GB2156111A

GB2156111A - Watch-case with crown

Info

Publication number: GB2156111A
Application number: GB08506259A
Authority: GB
Inventors: Francis Bourquin
Original assignee: Catena SA
Current assignee: Catena SA
Priority date: 1984-03-14
Filing date: 1985-03-11
Publication date: 1985-10-02
Also published as: JPS60210792A; IT1181600B; CH657956GA3; GB8506259D0; IT8547807A0

Abstract

The watch-case comprises a caseband (1) has a radial orifice (25), through which there passes a stem ending in a crown and a groove (30) formed as a lateral opening (31). A bridge (6) situated in the lateral opening is solid with a means of attachment (35) (Fig. 4a) having a shape which enables it to be fitted into the groove (30). The bridge (6) surrounds and protects the crown (4) by means of an aperture (9). The radial orifice (25) may be provided with a pipe (24) which, together with the crown (4), forms a watertight joint. The bridge is notched at (36) to fit around the pipe (24). <IMAGE>

Description

SPECIFICATION Watch-case with crown The present invention refers to watch-cases which have winding-stems and crowns. More particularly, it concerns-a water-resistant watch-case with an arch or bridge passing over the crown in order to protect it from shocks and jars, mainly when it is in the pulled-out position. A watch-case of this kind affords opportunities for the creation of new forms.

Watch-cases with winding-stems and crowns have been commonly used for a iong time past. In fact, all mechanical watches are fitted with them. In its normal pushed-in position, the crown enables one to wind the mainspring; in its first pulled-out position, it is used for setting the watch to the right time. If the water is equipped with calendar work, it can be set to the right time and date by means of the crown in its second pulled-out position.

In an electronic watch, which has no mainspring, the winding-stem and the crown serve no useful purpose. Corrections, for example, can be made by means of pushpieces, which actuate contacts. The present tendency, however, is to provide electronic watches with a crown in addition, which is fixed to a control-stem coupled to contacts. In its normal position, the crown generally has no function whatever; in its pulled-out positions, however, it is used for setting the watch to the right time and date by means of manipulations similar to those which are used in the case of mechanical watches.

Owing to its construction, the winding- or control-stem with its crown represents the delicate and vulnerable part of a watch. What is more, in relation to the general form of a conventional watch-case, the crown constitutes a protuberance which makes it highly subject to shocks and jars, especially when it is in its pulled-out positiOn.

A familiar method of making the crown less vulnerable consists in protecting it by means of a pair of snugs, as shown in Fig. 1. This drawing shows part of a caseband 1, having an annular general form, of a watch-case which is not shown. This caseband has a radial orifice or hole 2, through which there passes a winding- or control-stem 3, hereinafter called simply the "stem", capable of turning about the axis a-a'. On the outside of the case, the stem 3 ends in a cylindrical crown 4.

The system protecting the crown is composed of a first snug 5a, fixed on the caseband 1 in the immediate vicinity of the crown, and of a second snug 5b, fixed on the caseband in a position which, in relation to the orifice 2, is symmetrical with the first snug.

The height of the snugs is approximately equal to that of the crown, while their thickness is smaller than the diameter of the crown in order to facilitate manipulation.

The snugs 5a and 5b give the crown 4 effective protection from shocks which are directed parallel to the plane of the caseband 1, when the crown is in its normal position.

The protection is less good when the shocks are directed perpendicularly to the plane of the caseband, and it is practically non-existent when the crown is pulled out.

Another device, which in itself is known, for ensuring better protection of the crown when it is pulled out, is shown in Fig. 2. The same parts have the same references: this drawing shows the caseband 1, which in this case is of polygonal shape, the orifice 2, the stem 3 and the crown 4. The protective device is made in the form of a bridge 6, passing above the crown 4. It consists of two feet 2a and 2b, which are solid with the caseband 1 and are connected by an arch 8. The crown is thus accommodated inside an opening 9, the width of which is greater than the diameter of the crown and the height of which is sufficient to enable the crown to take up its pulled-out position. Lastly, the thickness of the bridge 6 is smaller than the diameter of the crown 4 so that it can be manipulated more easily.

