This application claims priority from European patent application No. 16177616.6 filed Jul. 1, 2016, the entire disclosure of which is hereby incorporated herein by reference.
The present invention concerns a device for switching a timepiece mechanism between two operational states.
More particularly, the invention concerns a timepiece comprising:
The switching device is of the bistable type. It is arranged so that said at least one part of the switching member is capable of passing on demand from a first stable axial position to a second stable axial position, to cause a first switch of the timepiece mechanism between its first state and its second state, and from the second stable axial position to the first stable axial position to cause a second switch of the timepiece mechanism between its second state and its first state.
The timepiece mechanism may have several different functions for which the switching device defines a bistable switch, alternately making it possible to start or stop the function or alternatively to couple and uncouple this function.
A bistable vertical coupling device described in EP Patent 2015145 meets the definition of the device given in the field of the invention. This device is provided for alternately starting and then stopping a chronograph mechanism. It includes for such purpose a switching mechanism including a coupling wheel permanently coupled to an output wheel, a coupling cone associated with a control member, a spring exerting an axial force between the first wheel and a plate forming a stop, a central tube for joining the plate to the assembly formed of the coupling wheel and the coupling cone, and finally a joint allowing friction coupling of said assembly to an input wheel.
The switching mechanism is actuated axially (i.e. perpendicularly to the respective planes of the input wheel and of the output wheel) by a control mechanism, which includes a clamp with two fingers, carrying, at their respective free ends, portions that each have an oblique surface for pressing laterally on the coupling cone (which consequently defines an uncoupling cone), and a column wheel which is driven step-by-step into a plurality of angular positions by means of an actuation device, notably a push-piece actuatable by the timepiece user. This column wheel actuates the clamp, in collaboration with a strip-spring, to alternately lift the assembly formed of the coupling wheel and the coupling cone against the axial force of the spring and uncouple the chronograph mechanism and remove the lateral pressure on this assembly in order to couple the chronograph mechanism, this coupling being achieved by the spring and the friction joint.
As is clear from the description above, the vertical coupling device of EP2015145 is relatively complex. Firstly, it requires a spring incorporated in the switching mechanism. Next, it occupies a lot of space in the general plane of the movement and it has quite a large height, due to the superposition of several elements, particularly of the coupling cone, the spring and the stop-plate. Finally, the control mechanism is not easy to fabricate and then assemble inside the timepiece movement.
The invention proposes to provide a switching device, in particular a bistable coupling device, of a novel type compared to that of the prior art described above, notably to overcome the drawbacks of this prior art.
To this end, the invention concerns a timepiece as defined in the main claim of the appended set of claims. Thus, the invention concerns a timepiece generally defined in the field of the invention and which is characterized in that:
As a result of the features of the invention, the switching member can switch alternately between its two stable axial positions as a result of a magnetic force alternately produced in both senses of the axial direction by the two magnetic structures, respectively forming the control member and the switching member, when the control member is driven successively step-by-step into a plurality of predefined angular positions. Other particular advantages of the present invention will appear from the following description of the invention.
Various embodiments and variants form the subject of secondary claims of the appended set of claims. Thus, notably, in a particular embodiment, the switching member includes axial guiding arranged to allow an axial translation in both directions of this switching member when the control member is actuated in rotation and to prevent the switching member being driven in rotation upon such actuation. In a particular application, the switching device forms a coupling/uncoupling device. The switching member carries a coupling element arranged to rotate freely, at least in one axial position of the first and second stable axial positions, corresponding to a coupled state of the switching device and thus of the associated timepiece mechanism, the coupling element being integral with the switching member in axial translation.
