Watch Case

Abstract

A watertight watch case wherein the central portion of the casing and the floor thereof consist of one piece and the watch crystal is retained via its clamping edge by means of an annular body seated upon the central portion of the casing. According to the invention, there is provided a sealing and retaining ring member which is clamped on the one hand between the outer surface of the clamping edge of the watch crystal and the outer surface of an annular projection of the casing central portion which is directed towards the watch crystal and on the other hand the inner surface of the annular body.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a new and improved construction of watertight watch case or casing wherein the central portion of the casing and the floor are formed of one piece or integrally, and the watch crystal is retained via its clamping edge by means of an annular body which is placed upon the casing central portion.

Watertight watch cases wherein the central portion of the casing and the back consist of one piece and the watch crystal is retained with the aid of its clamping edge by an annular body pushed onto the casing portion have the advantage of being easily fitted and therefore are especially suitable for inexpensive watches.

On the other hand, such type watch cases were only suitable for the mounting of watch crystals which were elastic to a certain degree, and additionally possessed the drawback that a comparatively large number of fitting surfaces or seats had to be fabricated and that they were only suitable for round watches.

To eliminate that disadvantage, it has already been proposed in Swiss patent 387,550 to provide a combined waterproof joint and retaining ring clamped between the outer face of the clamping edge of the watch crystal and the outer face of an annular prolongation of the central portion of the casing facing toward the watch crystal and the inner face of the annular body. In this instance, for the axial fixation of the position of the combined waterproof joint and retaining ring, undercut annular grooves were cut into the inner face of the annular body, into which grooves there engaged correspondingly shaped lateral annular prolongations of the combined waterproof joint and retaining ring. Owing to the expense of producing such type securing means, the advantage represented by the possibility of inexpensive manufacture was again offset.

SUMMARY OF THE INVENTION

Hence, it is a primary object of the present invention to provide a new and improved construction of watch case or casing which is more versatile than the prior art constructions of cases and is not associated with the aforementioned drawbacks and limitations discussed above.

Another and more specific object of the present invention relates to a new and improved construction of watch case of the previously mentioned type which, without impairing its watertightness, can also possess a non-circular configuration and likewise is suitable for the assembly of hardened crystals or glass, and furthermore, possesses fewer fitting surfaces or seats.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the invention is generally manifested by the features that there is provided a sealing and retaining ring member which, on the one hand, is clamped between the outer surface of the clamping edge of the watch crystal and the outer surface of an annular projection of the casing central portion which is directed towards the watch case and, on the other hand, the inner surface of the annular body. The casing central portion is provided at the region of its upper end with an inwardly directed ring-shaped shoulder bounded at the inside by the annular projection.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 is a fragmentary sectional view of a first embodiment of inventive watch case;

FIG. 2 is a fragmentary sectional view through a second embodiment of inventive watch case.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Describing now the drawings, in FIG. 1 there is illustrated a first examplary embodiment of watch case designed according to the teachings of the present invention wherein the casing 20 comprises a floor or back 1 which together with the central portion 2 of the casing 20 is fabricated from a single-piece or integrally with regard to one another. The casing central portion 2 is equipped at the side facing away from the casing floor 1 with a protruding annular or ring-shaped projection 3 and an inwardly directed annular or ring-shaped shoulder 4 bounded at the inside by the annular projection 3. An annular or ring-shaped body 5 placed or seated upon the casing central portion 2 possesses an internal or inner recess 6 which is limited towards the outside at the side of the watch crystal 8 by the crystal rim or collar 7. The watch crystal 8 is freely inserted into the crystal rim 7 and is located by means of its clamping edge 9 above the annular projection 3, the outside surface 3a of which is turned or otherwise suitably machined to the external diameter of the crystal 8 i.e. the outside surface of the clamping edge 9a and the outside surface 3a lie in a common substantially cylindrical surface.

At the annular or ring-shaped compartment 21 formed by the inner surface 6a of the recess 6 as well as the outer surface 9a at one side of the clamping edge 9 of the watch crystal 8 as well as the annular projection 3, there is now clamped a sealing and retaining ring member 10 formed of a suitable elastic sealing material, preferably plastic, such as for instance that known to the art under trademark "ISOFRANE," and available from Les Isolants Francais, of Paris, France. This sealing ring member 10, which bears by means of its inner surface 10a against the clamping edge 9 of the watch crystal 8 and covers the joint 22 between such clamping edge 9 and the annular projection 3, serves both to secure the crystal 8 as well as also to seal against the penetration of water. Owing to this double function of the sealing ring 10, there is rendered possible a very simple construction, by means of which it is sufficient to construct the outside of the annular projection 3 as a fitting surface or seat.

The assembly of the watch case takes place in the same manner as for all watch cases of this type in that initially the sealing ring member 10 is placed in conventional manner about the clamping edge 9 of the watch crystal 8 and the annular projection 3, and thereafter, with simultaneous compression of the sealing ring 10, the annular or ring-shaped body 5 is placed over both of these elements, as shown.

Turning now attention to the embodiment of FIG. 2, it is to be understood that the same reference characters have been employed for the same or analogous components. In particular, the embodiment of FIG. 2 essentially differs from the first embodiment of FIG. 1, in that here the sealing ring 10 possesses a radially inwardly projecting rib or lip 11 which comes to lie between the underside of the clamping edge 9 of the watch crystal 8 and the top of the annular projection 3.

In both cases the described constructions allow for the fabrication of a watertight watch case which possesses only one fitting surface or seat, namely the outside surface of the annular projection 3 permits the use of hardened glass for the watch crystal and can be designed equally well as a round case or a fancy case.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims. ACCORDINGLY,

Claims

What is claimed is:

1. A watertight watch case comprising a casing having a central portion and a floor, said central portion and floor of said casing being formed of one-piece, a watch crystal possessing a clamping edge, a substantially annular body placed upon the central portion of the casing for retaining the watch crystal, said central portion of the casing having a substantially annular projection directed towards the watch crystal, said annular projection having an outer surface, said clamping edge of the watch crystal including an outer surface, said annular body having an inner surface, and a sealing and retaining ring member clamped between the outer surface of the clamping edge of the watch crystal and the outer surface of the annular projection and the inner surface of the annular body, said central portion of the casing including an upper region provided with an inwardly directed ring-shaped shoulder bounded at the inside by said annular projection, the outer surface of the clamping edge of the watch crystal and the outer surface of the annular projection being disposed in a common substantially cylindrical surface.

2. A watertight watch case as defined in claim 1, wherein the underside of the clamping edge of the watch crystal and the top of the annular projection are spaced from one another, the sealing and retaining ring member having an inwardly projecting rib extending into the space between the clamping edge and annular projection.

3. A watertight watch case as defined in claim 1, wherein the sealing and retaining ring member possesses essentially flat parallel walls, and said sealing and retaining ring member and said annular body being devoid of any undercut recesses.