Abstract:
A timepiece has a case band having a front side end part that projects inwardly toward the hollow interior of the case band and terminates in a front opening. A case back is detachably attached to a back side end part of the case band. A glass is fixed to an annular edge member that seats on a front face of the front side end part. The edge member has a tubular part slidably inserted into the front opening and threadedly engaged with an annular attaching member in the interior of the case whereby the front side end part of the case band is sandwiched and held between the edge member and attaching member. By detaching the case back and using a tool to unthread the attaching member from the edge member, the edge member and glass can be removed as a unit from the case band for repair or replacement.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a timepiece such as a portable watch like, e.g., a wristwatch and a pocket watch, a desk clock and a wall-mounted clock. 
   2. Description of the Prior Art 
   Hitherto, among wristwatches possessing a case back, there is known a wristwatch in which an annular protrusion part is formed in an inner periphery of a front side end part of a case band in which a dial is accommodated, to the inner periphery of this annular protrusion part, a glass covering the dial is fitted and fixed and a tubular part of an edge member functioning also as a bezel is fitted, and a caulking part integral with this tubular part is caulked to a back face of the annular protrusion part (for example, refer to JP-UM-B-5-37273 Gazette). 
   In the wristwatch in which the edge member has been caulked to the case band as mentioned above, since the fact that a caulked part having been deformed is caulked again after having been returned to a state before being caulked extremely decreases a mechanical strength of the caulked part, it is impossible to detach the edge member from the case band. For this reason, in a case where the edge member has been impaired, a user of the wristwatch is obliged to exchange not only the edge member to which the glass has been fixed but also the case band to which this edge member has been caulked. 
   Further, in a wristwatch in which a waterproofness has been intended by nipping a seal packing between the case band and the edge member, there is considered the fact that a performance of the seal packing decreases during a long period guarantee term of the wristwatch and thereafter. Also in a case where, in order to cope with this, it is attempted to exchange the seal packing, since it is possible to detach the edge member from the case band, it is obliged to exchange not only the edge member but also the case band to which this edge member has been caulked. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a timepiece in which it has been made possible to exchange the edge member to which the glass has been fixed, without also exchanging the case band. 
   The present invention comprises an annular case band which has a front side end part forming a fitting hole, and in which the end part has an edge receiving face around the fitting hole, and a case back detachably attached to a back side end part of the case band. An annular edge member has a tubular part capable of being inserted into and disengaged from the fitting hole and a cover part that overlaps the edge receiving face. A glass is fitted and fixed to an annular step part formed in the edge member, and an attaching member detachably attaches the tubular part to the front side end part, and is attached/detached under a state that the case back has been detached. 
   In the present invention, the edge receiving face may be provided continuously so as to bulge from a front side open end of the fitting hole to its periphery, or may be provided by forming a step between it and the front side open end such that the front side open end and the edge receiving face exist in different height positions about a thickness direction of the case band. Further, the edge receiving face and a contact face, of the cover part, contacting with the former is not limited to a plane along a direction perpendicularly intersecting with a thickness direction of the case band, and may be a slant face along a direction slantingly intersecting with the thickness direction of the case band or a curved face curving along the direction slantingly intersecting with the thickness direction of the case band. 
   In the present invention, the outer periphery of the tubular part and the fitting hole into which this tubular part is inserted may be a circular shape or a polygonal shape. In the present invention, a fixation of the glass to the annular step part of the edge member may be fixed by using an adhesive, or pressure-inserting the glass to the annular step part with a seal part having an elasticity being nipped between it and the annular step part. 
   In the present invention, the attaching member is not limited to a thread ring which will be explained in an embodiment. For example, it is also possible to use an attaching member consisting of a snap ring of a C-shaped form or the like, which is detachably attached to an annular groove having been formed in an outer periphery face of the tubular part having been formed longer than a thickness of the front side end part of the case band, and which is caught to an engaging back face of the front side end part under a state attached to this groove, thereby nipping this front side end part between it and the cover part. Or, in a case where in the front side end part of the case band there has been formed an annular locking groove opening to an inner periphery face of the case band, and in the tubular part there have been formed an annular attaching groove opening to an inner periphery of the tubular part and plural through-holes which communicate with the annular attaching groove and communicate with the annular locking groove under a state that the tubular part has been inserted into the fitting hole, it is also possible to use a C-shaped attaching member having an elasticity, which has plural catching parts inserted into the annular locking groove through the through-hole to thereby be caught and is attachable/detachable to/from the annular attaching groove. In this case, a surface side end part of the case band may protrude into an inner hollow part of the case band, or may not protrude. 
