EP0465988B1 - Device for fastening a dial foot of a time piece - Google Patents

Abstract

The device for fastening the foot (6) of a dial (5) to the bottom plate (4) employs a post (1) comprising a first zone having a cylindrical rod (2) engaged in the bottom plate and a second zone in the form of a collar piece (3) which bears under the bottom plate. The rod (2) is held in the bottom plate by means of riveting (9). The collar piece has a thinned edge (10) capable of being deformed elastically. The thinned edge (10) extends beyond the drill hole (7) in which the foot (6) is engaged so that, in order to fasten the dial to the bottom plate, it suffices to insert the feet in the respective drill holes and to press on the dial until it is brought to bear on the bottom plate. The tilting (11) of the thinned edge along the foot holds the latter firmly in place. <IMAGE>

Description

The present invention relates to a device for fixing a dial base to the plate of a clockwork movement, the foot being engaged in a first drilling of the plate, the device comprising means made of metal, the edge of which is made to ensure a first locking of the foot in the first bore by rolling up said edge along the foot.

Such a fixing device is described in the document "RESEARCH DISCLOSURE", NO. 127, NOVEMBER 1974, EBAUCHES S.A. and entitled "Fixing the dial of a timepiece". In this prior solution (and in particular in FIG. 3 of the document), a metal grid overmolded with plastic material is used, the assembly constituting the plate of the watch movement. A fully metallic plate could only have spring blades if these blades were manufactured separately and assembled in place by hand in receptacles, the realization of which would be extremely difficult to envisage. The cost of such a solution would be very high. Furthermore, machining the blades in the body of the plate itself would be impractical.

It would obviously be desirable for the manufacturer of watch movements to be able to have a universal solution for fixing the dial, a solution which must be applicable to all the movements it manufactures, whether the movement plate is made of metal or made of from an overmolded grid.

However, to be able to have a sufficient length allowing operational operation, the spring blades must be cantilevered in the opening made in the plate. Thus, this anterior fixing device must have a length which would cause the manufacturer to place it very inside the movement to be able to take into account the curved periphery of the plate.

In order to be able to use the known device, it would therefore have to be brought back radially towards the inside of the plate. But then, it would encroach on the space of the movement in which the calendar ring is located, if the movement is provided with a calendar indicator. As a result, the known device could not be used for any movement so that the manufacturer who used it should have specific dial fixings for its movements provided with a date indicator.

Furthermore, with the fixing device of the prior art, it would hardly be possible to redo an assembly operation of a dial, in other words to carry out a repair on a movement requiring the disassembly of the dial, because during the first disassembly, the spring blades would be completely deformed by the removal of the feet from the dial. However, it would be desirable to be able to carry out a second, even a third assembly.

The object of the invention is to remedy the drawbacks of the prior art analyzed above and to provide an improved device for fixing a dial base of the type defined in the preamble to this specification, but which is devoid of these drawbacks.

The subject of the invention is therefore a device for fixing a dial base which is characterized in that said means made of metal comprise a lug having a first zone in the form of a cylindrical rod engaged in a second bore made in the plate, the end of the rod comprising retaining means to prevent it from moving axially and a second zone having a collar at least partially surrounding the rod by resting under the plate, the post being metallic and the collar having less on a part of its periphery, a thinned edge whose thickness is chosen to allow a deformation by rolling up when the engagement of the dial base in said first hole of the plate, while said tenon is retained in said second hole by said retaining means.

Thanks to these characteristics, the implementation of the improved fixing device is very simple since it suffices, without having to angularly orient the tenon, to force the dial feet into their seat until the dial abuts on the plate. This operation requires no tools.

Furthermore, the fixing device requires very little space at the extreme edge of the plate so that it can be used with watch movements of all kinds, including those comprising a date ring.

In patent CH-A-77 267, a dial base is described comprising a flange whose edge is in the form of a spiral and which cuts into the base of the dial when it is put in place by rotation of the tenon around of its axis. To do this, it is essential that the edge of the collar is as rigid as possible in order to precisely be able to cut the dial foot and thus retain it after the rotation of the stud. It appears, on the contrary, that if the edge of the collar was deformable (for example by rolling up), a notch in the dial foot could not occur.

