Abstract:
A timepiece has a case body and a bezel rotatably and detachably connected to the case body. A ring-shaped guide groove formed in the bezel opposes a ring groove formed in the case body, and a plurality of holding members are slidable in the guide groove into and out of the ring groove to respectively prevent and permit detachment of the bezel from the case body. A plurality of operating screws are screwed into the bezel from an outer side thereof and are rotatably connected at their front end portions to respective holding members. Rotation of the operating screws in tightening and loosening directions moves the holding members into and out of the ring groove.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a timepiece of a wristwatch or the like including a rotatable bezel. 
   2. Related Art 
   In a background art, there is known a wristwatch attached with a rotary bezel at a case body by rotatably fitting the rotary bezel to the case back by making two projected portions caught by each other such that the projected portions provided at an inner periphery of the rotary bezel rides over the projected portion provided at an outer periphery of a ring-like portion of the case body surrounding a transparent cover covering a time display portion to a lower side (refer to, for example, Patent Reference 1). 
   Further, there is known a wristwatch in which in order to attach a rotary bezel to a case body without depending on such a catching structure, a ring-like groove is formed at an outer peripheral face of the rotary bezel fitted to an outer periphery of a ring-like portion of the case body, a pair of engaging members arranged on an outer side of the rotary bezel and in 12 o&#39;clock-6 o&#39;clock directions of the wristwatch are detachably screwed to fasten to the case body, projected portions in a circular arc shape provided at the engaging members are engaged to the ring-like groove of the rotary bezel, thereby, the rotary bezel is made to be able to rotate in the engaging state. The case body of the wristwatch is formed with an outer peripheral wall at a portion thereof which is not arranged with the engaging member, and a surrounding of the rotary bezel is covered by the outer peripheral wall such that the ring-like groove of the rotary bezel is not exposed (refer to, for example, Patent Reference 1). 
   [Patent Reference 1] JP-A-11-118950 (paragraphs 0003-0007, 0020-0038, FIG. 1-FIG. 5) 
   The technology of the latter is excellent in that a drawback of the technology of the former, that is, a drawback of deforming the case body and the rotary bezel in accordance with prying to detach the rotary bezel in maintenance, can be resolved. 
   However, there is the following drawback in the technology of the latter. That is, the surrounding of the rotary bezel is covered by the outer peripheral wall of the case body, and therefore, a thickness for the attachment of the finger in operating to rotate the rotary bezel is obliged to be thinned and, thereby, the operability of the rotary bezel is poor. In addition thereto, the operability of the rotary bezel is poor since in operating to rotate the rotary bezel, since rotation is hampered by touching the finger of a user to the pair of engaging members arranged on the outer side of the rotary bezel. 
   Further, the pair of engaging members screwed to be fastened to the case body are arranged on the outer side of the rotary bezel, and therefore, the engaging members constitute a restriction when the rotary bezel is intended to enlarge from a request in view of design. Therefore, in order to enlarge the rotary bezel, the case back needs to be enlarged inclusively. 
   It is an object of the invention to provide a timepiece which can attach and detach a rotary bezel without being accompanied by a deformation, and can promote a rotation operability of the rotary bezel and does not bring about large-sized formation of a case body when the rotary bezel is enlarged. 
   SUMMARY OF THE INVENTION 
   The invention includes a case body which includes a ring-like portion surrounding a transparent cover and in which a ring-like groove opened to an outer periphery of the ring-like portion is formed at the ring-like portion, a rotary bezel which includes a fitting portion rotatably fitted to the outer periphery of the ring-like portion and arranged to the case body and in which the fitting portion is formed with a guide groove opened to an inner periphery of the fitting portion and opposed to the ring-like groove, at least one piece of an operating screw rotatably attached to the fitting portion by being inserted to the guide groove from an outer side of the rotary bezel, and a holding member connected to a front end portion of the operating screw by permitting rotation of the operating screw, and moved over to a holding position arranged over to the ring-like groove and the guide groove for preventing the rotary bezel from being detached and a release position of being fit into the guide groove by rotating the operating screw. 
