CH715221A2 - Elastic watch hand. - Google Patents

Abstract

The invention relates to an elastic watch hand (1) with barrels (2; 4) for driving at its ends, comprising an index (99) for displaying the cannons at a variable distance (2; 4), and comprising flexible segments (501; 502) between each barrel (2; 4) and the index (99) each with a core of substantially constant section. According to the invention, at least one flexible segment (501; 502) comprises discontinuous elements projecting from its core in a plane perpendicular to the axis (D) of the barrels (2; 4) and defining, along this core, an alternation of sections whose rigidity per unit of length is different between them, and / or at least one core comprises a succession of zones of opposite concavities, in projection on a plane perpendicular to the axis (D) of the barrels (2; 4). The invention proposes to provide an indicator with variable radial extension which is reliable and robust.

Description

Description Field of the Invention The invention relates to an elastic timepiece needle with variable geometry, comprising a first drive barrel secured to a first end of a flexible blade, and a second drive barrel secured from another end of said flexible blade, and having a display index which, in an unstressed free state of said elastic needle in which both said first barrel and said second barrel are not stressed and are distant from each other, is spaced from said first barrel and from said second barrel, the service position of said elastic needle being a constrained position where said first barrel and said second barrel are coaxial with each other around an output axis, said display mechanism comprising first means for driving said first barrel around said output axis, and second means for driving said second barrel around said outlet axis, said first driving means and second driving means being arranged to deform said flexible blade, by varying the angular position of said second barrel relative to the angular position of said first barrel around said output axis, and to vary the radial position of said display index relative to said output axis, said elastic needle comprising at least a first flexible segment between said first barrel and said index with a first core of substantially constant section, and a second flexible segment between said second barrel and said index with a second core of substantially constant section.

The invention also relates to a timepiece movement comprising at least one such display mechanism.

The invention also relates to a timepiece comprising at least one such clockwork movement, or / and comprising at least one such display mechanism.

The invention also relates to a scientific apparatus comprising at least one such clockwork movement, and / or comprising at least one such display mechanism.

The invention relates to the field of analog display mechanisms by mobile mechanical components, for timepieces or scientific apparatus.

Background of the invention [0006] The documents EP 2 863 274 and EP 3 159 751 in the name of MONTRES BREGUET SA describe different arrangements of elastic hands, allowing the adaptation of a display on a timepiece to the shape of its case or of its dial, thanks to a radial extension obtained by piloting such an elastic needle comprising distinctly driven flexible segments.

Claims (21)

