The invention relates to a linkage mechanism for a horological mechanism, arranged for a movement transmission between an actuator and a receiver.
The invention also relates to a horological mechanism, including an actuator and a receiver, and at least one such linkage mechanism, arranged for a movement transmission between the actuator and the receiver.
The invention also relates to a horological movement, including at least one such horological mechanism, and/or at least one such linkage mechanism.
The invention also relates to a watch, including at least one such horological movement, and/or at least one such horological mechanism, and/or at least one such linkage mechanism.
The invention relates to the field of horological mechanisms, and in particular display mechanisms and complication mechanisms.
The movement transformation inside a horological mechanism requires a large volume, which cannot be allocated to complication housing, and results in a loss of energy efficiency, which affects the power reserve of the timepiece, in particular a watch.
The invention suggests making the movement transformation mechanisms as flat as possible, even though they have to include two or three parallel levels in some cases, and to find a solution to reduce frictions, by limiting drive contacts to what is strictly necessary, while including a minimum of rubbing components which are always detrimental to the overall efficiency.
To this end, the invention adapts to horological mechanisms some principles of linkage mechanisms well known in heavy mechanics or in general mechanics. Nonetheless, the aim is not to create more frictions than those suppressed, at the pivots, articulations, guides and other slides.
Thus, the invention introduces into control mechanisms, for example display or winding control, flexible guides, whose horological applications have primarily concerned oscillators hitherto.
Hence, the invention aims to use flexible guides which enable movement transformations according to the principles of Hoeckens, Chebyshev, Roberts, Klann, linkage mechanisms and the same, which will be illustrated hereinafter.
It is important to understand that, although the movement of these mechanisms is generally performed in the plane, in two directions (in x and y), these articulations have only one degree of freedom. A particular point of the mechanism, like the point M in
The transformation of known mechanisms in the form of articulated bars is possible with guides and articulations in the form of a flexible guide, which eliminates losses.
Thus, the invention relates to a linkage mechanism for a horological mechanism, arranged for a movement transmission between an actuator and a receiver, according to claim 1.
The invention also relates to a horological mechanism, including an actuator and a receiver, and at least one such linkage mechanism, arranged for a movement transmission between the actuator and the receiver.
The invention also relates to a horological movement, including at least one such horological mechanism, and/or at least one such linkage mechanism.
The invention also relates to a watch, including at least one such horological movement, and/or at least one such horological mechanism, and/or at least one such linkage mechanism.
Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the appended drawings, where:
For particular drive mechanisms, a linkage mechanism with four bars is known, a main bar of which is fixed, and includes two main articulations, distinct from each other; each of these main articulations carries a secondary bar at a first end, and each secondary bar is articulated at its second end, by a secondary articulation, to a tertiary bar. Thus, each of these secondary articulations describes an imposed closed path, equivalent to a single degree of freedom, even though this degree of freedom is neither linear nor circular.
By convention, the main bar will be referred to hereinafter as “fixed structure”, it may in particular be a plate, or a bridge, or another structural element of a horological movement or of a watch case, the secondary bars that are articulated to this fixed structure by main articulations will be referred to as “arms”, the other bars will then be called according to their kinematic distance from the fixed structure, for example tertiary bar, quaternary bar, each articulated to the bar (or to the arm) the furthest upstream in this kinematic chain, through an articulation bearing the name of this bar (or this arm) the furthest upstream: for example, a tertiary bar is articulated by a secondary articulation to a secondary bar or arm; and a quaternary bar is articulated by a tertiary articulation to a tertiary bar. Thus, when a N-bar mechanism is mentioned, one of these N bars consists of the fixed structure.
Thus, a four-bar mechanism generally includes a main bar or fixed structure, and includes two main articulations; each of these main articulations carries a secondary bar at a first end, and each secondary bar is articulated at its second end, by a secondary articulation, to a tertiary bar, or is articulated to the other one. Thus, each of these secondary articulations describes an imposed closed path, equivalent to a single degree of freedom, even though this degree of freedom is neither linear nor circular.
Such a four-bar mechanism is used, for example, for driving perforated film in a cinema projector. Similarly, bus windscreen wipers are each mounted on the tertiary bar of a deformable parallelogram.