The invention will be described below with reference to the annexed drawings, given by way of non-limiting example, and in which:
A first embodiment of a timepiece according to the invention will be described with reference to
Switching device 4 is arranged to be able to switch the timepiece mechanism between its first and second states. To this end, it includes a control member 16, which extends in a general plane 18 in which it is subjectable to a pivoting motion (rotation on itself) under the action of an actuation device (partially represented in
According to the invention, the control member and the switching member respectively include a first magnetic structure 32 and a second magnetic structure 34 exhibiting a magnetic interaction therebetween. Generally, one of the first and second magnetic structures, includes at least a first magnetic pole and the other of these two magnetic structures includes at least a second magnetic pole and a third magnetic pole with opposite polarities. The first and second magnetic structures are arranged such that, in a first angular position of the control member of the plurality of its distinct angular positions, the first magnetic pole mainly exhibits a first magnetic interaction with one of the second and third magnetic poles and such that, in a second angular position of this control member of the plurality of distinct angular positions, this first magnetic pole mainly exhibits a second magnetic interaction with the other of the second and third magnetic poles. The first and second magnetic interactions produce on the switching member a first magnetic force and a second magnetic force respectively, both oriented along axis of rotation 36 of the control member in opposite senses, which makes it possible to move the switching member from its first stable axial position to its second stable axial position and vice versa. More particularly, the first and second magnetic structures are arranged such that the switching member is subjected to an alternate movement between its first and second stable axial positions when the second magnetic structure, integral with the control member, is driven in rotation step-by-step in said given direction of rotation, which thus makes it possible, on demand, to switch the timepiece mechanism between its first and second states.
The rotating control member is arranged to make steps each corresponding to a pivoting motion of angle π/N, with N>0, such that first magnetic structure 32 is made to occupy in succession 2N distinct angular positions about axis of rotation 36. Generally, in such a case, one of the first and second magnetic structures includes N first active magnetic poles, which are substantially axially oriented and, when N>1, regularly distributed around axis of rotation 36, whereas the other of these two magnetic structures includes N second active magnetic poles and N third active magnetic poles which are substantially axially oriented and regularly distributed around the axis of rotation and at substantially the same distance from this axis of rotation as the first magnetic poles. The second and third magnetic poles are arranged alternately, such that each second magnetic pole is inserted between two third magnetic poles. Further, in each of the distinct angular positions of the control member, the N first magnetic poles are located substantially facing the N second magnetic poles or N third magnetic poles. In the variant represented in the Figures, N is equal to four (N=4). An “active” magnetic pole means a magnetic pole participating in the magnetic interaction provided in the magnetic system causing axial translations in both directions of the switching member.
In the variant represented in
In a main variant, represented in
In a variant (not represented), at least the magnetic structure carrying the second and third magnetic poles is formed by a multipolar magnet including 2N active poles which are alternated and axially oriented. It will be noted that the other magnetic structure may also be formed by a multipolar magnet with axially oriented poles, in particular when it also includes 2N alternate active poles.
The switching member includes axial guiding arranged to allow an axial translation in both directions of the switching member when the control member is actuated in rotation and to prevent the switching member being driven in rotation upon such actuation. In the first embodiment, switching member 12 is guided in axial translation (along axis of rotation 36) by at least a first column 46 located at the periphery of the control member and sliding into an aperture in base 14. Preferably, a second column 48 is also provided here for axial guiding, the first and second columns being advantageously diametrically opposite relative to the axis of rotation, as represented in
As a result of the arrangement of the switching device according to the invention, when control member 16 is driven step-by-step into the plurality of distinct stable angular positions (2N positions), switching member 12 is subjected to an axial magnetic force alternately in both senses of the direction defined by axis of rotation 36. When the two magnets of the pairs of bipolar magnets 42 and 44, located facing each other, are magnetically oriented in the same sense, the magnetic force is a force of magnetic attraction and the switching member is thus attracted to the control member. Conversely, when the two magnets of these pairs of bipolar magnets 42 and 44 are magnetically oriented in an opposite sense, the magnetic force is a force of magnetic repulsion and the switching member is then repelled away from the control member.
To limit the translation possible for the switching member in the two senses, the timepiece further includes at least a first stop 52 and at least a second stop 54 respectively arranged to define two stable axial positions of the switching member, this switching member abutting against one or other of these first and second stops respectively in its two stable axial positions under the action of the magnetic force produced between the first and second magnetic structures. The two stable axial positions of the switching member respectively define an uncoupling position and a coupling position in which the associated timepiece mechanism is respectively in an uncoupled state and a coupled state. In the case represented in the Figures, coupling wheel 10 is meshed with pinion 6 in the coupling position of the switching member, whereas in the uncoupling position, this coupling wheel is no longer meshed with the pinion (no meshing relation between them). In order to best set the coupling position, stop 54 is height adjustable. In the variant represented, this stop is formed by at least one screw in the threaded hole of bar 30.