In such a construction, however, the arch 8 makes it impossible to fit or to extract the stem 3 with its crown 4 from the outside, as can be done when conventional watch-cases are used. To make this operation possible, the caseband 1 must be capable of dividing into two parts at the level of the radial orifice 2, so as to free the point where the stem passes through the caseband. The bridge can then be solid with one of the two parts of the caseband 1, without preventing the stem from being fitted or extracted perpendicularly to the plane of the drawing.

The necessity of using a two-part caseband in the known cases which are fitted with a protective bridge is a constraint which complicates the construction and increases its cost, while making it impossible to guarantee watertightness at the level of the stem.

To avoid these disadvantages, the watchcase in accordance with the invention is particularly remarkable in so far as it comprises -a caseband with an annular portion delimiting an internal space for fitting a movement, and having an upper side for taking a glass and a lower side for taking a caseback, a radial orifice in the annular portion for permitting the passage of a stem carrying at one of its two ends a crown which can turn with the stem round an axis of rotation, and a groove formed in the annular portion and presenting an external opening round the radial orifice; and -a bridge, situated at the point where the groove opens and passes above the crown, solid with a means of attachment provided with a slot allowing the stem to pass, this means of attachment being so shaped that it can enter the groove of the caseband.

One advantage of the invention is that the caseband, being made in only one piece, is simpler to machine than a caseband which can be divided into two parts.

Another advantage of the invention is that it permits the construction of water-resistant cases by means of well-known and tested techniques, in particular at the point where the stem passes through the caseband.

Other characteristics and advantages of the invention will appear from the following description, made in conjunction with the attached drawings and giving an explanatory, though in no wise limitative, illustration of an advantageous form of construction of such a watercase fitted with a crown. In these drawings, the same references denote the same parts: Figure 1 is a plan-view of a device for protecting the crown which has already been mentioned and is known from earlier work, using snugs; Figure 2 shows another device for protecting the crown, which has already been mentioned and is known from earlier work, using a bridge; Figure 3a is a view, from above, of one form of execution of the band of a waterresistant watch-case in accordance with the invention; Figure 3b is a sectional lateral view of the caseband shown in Fig. 3a:: Figure 3c is a view, from below, of the watch-case shown in Fig. 3a and 3b; Figure 4a is a view, from above, of one form of execution of the means of attachment for the protective bridge of a watch-case in accordance with the invention: Figure 4b is a sectional lateral view of the means of attachment for the protective bridge, shown in Fig. 4a; Figure 4c is a view, from below, of the means of attachment for the protective bridge, shown in Fig. 4a and 4b; Figure 5a, 5b and 5c are respectively a view from above, a lateral view and a sectional view, from below, of the assembled caseband and protective bridge; Figure 6a is a partial plan-view of one form of execution, in accordance with the invention, of the protective bridge and of the crown in its pushed-in position; and Figure 6b shows how the crown and the protective bridge shown in Fig. 6a fit together when the crown is in its pulled-out position.

A particularly advantageous form of execution of a watch-case in accordance with the invention will now be described by way of an example.

Fig. 3a shows a caseband 1 of such a watch-case, as seen from above. This caseband, which has a circular general shape, comprises an annular portion 20, on which is fixed a glass 21 surrounded by a decorative bezel 22. Two pairs of horns 23, solid with the caseband 1, make it possible to fix, in the conventional manner, a wristband or bracelet which is not shown in the drawing. Lastly, a pipe 24 which is fixed to the annular portion 20 makes it possible to pass a stem a-a', which is not shown in the drawing, through the caseband 1. The crown is fitted upon the pipe 24 in such a way that it forms a waterresistant joint, without preventing the crown from turning round the axis a-a' of the stem or from sliding along the pipe so as to take up one or more pulled-out positions. In a mechanical watch, the stem is a winding-shaft.In an electronic watch, it is a control-rod actuating contacts in a movement with digital display, and in a movement with analogue display it may be a hand-setting device.

