HK1036112B - Timepiece including a movement mounted in a casing ring - Google Patents

Description

Timepiece including a movement mounted in a casing ring

Technical Field

The invention relates to a timepiece comprising a case provided with a back cover and a middle part, and a case ring for housing a movement equipped with hands moving over a dial, the case ring extending substantially the entire height of the middle part in which it is housed.

Background

Assembling a watch typically involves the following sequential steps. First, the movement is introduced into the shell ring by orienting the two parts so that, if the parts are circular, the raised portion of the shell ring penetrates into the recess of the movement. Next, a dial is placed on the case ring. When the dial is pressed onto the case ring, the latter is finally fixed, for example by ultrasonic welding. The hands of the movement are then set in position. The shell ring is then introduced through the top of the shell and slid until it abuts the back cover of the shell. The movement also comprises a time setting shaft on which a crown is mounted. The time-setting spindle ensures the angular positioning of the ring with respect to the middle when the watch is assembled, in which case the middle and the ring have a circular configuration. It will be appreciated that in this case the holes formed in the middle and shell rings respectively must be aligned to allow the time-setting shaft to pass through. The watch also comprises a crystal bezel mounted above the dial and fixed to the case by means of a bezel engaged in a notch in the upper circumference of the middle part.

The assembly method just described has the drawback that it is difficult to guarantee a determined and precise height position of the movement with respect to the case, due to the inherent play of the dimensional tolerances of the dial, the case ring and the back cover of the case. In certain cases, the vertical play of the shell ring with respect to the shell can be compensated for by the pressure exerted by the glass frame, under which action the ring tends to deform elastically. However, this occurs at the expense of a constant reaction force of the ring against the crystal face glass, which is then liable to be damaged or to slip out of the middle.

To overcome this drawback, and to allow a more precise height positioning of the shell ring with respect to the casing, it has been proposed to provide the ring with means capable of plastic deformation to remove the full size gap. An embodiment of such a ring is shown in figures 1 and 2, which are attached to the present patent application.

Referring to fig. 1, a cross-section of a timepiece, generally designated 1, is seen. The timepiece 1 comprises a movement 2 mounted in a casing ring 4, a dial 6 mounted above the casing ring 4 and a crystal 8 mounted above the dial 6. The shell ring is mounted in a housing 10 which contains a central portion 12 and a rear cover 14 which is integrally formed as a single piece with the central portion 12. The crystal face glass 8 rests on top of the central portion 12 and is held thereto by a glass frame 16 held in the indentation 18.

The means for positioning the ring 4 in height with respect to the housing 10 comprise a number of points 20, only one of which is shown in fig. 1. These conically shaped points 20 are arranged below the shell ring 4. They, for example 4, are arranged at equal distances from each other to ensure that the ring 4 sits well on the back cover 14. After setting the shell ring 4 in place on the housing 10, the latter is pushed. Under the effect of this pressure, the point 20 is pressed into plastic deformation against the rear cover 14 of the housing 10 until the shell ring 4 assumes a determined height position relative to the housing 10. At this point, the end of the taper 20, no longer being a point, but being convex, can be seen in FIG. 1, more precisely in FIG. 2, where FIG. 2 is a detailed view of FIG. 1.

It has been understood from the foregoing that the positioning device described above undergoes plastic deformation, which deformation results in irreversible extrusion of the material. Thus, when the shell ring is in place, it is not subjected to any vertical compressive forces, as it undergoes plastic deformation.

The solution just described, while being a sufficient improvement with respect to the state of the art when used, still reveals certain drawbacks. In particular, it has been found that the positioning device does not always allow the height of the shell ring relative to the middle to be adjusted as precisely as desired. It will be appreciated that it is difficult to closely control the crushing and deformation of the points through which the shell ring bears against the back cover of the housing. It has therefore been observed that, in certain cases, it is not possible to align the holes made in the central part and in the shell ring for the passage of the time-setting shaft in a suitable manner. Thus, the shaft is prone to jamming, which makes its operation difficult, or impossible.

