US3686882A - Watertight watch cases for wrist watches - Google Patents

Abstract

In a waterproof watch case, a plastic, outer case-body encloses a ring-shaped inner case-body. The plastic case-body acts as a shock absorber and can be colored to enhance the appearance of the watch.

Description

United States Patent Fujimori [54] WATERTIGHT WATCH CASES FOR WRIST WATCHES [72] Inventor: Xqshiaki Fujimori,Suwa, J apan [73] Assignee: Kabushiki Kaisha Svwai Suikasha,

[22] Filed: March 12, 1970 [211 App]. N0.: 18,990

[52] US. Cl. ..58/90 R, 58/91 [51] Int. Cl. ..G04b 37/08 [58] Field of Search ..58/88 R, 88 G, 88 W, 90 R,

[56] References Cited UNITED STATES PATENTS 2,765,614 10/1956 Steirnann ..58/90 R Aug. 29, 1972 2,586,086 2/1952 Pretre ..5 8/88 G FOREIGN PATENTS OR APPLICATIONS 219,449 2/ 1942 Switzerland ..58/90 R 310,872 11/1955 Switzerland 58/88 W Primary Examiner-Richard B. Wilkinson Assistant Examiner-George H. Miller, Jr. AttorneyBlum, Moscovitz, Friedman & Kaplan [57] ABSTRACT In a waterproof watch case, a plastic, outer case-body encloses a ring-shaped inner case-body. The plastic case-body acts as a shock absorber and can be colored to enhance the appearance of the watch.

3 Claims, 2 Drawing Figures WATERTIGI-IT WATCH CASES FOR WRIS WATCHES BACKGROUND OF THE INVENTION In order to provide the needed strength for assuring water-tightness watch cases are generally made of relatively strong materials such as stainless steel or brass. Colors are restricted to those of silver and gold. This limited range of materials does not provide as wide a range of colors as could be desired,particularly in view of the fact that dials can be made in a wide variety of colors.

Furthermore, in the interest of minimizing the weight of the wristwatch, it is desirable to use relatively thin case materials. However, such case materials are subject to defacement by relatively minor impact.

SUMMARY OF THE INVENTION The metal, inner case-body of awatch is made in ring shape, and a plastic outer case-body encloses the metal, inner case-body. The plastic outer case-body engages the metal, inner case-body and is held thereto by a metal bezel, made of metal and fixed into the inner case-body at the upper portion thereof. The plastic outer case-body, in general, is colored in order to enhance the appearance of the watch.

Accordingly, an object-of the present invention isto provide a watch case which is lighter in weight than conventional watch cases.

Another object of the inventionis toprovide a watch case which is more resistant to defacement by impact or shock.

A further object of the invention is to provide a watch case of enhanced appearance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of a conventional watch case for a wrist watch;

FIG. 2 is a cross sectional view of one embodiment of a watch case for a wrist watch according to'the invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to watertight watch cases made of plastic materials for wrist watches. Conventional watertight watch cases usually comprise a case body 1 provided with a band attaching lug 4, a bezel 2 engaging the upper projected portion of case body 1 with a certain interference, crystal 3, a case back 5 and a packing 6. This watch is constructed so that crystal 3 is compressed into the case body 1 with a certain interference, the outer peripheral wall of crystal 3 and the inner peripheral wall of the case body 1 are fitted rigidly and further packing 6 is deformed by screwing the case back 5 into the case body 1 in order to ensure the watch being watertight.

With the above-mentioned construction, mechanical strength is required in the interference portion or a screwing portion of a watch case. Thus metal'materials such as stainless steel or brass have been applied to a watch case.

However, these materials are practically restricted in coloring, namely restricted to silver and gold. Thus watches of various colors could'not be obtained.

' user, therefore, feels uncomfortable when wearing it on his wrist. Also, in the production of such watch cases, made of metals, the difficult work, such as cutting or pressing are required in addition to extensive time and thereby making the cost run very high. Since the conventional watch cases are made mostly of metals, rust is apt to generate thereon when subjected to moisture or water, thus causing the life of the case to be very short.

One the other hand, the purpose of the present invention is to eliminate the above-mentioned defects and to provide a watertight watch with a case made of plastic material. Plastic has the following merits, i.e., high workability, optional coloring and lightness in weight, while it has the following disadvantages, i.e. poor mechanical strength. For this reason, it has not been applied to a watertight watch which requires the mechanical strength but sometimes applied to only non-watertight watches with relatively low cost.

The present invention makes it possible to apply plastic material to a watertight watch by employing the construction as shown in FIG. 2.

