WO2004088436A2 - Reversible watch - Google Patents

Abstract

The invention relates to a reversible watch consisting of a middle (1) comprising a first face (10) with a first time-indicating display and a second face (11) which is disposed opposite said first face. According to the invention, a turning mechanism (20, 21, 22, 23) is used to turn the middle (1) around a pivot axis (201-211; 221-231) which is parallel to the 6/12 axis of the watch, such that the wearer can choose to display the first face or the second face. The aforementioned turning mechanism comprises a pivot arm (20, 21; 22, 23) on each side of the middle, which can be used to move the pivot axis. Moreover, the middle (1) is connected to the arm (20, 21; 22, 23) in such a way that it can pivot around the pivot axis (201-211; 221-231). The above-mentioned arms are sufficiently long such that the middle can be turned over without the winding crown or any other buttons coming into contact with other parts (17) of the watch.

Description

 Reversible watch

The present invention relates to a reversible watch, and a method of turning a reversible watch case.

By reversible watch is meant a watch the case of which has two faces and a turning mechanism allowing the user to display either side as desired. At least one of the faces has a dial with time indications; the opposite face carries either another dial with other time indications, for example another time zone or additional functions, or a frequently decorated protective cover.

Reversible watches are thus known for example comprising two mechanical movements for displaying, for example, two time zones on the two faces of the watch, or for displaying the time on one face and auxiliary functions, for example chronograph functions, phases moon, date, etc. on the other phase. Integrating two mechanical movements in a single box is however expensive and requires significant thickness. Watches comprising a single mechanical movement capable of displaying indications on two opposite faces are also known; such movements, complex and often produced in limited quantities, are also expensive. There are also known watches comprising two head-to-tail quartz movements, but which do not have the advantages or the prestige of mechanical movements. These watches require in particular one, or even two separate batteries. Different reversal mechanisms have been devised. Watches are known, for example, in which the bracelet is turned over with the middle part, the inside face and the outside face of the strap and of the watch which can thus be inverted. This solution, however, requires bracelets and reversible bracelet clasps, the aesthetics of both sides of which is very careful.

Watches are also known in which the middle pivots around an axis 9 o'clock - 3 o'clock, that is to say an axis perpendicular to the bracelet. In this case, the turning mechanism occupies the space around the middle part usually assigned to the time-setting crown and to the other control members, which implies severe aesthetic constraints for watch manufacturers and designers.

The most common reversible watches therefore use a turning mechanism allowing the middle to be pivoted around an axis 6 o'clock - 12 o'clock in the plane of the bracelet. Patent application FR2716353 describes for example a watch in which each strand of the bracelet is connected to the middle part by means of a pivot making it possible to turn the watch around the axis from 6 o'clock to 12 o'clock. It is however necessary to remove the watch from the wrist to rotate the middle. Similar solutions allowing pivoting at the strap attachment are described in particular in documents GB2213612, GB2241868, EP346660, CH659167, FR2583897, CH172421, CH138929, US4470708 and CH674291.

Various known solutions also propose to insert the middle part in an external frame linked to the bracelet, and to rotate the middle part relative to the frame around a pivot, along an axis from 6 o'clock to 12 o'clock. Examples of such a watch are described in documents CH 159446, CH 176988 and EP562522 in particular.

In these solutions, the middle part is however connected to the external frame by a single pivot allowing relative movement of the box according to two degrees of freedom. Such a pivot must therefore be machined with very high precision, which increases the cost of the mechanism. Turning the watch involves moving the middle part relative to the frame along a complex three-dimensional trajectory, difficult to grasp, and generally requiring the user to grasp the lens or glasses between the fingers, leaving finger marks. Furthermore, the reliability of the turning mechanism is problematic, the pivot being able to seize or even break under the effect of impacts or even slight twists. Finally, the middle part, and more particularly the projecting members of the middle part such as the control buttons, risk coming into contact with the external frame during pivoting, which risks scratching or marking them.

