high position. A cutting reaction force acts on the blade f at the time of operation. Accordingly, in a case in which a distance between the blade f and the centroid increases, moment acting on the centroid increases, which causes the main body to vibrate easily. In addition, at the time of acceleration and deceleration of the motor b due to cutting load, vibration in a right-left direction is generated by rotational reaction force of the motor b. 
     The present invention has been achieved to solve the above problems. An object of the present invention is to provide a reciprocating tool enabling reduction in vibration and improvement in operability. 
     Means for Solving the Problems 
     A reciprocating tool of the present invention includes: a main body; a power source provided in the main body; a driving gear provided in the power source; planetary gears connected to the driving gear; a ring gear connected to the planetary gears; a movement converting portion converting rotation of the ring gear into reciprocating movement; a tip end tool driven by the movement converting portion; and a balance weight restricting vibration generated by the reciprocating movement. The ring gear is rotated around a rotation center by power of the power source. 
     According to an aspect of the present invention, a support shaft rotatably supporting the planetary gears is fixed to the main body. 
     According to another aspect of the present invention, the driving gear and the ring gear are rotated in opposite directions to each other. 
     According to another aspect of the present invention, a center of the driving gear and a center of an inner circumference of the ring gear are coaxial. 
     According to another aspect of the present invention, each support shaft of the planetary gear is arranged on upper and lower sides of the driving gear with the driving gear interposed therebetween and are fixed to the main body. 
     According to another aspect of the present invention, when a ratio of inertia moment at an assembled part rotated in an equal direction to that of an electric motor to inertia moment at an assembled part rotated in an equal direction to that of the ring gear is y, and a rotational speed ratio of the respective parts is x, 0.46x≦y≦1.38x is established. 
     According to another aspect of the present invention, 0.73x≦y≦1.11x is established. 
     According to another aspect of the present invention, 0.82x≦y≦1.01x is established. 
     According to another aspect of the present invention, a part of the ring gear in a circumferential direction thereof is provided with a thick eccentric cam portion formed to cause the center of the inner circumference and a center of an outer circumference of the ring gear to be eccentric. 
     According to another aspect of the present invention, the outer circumference of the ring gear is provided with an orbital cam adapted to cause the tip end tool to swing in a front-back direction. 
     Effects of the Invention 
     The present invention can provide a reciprocating tool enabling reduction in vibration and improvement in operability. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a vertical cross-sectional view of a jigsaw according to an embodiment of the present invention in which a plunger is located at a top dead center; 
         FIG. 2  is a cross-sectional view of a main part along the line A-A in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of a main part along the line B-B in  FIG. 1 ; 
         FIG. 4  is a vertical cross-sectional view of the jigsaw according to the embodiment of the present invention in which the plunger is located at a bottom dead center; 
         FIG. 5  is a cross-sectional view of a main part along the line A-A in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of a main part along the line B-B in  FIG. 4 ; 
         FIG. 7  is a graph illustrating relationship between a ratio of inertia moment at planetary gear&#39;s input and output portions and torque acting on a normalized housing; 
         FIG. 8  is a graph illustrating relationship between a rotational speed ratio of an input shaft and an output shaft and the ratio of inertia moment at the planetary gear&#39;s input and output portions; and 
         FIG. 9  is a vertical cross-sectional view illustrating a conventional jigsaw. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A jigsaw cutting an object will be described with reference to the drawings as a reciprocating tool according to an embodiment of the present invention. 
       FIG. 1  is a vertical cross-sectional view illustrating an entire structure of a jigsaw  11  according to an embodiment of the present invention, and a blade  17  illustrated in the figure is located at an uppermost position.  FIGS. 2 and 3  illustrate cross-sectional structures at different positions of the jigsaw  11 .  FIG. 4  is a vertical cross-sectional view illustrating an entire structure of the jigsaw  11 , and the blade  17  illustrated in the figure is located at a lowermost position.  FIGS. 5 and 6  illustrate cross-sectional structures at different positions of the jigsaw  11 . 