Observations equivalent to those made in relation to patent CH-A-77 267 can be made in connection with patent US-A-3 523 417. Here too, the dial key operates exclusively by incision and has a flange which must be sufficiently rigid to allow such an incision.

In patent FR-A-577 824, it is a screwed dial key also operating by incision. This is an expensive and complicated solution to implement because the key must be tightened by rotating it over several turns.

Document CH-D-6413/71 recommends an even more expensive solution, since it requires an oblique hole in the plate. To do this, it must be specially taken up by a particular machining operation. In addition, when setting up the dial, it is not at all sure that things happen as shown in the figures in the document. It may very well be that the dial key rips along the dial base, making only partial contact with it.

In patent FR-A-2 324 036 (US-A-4 213 295), a fixing device for a dial base is described similar to that of patent US-A-3 523 417 for example, except that the flange of the post has a flat formed on a plane parallel to the axis of the post. The implementation of this device therefore also requires first of all to orient the dial key so that the flat of the stud is opposite the hole which will receive the base of the dial. It then requires reversing the movement to place the dial on the plate at the same time which feet in the corresponding holes. Once this operation is completed, it is a question of turning the movement a second time and turning the studs using a tool to penetrate their sharp edges into the dial feet. It will be understood that the device described requires a whole series of operations which take time, which also contributes to increasing the price of the timepiece.

Finally, patent CH-A-510 904 describes a fixing device in which a blocking member carried by the plate cooperates with the dial base by friction. To achieve this goal, the blocking member is constituted by a piece of slightly compressible plastic material projecting under the plate and having the shape of a trunk of cone whose small base is located flush with platinum. During installation, part of the truncated cone is thus deformed. This device uses a complicated part to produce and ultimately leads to an insufficient result as regards the holding of the dial, the feet cannot be fixed permanently.

• la figure 1 est une vue de côté d'un tenon permettant de mettre en oeuvre le dispositif de fixation selon l'invention et selon un premier mode d'exécution de ce tenon,
• la figure 2 est une vue d'ensemble du dispositif de fixation utilisant le tenon de la figure 1,
• la figure 3 est une variante du dispositif de fixation exécuté selon le premier mode d'exécution,
• la figure 4 est une vue de dessus d'un tenon permettant de mettre en oeuvre le dispositif de fixation selon l'invention et selon un second mode d'exécution de ce tenon,
• la figure 5 est une coupe partielle selon la ligne V-V de la figure 4,
• la figure 6 est une vue d'ensemble du dispositif de fixation utilisant le tenon des figures 4 et 5.
• la figure 7 est une variante du dispositif de fixation exécuté selon le second mode d'exécution, le tenon étant vu de dessus, et
• la figure 8 est une vue en élévation du tenon représenté à la figure 7.

The invention will now be explained by means of the following description, illustrated by way of example by the drawing which presents several embodiments, a drawing in which:

• FIG. 1 is a side view of a post making it possible to use the fixing device according to the invention and according to a first embodiment of this post,
• FIG. 2 is an overall view of the fixing device using the pin of FIG. 1,
• FIG. 3 is a variant of the fixing device executed according to the first embodiment,
• FIG. 4 is a top view of a post making it possible to use the fixing device according to the invention and according to a second embodiment of this post,
• FIG. 5 is a partial section along the line VV in FIG. 4,
• FIG. 6 is an overall view of the fixing device using the tenon of FIGS. 4 and 5.
• FIG. 7 is a variant of the fixing device executed according to the second embodiment, the tenon being seen from above, and
• FIG. 8 is an elevation view of the post shown in FIG. 7.

Figure 1 shows a stud 1 before mounting on the plate and used to constitute a first embodiment of the device fixing according to the invention. This post has a first zone 2 in the form of a cylindrical rod and a second zone 3 having a collar coaxial with the rod.