Patent CH177310 describes a reversible watch comprising a middle part provided with a pivot sliding in a slide of an external frame. The middle part is turned by pivoting the case around the pivot to the vertical position, moving the pivot in the slide, then ending the pivoting of the middle. In this case also, the middle part is connected to the outer frame through a single pivot, which poses reliability problems and machining difficulties.

Other reversible watches including a turning mechanism allowing the middle to be pivoted around an axis 6 o'clock - 12 o'clock use a middle connected to an external frame by means of two pivots on the external faces of the middle guided in behind the scenes of the frame. Solutions of this type are described in particular in documents CH159982 and EP22255. In these watches, the reliability and robustness of the turning mechanism is improved thanks to the middle-frame connection at two points; moreover, the handling required for turning is more intuitive and does not require touching the glass. However, in these solutions, the turning axis of the middle part moves in a plane parallel to the watch, and therefore remains close to the bottom of the external frame. The lateral faces of the middle part must therefore be adapted to allow the middle part to be turned over without these faces touching the bottom of the external frame. In particular, it is impossible to have control buttons or winding crowns too protruding on the side face of the middle close to the turning axis; these bodies could indeed collide with the bottom of the frame during the overturning. This solution is therefore not suitable for watches comprising control members on two opposite lateral faces, in particular watches comprising both protruding control members on a first portion of the periphery of the middle between 12 o'clock and 6 o'clock , and projecting control members on a second portion of the periphery of the middle part between 6 am and 12 pm.

FR766809 describes in particular a reversible watch comprising a turning mechanism making it possible to pivot the middle around an axis from 6 o'clock to 12 o'clock. The middle part is linked to two connecting rods which are parallel to each other and articulated with respect to the watch frame. The watch is turned over by simultaneously lifting the two links then turning the middle part relative to an axis linked to the two links. It is necessary to turn the middle part by orienting the side face of the watch without winding towards the frame; the middle could not be turned over if it had control elements on the two side faces, for example both at 3 o'clock and at 9 o'clock.

Furthermore, the middle part can pivot around the axis of the turning axis even when the links are only partially raised. The middle and the winding may on this occasion come into contact with the frame 21, which could scratch or even damage them.

Finally, in most of the solutions described, most of the slides are visible at least during certain stages of the turning, which is unattractive and above all risks exposing them to dust or to skin debris which may in certain If so, block them and prevent the watch from turning over. Finally, the slides are wearing parts which cannot, or only with difficulty, be replaced when the guide of the middle becomes too imprecise.

An object of the present invention is therefore to propose a new reversible watch provided with a turning mechanism which avoids the defects of the turning mechanisms of the prior art.

In particular, an object of the present invention is to propose a sufficiently rigid and reliable turning mechanism, making it possible to turn the middle parts provided with protruding control members on one or more faces of the middle, without these control members or other parts of the middle cannot be damaged during the turning.

Another object of the present invention is to provide a turning mechanism in which the number of moving parts is reduced, in order to lower the manufacturing cost, reduce the size and improve reliability.

Another object of the present invention is to provide a reversible watch that can offer a greater number of functionalities and displays on both sides of the watch than the reversible watches of the prior art.

According to the invention, these objectives are achieved in particular by means of a reversible watch and a method comprising the characteristics of the independent claims of the corresponding type, preferential variants being indicated in the dependent claims.

In particular, these objectives are achieved by means of a reversible watch comprising a middle part provided with a first face for displaying first time indications and with a second face opposite to said first face, at least one control member for the movements of the watch projecting over a first portion of the periphery of the middle between 12 o'clock and 6 o'clock, and at least one other member controlling the movement or movements of the watch projecting over a first portion of the periphery of the middle between 6 hours and 12 hours, a turning mechanism for turning said middle around a turning axis, said turning axis being parallel to the axis from 6 to 12 o'clock during turning, so as to display, at the wearer's choice, either said first face or said second face. According to the invention, the middle part is linked to pivoting arms so as to be able to pivot around a turning axis linked to the external frame. The arms make it possible to move the turning axis during the turning; their length and arrangement are adapted to be able to turn the middle without the control members coming into contact with other parts of the watch during turning.