   In the invention, the case body and the rotary bezel can be formed by a metal of stainless steel, titanium or the like or a hard synthetic resin or the like. In the invention, a sectional shape of the ring-like groove of the case body and a sectional shape of the guide groove of the rotary bezel can be constituted by a channel-like shape, a semicircular shape, a trapezoidal shape or the like. In the invention, at least one of the guide groove may be provided, and a plurality thereof is preferable. Further, the one guide groove includes a mode of being provided only at one portion in a peripheral direction of the fitting portion other than that the guide groove is constituted by a ring-like shape. Further, the guide groove in the mode of one or more of the guide grooves to be constructed by a constitution of being gradually widened in the peripheral direction of the fitting portion in accordance with proceeding to an opening of the guide groove opened at an inner peripheral face of the fitting portion from the innermost face, or may be constructed by a constitution in which an area of the innermost face and an area of the opening are the same without being widened in this way. 
   In the invention, when one or more of guide grooves other than in a ring-like shape are provided at the fitting portion, the operating screws are used in accordance with a number of the guide grooves. Although when the guide groove is constituted by the ring-like shape, one piece of the operating screw can be used, a plurality of pieces of operating screws may be used and these may be arranged at intervals, preferably, at equal intervals along the peripheral direction of the fitting portion. 
   In the invention, the holding member can be formed by a shape in correspondence with a shape of a ring-like groove of the case body or a shape of the guide groove of the rotary bezel. Further, the holding member can be formed by a metal of stainless steel, titanium or the like or a hard synthetic resin or the like. Along therewith, the holding member may be formed by selecting a material having a small friction resistance with a material forming the case body, for example, when the holding member is formed by a ferrous material in a case in which the case body is made of titanium, the constitution is preferable in that wear of the ring-like groove in accordance with an operation of rotating the rotary bezel can be restrained. 
   In the invention, that the operating screw is attached rotatably to the fitting portion includes a case in which a screw shaft portion of the operating screw is screwed and attached to a screw hole provided at the fitting portion by penetrating the screw hole. Otherwise, there is also included a mode in which the operating screw includes a round shaft portion on a head portion side and a front end portion comprising a screw portion continuous to the screw portion, the round shaft portion of the operating screw is rotatably penetrated to a round hole provided at the fitting portion to communicate with the guide groove, the operating screw is held so as not to be moved in an axial direction by drawout preventing means of a ring-like projected portion projected to, for example, an outer periphery of the round shaft portion and engaged with the innermost face of the guide groove (further, the ring-like projected portion can be inserted to the round hole by press-fitting the operating screw to the round hole), further, a screw hole extended in a horizontal direction is provided at the holding member prevented from being rotated by the guide groove, and by screwing the front end portion comprising the screw portion of the operating screw to the screw hole, the operating screw is rotatably attached to the fitting portion. 
   In the invention, various connection modes can be adopted other than an example explained below by an embodiment in connecting the holding member to the front end portion of the screw by permitting rotation of the operating screw. For example, when the operating screw is rotatably attached to the fitting portion by being screwed, a round horizontal hole penetrating the holding member in the horizontal direction may be provided at the holding member, a round shaft portion constituting a front end portion of the operating screw may be penetrated to the horizontal hole, and by providing drawout preventing means of a stop ring or the like at an outer periphery of the shaft portion, the holding member may be rotatably connected to the front end portion of the operating screw. Or, when the operating screw is attached rotatably to the fitting portion without being screwed, a screw hole extended in a horizontal direction may be provided at the holding member prevented from being rotated by the guide groove, and by screwing the front end portion comprising the screw portion of the operating screw to the screw hole, the holding member may be connected rotatably to the front end portion of the operating screw. 