Summary of the invention The invention proposes to provide a reliable and very robust solution to the problem of providing a variable radial extension indicator according to its position and its control. To this end, the invention relates to a clockwork display mechanism comprising at least one such elastic needle, which comprises a first drive shaft secured to at least one flexible blade, according to claim 1. The invention also relates to a timepiece movement comprising at least one such display mechanism. The invention also relates to a timepiece comprising at least one such clockwork movement, or / and comprising at least one such display mechanism. The invention also relates to a scientific apparatus comprising at least one such clockwork movement, and / or comprising at least one such display mechanism. Brief description of the drawings [0012] Other characteristics and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, where: fig. 1 shows, diagrammatically, in plan view, and with a perspective view of a detail of its apex, an elastic needle according to the teachings of applications EP 2 863 274 and EP 3 159 751 comprising two smooth flexible blades, each joining the common apex and a respective barrel; fig. 2 shows, schematically and in plan view, a needle according to the invention which comprises, on each of its two branches, discontinuous elements distributed along a core, which has a substantially constant section; fig. 3 shows, in perspective, a detail of a branch of FIG. 2, where the discontinuous elements are cylinders centered on the core; CH 715 221 A2 fig. 4 represents, similarly to FIG. 3, another variant where the discontinuous elements are substantially planar plates or sheets, extending substantially in the plane of the needle in its non-prestressed rest position, each plate being attached to the core by a thin junction bar ; in this fig. 4 the plates extend on both sides of the core; fig. 5 represents, similarly to FIG. 4, another variant with sheets of height less than that of the core, and on one side of the core; fig. 6 represents, similarly to FIG. 5, another variant with sheets on one side of the core, with contours substantially complementary to each other; fig. 7 represents, similarly to FIG. 4, another variant with sheets on one side of the core, these sheets, different from each other, here constitute letters or numbers; fig. 8 is a detail of fig. 7 in the vicinity of the summit; fig. 9 shows, schematically, in plan view, the maximum cooperation between such an elastic needle, shown deformed in broken lines for example during an impact, with an inner surface of a watch case or an element of covering, which limits the travel of the outermost deformed branch of the needle; fig. 10 is another illustration, in plan view, of the deformation of such an elastic needle, with, this time, the limitation at the level of the common axis of the two guns; fig. 11 represents, schematically, in plan view, and with a magnifying glass a detail of one of its branches, an elastic needle whose core develops in serpentine on both sides of a medium profile; fig. 12 shows, schematically and in perspective, a flexible composite needle whose flexible branches are butted on a common rigid apex, and each on one of the barrels; fig. 13 shows, diagrammatically and in perspective, a flexible composite needle, the barrel ends of which are each halfway up the needle; fig. 14 shows schematically and in section two variants of elastic needle core having a section other than rectangular: trapezoid on the left, parallelogram on the right; fig. 15 to 17 schematically illustrate, in plan view, the variations in length of an elastic needle according to the invention, in the free state in FIG. 15, in a first relative position of the barrels in FIG. 16 where the needle has its maximum radial development, and in a second relative position of the barrels in FIG. 17 where the needle has its minimal radial development; fig. 18 to 20 represent, analogously to FIGS. 15 to 17, a needle with very differentiated branches, to perform an indicative day display in fig. 19 and at night in fig. 20; fig. 21 shows schematically and in section, a timepiece, in particular a watch, comprising such an elastic needle superimposed on a traditional needle, where, to avoid any interference between these needles, the traditional needle is housed in a recess of the dial or of a plate, and where an offset plane serves as an abutment bearing surface for the elastic needle in any position of its development; fig. 22 is a block diagram representing a timepiece, in particular a watch, comprising a display mechanism comprising such an elastic hand. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] The elastic needle technology offers a large number of new display possibilities, which allow customizations that are always in great demand, especially for watches. However, it is necessary to ensure the best possible readability of the needle: a needle comprising arms with a thickness of 40 μm and a height of 200 μm is thus very fine, and it is advantageous to be able to increase its readability , and also to propose new functions linked to the particular arrangement of the arms of the needle. [0015] FIG. 1 illustrates such a fine elastic needle 1 comprising arms 3 which have a thickness of 40 μm and a height of 200 μm, which develop between their respective barrels 2 and 4, and a common apex forming an index 99. CH 715 221 A2 [0016] The term "height" is used here to refer to any dimension measured