Abstract:
A vibrational frequency adjustment device comprises, as a vibrational frequency adjustment means ( 22 ): a first conversion means ( 40 ) which is provided with an input-side rotating member ( 41 ), an output-side rotating member ( 42 ), and a one-way clutch ( 44 ) for transmitting only the rotational motion in one direction of the input-side rotating member ( 41 ) to the output-side rotating member ( 42 ) and which, by causing the input-side rotating member ( 41 ) to pivot in a reciprocating manner by a set angle by means of the reciprocating linear motion of an output shaft ( 10 ), transmits only the forward motion or the reverse motion of the input-side rotating member ( 41 ) to the output-side rotating member ( 42 ) through the one-way clutch ( 44 ) to thereby rotate the output-side rotating member ( 42 ) by a given angle; and a second conversion means ( 50 ) which converts the rotational motion of the output-side rotating member ( 42 ) into the reciprocating linear motion of a second shaft member ( 43 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a vibrational frequency adjustment device for adjusting the vibrational frequency of reciprocating linear motion and a water flow type oral cavity cleaning device using the same. 
       BACKGROUND ART 
       [0002]    As an electric toothbrush with a cleaning head making a reciprocating linear motion, a motor-powered electric toothbrush including conversion means that converts rotation of a pinion fixedly attached to a rotation shaft of a motor into rotation of a face gear about an axial core orthogonal to the rotation shaft and then converts the rotation of the face gear into reciprocating linear motion of a drive shaft via a crank shaft, is widely employed because of its low-cost manufacturability. However, in the motor-powered electric toothbrush, the face gear is rotated at a reduced speed by engagement of gear wheels, and thus the cleaning head is set with a vibrational frequency of 1,500 to 5,000 cpm and an amplitude of 3 to 7 mm, whereby there is a limit for providing the cleaning head with a high vibrational frequency. Accordingly, so-called sonic electric toothbrushes having a cleaning head with a vibrational frequency of 5,000 to 11,000 cpm and an amplitude of 0.2 to 1.0 mm, have recently been suggested and put into practical use, in which a plurality of gears is combined (refer to Patent Document 1, for example), a scotch yoke mechanism is used (refer to Patent Document 2, for example), or a linear actuator having a permanent magnet and a coil is used (refer to Patent Document 3, for example). 
         [0003]    Meanwhile, as an oral cavity cleaning device, there is put into commercial use a water flow type oral cavity cleaning device including a pump capable of discharging a cleaning liquid by reciprocating linear motion of a piston; pump drive means driving the piston; and a discharge nozzle for the cleaning liquid, in which the cleaning liquid can be intermittently injected from the nozzle to thereby efficiently clean interdental gaps and periodontal pockets with the cleaning liquid (refer to Patent Document 4, for example). 
         [0004]    In addition, as a water flow type oral cavity cleaning device, there is suggested a water flow type oral cavity cleaning device in which a connection member capable of being connected to a drive shaft of a drive unit of a motor-powered electric toothbrush is provided so that a pump can be driven by the drive unit of the motor-powered electric toothbrush, whereby pump drive means of the water flow type oral cavity cleaning device can be used also as a drive unit of a motor-powered electric toothbrush (refer to Patent Document 5, for example). 
       CITATION LIST 
     Patent Literature 
       [0005]    Patent Document 1: WO 2004/112536 
         [0006]    Patent Document 2: JP-A No. 2007-215796 
         [0007]    Patent Document 3: JP-A No. 2002-176758 
         [0008]    Patent Document 4: JP-A No. 11-128252 
         [0009]    Patent Document 5: JP-A No. 5-161663 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0010]    The invention disclosed in Patent Document 5 allows a drive unit of a motor-powered electric toothbrush to be used also as the pump drive means of the water flow type oral cavity cleaning device, and therefore the water flow type oral cavity cleaning device can be utilized with reduction in economic burden on a user by using a drive unit of a currently used electric toothbrush as the pump drive means of the water flow type oral cavity cleaning device. However, when a drive unit of a sonic electric toothbrush, instead of a motor-powered electric toothbrush, is connected to the water flow type oral cavity cleaning device, it is not possible to provide a sufficient discharge amount of the cleaning liquid due to a short stroke of the drive shaft of 0.2 to 1.0 mm, for example, and it is not possible to allow a piston of the pump to make a reciprocating linear motion at a high vibrational frequency of 5,000 to 11,000 cpm, which makes the water flow type oral cavity cleaning device unpractical. In addition, it is obvious that sonic electric toothbrushes use piston-type pumps due to a short stroke of the drive shaft, and even using diaphragm pumps cannot provide a sufficient discharge amount of cleaning liquid. Accordingly, it is considered as being extremely difficult to use a drive unit of a sonic electric toothbrush also as a pump drive means of water flow type oral cavity cleaning device. 
         [0011]    Accordingly, an object of the present invention is to provide a vibrational frequency adjustment device that realizes easy adjustment of the vibrational frequency and amplitude of a reciprocating linear motion by a simple mechanical configuration, and a water flow type oral cavity cleaning device that uses the vibrational frequency adjustment device to thereby allow pump drive means to be used also as a drive unit of a sonic electric toothbrush. 
