Driver for display elements.

Abstract

To provide a driving device for display element which can start the jump of the display to a stated and prescribed position of another display element without distinguishing or substantially distinguishing between the normal operation mode and the correction mode of a timepiece.SOLUTION: A driving device for display element for displaying the number associated with the time or derived from the time includes: a cam 3 which is designed so as to rotate around a first axis A3 and drive the motion of the display element, and includes an apex 3b; a lever 4 which rotates around a second axis A4; and a spring which is designed to return the lever 4 to contact the cam 3. The angle α is formed between the straight line that passes through the apex 3b, especially the contact point between the farthest point 30b from the first axis A3 and the lever 4, and the first axis A3 and the straight line that passes through the first axis A3 and the second axis A4 within a plane vertical to the first axis A3 and the second axis A4. The angle α is equal to or less than 70°.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The invention relates to a drive device for a display element. The invention also relates to a calendar system or module comprising said device. The invention also relates to a clock movement comprising said device or said system or said module. Finally, the invention relates to a timepiece comprising said device or said system or said module or said movement.

[0002] In particular, the invention relates to a drive device for instantaneously changing a display from one value of a number related to or derived from a time, for example a date or an hour, to another value. [Background technology]

[0003] Generally, devices are known having a drive member consisting of a pawl fixed to a cam, which cooperates with an energy store so that it can drive instantaneously a tooth row of a display member over at least one angular step, said tooth row being angularly indexed by a jumper. The energy store usually consists of elastic return means cooperating with a lever which, under the effect of said elastic return means, abuts against the side of the cam and is able to overcome, under the effect of a restoring torque of said elastic means, the torque generated by said jumper upon an instantaneous change of the display from one value of a number related to or derived from the time to another value.

[0004] The time of an instantaneous change of the display from one value of a number related to or derived from the time to another depends on several parameters, such as the coefficient of friction between the elements involved in the drive, in particular the means for pivoting the drive cam and the elements constituting the accumulator, so that the time of an instantaneous change varies depending in particular on the speed of the drive cam relative to the frame of the watch.

[0005] For this reason, in the case of a calendar mechanism, the time of the instantaneous change of the date can vary depending on the speed of the various gear trains of the movement in which the calendar mechanism is mounted. In a conventional time display mode, the speed of the driving cam is clearly defined by the speed of the hour train of the movement which drives said cam. In the time setting mode, however, for example, the speed of the driving cam is variable depending on the speed of the time setting gear train which also drives said cam. For this reason, the time of the instantaneous change of the date can vary slightly depending on the operating mode of the movement. For this reason, a date jump can be performed when the watch, in particular the hour and minute hands, are not exactly pointing to midnight. Similarly, in the case of a watch with jumping hours, a jump of the hour display can be performed when the watch, in particular the minute hand, is not exactly pointing to zero minutes.

[0006] This is because in practice it is tricky to clearly define the location of the cam profile apex that initiates, for example, a date jump, and in practice the apex is closer to a plane, and especially to a curved surface, rather than a point or an edge, due to the way the cams are manufactured and especially finished. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent Application Publication No. 1746470 [Patent Document 2] European Patent Application Publication No. 2015146 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the invention is to provide a drive device for a display element, making it possible to improve the devices known from the prior art. In particular, the invention proposes a drive device for a display element, whose operation is optimized with regard to reliability and precision. In particular, the invention proposes a drive device for a display element, capable of initiating a jump of the indication of another display element to a defined and predetermined position without, or substantially without, distinction between the normal operating mode and the correction mode of the timepiece. [Means for solving the problem]

[0009] According to the invention, a drive device according to the invention is defined in claim 1.