   In accordance with one aspect of the invention, in order to detach the rotary bezel from the case body, by operating to rotate the operating screw in, for example, a loosening direction such that the holding member is moved in a direction of being drawn out from the ring-like groove of the case body, after making the holding member fit into the guide groove of the rotary bezel to be arranged at the release position, the rotary bezel can be drawn to be detached to the upper side of the case body. Further, in case of integration, in a state in which the holding member is fit into the guide groove of the rotary bezel, after fitting the rotary bezel to the ring-like portion of the case body, by moving the holding member in a direction of being projected from the guide groove by operating to rotate the operating screw in, for example, a fastening direction, the holding member may be arranged at the holding portion at which a portion thereof is inserted to the ring-like groove of the case body. Thereby, the holding member is caught by the ring-like groove of the case body and the rotary bezel is attached to be held by the case body so as not to be drawn to be detached to the upper side. After finishing the integration, when the rotary bezel receives a rotational operating force, a position of the holding member relative to the peripheral direction of the ring-like groove of the case body is changed and the rotary bezel is rotated to an arbitrary rotational position. 
   In accordance with another aspect of the invention, the holding member for preventing detachment of the rotary bezel from the case body is supported by the rotary bezel and is not arranged on an outer side of the rotary bezel. Therefore, the holding member or the like does not hamper the operation of rotating the rotary bezel. Furthermore, the ring-like groove of the case body is covered to be concealed by the rotary bezel, and the total of the outer peripheral face of the fitting portion of the rotary bezel is exposed, and therefore, the thickness of the bezel portion touched by the finger of the user in operating to rotate the rotary bezel is ensured to be large and the finger is easy to be caught thereby. 
   Further, as described above, the total of the outer peripheral face of the fitting portion of the rotary bezel is exposed, and therefore, the constitution is advantageous in designing the rotary bezel. In addition thereto, the holding member which is not arranged on the outer side of the rotary bezel does not constitute a hindrance when the rotary bezel is enlarged. Therefore, the large-diameter formation of the rotary bezel can be achieved without enlarging the case body, therefore, a restriction of the total of the timepiece in view of design is inconsiderable. 
   In the preferable mode of the invention, the ring-like groove and the guide groove respectively include guide faces opposed to each other in an up and down direction and in parallel with each other and the holding member includes upper and lower faces in parallel with each other guided by the guide faces. In the invention, the innermost faces of the ring-like groove and the guide groove over the up and down guide faces may be bent or may be constituted by a state orthogonal to the guide face. 
   In the mode of the invention, a clearance of fitting in the up and down direction between the ring-like groove and the holding member remains unchanged regardless of a degree of a depth of fitting the holding member to the ring-like groove of the case body. Therefore, even when the fitting depth is assumedly brought into a shallow state, the rotary bezel can be held such that the rotary bezel is not rattled considerably in the up and down direction. 
   In the preferable mode of the invention, the holding member includes a vertical hole or a groove penetrating a center portion of the member in the up and down direction, and a horizontal hole in a circular shape communicated with the vertical hole or the groove at a center portion in a height direction of the holding member, a front end portion of the operating screw is formed by a fitting shaft portion attached with a head slenderer than a screw shaft portion of the operating screw, and the fitting shaft portion is rotatably fitted to the horizontal hole and is prevented from being drawn from the horizontal hole by the head. 
   According to the mode of the invention, a part for preventing the holding member from being detached from the operating screw is not needed and an integration of connecting the holding member and the operating screw can be carried out by time and labor of only penetrating the fitting shaft portion attached with the head to the horizontal hole. Further, the head of the fitting shaft portion in correspondence with a part for preventing the holding member from being detached from the operating screw is contained in the vertical hole of the holding member as described above, and therefore, it is not necessary to deeply form the ring-like groove in consideration of the part. Therefore, since the ring-like groove can be made shallow, the fitting portion of the case body formed with the ring-like groove can be prevented from having a large diameter in view of maintaining a wall thickness of achieving a strength necessary therefor. 
   In a preferable mode of the invention, the guide groove is formed in a ring-like shape. 
   According to the mode of the invention, the guide groove opened to an inner periphery of the rotary bezel can simply be formed. 
   In a preferable mode of the invention, the head portion of the operating screw is projected from an outer peripheral face of the fitting portion in a state of arranging the holding member at the holding position. In the invention, it is preferable to constitute the head portion of the operating screw in a semispherical shape, further, when projected portions in a semispherical shape projected integrally from the outer peripheral face are provided at the fitting portion at intervals, and the head portion of the operating screw is disposed in the alignment of the projected portions, the finger is further easy to be caught thereby, and therefore, the constitution is preferable. 