in the direction of an output shaft D, which is the common axis of the two guns 2 and 4. A dimension measured in a plane perpendicular to this exit axis D. This elastic needle 1 comprises at least a first flexible segment 501 between the first barrel 2 and the index 99 with a first core 601 of substantially constant section, and a second flexible segment 502 between the second barrel 4 and the index 99 with a second core 602 of substantially constant section. Figs. 2 and 3 illustrate a variant analogous to a collar structure. The needle is always made in one level. Larger elements, here small discontinuous cylindrical elements 701, are distributed over the arms of the needle to make it more visible, as visible on a first flexible segment 501 of the arm 3. The links 801 between these elements must be thinned 701 in order to keep the same flexibility of the needle 1. Of course, the mass of such small discontinuous cylindrical elements 701 must remain reasonable, to avoid excessive deformation in the event of an impact of the excessively heavy needle, which deforms more, especially since the links 801 between the elements 701 are more flexible than in the standard case of FIG. 1. To minimize the stiffening of the needle 1 by large islets or balls, the rigid part can be reduced with sheet-like structures, in particular over the entire height, as shown in the variant of FIG. 4, the inertia of which remains significant. Figs. 5 to 8 illustrate sheet structures of lower inertia, where the needle 1 is produced in two levels. The needle has a main structure, for example with a thickness of 40 μm and a height of 200 μm as in fig. 1. On this structure is grafted sheets 701, or other structures, like the letters of figs. 7 and 8, of a lower height, for example 40 μm in height, to make the needle 1 more visible. [0021] FIG. 6 shows sheets or plates on one side of the core, with contours substantially complementary to each other, arranged to allow bending of the arm of the needle without these sheets 701 interfering with each other, while presenting the user with an almost continuous, fairly large surface, with good contrast with the surrounding background, dial or the like. The example of Figs. 7 and 8 thus show, in a nonlimiting manner, sheets formed by letters 701 or numbers 702, 40 μm in height. The advantage is that the needle 1 is not weighed down or made too rigid. It is important to understand that each letter set 30 has a sheet of letter 31 which is attached to the needle by a small rod 32 which does not stiffen the structure. The protection of an elastic needle against impact is important, because, in the event of impact, the needle may touch, or a component of the structure of the watch such as an inner surface 15 of the bezel 14 in fig. . 9, or the central barrel 2 or 4 as visible in FIG. 10. It is for this reason that the variant of sheet structure is interesting. One can advantageously position the sheets, or the letters, or the like, on the internal flank of the needle only in the vicinity of the point, because the internal flank does not come into contact with the telescope, and on the other hand the sheets do not not likely to bend because it is the rod of the needle which stores the shock, and in particular in the vicinity of the barrels, where the needle preferably does not have a sheet. [0025] FIG. 11 illustrates yet another variant, with the needle made, at least locally, in a serpentine. [0026] FIG. 12 illustrates a variant where the needle is assembled. For this purpose, you must make the top and the barrels of needles separately, and come to glue, crimp, weld, solder, screw or pin, or similar, the arms of the needle in these components. For example, the arms of the needle can be made of a noble polymer, for example carbon fiber, or of a super elastic alloy of the "Nitinol" type or the like. The advantage of these materials is to better withstand shocks because they are capable of storing large deformations. [0027] FIG. 13 illustrates a variant to reduce the axial size of the needle, by making the barrels in several levels, so that they are complementary to the assembly. [0028] FIG. 14 shows sections allowing a three-dimensional deformation of the needle, which can prove advantageous to pass over an obstacle, or to create a particular optical effect. The section of the needle in fig. 1 is rectangular. It is possible to imagine a trapezoidal or parallelepipedal needle section. When putting the needle under stress, it deforms out of plane and it can then pass over an obstacle such as a wall lamp, a window, a cage, or other, which amounts to designing a trajectory specific to avoid an element of the dial or watch. Figs. 15 to 17 illustrate the variations in length of an elastic needle which, in the long position, has a leaf shape and, in the short position, a drop shape. The fact of superimposing zones 901.902, located in the vicinity of cannons 2 and 4, makes it possible to display additional information, for example by the form of sector closed at 120 ° in FIG. 17, which can correspond to a particular time slot, Or other. Figs. 18 to 20 represent, a needle with very differentiated branches, for performing an indicative day display in fig. 19 and at night in fig. 20. An indication is then made with the lateral movement of the needle, or the angle of the CH 715 221 A2 bases, and not necessarily with the top of the needle. Of course we can combine the displays resulting from the angular position and the radial position of the vertex, with the