EP1996368B1 - Method of controlling a probe for reading the groove in a spectacle frame rim and corresponding reading apparatus - Google Patents

Abstract

The present invention relates to a process for reading the contour of the groove (10A) of a spectacle frame (10) rim comprising a step of contacting a probe (8) against the groove (10A) and a step of sensing the groove (10A) by sliding or rolling said probe (8) along the groove (10A), the position of the probe (8) being determined and the velocity of the probe (8) comprising first, second and third components (VP, VR, VZ). According to the invention, the first component (VP) of the velocity of the probe (8) is controlled dynamically to vary, continuously or in steps, in the course of reading as a function of at least one or both of the second and third components (VR, VZ) of the velocity of the probe (8).

Description

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

The present invention relates generally to the field of eyewear and more specifically the probing of the bezel of a frame rimmed glasses.

It relates more particularly to a method of reading the outline of the bezel of a spectacle frame circle comprising a step of contacting a probe against the bezel and a step of probing the bezel by sliding or rolling said probe along the bezel, the position of the probe being determined and the probe speed comprising first, second and third components.

It also relates to a device for reading the outline of the bezel of a spectacle frame circle which comprises means for holding the frame, a feeler, means for determining the position of the feeler and means for controlling a first component of the speed of the probe, and which is adapted to implement the steps of the contour reading method.

The method finds a particularly advantageous application by its application to glasses with elongated or strongly arched frames.

TECHNOLOGICAL BACKGROUND

• la lecture du contour des drageoirs des cercles de la monture sélectionnée par le porteur, c'est-à-dire du contour des rainures qui parcourent l'intérieur de chaque cercle de la monture,
• le centrage de chaque lentille qui consiste à déterminer la position qu'occupera chaque lentille sur la monture afin d'être convenablement centrée en regard de la pupille de l'oeil du porteur de manière à ce qu'elle exerce convenablement la fonction optique pour laquelle elle a été conçue,
• le palpage de chaque lentille qui consiste à déterminer les coordonnées de points sur chacune des faces de la lentille caractérisant la géométrie du contour des lentilles, puis,
• le détourage de chaque lentille qui consiste à usiner ou à découper son contour à la forme souhaitée, compte tenu des paramètres de centrage définis, avec, en fin d'usinage, le biseautage qui consiste à réaliser sur la tranche de la

The technical part of the optician's profession is to mount a pair of ophthalmic lenses on a frame selected by a wearer. This assembly is broken down into five main operations:

• reading the outline of the bevels of the circles of the frame selected by the wearer, that is to say the contour of the grooves that run through the inside of each frame of the frame,
• the centering of each lens which consists in determining the position that each lens will occupy on the frame in order to be properly centered facing the pupil of the wearer's eye so that it properly exercises the optical function for which it was designed,
• the probing of each lens which consists in determining the coordinates of points on each of the faces of the lens characterizing the geometry of the contour of the lenses, then,
• the trimming of each lens which consists of machining or cutting its contour to the desired shape, taking into account the defined centering parameters, with, at the end of machining, the beveling which consists in producing on the edge of the

lens a bevel to hold the lens in the bezel that includes the mount.

In the context of the present invention, we are interested in the first operation of reading the outline of the bevels of the circles of the frame. This is concretely, for the optician, palpate the inner contour of the circles of the frame of the selected glasses to precisely determine the coordinates of a plurality of points characterizing the contour of the bottom of the bezel of each circle. The knowledge of this outline allows the optician to deduce the shape that will have to present the lenses, once cut and beveled, in order to be mounted on this mount.

The objective of this operation is in particular to follow exactly the bottom of the bezel that includes the circle to read so as to memorize a precise digital image of the geometry of the bezel.

In the case of elongated frames (that is to say having a low height compared to the distance between the two attachment points of the frame legs) or strongly arched, a simple support of the probe on the bezel at constant speed along its contour does not allow to precisely record the coordinates of the points characterizing the outline of the bottom of the bezel.

The document US 6,871,158 has a bezel tracking device provided to overcome the problems of inaccuracies in the reading of the bezels due to the deformation of the frames during the passage of the probe. This device comprises in particular means for identifying the type of frame to be read and means for controlling the speed of rotation of the probe for sliding along the complete contour of the bezel. In order to refine the accuracy of the reading of the bevels, this device is adapted to determine the type of the frame to be read, then, depending on whether this type of frame is characteristic or not of a frame that can encounter problems of deformation, to control the probe in rotation at a speed depending on the type of frame, constant on the whole bezel. In order to increase the speed of reading, this device can provide for splitting the outline of the bezel into different predetermined zones in which the speed of rotation of the feeler is constant but between which it varies.

The disadvantage of such a device is that to substantially improve the reading accuracy of the bezel, it is necessary to very strongly reduce the speed of rotation of the feeler along the entire bezel, which greatly increases and detrimental to the reading time of the outline of the bezel, it is necessary to divide the outline of the bezel into different zones, in which case the applicant has noticed that there are reading. The splitting operation is further manually performed by the operator on a suitable interface, which requires experience and takes time.

Documents are also known EP 1 037 008 and US 6,325,700 contour reading apparatus according to the preamble of claim 8 and methods for reading bezel contours of eyeglass frame circles according to the preamble of claim 1.

The methods described each comprise a step of contacting the feeler against the bezel of the spectacle frame and a step of probing the bezel.

In the document EP 1 037 008 during the probing step, the effects of gravity on the probe are compensated by the actuating motors of the probe. This method thus makes it possible to improve the accuracy of the probing performed.

In the document US 6,325,700 during the probing step, the motors are controlled to vary the position of the probe according to the curvature of the bezel of the frame, so that the probe follows this bezel and does not.

OBJECT OF THE INVENTION

The present invention provides a method of fast contour reading and providing accurate results.