   In the mode of the invention, the head portion of the operating screw can be utilized as a portion for catching the finger of the user when the rotary bezel is operated to rotate. 
   According to the invention, the rotary bezel can be attached and detached without being accompanied by deformation of the rotary bezel and the case body, further, in addition to the fact that the finger is easy to be caught by the rotary bezel, there is not a member of hampering the rotational operation at a surrounding of the rotary bezel, and therefore, the rotation operability of the rotary bezel can be promoted and there is not a member around the rotary bezel, and therefore, a timepiece without bringing about large-sized formation of the case body when the rotary bezel is enlarged in view of design can be provided. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plane view showing a wristwatch according to a first embodiment of the invention. 
       FIG. 2  is a cross-sectional plane view showing the wristwatch of  FIG. 1 . 
       FIG. 3  is a sectional view taken along a line Z-Z in  FIG. 1  showing a state of attaching a rotary bezel provided to the wristwatch of  FIG. 1  to be held by a case body. 
       FIG. 4  is a sectional view taken along the line Z-Z in  FIG. 1  showing a state of releasing the rotary bezel provided to the wristwatch of  FIG. 1  from being held by the case body. 
       FIG. 5  is a sectional view showing a relationship of a holding member and an operating screw provided to the wristwatch of  FIG. 1 . 
       FIG. 6  is a perspective view showing the holding member provided to the wristwatch of  FIG. 1 . 
       FIG. 7  is a sectional view in correspondence with  FIG. 3  showing a wristwatch according to a second embodiment of the invention. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   A first embodiment of the invention will be explained in reference to  FIG. 1  through  FIG. 6 . 
   In  FIG. 1 , notation  10  designates a timepiece, for example, a portable timepiece, specifically, a wristwatch. A timepiece movement  13  for driving an indicating hand  12  (refer to  FIG. 1 ), a dial  14  attached to the timepiece movement  13 , and a frame-like member  15  for holding the timepiece movement  13  at a timepiece exterior assembly  11  and the like as shown by  FIG. 3  and  FIG. 4  are contained in the timepiece exterior assembly  11  provided to the wristwatch  10 . The indicating hand  12  and the dial  14  constitute a timepiece display portion. 
   As shown by  FIG. 3  and  FIG. 4 , the timepiece exterior assembly  11  is formed by attaching a cover glass  17  as a transparent cover and a case back  18  to a case body  16  made in a ring or ring-like shape by a metal. Further, the transparent cover can also be formed of a transparent synthetic resin. A front side of the case body  16  is integrally formed with a ring-like portion  16   a  in a circular shape in a plane view thereof, and the cover glass  17  is mounted to an inner side of the ring-like portion  16   a  in a circular shape in a plane view thereof, and the cover glass  17  is mounted to an inner side of the ring-like portion  16   a  in a liquid tight manner. Therefore, the ring-like portion  16   a  is provided to surround the cover glass  17 . Further, notation  19  in  FIG. 3  and  FIG. 4  designates a waterproof packing in a ring-like shape sandwiched by the ring-like portion  16   a  and the cover glass  17 . The indicating hand  12  and the dial  14  can visually be recognized through the cover glass  17 . The case back  18  is made of a metal and screwed detachably to a back face side of the case body  16 . Further, notation  20  in  FIG. 3  and  FIG. 4  designates a waterproof packing in a ring-like shape sandwiched by the case body  16  and the case back  18 . 
   As shown by  FIG. 2  through  FIG. 4 , a ring or ring-like groove  21  is formed at the ring-like portion  16   a  of the case body  16 . The ring-like groove  21  is opened to an outer periphery of the ring-like portion  16   a . A sectional shape of the ring-like groove  21  is a channel-like shape, therefore, the ring-like groove  21  includes guide faces  21   a  and  21   b  in a horizontal shape opposed to each other in an up and down direction and in parallel with each other. 
   The case body  16  includes a shoulder portion  16   b  in a ring-like shape integral with a root of the ring-like portion  16   a  and continuously expanded to an outer side. The shoulder portion  16   b  is formed with a recess groove  22  opened from an upper face thereof. The recess groove  22  is constituted by a ring-like shape and provided concentrically with the ring-like portion  16   a.    
