Watch case comprising a bottom oriented in a predetermined angular position, watch comprising said case and method for assembling such a case

Abstract

The present invention relates to a watch case (100) comprising a case body (110) having a first opening receiving a crystal (120), opposed to a second opening receiving a case back (130), the watch case (100) being characterized in that the case back (130) is held in contact with an annular bearing surface (112) of the case body (110) by a threaded ring (140) cooperating by screwing with said case body (110), the case back (130) comprising a first indexing means (133) configured to cooperate with a second indexing means (114) with which the case body (110) is provided so as to immobilize said case back (130) in rotation according to a single angular position relative to the case body (110).

Description

Technical field of the invention

[0001] The invention falls within the field of watchmaking, and in particular the components of a watch case.

[0002] More particularly, the invention relates to a watch case having a back oriented in a predefined angular position, a watch comprising said case and a method of assembling such a case. Technological background

[0003] Watch cases consist of a case on either side of which are arranged a crystal and a back.

[0004] The case back is generally fixed to the case by screwing, and for this purpose has a thread intended to cooperate with a tapped hole made in the case.

[0005] This type of fixing does not allow control of the orientation of the case back in relation to the case, and in particular in relation to a vertical axis 12 o'clock - 6 o'clock, when they are fixed to each other.

[0006] Such a drawback is particularly detrimental for aesthetic reasons and perceived quality, when the background includes decorative elements or inscriptions.

[0007] The solutions developed using the state of the art are generally complex and expensive to implement.

[0008] Specifically, it is known to machine a tapped hole in the case and a thread on the case back in a particular way so that they are aligned, ensuring that when the case back is attached to the case, its angular position is known and always identical. However, in practice, this solution presents difficulties both in the manufacturing process and in after-sales service, for example, if it becomes necessary to replace a case back that may be lost or damaged.

[0009] Document US2010142332A1 discloses a wristwatch in which a case back is screwed onto a case in which a watch movement is housed. Summary of the invention

[0010] The invention solves the aforementioned drawbacks by proposing a solution allowing a base to be fixed to a case in a single predefined relative angular position.

[0011] To this end, the present invention relates to a watch case comprising a case having a first opening receiving a crystal, opposed to a second opening receiving a case back, the case back is held in contact against an annular bearing surface of the case by a threaded ring cooperating by screwing with said case, the case back comprising a single first indexing means configured to cooperate with a single second indexing means with which the case is provided so as to immobilize said case back in rotation according to a single angular position relative to the case, the latter comprising a tapped hole with which an external thread with which the ring is provided cooperates by screwing.

[0012] Thanks to these features, the case back does not require adjustment of its angular positioning relative to the case after being fixed to the case, as it is locked in rotation in a single predefined position.

[0013] The present invention also makes it possible to control the tightening torque of the base, and in particular of the ring, since when screwing the ring onto the case, the base is oriented in the predefined position.

[0014] The orientation of the fund is achieved with great precision thanks to the cooperation between the first and second indexing means, the said indexing means playing a role of error-proofing insofar as they allow the fund to be immobilized in a single position.

[0015] This feature also guarantees simplicity in the production and assembly of the watch case, which helps to reduce the manufacturing costs of watches including this case.

[0016] It is understood from the features of the present invention that the first and second indexing means block the rotational mobility of the bottom and that the ring blocks the translational mobility of the bottom.

[0017] In particular embodiments, the invention may further comprise one or more of the following features, taken individually or in all technically possible combinations.

[0018] In particular embodiments, the first and second indexing means are formed by a lug / notch pair.

[0019] According to the invention, the case includes a tapped hole with which an external thread of which the ring is provided cooperates by screwing.

[0020] In particular embodiments, the case back has a peripheral lip extending radially around the periphery of said case back, and is arranged to rest against the annular bearing surface of the case.

[0021] In particular embodiments, the ring comprises an annular portion including the external thread and an end surface by which it bears against the peripheral lip of the bottom.

[0022] In particular embodiments, the peripheral lip extends from a tubular wall forming an upper end of the bottom, the tubular wall being engaged in a bore of the case.

[0023] In particular embodiments, the notch is arranged on the tubular wall and extends axially from a free end of said tubular wall, said notch being configured to cooperate with the lug, said lug being arranged on the bore.

[0024] In particular embodiments, a joint is arranged between the case and the base, and is interposed between a shoulder formed by the junction between the tubular wall and the peripheral lip, and an annular recess of the case formed at the junction between the annular bearing surface and the bore.

[0025] In particular embodiments, the ring comprises a radial portion connected to the annular portion and having an internal radial surface arranged opposite an annular bearing surface of the base.

[0026] In particular embodiments, the radial portion of the ring comprises a lower cylindrical surface opposite which is arranged a lower cylindrical surface of the base of complementary shape.