More particularly, it is proposed according to the invention a contour reading method as defined in the introduction, wherein the first component of the speed of the probe is dynamically controlled to vary, continuously or in steps, during reading according at least one or the other of the second and third components of the probe speed.

The probe generally has the shape of an elongate rod along a probing axis and is conventionally driven in rotation about an axis of rotation for sliding along the complete contour of the bezel.

When reading this bezel, if the mount is not strictly circular, the probing axis of the probe can not be constantly presented orthogonally to the tangent to the outline of the bezel. Therefore, the longer the frame is elongated, the more the probe is presented inclined with respect to the bezel in certain areas of the frame, particularly near the nasal and temporal areas of the frame. When the frame is strongly arched, this inclination can present in these same areas very important values.

However, the greater this inclination, the more the probe rod is subjected to bending forces. These bending forces then generate errors in the acquisition of the coordinates of the bezel insofar as the coordinates of the end of the feeler calculated by the contour reading apparatus are distorted.

Thus, thanks to the invention, when the measuring means detect that at least a second or a third component of the speed of the probe increases abruptly, which indicates that the probe departs from its ideal position orthogonal to the bezel, the control means reduce the first component of the probe speed so as to lower the bending forces to increase the accuracy of the measurements.

According to a first advantageous characteristic of the contour reading method according to the invention, the probe being provided with three degrees of freedom, the first, second and third components of the probe speed are each associated with one of the three degrees of freedom of the sensor. probe.

Advantageously, the probe rotating around an axis of rotation for its sliding along the complete contour of the bezel of the eyeglass frame circle, the first component of the probe speed is constituted by the speed of rotation of the probe around said axis of rotation.

Thus, only the speed of rotation of the probe is modified to reduce the bending forces applied to the probe so that it is easy to adapt this first component of the speed of the probe according to one or two other components of its probe. speed.

Advantageously, the second component of the speed of the probe is a transverse component of the speed of the probe axis perpendicular to the axis of rotation of the probe. In addition, the third component of the speed of the probe is an axial component of the speed of the probe axis parallel to the axis of rotation of the probe.

Advantageously, the first component of the probe speed decreases when the second and / or third component of the probe speed increases.

According to another advantageous characteristic of the contour reading method according to the invention, the second and the third components of the probe speed varying one and the other continuously each in a range of intervals interval velocities, the means of control change the first component of the probe speed when the second and / or third component of the probe speed changes interval.

The Applicant has noticed that the second and third components of the probe speed vary continuously and have high values in localized areas of the circles of the frame. Thus, the method therefore provides for varying the first component of the speed of the probe in steps such that the probe has a constant and high speed of rotation in the areas other than these localized areas of the frame, and a lower speed in these localized areas.

The present invention also provides a contour reading apparatus as defined in the introduction, wherein the determining means is adapted to determine at least one and / or the other of the second and third components of the probe speed. and the control means are capable of driving dynamically, continuously or in stages, the first component of the speed of the probe as a function of at least the second and / or third component of the speed of the probe determined by the determination means.

• le palpeur étant pourvu de trois degrés de liberté, un premier des trois degrés de liberté du palpeur est constitué par son aptitude à pivoter autour d'un axe de rotation, un deuxième des trois degrés de liberté du palpeur est constitué par son aptitude à se translater selon un axe parallèle à l'axe de rotation et un troisième des trois degrés de liberté du palpeur est constitué par son aptitude à se mouvoir par rapport à l'axe de rotation ;
• les moyens de pilotage sont aptes à piloter la première composante de la vitesse du palpeur selon le premier des trois degrés de liberté du palpeur ;
• les moyens de détermination sont aptes à déterminer la deuxième composante de la vitesse du palpeur selon le deuxième des trois degrés de liberté du palpeur ; et
• les moyens de détermination sont aptes à déterminer la troisième composante de la vitesse du palpeur selon le troisième des trois degrés de liberté du palpeur.

Other advantageous and non-limiting features of the contour reading apparatus according to the invention are the following:

• the probe being provided with three degrees of freedom, a first of the three degrees of freedom of the probe is constituted by its ability to pivot about an axis of rotation, a second of the three degrees of freedom of the probe is constituted by its ability to translate along an axis parallel to the axis of rotation and a third of the three degrees of freedom of the probe is constituted by its ability to move relative to the axis of rotation;
• the control means are able to control the first component of the speed of the probe according to the first of the three degrees of freedom of the probe;
• the determination means are able to determine the second component of the speed of the probe according to the second of the three degrees of freedom of the probe; and
• the determination means are able to determine the third component of the probe speed according to the third of the three degrees of freedom of the probe.

Advantageously, the contour reading apparatus comprises a turntable rotatably mounted about the axis of rotation relative to the mounting means of the frame, this turntable carrying a reading subassembly which comprises the movable feeler of one part in a direction parallel to the axis of rotation and secondly in a plane transverse to the axis of rotation, the reading subassembly further comprises another axis of rotation called transverse bearing axis on the surface of the turntable and a support arm which, at one of its ends, is rotatably mounted around said carrier axis and on which is embarked at the other end of said probe.

Thus, the reading subassembly pivoting about the carrier axis, the probe rod may have a very large inclination relative to the normal to the tangent to the bezel. This inclination depends in fact on the shape of the frame, but also on the angular position of the reading subassembly around the bearing axis. Consequently, the control means make it possible to control the speed of rotation of the turntable, which corresponds here to the first component of the speed of the probe, as a function of the second and third components of the speed of the probe, which makes it possible to take account of not only the shape of the frame (elongated and / or arched) but also the angular position of the reading subassembly.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

The following description with reference to the attached drawings given in As non-limiting examples, will make clear what the invention is and how it can be achieved.