   Notations  16   a  and  16   d  in  FIG. 1  and  FIG. 2  designate a pair of tube feet integral with the case body  16 . One pair of the tube feet  16   c  opposed to each other in the 3 o&#39;clock-9 o&#39;clock direction are provided on the 12 o&#39;clock side. The other pair of the tube feet  16   d  opposed to each other similarly in the 3 o&#39;clock-9 o&#39;clock direction are provided on the 6 o&#39;clock side. A timepiece strap, not illustrated, is attached to the tube feet  16   c . Further, notation  23  in  FIG. 1  and  FIG. 2  designates a crown. 
   As shown by  FIG. 1 , the timepiece exterior assembly  11  includes a rotary bezel  31  in a ring or ring-like shape. The rotary bezel  31  is made of, for example, a metal and includes a fitting portion  32  and a cover portion  33  integral therewith as shown by  FIG. 3  and  FIG. 4 . The cover portion  33  can be formed separately from the fitting portion  32  to be connected to the fitting portion  32 . 
   The fitting portion  32  of the rotary bezel  31  constitutes a shape of a short cylinder having a height substantially the same as, for example, a height of the ring-like portion  16   a , and fitted to an outer periphery of the ring-like portion  16   a  attachably and detachably. An outer diameter of the fitting portion  32  is substantially the same as, for example, an outer diameter of the shoulder portion  16   b  of the case body  16 , and therefore, an outer peripheral face of the fitting portion  32  is provided to be continuous to an outer peripheral face of the shoulder portion  16   b  to be flush therewith on an upper side. 
   The cover portion  33  is folded to bend from an upper end of the fitting portion  32  to an inner side to cover an upper end face of the ring-like portion  16   a . At a corner made by the outer peripheral face of the fitting portion  32  and a surface of the cover portion  33 , as shown by  FIG. 1 , grooves  34  are formed at constant intervals along a peripheral direction of the rotary bezel  31 . The respective grooves  34  are provided to prevent the finger of a user from slipping when the rotary bezel  31  is operated to rotate. Further, the grooves  34  can also be provided so as to extend in an up and down direction over the whole thickness of the outer peripheral face of the fitting portion  32 . 
   As shown by  FIG. 1 , the surface of the cover portion  33  is provided with a display  33   a  for indicating a rotational position of a numeral, a graduation or the like. The display  33   a  can be matched to an arbitrary position related to a display of the dial  14  by operating to rotate the rotary bezel  31 . Therefore, by matching the display  33   a  to a specific indicating hand angle of, for example, competition start time, start of diving or the like, a time period elapsed from the competition start time point or a time period elapsed from the start of diving can be known. 
   Next, an explanation will be given of holding means for preventing the rotary bezel  31  from being detached from the case body  16  while permitting the rotational operation of the rotary bezel  31 . The holding means includes the ring-like groove  21 , a plurality, for example, 3 pieces of operating screws  41  and holding members  51  connected to the operating screws  41 . 
   In details, the fitting portion  32  of the rotary bezel  31  includes a guide groove  35  opened from an inner peripheral face of the fitting portion  32 . As shown by  FIG. 2 , the guide groove  35  is formed in a ring-like shape and is provided at a height the same as that of the ring-like groove  21 . Therefore, the guide groove  35  and the ring-like groove  21  are provided to communicate with each other by making openings thereof opposed to each other. 
   The guide groove  35  includes guide faces  35   a  and  35   b  in a horizontal shape opposed to each other in the up and down direction and in parallel with each other similar to the ring-like groove  21 . The constitution of making the guide groove  35  in the ring-like shape is preferable in that workability is excellent when the guide groove  35  is worked by machining at the rotary bezel  31 . 
   The fitting portion  32  is provided with recess portions  36  and screw holes  37  of numbers the same as that of the operating screws  41 . The recess portion  36  is constituted by a round hole, provided at a height the same as that of the guide groove  35  in correspondence therewith and is opened to an outer peripheral face of the fitting portion  32 . The screw hole  37  is provided with a diameter smaller than that of the recess portion  36  and communicates the guide groove  35  and the recess portion  36 . As shown by  FIG. 2 , the recess portions  36  and the screw holes  37  both ends of which are opened to center portions thereof and innermost faces of the guide groove  35  are provided at intervals of, for example, 120 degrees. 