FIG. 2 is an overall view of the fixing device according to the invention, device using the lug 1 of FIG. 1. FIG. 2 shows the plate 4 of the timepiece, plate surmounted by a dial 5. To this dial are fixed, in the usual way, feet of which only one 6 appears in the figure. The foot 6 is engaged in a first bore 7 of the plate 4. The cylindrical rod 2 of the post 1 is engaged in a second shape 8 formed in the plate. The end of the rod 2 comprises retaining means 9 to prevent this rod from moving axially. It can be a simple riveting here. FIG. 2 also shows that the collar 3 rests under the plate 4. FIGS. 1 and 2 show that the collar has on its periphery a thinned edge 10, this edge ensuring a first locking of the foot 6 in the bore 7 by a rolling up 11 of this edge 10 along the foot 6. It goes without saying that the distance which separates the axes of the holes 7 and 8 is arranged so that the thinned edge 10 of the collar 3 encroaches on the hole 7 receiving the foot of the dial . Thus, when the foot 6 is introduced into the bore 7, the thinned edge 10 of the flange 3 is rolled back down. As the rod 2 of the tenon is retained by the riveting 9, there can only be rolling up of the edge 10. As the collar is made of metal and preferably of elastically deformable metal, the foot 6 is firmly retained in its bore and can no longer escape from it, the upturned edge 11 making a notch in the material of the foot 6, this material being copper in most cases, but may also be synthetic material.

The thinned edge 10 of the collar 3 can be produced in different ways. As we will manufacture the post 1 preferably by turning, it is convenient to give the flange the shape of a truncated cone whose large base 12 rests under the plate 4. The fact that it is the large base 12 which supports under the plate and not the small base 13 gives the post a good seat and prevents any limping in its bore 8, which contributes to better binding of the upturn 11 on the foot 6.

We understand the simplicity of the implementation of the fixing device since it is enough, once the post 1 installed without any search for angular orientation, to force the dial feet in their seat until the dial abuts on plate 4. This operation requires no tools. The dial is then fixed in a single operation which is the operation of introducing the feet each into its respective bore, the tenon 1 not having to be turned as was the case of the device described above with respect to the document FR-A-2 324 036.

Figure 3 shows a variant of the first embodiment described above. In this variant, the post 1 further comprises a third zone 14 situated in extension of the flange 3. This third zone has a slot 15 suitable for receiving a tool, a screwdriver for example, which will allow the rotation of the post to ensure a second locking of the foot 6 in the borehole 7. It may indeed be desired to ensure even better blocking of the foot, in which case the tenon will be turned by means of the cited tool, which will further reinforce the binding of the upturned edge 11 on the foot of dial.

The first embodiment of the invention and the variant which is linked to it, preferably provides a thinned rim 10 over the entire periphery of the flange 3 to avoid any orientation to be given to the post during its installation. If the dial were to be removed, the feet 6 would be driven out of the holes 7. If the upturned edge were to be damaged by this operation, it would then suffice to turn the tenon a few tens of degrees so that it presents, facing the foot of dial, a thinned edge in good condition.

Reference will now be made to FIGS. 4 to 6 to explain a second embodiment of the invention.

Figure 4 is a top view of a stud 21 for implementing the fixing device according to this second embodiment. If we also consider Figure 5 which is a partial section along the line VV of Figure 4, we see that this stud has, before mounting on the plate and as in the previous embodiment, a first area 22 in shape of cylindrical rod, a second zone 23 having a collar coaxial with the rod and a third zone 214 located in extension of the collar, this third zone having a slot 215 suitable for receive a tool allowing the rotation of said post. Originally, the flange 23 has a peripheral edge according to the profile shown in dotted lines and referenced 20. This edge has a cutting and rigid character. The thinned edge 210 of this tenon is obtained by stamping a portion of the cutting edge 20 in a region delimited by the wall 16, this stamping not only resulting in the thinning of the profile 20 but also an elongation 17 of the thinned edge 210 in the direction opposite the axis of the post.

