Watertight Watchcase For Wristwatches

Abstract

An internal capsule constituted by a vessel made of a soft plastic material and by the watchglass is kept closed by an external capsule constituted by two metallic pieces fixed onto one another by screws. These pieces press the glass axially on the upper edge of the lateral portion of the plastic vessel so as to form a tight seal therebetween. The watch movement is held in place within the internal capsule by clamping. The lateral portion of the plastic vessel is therefore transversely compressed between the movement and one of the metallic pieces of the outer capsule.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to watertight watchcases for wristwatches and in particular to watchcases of the type in which the watch movement is located in an internaltight capsule composed of a vessel of soft plastic material and the watchglass, an external capsule, which comprises the watchcase bottom and a bezel, encompassing the internal capsule.

2. Description of the Prior Art

With the known watchcases of this type the glass has a cup shape. It is made integral with a peripheral sidewall extending in an axial direction and the plastic vessel is inserted into this glass wall so as to tightly engage the same. The tight closure of the internal capsule is accordingly due to the radial pressure exerted on a portion of the plastic vessel, i.e., to a pressure exerted in a direction perpendicular to the watchcase axis. The tightness of the internal capsule thus depends the more on the manufacturing tolerances of the components of the external capsule, of the plastic vessel and of the glass as the vessel portion engaging the glass is thin. Moreover, the joint between the two components of the internal capsule can only ensure a tight seal of this capsule if the plastic vessel and the glass engage one another along a circular cylindrical surface. In other words, the known technique cannot be resorted to with non circular watches having a non circular glass. Finally, the known technique is also useless with watches having a sapphire glass or a hardened mineral glass.

The problem is accordingly to provide a watertight watchcase for wristwatches, in which the means ensuring the tightness are not only utilizable whatever shape the watchcase may have, but also competitive with respect to the standard means used till now in each specific case.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to ensure the tight closure of the internal capsule of the watchcase exclusively by causing a peripheral portion of the glass inner side surface to be pressed in a direction parallel to the watchcase axis on the upper edge of the lateral portion of the plastic vessel, that pressure of the glass on the vessel being ensured by the external capsule of the watchcase comprising a bottom piece engaging the bottom portion of the plastic vessel and having a peripheral flange with a flat upper surface surrounding said vessel, a bezel engaging a peripheral portion of the outer side surface of the glass and having a peripheral flange with a flat lower surface surrounding said vessel, and removable securing means firmly holding said flat upper surface of the bottom piece and said flat lower surface of the bezel in abutting engagement with each other.

Since the external capsule thus holds the two components of the internal capsule in a predetermined position with respect to each other, it determines the extent of the axial pressure of the glass on the vessel. Accordingly the flat surfaces of said peripheral flanges need only be located on the two pieces of the external capsule in such positions with respect to the portions of said pieces which engage the glass and the vessel bottom, respectively, that a tight seal will be ensured between the glass and the vessel while preventing, however, the vessel and the glass from being subjected to an excessive stress.

It is also an object of the invention to enable mounting a predetermined type of watch movement in casings having quite different shapes by means of one and the same type of plastic vessel. For this purpose, the lateral portion of the plastic vessel need only have an inner and an outer side surface, the contours of which are adapted to that of the watch movement and to that of said peripheral flanges of the two pieces of the external capsule, respectively, in such a manner as to cause the lateral portion of the plastic vessel to be pressed transversely between the watch movement and at least one of said peripheral flanges. This transverse pressure will, indeed, cause a clamping action to be exerted on the watch movement in order to hold the latter transversely and axially in place within the internal capsule.

Still a further object of the invention consists in permitting different movements of one and the same caliper, i.e., with a base plate having the same sizes, to be encased by means of one and the same vessel type. Therefore, a rigid ring need only be inserted in the lateral portion of the plastic vessel so as to extend over a part of that lateral portion from the vessel bottom. This ring will then serve as a support for the watch movement and hold the same in the desired axial position within the internal capsule.

Another object of the invention consists in providing a tight seal under the best possible conditions between the glass and the plastic vessel without having to hold unusually narrow margins in manufacturing the different components of the watchcase. A continuous rim can, for that purpose, be formed integrally with the lateral portion of the plastic vessel so as to project axially upwards from the upper edge thereof, said rim having a rounded cross section and engaging the peripheral portion of the inner side surface of the glass.

