EP2210703A1 - Eyeglass lens processing apparatus - Google Patents

Abstract

The device has an electronic or computer unit for controlling position of shaper tools relative to blocking supports. A man/machine interface is connected to the electronic or computer unit and includes a display screen (253) and input unit for inputting numerical values. The electronic or computer unit displays offset fields (301-304) on the display screen and generates a control set point for the shaper tools relative to the blocking supports for shaping an ophthalmic lens so as to form an engagement ridge on an edge face.

Description

The present invention relates generally to the field of eyewear and more specifically to the machining of ophthalmic lenses.

It relates more particularly to a device for trimming an ophthalmic lens for mounting in a bezel of a circle of an eyeglass frame, to form on its field an interlocking rib having a non-uniform transverse profile along the contour of the lens.

TECHNOLOGICAL BACKGROUND

• l'acquisition de la forme du drageoir de chacun des deux cercles de la monture de lunettes choisie par le futur porteur, en particulier de la forme 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 détourage de chaque lentille qui consiste à usiner ou à découper son contour à la forme souhaitée, compte tenu de la forme du drageoir et des paramètres de centrage définis, avec, en fin d'usinage, le biseautage qui consiste à réaliser sur la tranche de la lentille une nervure d'emboîtement destinée à maintenir la lentille dans le drageoir que comporte la monture.

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 three main operations:

• the acquisition of the shape of the bezel of each of the two circles of the eyeglass frame chosen by the future wearer, in particular of the shape of the grooves which run through the inside of each circle 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 trimming of each lens which consists in machining or cutting its contour to the desired shape, taking into account the shape of the bezel and the defined centering parameters, with, at the end of the machining, the beveling which consists in making on the edge lens a nesting rib intended to hold the lens in the bezel that includes the mount.

In the context of the present invention, the main focus is on the third operation of machining the field of the lens.

It is well known to carry out this operation by means of a trimming device which comprises a lens locking medium, a movable trimming tool relative to the medium, and an electronic and / or computer unit for controlling the position of the machining tool relative to the support. This electronic and / or computer unit is then adapted to acquire the coordinates of a plurality of points palpated along the bezel of each circle of the frame, then to derive a control setpoint of the machining tool relative to the support to form on the field of the lens a profiled interlocking rib.

It is also known to use an optimized probing and trimming device, designed to form a non-uniform interlocking rib in the field of the lens, in order to take into account variations in the shape of the bevels of the circles of eyeglass frames.

Such a device allows in particular to take into account the pouring of the bezel, that is to say, variations in the inclination of the bezel along the contour of each circle. This inclination is indeed not negligible in the temporal and nasal areas of the circles, especially when the frame is particularly elongated or curved.

This device also allows to take into account significant variations in the shape of the bezel due to the connection of the bridge, the branch and the nose pad on the frame of the frame.

For this, the device is able to feel a plurality of cross sections of the inner face of each circle and to deduce by calculation an approximation of the three-dimensional shape of the bezel and its front and rear edges.

It is then able to cut the ophthalmic lens so that its interlocking rib has a non-uniform profile which is adapted to the shape of the corresponding profile of the bezel of the circle, in each axial section of the lens. Thus, once the lens nested in the frame, no unsightly gap appears between the frame of the frame and the ophthalmic lens.

Such a probe device is however expensive. Its use is also particularly time consuming. This device also has questionable performance since it does not allow to determine the positions of the nose pads and the branches of the frame, at the risk of leaving problems of mechanical interference between the lens and the frame when the lens is particularly thick.

OBJECT OF THE INVENTION

The object of the present invention is to provide a device for trimming a simple ophthalmic lens and compensating for the defects of the probing devices of eyeglass frame circles.

For this purpose, it is proposed according to the invention a trimming device as defined in claim 1.

The use of a simple probing device, inexpensive, only allows to acquire the shape of the bottom edge of the bezel of each circle of the eyeglass frame selected by the wearer. It is generally not possible to determine with such a device the relative positions of the front and rear edges that border the bezel.

The invention allows the user of the trimming device to measure or approximate by itself the height differences between the leading edges and rear of the bezel in a reduced number of distinct sections of the circle, those that seem relevant, so that the nesting rib is machined based on these differences in heights.

The measurement of the differences in heights then has the advantage of being able to be carried out without particular tools and of being little time-consuming.

The measurements made are then entered on the trimming device so that the latter works the interlocking rib according to a non-uniform profile making it possible, on the one hand, to avoid the problems of mechanical interference between the lens and the frame, and, on the other hand, to prevent the field of the lens from extending away from the circle by revealing an unsightly gap (also called faceting effect).

More specifically, it is generally found that the difference in heights between the front and rear edges of the bezel varies continuously along the circle. This height difference can therefore be easily approximated in each axial section of the circle, from a measurement of height differences into three distinct sections of the circle.

Moreover, the difference in height can be measured either between the front and rear edges of the bezel, or between the front edge of the bezel and an obstacle of the circle (branch, bridge, nose pad), so as to ensure that the lens Once cut off, do not interfere with this obstacle. The user thus has the freedom to optimize the clipping of the ophthalmic lens at his convenience.

Other advantageous and non-limiting features of the clipping device according to the invention are set out in the other claims.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

The description which follows, with reference to the accompanying drawings, given by way of non-limiting example, will make it clear what the invention consists of and how it can be achieved.

• la figure 1 est une vue en perspective d'une monture de lunettes cerclée ;
• la figure 2 est une vue en perspective d'une portion d'un cercle de la monture de lunettes de la figure 1 ;
• la figure 3 est une vue en perspective d'une lentille ophtalmique ;
• la figure 4 est une vue en perspective d'une portion de la lentille ophtalmique de la figure 3 ;
• la figure 5 est une vue en perspective d'un appareil de lecture de contour de cercle de monture de lunettes, dans lequel est installée la monture de lunettes de la figure 1 ;
• la figure 6 est une vue schématique d'un appareil de détourage d'une lentille ophtalmique, dans lequel est bloquée la lentille ophtalmique de la figure 3 ;
• la figure 7A est une vue schématique d'une meulette de finition de l'appareil de détourage de la figure 6 ;
• les figures 7B et 7C sont des vues schématiques de deux variantes de réalisation de la meulette de finition de la figure 7A ;
• les figures 8 et 9 sont des vues de l'écran d'affichage de l'appareil de détourage de la figure 6 ;
• les figures 10 à 15 sont des vues en coupe, en différentes sections transversales, de la lentille ophtalmique de la figure 3 et de la monture de lunettes de la figure 1 emboîtées l'une dans l'autre.