In Fig. 3b, the caseband 1 is shown in profile and in section; it shows the same elements 20, 21, 22, 23 and 24 as in the previous drawing, as well as a radial orifice 25, which is made in the annular portion 20 and has the pipe 24 driven into it. Fig. 3b also shows a groove 25, designed to take a press-on water-resistant caseback, which is not shown in the drawing. This caseback, with the glass 21 and the annular portion 20 of the caseback, delimits an inner volume 27 for fitting a movement. Lastly, Fig. 3b shows a groove 30, situated on the outside of the annular portion 20.

Fig. 3c shows the caseband 1 as seen from below, with the groove 30 appearing in the form of a circular ring with a lateral opening 31 round the pipe 24. In the example shown in the drawing, the groove 30 is also open laterally on the remainder of its periphery, except at the places where the horns 23 join the annular portion 20. This is not a necessity, however, and the groove 20 might have an outside lateral wall, except at the place where the lateral opening 31 is situated.

Fig. 4a shows from above a bridge 6 in accordance with the invention, composed of an arch 8 joined to two feet 7a and 7b, which are themselves solid with a means of attachment 35 having in this example the form of a closed circular ring. The bridge 6 spans a notch 36, which opens upwards and is wide enough to take the pipe 24. The inner part of the bridge 6 delimits an opening 9, which is so dimensioned that it affords enough room for the crown of the watch, in its pushed-in and pulled-out positions. The space between the feet 7a and 7b of the bridge 6 corresponds to the lateral opening 31, and the means of attachment 35 is so shaped that it can fit into the groove 30 of the caseband 1.

The external contour of the means of attachment 35, outside the bridge 6. must harmonize with that of the annular portion 20, with out necessarily being identical with it. Thus on the opposite side of the bridge 6, the means of attachment 35 presents a decorative motif 32 which, in this form of execution, extends beyond the outer part of the caseband 1.

Fig. 4b shows a sectional profile view of the bridge 6 and of the means of attachment 35 shown in the previous drawing. In this example, it will be seen that the notch 36 opens downwards. Lastly, Fig. 4c shows the same elements as seen from below.

The caseband 1 and the bridge 6, assembled so as to form a watch-case in accordance with the invention, are shown in Fig. 5a as seen from above. This assembly is made possible thanks to the lateral opening 31, which allows the bridge 6 to pass, to the shape of the means of attachment 35, which enables it to fit into the groove 30, and to the notch 36, which the pipe 24 can enter. In this execution, only the bridge 6 and the decorative motif 37 extend beyond the general contour of the caseband 1.

Fig. 5b is a sectional profile view of the assembled watch-case. It will be seen that in this execution, as the annular portion 20 comes to the same level as the means of attachment 35, the latter can be held in position by a press-on caseback (not shown in the drawing) which is of sufficient diameter and engages in the groove 26. Lastly, Fig. Sc shows the same watch-case assembled, as seen from below.

Of course, it is possible to envisage other forms of construction without departing from the principle of the invention.

For example, the groove 30 might be on the same side as the glass 21. The bezel 22 would then cover the means of attachment 35 for the bridge 6 and would hold it in position.

Instead of being contiguous with the caseband 1, the horns 23 might very well be solid with the means of attachment 35, which might have the form of an open ring. The caseband 1 and the bridge 6 with the means of attachment 35 may of course be made of different materials so that a novel decorative effect can be obtained. The present invention is also perfectly compatible with a shaped watch-case, of square design for example.

The main object of the bridge 6 is to protect the crown 4 from shocks, as has already been mentioned in connection with Fig. 2. Although the bridge gives excellent protection from shocks which are directed parallel to the plane of the caseband 1, it is absolutely useless as a means of protection from shocks which are directed perpendicularly to that plane, in which case the crown is particularly vulnerable when it is in the pulledout position.

This disadvantage can be avoided by means of a form of execution of the watch-case in accordance with the invention in which the bridge affords effective support for the crown in its pulled-out position. This is shown in Fig.

