Abstract:
A thin timepiece having a module stably fixed therein has a case integrated with a wrist band and a case back, the case having an opening portion on a front surface side thereof, a module having a housing formed of a resin and a timepiece movement held by the housing, the module being removable retained in the opening portion of the case, and a cover glass for covering the opening portion of the case. The housing has at least one two-sided supporting beam integrally formed in a side surface therof and being deformable in a planar direction of the housing, and a fitting projection protruding from each two-side suporting beam, and the module is fixed in the opening portion of the case by inserting the fitting projection into a corresponding engaging recess formed in an inner side face of the case.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a module fixing structure of a timepiece for integrating and fixing a module to a case having a one-piece structure integrated with a case band and a case back from an opening portion for containing the module on a side of cover glass. 
   A timepiece containing a module fixed to a case having a one-piece structure integrated with a case band and a case back; that is, a case formed with an opening portion for containing the module on a side of cover glass has an advantage in that the structure is simple and a waterproof seal may be more easily provided between the cover glass and the case. This structure is advantageous in comparison with a timepiece in which a case band and a case back are separated from each other and a module is contained and fixed to a case formed with opening portions for both of a side of a cover glass and a side of a case back. However, according to the former module fixing structure, the contained module needs to be held and fixed at a bottom face or an inner side face of the case and therefore, the former is more complicated than the latter in that respect. 
   That is, according to a module fixing structure disclosed in JP-H02-93790-U a stepped portion is formed on an upper side of an inner side wall of a case formed by resin and the stepped portion is formed with a plurality of upwardly extending projections. Meanwhile, a module is formed with a flange portion at side face thereof. When the module is integrated to the case, a lower face of the flange portion is arranged to be brought into contact with the stepped portion. Further, the projections are fixed to the flange portion by thermal caulking to thereby hold and fix the contained module at an inner side face of the case. 
   Owing to such a fixing structure, the module is stably fixed to the case. However, there poses a problem that according to such a fit-to-set fixing structure, the module cannot be removed from outside. Further, the case is formed with the stepped portion brought into contact with the lower face of the flange portion of the module and therefore, a thickness between the inner side face and an outer side face of the case is increased by an amount of the stepped portion and therefore, there poses a problem that the case becomes large-sized and cannot be adopted for a small-sized timepiece. 
   Next, there is a module fixing structure disclosed in JP-H09-189776 formed with at least two recessed portions at an inner side face of a case formed by resin. Further, the recessed portion is provided with a ceiling face. Meanwhile, a module is formed with hook portions projected outwardly from a side wall portion thereof and formed with at least two cantilever type hook portions bent to an inner diameter direction of the module. Further, the cantilever type hook portion is of a shape constituting a ceiling face engaging portion engaged with the ceiling face of the recessed portion by a portion of an upper end face of a movable end portion thereof. When the module is integrated to the case, the cantilever type hook portion is bent to the inner diameter direction by being brought into contact with the inner side face of the case, however, when the module is contained at a predetermined position, the cantilever type hook portion recovers to an original shape by elasticity in an outer diameter direction and fitted to the recessed portion of the inner side face of the case to thereby hold and fix the contained module at the inner side face of the case. 
   Owing to such a fixing structure, the module is fixed to the case. However, the module is formed with the hook portions projected outwardly from the side wall portion and formed with at least the two cantilever type hook portions bent to the inner diameter direction of the module and therefore, a thickness between the inner side face and the outer side face of the case is increased and therefore, there is a problem in that the case becomes large-sized and cannot be adopted for a small-sized timepiece. The increased thickness in this case consists of a total thickness of the hook portion and therefore, is a total of at least a thickness of an upper end portion of the movable end portion of the cantilever type hook portion and an amount of bending of the movable end portion to the inner diameter direction. 
   Meanwhile, the module fixing structure disclosed in JP-H09-189776 is not a fit-to-set fixing structure and therefore, the module can be removed from outside. That is, a portion of the upper end face of the movable end portion of the cantilever type hook portion is formed with the ceiling face engaging portion for engaging with the ceiling face of the recessed portion and formed with a hook off portion. The movable end portion of the cantilever type hook portion is bent to the inner diameter direction by inserting an engagement releasing jig from a knotched portion formed at the case and pressing the jig to the hook off portion or making the hook off portion catch the jig. Then, fitting of the cantilever type hook portion and the recessed portion is released and the module can be removed from the case to outside. 