These objectives are also achieved using a reversible watch comprising a middle part provided with a first face to display first time indications and a second face opposite to said first face, at least one control member of the watch movements. A turning mechanism makes it possible to turn the middle around a turning axis, said turning axis being parallel to the axis from 6 am to 12 pm during the turning, so as to display, at the option of the wearer, that is said first face. , or said second face. According to the invention, the turning mechanism comprises a pivoting arm on each side of said middle. The arms move the turning axis. The middle part is linked to the arms so as to allow the middle part to be turned around the turning axis only when the arms are inclined at a predetermined angle relative to the initial position. The length of the arms is sufficient and their arrangements adapted to allow the middle part to be turned over without the control members or other parts of the middle part colliding with other parts of the watch during the turning over.

This solution has the advantage of displacing the turning axis of the middle part during the turning. It is thus possible to bring it into a more favorable position, making it possible to return large watch cases or provided with projecting control members on one or more sides, without the middle or the control members touching other parts of the watch during turning.

The present invention will be better understood using the description of examples of implementation illustrated by the appended figures which show:

Figure 1 a top view of a reversible watch according to a first variant of the invention, in the folded position with a needle display on the visible side.

FIG. 2 is a perspective view of the reversible watch according to the first variant of the invention, in the folded position with a needle display on the visible face.

Figures 3 to 10 different perspective views of the reversible watch according to the first variant of the invention, illustrated in different successive positions during turning.

Figures 11 to 14 different perspective and side views of the reversible watch according to the first variant of the invention, illustrated without in different successive positions during the reversal, in order to show in particular the slide mechanism used in the first variant.

Figures 15 to 18 different perspective views of the reversible watch according to a second variant of the invention, illustrated in different successive positions during turning. Figure 19 a sectional view of a watch case according to the invention.

Figure 1 illustrates a top view of a reversible watch according to a first embodiment of the invention. In this position, also illustrated in FIG. 2, the face 10 of the watch comprising a needle display 100 is visible on the top of the watch, the other face 11 with an alphanumeric display 110 visible in particular in FIG. 10 being turned towards the wearer's wrist. For the simplification of the figures, the display members (hands or liquid crystal display) and the bracelet are only shown in the rest positions illustrated in FIGS. 1 and 10.

The watch has a middle part 1 containing the movements of the watch and mounted in a frame 17 by means of a turning mechanism 2 described below. A bracelet 13 is fixed to the frame 17 by means of horns 171. The movement controlling the position of the

hands can be wound and / or set by time by means of a winding crown 16 on one of the lateral faces of the middle part. Other control members, here push-buttons 14, 15, make it possible to control other functions of the watch, in particular functions displayed on the other face of the watch, as described below. The control members 14, 15, 16 are distributed on two opposite lateral faces of the middle part and therefore occupy both the portion of the periphery of the middle part between 12 o'clock and 6 o'clock as well as the portion between 6 o'clock and 12 o'clock. The control members are protruding, which allows more convenient handling, on both sides of the middle part 1.

The turning mechanism of this first embodiment comprises a pivoting arm 20 and 21 closing in the folded position two opposite front faces of the frame 17. In the illustrated variant, the middle is rectangular or square and the length of the arms is substantially equal to the width of the middle. The arms can be unfolded in the manner illustrated in FIGS. 3 to 10 by pivoting in two vertical planes (that is to say perpendicular to the bottom 170 of the frame 17) around axes of rotation 200 respectively 210 linked to the frame 17 The angle of rotation reached by the arm 20 relative to its initial position is indicated in the figures by the reference α. The two axes of rotation 200 and 210 of the two arms 20 and 21 are mutually parallel and linked to diametrically opposite positions of the frame 17.