       Solution to Problem 
       [0012]    A vibrational frequency adjustment device of the present invention includes first conversion means that includes an input-side rotational member, an output-side rotational member, and a one-way clutch transferring only a rotational motion of the input-side rotational member in one direction to the output-side rotational member, and allows the input-side rotational member to make a reciprocating rotational motion by a set angle by a reciprocating linear motion of a first shaft member, thereby to transfer only a forward motion or a backward motion of the input-side rotational member to the output-side rotational member via the one-way clutch and rotate the output-side rotational member by each specific angle; and second conversion means that converts the rotational motion of the output-side rotational member into a reciprocating linear motion of a second shaft member. 
         [0013]    In the vibrational frequency adjustment device, when the first shaft member makes a reciprocating linear motion, the input-side rotational member of the first conversion means makes a reciprocating rotational motion by a set angle, only a forward motion or a backward motion of the input-side rotational member is transferred to the output-side rotational member via the one-way clutch, and then the output-side rotational member rotates by each specific angle. In addition, the second conversion means converts the rotation of the output-side rotational member into a reciprocating linear motion of the second shaft member, whereby the second shaft member makes one reciprocating linear motion each time the first shaft member makes a plurality of reciprocating linear motions and the output-side rotational member makes one rotation. For example, if the output-side rotational member rotates by 30 degrees by one reciprocating motion of the first shaft member, the second shaft member makes one reciprocating linear motion by 12 reciprocating linear motions of the first shaft member, which allows the vibrational frequency of the second shaft member to be adjusted to 1/12 of the vibrational frequency of the first shaft member. In this manner, in the vibrational frequency adjustment device, the vibrational frequency of the second shaft member can be adjusted inexpensively and reliably by employing a simple mechanical configuration having the one-way clutch as the first conversion means. In addition, the second conversion means uses a crank mechanism or a cam mechanism or the like to convert a rotational motion of the output-side rotational member into a reciprocating motion of the second shaft member, and the second conversion means also makes it possible to arbitrarily adjust the amplitude of the second shaft member. 
         [0014]    In a preferred embodiment, the first conversion means is provided with a lever member that converts a reciprocating linear motion of the first shaft member into a reciprocating rotational motion of the input-side rotational member. In this case, adjusting a lever length of the lever member makes it possible to adjust the angle of a reciprocating rotational motion of the input-side rotational member at a reciprocating linear motion of the first shaft member and adjust the ratio of the vibrational frequency of the first shaft member and the vibrational frequency of the second shaft member. 
         [0015]    The second conversion means may be configured in such a manner that a first gear is formed at an outer peripheral part of the output-side rotational member; a second gear engaging with the first gear is provided; and an eccentric cam allowing the second shaft member to make a reciprocating linear motion is arranged at the second gear. In this case, the number of reciprocating linear motions of the second shaft member at one rotation of the output-side rotational member can be altered by changing the ratio of number of teeth between the first gear and the second gear. In addition, the amplitude of the second shaft member can be regulated by adjusting an eccentric distance of the eccentric cam. 
         [0016]    A water flow type oral cavity cleaning device of the present invention includes: a pump capable of discharging a cleaning liquid by a reciprocating linear motion of a piston; pump drive means driving the piston; and a discharge nozzle for the cleaning liquid, in which the pump drive means includes the vibrational frequency adjustment device and a drive means main body having a first shaft member making a reciprocating linear motion, the input-side rotational member is allowed to make a reciprocating rotational motion by a set angle by a reciprocating linear motion of the first shaft member, thereby to transfer only a forward motion or a backward motion of the input-side rotational member to the output-side rotational member via the one-way clutch and rotate the output-side rotational member by each specific angle, and the rotational motion of the output-side rotational member is converted into a reciprocating linear motion of the second shaft member, thereby to allow the piston to make a reciprocating linear motion at the second shaft member. 
         [0017]    In the water flow type oral cavity cleaning device, a reciprocating linear motion of the first shaft member in the drive means main body is switched to a reciprocating linear motion of the second shaft member in the vibrational frequency adjustment device, whereby the piston of the pump can be driven by the second shaft member. In the vibrational frequency adjustment device, the vibrational frequency and amplitude of a reciprocating linear motion of the second shaft member can be arbitrarily adjusted as described above. Accordingly, it is possible to adjust a reciprocating linear motion of the first shaft member vibrating at a high speed to a low-speed reciprocating linear motion of the second shaft member, for example, and use a drive unit of a sonic electric toothbrush also as the drive means main body of the water flow type oral cavity cleaning device. 
         [0018]    In a preferred embodiment, the drive means main body is used also as a drive unit of a sonic electric toothbrush. In this configuration, the water flow type oral cavity cleaning device can be driven by the drive unit of the currently used sonic electric toothbrush, thereby to reduce an economic burden on a user of the sonic electric toothbrush at introduction of the water flow type oral cavity cleaning device. 