   However, since the hook portion is the cantilever type hook portion, when the movable end portion is repeatedly bent, the hook portion cannot be recovered to the original shape by reducing the elasticity by plastic deformation and there poses a problem that the module cannot firmly be fixed to the case by fitting. Therefore, there poses a problem that it is difficult to stably fix the module to the case, detachment of the fitting is brought about when a product is dropped, or the module is inclined after having been integrated. Further, since the portion of the upper end face of the movable end portion of the cantilever type hook portion is formed with the ceiling face engaging portion for engaging with the ceiling face of the recessed portion and formed with the hook off portion, a housing of the module is constituted by a considerably complicated shape and therefore, there also poses a problem that the cost of a die for fabricating the housing by resin molding becomes necessarily increased. 
   A problem to be resolved by the invention is to provide a module fixing structure for stably fixing a module to a case having a one-piece structure and making a thickness between an inner side face and an outer side face of the case thinner than that of a conventional timepiece of this type. 
   SUMMARY OF THE INVENTION 
   In order to resolve the above-described problem, in a timepiece comprising a case integrated with a case band and a case back and having an opening portion for containing a module on a surface side, a module having a housing made of a resin and contained in the case and cover glass for covering the opening portion of the case, the module is fixed to the case by fitting the fitting projected portions formed at portions of elastically deformed portions in a shape of a two ends supporting beam integrally formed at a side face of the housing and deformed in a planar direction to a plurality of engaging recessed portions formed at an inner side face of the case. 
   Fitting of the fitting projected portions and its corresponding engaging recessed portions is carried out at at least three locations spaced apart from each other by predetermined intervals so that housing does not incline inside the case. Or, fitting of the fitting projected portions and its corresponding engaging recessed portions achieves an inclination preventing operation of the housing and carried out at at least two locations opposed to each other. 
   The fitting projected portion is a projection in a tapered shape spreading to a side of the cover glass and the module is made to be smoothly integrated to the case from an only opening portion. 
   Fitting projected portion is formed in a shape of an inverse cone and only an apex of a circular arc is brought into contact with the inner side face of the case when integrated. Therefore, an elastically deformed portion of the housing in containing a movement is smoothly deformed and a performance of integrating the movement to the case is promoted. 
   Further, a module removing recessed portion is provided at a face of the fitting projected portion on a side of the cover glass. The module is made to be able to remove from the case by deforming the elastically deformed portion of the housing to an inner diameter direction by pressing a fitting releasing jig to the recessed portion from outside of the case. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the invention will now be described with reference to the accompanying drawings wherein: 
       FIG. 1  is a disassembled perspective view of a timepiece according to an embodiment of the invention; 
       FIG. 2  is a plane view of the timepiece according to the embodiment of the invention; 
       FIG. 3  is a sectional view of the timepiece according to the embodiment of the invention; and 
       FIG. 4  is a partial sectional view cut by a line X—X of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   According to a timepiece in one embodiment of the present invention, as shown by a disassembled view in  FIG. 1 , a module  20  is fixed to a case  10  by fitting the fitting projected portions  23   b  formed at a side face of a housing made of a resin constituting a portion of the module  20  to a plurality of engaging recessed portions  11   b  formed at an inner side face  11  of the case  10  having one-piece structure integrated with a case band and a case back. The housing is preferably made of resin and comprises a first housing  23  and a second housing  24  for containing or attaching constituent parts of the module  20 . In  FIG. 1 , the fitting projected portions are provided at a portion of an elastically deformed portion  23   a  in a shape of a two-sided supporting beam formed integrally with the first housing  23  and being deformable in a planar direction. 
   That is, as shown by the disassembled view in  FIG. 1 , and in a plane view in  FIG. 2 , a sectional view cut in a strap length direction in  FIG. 3  and a partial sectional view in  FIG. 4 , respectively, the timepiece according to the presently described embodiment of the invention is constructed with the case  10  integrated with the case band and the case back and having an only opening portion  11   c  on a surface side, the module  20  having the first housing  23  made of resin and contained in the case  10  and cover glass  12  for covering the opening portion  11   c  of the case. 
   Since the case  10  is the case having the one-piece structure integrated with the case band and the case back, a containing portion thereof for containing and fixing the module  20  is a one-bag-like containing portion. According to the timepiece of the embodiment of the invention, the one-bag-like containing portion is a cylindrical containing portion having the substantially rectangular opening portion  11   c  with four corners thereof in a circular arc shape. A plurality of the engaging recessed portions  11   b  are formed at an inner side face of the one-bag-like containing portion, that is, the inner side face  11  of the case  10 . According to the timepiece of the embodiment of the invention, the plurality of engaging recessed portion  11   b  are formed by four pieces respectively at the four corners of the inner side face  11  of the case  10 . 