The middle part 1 is linked to the two pivoting arms 20 and 21 by two pivots 201, 211 defining an axis of reversal. It can thus be turned around the turning axis 201-211 when the arms are unfolded. In the rest position, to display one of the faces 10 or 11, the arms 20, 21 are held by balls mounted on a spring (not shown) engaged in holes 28 on the internal faces of the horns 171. A slight vertical force on the middle 1 is sufficient to release the balls and release the arms to unfold them to turn the middle.

As seen in Figures 3 to 10, the arms 20 and 21 are used to lift and align the pivots 201-211, and therefore the axis of

overturning, the middle part 1 above the initial plane containing the upper face of the middle part in the rest position. In this embodiment, the turning axis 201-211 therefore moves by pivoting the arms 20, 21 around the axis of rotation 200-210 during the turning. The manipulation necessary to lift the middle part 1 is therefore intuitive and does not require complex movements. During all the phases of the turning, the arms 20-21 connect the middle part 1 to the frame 17.

The length of the two arms 20, 21, and the distance between the axes of rotation of the arms 200-210 and the turning axis of the middle part 201-211,

10 is sufficient to allow the middle part to be turned over without the control members 14, 15, 16 or other parts of the middle part 1 coming into contact with the frame 17 or with other parts of the watch . It is thus possible to change the displayed face 10 or 11 when the arms are unfolded without risking marking, scratching or even damaging the

15 control members 14, 15, 16 or the middle part 1. As illustrated in particular in FIGS. 3 to 9, the two arms 20, 21 remain parallel with opposite orientations during the inversion.

As can be seen in particular in FIGS. 11c and 11d which represent a view of the internal face of the arm 21, respectively a

20 section of this arm along the axis Xld, the two arms 20, 21 each comprise a first slide 202 (not shown) respectively 212 in the form of A, as well as a pivot 201 (not shown) respectively 211. The pivots 201 respectively 211 move in second slides 250 respectively 260 S-shaped machined in slide holders 25

25 respectively 26 linked to the two end faces of the middle part 1. Conversely, the slide carriers 25 respectively 26 each carry two guide pivots 251 (not shown) respectively 261 moving in the first slides 202, 212.

The middle part 1 being linked to the external frame 17 by the two arms 20, 30 21 directed in opposite directions, it is moved vertically locked in a horizontal position and lifts the two arms 20, 21. By lifting the middle part 1, the pivot 211 moves in the slide 260 shaped

of S linked to the middle part and simultaneously the two pivots 261 move in the slide 212 in the form of A. Similarly, the pivots 251 move in the slide 202 of the arm 20 while the pivot 201 moves in the slide 250 linked to the slide holder 25.

5 The particular shape in A of the guide slides 202, 212 as well as the lack of alignment of the two pivots 201 and 211 makes it possible to keep the middle part 1 horizontal, that is to say parallel to its initial rest position, in all positions except the turning point illustrated in Figures 13 and 14. Indeed, the two pivots 201

10 respectively 211 are unable to rotate simultaneously, except when ^• aligned in the turning axis, positioned at 6 o'clock and 12 o'clock. In this particular position, the two pairs of guide pivots 251 and 261 are located in the circular portion of the slide 202 respectively 212. The slide holder 26 can then pivot around the pivot

15 211, the two guide pivots 261 also being free to rotate in the circular portion of the first slide 212. The slide holder 25 performs the same turning movement around the pivot 201.

The middle part 1 can thus, only in this particular position, rotate freely around the horizontal turning axis 20 201, 211. In all the other positions of the arms 20, 21, the turning is blocked by the non-alignment of the pivots 201 , 211 and by guiding the pairs of pivots 251, 261 in their respective slides. There is therefore no possible friction between the front faces of the middle part 1 and the internal face of the arms 20, 21.