• la figure 1 est une vue en perspective d'un appareil de lecture de contour recevant une monture de lunettes dont la forme des cercles est destinée à être relevée par un palpeur ;
• les figures 2 et 3 sont des vues en perspective du dessous du plateau tournant extrait de l'appareil de la figure 1, ces figures 2 et 3 permettant de voir selon deux angles différents le sous-ensemble de lecture porté par le plateau tournant ;
• la figure 4 est une vue en coupe des cercles de la monture de lunettes reçue par l'appareil de lecture de contour de la figure 1 ;
• la figure 5 est un graphique représentant le contour d'un des cercles de la monture de lunettes de la figure 4 ;
• la figure 6 est un graphique représentant la variation de l'altitude des points du contour du drageoir d'un des cercles de la monture de lunettes de la figure 4 ;
• la figure 7 est un graphique représentant la variation de la vitesse radiale du palpeur de la figure 1 lors de la lecture d'un des cercles de la monture de lunettes de la figure 4 ; et
• la figure 8 est un graphique représentant la variation de la vitesse axiale (c'est-à-dire sensiblement suivant l'axe du cercle lu, qui est ici vertical) du palpeur de la figure 1 lors de la lecture d'un des cercles de la monture de lunettes de la figure 4.

In the accompanying drawings:

• the figure 1 is a perspective view of a contour reading device receiving an eyeglass frame whose shape circles is intended to be raised by a probe;
• the figures 2 and 3 are perspective views from below the turntable extracted from the device of the figure 1 these figures 2 and 3 allowing to see according to two different angles the reading subassembly carried by the turntable;
• the figure 4 is a sectional view of the circles of the spectacle frame received by the contour reading device of the figure 1 ;
• the figure 5 is a graph representing the outline of one of the circles of the eyeglass frame of the figure 4 ;
• the figure 6 is a graph representing the variation of the altitude of the points of the outline of the bezel of one of the circles of the spectacle frame of the figure 4 ;
• the figure 7 is a graph representing the variation of the radial velocity of the probe of the figure 1 when reading one of the circles of the eyeglass frame of the figure 4 ; and
• the figure 8 is a graph representing the variation of the axial speed (that is to say substantially along the axis of the circle read, which is here vertical) of the probe of the figure 1 when reading one of the circles of the eyeglass frame of the figure 4 .

The figure 1 is a general view of a contour reading apparatus 1 as it is presented to its user. This apparatus comprises an upper cover 2 covering the entire apparatus except for a central upper portion.

The contour reading device 1 also comprises a set of two jaws 3, at least one of the jaws 3 is movable with respect to the other so that the jaws 3 can be moved closer to each other or separated from each other. form a clamping device. Each of the jaws 3 is further provided with two clamps each formed of two movable studs 4 to be adapted to clamp together a frame 10 of spectacles. The frame 10 can then be held stationary on the contour reading device 1.

In the space left visible by the upper central opening of the cover 2, a frame 5 is visible. A plate (not visible) can move in translation on this frame 5 according to a transfer axis D. On this plate is mounted rotating 6. This turntable 6 is therefore able to take two positions on the transfer axis D, a first position in which the center of the turntable 6 is disposed between the two pairs of studs 4 fixing the right circle of the mount 10, and a second position in which the center of the turntable 6 is disposed between the two pairs of studs 4 fixing the left circle of the frame 10. The right circle and the left circle of the frame are circles intended to be respectively positioned opposite the right eye and the left eye of the wearer when the latter carries said frame.

The turntable 6 has an axis of rotation B defined as the axis normal to the front face of the turntable 6 and passing through its center. The turntable 6 further comprises an oblong slot 7 in the form of an arc of a circle through which a feeler 8 has a bearing rod 8A and at its end a feeler pin 8B intended to follow by sliding or possibly rolling the contour of the frame 10 palpated.

The turntable 6 is guided in rotation about a first axis, its axis of rotation B, by three guide rollers (not shown) arranged regularly along its periphery and held on the plate 5 of the reading device of FIG. contour 1. The rotation of the plate 6 is controlled by a motor-encoder (not shown) whose output shaft is provided with a pinion meshing with a ring gear equipping the periphery of the plate 6. This motor-encoder allows a reading at any time of the angular position of the plate 6 corresponding to an angular position TETA of the probe 8.

It can be seen that in this example, the arcuate light 7 has a length approximately corresponding to the radius of the turntable 6 and extends between the center of the turntable 6 and its periphery. The circular arc described by the light 7 is centered around a carrier axis A.

After disassembly of the apparatus 1, the turntable 6 can be extracted from the frame 5. It is then as shown on the figures 2 and 3 . The perspective view of the figure 2 shows a groove 14 disposed on the edge of the turntable 6, over its entire circumference. This groove 14 cooperates with the guide rollers of the plate. The turntable 6 carries a reading subassembly 15. The figures 2 and 3 allow to see the reading subset 15 according to two different angles of view. The reading subassembly 15 comprises a bearing 16 on which is mounted a carrier shaft 17 rotatably mounted on the turntable 6. This carrier shaft 17 has as axis the carrier axis A.

With reference to the figure 2 a carrier arm 18 is mounted on the carrier shaft 17. The carrier arm 18 has at one of its ends a ring 20 allowing the carrier arm 18 to rotate about the carrier axis A and a translational movement along that axis. At its opposite end to the ring 20, the support arm 18 comprises a cylindrical support 21 on which is fixed the support rod 8A of the probe 8 so that the axis of this support rod 8A remains parallel to the carrier axis A .

This assembly allows the probe 8 to present a movement in an arc along the light 7, in a plane orthogonal to the axis of rotation B of the turntable 6, this axis of rotation B being here parallel to the axis A In addition, the probe 8 can perform an input / output movement with respect to the front face of the turntable 6, when the carrier arm 18 slides along the axis A.