         [0019]    The first shaft member and the nozzle can be arranged in a coaxial line. In general, the first shaft member is arranged coaxially with a replacement brush of a sonic electric toothbrush. The nozzle of the water flow type oral cavity cleaning device, is supposed to be inserted into an oral cavity of a user for use as with the replacement brush. Therefore, the nozzle can be enhanced in operability at use of the water flow type oral cavity cleaning device by arranging the first shaft member and the nozzle in a coaxial line to meet the same positional relationship as that of the first shaft member and the replacement brush. 
         [0020]    A pump and a cleaning liquid tank can be provided above a handling grip part. Although the cleaning liquid tank may be provided at the grip part or under the same, the cleaning liquid has a larger pressure loss in the course from the cleaning liquid tank to the pump and in the course from the pump to the nozzle. Therefore, the pump and the cleaning liquid tank are preferably provided above the handling grip part. 
         [0021]    In another preferred embodiment, a drive unit of an electric toothbrush including a drive shaft as the first shaft member making a reciprocating linear motion, is detachably provided as the drive means main body to a cleaning device main body having the pump, the discharge nozzle, and the vibrational frequency adjustment device, and a power transfer attachment transferring power of the drive unit to the first conversion means, is provided, the power transfer attachment including: a power transfer member that has a fitting part fitted and fixed detachably to the first shaft member of the drive unit and transfers power of the first shaft member to the first conversion means; and position adjustment means that moves the drive unit and the cleaning device main body relatively in an axial direction of the first shaft member, thereby to adjust the current position of a reciprocating linear motion of the power transfer member moving together with the first shaft member of the drive unit with respect to the cleaning device main body to a position adapted to the current position of a reciprocating motion of the first shaft member with respect to the drive unit. 
         [0022]    In this case, the first shaft member formed by the drive shaft of the drive unit of the electric toothbrush is fitted and fixed to the fitting part of the power transfer member of the attachment, and power of the first shaft member is transferred via the power transfer member to the cleaning device main body. When the first shaft member is inserted and fitted into the fitting part of the power transfer member, even if the power transfer member is pressed and moved toward a top dead point, the position adjustment means allows the drive unit and the cleaning device main body to move relatively in the axial direction of the first shaft member, and the current position of a reciprocating linear motion of the power transfer member moving together with the first shaft member with respect to the cleaning device main body is adjusted to a position adapted to the current position of a reciprocating linear motion of the first shaft member with respect to the drive unit. Accordingly, the reciprocating linear motion of the first shaft member with respect to the drive unit and the reciprocating linear motion of the power transfer member with respect to the cleaning device main body, are synchronized. 
         [0023]    As in the foregoing, the power transfer attachment allows the position adjustment means to synchronize by a one-touch operation a reciprocating linear motion of the first shaft member with respect to the drive unit and a reciprocating linear motion of the power transfer member with respect to the cleaning device main body. This makes it possible to eliminate an adjustment for synchronization and allow the water flow type oral cavity cleaning device to be used only by fitting the first shaft member into the fitting part of the power transfer member. 
         [0024]    If using the thus configured power transfer attachment, in a preferred embodiment, the first conversion means is provided with a lever member converting a reciprocating linear motion of the first shaft member into a reciprocating rotational motion of the input-side rotational member, and the power transfer member is coupled to an end part of the lever member. In this case, adjusting a lever length of the lever member makes it possible to adjust the angle of a reciprocating rotational motion of the input-side rotational member at a reciprocating linear motion of the first shaft member and regulate the ratio between vibrational frequency of the first shaft member and vibrational frequency of the second shaft member. 
         [0025]    In addition, the position adjustment means may include first bias means that is compressed by a fitting operation of the first shaft member into the fitting part to bias the drive unit in a direction of separation of the first shaft member; and a positioning means that locks movement of the drive unit by the first bias means in the direction of separation and places the drive unit in an appropriate position with respect to the cleaning device main body. In this case, the first shaft member can be reliably fitted and fixed to the fitting part by fitting the first shaft member to the fitting part of the power transfer member while compressing the first bias means. In addition, after the fitting of the first shaft member, the drive unit is moved together with the first shaft member and the power transfer member in the direction separation of the first shaft member by a bias force of the first bias means, the drive unit is placed by the positioning means in a position appropriate with respect to the cleaning device main body, and the current position of a reciprocating linear motion of the power transfer member with respect to the cleaning device main body is adjusted to a position adapted to the current position of a reciprocating linear motion of the first shaft member with respect to the drive unit. Accordingly, the reciprocating linear motion of the first shaft member with respect to the drive unit and the reciprocating linear motion of the power transfer member with respect to the cleaning device main body, are synchronized, are synchronized. 
         [0026]    In another preferred embodiment, second bias means is provided to bias the power transfer member making a reciprocating linear motion together with the first shaft member to a central position of a reciprocating linear motion of the power transfer member. Providing the second bias means is preferred in stabilizing an operation of the power transfer member. 