Still another object of the invention is to enable keeping usual margins in the manufacture of all the watchcase parts. A peripheral rim can therefore be formed integrally with the lateral portion of the plastic vessel so as to project radially outwards from the outer side surface thereof, said rim extending all round said lateral portion and having a rounded cross section and said lateral portion engaging the peripheral flange of one of the two pieces constituting the external capsule by means of said rim.

Still further objects of the invention will become apparent in the course of the following description.

BRIEF DESCRIPTION OF THE DRAWING

Two embodiments of the watchcase according to the invention are represented diagrammatically and by way of example in the accompanying drawing.

In the drawing:

FIG. 1 is a plan view of the first embodiment;

FIGS. 2, 3 and 4 are sectional views along lines II--II, III--III, and IV--IV, respectively, of FIG. 1, and

FIG. 5 is a sectional view similar to that of FIG. 3 but showing the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The watchcase represented in FIGS. 1-4 has a rectangular shape. It is adapted for receiving a circular watch movement 1 carrying a dial 2 which extends radially outwards beyond the edge of the watch movement 1 and has a shape similar to that of the watchcase. The movement 1 is inserted in a vessel 3 comprising a bottom portion covering the bridge side of the watch movement and a lateral portion extending upright form the periphery of the bottom portion. The inner side surface of the lateral portion of vessel 3 has a contour adapted to that of movement 1 so as to encompass the edge of this movement. Movement 1 bears axially on the upper edge of a metallic ring 4 which is inserted in the lateral portion of vessel 3 so as to extend over a part of that lateral portion from the bottom of vessel 3. A continuous rim 5 is formed integrally with the lateral portion of vessel 3 so as to project axially upwards from the upper edge of the lateral portion of vessel 3. Rim 5 has a rounded cross section and it extends all round the dial 2 above the visible upper surface thereof. The watch glass 6 has a peripheral portion constituted by a stepped flange 7. The lower surface of flange 7 forming part of the inner side surface of the glass lies on rim 5.

The vessel 3 is made out of a soft plastic material so that rim 5 engages the glass flange 7 while forming a tight seal between vessel 3 and glass 6 as soon as the latter is pressed axially to some extent on rim 5.

Vessel 3 carries a tube 8 for the passage of the usual winding and hand-setting stem of the watch movement. Tube 8 is tightly fixed to vessel 3. The tightness of the stem passage itself through tube 8 is ensured in the usual manner by the winding and hand-setting crown 9 which carries a female stem part (not shown) adapted for being clutched to the male part 10 of the stem portion carried by movement 1.

By means of rim 5 and tube 8, vessel 3 constitutes a tight internal capsule together with glass 6 and crown 9 for the watch movement 1. The only condition which that capsule has to satisfy for that purpose is that glass 6 has to be pressed axially on rim 5 with a predetermined strength. That condition for the tight closure of the internal capsule enclosing the watch movement is satisfied by means of the two metallic pieces 11 and 12 of the watchcase, which constitute together an external capsule thereof. Piece 11 includes the watchcase bottom 13 and piece 12, the bezel 14. The external bottom piece 11 further includes a peripheral flange having an upper flat surface 11a surrounding the vessel 3 of the internal capsule and the second metallic piece of the external capsule similarly comprises a peripheral flange having a flat lower surface 12a which similarly surrounds vessel 3. When the watchcase is fully assembled the flat upper surface 11a of the bottom piece and the flat lower surface 12a of the bezel bear on one another. These two flat surfaces 11a, 12a are held in abutting engagement by means of four screws 15 provided at the corners of the watchcase. The screws 15 extend through bores 16 of piece 11 and are screwed into sleeves 17 secured to piece 12 within blind holes of the latter.

When the flat surfaces 11a and 12a of pieces 11 and 12 of the watchcase external capsule bear on one another, bezel 14 lies at a predetermined distance from bottom 13. Since the internal capsule of the watchcase is clamped axially between bottom 13 and bezel 14, the distance between these two parts need only be properly chosen in order that bezel 14 engaging the upper surface of the glass flange 7 causes the lower surface thereof to be pressed axially on rim 5 of vessel 3.