indications given by the partial or total superposition of the branches of the needle. Here, for example, we make letters 5001 on the left arm 502 of the needle and a wider area 5002 on the right arm 501. When the two arms of the needle overlap, the wider area 5002 hides the text 5001 written on the left arm. The invention makes it possible to couple two pieces of information, for example hours and minutes, on the same hand. For example, the angular indication of the hand represents the hour, the length of the hand indicates the minutes. In a variant, the needle does not rotate on itself but only changes in length, to display information on a line. This can be used in particular for a function selector, a power reserve display, or other. [0033] FIG. 21 shows a hand, in particular an hour hand 11, which is enclosed in a recess 12, because the elastic hand can always undergo a significant deformation, in particular more important than a conventional hand, during impacts. To avoid, for example, an elastic minute hand getting tangled with the hour hand, it is possible to make a lower hand short enough not to get tangled, or, as illustrated, a hand buried in the dial so as not to be accessible by the elastic needle, the axial stroke of which is limited by an upper surface 16 of a dial 13, or the like. Thus, the invention relates to an elastic watch hand 1 with variable geometry, comprising a first drive barrel 2 integral with a first end of a flexible blade 3, and a second barrel 4 integral drive from another end of the flexible blade 3, and having a display index 99. In an unconstrained free state of the elastic needle 1 in which both the first barrel 2 and the second barrel 4 are not subjected to any stress and are distant from each other, this index 99 is distant from the first barrel 2 and of the second barrel 4. The service position of the elastic needle 1 is a constrained position where the first barrel 2 and the second barrel 4 are coaxial with one another around an outlet axis D. The display mechanism 10 includes first drive means 11 of the first barrel 2 around the outlet axis D, and second drive means 13 of the second barrel 4 around the outlet axis D The first drive means 11 and the second drive means 13 are arranged to deform the flexible blade 3, by varying the angular position of the second barrel 4 relative to the angular position of the first barrel 2 around the axis. output D, and to vary the radial position of the display index 99 relative to the output axis D. The elastic needle 1 comprises at least a first flexible segment 501 between the first barrel 2 and the index 99 with a first core 601 of substantially constant section, and a second flexible segment 502 between the second barrel and the index 99 with a second core 602 of substantially constant section. According to the invention, the first flexible segment 501 comprises first discontinuous elements 701 projecting from the first core 601 and extending substantially parallel to a plane perpendicular to the outlet axis D and defining, along the first core 601, an alternation of sections whose stiffness per unit of length is different between them, and / or the second flexible segment 502 comprises second discontinuous elements 702 projecting from the second core 602 and extending substantially parallel to a plane perpendicular to the output axis D and defining, along the second core 602, an alternation of sections whose rigidity per unit of length is different between them, and / or the first core 601 and / or the second core 602 comprises a succession zones of opposite concavities, projected onto a plane perpendicular to the outlet axis D. More particularly, the first flexible segment 501 comprises first discontinuous elements 701 projecting from the first core 601 and extending substantially parallel to a plane perpendicular to the outlet axis D and defining, along the first core 601 , an alternation of sections whose rigidity per unit of length is different between them, and / or the second flexible segment 502 comprises second discontinuous elements 702 projecting from the second core 602 and extending substantially parallel to a plane perpendicular to the output axis D and defining, along the second core 602, an alternation of sections whose rigidity per unit of length is different between them, and the first elements 701 and / or the second elements 702 are inertial elements each an inertia greater than the inertia of elastic sections 801, 802, of the first core 601, respectively second core 602, in tercalés between first elements 701 and / or respectively second successive elements 702. More particularly, the first flexible segment 501 comprises first discontinuous elements 701 projecting from the first core 601 and extending substantially parallel to a plane perpendicular to the outlet axis D and defining, along the first core 601 , an alternation of sections whose rigidity per unit of length is different between them, and / or the second flexible segment 502 comprises second discontinuous elements 702 projecting from the second core 602 and extending substantially parallel to a plane perpendicular to the output axis D and defining, along the second core 602, an alternation of sections whose rigidity per unit of length is different between them. And, more particularly, in the direction of the outlet axis D, the height of the first elements 701 and / or of the second elements 702 is less than that of the core 601,602, respectively. CH 715 221 A2 More particularly, according to the