Abstract:
A rotary operation switch including a support body, an operation member rotatably supported by the support body and a switch mechanism provided therebetween to define multiple positions in a rotational direction of the operation member, wherein one of the support body and the operation member defines multiple recesses corresponding to the multiple positions, and wherein the rotary operation switch includes: a movable engaging body formed of a permanent magnet or a magnetic material and provided on the other of the support body and the operation member to engage with or disengage from the recesses as the operation member is rotated; a guiding portion provided on the other of the support body and the operation member to guide the engaging body; and a magnetic attractive force generation portion provided on the one of the support body and the operation member to exert magnetic attractive force on the engaging body.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a rotary operation switch and a strobe device including the same, and in particular to a rotary operation switch which provides a click feeling at contact positions when a rotating operation is carried out, and a strobe device including the same. 
       BACKGROUND OF THE INVENTION 
       [0002]    Conventionally, cameras, strobe devices or the like may be provided with a rotary operation switch having a dial-type rotary operation member which has a terminal attached thereto and which is rotatable to set various conditions. Some of such rotary operation switches are configured to provide a click feeling to allow a user to know that the rotary operation switch has reached a setting position when the rotary operation switch is operated manually (refer to JP 2011-146358A, for instance). 
         [0003]    The operation switch of JP 2011-146358A includes a cylindrical plunger coaxial with the rotary operation member which is to be manually operated. The cylindrical plunger is provided with a side hole extending in a horizontal direction or perpendicularly to an axial direction. The side hole is provided therein with a coil spring which urges outwardly from the inside of the plunger a pair of balls provided at either end of the coil spring. The rotary operation member is provided with a plunger insertion hole extending in the axial direction and the inner circumference of the plunger insertion hole is formed as a corrugated surface, so that when the rotary operation member is rotated for an operation, the balls urged by the coil spring move along the side hole forwardly and backwardly following the corrugated surface, whereby the rotational resistance of the rotary operation member is varied and a click feeling is obtained. 
       SUMMARY OF THE INVENTION 
       [0004]    However, in the operation switch of JP 2011-146358A, since the balls are urged by the coil spring and pushed onto the corrugated surface for obtaining a click feeling, it is necessary during assembly to insert the plunger into the plunger insertion hole of the rotary operation member while the balls are pressed into the side hole against the urging force of the coil spring. It is preferable that the coil spring exert a large urging force for obtaining a strong click feeling. However, in that case, the force urging the balk becomes large and, since it becomes necessary to assemble the plunger into the plunger insertion hole of the rotary operation member while pressing the balls inside the side hole of the plunger against the large urging force, assembling workability is lowered. In addition, when the plunger is removed for a repair, if the balls are not properly held, the balls may be scattered by the urging force of the coil spring. 
         [0005]    To solve such problems and to realize a rotary operation switch which provides a strong click feeling and which can improve assembling and disassembling workability and a strobe device including such a rotary operation switch, the present invention provides a rotary operation switch including a support body ( 12 ), a rotary operation member ( 31 ) rotatably supported by the support body and a switch mechanism ( 55 ,  56 ,  57 ) provided between the rotary operation member and the support body to define a plurality of positions in a rotational direction of the rotary operation member, wherein one of the support body and the rotary operation member defines a plurality of recesses ( 42 ) corresponding to the plurality of positions in the rotational direction of the rotary operation member, and wherein the rotary operation switch includes: a movable engaging body ( 42 ) formed of a permanent magnet or a magnetic material and provided on the other of the support body and the rotary operation member such that the movable engaging body is moveable in a direction intersecting the rotational direction to engage with or disengage from the recesses as the rotary operation member is rotated; a guiding portion ( 61 ) provided on the other of the support body and the rotary operation member such that the guiding portion guides the movable engaging body in the direction intersecting the rotational direction; and a magnetic attractive force generation portion ( 32 ) provided on the one of the support body and the rotary operation member such that the magnetic attractive force generation portion exerts magnetic attractive force on the movable engaging body. 