6a, as seen from above. In this drawing, the elements numbered 1, 2, 3, 4, 6, 7a, 8 and 9, as well as the axis a-a', have already been described in connection with Fig. 1 and 2. At the tip of the crown, there is a cabochon 10 in the form of a boss on the stem a-a Typically, the cabochon resembles a spherical cap. Similarly, the arch 8 of the bridge 6 has a hollow 11, the shape of which is complementary to that of the cabochon 10.

More precisely, the cabochon can serve its purpose only if it has a form which is not plane but, for example, convex, and is at least partially tangent to a first surface of revolution S' of the a-a', the second surface of revolution SS" being obtained by translation of the first surface S' along the axis a-a'.

If the arch 8 is at the right distance from the caseband 1, the crown being pulled out, the cabochon 10 will fit exactly into the hollow 11 of the arch 8, as shown in Fig. 6b.

This fitting-in effect provides the crown 4 with a rigid support when it is pulled out, but without preventing its rotation, thus attaining the desired object.

When the crown 4 is pulled out, the first and second surfaces of revolution, S' and S", are combined to form a single surface of revolution S of the axis a-a'. The cabochon 10 is then at least partially tangent to one side of the surface of revolution S and then the hollow 11 is at least partly tangent to the other side of that same surface.

Of course, the cabochon 10 might equally well be situated on the arch 8 and the hollow 11 might be made in the crown 4, without this arrangement departing from the principle of the invention. Moreover, in order to permit the rotation of the crown 4 in its pulled-out position, the surfaces delimiting the cabochon 10 and the hollow 11 should preferably be smooth. However, one or both of these surfaces may present decorative motifs, for instance suitably disposed facets or grooves, without making it more difficult to turn the crown. The cabochon 10 might also be given a different form from the spherical cap; for instance, it might be conical or cylindrical; the latter shape is the most appropriate for the purpose because it ensures better holding of the crown 4.

Claims

1. Watch-case, characterized by the fact that it comprises -a caseband having an annular portion delimiting an inner volume for housing a movement and having an upper side made to take a glass and a lower side made to take a caseback, a radial orifice in the said annular portion for permitting the passage of a stem carrying at one of its extremities a crown able to turn together with the stem round an axis of rotation and a groove formed in the said annular portion and presenting a lateral opening round the said radial orifice; and -a bridge, situated at the place of the said opening of the groove and passing above the said crown, solid with a means of attachment provided with a notch to allow the said stem to pass, the said means of attachment having a shape which enables it to enter the said groove of the caseback.

2. Watch-case in accordance with claim 1, characterized by the fact that the said groove and the said means of attachment have an annular shape.

3. Watch-case in accordance with claim 1 or 2, characterized by the fact that the said means of attachment is held in the said groove by the said caseback.

4. Watch-case in accordance wich claim 1 or 2, characterized by the fact that the said caseband and the said bridge with the said means of attachment are made of different materials.

5. Watch-case in accordance with claim 1 or 2, characterized by the fact that the surface of the said caseband and the surface of the said bridge and of the said means of attachment present different aspects at the visible points.

6. Watch-case in accordance with claim 1, characterized by the fact that the said radial orifice is provided with a water-resisting device.

7. Watch-case in accordance with claim 6, characterized by the fact that the said waterresisting device comprises a pipe driven into the said radial orifice and, together with the said crown, forming a water-resistant joint.

8. Watch-case in accordance with claim 1, characterized by the fact that the inner part of the said bridge facing the said notch is at least partly tangent to one side of a surface of revolution, the axis of which is identical with the said axis of rotation, and that one end of the said crown is at least partly tangent to the other side of that same surface of revolution.

9. Watch-case in accordance with claim 8, characterized by the fact that the said surface of revolution has the form of a spherical cap.

10. Watch-case substantially as described with reference to Figs. 3a-3c, Figs. 4a-4c, Figs. 5a-5c or Figs. 6a and 6b of the accompanying drawings.