Disclosure of Invention

The object of the present invention is to overcome the above-mentioned drawbacks of the prior art by providing a timepiece comprising a casing ring which can be positioned precisely inside the casing without exerting pressure in such a way as to make it possible to remove the crystal face glass from its casing.

The invention therefore relates to a timepiece comprising a case with a back and a middle part, a movement mounted in the case, a dial mounted on the case, and a crystal mounted on the dial, the crystal being provided with an annular flange surrounding the side of the dial, wherein the case comprises an elastically deformable flexible strip arranged to remove all the gaps inherent to the dimensional tolerances of the dial, the case and the back of the case, the flexible strip being arranged at the upper end of the case along the outer circumference of the case, wherein the flange of the crystal is supported on the flexible strip.

In a further aspect of the invention, raised portions are provided on the flexible strip, by means of which raised portions the flanges of the crystal surface glass are brought to bear against the flexible strip. When the crystal surface glass is mounted in the housing, the flange of the crystal surface glass is lowered to a plane slightly lower than the plane of the raised portion protruding above the flexible strip when the flexible strip is at rest. The raised portion is a protrusion. The number of said flexible strips is 3, which are arranged at 12 o ' clock, 5 o ' clock and 7 o ' clock, respectively, to ensure the correct fixation of the crystal cover glass.

By these features, a precise positioning of the movement with respect to the casing can be ensured. It is no longer necessary for the shell ring to be made of a material that undergoes plastic deformation, as is the case with the prior art shells. In this way the shell ring and the back cover of the housing can be machined with a high degree of precision, typically a few percent of a millimeter, suitable for good alignment of the through holes of the time-setting shaft, which holes are formed in the middle part and the shell ring. At the same time, any play due to dimensional tolerances of the different components (case ring, dial, case back) is eliminated by elastic deformation of the flexible strips arranged at the top end of the case ring, on which the crystal face glass flange is supported. The sum of the different tolerances is substantially less than the amount of deformation of the flexible strip, which is about two tenths to three of a millimeter. In this way, when the crystal face glass is placed over the shell ring and fixed thereto by the glass frame tucked into the cutout in the middle, it abuts against the narrow strip, which has the effect of pressing the shell ring against the rear cover of the housing. Thus, the casing ring and crystal face glass are always properly retained within the casing of the timepiece whether the gap is positive or negative.

Drawings

Other characteristics and advantages of the present invention will become clearer after reading the following detailed description of an embodiment of a timepiece according to the invention, given purely by way of illustration and not by way of limiting example, with reference to the accompanying drawings, in which:

figure 1 is a cross-section of a timepiece assembled according to a method of the prior art, which has already been cited;

fig. 2 is an enlarged view of the area enclosed by the chain line in fig. 1, which has been cited;

figure 3 is an overall cross-sectional view of the timepiece according to the invention;

FIG. 4 is an enlarged view of the area enclosed by the circle in FIG. 3;

figure 5 is a general perspective view showing the case ring housing a cartridge;

FIG. 6 is an exploded top perspective view of the assembly formed by the case ring, movement, dial and crystal face glass;

FIG. 7 is an exploded bottom perspective view of the same components as shown in FIG. 6;

FIG. 8 is a perspective view showing a crystal face glass placed on a shell ring and abutting via its flanges against flexible strips; and

fig. 9 is an enlarged view of the area surrounded by the circle in fig. 8.

Detailed Description

The present invention starts from the general inventive idea which consists in providing a flexible strip at the upper circumferential portion of the case ring to eliminate the clearance due to the dimensional tolerances of the case ring, the dial and the back cover of the case. The crystal face glass, pressed against the ring by the glass frame engaged in the notch of the middle, abuts elastically against these strips via an annular flange surrounding the side of the dial, and in turn presses the ring against the back cover of the case. It is therefore no longer necessary to provide means capable of deforming in an elastic or plastic manner inside the ring to eliminate the structural gaps as in the prior art. Therefore, the ring and the rear cover of the housing can be machined with high precision, so that the hole formed in the middle for the passage of the time-setting shaft and the ring can be properly aligned.