More generally, a four-bar mechanism includes four rigid bodies, generally articulated together by rotating connections such as ball-joint connections or pivots. These rotating connections may be replaced, in monolithic structures as used in watchmaking, by necks which provide enough angular freedom of one bar relative to another, in the same plane, or by flexible blades or flexible blade assemblies.
These articulated guide systems allow performing movements that are sometimes complex.
The best-known examples are the deformable parallelogram, used in particular for bus windscreen wipers, and the pantograph.
The use of main bars with different lengths enables the execution of differentiated movements, like on passenger vehicles where the movement and stroke of the driver's and passenger's windscreen wipers are different.
The quadrilateral plane mechanisms consist of deformable quadrilaterals, the bars forming the sides of which are connected together by real or virtual pivot connections such as flexible pivots with crossed flexible blades in projection, or the same.
The raise-and-lower mechanism of a wooden horse or of a merry-go-round is guided by a deformable parallelogram. A deformable parallelogram allows carrying out a circular translational movement; this allows preserving the orientation in space, in particular with respect to the horizontal plane, of a manipulated object.
A crank-connecting rod-oscillator mechanism allows transforming an alternating movement into a continuous rotational movement, or vice versa. It is well known for driving foot-operated sewing machines: the action of the user on the pedal generates an oscillating movement of the pedal, which drives a rotating crank, for driving the sewing machine.
A pantograph mechanism allows performing a homothety on a movement, and amplifying or reducing the amplitude of a movement.
A Watt parallelogram is a crossed parallelogram, which allows obtaining a particular guidance, along an imposed curve, and which is called pseudo-linear guidance. Thus, on a wagon suspension, the axle support is suspended to the structure of the wagon by two articulated bars, parallel to each other and at different distance with respect to the rail, each connected by a primary articulation to the wagon and by a secondary articulation to the axle box, and thus, the path of the centre of the wheel relative to the wagon follows an S-shaped curve which is almost linear in its central portion.
Another mechanism intended to perform a pseudo-linear movement is a three-bar mechanism, called Chebyshev linkage, which forms a crank-connecting rod-piston system. One of the secondary articulations is replaced by a slide mechanism: the end of a secondary bar slides on the other secondary bar which is a load-bearing one, for example in the form of a trunnion which travels in an oblong slot, or a pad in a slide, or the same, the tertiary bar is then no longer necessary. A point of the load-bearing secondary bar describes a repetitive closed curve. With a particular adjustment of the lengths, a portion of this closed curve could be a straight line. Chebyshev so-called lambda mechanism (because of its shape) is a four-bar mechanism which converts rotational movement into an approximate rectilinear movement, with approximately constant speed over a portion of the path from the exit point. The tertiary bar is extended outside the two secondary articulations, and a point distant from these two secondary articulations follows, over a portion of its stroke, a rectilinear path, and returns via a curved path to its starting point. Hence, it is advantageous for any retrograde type horological display. This mechanism requires the possibility of a continuous rotation on one of the primary articulations, of the crank type, which limits its use to particular cases because it is not entirely planar.
The Hoeckens mechanism, with three bars, is close to Chebyshev linkage, and also enables the conversion of a rotational movement into a substantially rectilinear movement over a large portion of its stroke. A first articulation to the fixed structure carries a connecting rod, driven in a circular movement, and which is articulated with a long bar which slides in a slide which is itself articulated at a second point of the fixed structure.
This mechanism is used in medical robotics, like the previous one, an example of application of which could be read in the doctoral thesis of Mathieu Joinie-Maurin, with the University of Strasbourg on Sep. 2, 2012, pages 69 and the next ones.
There are more accurate yet more complex devices, such as the Peaucellier-Lipkin device, which is an articulated system allowing transforming a rectilinear movement into a circular movement, and vice versa, and is based on the geometric principle of the inversion of a circle, and it includes seven rigid rods. It is actually possible to solve the problem of the rectilinear movement with fewer, the minimum being five rods like in Hart inverter is similar but requires only five rods to achieve a substantially equivalent result.
The Roberts mechanism also converts a rotational movement into an approximate linear movement. The tertiary bar is the base of an isosceles triangle, whose two sides with the same length have the same length as the secondary bars, and the vertex of this isosceles triangle opposite to the base follows a rectilinear movement on the line of the main articulations, or parallel to this line, when one of the secondary bars, or the base, is animated by an alternating rotational movement.