         [0027]    A guide part guiding the drive unit movably only in a direction of fitting of the first shaft member to the fitting part, may be provided. In this case, moving the drive unit along the guide part makes it possible to facilitate insertion and extraction of the first shaft member from and into the fitting part. 
       Advantageous Effects of Invention 
       [0028]    In the vibrational frequency adjustment device of the present invention, the vibrational frequency of the second shaft member can be adjusted inexpensively and reliably by employing the first conversion means of a simple mechanical configuration having a one-way clutch. In addition, the second conversion means uses a crank mechanism, a cam mechanism, or the like, to convert a rotational motion of the output-side rotational member into a reciprocating motion of the second shaft member. The second conversion means also allows the amplitude of the second shaft member to be arbitrarily adjusted. 
         [0029]    In the water flow type oral cavity cleaning device of the present invention, the vibrational frequency adjustment device makes it possible to arbitrarily adjust the vibrational frequency and amplitude of a reciprocating linear motion of the second shaft member. This makes it possible to adjust a reciprocating linear motion of the first shaft member vibrating at a high speed to a low-speed reciprocating linear motion of the second shaft member, and use a drive unit of a sonic electric toothbrush also as the drive means main body of the water flow type oral cavity cleaning device. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0030]      FIG. 1  is a perspective view of a water flow type oral cavity cleaning device; 
           [0031]      FIG. 2  is a cross section view of the water flow type oral cavity cleaning device at a placement position of a nozzle; 
           [0032]      FIG. 3  is a diagram for describing an attachable/detachable part of the water flow type oral cavity cleaning device; 
           [0033]      FIG. 4  is a cross section view of the water flow type oral cavity cleaning device at a placement position of a gear; 
           [0034]      FIG. 5  is a diagram for describing an operation of a vibrational frequency adjustment device and a pump in the water flow type oral cavity cleaning device; 
           [0035]      FIG. 6(   a ) is a cross section view of  FIG. 5  taken along line a-a, and  FIG. 6(   b ) is a cross section view of  FIG. 5  taken along line b-b; 
           [0036]      FIG. 7  is a diagram for describing an operation of a vibrational frequency adjustment device and a pump in the water flow type oral cavity cleaning device; 
           [0037]      FIGS. 8(   a ) to  8 ( c ) are diagrams for describing an operation of an attachment; 
           [0038]      FIG. 9(   a ) is a plan view of a coupling tube,  FIG. 9(   b ) is a cross section view of the same taken along line b-b,  FIG. 9(   c ) is a bottom view of the same, and  FIG. 9(   d ) is a perspective view of the same; and 
           [0039]      FIG. 10(   a ) is a plan view of a pressure tube,  FIG. 10(   b ) is a cross section view of the same taken along line b-b,  FIG. 10(   c ) is a bottom view of the same, and  FIG. 10(   d ) is a perspective view of the same with a front half part cut out. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0040]    An embodiment for carrying out the present invention will be described below with reference to the drawings. 
         [0041]    As shown in  FIGS. 1 to 4 , a water flow type oral cavity cleaning device  1  includes a cleaning device main body  2 , and a drive unit  3  as a drive means main body detachably attached to a front side of the cleaning device main body  2 , in which a drive unit of a sonic electric toothbrush is used also as the drive unit  3  of the water flow type oral cavity cleaning device  1 . In the following description of this embodiment, a side of the device on which the drive unit  3  is attached is defined as a front side. 
         [0042]    The drive unit  3  includes a drive shaft  10  (equivalent to a first shaft member) supported so as to be capable of a reciprocating linear motion; a motor  12  driven by a battery  11 ; and a scotch yoke mechanism  13  that converts a rotational motion of a rotation shaft  12   a  of the motor  12  into a reciprocating linear motion of the drive shaft  10 . The drive unit  3  is configured in the same manner as a drive unit of a well-known sonic electric toothbrush, where a replacement brush (not shown) can be detachably attached to an upper end portion of the drive shaft  10 , and the drive shaft  10  makes one reciprocating motion each time the rotation shaft  12   a  makes one rotation by the scotch yoke mechanism  13 . However, the drive unit  3  may be used as a drive unit of an arbitrarily configured sonic electric toothbrush with an increased vibrational frequency of the drive shaft  10  by combining a plurality of gears or by the use of a linear actuator having a permanent magnet and a coil, or may be used as a drive unit of a motor-powered electric toothbrush with a low vibrational frequency of the drive shaft  10  of 1,500 to 5,000 cpm, as far as the drive unit  3  is configured to allow the drive shaft  10  to make a reciprocating linear motion. 