     Examples of an object  10  ( FIGS. 1 and 4 ) to be cut by the jigsaw  11  are wood, a soft steel plate, and stainless steel. As illustrated in  FIG. 1 , the jigsaw  11  includes a main body  12  forming an outer shell. The main body  12  includes a first cylindrical portion  13  extending in a horizontal direction, a second cylindrical portion  14  extending upward from an end portion of the first cylindrical portion  13 , and a handle portion  15  connecting the end portion of the first cylindrical portion  13  with an end portion of the second cylindrical portion  14 . 
     Here, the horizontal direction means a right-left direction in  FIG. 1 . A center line of the first cylindrical portion  13  and a center line of the second cylindrical portion  14  intersect with each other. Also, a front surface of the second cylindrical portion  14  is provided with an opening portion  14   a . This opening portion  14   a  is covered with a cover  14   b  attached to the front surface of the second cylindrical portion  14 . Also, a lower portion of a part at which the first cylindrical portion  13  and the second cylindrical portion  14  intersect is provided with a base portion  12   a  to be mounted on a surface  10   a  of the object  10  to move on the surface  10   a.    
     In the first cylindrical portion  13  is provided an electric motor  16  serving as a power source outputting a driving force. The electric motor  16  includes a stator, a rotor, and a rotating shaft  16   a  rotated integrally with the rotor. By power of the electric motor  16 , the blade  17  serving as a tip end tool is reciprocated via planetary gears  22  of a planetary gear mechanism serving as a decelerating mechanism. The rotating shaft  16   a  serving as an output portion of the electric motor  16  is arranged in the first cylindrical portion  13  along an axial direction of the first cylindrical portion  13  of the first cylindrical portion  13 . The rotating shaft  16   a  is rotatably supported by a first bearing  20  and a second bearing  20 A arranged on a front side and a backside in the axial direction. The rotating shaft  16   a  is provided with a fan  18  cooling the electric motor  16  and a driving gear  19 . A gear holder  21  is provided at the part at which the first cylindrical portion  13  and the second cylindrical portion  14  intersect, and the first bearing  20  is attached to this gear holder  21 . 
     As illustrated in  FIGS. 1 to 3  and  FIGS. 4 to 6 , to the gear holder  21  is rotatably attached via support shafts  23  and  23  a pair of upper and lower planetary gears  22  and  22  meshing with the driving gear  19 . That is, the support shafts  23  and  23  rotatably supporting the planetary gears  22  and  22  are fixed to the main body  12  via the gear holder  21 . Thus, a rotating direction of the driving gear  19  and a rotating direction of a ring gear  27  are opposite directions to each other. Accordingly, as described below, rotational moment is cancelled out at the time of driving of the electric motor  16 , yawing of the main body  12  is restricted, and reduction in vibration is achieved. 
     In the second cylindrical portion  14  is provided a partition member  24  to be opposed to the gear holder  21 . The partition member  24  is provided with a circular opening portion  25  centering on the driving gear  19 . Also, in the opening portion  25 , the bottomed cylindrical ring gear  27  having at an inner circumference thereof an internal tooth portion  26  to mesh with the planetary gears  22  and  22  is rotatably provided via a needle bearing  28  arranged at a part (a base portion side) of an outer circumference of the ring gear  27 . 
     A part of the ring gear  27  in a circumferential direction thereof (a part of an outer circumference on a tip end side) is provided with an eccentric cam portion  30  adapted to drive an orbital cam  29   a  of an orbital mechanism  29  described below. To be more specific, an outer shape of the ring gear  27  is circular, and a circular hollow portion  27   a  is provided inside the ring gear  27  in an eccentric state (refer to  FIG. 2 ). That is, a center of the inner circumference and a center of the outer circumference of the ring gear  27  are mutually eccentric. As a result, the part of the ring gear  27  in the circumferential direction thereof is provided with a thick portion serving as the eccentric cam portion  30 . Also, the inner circumference in the hollow portion  27   a  is provided with the internal tooth portion  26  to mesh with the planetary gears  22 . 