It will be observed that the two pieces 11 and 12 of the external capsule of the watchcase described heretofore have not been subjected to any particular machining operation either for receiving the movement 1 and holding the same within the watchcase or for ensuring the tight closure of the latter. The means provided for firmly holding the watch movement within the internal capsule of the watchcase and those provided for ensuring the tight closure of the internal capsule do obviously also not depend on the outer shape of the pieces 11 and 12 constituting the external capsule. The outer shape of the external capsule does neither depend on the contour of the outer side surface of the lateral portion of vessel 3. To ensure encompassing the internal capsule by the external one pieces 11 and 12 thereof need only be provided with stamped recesses having contours adapted to that of vessel 3.

Whatever outer shape the two pieces of the external capsule as well as the two pieces of the internal capsule of the watchcase may have, it will moreover always be possible to mount the watch movement tightly in the watchcase and to hold it firmly in place.

Vessel 3 can easily be manufactured, for instance by molding an elastomer, such as perbunam, buna, rubber, neoprene, silicone, viton, genthane, ethylene-propylene, polyacrylate, hypalon or vulcolan. Since most of these substances are soft, vessel 3 will provide for a resilient suspension of the movement 1 damping the impacts to which the external capsule may be subjected in use. In view of improving that suspension, two peripheral rims 18, 19 are formed integrally with the lateral portion of the vessel 3 so as to project radially outwards from the outer side surface thereof. Rim 19 is on the same level as the part 20 of the inner side surface of the lateral portion of vessel 3 extending above ring 4 and engaging a bearing surface of movement 1. Rim 19 can easily be given such sizes when molding vessel 3 that part 20 of the inner side surface of the lateral portion of vessel 3 bears against the corresponding bearing surface of movement 1 strongly enough in order to hold movement 1 axially in place within vessel 3.

Cutouts 11b, 12b are provided in pieces 11 and 12 for the passage of tube 8 and piece 11 carries bars 21 for attaching the wristband to the external capsule of the watchcase. Water infiltration between piece 11 and vessel 3 can be avoided by providing the passage for tube 8 fully within piece 12. In such a modification, the glass would cause the outer part of the lateral portion of the vessel to be pressed on the part of surface 11a projecting radially inwards from piece 12.

In the first embodiment described, tube 8 is secured to vessel 3 by gluing. Glues compatible with the material of the vessel can easily be found on the market. They have the property to adhere to the metal and the material of the vessel to such an extent that it is no more possible to remove the tube from the vessel without tearing away some portion of the latter. In addition to gluing or alternatively, it would also be possible to provide the tube with a collar which would be embedded in the mass of the vessel.

The watchcase of the embodiment described comprises a usual glass made out of an organic plastic material. Without modifying the technique resorted to for ensuring the tight closure of the internal capsule as well as for securing the watch movement therein, it would also be possible to provide the watchcase with a hardened mineral glass or a sapphire as shown in the second embodiment represented in FIG. 5. Since machining operations on hardened mineral glasses as well as on sapphires have to be avoided as far as possible, the glass 6a of the second embodiment is constituted by a flat plate having the desired contour. In this embodiment, the peripheral portion of the glass inner side surface is permitted to lie on the vessel upper edge for sealing the internal capsule by providing the plastic vessel 3 with a continuous rim 5a higher than in the first embodiment. The peripheral portion of dial 2a is bent upwards as shown at 22 in order to hide rim 5a.

In this second embodiment, the visible face of the watch can be given a plurality of different shapes (circular, oval, square, rectangular, triangular, polygonal, etc.) without modifying the substantial manufacturing operations of piece 12c of the external capsule of the watchcase. In a first manufacturing step piece 12c can indeed be made with a continuous central web. According to the desired shape of the visible dial part, a corresponding opening is then stamped in this web. Finally, the inner edge of piece 12c need only be rounded to obtain the bezel 14a shown in the drawing.

Due to the softness of the material used for molding vessel 3, the latter can compensate for the usual differences due to the manufacturing tolerances of the metallic pieces constituting the external capsule of the watchcase.

