JPH0429037B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a wristwatch case.

In recent years, watch cases have been made of synthetic resin to reduce costs, reduce weight, and diversify designs. Furthermore, since synthetic resin materials can be easily colored, multicolored wristwatch cases are also manufactured by joining together a plurality of synthetic resin members each colored in a different color. However, when a watch case is manufactured by joining multiple parts together, if the joining surfaces of the multiple parts extend inside and outside the watch case, moisture may enter the watch case from the outside through the joining surfaces. ,
It had poor waterproof properties.

In addition, it is also possible to divide the joining surfaces of multiple parts so that they do not extend inside and outside the case, and then join them together, but with this configuration, only part of the outer surface of the watch case is used as the body. It was not possible to do so, and was subject to design constraints.

The present invention has been made in view of the above circumstances, and is a method for manufacturing a wristwatch case in which a body made of synthetic resin and a glass edge are joined together via a bonding surface that spans the inside and outside of the case. To provide a method for manufacturing a wristwatch case that not only can be combined but also has excellent waterproofness.

Embodiments of the present invention illustrated in the drawings will be described below.

1 and 2 show a wristwatch case for an electronic wristwatch manufactured by the wristwatch case manufacturing method of the present invention. In the figure, 1 is a case body. This case body 1 is made of a black colored synthetic resin material, and has a substantially rectangular planar shape, and has band connecting parts 2, 2 on both sides for connecting a watch band. It has been formed. A frame-shaped glass edge 3 made of a white colored synthetic resin material is integrally attached around the front part (upper part in the figure) of the case body 1, and a gasket is attached to the front opening of the glass edge 3. Glass 5 is fitted through 4. Also case body 1
A back cover 7 is removably fitted into the open back part of the watch via an O-ring 6, and a metal plate 8 is provided on the inner circumference of the case body 1 for shielding the inside of the watch case.
are integrally provided around the entire circumference.

As shown in FIGS. 3a and 3b, the glass edge 3 has a substantially rectangular frame shape in plan view, and a flange 3b for supporting a gasket 4 and a glass 5 is formed around an opening 3a in the center. In addition, the lower part of the glass edge 3 is textured on the joint surface with the case body 1, and a protrusion 3c that protrudes into the case body 1 is formed around the entire circumference, and the lower part of the flange 3b is Leg portions 3d are provided at the four corners.

In addition, on the joint surface of the case body 1 with the glass edge 3, an engaging recess 1 is provided around the entire circumference, as shown in FIG.
a is provided, the glass edge 3 and the case body 1
In the state in which they are joined, the protrusion 3c of the glass edge 3 and the engagement recess 1a of the case body 1 are engaged.

Therefore, when the glass edge 3 and the case body 1 are joined, the bonding surface between the glass edge 3 and the case body 1 extends from the inside and outside of the watch case, and this bonding surface extends from the outer surface of the watch case to the protrusion 3c. The joint surface is horizontal and goes around to the case body 1 at the protrusion 3c, and then goes upward to reach the inside of the wristwatch case. Therefore, even if moisture enters the joint between the glass edge 3 and the case body 1 from the outside, it will be blocked by the protrusion 3c and will never enter the inside of the wristwatch case. Further, the protrusion 3c and the engaging recess 1a can be formed integrally with the glass edge 3 and the case body 1, making it possible to take advantage of the characteristics of the synthetic resin wristwatch case, which are easy to manufacture and low cost.

Next, the process of manufacturing a wristwatch case having such a structure will be described with reference to FIGS. 4a, b, and c. First, the glass edge 3 is molded from white colored synthetic resin using a mold (FIG. 4a). Next, in the mold used for molding the case body 1, the glass edge 3 is set inside the upper mold 11, and the lower mold 12 is set.
The metal plate 8 provided inside the case body 1 is set inside the case body 1, and the upper mold 11 and the lower mold 12 are assembled (FIG. 4b). Then, melted black colored synthetic resin is poured into the space inside both molds 11 and 12, and after the resin has solidified, the upper mold 11 and the lower mold 12 are separated and removed. A case body 1 made of synthetic resin is molded (FIG. 4c).