In the accompanying drawings:

• the figure 1 is a perspective view of a rimmed eyeglass frame;
• the figure 2 is a perspective view of a portion of a circle of the eyeglass frame of the figure 1 ;
• the figure 3 is a perspective view of an ophthalmic lens;
• the figure 4 is a perspective view of a portion of the ophthalmic lens of the figure 3 ;
• the figure 5 is a perspective view of an eyeglass frame contour reading device, in which is installed the spectacle frame of the figure 1 ;
• the figure 6 is a schematic view of a device for trimming an ophthalmic lens, in which is blocked the ophthalmic lens of the figure 3 ;
• the Figure 7A is a schematic view of a finishing grind of the trimming device of the figure 6 ;
• the Figures 7B and 7C are schematic views of two alternative embodiments of the finishing wheel of the Figure 7A ;
• the Figures 8 and 9 are views of the display screen of the clipping machine of the figure 6 ;
• the Figures 10 to 15 are sectional views, in different cross-sections, of the ophthalmic lens of the figure 3 and the spectacle frame of the figure 1 nested one inside the other.

Eyeglass frame

On the figure 1 , there is shown a rimmed spectacle frame 10 comprising two circles 11 (or surrounds) each intended to receive an ophthalmic lens and to be positioned facing one of the two eyes of the wearer when the latter carries said frame. The two circles 11 are connected to each other by a bridge or bridge 12. They are each further equipped with a nose pad 13 adapted to rest on the wearer's nose and a branch 14 adapted to rest on one of the wearer's ears. Each branch 14 is articulated on the corresponding circle by means of a barrel 15.

As shown in figure 2 , the two circles 11 of the eyeglass frame 10 have an inner face having an inner groove, commonly called bezel 16. This bezel 16 here has a dihedral cross section, with two front flanks 16A and 16B rear and a ridge 17. It is bordered by two edges before 18 and rear 19. Alternatively, the bezel could of course have a different shape, for example in an arc.

A mean plane P1 and an average axis A1 are defined here with respect to each of the circles 11. The average plane P1 is defined as the plane that passes as close as possible to all the points of the bottom edge 17 of the bezel 16. The coordinates of this plane can for example be obtained by applying the least squares method to the coordinates of a plurality of points of the bottom of the bezel. The average axis A1 is defined as the axis normal to the average plane P1, which passes through the center of gravity of the points of the bottom edge 17 of the bezel 16.

The cross section S _j of each circle 11 is also defined as the intersection of this circle 11 with a plane P2 passing through the mean axis A1 and having an orientation TETA _j about this axis.

Each cross section S _j defines a circle profile P _j . Each of these profiles P _j here comprises two parallel segments corresponding to the traces of the front edges 18 and rear 19 in the P2 plane, and two V-shaped segments corresponding to the traces of the front flanks 16A and rear 16B in this plane P2.

The circle profiles P _j have variable shapes along the contour of each circle 11.

In particular, as shown by the figures 10 and 12 the front and rear flanges 18 respectively have first and second distances to the average axis A1 whose difference, called the offset height D _j , varies along the contour of each circle 11.

The offset height D _j is more precisely defined as the difference between, on the one hand, the minimum distance to the average axis A1 of the trace of the leading edge 18 in the cross section S _j considered, and, on the other hand , the minimum distance to the average axis A1 of the trace of the rear rim 19 in this cross section S _j .

The spectacle frame 10 is also arched. The bezels 16 are thus poured, that is to say twisted. Therefore, as shown in figure 2 each transverse S _j of the bezel 16 has a proper inclination. This inclination, which varies along the bezels 16, is quantified, in each cross section S _j , using an angle called the pouring angle C _j . The angle of discharge C _j corresponds to the angle formed between the bisector F _j bezel 16 and the average plane P1 of the circle 11. This angle of pouring C _j is generally zero in the nasal areas of the circles 11 of the frame 10 and maximum in the temporal zones. We understand, with the help of Figures 10 and 11 that the pouring of the circles 11 has an influence on the offset height D _j .

Considering, as shown in figure 13 , that the nasal plates 13 (and the barrels 15) belong and extend in the extension of the rear flanges 19, it is also understood that these nose pads 13 (and barrels 15) have an influence on the offset height D _j .

Ophthalmic lens

As shown by Figures 3 and 4 , the ophthalmic lens 20 has two optical front 21 and rear 22 faces, and a wafer 23.

This ophthalmic lens 20 has optical characteristics and geometric characteristics.

Among these optical characteristics, in particular, the spherical refractive power of the lens is defined as the magnitude which characterizes and quantifies the "magnifying" effect of the lens on the beam of radiation considered. The point of the lens where the magnifying effect is zero (that is, in the case of a lens having an exclusively spherical optical power, the point where the incident ray and the transmitted ray have the same axis) is called optical center. The corresponding axis is called A2 optical axis.

The edge 23 of the lens has a circular initial contour ( figure 3 ). The lens is however intended to be cut to the shape of the corresponding circle of the spectacle frame 10, so as to be nested in the latter.

As shown in figure 4 it is more specifically intended to be cut to present on its edge 23 a nesting rib 26 (or bevel) lined with two front edges 28 and rear 29 (also called bevel feet). The nesting rib 26 here has a V-shaped section, with a crown edge 27 running along the edge 23 of the lens, and on either side of this vertex edge 27, two flanks before 26A and rear 26B.

Alternatively, the edge of the ophthalmic lens could be cut off so as to have a different shape profile. The lens could for example be cut out to present a machined nesting rib on the side of its only rear flank and bordered on one side by a rear edge ( Figure 7B ). In this example, the leading edge of the nesting rib is then formed by the front face of the lens, and is therefore not machined (or only bevelled). It is then understood that the apex edge of the interlocking rib is constituted by the line joining the front face of the lens and the trailing edge of the interlocking rib. Such a lens is more precisely described in the document FR 2 904 703 .

Furthermore, the axial section S ' _i of the ophthalmic lens 20 is defined as the intersection of this lens with a half-plane P3 which is delimited by the optical axis A2 and which has an orientation TETA' _i about this axis.

Each axial section S ' _i of the ophthalmic lens 20 defines a lens profile P' _i . Each of these profiles P ' _i here comprises two parallel segments corresponding to the traces of the leading edges 28 and rear 29 in the half-plane P3, and two V-shaped segments corresponding to the traces of the front flanks 26A and rear 26B in this half plane P3 .

The axial sections S ' _i of the lens 20 and transverse Si of the frame 10 are said to be "corresponding" when the angular positions TETA ' _i and TETA _j of the planes which define them are equal.