In summary, the feeler 8 is provided with three degrees of freedom, including a first degree of freedom TETA consisting of the ability of the feeler 8 to rotate about the axis of rotation B through the rotation of the turntable 6, a second degree of freedom Z constituted by the ability of the probe 8 to translate along an axis parallel to the axis of rotation B by sliding the support arm 18 along the axis A, and a third degree of freedom R constituted by the ability of the feeler 8 to move relative to the axis of rotation B thanks to its freedom of movement along the arc formed by the light 7.

Each point read by the end of the probe 8 is located in a corresponding coordinate system R, TETA, Z.

The probe 8 thus has a decomposable speed in three distinct components, a first component called rotation speed VP corresponding to the speed of rotation of the turntable 6, a second component called radial velocity VR corresponding to the transverse component of the speed of the probe 8 along an axis perpendicular to the axis of rotation B and passing through the end of the probe 8, and a third component called axial speed VZ corresponding to the axial component of the speed of the probe 8 along the axis of rotation B.

The reading subassembly 15 also comprises a guide arm 22 attached to the base of the shaft 17. This guide arm 22 has a length sufficient to reach the light 7. The guide arm 22 comprises a semicircular portion toothed 26 centered on the carrier axis A. The teeth of the semicircular portion 26 mesh with an intermediate gear 27 which itself meshes with the pinion (not visible) of a motor-encoder 28 mounted on a yoke 29 which is fixed on the turntable 6. The teeth of the intermediate gear 27 have not been shown to make the drawings clearer. The guide arm 22 comprises a vertical clevis 30, arranged parallel to the bearing axis A, on which is fixed a motor-encoder 31 whose pinion 32 meshes with a rack 33 fixed on the ring 20 of the carrier arm 18. The rack 33 is arranged parallel to the carrier axis A. The teeth of the pinion 32 have not been represented for the same reasons of clarity as before.

The encoder motor 28 is therefore able to rotate the feeler 8 about the carrier axis A. It therefore allows the probe 8 to exert a force along an axis of effort E tangent to the arc described by the light 7.

The motor-encoder 31 is itself able to move the probe 8 along an axis parallel to the carrier axis A. In particular, it makes it possible to exert a so-called mass compensation torque Cz which cancels the mass of the probe 8 and the carrier arm 18 seen by the bezel 10A of the frame 10 when the bezel and the probe are in contact with each other.

The contour reading apparatus 1 further comprises means 101 for determining the position R, TETA, Z of the end of the feeler finger 8B of the feeler 8 and of its speed, in particular of its axial and radial components VZ VR.

It also comprises dynamic control means 102, that is to say in real time, the speed of the probe 8. Advantageously, only the rotational speed VP of the turntable 6 is controlled.

All of these determination means 101 and control 102 is integrated in an electronic device and / or computer 100 allowing, on the one hand, to actuate the encoder motors 28, 31, and on the other hand, recovering and recording the data transmitted by these encoder motors 28, 31. These data are here transmitted in the form of voltage slots sent by the encoder motors 28, 31 when they pivot.

The figure 4 represents the upper end of the probe 8 comprising the feeler finger 8B. This feeler finger 8B points along an axis perpendicular to the axis of the support rod 8A. It has a pointed end intended to fit into the bezel 10A of a circle of the frame 10 to raise the geometry of its outline.

When a frame 10 is disposed in the contour reading apparatus 1, each point of the contour of the bezel 10A can be defined by three spatial coordinates corresponding to the coordinates R, TETA, Z of the end of the probe 8. A point of the mount is therefore identified by its radial coordinate R separating this point from the center of the turntable 6, its angular position TETA relative to, for example, the angular position of the first point palpated, and its altitude Z.

In our case study, we are particularly interested in elongated frames (that is to say, having, once installed on the wearer's face, a low height and a large width between the two arms of the frame) and / or strongly arched with respect to the general plane of the circles of the mount 10. An example of a strongly arched mount is shown on the figure 4 .

The camber of a frame can be quantified using a curve angle J. This curve angle J corresponds to the angle formed between the general plane K of the circles of the frame 10 (vertical plane passing through the bridge) nasal connecting the two circles of the frame) and the axis L defined as being the axis passing through two distinct points of the bezel 10A (typically one located near the nasal part of the circle and the other near the part temporal circle) and having the greatest inclination relative to the general plane K of the circles of the frame 10.

Here is meant by strongly arched a mount whose curvature angle J is greater than 20 degrees.

This type of strongly arched frames 10 generally also has a twisting of the bezel 10A commonly called "pouring".

The outline of the bottom of the bezel of a circle of mount 10 has been schematized on the figure 5 . For a good understanding of Figures 6 to 8 , the contour represented on this figure 5 has been discretized into eight distinct arcs having at their ends points P1 and P2, P2 and P3 up to P8 and P1.

It will further be noted that each of the points P1, P2, P3, P4, P5, P6, P7, P8 has an altitude Z respectively denoted Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8 represented on FIG. figure 6 .

Before palpating a frame, it is possible to calibrate the contour reading apparatus 1. In particular, this calibration must make it possible to make precise measurements on the frames to be probed, whatever the shapes of these frames (large circles). or small rays, strongly arched frames ...).

To carry out this calibration, it is necessary to be able to measure and compensate the differences between, on the one hand, the theoretical kinematic model representing the kinematics of the contour reading apparatus 1, and, on the other hand, the real kinematics of the device at a given moment. It is for example important to know very precisely, in the reference system of the apparatus, the position of the end of the probe 8. The differences between the kinematic model and the reality are due to inaccuracies in the production of the parts, assembly of these parts, and changes over time (wear, shocks, temperature variations).