In the illustrated embodiment, the turning point is reached when the angle of inclination of the arms 20, 21 is approximately 50 °, this value being chosen as a function of the length of the arms and the total width of the middle part to ensure a flipping without collision in the position illustrated in FIGS. 4 to 8 and 13 to 14. It is ensured

30 and that no point of the middle part 1 or of the control members 14, 15, 16 comes into contact with the frame 17 when the arms 20, 21 are unfolded or folded again.

The two pivots 201 and 211 define the turning axis around which the middle part 1 can be turned. As these pivots move in the second slides 250, 260 in the form of an S, the turning axis, defined by the right connecting the two pivots 201, 211, crosses the middle part 1 through the center in different directions when the arms 20 , 21 are unfolded.

The non-rectilinear S shape of the second slides 250, 260 makes it possible to control the friction forces exerted against the pivots 201, 211. In particular, this shape makes it possible to vary the reaction force exerted by friction against the slides during the unfolding and the folding of the arms 20, 21, so as to obtain a deployment effect and then more intuitive elastic folding. The turning mechanism could also function, in a less comfortable way, with second slides 250, 260 rectilinear.

In a variant not illustrated, the position of the slides and of the pivots on the middle part and the arms can be reversed. Furthermore, the "legs" of the slides 202, 212 in the form of A could be widened inwards, so as to ensure a single point of contact with the pivots 251, 261 and thus reduce friction.

To turn the middle part and display the other side of the watch, the wearer of the watch therefore lifts the middle part 1 to release the spring balls from the holes 28, then rotates the arms 20-21 by 50 ° (in this example) up to the turning position illustrated in FIGS. 4 to 8 and 13 to 14. In this position, the middle part 1 can pivot freely around the turning axis 201-211, being guided by the guide pivots 251, 261, between the two opposite horizontal positions illustrated in FIGS. 4 and 7. The wearer of the watch then pushes the middle part 1 to fold the arms 20 and 21 and reach the second rest position illustrated in FIG. 10, with the second face 11 visible. The middle part 1 is held in this position by the spring balls, not shown, engaged in other holes 28 on the internal faces of the horns 171.

The slides 250, 260 integral with the middle part 1 are wearing parts. In a preferred variant, the slide carriers 25, 26 can therefore be replaced without changing the entire middle part. They are therefore preferably attached or screwed onto the front faces of the middle part 1 by screws engaged in the holes 24; the slide carriers 25, 26 can also hide screws, not shown, making it possible to open the middle part 1 for maintenance or replacement of the battery.

It will be noted that the device described makes it possible to easily turn over the middle part 1 without having to remove the strap 13. It will also be noted that the largest portion of the different slides is hidden by the arms 20, 21, the slide holders 25, 26 and the middle part 1 in all positions, in particular in the rest positions, so that the risk of obstruction is greatly reduced.

The reversible watch of the invention advantageously comprises two distinct movements 12, 19 (FIG. 19) housed one against the other in the middle part. The first movement 12 is a mechanical movement with manual or automatic winding, making it possible to display the time, and possibly additional functions, for example a chronograph, by means of the hands 100 on the first face 10 of the watch. The second movement 19 is an electronic movement, for example a quartz movement, making it possible to display other indications, for example a second time, the date, etc., on the liquid crystal display 110 of the second face 11 The watch thus combines the advantages of a needle display with those of an alphanumeric display, as well as the advantages of a mechanical movement (prestige, operation without battery) with those of a quartz movement.

A second embodiment of the invention is illustrated in FIGS. 15 to 18. This second embodiment has the advantage of not requiring slides in the middle part 1, which makes it possible to use a thinner middle part. The slides are also fragile elements, liable to block in the event of mechanical shock or obstruction by dust or skin waste, for example. This embodiment has

however, the drawback of not entirely excluding the risk of contact between the middle part or the control members and the frame, as will be seen below.