Tests made with the disclosed watchcases have shown that the latter do not allow any water infiltration into the internal capsule containing the watch movement either at the atmospheric pressure or at pressures of several atmospheres. The last result can be understood without difficulty. Since the glass can freely move in a direction parallel to the watchcase axis within the external capsule thereof, an increase of the outer pressure has as a result to produce a shifting of the glass towards the inside of the watchcase thus increasing its pressure on the vessel rim on which it bears. The internal capsule of the watchcase, which tightly encloses the watch movement 1, can accordingly be used in usual watertight watches as well as in watertight watches for divers.

The invention permits a wide choice of watch models to be quickly prepared at a competitive price, because of the simplicity of the tools required for molding vessel 3.

Claims

What is claimed is:

1. A watertight watchcase for wristwatches comprising, in combination, a vessel made out of a soft plastic material and having a bottom portion and a lateral portion extending upright from the periphery of the bottom portion and having an upper edge, a watchglass having an inner and an outer side surface, the glass inner side surface having a peripheral portion lying on the upper edge of the lateral portion of the plastic vessel, an external bottom piece engaging the bottom portion of the plastic vessel and having a peripheral flange with a flat upper surface surrounding said vessel, an external bezel engaging a peripheral portion of the outer side surface of the glass and having a peripheral flange with a flat lower surface surrounding said vessel, and removable securing means firmly holding said flat upper surface of the bottom piece and said flat lower surface of the bezel in abutting engagement with each other, thereby causing the glass to be pressed on the vessel to a predetermined extent, said plastic vessel and said glass constituting an internaltight capsule for the watch movement, and said bottom piece and said bezel constituting an external capsule encompassing said internal capsule and ensuring the closure thereof by holding said vessel an said glass in a predetermined position with respect to each other, the tight seal between said plastic vessel and said glass being exclusively ensured by the glass pressing in a direction parallel to the watchcase axis on the upper edge of the lateral portion of the plastic vessel under the action of said external capsule, the extent of the axial pressure of the glass on the vessel being determined by the external capsule so as to ensure a tight seal between the glass and the vessel, but to prevent the vessel and the glass from being subjected to an excessive stress.

2. A watertight watchcase according to claim 1, the contours of the inner side surface and of the outer side surface of said lateral portion of the plastic vessel being adapted in such manner to that of the watch movement to be received by said internal capsule and to that of said peripheral flanges, respectively, as to cause said lateral portion of the plastic vessel to be pressed in a direction perpendicular to the watchcase axis between the watch movement and at least one of said peripheral flanges thus causing a clamping action to be exerted on the watch movement and holding this movement transversely and axially in a predetermined position within said internal capsule.

3. A watertight watchcase in combination, a vessel made out of a soft plastic material and having a bottom portion and a lateral portion extending upright from the periphery of the bottom portion and having an upper edge, a watchglass having an inner and an outer surface, the glass inner side surface having a peripheral portion lying on the upper edge of the lateral portion of the plastic vessel, an external bottom piece engaging the bottom portion of the plastic vessel and having a peripheral flange with a flat upper surface surrounding said vessel, an external bezel engaging a peripheral portion of the outer side surface of the glass and having a peripheral flange with a flat lower surface surrounding said vessel, removable securing means firmly holding said flat upper surface of the bottom piece and said flat lower surface of the bezel in abutting engagement with each other, thereby causing the glass to be pressed on the vessel to a predetermined extent, said plastic vessel and said glass constituting an internal tight capsule for the watch movement, and said bottom piece and said bezel constituting an external capsule encompassing said internal capsule and ensuring the closure thereof by holding said vessel and said glass in a predetermined position with respect to each other, the tight seal between said plastic vessel and said glass being exclusively ensured by the glass pressing in a direction parallel to the watchcase axis on the upper edge of the lateral portion of the plastic vessel under the action of said external capsule, the extent of the axial pressure of the glass on the vessel being determined by the external capsule so as to ensure a tight seal between the glass and the vessel, but to prevent the vessel and the glass from being subjected to an excessive stress, the contours of the inner side surface and of the outer side surface of said lateral portion of the plastic vessel being adapted in such manner to that of the watch movement to be received by said internal capsule and to that of said peripheral flanges, respectively, as to cause said lateral portion of the plastic vessel to be pressed in a direction perpendicular to the watchcase axis between the watch movement and at least one of said peripheral flanges thus causing a clamping action to be exerted on the watch movement and holding this movement transversely and axially in a predetermined position within said internal capsule and, a peripheral rim formed integrally with said lateral portion of the plastic vessel and projecting radially outwards from the outer side surface thereof, said rim extending all round said lateral portion and having a rounded cross section and said lateral portion engaging said peripheral flange by means of said rim, thereby producing said compression in a direction perpendicular to the watchcase axis in said lateral portion of the plastic vessel and causing the watch movement to be clamped and held transversely and axially within said internal capsule.

