Patent Publication Number: US-2023139412-A1

Title: Mixer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Japanese Patent Application No. 2021-178051, filed on Oct. 29, 2021, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a mixer for mixing fluid materials, such as paint and mortar, and non-fluid materials, such as sand and gravel. 
     2. Description of the Background 
     A mixer has a spindle protruding from a body accommodating a motor, and a mixer shaft connectable to the spindle to receive rotation of the motor. A blade is attached to the mixer shaft. The mixer can mix a material such as paint with the blade rotating together with the mixer shaft. A handle is fixed to the body. An operator holds left and right grips on the handle to support the body (e.g., German Utility Application Publication No. 202010014783). 
     BRIEF SUMMARY 
     The known mixer can have vibration in the body as the motor rotates and vibration at the mixing blade. Such vibration is transmitted to the hands of the operator holding the grips, thus lowering the operability. 
     One or more aspects of the present disclosure are directed to a mixer that is less likely to cause lower operability due to vibration. 
     A first aspect of the present disclosure provides a mixer, including: 
     a body including a motor and an output shaft to output rotation of the motor; 
     a mixer shaft connectable to the output shaft; 
     a handle attached to the body, the handle including a grip; and 
     a vibration isolator between the mixer shaft and the grip. 
     The mixer according to the above aspect of the present disclosure is less likely to cause lower operability due to vibration. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is an overall perspective view of a mixer according to a first embodiment. 
         FIG.  2    is a perspective view of a body of the mixer according to the first embodiment. 
         FIG.  3    is a plan view of the body of the mixer according to the first embodiment. 
         FIG.  4    is a side view of the body of the mixer according to the first embodiment. 
         FIG.  5    is a cross-sectional view taken along line A-A in  FIG.  3   . 
         FIG.  6    is an exploded perspective view of a vibration isolator in the first embodiment. 
         FIG.  7    is an enlarged cross-sectional view taken along line B-B in  FIG.  3   . 
         FIG.  8    is a perspective view of a body of a mixer according to a second embodiment. 
         FIG.  9    is an exploded perspective view of a vibration isolator in the second embodiment. 
         FIG.  10    is an enlarged longitudinal sectional view of a middle part of the vibration isolator in the second embodiment. 
         FIG.  11    is a perspective view of a mixer according to a third embodiment. 
         FIG.  12    is an exploded perspective view of a vibration isolator in the third embodiment. 
         FIG.  13    is an enlarged longitudinal sectional view of a middle part of the vibration isolator in the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
     Embodiments of the present disclosure will now be described with reference to the drawings. 
       FIG.  1    is an overall perspective view of a rechargeable mixer  1  as an example of a mixer.  FIG.  2    is a perspective view of a body.  FIG.  3    is a plan view of the body.  FIG.  4    is a side view of the body.  FIG.  5    is a cross-sectional view taken along line A-A in  FIG.  3   . 
     The mixer  1  includes a body  2  and a mixer shaft  3 . 
     The body  2  includes, as its housing, a motor housing  4  and a reducer housing  5 . The motor housing  4  accommodates a motor  6  in its rear portion and a controller  8  in its front portion. The motor  6  is supported with a rotational shaft  7  extending downward. The rotational shaft  7  has its lower end protruding in the reducer housing  5 . 
     The motor housing  4  has a battery mount  9  on its upper portion. The battery mount  9  includes a terminal base  10 . A battery pack  11  is slid on and attached to the terminal base  10  from the front. A battery cover  12  is attached to the upper portion of the motor housing  4 . The battery cover  12  covers the battery pack  11  and the battery mount  9  from above. 
     The reducer housing  5  accommodates a reducer  15 . The reducer  15  includes a spindle  16 . The spindle  16  protrudes downward from the lower end of the reducer housing  5 . The spindle  16  has a thread  17  on its lower end. The reducer  15  includes multiple gears. The reducer  15  reduces rotation of the rotational shaft  7  and transmits the reduced rotation to the spindle  16 . A switch lever  18  is located on a right side surface of the reducer housing  5 . The rotational speed of the spindle  16  is switchable between two levels, or specifically, high and low, in response to an operation on the switch lever  18 . 
     The mixer shaft  3  is coaxially connectable with the thread  17  on the spindle  16 . A blade  19  is attached to a lower end of the mixer shaft  3 . 