[0010] Various embodiments of the device are based on claims 2 to 12 is defined as:

[0011] According to the invention, a clock calendar system or module according to the invention comprises the following claims: 13 is defined as:

[0012] An embodiment of the clock calendar system or module is defined in claim 14 is defined as:

[0013] According to the invention, the clock movement according to the invention is 15 is defined as:

[0014] According to the invention, the watch according to the invention comprises the following claims 16 is defined as:

[0015] The accompanying drawings show, by way of example, an embodiment of a watch according to the invention. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of a timepiece immediately before a date jump. [Diagram 2]FIG. 2 is a detailed view of a first example of a lever and cam of a drive mechanism for a calendar display element, just prior to a date jump. [Diagram 3] FIG. 3 is a detailed view of an example of a cam for a driver for a calendar display element. [Figure 4] FIG. 4 is a schematic diagram of the first embodiment of the timepiece immediately after a date jump. [Diagram 5] FIG. 5 is a detailed view of a first example of levers and cams of the drive mechanism for the calendar display elements in a temporary configuration during a date jump. [Figure 6] FIG. 6 is a graph illustrating the principles of optimizing the profile of a cam in a driver for a calendar display element. [Figure 7] FIG. 7 is a schematic diagram of a second embodiment of the timepiece immediately before a date jump. [Figure 8] FIG. 8 is a detailed view of a second example of a lever and cam of a drive for a calendar display element in a temporary configuration during a date jump. [Figure 9] FIG. 9 is a detailed view of the cam of FIGS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A first embodiment of a watch 400 is described below with reference to figures 1 to 5. The watch is for example a watch, in particular a wristwatch. The watch comprises a watch movement 300. The watch movement may be a mechanical movement, in particular an automatic movement. The watch movement may alternatively be electronic.

[0018] The movement may include a clock calendar system 200 or a clock calendar module 200 .

[0019] The movement 300 or the clock calendar system 200 or the clock calendar module 200 comprises a drive 100 for a display element 10 for displaying numbers related to or derived from the time of day.

[0020] The clock, clock movement, clock calendar system 200 or clock calendar module 200 includes a display element 10 for displaying numbers related to or derived from time of day.

[0021] Numbers relating to or derived from time of day may include, or may specifically be, a year indicator, a month indicator, a day indicator, a date indicator, an hour indicator, or a minute indicator.

[0022] The display element may be or may include a disk with a number and / or alphabet and / or alphanumeric indicia, in particular a disk cooperating with an aperture. Alternatively, the display element may be an indicator such as a hand, in particular a hand cooperating with a graduated ring. The display element preferably pivots on a frame of the watch, of the watch movement, of the watch calendar system 200 or of the watch calendar module 200.

[0023] A driver 100 for a display element 10 for displaying numbers related to or derived from time of day, comprising: - a cam 3 designed to pivot about a first axis A3 and to drive the movement of the display element 10, the cam 3 including an apex 3b; a lever 4 pivoted about a second axis A4; a spring 5 designed to return the lever 4 into contact with the cam 3; Includes.

[0024] The cam 3 preferably pivots on a frame of the timepiece, of the timepiece movement, of the timepiece calendar system 200 or of the timepiece calendar module 200 .

[0025] The lever 4 preferably pivots on a frame of the timepiece, of the timepiece movement, of the timepiece calendar system 200 or of the timepiece calendar module 200 .

[0026] The drive device 100 comprises an energy accumulator 5, preferably a spring, and a drive movable part 1 provided with a drive member or pawl 2 fixed to a cam 3 which cooperates with the energy accumulator 5 via a lever 4, the drive pawl 2 being capable of instantaneously (or in a fraction of a second) driving the display element 10, in particular the tooth row 10a of the display element 10, in angular steps which are angularly indexed by the beak 20a of a jumper 20.

[0027] The driving armature 1 also comprises a toothed wheel 6 which is connected to the hour train 7 of the basic movement and which performs one complete rotation in 24 hours during conventional operation of the movement. Said toothed wheel 6 is also connected to a correcting or time-setting gear train 8 which is able to drive said toothed wheel 6 during a correcting or time-setting operation at a speed which is not predefined and depends on the setting habits of the wearer. The toothed wheel 6 comprises a long notch 6a, one of the ends of which is intended to drive the cam 3 and the driving pawl 2 via a pin 9 fixed to the cam. Thus, the cam 3 and the pawl 2 on the one hand and the toothed wheel 6 on the other hand can be driven at different rotational speeds.