4. A watertight watchcase, in combination, a vessel made out of a soft plastic material and having a bottom portion and a lateral portion extending upright from the periphery of the bottom portion and having an upper edge, a watchglass having an inner and an outer side surface, the glass inner side surface having a peripheral portion lying on the upper edge of the lateral portion of the plastic vessel, an external bottom piece engaging the bottom portion of the plastic vessel and having a peripheral flange with a flat upper surface surrounding said vessel, an external bezel engaging a peripheral portion of the outer side of the glass and having a peripheral flange with a flat lower surface surrounding said vessel, removable securing means firmly holding said flat upper surface of the bottom piece and said flat lower surface of the bezel in abutting engagement with each other, thereby causing the glass to be pressed on the vessel to a predetermined extent, said plastic vessel and said glass constituting an internal tight capsule for the watch movement, and said bottom piece and said bezel constituting an external capsule encompassing said internal capsule and ensuring the closure thereof by holding said vessel and said glass in a predetermined position with respect to each other, the tight seal between said plastic vessel and said glass being exclusively ensured by the glass pressing in a direction parallel to the watchcase axis on the upper edge of the lateral portion of the plastic vessel under the action of said external capsule, the extent of the axial pressure of the glass on the vessel being determined by the external capsule so as to ensure a tight seal between the glass and the vessel, but to prevent the vessel and the glass from being subjected to an excessive stress, and a continuous, uninterrupted rim formed integrally with said lateral portion of the plastic vessel and projecting axially upwards from said upper edge thereof, said rim having a rounded cross section and engaging said peripheral portion of the inner side surface of the watch glass.

5. A watertight watchcase, in combination, a vessel made out of a soft plastic material and having a bottom portion and a lateral portion extending upright from the periphery of the bottom portion and having an upper edge, a watch glass having an inner and an outer side surface, the glass inner side surface having a peripheral portion lying on the upper edge of the lateral portion of the plastic vessel, an external bottom piece engaging the bottom portion of the plastic vessel and having a peripheral flange with a flat upper surface surrounding said vessel, an external bezel engaging a peripheral portion of the outer side surface of the glass and having a peripheral flange with a flat lower surface surrounding said vessel, removable securing means firmly holding said flat upper surface of the bottom piece and said flat lower surface of the bezel in abutting engagement with each other, thereby causing the glass to be pressed on the vessel to a predetermined extent, said plastic vessel and said glass constituting an internal tight capsule for the watch movement, and said bottom piece and said bezel constituting an external capsule encompassing said internal capsule and ensuring the closure thereof by holding said vessel and said glass in a predetermined position with respect to each other, the tight seal between said plastic vessel and said glass being exclusively ensured by the glass pressing in a direction parallel to the watchcase axis on the upper edge of the lateral portion of the plastic vessel under the action of said external capsule, the extent of the axial pressure of the glass on the vessel being determined by the external capsule so as to ensure a tight seal between the glass and the vessel, but to prevent the vessel and the glass from being subjected to an excessive stress, and a rigid ring inserted in said lateral portion of the plastic vessel so as to extend over a part thereof from said bottom portion, said ring serving as a support for the watch movement in order to hold said movement in a predetermined axial position within said internal capsule, a peripheral rim being formed integrally with the part of said lateral portion extending above said ring and projecting radially outwards from the outer side surface of said lateral portion, said rim having a rounded cross section and extending around said lateral portion on the same level as the watch movement and engaging said peripheral flange thereby causing said lateral portion to clamp the watch movement and to hold it transversely and axially within said internal capsule.