Patent Grant
10768577
This application claims priority from European Patent Application No. 17177642.0 filed on Jun. 23, 2017, the entire disclosure of which is hereby incorporated herein by reference.
The present invention concerns a push-piece winding button control device for a portable object of small dimensions comprising a frame, a control stem that is mounted to pivot about a longitudinal axis and axially movable relative to the frame between at least a first position (“T0”), which is transitory (or in other words unstable), and a second position (“T1”) which is stable. The control device further includes a cam path, which has a longitudinal cam profile, and a cam follower arranged to cooperate with the longitudinal cam path. The cam path is arranged to move concurrently with the control stem when the latter is moved axially. The cam follower is mounted inside the frame and is arranged to be elastically returned against the cam path. The cam path includes a recess, which defines the stable position of the control stem, and a ramp-shaped profile portion which rises from the recess towards the transitory position.
There are already known push-piece winding button control devices. European Patent No EP1930794, for example, describes a magnetic push-piece winding button control device for timepieces. According to this document, the push-piece winding button control stem has a profiled section which is essentially formed of two grooves and one inclined part. The profiled section is arranged to cooperate with the two arms of a split elastic ring in order to index the position of the push-piece winding button control stem by holding or returning the latter in or to a selected axial position. The control stem, which is symmetrical with respect to a determined plane passing through a longitudinal axis, is free to rotate between the two arms of the split elastic ring. By pressing or pulling out the push-piece winding button, the wearer of the watch can choose to make the control stem occupy three different, predefined positions. A stable first position, called the rest position, in which the arms of the split elastic ring are engaged in a first groove; a stable second position, called the pulled-out position, in which the arms of the split elastic ring are engaged in a second groove; and finally a transitory position, called the pushed-in position, in which the arms of the split elastic ring cooperate with the inclined part of the profiled section, such that, under the combined action of the pressure from the arms of the split elastic ring on the inclined part of the inclined section and the return force exerted by a spring, the control stem returns to the rest position as soon as the wearer of the watch releases pressure on the push-piece winding button.
Implementing a push-piece winding button control device like the one just described above is not, however, without a certain number of problems. In particular, one drawback lies in the fact that, in order to machine the cam path in a section of the control stem, the diameter of the control stem must be relatively large, which makes the use of such a control stem quite difficult, or even impossible, particularly in the field of wristwatches, where it is undesirable to have to machine large diameter holes in the case middle for passage of a control stem, in particular due to the thickness of the case middle.
Another example of such a control stem is illustrated in
Thus, through cooperation between the elastic arms of a spring and a cam path which is integral with the cylindrical portion of a control stem, it is advantageously possible to define, for example, three stable positions of the control stem which each correspond to the setting of a given function. The drawback of this solution lies, however, in the fact that, in order to machine the cam path in the cylindrical portion of the control stem, the diameter of the cylindrical portion of the control stem must be relatively large, which makes the use of such a control stem quite difficult, or even impossible, especially in the field of wristwatches, where it is undesirable to have to machine large diameter holes in the case middle, in particular due to the thickness of the case middle.
It is an object of the present invention to overcome the aforementioned problem of the prior art by providing a push-piece winding button control device conforming to the definition given in the preamble and wherein the pressure of the cam follower on the profile portion forming a ramp is sufficient to reliably return the stem to the stable position from the transitory position, even with a stem whose diameter is sufficiently small to be suitable for use in the field of horology, for example.
To this end, the present invention provides a push-piece winding button control device according to claim 1 annexed hereto.
According to the invention, the at least one cam path with which the at least one cam follower cooperates, is formed in a position indexing plate, which is arranged to be integral in translation with the control stem, but which remains stationary when the stem is pivoted. It will be understood that this feature means that the cam path, which allows the position of the control stem to be indexed, is transferred from the actual control stem to a position indexing plate which is machined separately from the control stem. Such an indexing plate is relatively thin and constantly maintains the same orientation, whereas, when the cam path is arranged on the control stem, this requires increasing the diameter of the control stem and therefore the height of the middle part of the portable object, so that the portable object is thicker, which it is sought to avoid, particularly in the field of timepieces.