     A handle  20  is attached to the body  2 . The handle  20  includes a fixture  21 , a pair of left and right front arms  22 , a pair of left and right rear arms  23 , a left grip  24 , and a right grip  25 . 
     The fixture  21  is attached to the motor housing  4 . The fixture  21  is U-shaped as viewed in plan and is a vertically thin metal sheet. The motor housing  4  has, on its outer peripheral surface, a flange  26  supporting the fixture  21  from below. The fixture  21  on the upper surface of the flange  26  is fastened to the flange  26  with multiple bolts  27  from above. 
     The front arms  22  are integral with the fixture  21  and extend from the front end of the fixture  21  outward to the left and to the right. The rear arms  23  are integral with the fixture  21  and extend from the rear portion of the fixture  21  outward to the left and to the right. Each of the front arms  22  and the rear arms  23  has its outer left and right ends receiving a protective portion  28  formed from rubber. The protective portions  28  are thicker than the arms  22  and  23 . 
     The left grip  24  and the right grip  25  are located nearer the middle in the lateral direction than the protective portions  28 . The left grip  24  and the right grip  25  extend across the ends of the front arms  22  and the rear arms  23  in the front-rear direction. The left grip  24  and the right grip  25  have their front ends fastened to the ends of the front arms  22  with screws  29  and their rear ends fastened to the ends of the rear arms  23  with screws  29 . 
     Each of the left grip  24  and the right grip  25  is dividable into two halves, or specifically, an upper half part  30  and a lower half part  31 , with the corresponding one of the front and rear arms  22  and  23 . The upper half part  30  and the lower half part  31  are joined together with multiple screws  32  from above. 
     As shown in  FIG.  6   , the right grip  25  accommodates a switch  33 . The switch  33  includes a trigger  34 . The trigger  34  protrudes from a lower surface of the right grip  25 . A lock button  35  is located on a left side surface of the right grip  25 . The lock button  35  locks the trigger  34  being pressed. A lock lever  36  is located in front of the switch  33 . The lock lever  36  can slide between a position at which the trigger  34  is locked and cannot be pressed and a position at which the trigger  34  is allowed to be pressed. 
     The lock lever  36  includes an adjustment dial  37  on its front portion. The rotational speed of the motor  6  can be adjusted by rotating the adjustment dial  37 . The adjustment dial  37  is exposed on an upper surface of the right grip  25 . 
     A lead wire cover  38  is fastened to the upper surfaces of the right rear arm  23  and the fixture  21  with screws. A lead wire connected to the switch  33  accommodated in the right grip  25  and a lead wire connected to a substrate for the adjustment dial  37  are routed inside the lead wire cover  38 . Each of these lead wires is routed into the motor housing  4  through a wiring port (not shown) in the rear surface of the motor housing  4 . The lead wire for the switch  33  is connected to the controller  8  and to the terminal base  10 . The lead wire for the adjustment dial  37  is routed to the controller  8 . 
     Vibration isolators  40  are located between the front and rear arms  22  and  23  and the front and rear ends of the left and right grips  24  and  25 . The structure of each vibration isolator  40  will now be described. Each vibration isolator  40  has the same structure. The vibration isolator  40  between the front arm  22  on the right and the front end of the right grip  25  shown in  FIG.  6    will now be described as a typical example. 
     At the front end of the right grip  25 , the upper half part  30  has an insertion hole  41  extending in the vertical direction. A screw  29  is placed in the insertion hole  41  from above. The lower half part  31  has a screw boss  42  extending upward to receive the screw  29  being screwed. The front arm  22  has a through-hole  43 , through which the screw boss  42  extends. The lower half part  31  includes a positioner  44  at the rear outside of the screw boss  42 . The positioner  44  is cylindrical and extends upward. The front arm  22  has, in its rear edge, a cutout  45  to be engaged with the positioner  44 . 