As for the tenon of the previous embodiment, this new tenon 21 is introduced by its rod 22 into a second bore 28 of the plate 24 as is apparent in FIG. 6. The end of the rod 22 also includes means for retainer 29 to prevent this rod from moving axially. Figure 6 also shows that the flange 23 of the post 21 is supported under the plate 24. In this embodiment, care will be taken to orient the post as shown in Figure 6, that is to say with its thinned edge 210 directed towards the foot 26 of the dial 25. Thus when the foot 26 is introduced into the first bore 27 of the plate, the tapered edge 211 is rolled up 210 along the foot 26, which results in a first locking of the foot as this was explained above.

In most cases this first locking is sufficient to block the dial on the plate. In certain cases, however, it is desirable to ensure even better anchoring of the dial, that is to say an even more reliable second locking, particularly in the case where the movement is fixed to the watch case by means of the dial. This can be achieved by means of the pin 21 by imparting to it a rotational movement for example in the direction of the arrow A (FIG. 4), at an angle situated approximately between 60 and 90 degrees. At this time, the cutting and rigid edge 20 of the flange 23 cuts into the dial foot 26 which has been shown in dotted lines in FIG. 4. It will be noted that, since the thinned edge 210 has been obtained by stamping of only one portion of the periphery of the flange 23, there are sharp and rigid edges on either side of the thinned edge so that the pin of this embodiment can be turned either right or left to obtain the second locking.

Figures 4 to 6 also show that the flange 23 has a flat 18 formed on a plane parallel to the axis of the stud 21 and that this flat is diametrically opposite the thinned edge 210. This flat is useful for clearing the dial base. Indeed, in the case where the dial is to be removed, the tenons 21 are turned until the plates 18 are opposite the feet 26.

Figures 7 and 8 show a variant of the post described in connection with Figures 4 and 5. This new post 41 also has a first zone 42 in the form of a cylindrical rod, a second zone having a flange 43, the axis 47 of the flange 43 being offset relative to the axis 48 of the rod 42, and a third zone 45 situated in extension of the collar, this third zone having a slot 46 capable of receiving a tool making it possible to drive the tenon in rotation. Figures 7 and 8 show that the collar 43 has a thinned edge 44 located in a range defined by the sector a. This thinned edge is capable of ensuring a first locking of the foot 26 (shown here in dotted lines) in its bore 57, this by the rolling up which has already been mentioned above. The collar 43 further comprises two second rigid and cutting edges 49 located on either side of the thinned edge 44. One or the other of these second edges are caused to cut the foot 26 depending on whether the tenon is turned in one direction or the other, if it is necessary to ensure a second more solid locking (see above). These rigid and cutting edges are located in the ranges delimited by sectors b. The figures finally show a third edge 50 diametrically opposed to the thinned edge 44. This third edge is located behind the first bore 57 in a range delimited by sector c. Thus, when one wants to release the foot 26, the tenon 41 is turned until the sector c is opposite the foot.

Compared to the second embodiment of the invention, the variant which has just been presented is very advantageous since it eliminates two operations, namely the stamping of the thinned edge and the milling of the edge opposite said thinned edge. In this variant the tenon is produced by turning. To make the post, we start from a bar whose diameter is equal to the diameter of the flange 43, the axis 47 of the bar being eccentric relative to the axis 48 of turning, this axis being coincident with the axis of the cylindrical rod 42 of the tenon 41. This way of proceeding makes it possible to immediately obtain the flange as it appears in FIG. 8. The sectors a, b and are not defined as frankly as in the previous embodiment since the thickness of the flange increases continuously from sector a to sector c. However, experience has shown that this variant gives results at least as good as those obtained by the second embodiment described above and this at lower cost.

It will be mentioned that the device of the invention, in addition to the advantages already listed above, can be used on all turntables where the dial feet are retained by keys in common use, the system recommended by the invention therefore being able to advantageously replace other more complicated systems without particular modifications to the watch movement.

It will also be observed that the dial foot used to produce the fixing device is cylindrical over its entire length and that it therefore does not require any special preparation.

