JPH0972976A - Coupling structure for case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep coupling between upper and lower cases from being released accidentally. SOLUTION: A retaining protrusion 2d is formed sticking on a side wall 2b of a first case 2 and a retaining hole part 3f is formed on a side wall 3b of a second case 3 so that the retaining protrusion 2d can be retained. A regulating part 5 is provided inside the retaining hole part 3f to regulate elastic deformation of the retaining protrusion 2d inward from the side wall 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a box-shaped case connecting structure for accommodating and holding, for example, a timepiece train wheel and having an upper case and a lower case.

[0002]

2. Description of the Related Art For example, a timepiece mechanical case for accommodating and holding a timepiece train includes an upper case and a lower case made of plastic, and as shown in FIG. 4, a side wall of a first case (lower case) 10. A locking projection 12 is formed so as to project from substantially the center of a recess 11 formed on the outer peripheral surface, and a U-shaped connection is made from the side wall of the second case (upper case) 20 so that the locking projection 12 can be locked. A structure is often adopted in which the upper case 10 and the lower case 20 are connected by integrally forming the piece 21 and engaging the locking protrusion 12 with the hole 22 of the U-shaped connecting piece 21 (for example, Japanese Patent Publication 60-21815
issue). Such a coupling structure is generally called a snap fit method and is widely used for coupling cases such as a clock mechanical body and a desk electronic computer.

[0003]

In the snap-fit method, the upper case and the lower case can be easily combined without using screws, but as shown by the broken line in FIG. Locking protrusion 1 formed on the case 10
2 is easily elastically deformed toward the inside of the side wall, that is, the inside of the case due to its structure. Moreover, if the wall thicknesses of the upper case 10 and the lower case 20 are both thinned as the size of the case is reduced, the above-mentioned locking projections 12 are more easily elastically deformed toward the inside of the case. Therefore, if some external force or vibration or shock is applied to the case,
Due to the elastic deformation of the locking projections 12, the upper case 10 and the lower case 20 are easily disengaged. Upper case 10
If the lower case 20 and the lower case 20 are disconnected from each other, in the case of the timepiece mechanical body case, the timepiece train wheel mechanism including the step motor incorporated in the case becomes disjointed, which causes inconvenience. SUMMARY OF THE INVENTION It is an object of the present invention to provide a case connecting structure in which the upper case and the lower case are not inadvertently disengaged from each other even if the thickness of the case is reduced as the case becomes smaller.

[0004]

In the case connecting structure according to the present invention, a locking projection is formed on the side wall of the first case so as to project. A locking hole is formed in the side wall of the case, and a restricting portion for restricting elastic deformation of the locking protrusion inward of the side wall is provided inside the locking hole. To do.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, a watch machine body case 1 has an opening end surface (joint surface) 2a of a plastic lower case 2 and an opening end surface (joint surface) of an upper case 3 made of the same material. The surface) 3a is joined and joined by the joining portion 4. A timepiece train wheel mechanism (not shown) including a step motor is incorporated in the timepiece machine body case 1 including both cases 2 and 3. A recess 2c having a constant width is formed on the outer peripheral surface of the side wall 2b of the lower case 2 from the joining surface 2a toward the lower end surface (bottom surface). It is formed so as to integrally project toward the upper case 3. The locking surface 2e of the locking projection 2d is a flat surface, and the surface facing the joint surface 3a is a tapered guide inclined surface 2f. On the side wall 3b of the upper case 3, a U-shaped coupling piece 3c is integrally hung toward the lower case 2. The coupling piece 3c can be fitted into the recess 2c of the lower case 2 and can be engaged with the locking projection 2d of the lower case 2. The coupling piece 3c is elastically deformable outward from the side wall 3b and has two leg portions 3d, 3d that hang down in parallel with each other.
And one connecting portion 3e for connecting the lower end portions of the both leg portions
And are formed in a U shape as a whole. The locking hole 3f surrounded by the upper surface of the upper case 3, the legs 3d, 3d, and the connecting portion 3e has an opening 3g above the locking hole 3f. The locking projection 2d of the lower case 2 can be inserted into and removed from the locking hole 3f, and the connecting portion 3e is locked to the locking projection 2d during insertion. Coupling piece 3c
The inside of the lower end side is a tapered guide inclined surface 3h.
The guide surface 3h is a surface that slides on the guide inclined surface 2f of the locking projection 2d when the lower case 2 and the upper case 3 are joined. It is sufficient that at least one of the inside 3h of the lower end of the coupling piece 3c or the facing surface 2f of the engaging projection 2d and the facing surface 2f is a tapered guide inclined surface. In addition,
Slits 2g, 2g are formed on both sides of the locking projection 2d, and the locking projection 2d is connected to the coupling piece 3 by these slits.
It is more easily elastically deformed than c. Upper case 3
The locking protrusion 2d of the lower case 2 is provided inward of the locking hole 3f.
A restricting portion 5 for restricting the elastic deformation of the inside of the side wall 2b, that is, the inside of the case 1 is integrally formed to project toward the lower case 2. A surface of the restriction portion 5 facing the locking hole portion 3f is a tapered guide inclined surface 5a.