         [0043]    As shown in  FIGS. 1 to 7 , the cleaning device main body  2  includes: a power transfer attachment  60  that transfers power of the drive shaft  10  of the drive unit  3  to the cleaning device main body  2  via a power transfer member  61 ; a pump  21  that is capable of discharging a cleaning liquid by a reciprocating linear motion of a piston  20 ; vibrational frequency adjustment means  22  that switches a reciprocating linear motion of the power transfer member  61  to a reciprocating linear motion of the piston  20  with a vibrational frequency and an amplitude adapted to the pump  21 ; a cleaning liquid tank  23  storing the cleaning liquid; and a discharge nozzle  24  for the cleaning liquid. The cleaning device main body  2  is configured to clean interdental gaps, tooth surfaces, periodontal pockets, and the like, by the cleaning liquid discharged intermittently from the discharge nozzle  24 . The vibrational frequency adjustment means  22  is equivalent to the vibrational frequency adjustment device, and the vibrational frequency adjustment means  22  and the drive unit  3  are equivalent to the pump drive means. 
         [0044]    Formed on an upper part of a frame  25  of the cleaning device main body  2  is a U-shaped and horseshoe-like base part  26  in a planar view over which the cleaning liquid tank  23  is detachably fitted. Formed under the frame  25  is a grip part  27  extending to a lower end of the drive unit  3  along a back side of the same. The grip part  27  is configured to improve operability of the cleaning device  1  by gripping by hand the drive unit  3  together with the grip part  27 . 
         [0045]    The discharge nozzle  24  is formed by a well-known, hollow and pipe-like discharge nozzle for water pickup, and is detachably attached to an upper end of the base part  26  in a liquid-tight manner so as to be coaxial with the drive shaft  10 . 
         [0046]    The pump  21  includes a circular cylinder  30  provided in an up-down direction within a lower portion of the base part  26 ; the piston  20  fitted into the cylinder  30  in a liquid-tight manner so as to be capable of up-down movement; and a valve member  32  capable of opening and closing an entrance part  31  at a lower end portion of the cylinder  30 . The pump  21  is connected to a supply tube  33  allowing a lower end of the cleaning liquid tank  23  and the entrance part  31  of the cylinder  30  to communicate with each other, and is connected to a discharge tube  35  allowing an exit part  34  at a lower part of the cylinder  30  and the discharge nozzle  24  to communicate with each other. When the piston  20  moves upward, the valve member  32  is opened and the cleaning liquid in the cleaning liquid tank  23  is supplied to the cylinder  30  through the supply tube  33 . When the piston  20  moves downward, the valve member  32  is closed and the cleaning liquid in the cylinder  30  is discharged from the discharge nozzle  24  through the discharge tube  35 . 
         [0047]    The vibrational frequency adjustment means  22  includes first conversion means  40  that converts a reciprocating linear motion of the power transfer member  61  making a reciprocating linear motion together with the drive shaft  10  into a rotational motion of an output-side rotational member  42  in one direction; and second conversion means  50  that converts the rotational motion of the output-side rotational member  42  into a reciprocating linear motion of a second shaft member  43 . 
         [0048]    As shown in  FIGS. 5 to 7 , the first conversion means  40  includes an input-side rotational member  41 ; the output-side rotational member  42 ; and a one-way clutch  44  that transfers a rotational motion of the input-side rotational member  41  only in one direction to the output-side rotational member  42 . The input-side rotational member  41 , the output-side rotational member  42 , and the one-way clutch  44  are rotatably supported via a support shaft  45  in an upper back portion of the base part  26 . 
         [0049]    The first conversion means  40  will be described below. The first conversion means  40  is provided with the ring-like one-way clutch  44  of a well-known configuration in which a plurality of axially extending rollers (not shown) is circumferentially arranged on an inner peripheral part so as to appear at specific intervals; an input-side sleeve  41   a  over which the one-way clutch  44  is fitted is formed to project at a central part of the disc-like input-side rotational member  41 ; and an output-side sleeve  42   a  fitted over the one-way clutch  44  and formed to project in the proximity of an outer periphery of the disc-like output-side rotational member  42 . The input-side rotational member  41  is fitted into the one-way clutch  44  so as to be incapable of relative rotation in a direction shown by arrow A and be capable of relative rotation in a direction opposite to the direction shown by arrow A. The output-side rotational member  42  is fitted over the one-way clutch  44  so as to be incapable of relative rotation via a projection  42   b  projecting on an inner peripheral surface of the output-side rotational member  42 . In addition, at rotation of the input-side rotational member  41  in the direction of arrow A, the output-side rotational member  42  rotates together with the input-side rotational member  41  via the one-way clutch  44 , and a rotating force of the input-side rotational member  41  is transferred to the output-side rotational member  42 . At rotation of the input-side rotational member  41  in the direction opposite to arrow A, only the input-side rotational member  41  rotates, and no rotating force is transferred to the output-side rotational member  42  via the one-way clutch  44 . 