     Each vibration isolator  40  includes a rubber member  46  integral with the protective portion  28 . The rubber member  46  is thinner than the protective portion  28  and extends from the protective portion  28  toward the middle along the front arm  22 . The protective portion  28  and the rubber member  46  have a slit  47  to receive the end of the front arm  22  as also shown in  FIG.  7   . The slit  47  divides the rubber member  46  into a pair of divided pieces  48  above and below the front arm  22 . An upper divided piece  48  has, on its upper surface, two engagement projections  49  that engage with the inside of the upper half part  30 . A lower divided piece  48  has, on its lower surface, two engagement projections  49  that engage with the inside of the lower half part  31 . 
     The divided pieces  48  each include a circular portion  50  integral with their ends to cover the through-hole  43  from above or from below. Each circular portion  50  has a greater diameter than the through-hole  43 . The circular portions  50  have, on their facing surfaces, protrusions  51  that are circular as viewed in plan. The protrusions  51  fit into the through-hole  43  from above and from below. A space S is left in the vertical direction between the protrusions  51  in the through-hole  43 . Each circular portion  50  has a through-hole  52  at its center. The screw boss  42  extends through each through-hole  52  from below. 
     To attach the right grip  25  to the front arm  22 , the end of the front arm  22  is first placed into the slit  47  in the protective portion  28  and the rubber member  46 . The protrusions  51  on the upper and lower divided pieces  48  then fit into the through-hole  43  in the front arm  22  from above and from below. This positions the protective portion  28  and the rubber member  46 . 
     The screw boss  42  in the lower half part  31  is then placed through the through-hole  52  in each circular portion  50 , and the positioner  44  is engaged with the cutout  45 . The screw boss  42  then extends through each circular portion  50  and protrudes above the rubber member  46 . In this state, the upper half part  30  is placed over the lower half part  31  from above. The screw  29  extending through the insertion hole  41  is then screwed into the screw boss  42 . As shown in  FIG.  7   , the upper half part  30  and the lower half part  31  including the screw joint are joined to the front arm  22  with the rubber member  46  in between. In this state, the right grip  25 , including the screw boss  42  and the screw  29 , is not in direct contact with the front arm  22 . 
     An operator of the mixer  1  holds the left grip  24  and the right grip  25  on the handle  20 . The mixer  1  is thus supported with the mixer shaft  3  protruding downward. The operator in this posture presses the trigger  34  on the right grip  25  to turn on the switch  33 . The motor  6  is then driven to rotate the rotational shaft  7 . The rotation of the rotational shaft  7  is reduced by the reducer  15  in either a high speed mode or a variable speed mode selected with the switch lever  18  and is transmitted to the spindle  16 . As the mixer shaft  3  connectable to the spindle  16  rotates, the blade  19  that rotates with the mixer shaft  3  mixes a material such as paint. 
     During the operation, the operator holding the left and right grips  24  and  25  to support the mixer  1  views, from above the motor housing  4  and the battery cover  12 , the blade  19  on the lower end of the mixer shaft  3 , the mixer shaft  3 , and the material being mixed. In this state, the fixture  21  in the handle  20  is not in front of the motor housing  4  and the battery cover  12  and thus can avoid obstructing the field of view of the operator. The operator can thus reliably view, for example, the blade  19 . 
     During the operation, vibration is generated on the blade  19  or vibration is generated as the motor  6  is driven. Such vibration is transmitted from the body  2  to the front and rear arms  22  and  23  of the handle  20 . The rubber members  46  in the vibration isolators  40  are between the front and rear arms  22  and  23  and the left and right grips  24  and  25 . Thus, the rubber member  46  reduces the vibration. The vibration in the vertical direction is absorbed by elastic deformation of the circular portion  50  of each divided piece  48  in the thickness direction above and below the front and rear arms  22  and  23 . The vibration in the front-rear and lateral directions is absorbed by elastic deformation of the protrusions  51  that fit in the through-hole  43 . The space S is left in the thickness direction between the protrusions  51 . This structure allows vibration isolation without the protrusions  51  being in contact with each other and obstructing elastic deformation. 
     This structure reduces vibration transmitted to the hands holding the left and right grips  24  and  25 , thus reducing discomfort felt by the operator. 
     The mixer  1  according to the first embodiment includes the body  2  including the motor  6  and the spindle  16  (output shaft) to output the rotation of the motor  6 . The mixer  1  includes the mixer shaft  3  connectable to the spindle  16  and the handle  20  attached to the body  2  and including the left and right grips  24  and  25  (grip). The mixer  1  includes the vibration isolators  40  between the mixer shaft  3  and the left and right grips  24  and  25  (between the front and rear arms  22  and  23  and the left and right grip  24  and  25  in the present embodiment). 