direction of the outlet axis D, the first elements 701 are arranged at a first level sufficiently distant from a second level at which the second elements 702 are arranged, to allow their superposition and their crossing at a distance during the elongation or contraction of the elastic needle 1. More particularly, the first elements 701 and the second elements 702 extend only on an inner side of the elastic needle 1 delimited by the first core 601 and the second core 602, to ensure, in the event of an impact, direct support of the first core 601 or the second core 602 on an element of a timepiece in which the elastic needle 1 is incorporated. More particularly, the first elements 701 and the second elements 702 are only present in the vicinity of the index 99, and, in the vicinity of the first barrel 2 and the barrel 4, the elastic needle 1 only has the first core 601 and the second core 602, over a curvilinear length sufficient to ensure, in the event of an impact, direct support of the first core 601 or the second core 602 on the first gun 2 or the second gun 4. More particularly, at least part of the flexible blade 3 comprises a flat elastic blade wound in a serpentine. More particularly, at least part of the flexible blade 3 is of trapezoidal section or oblique parallelogram, so as to allow deformation out of plane during at least part of the elongation or retraction of the elastic needle 1 . More particularly, the one-piece elastic needle 1 comprises at least part of the flexible blade 3 made of carbon fiber or a super elastic alloy irreversibly secured to a solid top element 69 at the level of an index 99 of a part, and a first cannon 2 or second cannon 4 on the other hand. More particularly, the elastic needle 1 is arranged to occupy a first long configuration in the form of a sheet or a second short configuration in the form of a drop. More particularly, the elastic needle 1 comprises at least a first flexible segment 501 comprising a first decoration 5001, and a second flexible segment 502 comprising a second decoration 5002 which is arranged to overlap over a part of the stroke relative angle between the first barrel 2 and the second barrel 4, all or part of the first decoration 5001, or vice versa. More particularly, the first decoration 5001 or second decoration 5002 includes an indication of day / night or of AM / PM arranged to be seen by the user, and the second decoration 5002 or respectively the first decoration 5001 is arranged to mask completely this indication for an appropriate time range. More particularly, the first core 601 and or the second core 602 comprises a strand 30 whose largest dimension of its section is substantially parallel to the outlet axis D, and the elastic needle 1 comprises, in at least a plane perpendicular to the output axis D, a plurality of inertial elements 31 each attached to the strand by a rod 32 of section smaller than that of the strand 30 and to the smallest section of the inertial element 31 which is constituted by a first element 701 or by a second element 702. More particularly, the first barrel 2 or second barrel 4 secured to the flexible blade 3 has an end flange 249 of lesser height than that of the flexible blade 3 for its superposition with another second barrel 4 or first barrel 2 . More particularly, the flexible blade 3 is composed of a plurality of flexible segments 5 connected end to end at the level of vertices 6, including at least a first segment 5, 520, which carries the first barrel 2 at a first end 52 and is flexible between the first barrel 2 and a first of the vertices 6, the elastic needle 1 comprising a second segment 5, 540, carrying the second barrel 4 at a second end 54. The invention also relates to a clockwork display mechanism 10, of variable geometry, comprising at least one such elastic needle 1, and first drive means 101 of the first barrel 2 and second drive means 102 of the second barrel 4. More particularly, the display mechanism 10 is arranged to display a first quantity by the angular position of the elastic needle 1, and to display a second quantity by the elongation, relative to the axis outlet D, of the elastic needle 1. More particularly, the first drive means 101 and the second drive means 102 are arranged to maintain the angular position in a fixed position, and to provide a linear display given by the mere elongation of the elastic needle 1 . More particularly, the first drive means 101 or the second drive means 102 are kept stationary. More particularly, the display mechanism 10 comprises at least one other display needle 11 operating in a counterbore 12 of a dial 13 or of a structure, and the outer diameter of the counterbore 12 is smaller than the smallest elongation of the elastic needle 1 which is arranged above an upper surface 16 of the dial 13, located above the other needle 11. CH 715 221 A2 More particularly, the display mechanism 10 comprises means for piloting the first drive means 101 and second drive means 102, which are arranged to control a retraction or a twist outside the plane of the elastic needle 1 in the vicinity of an obstacle interfering with its trajectory. The invention also relates to a timepiece 1000, in particular a watch, comprising at least one such display mechanism 10, and / or at least one such elastic needle 1. claims 1. Elastic needle (1) of variable geometry timepieces, comprising a first drive barrel (2) integral with a first end of a flexible blade (3), and a second barrel (4) integral drive from another end of said flexible