Reading device

For the implementation of the method according to the invention, one can have a shape reading device. This form of reading device is a means well known to those skilled in the art and does not own the subject of the invention described. For example, it is possible to use a shape reading apparatus as described in the patent EP 0 750 172 or marketed by Essilor International under the trademark Kappa or under the trademark Kappa CT.

The figure 5 is a general view of this form reading apparatus 100, as it is presented to its user. This apparatus comprises an upper cover 101 covering the whole of the apparatus with the exception of a central upper portion in which a spectacle frame 10 is arranged.

The shape reading apparatus 100 is intended to raise the shape of the bottom edge of the bezel of each circle 11 of this spectacle frame 10.

The shape reading apparatus 100 shown on the figure 5 comprises a set of two jaws 102, at least one of the jaws 102 is movable relative to the other so that the jaws 102 can be moved towards or away from each other to form a clamping device. Each of the jaws 102 is further provided with two clamps each formed of two pads 103 movable to be adapted to clamp the spectacle frame 10 between them in order to immobilize it.

In the space left visible by the central upper opening of the cover 101, a frame 104 is visible. A plate (not visible) can move in translation on the frame 104 along a transfer axis A3. A turntable 105 is pivotally mounted on this plate. This turntable 105 is therefore capable of taking two positions on the transfer axis A3, of which a first position in which the center of the turntable 105 is disposed between the two pairs of studs 103 fixing the right circle of the spectacle frame 10 , and a second position in which the center of the turntable 105 is disposed between the two pairs of studs 103 fixing the left circle of the spectacle frame 10.

The turntable 105 has an axis of rotation A4 defined as the axis normal to the front face of the turntable 105 and passing through its center. It is adapted to pivot about this axis relative to the plate. The turntable 105 furthermore comprises an oblong aperture 106 in the shape of an arc of a circle through which a probe 110 protrudes. This probe 110 comprises a support rod 111 of axis perpendicular to the plane of the front face of the turntable 105 and, at its free end, a feeler pin 112 of axis perpendicular to the axis of the support rod 111. This feeler finger 112 is intended to follow by sliding or possibly rolling the bottom edge of the bezel of each circle 11 of the spectacle frame 10.

The shape reading apparatus 100 comprises actuating means (not shown) adapted, firstly, to slide the support rod 111 along the lumen 106 in order to modify its radial position with respect to the rotation axis A4 of the turntable 105, a second part, to vary the angular position of the turntable 105 about its axis of rotation A4, and, thirdly, to position the feeler finger 112 of the probe 110 to an altitude more or less important compared to the plane of the front face of the turntable 105.

In summary, the probe 110 is provided with three degrees of freedom, including a first degree of freedom R constituted by the ability of the probe 110 to move radially relative to the axis of rotation A4 thanks to its freedom of movement along of the arc formed by the light 106, a second degree of freedom TETA constituted by the ability of the probe 110 to pivot about the axis of rotation A4 by the rotation of the turntable 105 relative to the plate, and a third degree of freedom Z constituted by the ability of the probe 110 to translate along an axis parallel to the axis of rotation A4 of the turntable 105.

Each point read by the end of the probe finger 112 of the probe 110 is located in a corresponding coordinate system R _j , TETA _j , Z _j .

The shape reading apparatus 100 further comprises an electronic and / or computer device 120 making it possible, on the one hand, to drive the actuating means of the shape reading apparatus 100, and, on the other hand, acquiring and recording the coordinates of the end of the probe finger 112 of the probe 110.

Clipping device

The trimming apparatus according to the invention can be made in the form of any cutting or removal machine capable of modifying the contour of the ophthalmic lens 20 to adapt it to that of the circle 11 of a selected frame. and / or any drilling machine adapted to drill holes in the ophthalmic lens to attach it to a circle-less type spectacle frame.

• une bascule 201 qui est montée librement pivotante autour d'un axe de référence A5, en pratique un axe horizontal, sur un châssis non représenté, et qui supporte la lentille ophtalmique 20 à usiner ;
• au moins une meule 210, qui est calée en rotation sur un axe de meule A6 parallèle à l'axe de référence A5, et qui est elle aussi dûment entraînée en rotation par un moteur non représenté ;
• un module de finition 220 qui est monté à rotation autour de l'axe de meule A6, et qui embarque des moyens de perçage 221 de la lentille ophtalmique 20.

In the example schematized on the figure 6 , the trimming apparatus is constituted, in known manner, by an automatic grinder 200, commonly called digital. This grinder includes in this case:

• a latch 201 which is mounted freely pivotally about a reference axis A5, in practice a horizontal axis, on a frame not shown, and which supports the ophthalmic lens 20 to be machined;
• at least one grinding wheel 210, which is set in rotation on a grinding wheel axis A6 parallel to the reference axis A5, and which is also properly rotated by a motor, not shown;
• a finishing module 220 which is rotatably mounted around the wheel axis A6, and which carries piercing means 221 of the ophthalmic lens 20.

The latch 201 is equipped with a lens holder here formed by two shafts and rotation drive 202, 203 of the ophthalmic lens 20 to be machined.

These two shafts 202, 203 are aligned with each other along a blocking axis A7 parallel to the axis A5. Each of the shafts 202, 203 has a free end which faces the other and is equipped with a locking nose of the ophthalmic lens 20.

A first of the two shafts 202 is fixed in translation along the blocking axis A7. The second of the two shafts 203 is instead movable in translation along the blocking axis A7 to effect the compression in axial compression of the ophthalmic lens 20 between the two locking noses.

As schematically represented on the figure 6 the grinder 200 has only one cylindrical grinding wheel 210.

In practice, it comprises rather a train of several grinding wheels coaxially mounted on the wheel axis A6, each grinding wheel being used for a specific machining operation of the ophthalmic lens 20 to be machined.

For the roughing of the lens, the cylindrical grinding wheel 210 is used.

For the finishing of the lens, using a finishing grinder 212 contiguous to the cylindrical grinding wheel 210.

As represented on the Figure 7B , the finishing wheel 212 comprises in particular a cylindrical working face 213 framed by two conical working faces 214, 215, all three of revolution about the wheel axis A6. A left half of this finishing wheel 212 is shaped to simultaneously machine the rear flank and the rear rim of the ophthalmic lens 20, while the right half of this finishing wheel 212 is shaped to simultaneously machine the front flank and the front rim. of the ophthalmic lens 20. This finishing wheel 212 thus makes it possible to cut the ophthalmic lens 20 in such a way that its front and rear flanges 18 and 19 present respectively first and second distances L1 _i , L2 _i to the blocking axis A7 whose difference is a function, called uneven, not entirely uniform along the field of the lens.