         [0006]    According to this structure, in the rotary operation switch provided with a switch mechanism for detecting a plurality of positions, when the rotary operation member is rotated, the movable engaging body engages with the recesses one by one to provide a click feeling. In addition, since the engagement between the movable engaging body and the recesses is achieved by magnetic attractive force, it is possible to handle the movable engaging body integrally with the rotary operation member by having the movable engaging body attached to the recess with magnetic attractive force. Thus, unlike the conventional structure where a coil spring is employed to provide urging force, there is no need to hold the movable engaging body against the urging force of the coil spring when handling the movable engaging body, and thus, the assembling workability is improved. 
         [0007]    Preferably, the moving engaging body consists of a spherical body, and each recess to be engaged with the movable engaging body defines a circular opening having a diameter smaller than that of the spherical body. 
         [0008]    If an urging force were provided to the movable engaging body by a coil spring as in the conventional structure, the spherical movable engaging body may contact the edge of the circular opening of each recess only partially due to a deflection of the spring coil. However, according to this structure, the movable engaging body and the recess abut each other along the entire edge of the circular opening owing to the magnetic attractive force, and thus, it is possible to always achieve a stable engaged state. When the movable engaging body disengages from one recess and engages the next recess as the rotary operation member is rotated, the spherical movable engaging body can freely roll, and thus, the rotary operation member can be rotated smoothly without being subject to high resistance. 
         [0009]    It is also preferable that the guiding portion is configured to guide the movable engaging body in a direction parallel to an axis of rotation of the rotary operation member, and that each recess opens in a direction perpendicular to the rotational direction of the rotary operation member. 
         [0010]    According to this structure, the movable engaging body moves with respect to each recess in the direction intersecting the rotational direction of the rotary operation member, and a resistance against the operation of the rotary operation member in the rotational direction is obtained when the movable engaging body and the recess engage each other. When the rotary operation member is rotated against the resistance and the movable engaging body comes into point contact with a plate-like portion (i.e., a portion free of the recesses) of the one of the support body and the rotary operation member, the resistance is lowered and the rotational operation can be carried out easily. 
         [0011]    It is also preferable that the guiding portion is provided on the support body and is composed of a through hole having the movable engaging body inserted therein. 
         [0012]    According to this structure, it is possible to insert the movable engaging body into the guiding portion from the side opposite to the rotary operation member even after the rotary operation member is assembled with the support body, whereby there is no restriction in assembly and workability can be improved. 
         [0013]    Thus, according to the present invention, in the rotary operation switch provided with a switch mechanism for detecting a plurality of positions, when the rotary operation member is rotated, the movable engaging body engages with the recesses one by one and provides a click feeling. In addition, since the engagement between the movable engaging body and the recesses is achieved by magnetic attractive force, it is possible to handle the movable engaging body integrally with the rotary operation member by having the movable engaging body attached to the recess with magnetic attractive force. Thus, unlike the conventional structure where a coil spring is employed to provide urging force, there is no need to hold the movable engaging body against the urging force of the coil spring when handling the movable engaging body, and thus, the assembling workability is improved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Now the present invention is described in the following in terms of preferred embodiments thereof with reference to the appended drawings, in which: 
           [0015]      FIG. 1  is a perspective view of a strobe device according to an embodiment of the present invention as seen from a front side; 
           [0016]      FIG. 2  is a perspective view of the strobe device according to the present embodiment as seen from a rear side; 
           [0017]      FIG. 3  is an exploded perspective view of main parts of a number setting dial to which the present invention is applied; 
           [0018]      FIG. 4  is a perspective view showing a back side of a rotary operation member of the number setting dial, with a plate body being attached to the rotary operation member; and 
           [0019]      FIG. 5  is a cross sectional view showing an. assembled state of the number setting dial taken along line V-V in  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    In the following, an embodiment of a strobe device according to the present invention will be described with reference to  FIGS. 1-5 . 
         [0021]    As shown in  FIGS. 1 and 2 , the strobe device  10  includes a lower strobe main body  12  as a support body and an upper strobe main body  14  which is attached to an upper portion of the lower strobe main body  12  so as to be pivotable around a vertical axis and a horizontal axis. 
         [0022]    The lower strobe main body  12  has a mounting portion  16  at its lower bottom to be mounted to a camera (not shown) and contains a battery case, electrical components, a control circuit, etc. therein. A rear portion  13  of the lower strobe main body  12  is provided with a power switch button  18 , a power indicator  20 , a mode selection dial  22  and a number setting dial  24 . 