Therefore, in this manufacturing process, the glass edge 3 is integrally attached when the case body 1 is molded, so that the attachment work is easy. In addition, since the lower part of the glass edge 3 is textured on the joint surface with the case body 1, it is possible to improve the adhesion with the molten synthetic resin. Since the resin is provided around the foot portion 3d, the glass edge 3 and the case body 1 can be firmly connected. Furthermore, if the protrusion 3c provided at the lower part of the glass edge 3 is made thin, the outer surface of the protrusion 3c will be melted by the molten synthetic resin, so that the bonding force between the protrusion 3c and the engagement recess 1a of the case body 1 will be reduced. This increases the waterproofness and provides more reliable waterproofness.

Note that a plurality of protrusions 3c, such as two or three, can be provided along the inner and outer directions of the wristwatch case.

Further, in the above embodiment, the protrusion 3c is provided on the glass edge 3.
Although the case body 1 is provided with an engagement recess 1a, it goes without saying that the case body 1 may be provided with a protrusion and the glass edge 3 may be provided with an engagement recess.

Further, in the above embodiment, the case is described in which the watch case is divided into the glass edge 3 and the case body 1, and the glass edge 3 and the case body 1 are joined together. The watch case may be constructed by dividing the watch into annular members and joining these three members. Furthermore, the shape and configuration of the wristwatch case are not limited to the examples, such as the shape of the wristwatch case being not limited to the rectangular shape but may be round.

As explained above, the method for manufacturing a wristwatch case of the present invention involves applying a texture to the joining surface of one of the primary molded parts of the body made of synthetic resin and the glass rim, and applying texture to the joining surface extending inside and outside the case. An annular protrusion that is sufficiently small and projects toward the tip and a plurality of feet that protrude higher than this protrusion are formed, and when molding the other member, they are primarily formed in the mold. One member is inserted, and during molding, the resin is wrapped around the multiple legs, and the textured surface and the outer surface of the protrusion are melted and fused to the other member, so that the other member is integrated. When the parts are molded, the resin wraps around the multiple legs of one of the primary molded parts to ensure firm fixation, and the textured surface of the joint surface and the surface of the annular protrusion are melted and bonded to the joint surface of the other part. Since they are fused together, it is possible to manufacture a watch case that increases bonding strength and provides reliable waterproofness.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of a wristwatch case manufactured by the method of manufacturing a wristwatch case of the present invention, and FIG. 2 is an enlarged sectional view thereof.
Figures 3a and 3b are plan views and partially cutaway sectional views of the glass rim, and Figures 4a, b, and c are explanatory diagrams showing the manufacturing process of the wristwatch case. 1...Case body, 1a...Engagement recess, 2...
Band connection part, 3...Glass edge, 3c...Protrusion, 5...Glass, 7...Back cover, 8...Metal plate,
11, 12... Mold.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a wristwatch case in which a body made of synthetic resin and a glass rim are joined together at joint surfaces extending inside and outside the case, comprising: one member of the body and glass rim. After molding, this molded one member is inserted into a mold when molding the other member, and resin is injected into the mold and the other member is molded. an annular protrusion that is joined to the other member, the joint surface of the one member is textured, and is sufficiently small with respect to the joint surface extending inside and outside the case and protrudes so as to become thinner toward the tip; A plurality of legs are formed that protrude higher than the protrusion, and when molding the other member, resin is passed around the plurality of legs of the one member, and a textured surface of the joint surface of the one member and a textured surface of the joint surface of the one member are formed. A method for manufacturing a wristwatch case, in which the one member and the other member are integrated by melting the outer surface of the protrusion and fusing it to the joint surface of the other member.