In a variant, it will be possible to use a finishing grinder 216 having a single conical working face ( Figure 7B ) for machining the rear flank of the engagement rib of the lens 20 (the leading edge of the interlocking rib being formed by the front face of the lens).

Still in a variant, provision may be made to use a form grinding wheel 217 rotatably mounted about an axis A61 tilting relative to the locking pin A7 ( Figure 7C ). Such a form of grinding wheel 217 has a profile whose shape is, in negative, identical to the shape of the profile that it is desired to generate on the edge of the lens. It presents in particular a so-called beveling groove, for generating the nesting rib on the edge of the lens 20. The inclination of this form wheel 217 makes it possible to machine the field of the lens so that its front edges and rear are both inclined relative to the locking pin and they thus have different distances to the locking axis A7. It is then possible to modify these distances by adjusting the inclination of the axis A61 of the shape wheel relative to the locking pin A7.

As shown in figure 6 , the set of wheels is carried by a carriage, not shown, mounted to move in translation along the wheel axis A6. The translational movement of the trolley is called "transfer" TRA.

It is understood that it is a matter here of making a relative movement of the grinding wheels with respect to the lens and that it will be possible, in a variant, to provide an axial mobility of the lens, the grinding wheels remaining fixed.

The grinder 200 further comprises a connecting rod 230, one end of which is articulated relative to the frame for pivoting about the reference axis A5, and the other end of which is articulated with respect to a nut 231 for pivoting around an axis A8 parallel to the reference axis A5.

The nut 231 is itself mounted to move in translation along a restitution axis A9 perpendicular to the reference axis A5. As schematized on the figure 6 , the nut 231 is a threaded nut threaded with a threaded rod 232 which, aligned along the restitution axis A9, is rotated by a motor 233.

The link 230 furthermore comprises a contact sensor 234, for example constituted by a Hall effect cell, which interacts with a corresponding element of the flip-flop 201. B1 has been noted as the pivot angle of the connecting rod 230 around the reference axis A5 with respect to the horizontal. This angle B1 is linearly associated with the vertical translation, denoted RES (for "restitution"), of the nut 231 along the restitution axis A9.

The finisher 220 has a pivotal mobility around the wheel axis A6, called ESC retraction mobility. Specifically, the finisher 220 is provided with a toothed wheel (not shown) which meshes with a pinion equipping the shaft of an electric motor integral with the wheel carriage. This mobility allows it to move closer to or away from the ophthalmic lens 20.

The drilling means 221 embedded on the finishing module 220 comprise here a drill provided with a drill 222 adapted to make drilling holes in the ophthalmic lens 20 sandwiched between the two shafts 202, 203. This drill is adapted to rotate around a drilling axis A10, orthogonal to the wheel axis A6. This mobility, called PER drilling mobility, makes it possible to orient the drill 222 with respect to the lens.

When, duly sandwiched between the two shafts 202, 203, the ophthalmic lens 20 to be machined is brought into contact with the grinding wheel 210 or the finishing wheel 212, it is subject to effective material removal until that the rocker 201 abuts against the link 230 following a support which, being at the contact sensor 234, is duly detected by it.

For the machining of the ophthalmic lens 20 according to a given contour, it suffices, therefore, firstly to move accordingly the nut 231 along the restitution axis A9, under the control of the motor 233, to control the restitution movement RES and, secondly, to jointly rotate the support shafts 202, 203 around the locking axis A7. The restitution movement of the rocker 201 and the rotational movement of the shafts 202, 203 are controlled in coordination by a control unit 251, duly programmed for this purpose, so that all the points of the contour of the ophthalmic lens 20 are successively brought back at the right diameter.

• le moteur d'entraînement en translation du deuxième arbre 203 ;
• le moteur d'entraînement en rotation des deux arbres 202, 203 ;
• le moteur d'entraînement en translation du chariot porte-meules suivant la mobilité de transfert TRA ;
• le moteur 233 d'entraînement en translation de la noix 231 suivant la mobilité de restitution RES ;
• le moteur d'entraînement en rotation du module de finition 220 suivant la mobilité d'escamotage ESC ;
• le moteur d'entraînement en rotation de la perceuse 221 suivant la mobilité de perçage PER.

This control unit 251 is of electronic and / or computer type and allows in particular to control:

• the drive motor in translation of the second shaft 203;
• the drive motor in rotation of the two shafts 202, 203;
• the drive motor in translation of the grinding carriage according to the transfer mobility TRA;
• the motor 233 driving in translation of the nut 231 according to the restitution mobility RES;
• the drive motor in rotation of the finishing module 220 following ESC retraction mobility;
• the driving motor in rotation of the drill 221 according to the drilling mobility PER.

The grinder 200 finally comprises a Human Machine Interface 252 which here comprises a display screen 253, a keyboard 254 and a mouse 255 adapted to communicate with the control unit 251. This interface HMI 252 allows the user to enter numerical values on the display screen 253 to drive the grinder 200 accordingly.

As represented on the figure 6 , the control unit is implemented on a desktop computer connected to the grinder 200. Of course, alternatively, the software part of the grinder could be directly implemented on an electronic circuit of the grinder. It could also be implemented on a remote computer, communicating with the grinder via a private or public network, for example using an IP (internet) communication protocol.

We have shown on the figure 8 the image displayed by the display screen 253 when the grinder 200 is started.

As shown in figure 8 , the control unit 251 is adapted to simultaneously display on this display screen 253 a plurality of information, including at least three vertical drop fields 301 - 304 for entering numerical values via the HMI interface 252.

Alternatively, it could also display this information successively, one after the other, on a screen of smaller dimensions.

• une première fenêtre 260 dans laquelle s'affichent deux lignes de contour, dont une première 311 est représentative du contour décrit par l'une des extrémités P'_i1du profil de lentille P'_i le long du champ de la lentille, et dont une seconde 310 est représentative du contour décrit par le sommet du profil de lentille P'_i le long du champ de la lentille ;
• une seconde fenêtre 261 dans laquelle s'affichent un profil de cercle P_j et un profil de lentille P'_i, rapprochés l'un de l'autre ;
• une troisième fenêtre 262 dans laquelle s'affichent quatre champs de dénivelés 301 - 304 et quatre champs dits de largeur 305 - 308 ;
• une quatrième fenêtre 263 dans laquelle s'affichent, d'une part, un champ préalable 309 pour la saisie d'un entier naturel N supérieur ou égal à 3, et, d'autre part, une ligne de contour 310 illustrant le contour d'un cercle d'une monture de lunettes ordinaire ;
• une cinquième fenêtre 264 dans laquelle s'affichent quatre champs supplémentaires 311- 314.