   As shown by  FIG. 3  through  FIG. 5 , the operating screw  41  is formed by providing a head portion  43  at one end portion of a screw shaft portion  42  and providing a fitting shaft portion  44  attached with a head  44   a  constituting a front end portion of the operating screw  41  at other end portion of the screw shaft portion  42 . A total of the head portion  43  is made by a size of being able to be contained in the recess portion  36 . The fitting shaft portion  44  is formed to be slenderer than the screw shaft portion  42  and the head  44   a  constitutes a converging shape. 
   The operating screw  41  is screwed to the screw hole  37  from an outer side of the fitting portion  32  of the rotary bezel  31  and is attached movably along a diameter direction of the rotary bezel  31 . As shown by  FIG. 3 , a total of the head portion  43  is fit in the recess portion  36  in a state of screwing the operating screw  41  to butt to an innermost face of the recess portion  36 . 
   As shown by  FIG. 6 , the holding member  51  is formed of a block of a metal constituting, for example, a shape of a parallelepiped. A height dimension A of the holding member  51  is substantially equal to a dimension between the guide faces  21   a  and  21   b  of the ring-like groove  21  and a dimension between the guide faces  35   a  and  35   b  of the guide groove  35 . A width B of the holding member  51  is equal to or smaller than a depth dimension of the guide groove  35 . Therefore, a total of the holding member  51  is made by a size capable of being fit into the guide groove  35 . 
   As shown by  FIG. 5  and  FIG. 6 , the holding member  51  includes a vertical hole  52  and a horizontal hole  53 . As shown by  FIG. 3  and  FIG. 4 , the vertical hole  52  is penetrated in the up and down direction at a center portion of the holding member  51  and is made to a size capable of containing the head  44   a . The horizontal hole  53  is communicated with the vertical hole  52  at a center portion in a height direction of the holding member  51 . The horizontal hole  53  is a hole in a circular shape and a diameter thereof is larger than a portion of the fitting shaft portion  44  excluding the head  44   a  and smaller than a diameter of the head  44   a . Further, in place of the vertical hole  52 , a groove penetrated in the up and down direction can also be constituted. 
   The holding member  51  is attached to the rotary bezel  31  by the following procedure. 
   First, the operating screw  41  is screwed to the screw hole  37  of the rotary bezel  31  to project the fitting shaft portion  44  into the guide groove  35 . 
   Next, the horizontal hole  53  is fitted to the fitting shaft portion  44  while inserting the holding member  51  to the guide groove  35  by directing the horizontal hole  53  to a lower side. Thereby, the head  44   a  of the fitting shaft portion  44  is press-fit to the horizontal hole  53  while being accompanied by flexible deformation. 
   Further, at a time point of passing the head  44   a  through the horizontal hole  53  to be arranged at the inside of the vertical hole  52 , the fitting shaft portion  44  is rotatably fitted to the horizontal hole  53  and integration is carried out such that the fitting shaft portion  44  is not drawn from the horizontal hole  53  by recovering the head  44   a . In the integrated state, upper and lower faces (only upper face is shown by notation  51   a  in  FIG. 6 ) constituting a horizontal shape of the holding member  51  are slidably brought into contact with the guide faces  35   a  and  35   b  of the guide groove  35 . 
   Therefore, the rotary bezel  31  is attached to the case body  16  by the following procedure. First, by operating to rotate the operating screw  41  in a loosening direction, the holding member  51  is moved along with the operating screw  41  to slide at the guide faces  35   a  and  35   b  of the guide groove  35 , and as shown by  FIG. 3 , the holding member  51  is arranged at a position of pulling the total of the holding member  51  to fit into the guide groove  35 , that is, at a release position. 
   Next, the fitting portion  32  of the rotary bezel  31  is fitted to cover the ring-like portion  16   a  of the case body  16 . 