The watch according to the second embodiment of the invention is shown in FIG. 15 in the folded position with the face 10 comprising an analog display with hands 100 visible on the top. It has a middle part 1 hingedly connected to an outer frame 17 by means of two arms 22, 23. The arms are articulated relative to the frame 17 about axes of rotation 220, 230 (FIG. 12) facing one on the other, approximately at 6 a.m. and 12 p.m. The middle part 1 is able to pivot with respect to the two arms 22, 23 about an axis of turning defined by the two pivots 221, 231.

In this variant, as can be seen in FIGS. 16 and 17 in particular, the two arms 22 and 23 remain parallel to each other at all times. The middle 1 illustrated is square or rectangular; the length of the two arms 22, 23 is less than the width of this middle part, but sufficient to allow the middle part to be turned over, when the arms are fully extended perpendicular to their initial position, without the control members 14, 15, 16 or other portions of the middle part come into contact with the frame 17. The length of the two arms 22, 23 must therefore be sufficient so that the distance between the axes of rotation 220, 230 and the axis of turning 221, 231 is greater than the sum of the half-width of the middle part increased by the thickness of said control members.

The turning axis, defined as the straight line crossing the two pivots 221, 231, crosses the middle in a fixed direction parallel to the 6 o'clock - 12 o'clock diameter, but different from this diameter. The middle 1 being fixed to the arms 22, 23 by axes without slides, the angle between this turning axis and the middle 1 remains constant throughout the turning. The connection between the arms 22, 23 and the middle part is therefore more rigid than in the first embodiment.

In the rest position illustrated in FIG. 15 with the analog face 10 visible, and in FIG. 18 with the digital face 11 visible, the arms 22, 23 are housed in the folded position in a recess of the middle part 1. The mechanism is therefore very little visible in the folded position.

To turn over the middle part 1 and choose the side 10 or 11 to be displayed, the wearer of the watch lifts the middle part 1 from the rest position illustrated in FIG. 15 to release the balls on the spring from the holes 28, then pivot the two arms 22, 23 in a vertical plane until the middle 1 is sufficiently distant from the frame 17 to allow the rotation without collision of the middle. The middle part can then be easily pivoted around the turning axis 221, 231 to choose the visible face 10 or 11 to be displayed. The arms then continue their rotation of 180 ° to fold back into the other rest position illustrated in FIG. 18. Compared to the first variant, the control members 14,

15 and 16 may possibly in this second variant come into contact with the bottom of the frame 17 if the middle part is turned too quickly or too late, that is to say when the angle α traversed by the arms 22, 23 is substantially different from 90 °. Indeed, the two pivots 221, 231 being always aligned, a reversal is possible at any point. Furthermore, the middle part 1 does not remain horizontal during all the phases of the movement.