To calibrate the device, a standard caliber of shape is used any. The shape of this caliber on at least several tens of coordinate points MRi = (XRi, YRi, ZRi, i = 1 to N) is then measured very precisely, for example on a three-dimensional machine. In practice, 800 separate points are used. The coordinates of these measurement points are preferably stored in memory in the contour reading apparatus 1. If several calibres are used, these calibers are numbered, and these numbers are stored in memory in the apparatus, in order to avoid associating a set of measurement points with a gauge does not correspond to it.

Such a three-dimensional machine may for example be constituted by a contour reading device of the same type as that described here and shown on the Figures 1 to 3 but suitably calibrated and / or made with a structure and / or mechanical components of higher precision.

Preferably, the caliber has a geometry such that, when probing in the three-dimensional machine, the measured radius and height vary in large proportions, ideally throughout the measurement range of the contour reading apparatus. For example, the template may have a shape in two dimensions (for example an ellipse) in a plane inclined by twenty degrees relative to the horizontal.

In any case, the measuring points MRi = (XRi, YRi, ZRi) are given in a coordinate system whose X axis is the horizontal axis passing through the center of the two jaws of the three-dimensional machine, of which the Y axis is the horizontal axis perpendicular to the X axis, whose Z axis is the vertical axis perpendicular to the X and Y axes and whose origin O is located at the center of the segment connecting the centers of the two upper jaws.

We then seek to find the differences between the theoretical kinematic model and the actual kinematics of the apparatus in order to be able to measure, by means of the contour reading apparatus 1 thus calibrated, a set of approximate points MLi = (XLi, YLi, ZLi, i = 1 to N) which are closest to the set of measurement points MRi = (XRi, YRi, ZRi).

• l'angle TETAO qui correspond à la différence entre la position angulaire TETA réelle d'un point mesuré par le palpeur et la position angulaire TETA acquise par l'appareil de lecture de contour, en supposant cette différence constante ;
• l'angle PCX qui correspond au défaut de parallélisme, suivant l'axe X, entre l'axe de rotation B du plateau tournant 6 et l'axe vertical Z ;
• l'angle PCY qui correspond au défaut de parallélisme, suivant l'axe Y, entre l'axe de rotation B du plateau tournant 6 et l'axe vertical Z ;

• la distance R0 qui correspond à la différence entre le rayon réel et le rayon acquis par l'appareil de lecture de contour, que l'on suppose constante ;
• l'angle PPX qui correspond au défaut de parallélisme, suivant l'axe X, entre l'axe porteur A et l'axe vertical Z ;
• l'angle PPY qui correspond au défaut de parallélisme, suivant l'axe Y, entre l'axe porteur A et l'axe Z ;
• la distance dAB réelle entre l'axe porteur A et l'axe de rotation B du plateau tournant 6 qui diffère en pratique de la distance considérée dans le modèle théorique ; et
• la distance LBille entre l'extrémité du palpeur et l'axe porteur A qui diffère en pratique de la distance considérée dans le modèle théorique.

The parameters to be considered in order to characterize a difference between the theoretical model and the actual kinematics of the apparatus are the following:

• the angle TETAO corresponding to the difference between the actual TETA angular position of a point measured by the probe and the TETA angular position acquired by the contour reading apparatus, assuming this constant difference;
• the angle PCX which corresponds to the parallelism defect, along the axis X, between the axis of rotation B of the turntable 6 and the vertical axis Z;
• the angle PCY which corresponds to the defect of parallelism, along the axis Y, between the axis of rotation B of the turntable 6 and the vertical axis Z;

• the distance R0 which corresponds to the difference between the real radius and the radius acquired by the contour reading apparatus, which is assumed to be constant;
• the angle PPX which corresponds to the parallelism defect, along the axis X, between the bearing axis A and the vertical axis Z;
• the angle PPY which corresponds to the parallelism defect, along the Y axis, between the carrier axis A and the axis Z;
• the actual distance dAB between the carrier axis A and the axis of rotation B of the turntable 6 which differs in practice from the distance considered in the theoretical model; and
• the distance LB between the end of the probe and the carrier axis A which differs in practice from the distance considered in the theoretical model.

Of course, other parameters can be defined and calculated to refine the calibration.

It is also necessary to determine parameters not related to the calibration of the contour reading apparatus 1 but related, on the one hand, to the uncertainty of positioning of the standard gauge in the O, X, Y, Z coordinate system of the three-dimensional machine, and, on the other hand, the difference between the origins of the contour reading apparatus 1 and the three-dimensional machine. For this purpose, the difference along the X axis between a point measured on the contour reading apparatus 1 and this same point measured on the three-dimensional machine is defined by dXO. The distance along the Y axis between a point measured on the contour reading apparatus 1 and this same point measured on the three-dimensional machine is defined by dYO. The difference along the Z axis between a point measured on the contour reading apparatus 1 and this same point measured on the three-dimensional machine is defined by dZO.

Calibration is then performed according to the following steps. In a first step, the 800 measurement points of the calibration caliber are acquired and recovered using the three-dimensional machine. Then, a reading of the standard caliber is carried out by means of the contour reading apparatus 1. The parameters TETAO, PCX, R0, PPY, PPX, dAB, LBille, dXO, dYO and dZO are then searched which make it possible to minimize the difference between the two sets of points MLi and MRi. To do this, the points MLi are corrected by modifying the values of the parameters chosen, a set of MLCORRi points is deduced therefrom, and the difference between the coordinates of the points MLCORRi and MRi is calculated. As long as this difference between the points MLCORRi and MRi is not negligible (that is to say as long as the differences between their respective coordinates are not all less than predefined threshold values), the parameters are modified again. to reduce this difference.