According to an advantageous variant of the invention, when the push-piece winding button is pressed from the stable position, the reaction force that must be overcome to push in the push-piece winding button is high until the cam follower passes over a transition point. Beyond that point, the reaction force that has to be overcome is considerably lower. The abrupt drop in force on crossing the transition point produces a click sensation. It will be understood that such a click cannot be obtained with a known type of push-piece winding button arranged to be returned to the rest position by the force exerted by a return spring. Indeed, the force exerted by a spring can only increase monotonically as the spring is compressed and cannot pass through a point after which the force drops abruptly. Conversely, with a push-piece winding button according to the invention, the reaction force that must be overcome to enable the cam follower to climb the ramp profile portion, is determined by the slope of the ramp. Thus, according to the present advantageous variant, the ramp profile portion includes a first part that extends between the recess and a point of transition, and whose slope is steep. The profile portion further includes a second part that extends in a more moderate slope than the first part from the transition point towards the transitory position.
According to other features of preferred embodiments of the invention which form the subject of dependent claims:
Other features and advantages of the present invention will appear more clearly from the following detailed description of an example embodiment of a control device according to the invention, this example being given solely by way of non-limiting illustration with reference to the annexed drawing, in which:
The present invention proceeds from the general inventive idea which consists in transferring a position indexing mechanism for a stem controlling at least two electronic and/or mechanical functions of a portable object of small dimensions, such as a timepiece, from this control stem to a plate that is machined separately from said control stem. By doing so, it is possible to reduce the diameter of the control stem and thus at the same time reduce the thickness of the middle part of the portable object, such as a timepiece. This result is achieved as a result of the fact that, instead of being structured straight onto the control stem, the indexing mechanism, which typically takes the form of at least one, and preferably two cam paths cooperating with an elastic member, is made in a thin plate which forms a separate part from the control stem and which is mechanically coupled to the latter. Since the control stem is devoid of its indexing mechanism, its diameter can be reduced, and due to its small thickness, the position indexing plate of the invention does not entail any significant increase in the dimensions of the control stem of the invention.
In all that follows, the back-to-front direction is a rectilinear direction which, with respect to a bottom of the portable object, extends horizontally along longitudinal axis of symmetry X-X of the control stem from the external actuation push-piece winding button towards the interior of the portable object equipped with the control device. Thus, the control stem will be pushed from back to front and will be pulled from front to back. Further, the vertical direction z is a direction that extends perpendicularly to the horizontal plane in which the control stem extends.
At a rear end 6, which will be located outside the portable object once the latter is equipped with a control device 1, control stem 4 will receive an actuation push-piece winding button 8 (see
At a front end 10, which will be located inside control device 1 once the latter is assembled, control stem 4 has, for example, a square section 12 and receives in succession a magnetic assembly 14 and a smooth bearing 16.
Magnetic assembly 14 includes a bipolar or multipolar magnetized ring 18 and a support ring 20, on which magnetized ring 18 is fixed, typically by adhesive bonding (see
Smooth bearing 16 defines (see
It is noted that the square hole 26 provided in first section 22a of support ring 20 is extended towards the front of control device 1 by an annular hole 30 whose second internal diameter D4 is fitted onto third external diameter D5 of smooth bearing 16. Support ring 20 is thus fitted for free rotation on smooth bearing 16 and moves into axial abutment against smooth bearing 16, which ensures the perfect axial alignment of these two components and makes it possible to correct problems of concentricity that may be caused by a sliding pinion type coupling.
It is observed that, for axial immobilization thereof, smooth bearing 16 is provided on its outer surface with a circular collar 32 which projects into a first groove 34a and into a second groove 34b, respectively arranged in lower frame 2 (see
It is important to note that the magnetic assembly 14 and smooth bearing 16 described above are mentioned only for illustrative purposes. Indeed, smooth bearing 16, for example made of steel or brass, is arranged to prevent control stem 4, for example made of steel, rubbing against lower and upper frames 2 and 36, and causing wear of the plastic material of which these two lower and upper frames 2 and 36 are typically made. However, in a simplified embodiment, it is possible to envisage not using such a smooth bearing 16 and arranging for control stem 4 to be directly carried by lower frame 2.