         [0023]    The upper strobe main body  14  includes an internal flash light source such as a xenon discharge tube and has a light emitting surface  26  composed of a Fresnel lens at a front portion thereof. The upper strobe main body  14  includes a wide angle diffuser panel  28  which is storable at a lower side of the light emitting surface  26  and a plate-like reflector (a reflector board)  30  which is storable at an upper side of the light emitting surface  26 . 
         [0024]      FIG. 3  is an exploded perspective view of main parts of the number setting dial  24  employing the present invention. The number setting dial  24  includes a disc-like rotary operation member  31  which is to be rotated for manual operation and a plate body  32  which is fixed on the back side (facing the rear portion  13  of the lower strobe main body  12 ) of the rotary operation member  31  as is also shown in  FIG. 4 . In the illustrated example, the rotary operation member  31  is formed by molding synthetic resin material and the plate body  32  is formed as a magnetic attractive force generation portion by press forming a thin plate-like magnetic body. 
         [0025]    The rear portion  13  of the lower strobe main body  12  is provided with a circular recess  13   a  for receiving substantially the half of the rotary operation member  31  in its axial direction. A cylindrical boss  33  protrudes from the center of a bottom surface of the recess  13   a.  As shown in  FIG. 4 , the back side of the rotary operation member  31  is composed of a generally flat bottom surface  34  and an annular circumferential wall portion  35  which is provided at an outer circumference of the bottom surface  34 . A cylindrical shaft portion  36  protrudes from the center of the bottom surface  34  and the shaft portion  36  is received and rotatably supported by the boss  33 . 
         [0026]    It is to be noted that, as shown in  FIG. 5 , by screwing a screw  37  into an axial hole of the shaft portion  36  when the shaft portion  36  is supported by the boss  33 , the rotary operation member  31  is attached to the rear portion  13  of the lower strobe main body  12 . 
         [0027]    The plate body  32  is provided at its center with a hole  41  having a size for receiving the boss  33  therein, a plurality of index holes  42  composed of through-holes which are arranged circumferentially, for example, at regular intervals in an outer peripheral part of the plate body  32 , and fixing holes  43  placed between the hole  41  and index holes  42  (three fixing holes  43  in the illustrated example). The index holes  42  serve as recesses of the present invention. The plate body  32  is also provided with a radial notch  44  which has a shape of a slit extending from the outer circumference of the plate body  32  in the radially inward direction, a terminal mounting opening  45  and a terminal positioning opening  46 . 
         [0028]    The bottom surface  34  of the rotary operation member  31  is provided with three protrusions  51  at positions corresponding to those of the three fixing holes  43 , a ridge  52  extending in the radial direction at a position corresponding to that of the radial notch  44 , a protrusion  53  at a position corresponding to that of the terminal mounting opening  45  and a ridge  54  extending in the circumferential direction at a position corresponding to that of the terminal positioning opening  46 . The hole  41  of the plate body  32  is fitted over the boss  33  and the radial notch  44  of the plate body  32  is engaged with the ridge  52  so that the plate body  32  is circumferentially positioned with respect to the rotary operation member  31 , and in this state, an exposed end of each protrusion  51  passing through the corresponding fixing hole  43  is expanded by a tool (not shown), whereby the plate body  32  is fixed to the bottom surface  34  of the rotary operation member  31 . 
         [0029]    As shown in  FIGS. 3 and 4 , a terminal  55  is formed to have an arc-shape extending along the rotational direction of the rotary operation member  31  (arrow A in  FIG. 3 ). The terminal  55  is provided with a fixing hole  55   a  at one end in the direction of extension of the terminal  55  and the other end of the terminal  55  is formed to have a bifurcated fork shape whose extended ends constitute a pair of contact portions  55   b.  The terminal  55  formed in this manner is fixed to the bottom surface  34  of the rotary operation member  31  by aligning the fixing hole  55   a  with the terminal mounting opening  45  of the plate body  32  and expanding an end of the protrusion  53  of the rotary operation member  31  by a tool (not shown) after passing the protrusion  53  through the terminal mounting opening  45  and the fixing hole  55   a.  It is to be noted that the ridge  54  of the rotary operation member  31  is placed between the pair of contact portions  55   b  formed in the bifurcated fork shape of the terminal  55 , whereby the terminal  55  is positioned with respect to the rotary operation member  31 . 