   In the present invention, a state that the cover part of the edge member has been overlapped with the edge receiving face of the case band by the fact that the tubular part of the edge member to which the glass has been fixed is inserted into the fitting hole of the case band, is held by the attaching member having been accommodated inside the case band and attached to the tubular part, and this attaching member can be attached/detached under a state that the case back has been opened. For this reason, in a case where the edge member has been impaired or the like, the edge member can be attached to and detached from the case band by attaching/detaching the attaching member. Accordingly, the edge member to which the glass has been fixed can be exchanged without accompanying the case band. 
   In a preferred mode of the present invention, there is possessed an annular seal packing having been nipped between the edge receiving face and the cover part under a compressed state. Here, the seal packing may be provided by annularly forming a holding groove in either of the edge receiving face and the cover part and fitting it to this holding groove, or also can be provided without forming such a holding groove. 
   In this preferred mode, as already mentioned, since incorporation and separation of the edge member with respect to the case band can be performed by the attachment/detachment of the attaching member, in a case where a performance of the seal packing bearing a waterproofness/dustproofness between the edge receiving face and the cover part has decreased, it is possible to exchange this packing without accompanying at least the case band between the case band and the edge member. 
   Additionally, in a preferred mode of the present invention, the front side end part has an engaging back face continuous so as to bulge around the fitting hole, the tubular part has a female thread part, and the attaching member has a male thread part meshed with the female thread part and a ring base part which is caught to the engaging back face to thereby nip the front side end part between it and the cover part. 
   In this preferred mode, rotation operation of the attaching member enables fixation of the edge member to the case band by a screwing of the edge member with respect to the tubular part, and separation of the edge member from the case band by a release of the screwing with respect to the tubular part. For this reason, attachment/detachment operation of the edge member with respect to the case band in a narrow space in the case band can be simply performed without requiring a labor for deforming the attaching member. 
   Further, in a preferred mode of the present invention, there is possessed a rotation-stop, means which whirl-stops the edge member by engaging the fitting hole and the tubular part in their peripheral direction. Here, as the rotation-stop means, there can be enumerated, e.g., a means in which outer peripheries of the fitting hole and the tubular part are made a polygonal shape, and which whirl-stops the edge member by a catching in a peripheral direction by butting (engaging) between a corner of the polygonal fitting hole and a corner of the tubular part. Other than this, there can be enumerated a means which whirl-stops the edge member by a catching in the peripheral direction by an engagement between one or more groove(s) having been provided in one of the fitting hole and the tubular part and one or more convex part(s) having been provided in the other, or the like. 
   In this preferred mode, when the attaching member is meshed and screwed to the tubular part of the edge member, since the rotation-stop means whirl-stops the edge member, the screwing of the attaching member becomes easy and the edge member can be certainly fixed. Moreover, since the edge member is positioned with respect to the case band by the whirl-stop, in a case where the edge member is an ornament ring like a bezel, it is desirable also in a point that the case band can be fixed to the edge member with an ornament site of this ring being held in a suitable position. 
   Further, in a preferred mode of the present invention, the glass is fixed to the annular step part by an adhesive. 
   In this preferred mode, since the attachment/detachment of the edge member to/from the tubular part of the edge member is performed without giving an excessive strain to the edge member, there is no fear that the glass is exfoliated with the strain of the edge member which is caused when the edge member to/from the case band is attached/detached. Moreover, in addition to the fact that a periphery face of the glass is bonded to an annular periphery face of the annular step part along a thickness direction of the edge member, since a periphery part back face of the glass is bonded to a seat face of the annular step part continuous perpendicularly to the annular periphery face, a bonding area can be largely ensured. For this reason, it is possible to thin a thickness of the edge member while ensuring a necessary bonding area with respect to the glass. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention is illustrated in the accompanying drawings in which: 
       FIG. 1  is a plan view showing a wristwatch according to a first embodiment of the present invention; 
       FIG. 2  is a sectional view showing one part of the wristwatch of  FIG. 1 , while being enlarged; 
       FIG. 3  is a perspective view showing one part of an edge member of the wristwatch of  FIG. 1 ; 
       FIG. 4A  is a perspective view showing one part of an attaching member that the wristwatch of  FIG. 1  possesses, while being seen from a front side;  FIG. 4B  is a perspective view showing one part of the attaching member that the wristwatch of  FIG. 1  possesses, while being seen from a back side; and 
       FIG. 5  is a plan view showing a wristwatch according to a second embodiment of the present invention, with its one part being cut off. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A first embodiment of the present invention is explained by referring to  FIG. 1  through  FIG. 4 . 