This modification can be done empirically, parameter after parameter. It is also possible to use the well-known gradient technique associated with a difference calculation of MRi / MLCORRi points using the least squares method. We apply here the gradient technique on Diff Diff function (TETA0, PCX ... dZO) = sum [(XLCOORi -XMi) ^ 2 + (YLCOORi -YMi) ^ 2 + (ZLCOORi -ZMi) ^ 2], i = 1..N.

When the difference between the points MLCORRi and Mri falls below a predefined threshold, the optimum parameters TETA0optim, PCXoptim, R0optim, PPYoptim, PPXoptim, dABoptim, LBilleoptim, dXOoptim, dYOoptim and dZOoptim are finally obtained.

Thus, when reading the spectacle frame by the contour reading apparatus 1 (described as follows), the measured points MLi can be corrected with the optimum parameters obtained TETA0optim, PCXoptim, R0optim, PPYoptim, PPXoptim, and Aboptim. LBilleoptim.

Before starting the probing of the bezel 10A of the circle of the frame 10 whose contour is represented on the figure 5 , this frame 10 is inserted between the pads 4 of the jaws 3 so that each of the circles of the frame 10 is ready to be palpated along a path starting by the insertion of the probe between two studs 4 corresponding to the lower part of the frame 10, then following the bezel 10A of the frame 10, to cover the entire circumference of the circle of the frame 10. Following this insertion, the electronic and / or computer device 100 calibrates the mass compensation torque Cz so that the probe 8 is at equilibrium irrespective of its altitude Z with respect to the turntable 6.

In operation, the probe 8 is first inserted in the right circle of the mount 10. For this, the plate 5 on which the turntable 6 is mounted moves with the aid of a motor and a link rack (not shown) so that the center of the turntable 6 is disposed between the two pairs of studs 4 of the two jaws 3 fixing the right circle of the frame 10.

The feeler finger 8B is then automatically placed at a known altitude Z and corresponding to the altitude of the point situated at half height between two studs 4 for fixing the frame 10. In order to place the probing finger 8B at this altitude Z , the reading subassembly 15 has an on-board mechanism allowing movement of the feeler 8 parallel to the axis A. This mechanism comprises the encoder motor 31 which is adapted to arrange the ring 20, and consequently the carrier arm 18, at the desired height on the shaft 17. The probe 8 can thus have a vertical movement along the axis Z '.

The feeler finger 8B then moves in the plane of attachment of the frames 10 towards a point located between the two studs 4 for fixing the frame 10 on its lower part. For this, a joint movement of rotation about the axis A of the guide arm 22 and the support arm 18 allows the guide arm 22, driven by the motor-encoder 28, to drive itself the feeler 8 in rotation around the axis A, along the light 7.

In this initial position, when the feeler finger 8B is disposed between the two pads 4 (at a point here distinct from the point P1), the turntable 6 defines as zero the angular position TETA and the altitude Z of the end of the 8. The guide rollers of the turntable 6 are then able to rotate the reading subassembly 15 relative to the fixed frame 5, the reading subassembly 15 being embarked on the turntable 6. The motor- encoder (not shown) which drives the rollers inserted in the groove 14 not only causes rotation of the turntable 6 but also allows the electronic and / or computer device 100 to know the value of the angular position TETA (in degrees) that the feeler 8 from its initial position.

When the turntable 6 begins to rotate, the value of the angular position TETA of the probe 8 increases at a nominal speed V0. This nominal speed V0 here is 2.8 hundredths of a degree per millisecond. The probe 8 moves along the bottom of the bezel 10A and is guided according to its radial coordinate R and according to its altitude Z by this bezel 10A. The probe being inserted into the right circle of the frame 10, the probe 8 moves in the trigonometrical direction.

Preservation of the contact of the probing finger 8B with the bezel 10A is provided by the encoder motors 28,31. These last exert indeed an overall effort on the probe 8 which allows the probing finger 8B to remain in contact with the bottom of the bezel 10A.

During rotation of the turntable 6, the encoder motor 28 thus drives the turntable and also acts as an encoder to identify the successive positions of the carrier arm 18 along the light 7. The encoder motor 28 thus delivers a signal enabling the determination means 101 of the electronic and / or computer device 100 to know at all times the radial coordinate R of the feeler finger 8B with respect to the axis of rotation B of the turntable 6.

The motor-encoder 31 exerts a so-called mass compensation torque Cz intended to at least artificially cancel the weight of the assembly formed by the support arm 18 and the probe 8. The encoder motor 31 also operates simultaneously in the same manner. encoder which allows the determination means 101 of the electronic device and / or computer 100 to know the altitude Z of the probe finger 8B of the probe 8. The variation of this altitude Z (in millimeters) as a function of the angular position TETA ( in degree) of the probe 8 is represented on the graph of the figure 6 . This graph highlights in particular the significant height of the nasal and temporal parts of the frame 10.

Knowing the coordinates of the center of the turntable 6 relative to the frame 5, the electronic and / or computer device 100 can then possibly determine the coordinates of the feeler finger 8B in a fixed reference frame attached to the frame 5. It can thus store a digital image contours of the two bezels 10A circles of the frame in the same frame.

Be that as it may, the set of encoder motors 28, 31 allows the electronic and / or computer device 100 to determine the spatial coordinates R, TETA, Z of the point palpated by the probe 8 and consequently the spatial coordinates of a set of points characterizing the outline of the bottom of the bezel when the probe 8 has accurately palpated the entire contour of the bezel 10A.