Likewise, magnetized ring 18, and support ring 20 on which magnetized ring 18 is fixed, are intended for the case where rotation of control stem 4 is detected by a local variation in the magnetic field induced by the pivoting of magnetized ring 18. It is, however, entirely possible to envisage replacing magnetic assembly 14, for example with a sliding pinion which, according to its position, will for example control the winding of a mainspring or the time-setting of a watch equipped with control device 1.
It is also important to note that the example of control stem 4 provided on one part of its length with a square section is given purely for illustrative purposes. Indeed, in order to drive magnetic assembly 14 in rotation, control stem 4 may have any type of section other than a circular section, for example triangular or oval.
Lower frame 2 and upper frame 36, the combined assembly of which defines the external geometry of control device 1, are for example, of generally parallelepiped shape. Lower frame 2 forms a cradle which receives control stem 4 (see
Lower frame 2 further includes, towards the back, a second receiving surface 40, whose semicircular profile is centred on longitudinal axis of symmetry X-X of control stem 4, but whose diameter is greater than that of control stem 4. It is important to understand that control stem 4 only rests on second receiving surface 40 at the stage when the assembled control device 1 is being tested prior to incorporation in the portable object. At this assembly stage, control stem 4 is inserted into control device 1 for test purposes and extends horizontally, supported and axially guided by smooth bearing 16 at its front end 10 and via second receiving surface 40 at its rear end 6. However, once control device 1 is incorporated in the portable object, control stem 4 passes through a hole 42 arranged in the middle part 48 of the portable object in which it is guided and supported (see
Third and fourth clearance surfaces 44a and 46a of semicircular profile are also provided in lower frame 2 and complementary clearance surfaces 44b and 46b (see
As seen in
As visible in
Two apertures 70 exhibiting an approximately rectangular contour are provided in guide arms 62 of position indexing plate 58. These two apertures 70 extend symmetrically on either side of longitudinal axis of symmetry X-X of control stem 4. The sides of the two apertures 70 closest to longitudinal axis of symmetry X-X of control stem 4 have a cam path 72 of substantially sinusoidal shape, formed of a first and a second recess 74a, 74b separated by a peak 76.
The two apertures 70 provided in guide arms 62 are intended to receive a cam follower 78. According to a preferred but non-limiting embodiment of the invention, cam follower 78 takes the form of a positioning spring 80 whose two ends 81 are received in apertures 70 of guide arms 62 (see
It was mentioned above that position indexing plate 58 is coupled in translation to control stem 4, but that it is free with respect to control stem 4 in the vertical direction z. It is thus necessary to take steps to prevent position indexing plate 58 disengaging from control stem 4 in normal conditions of use, for example under the effect of gravity. To this end (see
Displacement limiting spring 88 includes a substantially rectilinear central portion 90 from the ends 81 of which extend two pairs of elastic arms 92 and 94. These elastic arms 92 and 94 extend on either side of central portion 90 of displacement limiting spring 88, upwardly away from the horizontal plane in which central portion 90 extends. As these elastic arms 92 and 94 are compressed when upper frame 36 is joined to lower frame 2, they impart elasticity to displacement limiting spring 88 along vertical direction z. Between the pairs of elastic arms 92 and 94 there is also provided one pair, and preferably two pairs, of stiff lugs 96 which extend perpendicularly downwards on either side of central portion 90 of displacement limiting spring 88. These stiff lugs 96 which come into abutment on lower frame 2 when upper frame 36 is placed on lower frame 2, ensure that a minimum space is provided between position indexing plate 58 and displacement limiting spring 88 in normal operating conditions of control device 1.