[0006]

[Description of Assembly] The coupling piece 3c of the upper case 3 is opposed to the recess 2c of the lower case 2, and the upper case 3 is inserted toward the lower case 2 (FIG. 1). The guide surface 3h of the coupling piece 3c slides on the guide surface 2f of the locking projection 2d, whereby the locking projection 2d elastically deforms inward of the side wall 2b, that is, inward of the case 1. When the upper case 3 and the lower case 2 are further brought close to each other, the head of the locking projection 2d is moved to the guide inclined surface 5 of the regulating portion 5.
It abuts on a and slides, and the locking projection 2d is sandwiched between the guide inclined surface 5a of the restriction portion 5 and the connecting portion 3e of the coupling piece 3c and advances. The locking protrusion 2d is provided on the guide inclined surface 5a of the regulating portion 5.
By sliding the head, the head receives a pressing force toward the outside of the side wall 3b, that is, toward the outside of the case 1. Due to this pressing force, the tip of the locking surface 2e of the locking projection 2d presses the connecting portion 3e of the coupling piece 3c to slightly elastically deform outward of the side wall 3b (FIG. 2). At the moment when the guide surface 3h of the coupling piece 3c crosses the guide surface 2f of the locking projection 2d, the locking projection 2d enters the locking hole 3f and engages with the coupling piece 3c, so that both cases 2 and 3 are The watch mechanical body case 1 is completed by being combined (FIG. 3). In the state shown in FIG. 3, even if some external force, vibration, shock, or the like is applied to the timepiece mechanical body case 1, the locking projection 2d of the lower case 2 is elastically deformed inward of the side wall 2b, that is, inward of the case 1. Since it is regulated by the regulation portion 5, the locking protrusion 2d does not drop out from the locking hole portion 3f, and the lower case 2 and the upper case 3 are not accidentally disengaged. In order to release the connection between the lower case 2 and the upper case 3 (in the state of FIG. 3), the engaging projection 2d is pushed inwardly of the case 1 until the head of the engaging projection 2d abuts on the restricting portion 5, and at the same time, the connecting piece 3c.
Is elastically deformed to the outside of the case 1, and the upper case 3 may be pulled up from the lower case 2 while maintaining this state. Unless such force is applied, the lower case 2 and the upper case 3 will not be disengaged. In the above-described embodiment, the locking hole portion 3f locked by the locking protrusion 2d has both legs 3d, 3d of the U-shaped coupling piece 3c hanging from the upper case 3.
The hole 3f is surrounded by the connecting portion 3e and the connecting portion 3e. However, the invention is not limited to this, and the side wall 3b of the upper case 3 may be directly provided with a hole to serve as a locking hole. . The case 1 is not limited to the watch mechanical case.

[0007]

According to the present invention, even if some external force, vibration, shock, or the like is applied to the case, the locking projection restricts the elastic deformation of the locking projection inwardly of the case. The protrusion does not fall out of the locking hole, and the lower case and upper case are not accidentally disconnected.
Therefore, the thickness of the case can be reduced to reduce the size of the case.

[Brief description of drawings]

FIG. 1 is a main part in a state where an upper case and a lower case are opposed to each other, (a) is a front view, and (b) is AA of (a).
It is a line sectional view.

FIG. 2 is a main part of a state in which the upper case and the lower case are being joined together, (a) is a front view, (b) is BB of (a).
It is a line sectional view.

3A and 3B are main parts in a state in which an upper case and a lower case are combined, FIG. 3A is a front view, and FIG. 3B is a sectional view taken along line CC of FIG.

4A and 4B are main parts for explaining a conventional case coupling structure, in which FIG. 4A is a front view and FIG. 4B is a sectional view taken along line DD of FIG.

[Explanation of symbols]

 1 Case 2 1st Case (Lower Case) 2b Side Wall 2d Locking Protrusion 3 Second Case (Upper Case) 3b Side Wall 3f Locking Hole 5 Regulator

Claims (1)

[Claims] 1. A locking projection is formed on the side wall of the first case, and a locking hole is formed on the side wall of the second case so that the locking projection can be locked. A case is characterized in that a regulating portion for regulating elastic deformation of the engaging projection inward of the side wall is provided inside the engaging hole of the second case. Construction.