   In  FIG. 1 , a reference numeral  11  denotes a timepiece, e.g., a portable timepiece capable of screw-locking a crown  12 , such as a wristwatch. As shown in  FIG. 2 , the wristwatch  11  accommodates, in its timepiece armor assembly  13 , a dial  14 , a timepiece movement (not shown in the drawing), and the like. The timepiece movement may be, for example, one powered by a small battery or a mainspring, or an automatically winding one, or one corresponding to a digital timepiece which digital-displays a time instant and the like on the dial  14  by a quartz oscillation module, or one in which the one corresponding to the digial timepiece and one other than it have been used in combination, or the like. 
   The timepiece armor assembly  13  is formed by mounting a glass  27  to a front side of an annular case band  15  through an edge member  21 , and liquid-tightly mounting a case back  31  consisting of a metal or the like to a back side of the case band  15 . 
   The case band  15  consists of a metal such as stainless steel and titanium or a synthetic resin. The case band  15  has a front side end part  15   a . The front side end part  15   a  protrudes radially inwardly toward an inner hollow part of the case band  15 , and a fitting hole  16  is formed in a front side of the case band  15  and constitutes the front opening of the case band. The fitting hole  16  is circular for instance. 
   A surface of the front side end part  15   a  forms an edge receiving face  17 . This edge receiving face  17  is formed by a plane continuous perpendicularly to the fitting hole  16  so as to extend, e.g., from a front side open end of the fitting hole  16  to its periphery. A back face of the front side end part  15   a  forms an engaging back face  18 . This engaging back face  18  is formed by a plane continues perpendicularly to the fitting hole  16  so as to extend from a back side open end of the fitting hole  16  to its periphery for instance. The edge receiving face  17  and the engaging back face  18  are parallel. 
   A locking groove  19  is formed in an inner face of a back side end part  15   b  of the case band  15 . The case back  31  is detachable with respect to the case band  15  from its back side. For this reason, the case back  31  integrally has an in-case-band tubular part  32  which is elastically deformable, and engaging convex parts  32   a  (only one is shown in the drawing) are formed in several places of the tip part of the in-case-band tubular part  32 . 
   Accordingly, by inserting the in-case-band tubular part  32  into a back side opening of the case band  15 , each engaging convex part  32   a  is caught by the engaging groove  19  at the same time as the engaging convex part  32   a  climbs or slides over a lower side edge of the engaging groove  19  while accompanying an elastic deformation of the in-case-band tubular part  32 , so that it is possible to detachably mount the case back  31  to the case band  15 . Under this attached state, it is possible to detach the case back  31  from the case band  15  by inserting a tip part of a tool such as screw driver (not shown in the drawing) into a peripheral part of the case back  31  and the back side end part  15   b  to thereby detach the engaging convex part  32   a  from the engaging groove  19  by wrenching the case back  31 . Incidentally, in  FIG. 2 , a reference numeral  33  denotes an annular packing made of a resinous elastic material. The seal packing  33  is nipped under a compressed state by the case band  15  and the case back  31 , bears the waterproofness/dustproofness between them, and is fitted and attached, e.g., to a holding groove  34  provided in the case back  31 . 
   The edge member  21  is one used as, e.g., a glass edge holding the glass  27 , and is annularly formed by the metal such as stainless steel and titanium or the synthetic resin. As shown in  FIG. 2  and  FIG. 3 , the edge member  21  has integrally a tubular part  22 , a cover part  23  and an annular step part  24 . 
   The tubular part  22  has, e.g., a cylindrical shape and is configured to be inserted into and disengaged from the fitting hole  16 , and its height is shorter than a thickness of the front side end part  15   a  of the case band  15 . A female thread part  22   a  is formed in an inner periphery face of this tubular part  22 . 
   The cover part  23  overlaps the edge receiving face  17  of the front side end part  15   a . In a back face of the cover part  23 , there is formed an annular holding groove  23   a  (refer to  FIG. 3 ). To this holding groove  23   a , there is fitted an annular seal packing  25  (refer to  FIG. 2 ) made of resinous elastic material. A thickness of the seal packing  25  under its free state is larger than a depth of the holding groove  23   a.    
   As shown in  FIG. 3 , the annular step part  24  provided in an inner periphery side of the edge member  21  is formed by an annular periphery face  24   a  and a seat face  24   b . The annular periphery face  24   a  is provided along a thickness direction of the edge member  21 , and the seat face  24   b  is formed continuously, perpendicularly to the annular periphery face  24   a . It is desirable that an area of the seat face  24   b  is larger than an area of the annular periphery face  24   a . The glass  27  is fitted and fixed to this annular step part  24  through an adhesive  28  (refer to  FIG. 2 ). 