   Thereafter, by screwing the operating screw  41  in a fastening direction, the holding member  51  is moved along with the operating screw  41  from the release position to the ring-like portion  16   a  by constituting a guide by the guide faces  35   a  and  35   b . Thereby, as shown by  FIG. 4 , the holding member  51  is arranged at a holding position at which a portion (front end side portion) of the holding member  51  is inserted to the ring-like groove  21 , the upper face  51   a  of the holding member  51  is slidably brought into contact with the guide face  21   a  of the ring-like wall  21  and a lower face of the holding member  51  is slidably brought into contact with the guide face  21   b  of the ring-like wall  21 . 
   At the holding position, the holding member  51  is arranged over the ring-like groove  21  and the guide groove  35 . Therefore, by catching the holding member  51  by the ring-like groove  21 , the rotary bezel  31  is attached to and held by the case body  16  in a state of preventing the rotary bezel  31  from being directed to an upper side relative to the ring-like portion  16   a.    
   Further, in order to detach the rotary bezel  31  from the case body  16  in carrying out maintenance around the rotary bezel  31  or the like, the detachment may be carried out by a procedure reverse to that of integration explained above. 
   As described above, the rotary bezel  31  can be detached from the case body  16  by moving the holding member  51  to the release position by rotating the operating screw  41  attached rotatably to the rotary bezel  31 . Therefore, an excessively large external force is not exerted to the rotary bezel  31  and the case body  16 , and therefore, the rotary bezel  31  and the case body  16  are not deformed. Further, the same goes also when the rotary bezel  31  is attached to the case body  16 . 
   A number of engaging grooves  38  (only one is illustrated) are provided at a lower face of the fitting portion  32  of the rotary bezel  31  opposed to an upper face of the shoulder portion  16   b  of the case body  16 . The engaging grooves  38  are formed continuously along a peripheral direction of the fitting portion  32  and opposed to the recess groove  22 . The recess groove  22  is attached with a leaf spring  39  for urging the rotary bezel  31  in an upper direction, and the leaf spring  39  is engageably and disengageably engaged with the engaging groove  38  by its own elastic force. The leaf spring  39  is engaged with and disengaged from the engaging groove  38  in accordance with rotating the rotary bezel  31 , thereby, a click feeling is given to the operation of rotating the rotary bezel  31 . 
   Notation  45  in  FIG. 3  and  FIG. 4  designates a packing disposed between the cover portion  33  and the guide groove  35  and attached to an inner peripheral face of the fitting portion  32 . The packing  45  is formed in a ring-like shape and is made of a soft synthetic rubber or the like and is provided by bringing an inner peripheral face thereof into close contact with an outer peripheral face of the ring-like portion  16   a  at a position upward from the ring-like groove  21 . 
   Thereby, a pertinent resistance is provided to rotation of the rotary bezel  31  and wear between the outer peripheral face of the ring-like portion  16   a  and the inner peripheral face of the fitting portion  32  is prevented. Further, the leaf spring  39  and the packing  45  are parts constituting an object of maintenance. Further, by the packing  45 , a foreign matter of sand particles, dust or the like is restrained from invading the ring-like groove  21  of the holding means from the front side of the wristwatch  10 , and therefore, the rotation of the rotary bezel  31  is not hindered. 
   According to the wristwatch  10  having the above-described constitution, the holding member  51  for preventing the rotary bezel  31  from being detached from the case body  16  and the operating screw  41  for moving the holding member  51  are supported by the rotary bezel  31 . Therefore, when an operator operates to rotate the rotary bezel  31 , the operation of rotating the rotary bezel  31  is not hindered by constituting a stopper by the holding member  51  or the like. 
   Furthermore, the rotary bezel  31  covers to conceal the ring-like groove  21  of the case body  16  and a total of an outer peripheral face of the fitting portion  32  of the rotary bezel  31  is exposed. Therefore, a thickness of the bezel portion touched by the finger of a user when operating to rotate the rotary bezel  31  is ensured to be large and the finger is easy to be caught thereby. Therefore, the rotation operability of the rotary bezel  31  can be promoted. 