blade (3), and comprising a display index (99) which, in an unconstrained free state of said elastic needle (1) in which both said first barrel (2) and said second barrel (4) is not subjected to any stress and are distant from each other, is distant from said first barrel (2) and from said second barrel (4), the service position of said elastic needle (1) being a constrained position where said first barrel (2) and said second barrel (4) are coaxial to each other around an output axis (D), said display mechanism (10) comprising first means drive (11) of said first barrel (2) around said outlet axis (D), and second drive means (13) of said second barrel (4) around said outlet axis (D), said first drive means (11) and second drive means (13) being arranged to deform said flexible blade (3) , by varying the angular position of said second barrel (4) relative to the angular position of said first barrel (2) around said outlet axis (D), and to vary the radial position of said display index (99) by relative to said outlet axis (D), said elastic needle (1) comprising at least a first flexible segment (501) between said first barrel (2) and said index (99) with a first core (601) of substantially constant section, and a second flexible segment (502) between said second barrel and said index (99) with a second core (602) of substantially constant section, characterized in that said first flexible segment (501) comprises first projecting discontinuous elements (701) from said first â me (601) and extending substantially parallel to a plane perpendicular to said outlet axis (D) and defining, along said first core (601), an alternation of sections whose stiffness per unit of length is different between them, and / or said second flexible segment (502) comprises second discontinuous elements (702) projecting from said second core (602) and extending substantially parallel to a plane perpendicular to said exit axis (D) and defining, along said second core (602), an alternation of sections whose rigidity per unit of length is different between them, and / or in that said first core (601) and / or said second core (602) comprises a succession of zones of concavities opposite, in projection on a plane perpendicular to said exit axis (D). 2. elastic needle (1) according to claim 1, characterized in that said first flexible segment (501) comprises first discontinuous elements (701) projecting from said first core (601) and extending substantially parallel to a plane perpendicular to said exit axis (D) and defining, along said first core (601), an alternation of sections whose stiffness per unit of length is different between them, and / or said second flexible segment (502) comprises second elements ( 702) discontinuity projecting from said second core (602) and extending substantially parallel to a plane perpendicular to said outlet axis (D) and defining, along said second core (602), an alternation of sections whose rigidity per unit of length is different between them, and in that said first elements (701) and / or said second elements (702) are inertial elements each with an inertia greater than l ’Inertia of elastic sections (801; 802) of said first core (601), respectively second core (602), inserted between said first successive elements (701) and / or respectively second elements (702). 3. elastic needle (1) according to claim 1 or 2, characterized in that said first flexible segment (501) comprises first discontinuous elements (701) projecting from said first core (601) and extending substantially parallel to a plane perpendicular to said exit axis (D) and defining, along said first core (601), an alternation of sections whose stiffness per unit of length is different between them, and / or said second flexible segment (502) comprises second discontinuous elements (702) projecting from said second core (602) and extending substantially parallel to a plane perpendicular to said outlet axis (D) and defining, along said second core (602), an alternation of sections whose rigidity per unit of length is different between them, and characterized in that, according to the direction of said outlet axis (D), the height of said first elements (701) and / or of said second elements (702) is less than that of said core (601; 602) respectively. 4. elastic needle (1) according to claim 2 or 3, characterized in that, in the direction of said outlet axis (D), said first elements (701) are arranged at a first level sufficiently distant from a second level at which are arranged said second elements (702) to allow their superposition and their crossing at a distance during the elongation or contraction of said elastic needle (1). 5. elastic needle (1) according to one of claims 2 to 4, characterized in that said first elements (701) and said second elements (702) extend only on an inner side of said elastic needle (1) delimited by said first core (601) and said second core (602), to ensure, in the event of impact, a direct support of said first core (601) or said second core (602) on an element of a piece of timepiece which incorporates said elastic hand 0). CH 715 221 A2 6. elastic needle (1) according to one of claims 2 to 5, characterized in that said first elements (701) and said second elements (702) are only present in the vicinity of said index (99), and that, in the vicinity of said first barrel (2) and said barrel (4), said elastic needle (1) comprises only said first core (601) and said second core (602), over a curvilinear length sufficient to ensure, in the event of impact , direct support of said first core (601) or said second core (602) on said first barrel (2) or said second barrel (4). 