   The fixation of the glass  27  to the edge member  21  is performed by fitting the glass  27  to the annular step part  24  after the adhesive  28  has been applied to a corner part that the annular periphery face  24   a  and the seat face  24   b  form. By this, the adhesive  28  between the annular step part  24  and a periphery part of the glass  27  is extended along the annular periphery face  24   a  and the seat face  24   b , the periphery face of the glass  27  contacting with the annular periphery face  24   a  is bonded, and a periphery part back face of the glass  27  contacting with the seat face  24   b  is bonded to the edge member  21 . 
   The edge member  21  to which the glass  27  has been mounted like this is detachably attached to the case band  15  by using a ring-shaped attaching member  36 . For the attaching member  36 , there is used a thread ring shown in  FIG. 2  and  FIG. 4 . Detailedly, the attaching member  36  consists of a ring base part  37  and a meshing tube part  38  having been integrally formed in the former. 
   An outer diameter of the ring base part  37  is larger than the fitting hole  16 . As shown in  FIG. 4B , the ring base part  37  has in its back face plural operating parts  37   a . These operating parts  37   a  are formed, e.g., by a concave and provided while being spaced along a peripheral direction of the ring base part  37 . As shown in  FIG. 4A , a male thread part  38   a  is formed in an outer periphery of the meshing tube part  38 . This male thread part  38   a  is detachably meshed (threadedly engaged) with the female thread part  22   a  of the edge member  21 . 
   Attachment/detachment of the edge member  21  to/from the case band  15  is implemented inside the case band  15  as follows under a state that the case back  31  has been detached. 
   There are explained procedures for attaching the edge member  21 , to which the glass  27  and the seal packing  25  have been already incorporated, to the case band  15 . First, the tubular part  22  of the edge member  21  is fitted to the fitting hole  16  of the case band  15  from the front side of the case band  15 . Next, the attaching member  36  is accommodated into the case band  15  from a back face opening of the case band  15 , and the attaching member  36  is screwed by meshing the male thread part  38   a  of the meshing tube part  38  with the female thread part  22   a  of the tubular part  22 . In this case, the attaching member  36  is rotation-operated by using a tool which is caught to the operating parts  37   a  in at least two places. 
   In this manner, from a point of time in which the ring base part  37  of the attaching member  36  has contacted with the engaging back face  18  of the front side end part  15   a  of the case band  15 , the edge member  21  is pulled backward and displaced in a back side direction of the case band  15 . The back-side displacement ends when the cover part  23  of the edge member  21  butts against and seats on the edge receiving face  17  of the case band  15 . At the same time as this, the cover part  23  and the ring base part  37  nip the front side end part  15   a  of the case band  15 , and the seal packing  25  is nipped under a compressed state between the cover part  23  and the edge receiving face  17 , so that the edge member  21  to which the glass  27  has been fixed is liquid-tightly attached to the case band  15 . By this attachment, the glass  27  faces the dial  14 . 
   Next, there are explained procedures for detaching the edge member  21  from the case band  15 . First, a tool is inserted from the back face opening of the case band  15  under a state that the case back  31  has been detached, and this tool is caught to the operating part  37   a  that the ring base part  37  of the attaching member has. Next, the attaching member  36  is rotation-operated together with the tool in a direction unscrewing this attaching member  36 , thereby detaching the attaching member  36  from the tubular part  22  of the edge member  21 . By this, since the holding of the edge member  21  with respect to the case band  15  is released, it is possible to detach the edge member  21  by drawing out it from the case band  15 . 
   Since it is possible to attach/detach the edge member  21  to/from the case band  15  as mentioned above, in a case where the edge member  21  and the glass  27  have been impaired, it is possible to exchange the edge member  21  and the glass  27 , which are exchange objects, by detaching them from the case band  15  by the already mentioned procedures. Similarly, also in a case where a waterproof/dustproof performance of the seal packing  25  has decreased due to a long period use of the wristwatch  11 , after the edge member  21 , to which the glass  27  has been fixed, has been detached from the case band  15  by the already mentioned procedures, it is possible to exchange the seal packing  25  which is similarly the exchange object without having to exchange the edge member  21 , to which the glass  27  has been fixed, and the case band  15 . Accordingly, in each of these cases, since it becomes unnecessary to discard at least the case band  15  together with an exchange component, an exchange expense for a repair client can be reduced. 