     In this structure, vibration generated in the body  2  as the motor  6  rotates and vibration generated on the mixing blade  19  are absorbed by the vibration isolators  40 . Thus, vibration is less likely to be transmitted directly to the hands of the operator holding the left and right grips  24  and  25 . This structure thus is less likely to cause lower operability due to vibration. 
     The handle  20  includes the fixture  21  attached to the body  2 , the front and rear arms  22  and  23  (arm) protruding from the fixture  21 , and the left and right grips  24  and  25  (grip) attached to the front and rear arms  22  and  23 . The vibration isolators  40  are between the front and rear arms  22  and  23  and the left and right grips  24  and  25 . 
     This structure effectively reduces vibration transmitted from the left and right grips  24  and  25  to the hands of the operator. 
     The vibration isolators  40  include the rubber members  46  (elastic member) between the front and rear arms  22  and  23  and the left and right grips  24  and  25 . 
     Each vibration isolator  40  is thus formed easily. 
     Each of the left and right grips  24  and  25  is dividable into two halves, or specifically, the upper half part  30  and the lower half part  31  (half parts), with the corresponding one of the front and rear arms  22  and  23  in between. The rubber member  46  covers the front or rear arm  22  or  23  and is held between the two parts, or specifically, between the upper half part  30  and the lower half part  31 . 
     The rubber member  46  is readily placed between the upper half part  30  and the lower half part  31  when the upper half part  30  and the lower half part  31  are joined together. 
     The upper half part  30  and the lower half part  31  are joined with a screw  29  (screw member) extending through the through-hole  43  in the front or rear arm  22  or  23 . The lower half part  31  (one half part) includes the screw boss  42  extending through the through-hole  43 . Each rubber member  46  includes the protrusion  51  extending through the screw boss  42  and fitting in the through-hole  43 . 
     This structure reliably allows vibration isolation at the screw joint between the upper half part  30  and the lower half part  31 . 
     The front and rear arms  22  and  23  are plates. Each rubber member  46  has the slit  47  receiving the front or rear arm  22  or  23 . The slit  47  divides the rubber member  46  into the two divided pieces  48  in the thickness direction of the front or rear arm  22  or  23 . Each divided piece  48  includes the protrusion  51 . 
     This allows vibration isolation at the screw joint and also facilitates positioning of the rubber member  46  on the front or rear arm  22  or  23 . 
     The space S is left in the thickness direction between the protrusions  51  on the divided pieces  48  in the through-hole  43 . 
     This structure allows vibration isolation without the protrusions  51  being in contact with each other and obstructing elastic deformation of the divided pieces  48 . 
     The front and rear arms  22  and  23  are laterally symmetric with respect to the body  2 . The left and right grips  24  and  25  are located on the respective left and right front and rear arms  22  and  23 . 
     This structure supports the body  2  in a balanced manner, and reduces vibration in both the left and right grips  24  and  25 . 
     The front and rear arms  22  and  23  protrude outward from the left grip  24  and each include the protective portion  28  connecting to the rubber member  46  at the protruding end of the corresponding arm, and the front and rear arms  22  and  23  protrude outward from the right grip  25  and each include the protective portion  28  connecting to the rubber member  46  at the protruding end of the corresponding arm. 
     Thus, the ends of the front and rear arms  22  and  23  are protected. The protective portions  28  are attached when the rubber members  46  are attached. 
     In the first embodiment, the shape of each vibration isolator may be changed as appropriate. For example, each vibration isolator is not limited to the rubber member including two divided pieces divided by the slit, but may be a structure including two rubber members that are separate from each other above and below the arm. The rubber member may include upper and lower divided pieces continuous with each other in the through-hole. The screw boss may extend through the continuous pieces in the through-hole. 
     The rubber member may be separate from the protective portion. 
     The screw boss may be in the upper half part, instead of being in the lower half part. 
     The upper half part and the lower half part may be screwed at multiple positions with the front and rear arms. In this case, the vibration isolator may be provided for each screw joint, or may be formed across multiple screw joints. 