   According to the timepiece of the embodiment of the invention, the module  20  is constituted by a circuit block  21 , a liquid crystal display element  22 , the first housing  23  and the second housing  24 . The circuit block  21  is constituted by mounting various electronic parts constituting an electronic timepiece on a circuit board. The circuit block  21  held between a lower face of the first housing  23  and an upper face of the second housing  24  made of resin and the liquid crystal display element  22  electrically connected to the circuit block  21  is held on an upper face of the first housing  23 . A planar shape of the module  20  successively laminated and integrated with the liquid crystal display element  22 , the first housing  23 , the circuit block  21  and the second housing constitutes the substantially rectangular module with the four corners in the circular arc shape. 
   The side face of the first housing  23  is provided with a plurality of the elastically deformable portions  23   a  in the shape of the two-sided supporting beam deformable in the planar direction. In the timepiece of the presently described embodiment of the invention, four of the elastically deformable portions  23   a  of the two-sided supporting beam are provided and are integrally formed with the housing by providing through holes  23   c  in a crescent shape at each of the four corners of the first housing  23 . 
   The fitting projected portion  23   b  is formed at a portion of the elastically deformable portion  23   a  of the two-sided supporting beam. The fitting projected portion  23   b  is a projection in a tapered shape or a projection in a shape of an inverse cone spreading or opening in the direction of a side of the cover glass  12 , that is, the side of the opening portion  11   c . By having such a shape, when the module  20  is integrated to the containing portion of the case  10 , only an apex of a circular arc of the fitting projected portion  23   b  is brought into contact with the inner side face  11  of the case  10  and therefore, when the module is contained, the elastically deformed portion  23   a  is smoothly deformed and integrating performance is promoted. 
   A face of the fitting projected portion  23   b  on a side of the cover glass  12  is provided with a removing recess  23   b . There is a case of removing the module  20  temporarily contained in the case  10  from the case  10  depending on a situation of fabricating steps. At that occasion, the elastically deformed portion  23   a  in the shape of the two ends supporting beam is planarly deformed by touching a front end of an engagement releasing jig of a tweezers or the like to the removing recess  23   ba  to thereby release the fitting between the fitting projected portion  23   b  and the engaging recessed portion  11   b.    
   A procedure of containing and stably fixing the module  20  to the case  10  will be explained as follows. According to the embodiment of the invention, the module  20  is constituted by holding the circuit block  21  shown by the disassembled view in  FIG. 1  between the first housing  23  and the second housing  24  made of resin and integrating the liquid crystal display element  22  to the circuit block  21 . 
   When the module  20  is moved down to integrate the module  20  constituted in this way from the side of the cover glass  12  into the case  10 , the highest position of the inner side face  11  of the case and the fitting projected portion  23   b  provided at the first housing  23  made of resin are brought into contact with each other. When a pressing force is further exerted on the module  20 , the fitting projected portion  23   b  in the tapered shape spreading toward the outside of the cover glass  12  has a planar force planarly directed imposed thereon toward the center of the case to thereby planarly deform the elastically deformed portion  23   a  of the two-sided supporting beam formed at the first housing made of resin. Then an amount of protrusion of the fitting projected portion  23   b  formed at the portion of the elastically deformed portion  23   a  in the shape of the two-sided supporting beam from an outer periphery of the module  20  is reduced. 
   By continuing to press further, the module  20  sinks to a side opposed to the cover glass  12  and, at the same time, the fitting projected portion  23   b  moves toward the center of the case  10 . When an outermost periphery of the fitting projected portion  23   b  coincides with the inner side face  11  of the case  10 , planar deformation of the elastically deformed portion  23   a  of the two-sided supporting beam is stopped and the first housing  23  is moved along the inner side face  11  of the case. 
   When a predetermined sectional moving amount is reached, the fitting projected portion  23   b  reaches the engaging recessed portion  11   b  provided at the inner side face  11  of the case, the elastically deformed portion  23   a  returns to the original shape by the elasticity and also the fitting projected portion  23   b  is settled to a position on an outer side of the outer periphery of the module  20 . 
   As described above, when the module  20  is integrated to the containing portion of the case  10 , the elastically deformed portion  23   a  in the shape of the two-sided supporting beam is planarly deformed in the direction of the center of the case  10  since the fitting projected portion  23   b  is pressed by the inner side face  11  of the case  10 . Since the elastically deformed portion  23   a  has the two-sided supporting beam, a deformation amount thereof can be made larger than that of the conventional fitting projection having the cantilever structure. This means that a fitting amount when elastic deformation is released and the fitting projected portion and the engaging recessed portion are fitted to each other is increased. 
