Patent Abstract:
To provide a wrist watch having a small rim width while ensuring the strength of a glass rim. A movement with hands and a dial plate is assembled into a barrel from a side of a glass rim. A water-proof packing is arranged between a glass rim and the barrel. Machine screws are mounted inside the water-proof packing to fix the barrel and the glass rim together.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a wrist watch having a glass rim.  
           [0003]    2. Description of the Prior Art  
           [0004]    With conventional wrist watches, it has been general in wrist watches, in which a movement is inserted or taken out on a side of a glass rim, to fix the glass rim by means of machine screws.  
           [0005]    [0005]FIG. 3 is a view illustrating a construction of a conventional wrist watch, in which a glass rim is fixed by means of machine screws. In the construction of a conventional wrist watch, a female thread portion  21   a  is provided on an outer periphery of a water-proof packing  40  interposed between a glass rim  21  and a barrel  31 . Accordingly, a configurational dimension from a dial-plate parting diameter D 1  an outward form of to the glass rim  21  is the sum of a dial plate bearing surface width A, a width D of a wall, to which the water-proof packing  40  is mounted, a width B of a box for the water-proof packing  40 , a wall thickness C of the box, a dimension E of the female thread portion, and a width F of bearing surfaces of the glass rim  21  and the barrel  31 , that is, (A+D+B+C+E).  
           [0006]    [0006]FIG. 6 is a cross sectional view showing a construction for fixation of a chamfer-type glass rim in a conventional wrist watch. A glass rim  22  has a chamfer portion  22   a  with an interference between it and a barrel  32 , and is fixed to the barrel  32  by the interference. Accordingly, stress at the time of mounting is applied to fixed portions of the glass rim  22  and a glass  70  to make the same susceptible of deformation, so that the adhesive structure of the glass  70  to the glass rim  22  cannot be used due to deterioration in adhesive quality and so the glass  70  is fixed to the glass rim  22  through a plastic packing  70   a  having a chamfer. Also, since the glass rim  22  and the barrel  32  are fixed to each other by means of the chamfer portion  22   a , they are restricted to a round configuration in plan, and are used under such design restrictions that in view of maintenance of the quality of fixing of the glass rim  22 , the glass rim  22  is formed from a material except a precious metal or increased as a whole in wall thickness.  
           [0007]    Conventional wrist watches causes a problem that since machine screws are arranged on an outer periphery of a water-proof packing in order to maintain water-proofness for a barrel of a watch casing and a glass rim, a width from an external shape of a glass portion of the glass rim to an external shape of the glass rim is enlarged, and so it is difficult to make the glass rim thin. Therefore, although a design quality is demanded, it has been difficult under considerable design restrictions to seek after a design.  
           [0008]    Also, wrist watches, in which a glass rim is fixed by mounting a portion of the glass rim directly to a barrel of a watch casing with a chamfer, cause a problem that in order to maintain the quality of opening and closing the glass rim, the glass rim is required to have a width and thickness for ensuring the strength of a glass rim material. Further, with wristwatches intended for accessories and ornaments, a precious metal material is frequently used to make a glass rim but a usable material is limited due to the material strength and dimensional restrictions, thus causing a problem that a material is restricted. Therefore, for preservation of strength, the glass rim must be made considerable in thickness and width, so that it is not possible to make the glass rim thin and to make a thin-type wrist watch, which is wanted by users, and development of design quality is sought after with difficulty.  
           [0009]    Under these circumstances, with a chamfer-type glass rim, stress at the time of mounting possibly leads to coming-off of an adhesive portion in quality in the case where a glass is fixed to the glass rim by an adhesive, so that such way of fixation is less implemented and is made little use of. Also, at the time of maintenance of a movement with hands and a dial plate, opening and closing of the glass rim entails degradation in quality of mounting, and so the way of fixation is not accepted in the market.  
         SUMMARY OF THE INVENTION  
         [0010]    Thereupon, the invention has been devised in view of the above, and has its object to provide a wrist watch, in which a glass rim is reduced in width and in thickness, restrictions on materials for the glass rim are relaxed, and a glass rim of a high design quality having a demand in the market is fixed.  
           [0011]    The invention provides a wrist watch comprising a glass rim for fixation of a glass; a barrel, which contacts with an underside of the glass rim to contain therein a movement; a first packing provided between the glass rim and the barrel to ensure water-proofness between the glass rim and the barrel; and screws disposed inside of the packing to fix the barrel and the glass rim together.  
           [0012]    The screws are disposed inside of the first packing-whereby it is possible to provide a glass rim of a small diameter while ensuring water-proofness.  
           [0013]    Also, according to the invention, the screws have a second packing in an optional position on an external shape thereof.  
           [0014]    The second packing is provided on the screws to enable providing a glass rim of a small diameter.  
           [0015]    Also, with the wrist watch according to the invention, the barrel has screw recesses, into which the screws are inserted, and the second packings and the screw recesses engage with each other.  
           [0016]    The screw hole and the second packing engage with each other to thereby enable ensuring water-proofness on the screw hole.  
           [0017]    Further, with the wrist watch, the glass rim comprises a dial-plate bearing surface, which bears a dial-plate, a female thread portion adapted to engage with the screws, a packing box, which bears the first packing, and a bearing surface, which bears the barrel.  