Claims

claims 1. Reversible watch, comprising: a middle part (1) provided with a first face (10) for displaying first time indications and with a second face (11) opposite said first face, at least one control member (14 ) of the movement or movements (12, 19) of the watch on a first lateral face of said middle part, and at least one other control member (15, 16) of the movement or movements (12, 19) of the watch on a second side face of said middle opposite to said first side face, a turning mechanism (20, 21; 22, 23) for turning said middle (1) around an axis of turning (201-211; 221-231), said turning axis being parallel to the 6 o'clock-12 o'clock axis during turning, so as to display, at the wearer's choice, either said first face or said second face, characterized in that said turning mechanism comprises a pivoting arm (20, 21; 22, 23) on either side of said middle, said arms (2 0, 21; 22, 23) for moving said turning axis (201-211; 221-231), said middle part (1) being linked to said arms (20, 21; 22, 23) so as to be able to pivot around said turning axis (201-211; 221-231), the length of said arms being sufficient and their arrangements adapted to allow turning said middle part (1) without said control members colliding with other parts (17) of the watch during turning. 2. Reversible watch, comprising: a middle part (1) provided with a first face (10) for displaying first time indications and with a second face (11) opposite to said first face, at least one control member (14 ) of the movement (s) (12, 19) of the watch, a turning mechanism (20, 21) for turning said middle part (1) around an turning axis (201-211), said axis turning being parallel to the axis from 6 am to 12 pm during turning, so as to display, at the option of the wearer, either said "first face or said second face, characterized in that said turning mechanism comprises a pivoting arm ( 20, 21) on each side of said middle, said arms (20, 21) making it possible to move said turning axis (201-211), said middle (1) being linked to said arms (20, 21) so as to allow the pivoting of said middle around said turning axis (201-211) only when said arms (20, 21) are inclined at a predetermined angle (α) relative to the initial position, the length of said arms being sufficient and their arrangements adapted to allow turning over said middle part (1) without said control members colliding with other parts (17) of the watch during turning over. 3. Watch according to one of claims 1 to 2, comprising at least one control member (15, 16) of the movement or movements of the watch projecting over a first portion of the periphery of the middle between 12 o'clock and 6 o'clock, and at least one other control member (14) of the movement or movements of the watch projecting over a second portion of the periphery of the middle part between 6 o'clock and 12 o'clock. 4. Watch according to one of claims 1 to 3, wherein said arms. (20, 21; 22, 23) make it possible to lift the said turning axis (201-211; 221-231) above the initial plane containing the upper face of the middle part (1) in the rest position. 5. Watch according to one of claims 1 to 4, comprising a frame (17) linked to the bracelet (13) of the watch, said middle part (1) being inside said frame in each of the two rest positions, said turning mechanism integrally connecting said middle part (1) to said frame (17) during all the phases of said turning. 6. Watch according to claim 5, said arms (20, 21; 22, 23) closing two opposite end faces of said frame (17) in the folded position. 7. Watch according to one of claims 1 to 6, said middle pivoting with respect to said arms (20, 21; 22, 23) around two pivots (201, 211; 221, 231), said turning axis (201, 211; 221, 231) being defined by the straight line passing through said pivots. 8. Watch according to claim 7, said arms (20, 21; 22, 23) being arranged so as to move said pivots (201, 211; 221, 231) according to a single degree of freedom. 9. Watch according to claim 8, said arms (20, 21; 22, 23) being able to pivot about a fixed axis of rotation (200, 210; 220, 230). 10. Watch according to one of claims 1 to 9, said middle part (1) being rectangular or square, the length of said arms (20, 21; 22, 23) being substantially equal to the width of said middle part. 11. Watch according to one of claims 1 to 10, said arms (20, 21) being oriented in different directions during turning, said directions being oriented in two planes parallel to each other. 12. Watch according to one of claims 7 to 11, said turning axis passing through said middle (1) through the center. 13. Watch according to one of claims 7 to 12, each arm (20, 21) being connected on the one hand to said frame (17) so as to be able to pivot around said axis of rotation, said axis of rotation (200, 210 ) being fixed relative to said frame (17), each arm (20, 21) being moreover pivotally connected to said middle part (1) around said pivots (201, 211), said pivots (201, 211) being movable by relative to said middle part (1). 14. Watch according to one of claims 1 to 13, said arms (20, 21) each being linked to said middle by means of at least one pivot (201, 211) moving in at least one slide (250 , 260) during the turnaround. 15. Watch according to one of claims 7 to 14, said turning axis defined by said pivots (201, 211) passing through said middle part (1) through the center in different directions when said arms (20, 21) are unfolded. 