   Therefore, when the module  20  is integrated to the containing portion of the case  10 , it is extremely easy to deform the elastically deformed portion  23   a  such that an outer peripheral face of the module  20  and the apex of the fitting projected portion  23   b  coincides with each other. Further, when the elastically deformed portion  23   a  in the shape of the two-sided supporting beam formed in this way returns to the original shape when the fitting projected portion  23   b  is fitted to the engaging recessed portion  11   b . Thereby, the module  20  is contained and stably fixed to the containing portion of the case  10  having the one-piece structure integrated with the case band and the case back. 
   Meanwhile, as is apparent from the plane view of  FIG. 2 , according to the invention, the module  20  is stably fixed to the case  10  having the one-piece structure and the thickness between the inner side face and the outer side face of the case  10  is thinner than that of the conventional timepiece of this type. This is because the module fixing structure according to the invention is constituted by the plurality of engaging recessed portions  11   b  formed at the inner side face  11  of the case  10  and the fitting projected portions formed at the outer periphery of the housing  23  made of resin of the module  20  which are the fitting projected portions  23   b  formed at portions of the elastically deformed portions  23   a  in the shape of the two-sided supporting beam formed integrally with the outer periphery of the housing  23  made of resin. In this way, the amount of projection from the housing made of resin to the outer periphery is constituted only by the amount that the fitting projection  23   b  projects so as to be fitted to the engaging recessed portion  11   b  provided at the inner side face of the case  10 . Therefore, special means for concealing a total of the hook portion constituting the fitting portion, for example, concealing the outer periphery of the module by a dial or a bezel which has been needed in the conventional timepiece of this kind, is dispensed with. Incidentally, according to the plane view of  FIG. 2 , the concealment of the fitting portion is realized by making an outer peripheral face of a display face  12   a  of the cover glass  12  opaque, however, the opaque portion is much smaller than that in the conventional timepiece. In this way, according to the invention, the module  20  can be contained and stably fixed to the containing portion of the case  10  without covering the outer periphery of the module  20 . 
   Further, in  FIG. 1  and  FIG. 2 , there is provided the module fixing structure having four sets of portions of fitting the engaging recessed portion  11   b  and the fitting projected portions  23   b , however, a module fixing structure having three sets of the fitting positions can be constituted. Further, the module fixing structure can also be realized by two sets of the fitting portions by constituting a structure in which the module  20  is not inclined to the case  10 . The module fixing structure achieving the inclination preventing operation is a structure in which, for example, two sets of the portions of fitting the engaging recessed portions  11   b  and the fitting projected portions  23   b  are provided at positions symmetrical with each other relative to a center point of the case and a fitting area thereof is extended in a circumferential direction. 
   Further, the module  20  includes not only an electronic timepiece module having a liquid crystal display element but also a movement of a mechanical timepiece or an electromechanical timepiece. 
   The invention can provide a module fixing structure which is a module fixing structure for solidly and stably fixing a module to a case in a timepiece integrating and fixing the module from an opening portion for containing the module on a side of cover glass in the case having a one-piece structure integrated with a case band and a case back and a module fixing structure making a thickness between an inner side face and an outer side face of the case considerably thinner than that of the conventional timepiece of this type. Therefore, in the case of a timepiece having a display face the same as that of a conventional timepiece of this type, small-sized formation of the case and small-sized formation of the timepiece can be realized. Further, in the case of a timepiece having a case of a size the same as that of a conventional timepiece of this type, large-sized formation of a display face can be realized. 
   According to a module fixing structure of the invention, a module is fixed to a case by fitting the fitting projected portions formed at portions of elastically deformed portions in a shape of a two ends supporting beam integrally formed at a side face of the housing made of resin for holding the module and deformed in a planar direction to a plurality of engaging recessed portions formed at an inner side face of the case having a one-piece structure integrated with a case band and a case back. Therefore, fabrication cost of the housing is considerably reduced in comparison with that of a conventional module fixing structure having an elastically deformed portion in a cantilever shape of this type. 
   Further, since the elastically deformed portion formed with the fitting projected portion at a portion thereof is an elastically deformed portion in a shape of a two ends supporting beam type deformed in a planar direction, in comparison with an elastically deformed portion in the cantilever shape adopted in a conventional module fixing structure of this type, a stable fitting projected portion which is difficult to the deformed plastically can be realized. Further, an amount of deforming the elastically deformed portion becomes larger than that of the elastically deformed portion in the cantilever shape adopted in the conventional module fixing structure of this type and therefore, integration or removal of the module is carried out more smoothly.