The Klann mechanism is a planar mechanism designed to avoid an obstacle on a path, for example to simulate the pace of a legged animal and replace the wheel. The mechanism is composed by a leg which comes into contact with the ground, a crank, two lever arms, and two connecting rods, all connected by pivot connections. The proportions of each of the connections in the mechanism are defined to optimise the linear movement of the foot during half of the rotation of the crank. The remainder of the rotation of the crank enables the foot to be raised to a predetermined height before returning to the starting position and repeating the cycle. Two mechanisms coupled together to the crank and out of phase by half a cycle enable the chassis of a vehicle to move parallel to the ground. The kinematics of the Klann mechanism is based on mechanical connections which impart the relative movement to each of the bars. It converts the rotational movement into a linear movement. The document U.S. Pat. No. 6,260,862 describes such a mechanism. Although with a more complex kinematics than the mechanisms with three or four bars, and although requiring three levels, the Klann mechanism has the advantage of being able to generate a complex path guaranteeing the absence of collision with an obstacle, and that being so, in a perfectly repetitive way.
It should be understood that all these mechanisms have a common characteristic: at least one particular point always follows the same closed path, therefore according to a single degree of freedom along this path. More particularly, for some of them, at least one portion of this path is substantially linear, or linear. Often, the rest of the path is close to an arc of a circle, or of a parabola, or the same.
The invention suggests using the properties of some of these mechanisms for controlling some horological functions, in particular display functions. Indeed, modern micro-machining techniques and the implementation of “LIGA”, “MEMS” or similar type processes allow obtaining monolithic components grouping together complex functions, and in particular within oscillators. The rotary connections, such as ball-joint connections or pivots, of conventional mechanics could be replaced, in these monolithic structures as used in watchmaking, by necks which provide enough angular freedom from one bar relative to another, in the same plane.
Many of the above-described mechanisms are well suited for a planar execution, which is advantageous in watchmaking technique. Other mechanisms, driven in rotation continuously or not, require a crank in a secondary plane, which is parallel to a main plane in which all of the articulations other than those of the crank are located. Other ones require more levels, like the Klann mechanism illustrated in
Thus, the invention relates to a linkage mechanism 100 for a horological mechanism, arranged for a movement transmission between an actuator and a receiver.
According to the invention, this linkage mechanism 100 includes a fixed structure 10, relative to which a carrier 9 is movable according to a single degree of freedom under the action of such an actuator, this carrier 9 being connected to the fixed structure 10 by at least one flexible guide 50, each of said carrier 9 and said fixed structure 10 being more rigid than each flexible guide 50.
More particularly, this carrier 9 is movable according to a single degree of freedom, other than a pivoting one, and so that each point of this carrier 9 follows a path other than circular.
The carrier 9 moves under the effect of the actuator, guided according to the degree of freedom only by the flexible guide 50. In particular, when the carrier does not transmit any movement to the receiver, only the flexible guide 50 enables the carrier 9 to follow the degree of freedom. In other words, no other portion of the linkage mechanism 100 or of the horological mechanism acts on the carrier 9 to make it follow the degree of freedom. The actuator just provides the actuation force to the carrier 9, and the flexible guide 50 orients the carrier 9 along the degree of freedom.
When the carrier 9 is in contact with the receiver to transmit the movement thereto, the receiver does not affect the degree of freedom defined by the flexible guide 50. Thus, the receiver does not act on the unique degree of freedom.
By its flexibility, the flexible guide 50 defines the pathway that the carrier 9 follows, and which corresponds to the unique degree of freedom. For example, the unique degree of freedom is a closed pathway around a surface or a volume, which is preferably partially curvilinear. More particularly, the carrier 9 is connected to the fixed structure 10 by a plurality of flexible guides 50.
More particularly, the only connections between the carrier 9 and the fixed structure 10 are of the flexible guide type: the carrier 9 is connected to the fixed structure 10 only by a flexible guide 50 or several flexible guides 50.