The post will preferably be made of stainless material, this material preferably having elastic deformation qualities so as to ensure a constant pressing force of this edge against the foot.

Claims (10)

1. Device for fastening a dial foot (6, 26) to the base plate (4, 24) of a timepiece movement, the foot being fitted into a first borehole (7, 27, 57) of the base plate, the device including means (1, 21, 41) made of metal, the edge (10, 210, 44) of which is fashioned to assure a first locking of the foot (6, 26) in the first borehole (7, 27, 57) by upsetting said edge along said foot, characterized in that said means include a stud (1, 21, 41) exhibiting a first zone in the form of a cylindrical stem (2, 22, 42) fitted into a second borehole (8, 28) formed in the base plate, the end of the stem comprising retaining means (9, 29) for preventing it from being axially displaced, and a second zone exhibiting a collar (3, 23, 43) surrounding the stem at least partially in bearing under the base plate, in that the stud is metallic and in that the collar exhibits a thinned-down edge (10, 210, 44), at least over a portion of its periphery, the thickness of which is chosen to permit a deformation by upsetting when the dial foot is engaged in said first borehole of the base plate, while said stud is retained in said second borehole by said retaining means.
2. Fastening device according to claim 1, characterized by the fact that the collar (3) is coaxial with the stem and exhibits the form of a cone frustum the wider base (12) of which rests under the base plate (4), a portion (11) of said wider base being upset in the direction of the lower part of the base plate or encroaching on the first borehole (7) according to whether said foot (6) is or is not in place in said first borehole.
3. Fastening device according to claim 1, characterized by the fact that the stud (1, 21, 41) includes moreover a third zone (14, 214, 45) located in the extension of the collar (3, 23, 43), said third zone exhibiting a slot (15, 215, 46) adapted to receive a tool permitting rotation of said stud in order to assure a second locking of said foot (6, 26) in said first borehole (7, 27, 57).
4. Fastening device according to claim 3, characterized by the fact that the collar (23) is coaxial with the stem and exhibits, in addition to a first thinned-down edge (210) adapted to assure a first locking of the foot (26) in the first borehole (27), at least one cutting and rigid second edge (20) encroaching on said first borehole in order to assure a second locking of said foot when one imparts a rotational movement to the stud (21) in order to bring said cutting and rigid second edge to notch said foot.
5. Fastening device according to claim 4, characterized by the fact that the collar (23) includes two cutting and rigid edges (20) located on either side of said thinned-down edge (210).
6. Fastening device according to claim 5, characterized by the fact that the collar (23) exhibits a flat (18) formed along a plane parallel to the axis of the stud (21), said flat being diametrically opposite the thinned-down edge (210) and, when brought by rotation opposite the foot (26), permitting disengagement of such latter from said stud.
7. Fastening device according to claim 5, characterized by the fact that the thinned-down edge (210) is obtained by die stamping of a portion of the cutting and rigid edge (20).
8. Fastening device according to claim 3, characterized by the fact that the collar (43) exhibits an axis (47) which is offset relative to the axis (48) exhibited by the stem (42), said collar exhibiting successively, in addition to a first thinned-down edge (44, a) adapted to assure a first locking of the foot (26) in the first borehole (57) by upsetting said edge along said foot, two second cutting and rigid edges (49, b) located on either side of said thinned-down edge and encroaching on said first borehole so as to assure a second locking of said foot when one imparts a rotational movement to the stud (41) in order to bring one or the other second cutting and rigid edge to notch said foot and a third edge (50, c) diametrically opposite to the first thinned-down edge and in location offset from said first borehole in order to free said stud when said third edge is brought opposite said foot by rotation.
9. Fastening device according to claim 8, characterized by the fact that the stud (41) is obtained by turning a cylindrical bar the diameter of which is equal to the diameter of the collar (43), the axis (47) of the bar being offset relative to the turning axis (48).
10. Fastening device according to any of claims 1 to 9, characterized by the fact that the stud (1, 21) is formed of elastically deformable metal.

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