Referring now to the embodiment shown in FIG. 2, 7 is an outer case body made of plastic material. 8 is a ring-shaped inner case body made of a metal, and engaged with crystal 10 and case back 11 made of a metal. 9 is a bezel made of a metal and fixed into the inner case body 8 at the upper portion of the outer case body 7 with a certain interference. 12 is a packing and 13 is a flat-surface formed in the periphery of the inner casebody 8 to receive the outer case body 7. Further the embodiment has such construction that the outer case body 7 is fitted to the periphery of the inner case body 8 from the upper side and interposed between the flat surface 13 of the inner case body 8 and the bottom of the bezel 9 fixed to the upper portion of the inner case body 8. The outer case body 7 is secured to the inner case body 8.

Concerning watertightness of the case above-mentioned, it is constructed so as to ensure it being watertight in the same manner as in the commonly used watch cases. The crystal 10 is compressed into the inner case body 8 with certain interferences both in the inner periphery of the inner case body 8 and in the outer periphery of the crystal 10 so as to fit rigidly with each other. The case back 11 is then screwed into the inner case body 8 and the packing 12 is deformed in order to ensure it being water tight.

In this case the connection between the outer case body 7 and the inner case body 8 may be other means, for example, by screws, engaging means, deformation by heat or adhesives.

As is apparent from the above description, a watch case according to the present invention is divided into two parts in its case-body portion, i.e., an inner case body portion requiring mechanical strength and an outer case body-portion (visible portion from the outside)-requiring medium mechanical strength, the inner case body portion being made of a metal and the outer case body portion being made of plastic material. Con- 'cer'ning watertightness, this watch gives the same performance as the conventional metal watch. Moreover, as the outer case body portion is made of plastic material, the coloring can be optionally selected and various colors of watches can be obtained.

Besides, in this case, the coloring is not applied to the foundation of the case as in plating or painting, but can be applied to the plastic itself, and the initial color can be maintained for a long time without peeling. Further, the color of the case can be matched with that of the band or dial, or patterns can be suited to each other, and further suitable color arrangement can be applied between the parts. The outer case body made of plastic material is easily formed by the injection molding. As the inner case body, made of a metal, is in a form of a ring, the pressing from a sheet material as usual is not required. This allows the mass-scaled production and the reduction in the cost of production. Thus watches with low costs can be supplied to the market.

Since the outer case body is made of plastic material, it is very light in weight, and when wearing it on the wrist, one does not feel uncomfortable.

The conventional watch case made of a metal has been restricted in form in machining and only the case with relatively simple shape could be realized. Now, however, the outer case body portion can be made by the injection molding. This makes it possible to produce the case of the complicated shape, and many watches in great variety of designs can be obtained.

By the injection molding above mentioned, some means, i.e., projected portion, etc., can be easily formed in the inner wall of the outer case body in order to prevent the rotation force caused between the outer case body and the inner case body by turning the screws of the case back. Furthermore, as the outer case body portion is made of plastic material which has an elasticity, if the watch should be carelessly dropped, it

can absorb a shock and prevent the timepiece mechanism from breaking. In addition, rust does not generate on it.

While the preferred embodiment of the invention, i.e., the watch case with the case back by screws, has been illustrated and described, it is to be understood that the present invention is not limited to the precise construction herein disclosed and can be applied to the other cases such as snap type or one-piece case and the same effect can be obtained.

As can be understood from the description above, the watch case, according to the invention, has both the merits of the metal case and the plastic case. Therefore, the present invention will have various good effects on the design or the function of the watertight watch cases for wrist watches.

What is claimed is:

1. A watertight watch case for a wrist watch comprising a ring-shaped inner metal case body having front and rear portions, said inner case body having an outwardly facing shoulder thereon proximate said rear portion, an outer case body of plastic material surrounding said inner case body and resting against said shoulder, and means in engagement with said inner case body for holding said outer case body against said shoulder.

2. A watertight watch case as defined in claim 1, wherein said outer case-body is held to said inner casebody by a bezel engaging said inner case-body.

3. A watertight watch case as defined in claim 1, wherein said outer case-body is colored.

Claims (3)

1. A watertight watch case for a wrist watch comprising a ringshaped inner metal case body having front and rear portions, said inner case body having an outwardly facing shoulder thereon proximate said rear portion, an outer case body of plastic material surrounding said inner case body and resting against said shoulder, and means in engagement with said inner case body for holding said outer case body against said shoulder.

2. A watertight watch case as defined in claim 1, wherein said outer case-body is held to said inner case-body by a bezel engaging said inner case-body.

3. A watertight watch case as defined in claim 1, wherein said outer case-body is colored.

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