A timepiece according to the invention, generally designated by the reference numeral 22, is shown in cross-section in figure 3. It comprises a housing 24 having a central portion 26 and a rear cover 28, which in the example shown is made in one piece with the central portion 26. It goes without saying that the invention is equally applicable to a housing which is not one-piece and comprises a rear cover separate from the central part. Timepiece 22 also includes a movement 30 mounted in a casing ring 32, a dial 34 mounted on ring 32, and a crystal face glass 36 mounted over the dial. The crystal face glass 36 rests on means 38 for eliminating the play due to the dimensional tolerances of the ring 32, the dial 34 and the back cover 28 of the case 24, as will be described in detail hereinafter.

In particular, movement 30 is provided with a hour hand 40, a minute hand 42 and a second hand 44 which rotate between dial 34 and crystal face glass 36. The movement 30 also comprises a time-setting spindle 46 on which a crown 48 is fitted. The sealing of the shaft 46 with respect to the housing 24 is ensured by an O-ring gasket 50. The time setting shaft 46 ensures the angular positioning of the ring 32 relative to the middle portion 26 when the watch 22 is assembled, in which case the middle portion 26 and the ring 32 are circular. In fact, the holes 52 and 54 formed in the central portion 26 and in the ring 32, respectively, must be correctly aligned in order to allow the passage of the time-setting shaft. The housing 24 has a notch 56 in its upper circumference which engages a glass frame 58 which secures the crystal face glass 36 to the housing 24. The crystal facing 36 is sealed with respect to the housing 24 by the use of a sealing gasket 60 wedged between the crystal facing and the housing. Legs 62 are provided under the shell ring 32. These legs, for example six, can be arranged at regular intervals to each other. These legs 62 cannot deform and serve only to ensure that the ring 32 is properly retained on the back cover 28 of the housing 24.

Fig. 5 is a general perspective view showing the case ring 32 with the movement 30 mounted thereon. Fig. 6 and 7 are top and bottom views, respectively, of the ring 32, dial 34 and crystal face glass 36, shown in exploded perspective view.

In the preceding figures it can be seen that dial 34 and crystal face glass 36 are provided with means which cooperate together to angularly position and centre crystal face glass 36 relative to dial 34. The drawing shows that dial 34 has a side 64 from which three lugs 66 emerge that extend beyond the circumference of dial 34. As is evident in fig. 6 and 7, the dial glass 36 is provided with an annular shoulder 68 resting on the dial 34 and a flange 70 surrounding the side 64 of the dial 34. The flange 70 has three scallops 72 arranged to overlie the lugs 66. The three lugs 66 and the three scallops 72 that overlap the three lugs 66 are equally spaced from each other. The crystal face glass 36 can be angularly positioned and perfectly centered with respect to the dial 34.

Lug 66 also serves to fix and angularly position dial 34 relative to case ring 32. For this purpose, each lug 66 has a notch 74. These notches 74 are arranged so that each receives a respective stud 76 that projects above the top surface 78 of the shell ring 32. When dial 34 is pressed against ring 32, studs 76 of ring 32 penetrate respective indentations 74 of lugs 66 of dial 34. In order to accurately fix dial 34 to ring 32, pins 76 are hot pressed. Finally, the casing ring 32 has a projecting portion 80 which penetrates into the casing 82 of the movement 30 in order to position them with respect to each other when they have a circular configuration.