Displacement limiting spring 88 guarantees the disassemblability of control device 1. Indeed, in the absence of displacement limiting spring 88, position indexing plate 58 would have to be made integral with control stem 4 and, consequently, control stem 4 could no longer be dismantled. If control stem 4 cannot be dismantled, the movement of the timepiece equipped with control device 1 cannot be dismantled either, which is inconceivable, particularly in the case of an expensive timepiece. Thus, when control device 1, formed by joining lower and upper frames 2 and 36, is mounted inside the portable object and control stem 4 is inserted into control device 1 from outside the portable object, control stem 4 slightly lifts position indexing plate 58 against the elastic force of displacement limiting spring 88. If control stem 4 continues to be pushed forwards, there comes a moment when position indexing plate 58 drops into groove 56 under the effect of gravity. Control stem 4 and position indexing plate 58 are then coupled in translation.
A disassembly plate 98 is provided to allow disassembly of control stem 4 (see
From its stable rest position T1, control stem 4 can be pushed forwards into an unstable position T0 or pulled out into a stable position T2. These three positions T0, T1 and T2 of control stem 4 are indexed by cooperation between position indexing plate 58 and positioning spring 80. More precisely (see
From its stable rest position T1, control stem 4 can be pushed forwards into an unstable position T0 (see
When they reach a transition point 116, ends 81 of arms 86 engage on a second ramp profile 118 which extends first ramp profile 114 with a second slope β smaller than first slope α of first ramp profile 114. At the instant that ends 81 of arms 86 of positioning spring 80 cross transition point 116 and engage on second ramp profile 118, the force required from the user to continue moving control stem 4 drops sharply and the user feels a click indicating the transition of control stem 4 between position T1 and position T0. As they follow second ramp profile 118, arms 86 of positioning spring 80 continue to move slightly away from their rest position and tend to try to move towards each other again under the effect of their elastic return force which opposes the thrust force exerted by the user on control stem 4. As soon as the user releases pressure on control stem 4, arms 86 of positioning spring 80 will spontaneously move back down first ramp profile 114 and lodge again inside first recesses 74a of the two apertures 70 provided in guide arms 62 of position indexing plate 58. Control stem 4 is thus automatically returned from its unstable position T0 to its stable first position T1.
First and second contact springs 120a and 120b which, on the one hand, participate in returning control stem 4 from its unstable position T0 to its stable first position T1, are compressed and housed inside a first and a second cavity 122a and 122b provided in lower frame 2. These first and second contact springs 120a and 120b could be helical contact springs, strip-springs or other springs. The two cavities 122a, 122b preferably, but not necessarily, extend horizontally. Because the two contact springs 120a, 120b are installed in the compressed state, their positioning precision is dependent on the manufacturing tolerance of lower frame 2. The manufacturing precision of lower frame 2 is higher than the manufacturing precision of these two first and second contact springs 120a, 120b. Consequently, the precision of detection of position T0 of control stem 4 is high.
As visible in
First and second contact springs 120a, 120b are of the same length. However, preferably, one of the first and second cavities 122a, 122b will be longer than the other, in particular to take account of tolerance problems (the difference in length between the two cavities 122a, 122b is several tenths of a millimetre). Thus, when control stem 4 is pushed forwards into position T0, finger 66a of position indexing plate 58, which is lined up with first contact spring 120a housed inside the first, longest cavity 122a, will come into contact with and start to compress first contact spring 120a. Control stem 4 will continue to move forward and second finger 66b of position indexing plate 58 will come into contact with second contact spring 120b housed inside the second, shortest cavity 122b. At that moment, position indexing plate 58 will be in contact with first and second contact springs 120a, 120b and the electric current will flow through position indexing plate 58, which allows the closure of the electrical contact between the first two contact springs 120a, 120b to be detected. It is noted that fingers 66a, 66b of position indexing plate 58 move into abutment contact with first and second contact springs 120a, 120b. There is thus no friction or wear when control stem 4 is pushed forwards into position T0 and closes the circuit between first and second contact springs 120a, 120b. It is also noted that, the difference in length of first and second cavities 122a and 122b ensures that closure of the electrical contact and entry of the corresponding command into the portable object equipped with control device 1 occur only after a click is felt.
When the two fingers 66a, 66b of position indexing plate 58 are in contact with first and second contact springs 120a, 120b, first contact spring 120a housed inside first, longest cavity 122a is in a compressed state. Consequently, when the user releases pressure on control stem 4, this first contact spring 120a relaxes and forces control stem 4 to return from its unstable pushed-in position T0 to its stable first position T1. The first and second contact springs 120a, 120b thus act simultaneously as electrical contact parts and means for elastic return of control stem 4 into its stable first position T1.