         [0050]    A lever member  47  extending in a front-back direction is provided at an upper portion of the base part  26 , so as to be rotatable about a horizontal pivotal support shaft  46 . A front end portion of the lever member  47  is rotatably coupled to the power transfer member  61  capable of being integrally fitted over the drive shaft  10  via a pin member  48 , a middle portion of the lever member  47  has a frame portion  47   a  avoiding contact with a support shaft  45  of the first conversion means  40 , and a back end portion of the lever member  47  has a horizontally elongated long hole  47   b.  An operation pin  49  is raised and fixed so as to be fitted into the long hole  47   b  in the proximity of an outer periphery of the input-side rotational member  41 . When the lever member  47  rotates about the pivotal support shaft  46  by a reciprocating linear motion of the drive shaft  10  in an up-down direction, the amplitude of the drive shaft  10  is amplified depending on the ratio of a length L 1  between the pivotal support shaft  46  and the operation pin  49  and a length L 2  between the pivotal support shaft  46  and the pin member  48 , and the back end portion of the lever member  47  makes a reciprocating motion in the up-down direction. Then, when the input-side rotational member  41  makes a reciprocating rotational motion by an angle corresponding to the amplitude of the back end portion of the lever member  47  as shown by arrow B, the output-side rotational member  42  rotates via the one-way clutch  44  by each specific angle in the direction of arrow A. However, the long hole  47   b  may be formed in the input-side rotational member  41 , and the operation pin  49  may be provided at the lever member  47 . 
         [0051]    The second conversion means  50  will be described below. A first gear  51  is formed at an outer peripheral portion of the output-side rotational member  42 , and a second gear  52  engaging with the first gear  51  is supported at a lower side of the output-side rotational member  42  so as to rotatable about the pin member  53 , and a cylindrical eccentric cam  54  is provided at the second gear  52  so as to be eccentric by a specific distance L 3  with respect to the pin member  53 . A tubular part  55  rotatably fitted over the eccentric cam  54  is formed at an upper end portion of the second shaft member  43  driving the piston  20  of the pump  21  in the up-down direction. When the second gear  52  rotates about the pin member  53 , the second shaft member  43  and the piston  20  make a reciprocating linear motion in the up-down direction with an amplitude twice the eccentric distance L 3  of the eccentric cam  54  with respect to the pin member  53 . 
         [0052]    At the oral cavity cleaning device  1 , it is possible to set the ratio between vibrational frequency of the first shaft member and the vibrational frequency of the second shaft member  43  depending on the ratio between lengths L 1  and L 2  of the lever member  47  of the first conversion means  40 , a distance L 4  between the operation pin  49  and the support shaft  45 , and the ratio of number of teeth between the first gear  51  and the second gear  52 . In addition, the amplitude of a reciprocating linear motion of the piston  20  is twice larger than the eccentric distance L 3  of the eccentric cam  54 . Therefore, it is possible to use a drive unit of a sonic electric toothbrush also as the drive unit  3  of the water flow type oral cavity cleaning device  1 , even if the drive shaft  10  has a vibration frequency of is 5,000 to 11,000 cpm and an amplitude of 0.2 to 1.0 mm. However, the pump  21 , the vibrational frequency adjustment means  22 , the cleaning liquid tank  23 , and the discharge nozzle  24  may be configured in manners other than those shown in  FIGS. 1 to 7 . 
         [0053]    As shown in  FIGS. 1 to 5  and  7  to  10 , the power transfer attachment  60  has a fitting part  62  detachably fitted and fixed to the drive shaft  10  of the drive unit  3 , and includes a power transfer member  61  transferring power of the drive shaft  10  to the cleaning device main body  2 ; and position adjustment means  63  that moves the drive unit  3  and the cleaning device main body  2  relatively in an axial direction (up-down direction) of the drive shaft  10  and adjusts the current position of a reciprocating linear motion of the power transfer member  61  moving together with the drive shaft  10  of the drive unit  3  to a position adapted to the current position of a reciprocating linear motion of the drive shaft  10  with respect to the drive unit  3 . 
         [0054]    The position adjustment means  63  includes: a pair of right and left guide parts  64  guiding the drive unit  3  movably only in the up-down direction; first bias means  65  that is compressed by a fitting operation of the drive shaft  10  to the fitting part  62  to bias the drive unit  3  in a direction of separation of the drive shaft  10  (downward in  FIG. 5 ); and positioning means  66  that locks movement of the drive unit  3  by the first bias means  65  in the direction of separation and places the drive unit  3  in an appropriate position with respect to the cleaning device main body  2 . 
         [0055]    The guide parts  64  are formed to project forward in an arc-like shape from the right and left sides of the grip part  27  along the drive unit  3  arranged in front of the grip part  27  of the cleaning device main body  2 . The drive unit  3  is guided movably only in the up-down direction when being inserted between the right and left guide parts  64  from underneath. However, the guide parts  64  may be omitted. 
         [0056]    The first bias means  65  will be described below. As shown in  FIGS. 5 , and  7  to  10 , a downwardly projecting support tubular part  67  is integrally formed on a lower surface of the front portion  26   a  of the base part  26  opposed to the drive unit  3 . The support tubular part  67  has hook parts  67   a  circumferentially spaced at a heightwise middle portion, and a downwardly extending coupling tube  68  is fitted over and fixed to fitting concave parts  68   a  so as to be engaged with the hook parts  67   a  and be incapable of moving in the up-down direction. An O-ring  69  is intervened between a base end portion of the support tubular part  67  and an upper end portion of the coupling tube  68 , and the coupling tube  68  is fitted over the support tubular part  67  via the O-ring  69  in watertight manner. 