           [0018]    Thereby, it is possible to reduce a width of the glass rim.  
           [0019]    Also, in the construction composed of a glass rim, a barrel and a back cover, the screws not only latch the glass rim but also may be used for fixation of the back cover as well as latching of the glass rim. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0020]    A preferred form of the present invention is illustrated in the accompanying drawings in which:  
         [0021]    [0021]FIG. 1 is a cross sectional view showing a wrist watch according to an embodiment of the invention;  
         [0022]    [0022]FIG. 2 is a side view showing a machine screw for fixation of a glass rim in a wrist watch according to an embodiment of the invention;  
         [0023]    [0023]FIG. 3 is a view illustrating a conventional construction for mounting of a glass rim;  
         [0024]    [0024]FIG. 4 is a view illustrating the construction for mounting of a glass rim according to an embodiment of the invention;  
         [0025]    [0025]FIG. 5 is a cross sectional view showing another example of a construction, in which a glass rim is mounted, according to an embodiment of the invention; and  
         [0026]    [0026]FIG. 6 is a cross sectional view showing another example of a construction for mounting of a glass rim in a conventional configuration. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    The invention will be described below in detail with reference to the drawings. In addition, the invention is not limited to embodiments.  
         [0028]    [0028]FIG. 1 is a cross sectional view showing a wrist watch as assembled according to an embodiment of the invention. A movement  10  with hands and a dial plate is assembled into a barrel  30  from a side of a glass rim  20  with a movement holding member such as an inner frame  15 , and a packing  40  intended for water-proofness between the glass rim  20  and the barrel  30  is wound around a wall of an outer periphery of a female thread portion  21   a  provided on the glass rim  20  to engage with a packing box of the barrel  30  and machine screws  50  cause the packing  40  to be engaged by the female thread portion  21   a , which is provided on the glass rim  20 , from a back side of the barrel  30  with the barrel  30  therebetween to be fixed.  
         [0029]    [0029]FIG. 2 is a side view showing a machine screw  50  for fixation of the glass rim  20 . The male screw  50  has a packing  50   a  adapted to engage in an optional position between a male screw recess  30   a  provided in the barrel  30  and the male screw, the packing having an interference for water-proofness.  
         [0030]    Hereafter, the construction of fixing the glass rim  20  in such a wrist watch will be described in order.  
         [0031]    [0031]FIG. 4 is a view illustrating the construction of a wrist watch according to the invention. The view is a cross sectional view representing the constitution from a dial-plate parting diameter D 1  to an external shape of the glass rim  20 . A configurational dimension from a dial-plate parting diameter D 1  to the glass rim  20  is (A+E+B+F), wherein a dial-plate bearing surface width is A, a dimension of the female thread portion is E, a width of a box for the water-proof packing  40  is B, and a width of bearing surfaces of the glass rim  20  and the barrel  30 .  
         [0032]    Accordingly, unlike a conventional wrist watch, the sum of a width D of a wall, to which the water-proof packing  40  is mounted, and a thickness C of a wall constituting a configuration of the box, that is, (D+C) is not necessary, so that it is possible to reduce an edge width of the glass rim  20  by (D+C). Generally, the width D of a wall, to which the water-proof packing  40  is mounted, can be reduced by from around 0.5 mm to 0.6 mm, and the thickness C of a wall constituting a configuration of the box can be reduced by from around 0.3 mm to 0.6 mm. Accordingly, (D+C) is decreased by from around 0.8 mm to 1.1 mm on one side. The entire external shape can be decreased by 1.6 mm to 2.2 mm, a value, which is twice the above value, on both sides.  
         [0033]    [0033]FIG. 5 is a cross sectional view showing another example 1 of a construction, in which a glass rim is mounted, according to an embodiment of the invention. A glass rim  20  of a wrist watch according to the another example 1 is fixed by fixing a movement  10  with hands and a dial plate into a barrel  30  through an inner frame  15  from a direction, in which the glass rim  20  is assembled into the barrel  30 , assembling the glass rim in a state, in which a water-proof packing  40  is wound around an outer wall of a female thread portion  21   a  of the glass rim  20 , and turning machine screws  50  provided with a packing  50   a  and intended for maintaining water-proofness between the screw and a male screw recess  30   a , through a back cover  60  provided for easiness of maintenance and an increase in variations of external appearance and arranged on a back surface side of the barrel  30 .  
         [0034]    Also, water-proofness between the barrel  30  and the back cover  60  is maintained by a water-proof packing disposed inside of the machine screws  50  provided with the packing and assembled on a side of the barrel  30 .  
         [0035]    As described above, since it is possible in a wrist watch of the invention to readily reduce a width of a glass rim as compared with a conventional construction, it is possible to enlarge a display portion of a dial plate by such reduction and to improve visibility of the display portion. Also, since the glass rim is fixed by machine screws, it is possible to use a material of relatively low strength such as precious metals for the glass rim. Since there is no configurational restriction in terms of construction as exemplified by circular and varied configurations in plan, there can be obtained an effect that wrist watches of different designs suited to a user&#39;s taste can be readily presented by gathering designs for the glass rim in abundance.

Technology Classification (CPC): 6