     As illustrated in  FIG. 2 or 5 , the orbital cam  29   a  is provided with an elliptic opening portion  31  sliding in contact with an upper surface portion and a lower surface portion of an outer circumferential surface of the ring gear  27 . A vertical diameter of this opening portion  31  is approximately equal to an outside diameter of the ring gear  27  while a horizontal diameter of the opening portion  31  is as long as to allow rotation of the ring gear  27  doing eccentric movement. 
     The orbital cam  29   a  is made of a rigid thin plate material such as a metal plate. To guide movement of the orbital cam  29   a , guide pins  32  are provided in the partition member  24 , and guide grooves  33  are provided in the orbital cam  29   a  along an up-down direction to slidably engage with the guide pins  32 . 
     To restrict vibration of the main body  12  along with reciprocating movement of a plunger  34  provided in the second cylindrical portion  14  in the up-down direction, a balance weight  36  is attached to a front portion of the ring gear  27  via a ring cam  35 . The ring cam  35  has an approximately equal outer shape to that of the ring gear  27 . However, the ring cam  35  is provided with no internal tooth portion  26  as the ring gear  27 . 
     A circular covering portion  38  is fixed to an opening portion  37  of the ring cam  35 , and the covering portion  38  including the ring cam  35  is fixed to a front end portion of the ring gear  27  by a bolt  39 . In the covering portion  38  including the ring cam  35 , a crankshaft  40  is provided to protrude at a position deviating from a center of the covering portion  38 . To this crankshaft  40 , a cylindrical connecting piece  41  is rotatably attached via a not-illustrated needle bearing. In the ring cam  35 , a distance from a rotation center C 1  (approximately a position of the bolt  39  in the present embodiment) of the ring cam  35  to an outer circumferential surface on a side arranged further on a side of the crankshaft  40  than the rotation center C 1  is relatively short (thin), and a distance from the rotation center C 1  to the outer circumferential surface on a side arranged on an opposite side of the crankshaft  40  is relatively long (thick). Thus, the ring cam  35  functions as a cam that causes the balance weight  36  to be reciprocated (the detail thereof will be described below). The balance weight  36  is reciprocated approximately in an opposite phase to that of the crankshaft  40  and those of the plunger  34  and the blade  17 . 
     The balance weight  36  is made of a metal plate having predetermined weight as illustrated in  FIG. 3 or 6 . The balance weight  36  is approximately in a similar shape to that of the orbital cam  29   a . The balance weight  36  is provided with an opening portion penetrating in a direction along the rotation center and elongated in the horizontal direction, and in this opening portion, the ring cam  35  having the covering portion  38  is arranged. 
     The balance weight  36  is provided at an upper portion thereof with a rectangular projecting portion  36   a , and guide pins  42  are provided in the partition member  24  to regulate both side surfaces of this projecting portion  36   a . The balance weight  36  is also provided at a lower portion thereof with linear slits  43  extending in the up-down direction, and guide pins  44  engaging with the slits  43  are fixed in the partition member  24  to regulate the moving direction of the balance weight  36  in the up-down direction. 
     In the second cylindrical portion  14 , the plunger  34  is provided to enable reciprocating movement in the up-down direction and to be swingable in a front-back direction via a plunger holder  46 . The plunger holder  46  is in a cylindrical shape to enable an upper end portion of the plunger  34  to be slidably supported in the up-down direction, and the upper end portion is provided with a swing supporting-point portion  47 . Since the plunger  34  can be a vibration source, the upper end portion and the lower end portion of the plunger  34  are hollow-centered for weight saving to reduce vibration. 
     The plunger  34  is provided with a connector  48  slidably engaging with the connecting piece  41  and converting orbital movement of the connecting piece  41  into reciprocating movement of the plunger  34 . The connector  48  has an engaging groove  48   a  along the horizontal direction. The plunger holder  46 , the connecting piece  41 , and the connector  48  constitute a movement converting portion  49 . The connector  48  converts a movement force of the connecting piece  41  into a reciprocating movement force of the plunger  34 . 