         [0057]    The power transfer member  61  is provided so as to pass through vertically central portions of the support tubular part  67  and the coupling tube  68 . The coupling tube  68  has inwardly projecting annular holding parts  68   b  at a lower end portion thereof, second bias means  70  formed by a disc-like rubber member is provided between the holding part  68   b  and a lower end portion of the support tubular part  67 . A middle portion of the power transfer member  61  penetrates through and is fixed to central portion of the second bias means  70 . The second bias means  70  biases the power transfer member  61  constantly to a central position of a reciprocating linear motion, and closes gaps between the support tubular part  67  and the power transfer member  61  and between the coupling tube  68  and the power transfer member  61 , in a water-tight manner. 
         [0058]    An annular groove  68   c  is formed in an outer peripheral surface of the coupling tube  68  at a heightwise middle portion, and three vertically extending guide grooves  68   d  are spaced circumferentially in the outer peripheral surface of the coupling tube  68 . A cylindrical pressure tube  71  is fitted over the coupling tube  68  movably in the vertical direction. Engagement projections  71   a  are formed in an inner peripheral surface of the pressure tube  71  so as to engage with the annular groove  68   c  movably in the vertical direction. Projecting rails  71   b  are circumferentially spaced in the internal peripheral surface of the pressure tube  71  so as to be fitted into the guide grooves  68   d.  The pressure tube  71  is externally attached to the coupling tube  68  so as to be incapable of relative movement in a circumferential direction and be capable of vertical movement by a groove width of the annular groove  68   c.  An inwardly extending annular reception part  71   c  is formed at a lower end portion of the pressure tube  71 . A spring member  72  biasing the pressure tube  71  constantly downward is provided between the holding part  68   b  of the coupling tube  68  and the reception part  71   c  of the pressure tube  71 . Alternatively, in place of the spring member  72 , synthetic rubber such as urethane rubber or a cushion material such as an air cushion, can be provided. 
         [0059]    The positioning means  66  will be described below. As shown in  FIGS. 1 to 4 , a lock concave part  73  is formed in a front surface of a lower portion of the grip part  27 , a projection  74  to be fitted to the lock concave part  73  is formed in a back surface of the casing  14  of the drive unit  3 . When the projection  74  is fitted to the lock concave part  73 , the drive unit  3  is placed at the cleaning device main body  2  in an appropriate position along an axial direction (height direction) of the drive shaft  10 . A bracket part  27   a  is formed to project backward at a lower end portion of the grip part  27 . A holder member  75  capable of holding the lower end portion of the drive unit  3  is supported at the bracket part  27   a  so as to rotatable about the pivotal support pin  76 , ranging from a holding position shown in  FIG. 2  to an opening position shown in  FIG. 3 . A twisted spring  79  is externally attached to the pivotal support pin  76  between the bracket part  27   a  and the holder member  75 , and the holder member  75  is constantly biased toward the opening position via the twisted spring  79 . A release button  77  is provided at the bracket part  27   a  so as to be movable in the up-down direction, and the release button  77  is constantly biased upward by a spring member  78 . The holder member  75  has an engagement pawl  75   a,  and the release button  77  has a lock hole  77   a  in which the engagement pawl  75   a  can be locked. When the holder member  75  is operated so as to move from the opening position shown in  FIG. 3  to the holding position, the engagement pawl  75   a  engages in the lock hole  77   a,  the holder member  75  is held at the holding position, and the lower end portion of the drive unit  3  is held so as not to move downward or forward with respect to the holder member  75 , so that the projection  74  does not come off from the lock concave part  73 , as shown in  FIG. 2 . Meanwhile, when the release button  77  is pressed, the engagement pawl  75   a  is disengaged from the lock hole  77   a  as shown in  FIG. 4 , and the holder member  75  rotates into the opening position by a biasing force of the twisted spring  79 , as shown in  FIG. 3 , whereby the drive unit  3  can be attached to or detached from the cleaning device main body  2 . 
         [0060]    In the power transfer attachment  60 , when the drive unit  3  is not assembled into the cleaning device main body  2 , the pressure tube  71  is projected downward by the first bias means  65 , and the power transfer member  61  is held by the second bias means  70  at a central position of a reciprocating linear motion in the up-down direction, as shown in  FIG. 8  ( a ). In this state, the drive shaft  10  is inserted into the fitting part  62  until the annular groove  30   a  of the drive shaft  10  in the drive unit  3  of the electrical toothbrush is fitted to the annular projection  61   a  of the power transfer member  61  of the attachment  60 , and the power transfer member  61  is pressed upward while the pressure tube  71  is pressed up by the casing  14  of the drive unit  3  to compress the first bias means  65 , whereby the drive shaft  10  is fitted and fixed to the fitting part  62  of the power transfer member  61 , as shown in  FIG. 8  ( b ). At that time, the drive shaft  10  does not move relative to the drive unit  3 , but the power transfer member  61  moves relative to the cleaning device main body  2  toward a top dead point. In addition, in this state, when the drive unit  3  is released, as shown in  FIG. 8  ( c ), the drive unit  3  moves downward by a biasing force of the first bias means  65  until the projection  74  of the casing  14  of the drive unit  3  is locked at the lock concave part  73 , and the power transfer member  61  moves downward together with the drive unit  3 . While the casing  14  of the drive unit  3  is locked at the lock concave part  73 , the current position of a reciprocating linear motion of the power transfer member  61  with respect to the cleaning device main body  2  is adjusted to a position adapted to the current position of a reciprocating linear motion of the drive shaft  10  with respect to the drive unit  3 . Accordingly, synchronization is achieved between the reciprocating linear motion of the drive shaft  10  with respect to the drive unit  3  and the reciprocating linear motion of the power transfer member  61  with respect to the cleaning device main body  2 . 