Here, the control unit 251 is adapted to display:

• a first window 260 in which two contour lines are displayed, a first one 311 of which is representative of the contour described by one of the ends P ' _i 1 of the lens profile P' _i along the field of the lens, and one of which second 310 is representative of the contour described by the vertex of the lens profile P ' _i along the field of the lens;
• a second window 261 in which is displayed a circle profile P _j and a lens profile P ' _i , brought closer together;
• a third window 262 in which four vertical drop fields 301 - 304 and four fields 305 - 308 are displayed;
• a fourth window 263 in which, on the one hand, a preliminary field 309 is displayed for the input of a natural integer N greater than or equal to 3, and, on the other hand, a contour line 310 illustrating the contour of a circle of an ordinary spectacle frame;
• a fifth window 264 in which four fields are displayed 311-31.

By representative, it is meant that the contour lines 310, 311 are orthogonal projections, in the same plane, with the same effect of scale, corresponding edges of the edge 23 of the ophthalmic lens 20.

The use of these different windows 260 - 264 will be described in more detail later in this presentation.

The method of preparing the ophthalmic lens 20 for mounting in the corresponding circle 11 of the spectacle frame 10, for example the left circle, is implemented as follows.

Reading process

During a first operation, the user proceeds to read the left circle 11 of the eyeglass frame 10, by means of a reading device such as that shown in FIG. figure 5 .

At first, the spectacle frame 10 is inserted between the studs 103 of the jaws 102 of the reading apparatus 100, so that each of its circles 11 is ready to be palpated along a path starting with the insertion of the probe 110 between the two studs 103 which enclose the lower part of the left circle 11 of the frame, then following the bezel 16 of the circle 11, to cover the entire circumference of this circle 11.

In the initial position, when the feeler finger 112 is disposed between the two studs 103, the electronic and / or computer device 120 defines as zero the angular position TETA _j and the altitude Z _j of the end of the probe pin 112 of the feeler 110.

The actuating means then rotate the turntable 105. During this pivoting, the actuating means impose a constant radial force on the probe 110 in the direction of the bezel 16, so that the probe finger 112 of the probe 110 slides the along the bottom edge 17 of the bezel 16 without going up along the front and rear flanks 16A, 16B of the bezel 16.

During the rotation of the turntable 105, the electronic and / or computer device 120 detects the spatial coordinates R _j , TETA _j , Z _j of a plurality of points of the bottom edge 17 of the bezel 16 (for example 360 angularly separated points). one degree). Each point corresponds substantially to the trace of the bottom edge 17 of the bezel in a cross section S _j .

At the end of the complete revolution of the turntable 105, the actuating means stop the rotation of the latter. The spatial coordinates R _j , TETA _j , Z _j of the 360 probed points are then transmitted by the electronic and / or computer device 120 to the control unit 251 of the scanning device. clipping 200.

Clipping process

The clipping method is here implemented by means of a trimming apparatus such as the grinder 200 shown in FIG. figure 6 .

The method here consists in machining the field 23 of the ophthalmic lens 20 to return it to the shape of the left circle 11 of the eyeglass frame 10, so that once the lens 20 is engaged in its circle 11, its front edges 28 and rear 29 respectively extend at a substantially constant distance from the leading edges 18 and rear 19 of the left circle 11, along the contour of this circle.

Indeed, as has been explained above, the offset height D _j between the front edges 18 and rear 19 of the circle 11 varies along the contour of this circle. It is therefore advisable to cut the ophthalmic lens so that its front and rear rims 29 and 28 are also offset relative to one another by a radial distance D ' _i with respect to the optical axis A2.

As will be explained in more detail below, the radial deviation D ' _i in each axial section S' _i of the lens is deduced from the offset height D _j of the circle 11 in the corresponding cross section S _j . The variations of this radial deviation D ' _i along the field 23 of the ophthalmic lens form a mathematical function which is the altitude difference function.

To implement the lens trimming process, the grinder 200 is first started, so that its control unit 251 controls the display of the five windows 260-264 on the display screen 253.

The ophthalmic lens 20, which still has at this stage the circular contour illustrated on the figure 3 is blocked between the two shafts 202, 203 of the latch 201 of the grinder 200, thanks to the mobility in translation of the second shaft 203. The ophthalmic lens 200 is here more precisely locked so that its optical axis A2 is confused with the locking pin A7.

The user then starts the input, on the HMI interface 252, of the information he has at his disposal and which relates to the eyeglass frame 10, to the ophthalmic lens 20 and to the future wearer of the spectacle frame 10 .

In two of the fields 311, 312 of the fifth window 264, the user more precisely enters the inter-pupillary distance Ep of the future carrier and its pupillary height Hp. The interpupillary distance Ep is defined as the horizontal distance between the pupils of the two eyes of the wearer. The pupillary height Hp is defined as the vertical distance that separates, when the wearer is equipped with the eyeglass frame 10 and that he stands straight, the left pupil of the carrier and the lowest point of the left circle 11 of the spectacle frame 10.

The user also enters, in the other two fields 313, 314 of the fifth window 264, the material M of the lens (0 for glass, 1 for polycarbonate) and the height T between the leading edge 18 of the left circle 11 and the bottom ridge 17 of the bezel 16 of this circle. The gripping of the material M makes it possible to machine the lens at a suitable machining speed. The height T is previously measured by the user on the circle 11 of the eyeglass frame 10, in any cross section S _j . This height T is in fact here assumed to be constant along the contour of the left circle 11. In a variant, it could be provided that this field 313 is already filled by a standard value, so that the user is not forced to measure this height. T.

The user then enters, in the preliminary field 309 of the fourth window 263, a natural integer N greater than or equal to 3. This natural integer N is chosen as a function of the shape of the left circle 11. More precisely, this natural integer N is chosen equal to 3 or 4 if the variations of the offset height D _j along the contour of the left circle 11 are reduced. On the other hand, it is chosen equal to 5 or 6 if the variations of the height of offset D _j along the contour of the left circle 11 are important.

As shown on the figure 8 , this natural number N was chosen equal to 4. On the figure 9 he was chosen equal to 3.

As shown by Figures 8 and 9 once this natural integer N is chosen, the control unit 251 controls the display, on the contour line 310, of a number of points P ₁ - P ₄ equal to the natural integer N chosen. These points illustrate the positions of the cross sections S _j of the circle 11 at which the user will manually measure the shift heights D _j .

These points P ₁ - P ₄ are preferably regularly distributed along the contour line 310 and are positioned so that at least one of them is located in the zone of this line corresponding to a nasal area of a circle. .