         [0030]    The bottom surface of the recess  13   a  is provided with an opening  13   b  which circumferentially extends substantially halfway around the boss  33 . The opening  13   b  exposes arc-shaped conductive patterns  56  and  57  with greater and smaller radii, respectively, formed on a circuit board  58  provided on the back side of the recess  13   a  (inner side of the lower strobe main body  12 ). These conductive patterns  56  and  57  and the terminal  55  constitute a switch mechanism. Each of the conductive patterns  56  and  57  extends in an arc shape coaxial with the boss  33 . The pair of contact portions  55   b  slidably contacts the conductive patterns  56  and  57  when the rotary operation member  31  is rotated. In the illustrated example, the conductive pattern  56  having a greater radius is divided into multiple parts corresponding to the spacing between the plurality of index holes  42 . 
         [0031]    The bottom surface of the recess  13   a  is provided with a cylindrical guiding portion  61  such that it protrudes toward the plate body  32  at a position where the index holes  42  passes as the rotary operation member  31  is rotated. In the illustrated example, a ball  62  of permanent magnet is received in the cylinder of the cylindrical guiding portion  61  as a movable engaging body. It is to be noted that the inner diameter of the cylindrical guiding portion  61  is set such that the ball  62  can move in the axial direction of the cylindrical guiding portion  61 , namely in the direction in which the ball  62  comes into contact with or disengages from the plate body  32 , smoothly and without rattling. In addition, the index holes  42  are formed in the plate body  32  as through holes each having an inner diameter smaller than the diameter of the ball  62 . It is to be noted that, as shown in  FIG. 5 , the protruding end of the cylindrical guiding portion  61  is configured to come close to the plate body  32  when the rotary operation member  31  is attached to the boss  33 . 
         [0032]    The plurality of index holes  42  are provided such that they correspond to a plurality of values to be set by the number setting dial  24 . For example, for manual settings, nine settings are possible in the range from the maximum. light intensity (1/1) to the minimum light intensity (1/256), and for automatic settings, nine settings are possible in the range from +2.0 to −2.0. It is to be noted that switching between the manual setting and automatic setting is carried out by the mode selection dial  22 . 
         [0033]    In the number setting dial  24  configured in this manner, the cylindrical guiding portion  61  is brought into alignment with the index holes  42  one after another when the rotary operation member  31  is rotated. The ball  62  which is received in the cylindrical guiding portion  61  in freely movable manner in the axial direction of the cylindrical guiding portion  61  is always in contact with the plate body  32  due to the magnetic attractive force between the hall  62  and the plate body  32 . If the cylindrical guiding portion  61  is aligned with one of the index holes  42  as a result of rotating of the rotary operation member  31 , the ball  62  moves into the index hole  42 . Since the diameter of the ball  62  is greater than the inner diameter of the index hole  42 , only a portion of the ball  62  moves into the index hole  42  and the remaining large portion of the ball  62  is held in the cylindrical guiding portion  61 . When the ball  62  moves into the index hole  42 , the spherical surface of the ball  62  abuts the entire circumferential edge of the index hole  42  and the ball  62  is kept in a state where the ball  62  moves into the index hole  42 , and thus, a large resistance against the rotation of the rotary operation member  31  is created and the rotary operation member  31  is stably kept in one of the setting positions. 
         [0034]    If a coil spring were used to urge the ball as in a conventional structure a problem may arise that it is difficult to make the structure compact for such reasons as that a hole for retaining the coil spring therein requires an additional length which tends to increase the thickness of the structure. In contrast, in the illustrated embodiment of the present invention, the urging force is provided as a magnetic force and there is no coil spring used, and hence, the structure can be made compact. Further, in the illustrated embodiment, the strength of click feeling can be adjusted by varying the strength of magnetic attractive force, and thus, the strength of click feeling can be easily changed without changing the external shape of each component part. Thereby, when the rotary operation member  31  is rotated, a sufficient click feeling is achieved each time the ball  62  moves into the index hole  42  and engages therein, and thus, the operation to change settings using the number setting dial  24  can be surely carried out. 