[0027] According to another object, the present invention relates to a watch comprising a watch movement housed in an internal volume of a watch case as described above, said internal volume being defined between the case middle, the crystal and the back.

[0028] According to yet another object, the present invention relates to a method of mounting a watch case as described above, in which the case back is engaged in the second opening of the case so that the first indexing means cooperates with the second indexing means, and then the ring is screwed to the case so as to immobilize said case back in rest against said case. Brief description of the figures

[0029] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings in which: there figure 1 represents a cross-sectional view of a watch comprising a case according to a preferred embodiment of the invention: the figure 2 represents an exploded perspective view from above of the box of the figure 1on which a single primary indexing method available to the fund is visible; the figure 3 represents an exploded perspective view from below of the box of the figure 1 on which a single second means of indexing with which the case is equipped is visible. Detailed description of the invention

[0030] There figure 1 represents a cross-sectional view of a watch 10 comprising a watch case 100 according to the present invention.

[0031] The case 100 has a case 110 having a first opening receiving a glass 120, opposite a second opening receiving a back 130; the glass 120, the back 130 and the case 110 defining a volume inside which a watch movement is arranged in a way known to the person skilled in the art.

[0032] Since the watch movement and other watch components used in a case 100 are known to a person skilled in the art and are not part of the present invention, they are not described below.

[0033] The box 100 has a ring 140 adapted to be fixed to the case 110 while keeping the bottom 130 in position against the latter.

[0034] The ring has a central through-hole through which the base is visible, as shown in the figures 1 to 3 .

[0035] It should be noted that the case back 130, the ring 140 and the case middle 110 exhibit geometric shapes of revolution, whose axes of revolution are coaxial, as visible on the figures 2 And 3 .

[0036] The ring 140 has an external thread 141 by which it is intended to cooperate by screwing with a tapped hole 111 made in the case 110, at the level of the second opening.

[0037] Even more specifically, in the preferred embodiment of the present invention, the ring 140 has, at one of its ends called "upper end", an axial annular portion defined by an end surface 142 connecting an upper cylindrical surface 143 and an external surface, the external thread 141 being made on the external surface of the annular portion.

[0038] The terms "upper" and "lower" in this text refer to the spatial orientation of a 100 case as represented by the figures 1 to 3 , the ice 120 being arranged above the bottom 130.

[0039] Furthermore, the bottom 130 has a peripheral lip 131 extending radially around the periphery of the bottom 130, from a tubular wall 132 forming an upper end of said bottom 130, said peripheral lip 131 being arranged to rest against an annular bearing surface 112 of the case 110. Moreover, the tubular wall 132 is engaged in a bore 113 of the case 110 when the bottom is fixed to said case 110.

[0040] Alternatively, the bottom 130 may include a plurality of peripheral lips (not illustrated in the figures) extending radially each around a portion of the periphery of the bottom 130, in the same plane.

[0041] As shown in the cross-sectional view of the figure 1 , the ring 140 is configured so as to bear against the peripheral lip 131 of the bottom 130 by the end surface 142 of the annular portion, when said ring 140 is screwed with the case 110.

[0042] Advantageously, the bottom 130 includes a single first indexing means configured to cooperate with a single second indexing means with which the case 110 is equipped, so as to immobilize said bottom 130 according to a single angular position relative to the case 110 when the ring 140 fixes the bottom 130 against said case 110.

[0043] More specifically, the first and second indexing methods are formed by a lug / notch pair.

[0044] In the example implementation shown on the figures 2 And 3 , the bottom 130 is provided with a notch 133 arranged on the tubular wall 132, said notch extending axially from a free end of said tubular wall 132.

[0045] The notch 133 is intended to cooperate with a lug 114 extending inside the case 110. More particularly, the lug 114 is arranged on the bore 113 and has a shape complementary to that of the notch 133, except for mechanical clearances, so as to be able to engage inside the notch 133 when the tubular wall 132 of the bottom 130 is introduced into the bore 113.

[0046] It should be noted that in other embodiments of the invention not shown in the figures, the notch 133 can be arranged in the case 110 and the lug 114 can be arranged on the base 130, in a manner analogous to the preferred embodiment shown in the figures.

[0047] The ring 140 has a radial portion having an internal radial surface 144 intended to be arranged opposite an annular bearing surface 134 of the base 130, when the ring 140 is screwed into the threaded hole 111 of the case 110. The radial portion is connected to the annular portion, as shown in the figure 1 .

[0048] Advantageously, the fixing ring 140 can optionally bear against the peripheral annular bearing surface 134 of the bottom 130 in addition to bearing against the peripheral lip 131.

[0049] This annular bearing surface 134 is connected to the peripheral lip 131 by an upper cylindrical surface 135 intended to be arranged opposite the upper cylindrical surface 143 of the annular portion of the ring 140, when the base 130 is fixed to the case 110.