When, as shown in figure 8 , the natural integer N has been chosen equal to 4, the four points P ₁ - P ₄ displayed are located at the four cardinal points of the contour line 310.

The control unit 251 also controls the display, in the third window 262, of a number of vertical drop fields 301 - 304 equal to the chosen natural number N. It also controls the display of a number of fields of width 305 - 308 equal to this natural number N.

As shown in figure 8 , vertical drop fields 301 - 304 allow to enter the values of four shift heights D _{j = 0} , D _{j = 90} , D _{j = 180} , D _{j = 270} measured in four cross sections S _{j = 0} , S _{j = 90} , S _{j = 180} , S _{j = 270} of the left circle 11.

The fields of width 305 - 308 make it possible to enter the values of four widths at the opening L _{j = 0} , L _{j = 90} , L _{j = 180} , L _{j = 270} of the bezel 16 measured at the same four transverse sections S _{j = 0} , S _{j = 90} , S _{j = 180} , S _{j = 270} of the left circle 11.

To fill these fields, the user takes hold of the eyeglass frame 10, then estimates visually or using a ruler the shift heights D _j and the widths at the opening L _j of the bezel 16 at the level of four transverse sections S _{j = 0} , S _{j = 90} , S _{j = 180} , S _{j = 270} of the left circle 11 located at the four cardinal points of this circle. It then enters these values in the fields 301 - 308 provided for this purpose using the HMI interface 252.

In a variant, the user could simply measure and fill only the vertical drop fields 301 - 304, in which case the width fields 305-308 would be automatically completed by a predetermined standard value.

The control unit 251 then develops a control setpoint to form the engagement rib 26 on the field 23 of the ophthalmic lens 20, so that in each axial section S ' _i of the lens 20, the front ends and rear P'1 _i , P'2 _i of the lens profile P ' _i respectively have first and second distances L1 _i , L2 _i to the blocking axis A7 ( Figure 7A ) whose difference D ' _i is a function not entirely uniform along the field 23 of the lens 20, which depends on the numerical values entered in each of the vertical drop fields 301 - 304.

For this purpose, the control unit 251 calculates the spatial coordinates R ' _i , TETA' _i , Z ' _i of 360 points of the vertex edge 27 of the engagement rib 26, as well as the calculation of the seconds. distances L2 _i and radial deviations D ' _i in each of the 360 axial sections S' _i considered of the lens 20.

The calculation of the spatial coordinates R ' _i , TETA' _i , Z ' _i of the 360 points of the vertex edge 27 of the interlocking rib 26 is carried out by means of the following formulas:

$${\mathrm{TETAʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{TETA}}_{\mathrm{j}}\mathrm{,}$$

$${\mathrm{Zʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{Z}}_{\mathrm{j}}\mathrm{+}\mathrm{f}\left({\mathrm{TETA}}_{\mathrm{j}}\right)\mathrm{.}$$

For i = j and j ranging from 1 to 360, $${\mathrm{R\text{'}}}_{\mathrm{i}}\mathrm{=}{\mathrm{R}}_{\mathrm{j}}\mathrm{-}\mathrm{DELTA}\mathrm{,}$$

$${\mathrm{TETA\text{'}}}_{\mathrm{i}}\mathrm{=}{\mathrm{TETA}}_{\mathrm{j}}\mathrm{,}$$

$${\mathrm{Z\text{'}}}_{\mathrm{i}}\mathrm{=}{\mathrm{Z}}_{\mathrm{j}}\mathrm{+}\mathrm{f}\left({\mathrm{TETA}}_{\mathrm{j}}\right)\mathrm{.}$$

The DELTA constant is calculated conventionally as a function of the height T (between the leading edge 18 of the left circle 11 and the bottom edge 17 of the bezel 16 of this circle), the width at the opening L _j of the bezel 16, and the corners at the apex of the conical working surfaces of the finishing wheel 212 (as shown by the angle C1 on the figure 10 ). This DELTA constant makes it possible to take into account the fact that, once the lens 20 is engaged in the left circle 11, the vertex edge 27 of the engagement rib 20 does not come into contact with the bottom edge 17 of the 16 but is slightly offset from the latter (see Figures 10 to 15 ).

The function f (TETA _j ) may be chosen to be zero or constant or variable, to take into account a possible difference between the general camber of the lens 20 and the left circle 11 of the frame. The choice of this function makes it possible in particular to modify the axial position of the engagement rib 26 on the edge 23 of the ophthalmic lens 20, such that the interlocking rib 26 extends along the optical face. before 21 of the lens 20 or rather in the middle of its slice 23.

The control unit 251 then calculates the trimming rays of the front rim 28 of the ophthalmic lens, that is to say the calculation of the distances L2 _i in each of the 360 axial sections S ' _i considered of the lens 20 .

• L2_i = R'_i - T - K, K étant une constante positive ou nulle.

These clipping rays L2 _i are derived from the following formula:

• L2 _i = R ' _i - T - K, K being a positive constant or zero.

The leading edge 28 of the edge 23 of the ophthalmic lens 20 is therefore designed to extend at a radial distance from the peak edge 27 of the nesting rib 26 constant and equal to a height T + K greater than or equal to at the height of the interlocking rib 26, for example equal to 0.6 millimeters.

Alternatively, this radial distance could of course be chosen differently. It could in particular be chosen to vary according to the numeric values entered in each of the vertical drop fields 301 - 304.

The control unit 251 finally performs the calculation of the altitude difference function, that is to say here to the calculation of the radial deviations D ' _i at the 360 axial sections S' _i considered of the lens 20.

Four offset heights D _{j = 0} , D _{j = 90} , D _{j = 180} , D _{j = 270} having been entered for four cross sections S _{j = 0} , S _{j = 90} , S _{j = 180} , S _{j = 270} of circle 110, the control unit 251 deduces the radial deviation D ' _i at the four corresponding axial sections S' _{i = 0} , S ' _{i = 90} , S' _{i = 180} , S ' _{= 270} of the lens 20, using the following formula:

For i = j and i = 0, 90, 180 and 270, $${\mathrm{OF}}_{\mathrm{i}}\mathrm{=}{\mathrm{D}}_{\mathrm{j}}+\mathrm{DELTA}2.$$

The constant DELTA2 is a positive value close to 0. It is here chosen equal to 0.5 millimeter.

It makes it possible, in the event of a measurement error, to ensure that the radial deviation D _i between the front 28 and rear 29 edges of the field 23 of the lens 20 is sufficient to avoid any interference problem between the rear rim. 29 of the lens 20 and the rear rim 19 of the circle 11 of the frame (see figure 12 ).