     Also, the lower end of the plunger  34  is provided with a holding portion  50  holding the blade  17 , and a base of the blade  17  is held by this holding portion  50 . The base portion  12   a  is provided with an opening portion allowing movement of the blade  17  and the orbital mechanism  29 . The handle portion  15  is provided with a trigger  52 . A power supply cord  53  is extracted from a boundary part between the handle portion  15  and the first cylindrical portion  13 . The main body  12  is provided therein with a control portion  54 . The control portion  54  includes an electric circuit connecting the power supply cord  53  to the electric motor  16  and a switch provided in the electric circuit. The control portion  54  connects or disconnects the switch based on an operation of the trigger  52 . 
     Next, operations of the jigsaw  11  will be described while  FIG. 7 or 8  is referred to as needed.  FIG. 7  is a graph illustrating relationship between a ratio of inertia moment at planetary gear&#39;s input and output portions and torque acting on a normalized housing.  FIG. 8  is a graph illustrating relationship between a rotational speed ratio of an input shaft and an output shaft and the ratio of inertia moment at the planetary gear&#39;s input and output portions. 
     An operator connects the power supply cord  53  with an external power supply, thereafter holds the handle portion  15 , and thrusts the base portion  12   a  of the main body  12  on the surface  10   a  of the object  10  (refer to  FIG. 1 ). Subsequently, when the trigger  52  is activated, the switch of the control portion  54  is connected, power is supplied to the electric motor  16 , and the rotating shaft  16   a  is rotated in one direction. Torque of the rotating shaft  16   a  is transmitted from the driving gear  19  via the planetary gears  22  to the ring gear  27 . At this time, rotational speed of the ring gear  27  is lower than rotational speed of the electric motor  16 , and torque of the ring gear  27  is higher than torque of the electric motor  16 . That is, since the driving gear  19  and the planetary gears  22  constitute the decelerating mechanism, the rotational speed of the ring gear  27  is lower than rotational speed of the rotating shaft  16   a  when the torque of the electric motor  16  is transmitted to the plunger  34 . 
     When the driving gear  19  is rotated, the ring gear  27  is driven to be rotated via the planetary gears  22 . As a result, the ring gear  27  performs decelerated and high-torque rotating movement, and the ring cam  35 , the bolt  39 , the crankshaft  40 , and the connecting piece  41  are integrally rotated. When the ring gear  27  is rotated, the connecting piece  41  performs orbital movement around the rotation center C 1  in a plane perpendicular to the rotation center C 1 . A movement force of the crankshaft  40  is then transmitted via the connecting piece  41  to the connector  48 , and the connector  48  and the plunger  34  perform reciprocating movement in a direction along a center line D 1  or repeat rising and lowering. The blade  17  attached to the plunger  34  repeats rising and lowering to cause the object  10  to be cut by the blade  17 . In this manner, in the jigsaw  11 , the rotating movement of the rotating shaft  16   a  of the electric motor  16  is converted into the reciprocating movement of the plunger  34  and the blade  17 . Also, the balance weight  36  is guided by the guide pins  44  engaging with the slits  43  and performs reciprocating movement in the up-down direction approximately in an opposite phase to those of the plunger  34  and the blade  17 . Due to the reciprocating movement of the balance weight  36 , vibration in the up-down direction caused by the reciprocating movement of the plunger  34  and the blade  17  is reduced. 
     Further, the jigsaw  11  includes the orbital mechanism  29 . The orbital mechanism  29  swings the blade  17  in a predetermined angular range with the swing supporting-point portion  47  serving as a supporting point when the plunger  34  repeats rising and lowering. That is, the orbital mechanism  29  brings the blade  17  into contact with the object  10  in a procedure in which the plunger  34  rises and separates the blade  17  from the object  10  in a procedure in which the plunger  34  lowers. Accordingly, the object  10  can be cut efficiently. 