   In the present embodiment in which the attaching member  36  has been made attachable/detachable to/from the tubular part  22  of the edge member  21  by the rotation operation of this attaching member  36  consisting of the thread ring as already mentioned, the edge member  21  can be fixed to the case band  15  by the screwing of the attaching member  36  with respect to the tubular part  22 , and the edge member  21  can be detached by releasing the fixation of this edge member  21  to the case band  15  by a release of the screwing of the attaching member  36  with respect to the tubular part  22 . For this reason, an attachment/detachment operation of the edge member  21  with respect to the case band  15  can be implemented by such a simple operation that the attaching member  36  is rotated in a narrow space within the case band  15  without requiring a labor for deforming the attaching member  36 , and thus a workability is good. 
   Moreover, the edge member  21  can be firmly mounted to the case band  15  by screwing the attaching member  36 , which has been meshed with the edge member  21 , to thereby forcibly urge the cover part  23  of the edge member  21  into engagement with the edge receiving face  17 , and a prevention/airtight performance can be made certain by forcibly compressing the seal packing  25 . Additionally, since the edge member  21  may not be detached by wrenching the edge member  21  from the front side of the case band  15 , there is no fear that the edge member  21  and the front side end part  15   a  of the case band  15  are damaged. 
   The already-mentioned attachment/detachment of the attaching member  36  to/from the tubular part  22  of the edge member  21  is performed without giving an excessive strain to the edge member  21 . By this, there is no fear that, when the edge member  21  is attached/detached to/from the case band  15 , the strain of the edge member  21  is exerted on a bonding part of the glass  27  and thus the glass  27  is exfoliated. Like this, since an action exfoliating the bonding does not work when attaching/detaching the edge member  21 , a thickness of the edge member  21  can be thinned. It is thereby possible to intend to thin the whole of the wristwatch  11 . And, even if the edge member  21  is thinned, in addition to the fact that the periphery face of the glass  27  is bonded to the annular periphery face  24   a  of the annular step part  24  along its thickness direction, since a periphery part back face of the glass  27  is bonded to the seat face  24   b  of the annular step part  24  and a bonding area of the glass  27  with respect to the edge member  21  can be largely ensured, it is possible to certainly fix the glass  27  to the edge member  21 . 
   Incidentally, in a case where the glass  27  is attached to the edge member  21  while an annular elastic packing is nipped between the periphery face of the glass  27  and the annular periphery face  24   a  of the annular step part  24  under its compressed state, the seat face  24   b  of the annular step part  24  cannot be used as a fixing face. For this reason, it is necessary to obtain a necessary glass holding force by increasing a height of the annular periphery face  24   a  and, therefore, it is obliged to thicken the edge member  21  in comparison with the present embodiment. 
   A second embodiment of the present invention is explained by referring to  FIG. 5 . Since the second embodiment is the same as the first embodiment except matters explained below, the same reference numeral is applied to the same constitution as the first embodiment and its explanation is omitted. 
   In the second embodiment, the edge member  21  functions also as an ornament ring. For this reason, e.g., in a surface of the edge member  21 , there are provided, e.g., marks  21   a  in a 90-degree interval as ornament elements, and these marks  21   a  correspond respectively to 12 o&#39;clock through 6 o&#39;clock and 9 o&#39;clock through 3 o&#39;clock on the dial  14 . Further, the wristwatch  11  of the second embodiment has a whirl-stop means of its edge member  21 . The whirl-stop means is formed by a polygonal fitting hole  16 A and a tubular part  22 A whose outer periphery is polygonal shape. A corner number of the tubular part  22 A and that of this fitting hole  16 A are the same. 
   This whirl-stop means whirl-stops the edge member  21  by the catching in the peripheral direction by butting (engaging) between the corner of the polygonal fitting hole  16 A and the corner of the polygonal tubular part  22 A. For this reason, when meshing and screwing the attaching member  36  to the tubular part  22  of the edge member  21 , by a rotation-stop means the fact can be prevented that the edge member  21  is forcedly rotated by the attaching member  36  which is rotation-operated. 
   Accordingly, at an assembly time, the screwing of the attaching member  36  can be easily performed without requiring a labor for manually stopping the rotation of the edge member  21 , and the edge member  21  can be certainly fixed to the case band  15 . By the similar reason, a separation of the attaching member  36  in disassembly work can be easily performed. 
   Moreover, as already mentioned, since there is no fact that the edge member  21  is forcedly rotated following upon the rotation operation of the attaching member  36 , the mark  21   a  that is the ornament element of the edge member  21  can be held in a position which has suitably corresponded in relation to the dial  14 . Incidentally, it is the same as the first embodiment except the matters explained above. 
   According to the present invention, it is possible to provide a timepiece in which it has been made possible to exchange the edge member without also exchanging the case band in a case where the edge member, to which the glass has been fixed, has been impaired, or the like.