[0028] The energy accumulator comprises, for example, a spring 5 cooperating with a lever 4. The lever 4 comprises a roller 4a, in particular a roller 4a pivoted on the lever about an axis A4a. The axes A4a and A3 are preferably parallel. The lever is designed such that the roller 4a is pressed against a side or profile of a cam. The action of the lever 4 on the cam 3 makes it possible to drive in rotation the cam 3 and the pawl 2, which in turn drives the display element 10. This action of the lever 4, brought about by the spring 5, makes it possible to overcome the torque generated by the jumper 20 during the actuation of the display element 10.

[0029] For example, via a pin 9 cooperating with one end of a long notch 6a, the gear 6 carries the cam 3 to store the energy required for a sudden displacement of the pawl 2 so that the pawl exerts a brief action on the display element 10 to cause an instantaneous jump of the display element 10. The required energy is stored by means of a spring 5 attached via a first part 3a of the profile of the cam 3 and via a lever 4. The lever 4 engages the cam 3 immediately before a change in the position of the display element 10, i.e. immediately before a jump of the display element to change the information it shows. 3 The cam 3 is in contact with an area 3b at one end of the portion 3a, which includes the apex 3b of the profile of the cam 3, i.e. the point 30b which is the point of the cam furthest from the axis A3 of rotation of the cam 3. The area 3b may for example be in the form of a curved or circular portion 3b, which includes the point 30b which is the furthest from the axis A3 of rotation of the cam 3. Alternatively, the area 3b may be reduced to the point 30b which is the furthest from the axis A3 of rotation of the cam 3. 3 The movement of the pawl 2 and the display element 10 takes place in a fraction of a second as the spring 5 restores its stored energy, which makes it possible to transmit a sudden rotational movement, via the lever 4 and its roller 4a, to the cam 3 and to the pawl 2, when the roller 4a passes through the area 3b to cooperate with the second part 3c of the profile of the cam 3.

[0030] The relative movement between pawl 2 and cam 3 on the one hand and gear wheel 6 on the other hand is made possible by the degree of freedom provided by the notch 6a. Alternatively, said degree of freedom may be provided by a "freewheel" type solution arranged between pawl 2 and cam 3 on the one hand and gear wheel 6 on the other hand.

[0031] When a jump of the display is performed, the pawl 2 is preferably held positioned in the tooth row 10a by the lever 4, and the roller 4a is pressed against the third part 3d of the profile of the cam 3, which takes the form of a recess (as shown in figures 3 and 4). The pawl 2 thus positioned allows the display element 10 to be braked, avoiding any risk of a double jump of the display.

[0032] Thus, area 3b constitutes a transition area between parts 3a and 3c of cam 3 (as shown in Figures 2 and 3).

[0033] Before the contact point of the lever with the cam exceeds the area 3b, the cam 3 is driven, via the gear 6, under the influence of one or the other of the gear trains 7, 8, relative to the lever 4 and the spring 5. Once the area 3b is exceeded, the cam is driven under the influence of the restoring force of the spring 5 and the lever 4. In other words, the area 3b constitutes a transition area where the torque applied by the lever to the cam 3 changes from positive to negative and passes through zero.

[0034] In order to minimise the sensitivity of the drive to variations due to friction between the parts involved within the drive, and to define as clearly and reproducibly as possible the time of the instantaneous change of the date, research by the inventors has revealed that it is desirable to maximise the variation in torque imparted by the lever to cam 3 over a given angular range of rotation of the cam.

[0035] In other words, it is desired to maximize the derivative of the torque applied by the lever to the cam with respect to the rotation of the cam, dC3 / dγ, where: C3 is the torque applied to the cam by the lever, or the torque of cam 3, γ is the rotation angle of the cam 3 around the first axis A3.

[0036] For this purpose, the variation of the ratio between the torque C3 of the cam 3 and the torque C4 of the lever 4 for a given rotation γ of the cam 3 must be maximized as much as possible, as long as the lever 4, and in particular the roller 4a, is in contact with the area 3b.

[0037] Furthermore, the ratio C3 / C4 turns out to be proportional to the ratio of the lengths A3P / A4P, where P is the intersection of the reaction force F between the roller 4a and the section 3b of the cam 3 with the center line A3A4 connecting the axis of rotation A3 of the cam 3 with the axis of rotation A4 of the lever 4, the reaction force F being optionally rotated through a friction angle with respect to the perpendicular of the tangent point N. Thus, a given increase in the torque C3 of the cam 3 when it is driven corresponds to a displacement of the intersection point P on the center line A3A4.