   When the rotary bezel  31  is operated to rotate and the position of the holding member  51  in the peripheral direction of the ring-like groove  21  is changed, the holding member  51  slides on the guide faces  21   a  and  21   b  along the peripheral direction of the ring-like groove  21 . In this case, the plurality of holding members  51  sliding on the ring-like groove  21  are arranged at equal intervals in the peripheral direction of the ring-like groove  21 , and therefore, the rotary bezel  31  is not inclined and the rotation can be stabilized. 
   As described above, the fitting portion  32  of the rotary bezel  31  covers to conceal the ring-like groove  21  of the case body  16  and the total of the outer peripheral face of the fitting portion  32  is exposed. Thereby, the rotary bezel  31  can be designed including the exposed face, and therefore, the constitution is advantageous in view of design. In addition thereto, the holding member  51  for preventing detachment of the rotary bezel  31  from the case body  16  is not arranged on an outer side of the rotary bezel  31 , and therefore, the holding member  51  does not constitute a hindrance in enlarging the rotary bezel  31 . Thereby, large-diameter formation of the rotary bezel  31  can be achieved without enlarging the case body  16 , and therefore, a restriction in view of design of a total of the wristwatch  10  is inconsiderable and a degree of freedom of design in view of design is high. 
   Further, the ring-like groove  21  of the case body  16  includes the guide faces  21   a  and  21   b  opposed to each other in the up and down direction and in parallel with each other, also the guide groove  35  includes the guide faces  35   a  and  35   b  opposed to each other in the up and down direction and in parallel with each other, and upper and lower faces of the holding member  51  are guided by the guide faces. Therefore, a clearance of fitting the ring-like groove  21  and the holding member  51  in the up and down direction remains unchanged regardless of a degree of a depth of fitting the holding member  51  to the ring-like groove  21 . Therefore, even when the fitting depth is assumedly brought into a shallow state, the rotary bezel  31  can be held such that the rotary bezel  31  is not rattled considerably in the up and down direction, and therefore, rotation of the rotary bezel  31  can be stabilized. 
   Further, the holding member  51  and the operating screw  41  are connected while preventing the fitting shaft portion  44  from being drawn from the horizontal hole  53  by the head  44   a  of the fitting shaft portion  44  by rotatably fitting the fitting shaft portion  44  attached with the head  44   a  of the operating screw  41  to the horizontal hole  53  of the holding member  51 , and therefore, a part of preventing the holding member  51  from being detached from the operating screw  41  is not needed. Along therewith, the holding member  51  and the operating screw  41  can be connected by time and labor of only penetrating the fitting shaft portion  44  to the horizontal hole  53 . Therefore, a connection operability of the holding member  51  and the operating screw  41  is excellent. 
   Further, the head  44   a  of the fitting shaft portion  44  in correspondence with a part for preventing the holding member  51  from being detached from the operating screw  41  is contained in the vertical hole  52  of the holding member  51 , and therefore, it is not necessary to deeply form the ring-like groove  21  in consideration of a thickness of the part for preventing the detachment or the like. Therefore, the ring-like portion  16   a  of the case body  16  formed with the ring-like groove  21  can be prevented from having a large diameter when the ring-like groove  21  can be made shallow in view of maintaining a wall thickness of achieving a strength necessary therefor. 
   A second embodiment of the invention will be explained in reference to  FIG. 7 . The second embodiment is the same as the first embodiment except for an item explained below, and therefore, the constitution the same as that of the first embodiment is attached with a notation the same as that of the first embodiment and an explanation thereof will be omitted. 
   According to the second embodiment, the head portion  43  of the operating screw  41  is projected from the outer peripheral face of the fitting portion  32  even in the state of arranging the holding member  51  to the holding position. Further, the head portion  43  is formed in, for example, a semispherical shape. The second embodiment is the same as the first embodiment except the item explained above. 
   Therefore, also the wristwatch  10  of the second embodiment can resolve the problem of the invention by the reason already explained in the first embodiment. Further, the head portion  43  of the operating screw  41  projected from the outer peripheral face of the fitting portion  32  can be utilized as a portion of touching the finger of the user in operating to rotate the rotary bezel  31 , and therefore, the constitution is effective in further promoting the rotation operability of the rotary bezel  31 .