16. Watch according to one of claims 1 to 15, said middle part (1) and said arms (20, 21) further comprising two guide slides (202, 212) and at least two guide pivots (251, 261) , at least two guide pivots moving in each of said guide slides, so as to maintain said middle part (1) parallel to its initial rest position up to the turning point. 17. Watch according to one of claims 1 to 16, said arms (20, 21) each comprising at least one pivot (201, 211) moving in a slide (250, 260) linked to the middle part (1), said middle part comprising at least one pivot (251, 261) moving in a slide (202 , 212) linked to each of said arms (20, 21), the arrangement of said slides and said pivots making it possible to keep said middle part (1) parallel to its initial rest position up to the point of turning. 18. Watch according to claim 17, comprising at least two pivots (251 respectively 261) sliding in at least one same of said slides (202 respectively 212), the shape of said slide being adapted to prevent pivoting of said two pivots except at one point corresponding to said turning point. 19. Watch according to one of claims 17 to 18, comprising at least one other slide (250, 260) linked to said S-shaped middle part. 20. Watch according to one of claims 7 to 19, said pivots (201, 211) being arranged so as to prevent overturning of said middle part (1) as long as said arms (20, 21) are not inclined beyond by an angle (α) predetermined with respect to the initial position allowing said middle part (1) to be turned over without said middle part touching said frame (17). 21. Watch according to one of claims 7 to 10, said turning axis (221, 231) crossing said middle (1) parallel to the diameter 6 o'clock - 12 o'clock of said middle. 22. Watch according to claim 21, said turning axis (221, 231) being fixed relative to said middle part throughout the reversal. 23. Watch according to one of claims 1 to 10, said arms (22, 23) moving in planes parallel to each other during the inversion. 24. Watch according to one of claims 21 to 23, said middle part (1) being rectangular or square, the length of said arms (22, 23) being less than the width of said middle part, but greater than the sum of the half width of the middle increased by the thickness of said control members, so as to allow turning said middle without said control members (14, 15, 16) coming into contact with other parts of the watch during turnaround. 25. Watch according to one of claims 21 to 24, said arms (22, 23) being received in the folded position in a recess of said middle. 26. Watch according to one of claims 21 to 25, each arm (22, 23) being connected on the one hand to said frame (17) so as to be able to pivot around said axis of rotation (220, 230), said axis of rotation (220, 230) being fixed relative to said frame (17), each arm (22, 23) being moreover pivotally connected to said middle part (17) around said pivots (221, 231), said pivots (221, 231) being fixed relative to said middle part (17). 27. Watch according to one of claims 21 to 26, said arms (22, 23) allowing said pivots (221, 231) to pivot about an axis of rotation (220, 230) linked to said frame (17). 28. Watch according to one of claims 1 to 27, comprising: a first movement (12) to display first time indications on a first face (10), a second movement (19) to display second time indications on a second face (11) opposite to said first face, control members (14, 15, 16) on two diametrically opposite faces of said middle to control the two said movements. 29. Watch according to one of claims 1 to 28, comprising: a first movement (12) for displaying first time indications on a first face, a second movement (19) for displaying second time indications on a second face (11 ) opposite to said first face, characterized in that said first movement (12) is of mechanical type and in that said second movement (19) is of electronic type. 30. Reversible watch, comprising: a middle part (1), a first movement (12) for displaying first time indications on a first face (10), a second movement (19) for displaying second time indications on a second face ( 11) opposite to said first face, a turning mechanism for turning said middle part (1) of so as to display, at the user's choice, either said first face or said second face, characterized in that said first movement (12) is of mechanical type and in that said second movement (19) is of electronic type. 31. Method for turning over a watch middle provided with a first face (10) to display first time indications and a second face (11) opposite to said first face, and at least one control member (15, 16) of the watch movement (s) comprising the following steps: displacement of the turning axis (201-211; 221-231) at a sufficient distance to allow the middle (1) of the watch to be turned over without that the control members (14, 15, 16) do not come into contact with other parts of the watch during the turning, turning of the middle around said turning axis, at least some of said control members approaching this occasion of said other parts of the watch, second movement of said turning axis. 32. The method according to claim 31, wherein said turning axis (201-211; 221-231) is moved only by a rotational movement around at least one axis of rotation (200-210; 220-230). 33. The method of claim 32, wherein said middle part (1) moves relative to said turning axis (201-211; 221-231) when the latter moves.