[0050] Furthermore, a joint 150 is arranged between the case 110 and the base 130, and is interposed between a shoulder formed by the junction between the tubular wall 132 and the peripheral lip 131, and an annular recess of the case 110 formed at the junction between the annular bearing surface 112 and the bore 113.

[0051] The radial portion of the ring 140 has a lower cylindrical surface 145 opposite which is arranged a lower cylindrical surface 136 of the bottom 130 of complementary shape.

[0052] When fixing the bottom 130 onto the case 110, the bottom 130 is first engaged in the second opening of the case 110 so that the lug 114 cooperates with the notch 133, the tubular wall 132 of the bottom 130 being engaged in the bore 113 of the case 110 until the peripheral lip 131 is arranged to bear against the annular bearing surface 112.

[0053] The base 130 and the case 110 then form a defined housing between the upper cylindrical surface 135, the peripheral lip 131 and the thread 111 of the case 110, in which the ring 140 is intended to be engaged.

[0054] The ring 140 is then brought to cooperate with the thread 111 of the case 110, until the peripheral lip 131 is pressed against the annular bearing surface 112 and a predetermined tightening torque is reached sufficient to rigidly fix, i.e. according to a mechanical connection of the type of embedding, the base 130, the ring 140 and the case 110 together.

[0055] Advantageously, the ring 140 may have a fillet or chamfer at the junction between the upper cylindrical surface 143 of the annular portion and the end surface 142, and the bottom 130 may also have a fillet or chamfer at the junction between the annular bearing surface 134 and the upper cylindrical surface 135, so as to facilitate the introduction of the ring 140 into the housing formed between the bottom 130 and the case 110.

[0056] In addition, a chamfer or fillet can be made at the junction between the cylindrical surface of the radial portion of the ring 140 and the internal radial surface 144 of said radial portion.

[0057] Preferably, the ring 140 has, on an external face opposite the internal volume of the watch case 100, radial notches 146 designed to cooperate with a tool operated by a user. Thanks to the radial notches 146, the ring 140 can be screwed or unscrewed by manipulating the tool, so as to fix the ring 140 and the case back 130 to the case middle 110, or conversely, so as to detach them from said case middle 110.

Claims

1. A watch case (100) comprising a middle (110) comprising a first opening for holding a glass (120), opposite a second opening for holding a back (130), in which the back (130) is held against an annular shoulder (112) of the middle (110) by a threaded ring (140) screwed into the middle (110), the back (130) comprising a single first indexing means (133) configured to engage with a single second indexing means (114) provided on the case (110) to rotationally immobilise said back (130) in a single angular position relative to the case (110), characterised in that the middle (110) comprises a tapping (111) with which an outer thread (141) provided on the ring (140) engages by screwing.

2. The watch case (100) according to claim 1, in which the first and second indexing means are formed by a catch / notch (114, 133) coupling.

3. The watch case (100) according to any of claims 1 to 2, in which the back (130) has a peripheral lip (131) extending radially around the periphery of said back (130), and being arranged to rest on the annular shoulder (112) of the middle (110).

4. The watch case (100) according to claim 3, in which the ring (140) comprises an annular portion comprising the external thread (141) and an end surface (142) by which it bears against the peripheral lip (131) of the back (130).

5. The watch case (100) according to claim 3 or 4, in which the peripheral lip (131) extends from a tubular wall (132) forming an upper end of the back (130), the tubular wall (132) being engaged in a bore (113) in the middle (110).

6. The watch case (100) according to claims 2 and 5, in which the notch (133) is formed on the tubular wall (132) and extends axially from a free end of said tubular wall (132), said notch (133) being configured to engage with the catch (114), said catch (114) being arranged on the bore (113).

7. The watch case (100) according to claim 5, in which a joint (150) is arranged between the middle (110) and the back (130), and is inserted between a shoulder formed by the junction between the tubular wall (132) and the peripheral lip (131), and an annular recess in the middle (110) formed at the junction between the annular shoulder (112) and the bore (113).

8. The watch case (100) according to claim 4, in which the ring (140) comprises a radial portion connected to the annular portion and having an inner radial surface (144) arranged opposite an annular shoulder (134) of the back (130).

9. The watch case (100) according to claim 8, in which the radial portion of the ring (140) comprises a lower cylindrical surface (145) facing which is arranged a lower cylindrical surface (136) of the back (130) with a matching shape.

10. A watch (10), characterised in that it comprises a horological movement turned in an inner volume of a watch case (100) according to any of claims 1 to 9, said inner volume being defined between the middle (110), the glass (120) and the back (130).

11. A method for fitting a watch case (100) according to any of claims 1 to 9, in which the back (130) is inserted into the second opening in the middle (110) such that the first indexing means (133) engages with the second indexing means (114), then the ring (140) is screwed into the middle (110) to immobilise said back (130) against said middle (110).

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