         [0061]    As described above, in the power transfer attachment  60 , the drive unit  3  of the electric toothbrush can be used also as a drive unit of the cleaning device main body  2 , which makes it possible to use the electric toothbrush and the water flow type oral cavity cleaning device  1  while reducing an economic burden on a user. In addition, the position adjustment means  63  allows synchronization by a one-touch operation between the reciprocating linear motion of the drive shaft  10  with respect to the drive unit  3  and the reciprocating linear motion of the power transfer member  61  with respect to the cleaning device main body  2 . Accordingly, it is possible to eliminate an adjustment task for synchronization and use the cleaning device main body  2  only by fitting the drive shaft  10  to the fitting part  62  of the power transfer member  61 . 
         [0062]    In the embodiment described above, the vibrational frequency adjustment device of the present invention is applied to the vibrational frequency adjustment means  22  of the water flow type oral cavity cleaning device  1 . However, the vibrational frequency adjustment device can also be applied to various devices requiring modification of vibrational frequency or amplitude of a reciprocating linear motion. 
       REFERENCE SIGNS LIST 
       [0063]      1  Water flow type oral cavity cleaning device 
         [0064]      2  Cleaning device main body 
         [0065]      3  Drive unit 
         [0066]      10  Drive shaft 
         [0067]      11  Battery 
         [0068]      12  Motor 
         [0069]      12   a  Rotation shaft 
         [0070]      13  Scotch yoke mechanism 
         [0071]      14  Casing 
         [0072]      20  Piston 
         [0073]      21  Pump 
         [0074]      22  Vibrational frequency adjustment means 
         [0075]      23  Cleaning liquid tank 
         [0076]      24  Discharge nozzle 
         [0077]      25  Frame 
         [0078]      26  Base part 
         [0079]      26   a  Front part 
         [0080]      27  Grip part 
         [0081]      27   a  Bracket part 
         [0082]      30  Cylinder 
         [0083]      30   a  Annular groove 
         [0084]      31  Entrance part 
         [0085]      32  Valve member 
         [0086]      33  Supply tube 
         [0087]      34  Exit part 
         [0088]      35  Discharge tube 
         [0089]      40  First conversion means 
         [0090]      41  Input-side rotational member 
         [0091]      41   a  Input-side sleeve 
         [0092]    Output-side rotational member 
         [0093]      42   a  Output-side sleeve 
         [0094]      42   b  Projection 
         [0095]      43  Second shaft member 
         [0096]      44  One-way clutch 
         [0097]      45  Support shaft 
         [0098]      46  Pivotal support shaft 
         [0099]      47  Lever member 
         [0100]      47   a  Frame part 
         [0101]      47   b  Long hole 
         [0102]      48  Pin member 
         [0103]      49  Operation pin 
         [0104]      50  Second conversion means 
         [0105]      51  First gear 
         [0106]      52  Second gear 
         [0107]      53  Pin member 
         [0108]      54  Eccentric cam 
         [0109]      55  Tubular part 
         [0110]      60  Power transfer attachment 
         [0111]      61  Power transfer member 
         [0112]      61   a  Annular projection 
         [0113]      62  Fitting part 
         [0114]      63  Position adjustment means 
         [0115]      64  Guide part 
         [0116]      65  First bias means 
         [0117]      66  Positioning means 
         [0118]      67  Support tubular part 
         [0119]      67   a  Hook part 
         [0120]      68  Coupling tube 
         [0121]      68   a  Fitting concave part 
         [0122]      68   b  Holding part 
         [0123]      68   c  Annular groove 
         [0124]      68   d  Guide groove 
         [0125]      69  Ring 
         [0126]      70  Second bias means 
         [0127]      71  Pressure tube 
         [0128]      71   a  Engagement projection 
         [0129]      71   b  Projecting rail 
         [0130]      71   c  Reception part 
         [0131]      72  Spring member 
         [0132]      73  Lock concave part 
         [0133]      74  Projection 
         [0134]      75  Holder member 
         [0135]      75   a  Engagement pawl 
         [0136]      76  Pivotal support pin 
         [0137]      77  Release button 
         [0138]      77   a  Lock hole 
         [0139]      78  Spring member 
         [0140]      79  Twisted spring