     The handle includes the front and rear arms on each of the left and the right. The handle may include the front arm alone on each of the left and the right, and may have the left and right grips attached to each front arm. 
     Second Embodiment 
     A second embodiment will now be described. The main components of a mixer according to the present embodiment are the same as in the first embodiment. The same components as in the first embodiment are given the same reference numerals and will not be described repeatedly. The mixer according to the present embodiment will be described focusing on its vibration isolators. 
     A mixer  1 A shown in  FIG.  8    includes vibration isolators  40 A between the body  2  and the handle  20  at positions at which the fixture  21  is fixed with the bolts  27 . 
     The fixture  21  has fastener holes  55  each with a greater diameter than the bolt  27  as shown in  FIGS.  9  and  10   . A sleeve  56  is externally located on the bolt  27  and extends through the fastener hole  55 . The sleeve  56  has a smaller diameter than the fastener hole  55 . 
     A pair of rubber members  57  that are circular as viewed in plan are located above and below the fixture  21  to serve as a vibration isolator  40 A. The rubber members  57  each have a greater diameter than the fastener hole  55 . The rubber members  57  each have a protrusion  58  on their facing surfaces. The protrusion  58  fits into the fastener hole  55 . A space S is left in the thickness direction between the facing protrusions  58 . Each rubber member  57  has a through-hole  59  at its center. The bolt  27  and the sleeve  56  extend through the through-hole  59 . 
     The axial length of the sleeve  56  is substantially equal to the vertical thickness of the portion including the rubber members  57  above and below the fixture  21 . Washers  60  are located to sandwich the sleeve  56  and the upper and lower rubber members  57 . The bolt  27  extends through the washers  60 . 
     When attaching the handle  20  to the mixer  1 A, the sleeve  56  is placed in the fastener hole  55  and the rubber members  57  are placed above and below the fastener hole  55 . With the washers  60  above and below the rubber members  57 , the fixture  21  is placed on the flange  26 . In this state, the bolt  27  is placed, from above, through the washers  60  and the sleeve  56  into a threaded hole  61  in the flange  26 . A nut  62  is held in a lower portion of the threaded hole  61 . As the bolt  27  is tightened with the nut  62 , the washers  60  and the sleeve  56  are fixed to the flange  26  with the bolt  27 . In this state, the fixture  21  is held between the upper and lower rubber members  57  between the washers  60  and is not in contact with the sleeve  56  and the washers  60 . 
     Thus, any vibration generated during operation transmitted to the motor housing  4  is reduced by the rubber members  57  with the vibration isolators  40 A between the motor housing  4  and the fixture  21 . The vibration in the vertical direction is absorbed by elastic deformation of the rubber members  57  above and below the fixture  21 . The vibration in the front-rear and lateral directions is absorbed by elastic deformation of the protrusions  58  that fit in the fastener hole  55 . 
     This structure reduces vibration transmitted to the hands holding the left and right grips  24  and  25 , thus reducing discomfort felt by the operator. 
     The mixer  1 A according to the second embodiment includes the body  2  including the motor  6  and the spindle  16  to output the rotation of the motor  6 . The mixer  1 A includes the mixer shaft  3  connectable to the spindle  16  and the handle  20  attached to the body  2  and including the left and right grips  24  and  25 . The mixer  1 A includes the vibration isolators  40 A between the mixer shaft  3  and the left and right grips  24  and  25  (between the body  2  and the handle  20 ). 
     In this structure, vibration generated in the body  2  as the motor  6  rotates and vibration generated on the mixing blade  19  are absorbed by the vibration isolators  40 A and are less likely to be transmitted directly to the hands of the operator holding the left and right grips  24  and  25 . This structure thus is less likely to cause lower operability due to vibration. 
     The vibration isolators  40 A are located between the body  2  and the handle  20 . 
     This structure effectively reduces vibration transmitted from the body  2  to the handle  20 . 
     The handle  20  includes the fixture  21  attached to the body  2 , the front and rear arms  22  and  23  attached to the fixture  21 , and left and right grips  24  and  25  attached to the front and rear arms  22  and  23 . Each vibration isolator  40 A includes the rubber members  57  between the body  2  and the fixture  21 . 
     Each vibration isolator  40 A is thus formed easily. 