Further, means are provided for substantially securing the coupling wheel to the switching member in the axial direction, so that this wheel follows the movement of axial translation of the switching member. In the variant represented, two curved fingers 56 and 58 projecting from the plate of the switching member form therewith two C-shaped elements around the coupling wheel toothing 10A. Thus, this coupling wheel has a very limited axial travel in both senses relative to the switching member. Moreover, by way of improvement, means are provided for allowing optimum rotation of the coupling wheel in the coupling position of the switching member. To this end, to guide the coupling wheel on the side of the switching member plate, arbor 26 of this wheel has a pivot 60 arranged in a lower bearing 62. Next, the upper bearing includes a setting 64 in which are inserted jewel hole 28 and an endstone 66 at a certain distance from the jewel hole, this distance being intended to avoid hindering the sliding of arbor 26 through the jewel hole when the switching member is pushed into its coupling position by a force of magnetic repulsion.
Various variants may be envisaged by those skilled in the art. Thus, although the toothing of pinion 6 is shown as cylindrical, in a variant with axially oriented teeth, the toothings of coupling wheel 10, of pinion 6 and of wheel 8 may advantageously be conical in a first variant, and flat and ring-shaped in a second variant. In this latter case, the toothings may be of the Breguet type, namely saw-teeth ensuring reliable driving in a given direction of rotation, or in the shape of an isosceles triangle for driving in both directions of rotation of the coupling wheel. It is thus clear that a coaxial system may be provided between the coupling wheel and an input wheel or an output wheel, of the type presented in the prior art, with a friction coupling or a coupling with flat annular toothings. Various variants may also be envisaged in such a case. In particular, it will be noted that bar 30 and the bearing that it carries (notably jewel hole 28) are not indispensable, as the coupling wheel could be guided in rotation by other means. By way of example, such guiding in rotation may be achieved by elements acting on circular lateral surfaces of the coupling wheel, either on its toothing, on a lower pivot in a lower bearing (i.e. on the side of magnetic structure 34) or on an intermediate annular part between the plate comprising the coupling toothing (or possibly a friction joint) and a lower pivot.
The pivoting may also be achieved by a ball bearing type device also ensuring an axial connection (i.e. during axial translations) between the coupling wheel and the switching member. It will also be mentioned that, although the coupling wheel is arranged in the Figures for coupling two wheel sets in the coupled state of the mechanism in question, it is also possible for the coupling wheel to carry an indicator or a cam which is actuated depending on whether or not the coupling wheel is meshed with a mobile input element as a function of the angular position of the control member. Finally, it will be noted that guiding in rotation only on the lower side of the coupling wheel and an axial connection may be achieved by a lower magnetic bearing of the type described in the variant presented below.
In the variant of
This third embodiment is advantageous since switching device 4C is more compact than the two preceding embodiments.
Star 20 may be actuated by a lever or an element sliding through a lateral aperture provided in plate 50C. It will be noted that projecting portions 52C of switching element 12C, defining the axial uncoupling position of this switching member, move into abutment against the upper surface of base/stop 14C.
As particular variants, the following specific features may be mentioned:
It will be noted that the second embodiment may advantageously be implemented in a timepiece according to the third embodiment.
As indicated previously, the control member can be actuated by a user via an actuation device such as a push-piece. Other actuation devices known to those skilled in the art may be envisaged. Thus, in other embodiments, these actuation mechanisms may be automatically actuated, especially periodically by another mechanism of the timepiece, i.e. by an actuation mechanism of the timepiece that cooperates with the switched mechanism according to the invention. The invention can be applied to mechanical timepiece movements and also to timepieces having electromechanical parts. Thus, the device for actuation of the control member may have an electromechanical motor.
Finally, although the various embodiments represented in the Figures all concern switching devices with a switching member formed by a shuttle-like element subjected to general to-and-fro motions along a vertical axis, it will be noted that other embodiments may be envisaged within the scope of the present invention, in particular switching devices with a switching member formed by an element pivoting about a horizontal axis, i.e. in the general plane of the control member and thus orthogonal to its axis of rotation. By way of example, this pivoting element is a lever or pivoting part including one portion, on the side of its pivot axis, that carries the second magnetic structure. The pivoting element is arranged such that the second magnetic structure, notably formed by a bipolar magnet, is subjected to a movement along an arc of a circle whose vertical dimension is greater than its horizontal dimension. Thus, the portion bearing the second magnetic structure is subjected, according to the present invention, to a translatory motion in both directions between two stable axial positions when the control member is rotated step-by-step into its distinct angular positions.
Number | Date | Country | Kind |
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16177616.6 | Jul 2016 | EP | regional |