It also allows, when the circle 11 of the frame 10 is poured ( figure 11 ), to ensure that the lens remains mountable in the circle even if the shift heights D _j would not have been measured at the level of the most poured areas of the frame of the frame.

It finally allows, when the lens is thick ( figures 13 and 14 ) to ensure that the rear rim 29 of the field of the lens 20 does not interfere with the corresponding nose plate 13 of the circle 11 of the spectacle frame.

In the case where the ophthalmic lens 20 is identified as being a thin lens ( figure 15 ), the value of this DELTA2 constant can be reduced or canceled.

The control unit 251 then determines the radial deviation D ' _i in each of the other 256 axial sections S' _i of the ophthalmic lens 20, by any interpolation function. The interpolation function is here a continuous Lagrange function whose derivative is continuous and has an absolute value which remains below a predetermined threshold value.

Alternatively, the control unit 251 could be adapted to develop the control setpoint so that the altitude difference function varies in stages between each of the four axial sections S ' _{i = 0} , S' _{i = 90} , S ' _{i = 180} , S ' _{i = 270} considered.

• Pour i allant de 0 à 90, $${\mathrm{Dʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\mathrm{+}\left({\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\mathrm{-}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\right)\mathrm{.}\sin \left({\mathrm{TETAʹ}}_{\mathrm{i}}\right)\mathrm{.}$$
  
• Pour i allant de 90 à 180, $${\mathrm{Dʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\mathrm{+}\left({\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\mathrm{-}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\right)\mathrm{.}\sin \left({\mathrm{TETAʹ}}_{\mathrm{i}}-90\right)\mathrm{.}$$
  
• Pour i allant de 180 à 270, $${\mathrm{Dʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\mathrm{+}\left({\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\mathrm{-}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\right)\mathrm{.}\sin \left({\mathrm{TETAʹ}}_{\mathrm{i}}-180\right)\mathrm{.}$$
  
• Pour i allant de 270 à 360, $${\mathrm{Dʹ}}_{\mathrm{i}}\mathrm{=}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\mathrm{+}\left({\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\mathrm{-}{\mathrm{Dʹ}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\right)\mathrm{.}\sin \left({\mathrm{TETAʹ}}_{\mathrm{i}}-270\right)\mathrm{.}$$
  

In another variant, the interpolation function may be a trigonometric function calculated as follows:

• For i ranging from 0 to 90, $${\mathrm{OF}}_{\mathrm{i}}\mathrm{=}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\mathrm{+}\left({\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\mathrm{-}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\right)\mathrm{.}\sin \left({\mathrm{TETA\text{'}}}_{\mathrm{i}}\right)\mathrm{.}$$
  
• For i ranging from 90 to 180, $${\mathrm{OF}}_{\mathrm{i}}\mathrm{=}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\mathrm{+}\left({\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\mathrm{-}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{90}}\right)\mathrm{.}\sin \left({\mathrm{TETA\text{'}}}_{\mathrm{i}}-90\right)\mathrm{.}$$
  
• For i ranging from 180 to 270, $${\mathrm{OF}}_{\mathrm{i}}\mathrm{=}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\mathrm{+}\left({\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\mathrm{-}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{180}}\right)\mathrm{.}\sin \left({\mathrm{TETA\text{'}}}_{\mathrm{i}}-180\right)\mathrm{.}$$
  
• For i ranging from 270 to 360, $${\mathrm{OF}}_{\mathrm{i}}\mathrm{=}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\mathrm{+}\left({\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{0}}\mathrm{-}{\mathrm{OF}}_{\mathrm{i}\mathrm{=}\mathrm{270}}\right)\mathrm{.}\sin \left({\mathrm{TETA\text{'}}}_{\mathrm{i}}-270\right)\mathrm{.}$$
  

• Pour i allant de 0 à 359, $${\mathrm{L}\mathrm{1}}_{\mathrm{i}}\mathrm{=}{\mathrm{L}\mathrm{2}}_{\mathrm{i}}\mathrm{+}{\mathrm{Dʹ}}_{\mathrm{i}}\mathrm{.}$$
  

Finally, the control unit 251 deduces radial deviations D ' _i from the trimming rays L1 _i of the rear rim 29 of the ophthalmic lens 20, by means of the following formula:

• For i ranging from 0 to 359, $${\mathrm{The}\mathrm{1}}_{\mathrm{i}}\mathrm{=}{\mathrm{The}\mathrm{2}}_{\mathrm{i}}\mathrm{+}{\mathrm{OF}}_{\mathrm{i}}\mathrm{.}$$
  

• du profil de cercle P_j=0 qui est défini par la première section transversale S_j=0 du cercle gauche 11 et qui présente une hauteur de décalage D_j=0 et une largeur à l'ouverture L_j=0, et
• du profil de lentille P'_i=0 qui est défini par la section axiale S_i=0 correspondante de la lentille 20 et dont la forme est déduite des valeurs L1_i=0, L2_i=0 et R'_i=0 précédemment calculées.

The control unit 251 then controls the simultaneous display in the second window 261:

• of the circle profile P _{j = 0} which is defined by the first transverse section S _{j = 0} of the left circle 11 and which has an offset height D _{j = 0} and a width at the opening L _{j = 0} , and
• of the lens profile P ' _{i = 0} which is defined by the corresponding axial section S _{i = 0} of the lens 20 and whose shape is deduced from the values L1 _{i = 0} , L2 _{i = 0} and R' _{i = 0} previously calculated .

The two profiles P _{j = 0} , P ' _{i = 0} are brought closer to each other, so as to illustrate the manner in which the nesting rib 26 fits into the bezel 16 of the left circle 11.

• de la première ligne de contour 310 qui est représentative du contour décrit par l'arête de sommet 27 de la rainure d'emboîtement 26 le long du champ de la lentille ophtalmique 20, et dont les coordonnées sont déduites des coordonnées R'_i, TETA'_i de l'arête de sommet 27,
• de la seconde ligne de contour 311 qui est représentative du contour décrit par l'extrémité arrière P'1_¡ du profil de lentille P'_i le long du champ de la lentille ophtalmique 20, et dont les coordonnées sont déduites des coordonnées L1_i, TETA'_i du rebord arrière 27 de la lentille ophtalmique.

The control unit 251 also controls the display superimposed in the first window 260:

• of the first contour line 310 which is representative of the contour described by the apex edge 27 of the interlocking groove 26 along the field of the ophthalmic lens 20, and whose coordinates are deduced from the coordinates R ' _i , TETA ' _i of the summit ridge 27,
• the second contour line 311 which is representative of the contour described by the rear end P'1 _¡ of the lens profile P ' _i along the field of the ophthalmic lens 20, and whose coordinates are deduced from the coordinates L1 _i , TETA ' _i of the rear rim 27 of the ophthalmic lens.