7. Elastic needle (1) according to one of claims 1 to 6, characterized in that at least part of said flexible blade (3) comprises a flat elastic blade wound in a serpentine. 8. elastic needle (1) according to one of claims 1 to 7, characterized in that at least part of said flexible blade (3) is of trapezoidal section or oblique parallelogram, so as to allow deformation out of plane for at least one part of the elongation or retraction of said elastic needle (1). 9. elastic needle (1) according to one of claims 1 to 8, characterized in that said elastic needle (1) in one piece comprises at least a portion of said flexible blade (3) of carbon fiber or irreversibly super elastic alloy integral with a solid top element (69) at the level of a said index (99) on the one hand, and of a said first barrel (2) or second barrel (4) on the other hand. 10. Elastic needle (1) according to one of claims 1 to 9, characterized in that said elastic needle (1) is arranged to occupy a first long configuration in the form of a sheet or a second short configuration in the form of a drop. 11. elastic needle (1) according to one of claims 1 to 10, characterized in that said elastic needle (1) comprises at least a first flexible segment (501) comprising a first decoration (5001), and a second flexible segment (502 ) comprising a second decoration (5002) which is arranged to cover in superposition, over part of the relative angular travel between said first barrel (2) and said second barrel (4), all or part of said first decoration (5001), or Conversely. 12. Elastic needle (1) according to claim 11, characterized in that said first decoration (5001) or second decoration (5002) includes an indication of day / night or of AM / PM arranged to be seen by the user, and in that said second decoration (5002) or respectively said first decoration (5001) is arranged to completely mask said indication for an appropriate period of time. 13. elastic needle (1) according to one of claims 1 to 12, characterized in that said first core (601) and or said second core (602) comprises a strand (30) whose largest dimension of its section is substantially parallel to said outlet axis (D), and in that said elastic needle (1) comprises, in at least one plane perpendicular to said outlet axis (D), a plurality of inertial elements (31) each attached to said strand by a rod (32) of section smaller than that of said strand (30) and the smallest section of said inertial element (31) which is constituted by said first element (701) or by said second element (702). 14. elastic needle (1) according to one of claims 1 to 12, characterized in that said first barrel (2) or second barrel (4) integral with said flexible blade (3) comprises an end flange (249) of lesser height than that of said flexible blade (3) for its superposition with another said second barrel (4) or first barrel (2). 15. elastic needle (1) according to one of claims 1 to 13, characterized in that said flexible blade (3) is composed of a plurality of flexible segments (5) connected end to end at vertices (6) , including at least a first segment (5, 520) which carries said first barrel (2) at a first end (52) and is flexible between said first barrel (2) and a first of said vertices (6), said elastic needle ( 1) comprising a second said segment (5, 540) carrying said second barrel (4) at a second end (54). 16. Clock display mechanism (10), with variable geometry, comprising at least one elastic needle (1) according to one of claims 1 to 14, and first drive means (101) of said first barrel ( 2) and second drive means (102) of said second barrel (4), characterized in that said display mechanism (10) is arranged to display a first quantity by the angular position of said elastic needle (1), and to display a second quantity by the elongation, relative to said outlet axis D), of said elastic needle (1). 17. Clock display mechanism (10) according to claim 15, characterized in that said first drive means (101) and said second drive means (102) are arranged to maintain said angular position in a fixed position, and to provide a linear display given by the simple elongation of said elastic needle (1). 18. Clock display mechanism (10) according to claim 16, characterized in that said first drive means (101) or said second drive means (102) are kept stationary. 19. Clock display mechanism (10) according to one of claims 16 to 18, characterized in that said display mechanism (10) comprises at least one other display needle (11) operating in a the counterbore (12) of a dial (13) or of a structure, and the outside diameter of the said counterbore (12) is smaller than the smallest elongation of the said elastic needle (1) which is arranged above a upper surface (16) of said dial (13), located above said other needle (11). CH 715 221 A2 20. Clock display mechanism (10) according to one of claims 16 to 19, characterized in that said display mechanism (10) comprises means for controlling said first drive means (101) and said second drive means (102), which are arranged to control an out-of-plane retraction or twisting of said elastic needle (1) in the vicinity of an obstacle interfering with its trajectory. 21. Timepiece (1000) comprising at least one display mechanism (10) according to one of claims 15 to 20, and / or at least one elastic hand (1) according to one of claims 1 to 14 . CH 715 221 A2

701 CH 715 221 A2

CH 715 221 A2

CH 715 221 A2