More particularly, at least one flexible guide 50 is planar, and includes flexible necks 51, with a smaller section than the elements that are adjacent thereto, and forming articulations, and/or includes flexible blades 5, 6, 52, with a smaller section to the elements that are adjacent thereto, and forming articulations. The figures illustrate, without limitation; straight flexible blades, it is clear that these flexible blades could be curved, bent, or else adopt complex shapes, for example zig-zag like or other.
Even more particularly, each flexible guide 50 is planar, and includes flexible necks 51, with a smaller section than the elements that are adjacent thereto, and forming articulations, and/or includes flexible blades 5, 6, 52, with a smaller section than the elements that are adjacent thereto, and forming articulations.
And in particular, this linkage mechanism 100 includes at least two arms 1 and 2, which are articulated to the structure 10 at two distinct points, these arms 1 and 2 being arranged to kinematically cooperate with each other, or with a tertiary bar 12 or a tertiary structure 120, such as a non-deformable triangle 121, or a deformable quadrilateral 122, or other. Advantageously, this tertiary bar 12 or this tertiary structure 120 forms this carrier 9.
The linkage mechanism 100 includes a first main articulation 11 between the structure 10 and a first arm 1, and a second main articulation 21 between the structure 10 and a second arm 2, and:
either the first arm 1 includes, at a distance from the first main articulation 11, a translational guide with flexible connections or a sliding element 18 arranged to cooperate slidably and in an articulated manner with a complementary sliding element 28 which includes, at a distance from the second main articulation 21, the second arm 2 forming the carrier 9, as shown in
or the linkage mechanism 100 includes, at a distance from the first main articulation 11, a first secondary articulation 110 between the first arm 1 and the carrier 9, and, at a distance from the second main articulation 21 and from the first secondary articulation 110, a second secondary articulation 210 between the second arm 2 and the carrier 9, or between the second arm 2 and an operating bar 4 articulated with the carrier 9.
In one variant, the kinematics according to Chebyshev lambda mechanism is ensured by a substitute for conventional articulations:
In one variant, as shown in
In one variant, as shown in
In different variants, and in particular those illustrated by
In this variant of
In one variant, at least one flexible guide 50 includes at least two parallel planar levels, and includes in each level flexible blades 5, 6, 52, with a smaller section than the elements that are adjacent thereto, and whose directions are crossed and whose projection, on a plane parallel to the levels, of the intersection of these directions defines a virtual pivot axis and an articulation, as shown in
More particularly, the carrier 9, the structure 10, and at least one flexible guide 50 are coplanar. Even more particularly, the carrier 9, the structure 10, and each flexible guide 50 are coplanar.
In one variant, the carrier 9 is a third bar.
In one variant, the carrier 9 is a polygonal rigid structure, like in the embodiment of
In an advantageous variant, the carrier 9 includes, at a distal end 90, a hook or a finger or a tooth for driving a receiver.
In many variants, the first arm 1 or the second arm 2 is arranged to be driven by an actuator. But the drive by the actuator could also be done at an intermediate bar of the linkage mechanism 100.
In a particular variant of a Klann mechanism, the third bar 3 is arranged to be driven by an actuator.
More particularly, and as shown in
More particularly, at least one flexible guide 50 includes a pivot with two separate crossed blades, or a pivot with two integral crossed blades, or an RCC pivot with two orthogonal blades, or an RCC pivot with 4 necks, or at least two blades at least locally parallel, or a translational guide with flexible collar connections. A linear flexible guide of the type of
More particularly, the linkage mechanism 100 is a composite mechanism including at least one flexible guide 50 made of silicon and/or silicon oxide, or of a micro-machinable material shaped by a “LIGA” or “MEMS” or process or the same, this flexible guide being mechanically fastened to the carrier 9 and to the structure 10 by a pinned and/or screwed and/or glued and/or pinched connection, or another mechanical connection known to the watchmaker.
More particularly, the linkage mechanism 100 is a monolithic mechanism.
Advantageously, the path T of the distal end 90 includes at least one linear or substantially linear section T1. More particularly, the entire path T of the distal end 90 is linear or substantially linear. More particularly, the path T of the distal end 90 forms an eight-light shape, which could be very flattened, depending on the lever arms imposed on the linkage mechanism, and the crossing portion of the loops of the eight-light shape is very close to a linear stroke.