         [0035]    In addition, during assembling work, by placing the ball  62  in the index hall  42 , the ball  62  can be held in and fixed at the index hall  42  due to magnetic attractive force, and therefore, the rotary operation member  31  and the ball  62  can be handled as a unit. Thus, when inserting the shaft portion  36  of the rotary operation member  31  into the boss  33 , it is not necessary to hold the ball  62 , and thus, workability can be improved. 
         [0036]    As shown in  FIG. 5 , the cylindrical guiding portion  61  is formed of a through hole  61   a  extending through the wall of the rear portion  13 , whereby, even after the rotary operation member  31  is assembled with the lower strobe main body  12 , it is possible to mount the ball  62  by inserting the ball  62  through the through hole  61   a  from the back side of the rear portion  13  (the side opposite to the side close to the rotary operation member  31 ) as shown by an arrow B in  FIG. 5 . The ball  62  is attracted and held by the plate body  32  due to magnetic attractive force from the plate body  32  when the ball  62  has been inserted into the through hall  61   a  to some extent. Thus, assembly work of the ball  62  can be easily carried out. 
         [0037]    Further, the position of each index hole  42  is adjusted such that the distance between the ball  62  received in the index hole  42  and the shaft portion  36  is set to be a little smaller than the distance between the inner wall surfaces of the through holes of the boss  33  and cylindrical guiding portion  61 , so that the ball  62  and the shaft portion  36  press the boss  33  and the cylindrical guiding portion  61  in the radial direction when the shaft portion  36  is inserted into the boss  33  and the ball  62  is inserted into the cylindrical guiding portion  61 , whereby the boss  33  and the cylindrical guiding portion  61  are held between the shaft portion  36  and the ball  62 , and thus, the rotary operation member  31  is temporarily fastened to the lower strobe main body  12  even before tightening the screw  37 . This makes the tightening operation of the screw  37  easy. 
         [0038]    Although the present invention has been described in terms of a preferred embodiment thereof in the forgoing, it is obvious to a person skilled in the art that the present invention is not limited to such an embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the foregoing embodiment, the ball  62  is adapted to receive the magnetic attractive force from the index hole  42  aligned therewith in the direction parallel to the direction of the axis (rotational axis) of the rotary operation member  31 . However, it is also possible to provide the rotary operation member  31  with an annular plate body which encircles the outer circumferential surface of the boss  33  and which has index holes each opening in the radial direction and to guide the ball  62  so as to be movable in the radial direction. It is to be noted that not all the structural components in the embodiment described above are necessarily indispensable, but they may be selectively adopted without departing from the spirit of the present invention. 
         [0039]    For example, although, in the above illustrated example, the movable engaging body is embodied as the ball  62  having the shape of a perfect sphere, the movable engaging body may also be embodied as a movable engaging body  63  having the shape of an artillery shell as shown by a two-dot chain line in  FIG. 5 , for example. The movable engaging body  63  is held in a freely movable manner in the axial direction at its cylindrical portion by the cylindrical guiding portion  61  and can achieve an engaged state similar to that of the ball  62  by constructing the protruding end as a semi sphere. 
         [0040]    In addition, although the ball  62  is formed of a permanent magnet and the plate body  32  is formed of magnetic material, conversely, the ball  62  may be formed of magnetic material and the plate body  32  may be formed of a permanent magnet. Furthermore, the plate body  32  may be formed of rigid plastic, for example, and a disk  64  made of a permanent magnet may be embedded in the rotary operation member  31  such that the ball  62  receives the magnetic attractive force from the disk  64 . Conversely, the plate body  32  formed of rigid plastic and the disk  64  formed of a permanent magnet may be provided on the rear portion  13  and the ball  62  formed of magnetic material may he supported by the cylindrical guiding portion  61  provided to the rotary operation member  31 . 
         [0041]    It is to he noted that a strobe device has been described in the foregoing embodiment, but the rotary operation switch according to the present invention is not limited to use in the strobe device. The rotary operation switch is applicable to, for example, setting dials for shutter speed and aperture value of a camera.