     The fixture  21  is joined with the bolts  27  (screw member) extending through the fastener holes  55  in the fixture  21 . The rubber members  57  are also between the fixture  21  and the bolts  27 . 
     This allows effective vibration isolation at the fastening portions with the bolts  27 . 
     The sleeve  56  extending through the fastener hole  55  is externally located on each bolt  27 . Each rubber member  57  includes the protrusion  58  that fits in the fastener hole  55  and surrounds the sleeve  56 . 
     This structure allows reliable vibration isolation at the fastener holes  55 . 
     In the second embodiment, the number of bolts is not limited. More bolts or fewer blots than in the embodiment may be used as appropriate. 
     Although the rubber members are separately provided above and below the fixture in the second embodiment, the rubber members may be continuous with each other and fit in the fastener hole through which the bolt and the sleeve extend. 
     Rubber members continuous with and integral with one another may be used across adjacent multiple bolts. 
     The fixture may have a shape different from the shape in the above embodiments. The fixture may be annular around the body. 
     The flange for fastening the fixture may have a shape different from the shape continuous in the circumferential direction of the body. The flange may protrude intermittently from the body at the fastening portions with the bolts. 
     Third Embodiment 
     A mixer  1 B shown in  FIG.  11    includes a vibration isolator  40 B between the spindle  16  and the mixer shaft  3  as shown in  FIGS.  12  and  13   . An upper sleeve  65  is screwed and coupled to the thread  17  on the spindle  16 . The upper sleeve  65  has a flange  66  on its upper end. The upper sleeve  65  has, on its lower periphery, an inner spline  67  with multiple spline teeth extending in the axial direction. An outer sleeve  68  is externally located on the upper sleeve  65 . The outer sleeve  68  has its upper end fixed to the flange  66  on the upper sleeve  65 . The outer sleeve  68  has an outer stopper  69  on its inner circumference at the bottom. The outer stopper  69  is annular and protrudes inward in the radial direction. 
     A lower sleeve  70  is externally located on the upper sleeve  65 . The lower sleeve  70  has a diameter smaller than the inner diameter of the outer sleeve  68 . The lower sleeve  70  has, on its inner circumference, an outer spline  71  with multiple spline teeth extending in the axial direction. The outer spline  71  is engaged with the inner spline  67  on the upper sleeve  65 . Thus, the lower sleeve  70  can rotate integrally with the upper sleeve  65  and move relative to the upper sleeve  65  in the vertical direction. The lower sleeve  70  has its upper portion between the upper sleeve  65  and the outer sleeve  68 . The lower sleeve  70  includes an annular inner stopper  72  on its outer circumference at the upper edge. The inner stopper  72  protrudes radially outward. The inner stopper  72  is engageable, from above, with the outer stopper  69  in the outer sleeve  68 . 
     A coil spring  73  is externally located on the upper sleeve  65  between the flange  66  and the lower sleeve  70  to form the vibration isolator  40 B. Thus, the lower sleeve  70  is urged by the coil spring  73  to a lower limit position at which the inner stopper  72  is engaged with the outer stopper  69  from above. 
     A coupler  74  is fixed to the lower end of the lower sleeve  70 . The upper end of the mixer shaft  3  is inserted and fixed at the center of the coupler  74 . The coupler  74  is locked from rotation with a tightening nut  75 . 
     When the spindle  16  in the mixer  1 B rotates, the outer sleeve  68  and the lower sleeve  70 , which are integral with the upper sleeve  65  in the direction of rotation, rotate together. As the lower sleeve  70  rotates, the mixer shaft  3  rotates together with the coupler  74 . 
     When the mixer shaft  3  moves up and down under vibration on the blade  19  during operation, the lower sleeve  70 , which is integral with the mixer shaft  3 , moves up and down along the outer circumference of the upper sleeve  65 , thus causing the coil spring  73  to expand and contract in the axial direction. The vibration is reduced by the coil spring  73 . 
     This structure reduces vibration transmitted to the hands holding the left and right grips  24  and  25 , thus reducing discomfort felt by the operator. 