From stable first position T1, it is possible to pull control stem 4 backwards into a stable second position T2 (see
It will be noted that, in the case of stable position T2, fingers 66a, 66b of position indexing plate 58 also come into abutment contact with third and fourth contact springs 130a, 130b, thereby avoiding any risk of wear from friction. Further, third and fourth contact springs 130a, 130b are capable of bending when fingers 66a, 66b of position indexing plate 58 collide therewith, and therefore of absorbing any lack of precision in the positioning of position indexing plate 58.
Preferably, but not necessarily, third and fourth contact springs 130a, 130b are arranged to work in flexion. Indeed, with contact springs 130a, 130b whose diameter is constant, fingers 66a, 66b of position indexing plate 58 come into contact with contact springs 130a, 130b over a large surface close to their points of attachment in lower frame 2 and upper frame 36. The proximity of the contact surface to the attachment points of contact springs 130a, 130b induces shearing stresses in contact springs 130a, 130b which may lead to premature wear and breakage of the latter. To overcome this problem, contact springs 130a, 130b have, preferably substantially at mid-height, an increase in diameter 134 which comes into contact with fingers 66a, 66b of position indexing plate 58 when control stem 4 is pulled into its stable position T2 (see
In
The free portion 144 of flexible printed circuit sheet 128 is connected to the rest of flexible printed circuit sheet 128 by two strips 152, which allow free portion 144 to be folded around the assembly of upper frame 36 and lower frame 2, and then folded down against a lower surface 112 of lower frame 2, so that inductive sensors 150 penetrate two housings 156 provided in lower surface 112 of lower frame 2. Thus positioned inside their housings 156, inductive sensors 150 are precisely located under magnetized ring 18, which ensures reliable detection of the direction of rotation of control stem 4. Once free portion 144 of flexible printed circuit sheet 128 has been folded down against lower frame 2 (see
It goes without saying that the present invention is not limited to the embodiment that has just been described and that various simple modifications and variants can be envisaged by those skilled in the art without departing from the scope of the invention as defined by the annexed claims. In particular, the dimensions of the magnetized ring may be extended so that it corresponds to a hollow cylinder. It will be understood, in particular, that position indexing plate 58 may define only two distinct positions, namely two stable positions or one stable position and one unstable position, or it may define three or more distinct positions, namely at least three stable positions or at least two stable positions and one unstable position.
More precisely, the first stable position T1-1 corresponds to the position in which ends 81 of arms 86 of positioning spring 80 project into first recesses 74a-1 of the two apertures 70-1 provided in guide arms 62 of position indexing plate 58. From this first stable position T1-1, control stem 4 can be pulled back into a second stable position T2-1. During this movement, ends 81 of arms 86 of positioning spring 80 will elastically deform to pass from first recesses 74a-1 to second recesses 74b-1, crossing peaks 76-1 of the two apertures 70-1 provided in guide arms 62 of position indexing plate 58.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17177642 | Jun 2017 | EP | regional |
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| 3832843 | Wuthrich | Sep 1974 | A |
| 5305291 | Kamens | Apr 1994 | A |
| 6203190 | Stotz | Mar 2001 | B1 |
| 6896403 | Grau | May 2005 | B1 |
| 20010053109 | Ehrsam | Dec 2001 | A1 |
| 20040136275 | Kaelin | Jul 2004 | A1 |
| 20160116306 | Ferri et al. | Apr 2016 | A1 |
| Number | Date | Country |
|---|---|---|
| 1 435 633 | Jul 2004 | EP |
| 3 015 925 | May 2016 | EP |
| Entry |
|---|
| European Search Report dated Oct. 19, 2017 in European Application 17177642.0 filed on Jun. 23, 2017 (with English Translation of Categories of Cited Documents). |
| Number | Date | Country | |
|---|---|---|---|
| 20180373204 A1 | Dec 2018 | US |