More particularly, the path T of the distal end 90 includes a linear or substantially linear section corresponding to a first stroke T1 of the distal end 90 in a first direction, and a concave curve joining the ends of the section and corresponding to a second stroke T2 of the distal end 90 in the second direction opposite to the first direction.
The invention also relates to a horological mechanism 500, including an actuator and a receiver, and at least one such linkage mechanism 100, arranged for a movement transmission between the actuator and the receiver.
In one variant, the carrier 9 is arranged to drive a receiver by direct contact, or through a push-piece or a lever, in particular by its distal end 90.
In one variant, the actuator is arranged to exert a continuous force on the linkage mechanism 100, over the entirety of a control stroke, for an adequate stroke of the receiver.
In one variant, the actuator is arranged to exert an impulse on the linkage mechanism 100, to transmit an adequate impulse to the receiver.
In one variant, the actuator is secured to one of the elements of a flexible guide 50 or articulated with one of the elements of a flexible guide 50.
The actuator may be in different forms:
a rotational drive mechanism, in particular an element of a geartrain (for example in
a rake drive mechanism, as shown in
a cam drive mechanism, as shown in
In a particular embodiment, the linkage mechanism 100 is a Hoeckens mechanism arranged to transform a rotation imparted by the actuator into a linear retrograde movement of the receiver.
In a particular embodiment, the linkage mechanism 100 is a Roberts mechanism arranged to transform a rotation imparted by the actuator into a linear retrograde movement of the receiver, the distal end 90 of the carrier 9 being a vertex of a triangle 121 whose other vertices are articulated to articulated arms 1, 2, that the linkage mechanism 100 includes.
In a particular embodiment, the linkage mechanism 100 is a Klann mechanism arranged to transform a continuous rotation imparted by the actuator into a periodic drive push on a toothing or a bearing surface that the receiver includes.
In a particular embodiment, the linkage mechanism 100 is a Chebyshev lambda mechanism arranged to transform a continuous rotation imparted by the actuator into a periodic drive push on a toothing or a bearing surface that the receiver includes.
In a particular embodiment, the linkage mechanism 100 is a Chebyshev linkage mechanism arranged to transform a rotation imparted by the actuator into a linear retrograde movement of the receiver.
The invention also relates to a horological movement 1000, including at least one such horological mechanism 500, and/or at least one such linkage mechanism
The preferred embodiment of these mechanisms includes flexible guides 50, the horological mechanism 500 or the linkage mechanism 100 may of course also include at least one conventional rotational or translational guide.
The invention also relates to a watch 2000, including at least one such horological movement 1000, and/or at least one such horological mechanism 500, and/or at least one such linkage mechanism 100.
In the same manner, it is easy to implant a Roberts mechanism according to
To sum up, the mechanisms according to the invention make the most of the space available in a watch, and improve the overall efficiency by minimising frictions.
The advantage of applying the invention to display mechanisms is the transformation of a rotational movement into a translational movement for a linear display with a single degree of freedom.
The advantage of the application of the invention to actuation mechanisms is the possibility of actuating a toothing with kinematics allowing for a minimum of friction. Indeed, in the case of the prior art, the actuator comes into contact with a tooth and circumvents it. Contact is necessary to circumvent the tooth. In general, when the carrier is a hook or the same, the back of this hook, i.e. the portion opposite to that which includes a bearing surface intended to modify the position of the toothing, rubs against the tooth, before the bearing surface drives the tooth, there are then large areas of friction and wear, which are detrimental to the efficiency of the mechanism, and to its resistance over time. On the other hand, in the case of the invention, the flexible guide guides the actuator to circumvent the tooth without contact, the kinematics of the linkage mechanism actually enabling a substantially radial approach, then the actuator comes into contact with the tooth only to actuate it. Hence, the friction areas are reduced, as well as the energy lost by friction. The details of
The flexible guides, as used in these applications, have a great potential in watchmaking as they have the following properties and advantages:
absence of wear;
absence of lubrication;
absence of seizing;
absence of dust emission;
absence of hysteresis;
accuracy and repeatability;
control and accuracy of the repetitive path;
absence of backlash in the system.
Number | Date | Country | Kind |
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20178321.4 | Jun 2020 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2021/064900 | 6/3/2021 | WO |