Only this second contour line 311 has a shape which is deduced from the altitude difference function.

It will be possible to display this second contour line 311 with two different colors, including a first color for the areas where the edge 23 of the lens 20 has a thickness sufficient to present two front and rear edges 28, 29 ( Figures 10 to 14 ), and a second color for the areas where the edge 23 of the lens does not have a thickness sufficient to present a rear edge 29 ( figure 15 ).

The optician can thus modify the values entered in the vertical drop fields 301 - 304, so as to ensure that the rear flange 29 extends over the entire portion 23 of the lens 20. This flange ensures an aesthetic mounting of the lens in the left circle 11, which would not be the case if the lens was only partially provided on its edge with such a rim.

The user then validates the values entered, so that the control unit 251 can proceed with the trimming of the ophthalmic lens 20.

During this validation step, it is possible to store all the data entered in a new record of a database register accessible to the grinder. Such a register comprises a plurality of records each associated with a spectacle frame previously palpated. Each record then includes an identifier of this mount, and the corresponding values, entered in their time on the display screen. Thus, when a new customer (or wearer of glasses) selects an eyeglass frame identical to a spectacle frame that had already been chosen by a previous client, the user can search the register for the values corresponding to this frame of glasses so that you do not have to enter them again on the display.

The trimming is then carried out in two operations of roughing and finishing.

For the roughing of the lens, the cylindrical grinding wheel 210 is used to roughly reduce the rays of the lens as a function of the calculated shape of the apex edge 27. The cylindrical grinding wheel 210 and the latch 201 are more precisely controlled by relative to each other so as to reduce, for each angular position TETA ' _i of the lens around the locking pin A7, the radius of the lens to a length equal to the radius R' _i .

Then, for the finishing of the lens, the finishing wheel 212 is used. The control unit 251 then drives the axial position (along the blocking axis A7) of this finishing wheel 212 to put a first of its faces. conical workpiece 214, 215 facing one of the front and rear edges of the edge 23 of the ophthalmic lens 20. Then, it controls the radial position of the finishing wheel 212 (relative to the locking pin A7 ) to machine one of the front and rear flanks 26A, 26B of the engagement rib 26 and the front or rear flange 28, 29 adjacent to this flank. The operation is repeated to machine the other flanks of the nesting rib 26 and the flange adjacent to this flank.

The machining is carried out so that, in each axial section S ' _i of the lens, the front edge 28 of the wafer 23 of the lens is situated at a radial distance L 2 _i from the locking pin A 7 and that the rear edge 29 of the edge 23 of the lens is located at a radial distance L1 _i of the locking pin A7.

Once cut off, the lens is then extracted from the grinder 200 using the translational mobility of the second shaft 203, and is then fitted into the left circle 11 of the spectacle frame 10.

In case of failure to assemble, the user visually identifies the zone or zones of the edge 23 of the lens 20 which interfere with the circle 11 of the frame, and then modifies the value (s) entered in the vertical drop fields 301 - 304 for machining the rear rim 29 of the lens 20 further in depth.

It then again blocks the ophthalmic lens 20 between the shafts 202, 203 of the grinding wheel 200, and then starts grinding the grinder again to remove these interference zones.

Claims (10)

Device for trimming (200) an ophthalmic lens (20), comprising: an ophthalmic lens locking medium (202, 203) along a blocking axis (A7), an ophthalmic lens trimming tool (210, 212) movable relative to said locking medium (202, 203), an electronic and / or computer unit (251) for controlling the position of said trimming tool (210, 212) relative to said blocking support (202, 203), a human-machine interface (252) connected to said electronic and / or computer unit (251), which comprises a display screen (253) and digital value input means (254, 255), characterized in that said electronic and / or computer unit (251) is adapted to display simultaneously or successively on said display screen (253) at least three fields (301 - 304), called elevations, for entering numerical values via said gripping means (254, 255), then developing a control setpoint of said trimming tool (210, 212) relative to said locking medium (202, 203), for cutting the ophthalmic lens (20) forming on its field (23) a nesting rib (26) which has, in each axial section (S'i) of the ophthalmic lens (20), a profile (P ' _i ) whose front and rear ends respectively have first and second second distances (L1 _i , L2 _i ) to the blocking axis (A7) whose difference is a function, so-called uneven, not entirely uniform along the field of the ophthalmic lens (20), which depends on the numeric values entered in each of the vertical drop fields (301 - 304). Shaping device according to the preceding claim, wherein said electronic and / or computer unit (251) is adapted to display simultaneously on the display screen (253) at least two contour lines (310, 311) superimposed each function of said driving instruction, only a first is dependent on said elevation function. Trimming device according to the preceding claim, wherein the first of the two contour lines (310) is representative of the contour described by one of the ends of the profile (P'i) of the interlocking groove (26) along the field of the ophthalmic lens (20), and the second of the two contour lines (311) is representative of the contour described by the vertex of the profile (P'i) of the groove interlocking (26) along the field of the ophthalmic lens (20). Trimming device according to one of the preceding claims, wherein said electronic and / or computer unit (251) is adapted to display on said display screen (253) exactly four vertical drop fields (301 - 304). Trimming device according to one of claims 1 to 3, wherein said electronic and / or computer unit (251) is adapted to display on said display screen (253) a preliminary field (309) for the input of a natural integer greater than or equal to 3, then displaying on said display screen (253) a number of vertical drop fields (301 - 304) equal to this natural number. Trimming device according to one of the preceding claims, wherein said electronic unit and / or computer (251) is adapted to develop the control set so that the altitude change function varies continuously. Shaping device according to the preceding claim, wherein said electronic and / or computer unit (251) is adapted to develop the control setpoint so that the altitude difference function has a derivative with respect to the angular position of the axial section ( S ' _i ) concerned, which is continuous. Clipping device according to the preceding claim, wherein said electronic and / or computer unit (251) is adapted to develop the control setpoint such that said derivative is, in absolute value, less than a predetermined threshold value in each axial section (S ' _i ) of the ophthalmic lens (2). Trimming device according to one of claims 1 to 5, wherein said electronic unit and / or computer (251) is adapted to develop the control set so that the altitude difference function varies in stages. Clipping device according to one of the preceding claims, wherein said electronic and / or computer unit (251) is adapted to simultaneously display on the display screen (253) a transverse profile (P _j ) of a frame circle. glasses (10) and the profile (P ' _i ) of said interlocking rib (26).

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