       FIGS. 7 and 8  describe effects of the present embodiment. In  FIG. 7 , “a ratio of inertia moment at planetary gear&#39;s input and output portions” (a horizontal axis of the graph) refers to a ratio of inertia moment at a rotated assembled part (a rotor of the electric motor  16 , the rotating shaft  16   a , and the like) arranged further on a side of the electric motor than the driving gear  19  to inertia moment at a rotated assembled part  55  arranged on a side of the ring gear  27  when the inertia moment at the rotated assembled part arranged further on the side of the electric motor than the driving gear  19  is 1. Also, “torque acting on a normalized housing” (a vertical axis of the graph) refers to torque acting on a housing when torque at the driving gear  19  input from the electric motor  16  is 1. As illustrated in  FIG. 7 , when the ratio of inertia moment at the planetary gear&#39;s input and output portions (the horizontal axis) is low, torque caused by a reaction force from the rotated assembled part arranged on the side of the electric motor acts on the housing in an opposite direction of the rotating direction of the electric motor  16 . When the ratio of inertia moment at the planetary gear&#39;s input and output portions (the horizontal axis) increases, the torque acting on the normalized housing (the vertical axis) increases. The rate of this increase is larger as a rotational speed ratio decreases more. When the torque acting on the housing is 0, the torque generated by the rotated assembled part arranged on the side of the electric motor and the torque generated by the rotated assembled part  55  arranged on the side of the ring gear  27  are equal to each other. At this time, a rotational reaction force is the smallest. The ratio of inertia moment is determined by shapes and materials of the respective members. For example, in a case in which the ratio of inertia moment at the planetary gear&#39;s input and output portions is set to be high, the electric motor  16  can be a brushless motor or a small-diameter motor (for example, the length of the rotor in the axial direction is set to be twice or more as long as the diameter), or at least a part of the ring gear  27  and the ring cam  35  can be made of a metal having a greater specific gravity than that of the rotor or can be provided with thickness (a weight portion) not contributing to power transmission. 
     In  FIG. 8 , “a rotational speed ratio (input shaft rotational speed/output shaft rotational speed)” (a horizontal axis of the graph) refers to a ratio of rotational speed of the rotating shaft  16   a  of the electric motor  16  to rotational speed of the ring gear  27 . A vertical axis has a similar meaning to that of the horizontal axis in  FIG. 7 .  FIG. 8  illustrates relationship between the rotational speed ratio (x) and the ratio of inertia moment at the planetary gear&#39;s input and output portions (y) in a case in which the torque acting on the housing is 0. That is, by setting x and y to satisfy the following equation, the torque acting on the housing can be minimum. 
         y= 0.92 x− 0.01 
     The most preferable examples of the motor rotational speed, the rotational speed of the ring gear, and the rotational speed ratio are as follows. 
     Motor rotational speed: 2800 rpm 
     Rotational speed of ring gear: 249 rpm
 
Rotational speed ratio: 11.25
 
By reducing the torque acting on the housing to about half, the operator can feel torque reduction at the time of activating the electric motor  16 . This range is approximately a range of (0.46x≦y≦1.38x). It is preferable to reduce the torque acting on the housing to about 20%. By doing so, the operator can feel significant torque reduction. To this end, the range can preferably be a range of (0.73x≦y≦1.11x) and can more preferably be a range of (0.82x≦y≦1.01x).
 
     As described above, with the jigsaw  11  according to the present embodiment, reduction in vibration can be achieved. That is, the blade  17  serving as a tip end tool included in the jigsaw  11  is driven to be reciprocated via the driving gear  19 , the planetary gears  22 , the ring gear  27 , and the movement converting portion  49  by the power of the electric motor  16  serving as a power source. At this time, the ring gear  27  is rotated around the rotation center by the power of the electric motor  16 . The jigsaw  11  is also provided with the balance weight  36  restricting vibration generated by the reciprocating movement. Accordingly, in comparison with a conventional jigsaw having a spur gear, the centroid of the main body  12  is located at a low position, a distance between the blade  17  and the centroid is shortened, and moment acting on the centroid decreases. Also, vibration can be restricted or reduced. 