According to an advantageous characteristic of the invention, the electronic and / or computer device 100 notes in particular the values of the radial coordinates R of the probed points in order to determine, with the aid of a suitable derivation software, the instantaneous radial velocity V R of probe 8 (corresponding to the transverse component of the speed of the probe 8). The evolution of this radial velocity VR (in hundredths of millimeters per millisecond) as a function of the angular position TETA of the turntable 6 (in degrees) is represented on the graph of the figure 7 for a rotation speed VP of the turntable 6 constant and equal to its nominal speed V0. In particular, the radial velocities VR of the probe 8 denoted VR1, VR2, VR3, VR4, VR5, VR6, VR7, VR8 respectively taken at points P1, P2, P3, P4, P5, P6, P7, P8 are represented.

The electronic and / or computer device 100 also records the values of the elevations Z of the probed points in order to determine, using the derivation software, the instantaneous axial speed VZ of the probe 8 (corresponding to the axial component of the speed of the probe 8 ). The evolution of this axial speed (in hundredths of millimeters per millisecond) according to the angular position of the turntable 6 (in degrees) is shown on the graph of the figure 8 for a rotation speed VP of the turntable 6 constant and equal to its nominal speed V0. Particularly represented are the axial velocities VZ of the feeler 8 denoted VZ1, VZ2, VZ3, VZ4, VZ5, VZ6, VZ7, VZ8 taken respectively at the points P1, P2, P3, P4, P5, P6, P7, P8.

Advantageously, the rotational speed VP of the turntable 6 is dynamically controlled to vary during reading as a function of the axial speed VZ and the radial speed VR of the probe 8.

It will be understood here that the radial velocity VR of the probe 8 and the variation speed of the radial coordinate R of the probed point as a function of the angular position TETA of the turntable 6 are two identical quantities. Indeed, the TETA angular position of the turntable 6 is a function of time, the radial velocity VR is mathematically related to the speed of variation of the radial coordinate R of the probed point as a function of the TETA angular position of the turntable 6. From in the same way, the axial velocity VZ of the probe 8 and the velocity variation of the altitude Z of the probed point as a function of the angular position TETA of the turntable 6 are two identical quantities. It is therefore possible to control the rotational speed VP of the turntable 6 according to one of these magnitudes.

The radial velocity V R and the axial velocity V Z of the probe 8 here and there vary each continuously in a velocity range respectively between -5 and 5 hundredths of a millimeter per millisecond and between -7 and 7 hundredths of a millimeter. millisecond. Advantageously, these two velocity domains are divided into three intervals. When the radial and axial velocities of the probe 8 remain confined in an interval without changing, the control means 102 controls the turntable 6 at a constant rotation speed VP. On the other hand, when one or other of the axial speeds VZ and radial VR change interval, the control means 102 change the rotational speed VP of the turntable 6.

• si la vitesse radiale VR du palpeur 8 dépasse en valeur absolue la valeur de 3,3 centièmes de millimètres par milliseconde ou si sa vitesse axiale VZ dépasse la valeur de 4,6 centièmes de millimètres par milliseconde, alors les moyens de pilotage 102 diminuent la vitesse de rotation VP du plateau tournant 6 à une valeur correspondant au tiers de sa vitesse nominale V0 ;
• si en revanche, la vitesse radiale VR du palpeur 8 est inférieure en valeur absolue à la valeur de 1,7 centièmes de millimètres par milliseconde et si sa vitesse axiale VZ est inférieure en valeur absolue à la valeur de 2,3 centièmes de millimètres par milliseconde, alors les moyens de pilotage 102 stabilisent la vitesse de rotation du plateau tournant 6 à sa vitesse nominale V0 ;
• sinon, les moyens de pilotage 102 stabilisent la vitesse de rotation VP du plateau tournant 6 à une vitesse correspondant à la moitié de sa vitesse nominale V0.

More precisely, the electronic and / or computer device 100 is programmed so that the value of the angular position TETA of the probe 8 increases,

• if the radial velocity VR of probe 8 exceeds in absolute value the value of 3.3 hundredths of millimeters per millisecond or if its axial velocity VZ exceeds the value of 4.6 hundredths of millimeters per millisecond, then the control means 102 decrease the rotational speed VP of the turntable 6 to a value corresponding to one third of its nominal speed V0;
• if on the other hand, the radial velocity VR of the probe 8 is smaller in absolute value than the value of 1.7 hundredths of a millimeter per millisecond and if its axial velocity VZ is smaller in absolute value than the value of 2.3 hundredths of a millimeter millisecond, then the control means 102 stabilize the speed of rotation of the turntable 6 at its nominal speed V0;
• otherwise, the control means 102 stabilize the rotational speed VP of the turntable 6 at a speed corresponding to half of its nominal speed V0.

Optionally, the measured values of radial velocity VR and axial VZ probe 8 can be filtered and smoothed by ad hoc software integrated electronic device and / or computer 100 before being compared across the aforementioned intervals.

On the example of the frame 10 whose contour is represented on the figure 5 , we notice first of all on the graph of the figure 7 that the radial velocity VR of the probe 8 exceeds, in absolute value, 1.7 hundredths of a millimeter per millisecond in an angular interval of approximately 135 degrees divided between the points P1 and P4 and between the points P6 and P7 of the contour of the bezel 10A .

Note also on the graph of the figure 8 that the axial velocity VZ of the probe 8 exceeds, in absolute value, 2.3 hundredths of millimeters per millisecond in an angular interval of about 90 degrees between the points P1 and P3 of the contour of the bezel 10A.

It is therefore useful in this example to reduce the rotational speed of the turntable 6 between the points P1 and P4 and between the points P6 and P7 of the bezel contour 10A in order to reduce the bending forces to which the probe 8 is subjected. in order to increase the accuracy of the reading of the contour defined by the bezel 10A.

It is thus possible to keep on the majority of the contour of the bezel 10A a rotational speed VP of the turntable 6 important. The time required to read the entire bezel 10A remains low while the accuracy of this reading is greatly increased.