Fig. 5 to 9 clearly show that the means 38 for eliminating the clearance inherent in the dimensional tolerances of the ring 32, the dial 34 and the back cover 28 of the casing 24 according to the invention take the form of flexible strips 84 that are elastically deformable. In the example shown in the figure, there are three of these strips 84, set at 12 o ' clock, 5 o ' clock and 7 o ' clock respectively. It goes without saying that the number and arrangement of the strips 84 can be adjusted as desired without departing from the scope of the invention. The narrow strip 84 is disposed at the top end of the shell ring 32, along the outer circumference of the shell ring. Each strip 84 has a raised portion by which the flange 70 of the crystal face glass 36 rests on the strip 84. According to a preferred embodiment of the invention, the raised portion of the strip 84 is a projection 88. Due to these narrow strips 84, the housing ring 32 and the back cover 28 of the housing 24 can be machined with precise tolerances, typically on the order of a few percent of a millimeter, so that the through holes 52 and 54 formed in the middle portion 26 and the ring 32, respectively, through which the timing shaft 46 passes remain properly aligned and the shaft 46 is therefore not easily jammed.

It is important to understand that the sum of the tolerances of the different constituent elements of the timing member 22 according to the invention is significantly smaller than the deformation of the strip 84, which is of the order of a few tenths of a millimetre. Thus, whether the gap is positive or negative, it is eliminated so that the ring 32 and crystal face glass 36 remain properly seated against the back cover 28 of the housing 24. In fact, as shown in fig. 9, the crystal face glass 36 bears with its flanges 70 against the strips 84, thus generating a pressure that presses the ring 32 against the back cover 28 of the casing 24, wherein the crystal face glass is pressed against the ring 32 by the glass frame 58 inserted into the notches 56 of the casing 24, the flanges 70 having the effect of elastically deforming these strips 84 downwards. In the case that the flange 70 is lowered to a height position which is slightly lower than the height at which the tops of the projections 88 projecting from the strip 84 lie when the crystal surface 36 is mounted on the housing 24 when the flexible strip is at rest, the flange 70 of the crystal surface 36 is still obtained to bear against the flexible strip 84.

It goes without saying that various simple modifications and variations are included in the scope of the present invention.

Claims (8)

1. A timepiece comprising a casing (24) having a back cover (28) and a middle portion (26), a movement (30) mounted in a casing ring (32), a dial (34) mounted on the casing ring (32), and a crystal (36) mounted on the dial (34), the crystal face glass (36) is provided with an annular flange (70) surrounding the side face (64) of the dial (34), characterized in that said case ring (32) comprises flexible strips (38) capable of elastic deformation and arranged to eliminate all the gaps inherent to the dimensional tolerances of said dial (34), said case ring (32) and said back cover (28) of said case (24), the flexible strip (38) is arranged at the upper end of the housing ring (32) along the outer circumference (86) of the housing ring, wherein said flange (70) of said crystal face glass (36) is supported on said flexible strip.

2. Chronograph element according to claim 1, characterized in, that raised portions are provided on the flexible strip (84), by means of which raised portions the flanges (70) of the crystal face glass (36) rest on the flexible strip (84).

3. Chronograph piece according to claim 2, characterized in that when the crystal (36) is mounted in the casing (24), the flange (70) of the crystal (36) drops to a height slightly lower than the height at which the raised portions, which protrude on the flexible strips (84) when they are at rest.

4. Timepiece according to claim 2 or 3, wherein said protruding portion is a projection (88).

5. Chronograph element according to claim 1, characterized in that the number of said flexible strips (84) is 3, arranged at 12 o ' clock, 5 o ' clock and 7 o ' clock, respectively, to ensure the correct fixing of the crystal face glass (36).

6. Chronograph element according to claim 2, characterized in that the number of said flexible strips (84) is 3, arranged at 12 o ' clock, 5 o ' clock and 7 o ' clock, respectively, to ensure the correct fixing of the crystal face glass (36).

7. Chronograph element according to claim 3, characterized in that the number of said flexible strips (84) is 3, arranged at 12 o ' clock, 5 o ' clock and 7 o ' clock, respectively, to ensure the correct fixing of the crystal face glass (36).

8. Chronograph piece according to claim 4, characterized in that said flexible strips (84) are 3 and they are arranged at 12 o ' clock, 5 o ' clock and 7 o ' clock, respectively, to ensure the correct fixing of the crystal face glass (36).