[0038] The angle α is defined in a plane perpendicular to the first and second axes A3, A4, between the apex 3b of the cam 3, in particular the point 30b of the cam 3 farthest from the axis A3, the contact point between the lever 4, a first line passing through the first axis A3, and a second line passing through the first axis A3 and the second axis A4.

[0039] More specifically, in the particular embodiment shown in the figures, an angle α can be defined between the line segments [A3 30b] and [A3 A4] when the reaction force F occurs at the moment when the roller 4a contacts the point 30b of the cam 3. More specifically, the angle α in question is the angle that partially characterizes the triangle formed by the points A3, A4, and 30b at the moment when the roller 4a contacts the point 30b of the cam 3 (see FIG. 2).

[0040] When the vertex 3b is a feature of the surface 3b, the angle α can be defined between the line segment [A3A4] and a line passing through the axis A3, the center of curvature A3b of the surface 3b or the vertex 3b, and the central axis A4a of the roller 4a (FIG. 2). In the particular case where the vertex 3b is a curved surface or a circular part 3b, the angle α can be defined between the line segment [A3A4] and a line passing through the axis A3, the center A3b of the circular part 3b, and the center A4a of the roller 4a (FIG. 2).

[0041] Of course, the contact between the lever 4 and the cam 3 may also be made directly, independent of the roller 4a. For example, the lever 4 may include a contact surface intended to cooperate directly with the cam 3. This contact surface may have, for example, a centre of curvature equivalent to the centre A4a of the roller 4a.

[0042] Research by the inventors has determined that as the angle α decreases, the angle γ of cam rotation required to cause displacement of the node P also decreases.

[0043] A second embodiment of a timepiece including a second embodiment of a drive unit 100* is shown in Figures 7 and 8 and will be described below.

[0044] FIG. 6 shows a comparison between a first embodiment 100, in which the components are arranged at an angle α of 70°, and a second embodiment 100*, in which the components are arranged at an angle α* of approximately 40°, substantially less than 70°, where the position of the axes A3, A4 is common to both embodiments. Each solid line shows the direction of the force F before and after a given rotation γ, γ* of the cam of the drive device 100 and 100*, respectively. It can be seen that with exactly the same displacement of the point P to a given position P' on the center line A3A4, the vector of the force F of the first embodiment of the device 100 must rotate through an angle β that is larger than the angle β* of the second embodiment of the device 100*. Thus, for exactly the same torque variation, γ>γ*.

[0045] For this reason, it is desirable to minimize the angle α.

[0046] The patent literature discloses examples of drives in which the angle α has a value of approximately 90°. It can be seen that, unless there is friction where the rollers are guided, the fluctuations in the torque of the cam are minimal for an angle α close to 90°.

[0047] As an example, US Pat. No. 6,299,633 relates to an improved driver for a display. Figure 1 of the document shows an obtuse angle α of approximately 98°. As a further example, US Pat. No. 6,299,633 relates to a driver for a display designed to facilitate quick correction of the display. Figure 1 of the document shows an obtuse angle α of approximately 110°. There is no teaching in these documents that encourages minimizing the value of the angle α.

[0048] For this reason, in an embodiment of the drive device of the present invention, the angle α is, in a plane perpendicular to the first and second axes A3, A4: ○ The contact point between the apex 3b of the cam 3, in particular the point 30b farthest from the first axis A3, and the lever 4; and 〇 1st axis A3 - A first line passing through - a second straight line passing through the first axis A3 and the second axis A4; It is formed between.

[0049] The angle α is the convex angle between the first and second straight lines.

[0050] The angle α may be less than or equal to 70°, or less than or equal to 65°, or less than or equal to 60°, or equal to or substantially equal to 57°.

[0051] As mentioned above, a second embodiment of a watch 400* is described below with reference to figures 7 and 8. The watch is for example a watch, in particular a wristwatch. The watch comprises a watch movement 300*. The watch movement may be a mechanical movement, in particular an automatic movement. The watch movement may alternatively be electronic.

[0052] The movement may include a clock calendar system 200* or a clock calendar module 200*.