It will be noted that, alternatively, it is possible to program the electronic and / or computer device 100 so that the rotation speed VP of the probe 8 is not limited to three programmed speeds step-by-step, but that it can to vary continuously according to a preprogrammed function associating with each measured axial speed pair VZ and radial VZ, a rotational speed VP of the turntable 6.

Anyway, when the value of the TETA angular position of the probe 8 reaches 360 degrees, the guide rollers of the turntable 6 stop. The bezel 10A of the right circle of the frame 10 then has a contour of known shape.

In order to feel the second circle of the mount, the probe 8 descends along the axis Z 'under the mount 10. The plate then moves transversely along the transfer axis D in order to reach its second position in which the center of the turntable 6 is positioned between the studs 4 of the two clamps 3 enclosing the left circle of the frame 10.

The feeler 8 is then placed automatically at the height Z inside the second circle of the frame 10 to be measured, against the bezel of this second circle, between the two studs 4 for fixing the lower part of this circle of the frame 10.

The probing of the bezel is then performed in the same manner as before but in the opposite trigonometrical direction.

Claims (13)

1. A method of reading the outline of the bezel (10A) of a rim of an eyeglass frame (10), the method comprising a step of putting a feeler (8) into contact with the bezel (10A) and a step of feeling the bezel (10A) by sliding or rolling said feeler (8) along the bezel (10A), the position (R, TETA, Z) of the feeler (8) being determined and the speed of the feeler (8) comprising first, second, and third components (VP, VR, VZ), the method being characterized in that the first component (VP) of the speed of the feeler (8) is controlled dynamically to vary continuously or in steps during reading as a function of at least one or the other of the second and third components (VR, VZ) of the speed of the feeler (8).
2. An outline reading method according to the preceding claim, wherein the feeler (8) is provided with three degrees of freedom (R, TETA, Z), and the first, second, and third components (VP, VR, VZ) of the speed of the feeler (8) are each associated with a respective one of the three degrees of freedom (R, TETA, Z) of the feeler (8).
3. An outline reading method according to either preceding claim, wherein the feeler (8) turns about an axis of rotation (B) in order to slide along the complete outline of the bezel (10A) of the rim of the eyeglass frame (10), and the first component (VP) of the speed of the feeler (8) is constituted by the speed of rotation (VP) of the feeler (8) about said axis of rotation (B).
4. An outline reading method according to the preceding claim, wherein the second component of the speed of the feeler (8) constitutes a transverse component (VR) of the speed of the feeler (8) of axis perpendicular to the axis of rotation (B) of the feeler (8).
5. An outline reading method according to either one of the two preceding claims, wherein the third component of the speed of the feeler (8) constitutes an axial component (VZ) of the speed of the feeler (8) of axis parallel to the axis of rotation (B) of the feeler (8).
6. An outline reading method according to any preceding claim, wherein the first component (VP) of the speed of the feeler (8) decreases when the second and/or third component (VR, VZ) of the speed of the feeler (8) increases.
7. An outline reading method according to any preceding claim, wherein the second component (VR) and the third component (VZ) of the speed of the feeler (8) both vary continuously, each in a range of speeds subdivided into intervals, the control means (102) modifying the first component (VP) of the speed of the feeler (8) when the second and/or third component (VR, VZ) of the speed of the feeler (8) changes interval.
8. Apparatus for reading the outline (1) of the bezel (10A) of a rim of an eyeglass frame (10), the apparatus having holder means (3, 4) for holding the frame (10), a feeler (8), determination means (101) for determining the position (R, TETA, Z) of the feeler (8), and control means (102) for controlling a first component (VP) of the speed of the feeler (8), the apparatus being characterized in that the determination means (101) are adapted to determine at least one or the other of the second and third components (VR, VZ) of the speed of the feeler (8), and the control means (102) are suitable for controlling the first component (VP) of the speed of the feeler (8) dynamically, continuously or in steps, as a function at least of one or the other of the second and third components (VR, VZ) of the speed of the feeler (8) as determined by the determination means (101).
9. Outline reader apparatus (1) according to the preceding claim, wherein the feeler (8) is provided with three degrees of freedom (TETA, R, Z), a first of the three degrees of freedom (TETA) of the feeler (8) being constituted by its ability to pivot about an axis of rotation (B), a second of the three degrees of freedom (R) of the feeler (8) being constituted by its ability to move relative to the axis of rotation (B), and a third of the three degrees of freedom (Z) of the feeler (8) being constituted by its ability to move in translation along an axis parallel to the axis of rotation (B).
10. Outline reader apparatus (1) according to the preceding claim, wherein the control means (102) are suitable for controlling the first component (VP) of the speed of the feeler (8) in the first of the three degrees of freedom (TETA) of the feeler (8).
11. Outline reader apparatus (1) according to either one of the two preceding claims, wherein the determination means (101) are suitable for determining the second component (VR) of the speed of the feeler (8) in the second of the three degrees of freedom (R) of the feeler (8).
12. Outline reader apparatus (1) according to any one of the three preceding claims, wherein the determination means (101) are suitable for determining the third component (VZ) of the speed of the feeler (8) in the third of the three degrees of freedom (Z) of the feeler (8).
13. Outline reader apparatus (1) according to any one of claims 8 to 12, that comprises a turntable (6) mounted to rotate about the axis of rotation (B) relative to the fastener means (3, 4) for fastening the frame (10), said turntable (6) carrying a reader subassembly (15) that includes the feeler (8) that is movable firstly along a direction parallel to the axis of rotation (B) and secondly in a plane transverse to the axis of rotation (B), the reader subassembly (15) further including another axis of rotation referred to as the carrier axis (A) extending transversely to the surface of the turntable (6) and a carrier arm (18) that has one of its ends mounted to turn about said carrier axis (A) and that has said feeler (8) mounted thereon at its other end.

Images