     The mixer  1 B according to the third embodiment includes the body  2  including the motor  6  and the spindle  16  to output the rotation of the motor  6 . The mixer  1 B includes the mixer shaft  3  connectable to the spindle  16  and the handle  20  attached to the body  2  and including the left and right grips  24  and  25 . The mixer  1 B includes the vibration isolator  40 B between the mixer shaft  3  and the left and right grips  24  and  25  (between the spindle  16  and the mixer shaft  3 ). 
     In this structure, vibration generated on the mixing blade  19  is absorbed by the vibration isolator  40 B and is less likely to be transmitted directly to the hands of the operator holding the left and right grips  24  and  25 . This structure thus is less likely to cause lower operability due to vibration. 
     The vibration isolator  40 B is located between the spindle  16  and the mixer shaft  3 . This structure effectively reduces vibration transmitted from the mixer shaft  3  to the body  2 . 
     The mixer shaft  3  is connectable to the spindle  16  to be integrally rotatable and axially movable relative to the spindle  16 . The vibration isolator  40 B is the coil spring  73  that urges the mixer shaft  3  in a direction to be separate from the spindle  16 . 
     This structure effectively reduces the vibration of the mixer shaft  3  in the axial direction. 
     The upper sleeve  65  (first sleeve) is integrally attached to the spindle  16 . The lower sleeve  70  (second sleeve) spline-connected to the upper sleeve  65  is integrally attached to the mixer shaft  3 . The coil spring  73  is between the upper sleeve  65  and the lower sleeve  70 . 
     The coil spring  73  is at a position that can effectively reduce vibration. 
     The upper sleeve  65  includes the outer sleeve  68  (stopper member) to be engaged with the lower sleeve  70  to regulate a position to which the mixer shaft  3  protrudes in the direction to be separate from the spindle  16 . 
     This structure can reliably regulate the range of movement of the mixer shaft  3  relative to the spindle  16 . 
     In the third embodiment, multiple coil springs may be used. For example, two coil springs with different diameters, or a coil spring with a greater diameter and a coil spring with a smaller diameter, may be used. 
     The vibration isolator is not limited to such a coil spring. The vibration isolator may be a disc spring or a rubber member. 
     Although the lower sleeve is externally located on the upper sleeve and spline-connected to the upper sleeve in the above embodiment, the upper sleeve may be externally located on the lower sleeve and spline-connected to the lower sleeve. 
     The outer sleeve may be arranged on the lower sleeve. 
     In each of the above embodiments, the grips are not limited to the grips each including the upper and lower half parts. The grips may each include left and right half parts or three or more parts. Each grip may be an integral cylinder, without being dividable. Such grips have increased strength. 
     The shape of the body, the arrangement of the motor accommodated in the body, and the arrangement of the controller may be changed as appropriate. 
     The battery mount may not be in the upper portion of the motor housing. The battery mount may be located on a side surface or a rear surface of the motor housing. 
     The power supply may not be a battery. The present disclosure is also applicable to a structure in which power is supplied to the motor via a power cord from utility power (alternating current or AC power supply). 
     The length of the mixer shaft, the attaching structure for the mixer shaft attached to the spindle, as well as the shape of the blade are not limited to those described in the above embodiments. 
     Any combination of the vibration isolators in the above embodiments may be included in the mixer. For example, the vibration isolators described in the first to third embodiments may be all included in a single mixer, or any two of the vibration isolators described in the first to third embodiments may be included in a single mixer. 
     REFERENCE SIGNS LIST 
     
         
           1  mixer 
           2  body 
           3  mixer shaft 
           4  motor housing 
           5  reducer housing 
           6  motor 
           7  rotational shaft 
           8  controller 
           15  reducer 
           16  spindle 
           19  blade 
         handle 
           21  fixture 
           22  front arm 
           23  rear arm 
           24  left grip 
         right grip 
           26  flange 
           28  rubber 
           29 ,  32  screw 
           30  upper half part 
           31  lower half part 
           40  vibration isolator 
           41  insertion hole 
           42  screw boss 
           46  rubber member 
           47  slit 
           48  divided piece 
           49  engagement projection 
           50  circular portion 
           51 ,  58  protrusion 
           55  fastener hole 
           56  sleeve 
           57  rubber member 
           60  washer 
           65  upper sleeve 
           66  flange 
           68  outer sleeve 
           69  outer stopper 
           70  lower sleeve 
           72  inner stopper 
           73  coil spring 
         S space