[0053] The movement 300* or the clock calendar system 200* or the clock calendar module 200* comprises a second embodiment of a driver 100* for a display element for displaying numbers related to or derived from a time of day.

[0054] A clock, clock movement, clock calendar system 200* or clock calendar module 200* includes a display element for displaying numbers related to or derived from time of day.

[0055] In the second embodiment, the drive preferably differs from the first embodiment only in the value of the angle α, which in the second embodiment is equal to 57°.

[0056] Such an embodiment advantageously makes it possible to maximize dC3 / dγ For example, the configuration shown in Figures 7 and 8 has a torque variation at the cam that is three times larger than that of the configuration shown in Figures 1 to 5.

[0057] In the second embodiment, elements having the same structure and / or function as elements in the first embodiment are identified by the same reference numerals followed by "*".

[0058] Whatever the embodiment or variant of the drive, when the lever 4 contacts the apex 3b of the cam, in particular when the roller 4a contacts the area 3b, in particular the circular surface 3b, dC3 / dγ is preferably greater than or equal to 110 μNm per angle of rotation of the cam, or dC3 / dγ is greater than or equal to 150 μNm per angle of rotation of the cam, or dC3 / dγ is greater than or equal to 200 μNm per angle of rotation of the cam.

[0059] Whatever the embodiment or variant of the drive, the lever and the spring may be two separate parts, as in the first embodiment shown in Figures 1 to 5. Alternatively, whatever the embodiment or variant of the drive, the lever and the spring may be formed of one and the same part, as in the second embodiment shown in Figures 7 and 8.

[0060] Whatever the embodiment or variant of the drive, the angle α is greater than or equal to 30°, or greater than or equal to 35°, or greater than or equal to 40°, which makes it possible to obtain a sufficient overall performance of the drive. In particular, studies by the inventors have shown that a too small angle α leads to an excessive friction torque at the cam 3. For this reason, α is determined in such a way as to make it possible to obtain a sufficient overall performance of the drive and at the same time to solve the addressed technical problem.

[0061] Whatever the embodiment or variant of the drive, the lever preferably comprises a roller 4a. Thus, contact between the lever 4 and the cam 3 is via the roller 4a. Said roller is advantageously movable, in particular rotatable, with respect to the remainder of the lever. Thus, the roller can roll over the contour of the cam. Alternatively, the roller may be attached in a fixed manner to the remainder of the lever. The roller may be made of a hard material, for example synthetic ruby, which minimizes friction with the cam. The roller preferably has a radius of 1 mm or less.

[0062] Whatever the embodiment or variant of the drive, the apex 3b may be a portion of a cylinder with a radius of less than 0.1 mm. The cam may have at least one concave surface 3a, 3c adjacent to the apex, or two concave surfaces 3a, 3c on either side of the apex. More preferably, the apex 3b of the cam 3 is limited by bending zones 30a, 30c of the portions 3a and 3c, respectively, as shown in Figure 9. Such a design allows better control of the circular portion forming the cam apex 3b, regardless of the manufacturing method of the cam, and especially regardless of the finishing method of the cam.

[0063] Whatever the embodiment or variant, the drive comprises a drive gear 6, in particular a 24-hour wheel 6, and a connection providing a degree of freedom between the drive gear and the cam. The connection may be of the type having a pin 9 cooperating with a long notch 6a, designed to fix the cam and the drive gear. Alternatively, the connection may be of the freewheel type, designed to fix the cam and the drive gear.

[0064] Whatever the embodiment or variant, in addition to the improvements mentioned above, the design and arrangement of the cam 3 and the lever 4 make it possible to provide a drive device 100 that is particularly compact in the main plane of the device, i.e. in the plane perpendicular to the first and / or second axis. Preferably, the distance between the second axis A4 and the contact point of the lever with the cam or the distance between the second axis A4 and the axis A4a is not more than 4 times the maximum radius of the cam or the distance between the first axis A3 and the point 30b, or not more than 3 times the maximum radius of the cam or the distance between the first axis A3 and the point 30b, or not more than 2.5 times the maximum radius of the cam or the distance between the first axis A3 and the point 30b. [Explanation of symbols]