     Also, since the rotating shaft  16   a  of the electric motor  16  and the center of the ring gear  27  are coaxial, and the rotating shaft  16   a  and the ring gear  27  are rotated in opposite directions, yawing of the main body  12  can be restricted or prevented. Further, since the support shafts  23  of the planetary gears  22  are arranged on the upper and lower sides of the driving gear  19  with the driving gear  19  interposed therebetween and are fixed to the main body  12 , balance can be maintained more easily than in a case in which the planetary gears  22  are arranged on the right and left sides of the driving gear  19  with the driving gear  19  interposed therebetween, and yawing of the main body  12  can be restricted effectively. 
     In this case, when the ratio of inertia moment at the assembled part  55  rotated in an equal direction to that of the ring gear  27  to inertia moment at the driving gear  19  is y, and the rotational speed ratio of the respective parts is x, y=0.92x−0.01 is established in the relationship between y and x. Accordingly, the torque acting on the housing, which is the main body  12 , can be minimum, and yawing and vibration of the main body  12  can be restricted effectively. Further, since the orbital mechanism  29  adapted to swing the blade  17  in the front-back direction is provided at the outer circumference of the ring gear  27 , the object  10  can be cut efficiently, and the operation efficiency can be improved. Meanwhile, the assembled part  55  rotated in an equal direction to that of the ring gear  27  refers to the ring gear  27 , the ring cam  35 , the bolt  39 , the crankshaft  40 , and the connecting piece  41 . 
     The reciprocating tool according to the embodiment of the present invention has been described above. However, the reciprocating tool according to the present invention is not limited to the aforementioned embodiment and can be altered in various ways within the scope described in the patent claims. For example, the reciprocating tool is not limited to the jigsaw and includes a cutting tool, an electric drill, a screw tightening machine, and the like. The reciprocating tool also includes a reciprocating tool in which power of a commercial power supply is supplied to an electric motor via a power supply cord and a reciprocating tool in which power of a battery pack attached to a main body is supplied to an electric motor. The battery pack houses battery cells and is detachable from the main body. 
     The reciprocating tool according to the present invention includes a tool provided in a power transmission path thereof from a power source to a rotating member with a gear transmission device, a belt transmission device, and a friction transmission device. Also, the power source generating power to be transmitted to the tip end tool includes an electric motor, an engine, and a hydraulic motor. Also, the present invention includes a reciprocating tool transmitting power of a power source to a tip end tool, such as a hammer, a hammer driver, a hammer drill, a saber saw, and a hedge trimmer. 
     REFERENCE SIGNS LIST 
     
         
           10  Object 
           10   a  Surface of object 
           11  Jigsaw (reciprocating tool) 
           12  Main body 
           12   a  Base portion 
           13  First cylindrical portion 
           14  Second cylindrical portion 
           14   a  Opening portion 
           14   b  Cover 
           15  Handle portion 
           16  Electric motor (power source) 
           16   a  Rotating shaft 
           17  Blade (tip end tool) 
           18  Fan 
           19  Driving gear 
           20  First bearing 
           20 A Second bearing 
           21  Gear holder 
           22  Planetary gear 
           23  Support shaft 
           24  Partition member 
           25  Opening portion 
           26  Internal tooth portion 
           27  Ring gear 
           28  Needle bearing 
           29  Orbital mechanism 
           29   a  Orbital cam 
           30  Eccentric cam portion 
           31  Opening portion 
           32  Guide pin 
           33  Guide groove 
           34  Plunger 
           35  Ring cam 
           36  Balance weight 
           37  Opening portion 
           38  Covering portion 
           39  Bolt 
           40  Crankshaft 
           41  Connecting piece 
           42  Guide pin 
           43  Slit 
           44  Guide pin 
           46  Plunger holder 
           47  Swing supporting-point portion 
           48  Connector 
           49  Movement converting portion 
           50  Holding portion 
           52  Trigger 
           53  Power supply cord 
           54  Control portion 
           55  Assembled part 
         C 1  Rotation center