[0065] 2 Claws 3. Cam 4 Lever 5. Spring 10 Display Elements 100 Drive unit

Claims

1. A driver (100) for a display element (10) for displaying numbers related to or derived from time, comprising: a cam (3) designed to pivot about a first axis (A3) and drive the movement of said display element (10), said cam (3) including an apex (3b); A lever (4) that pivots about a second axis (A4); a spring (5) designed to return the lever into contact with the cam; Including, The angle (α) is the angle at which the vertex (3b) and the lever (4) come into contact in a plane perpendicular to the first and second axes. the contact point between said apex (3b) and said lever (4); and The first axis (A3) A straight line passing through A straight line passing through the first axis (A3) and the second axis (A4) It is formed between The angle (α) is equal to or greater than 30° and equal to or less than 60°, said device comprising a drive gear (6) and a connection providing a degree of freedom between said drive gear (6) and said cam (3), A driver for a display element for displaying numbers related to or derived from time of day.

2. characterised in that the connection providing the degree of freedom between the driving gear (6) and the cam (3) comprises a type of connection having a pin (9) cooperating with a notch (6a) and that the driving gear carries the cam by cooperating with one end of the notch and the pin.

2. The apparatus of claim 1.

3. The angle (α) is 35° or more, or 40° or more; 3. Apparatus according to claim 1 or 2.

4. said lever (4) comprises a roller (4a) intended to come into contact with said cam (3); 4. Apparatus according to any one of claims 1 to 3.

5. A driver (100) for a display element (10) for displaying numbers related to or derived from time, comprising: a cam (3) designed to pivot about a first axis (A3) and drive the movement of said display element (10), said cam (3) including an apex (3b); A lever (4) that pivots around a second axis (A4); a spring (5) designed to return the lever into contact with the cam; Including, said lever (4) comprises a roller (4a) intended to come into contact with said cam (3); The angle (α) is the angle at which the apex (3b) and the roller (4a) of the lever (4) come into contact. a straight line passing through the first axis (A3) and the second axis (A4); A straight line passing through the center (A4a) of the roller (4a) and the first axis (A3); is defined as the angle between The angle (α) is equal to or greater than 30° and equal to or less than 60°, said device comprising a drive gear (6) and a connection providing a degree of freedom between said drive gear (6) and said cam (3), A driver for a display element for displaying numbers related to or derived from time of day.

6. characterised in that the connection providing the degree of freedom between the driving gear (6) and the cam (3) comprises a type of connection having a pin (9) cooperating with a notch (6a) and that the driving gear carries the cam by cooperating with one end of the notch and the pin.

6. The apparatus of claim 5.

7. The roller (4a) is mounted on the lever so as to pivot about a third axis (A4a); 7. Apparatus according to claim 5 or 6.

8. The roller (4a) has a radius of 1 mm or less.

8. Apparatus according to any one of claims 5 to 7.

9. The apex (3b) is a circular surface (3b) having a radius of less than 0.1 mm.

9. Apparatus according to any one of claims 1 to 8.

10. The cam has at least one concave surface (3a) adjacent to the apex (3b), or the cam (3) has two concave surfaces (3a, 3c) on either side of the apex.

10. Apparatus according to any one of claims 1 to 9.

11. the cam comprises at least one display element tab (2), and / or the number related to or derived from the time of day comprises a date of a clock calendar; 11. Apparatus according to any one of claims 1 to 10.

12. the distance between the second axis (A4) and the contact point of the lever (4) with the cam (3) is less than or equal to 4 times the maximum radius of the cam (3) or the distance between the first axis (A3) and the apex (30b), or is less than or equal to 3 times the maximum radius of the cam (3) or the distance between the first axis (A3) and the apex (30b), or is less than or equal to 2.5 times the maximum radius of the cam (3) or the distance between the first axis (A3) and the apex (30b); 12. Apparatus according to any one of claims 1 to 11.

13. A clock-calendar system or module (200) comprising a device according to any one of claims 1 to 12.

14. A display element comprising a display disc (10), 14. A system or module according to claim 13.

15. A clock movement (300) comprising a system or module according to claim 13 or 14 and / or a device according to any one of claims 1 to 12.

16. A watch (400) comprising a watch movement (300) according to claim 15, and / or a system or module according to claim 13 or 14, and / or a device according to any one of claims 1 to 12.

Images