EP1391264A1 - Vertical apparatus and method for grinding an ophthalmic lens - Google Patents

Vertical apparatus and method for grinding an ophthalmic lens Download PDF

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Publication number
EP1391264A1
EP1391264A1 EP03291696A EP03291696A EP1391264A1 EP 1391264 A1 EP1391264 A1 EP 1391264A1 EP 03291696 A EP03291696 A EP 03291696A EP 03291696 A EP03291696 A EP 03291696A EP 1391264 A1 EP1391264 A1 EP 1391264A1
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EP
European Patent Office
Prior art keywords
lens
axis
grinding
support
grinding wheel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03291696A
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German (de)
French (fr)
Inventor
Jean-Jacques Videcoq
Raynald Longuet
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Briot International SA
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Briot International SA
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Publication date
Application filed by Briot International SA filed Critical Briot International SA
Publication of EP1391264A1 publication Critical patent/EP1391264A1/en
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
    • B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
    • B24B9/08—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass
    • B24B9/14—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass of optical work, e.g. lenses, prisms
    • B24B9/148—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass of optical work, e.g. lenses, prisms electrically, e.g. numerically, controlled
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B27/00—Other grinding machines or devices
    • B24B27/0046—Column grinding machines

Definitions

  • the present invention relates to a device for ophthalmic lens grinding comprising a frame, a grinding wheel rotatably mounted on the frame around a grinding wheel axis, a lens support movable relative to the frame and on which can be rotatably mounted a lens around a lens axis parallel to the grinding wheel axis, means motors adapted to move said support towards the grinding wheel so as to bring the lens into contact with the grinding wheel, and motor means control means.
  • these devices include a cylinder whose movable rod can slide relative to the frame, the free end of the cylinder rod constituting a movable stop which limits the angular movement of the carriage.
  • the shape to be given to the ophthalmic lens is associated with position data of the movable stop as a function of the angular position of the lens around its axis of rotation, during grinding.
  • the position of the movable stopper is linked to the angular position of the lens around its axis.
  • the pressure (or effort) of grinding which represents the force exerted by the grinding wheel on the ophthalmic lens, is generated only by gravity, that is to say by the weight of the mobile assembly formed of all the parts carried by the carriage, therefore mainly by the weight of the carriage.
  • the end of the movable rod of the cylinder which forms the movable stop for the carriage, is equipped with a button to detect the contact between the carriage and the movable stop. So at the end of the process grinding, when the shape to be given to the lens is reached, the key detects a contact at each position angle of the lens around its axis. When such cycle occurs, the carriage is released from the grinding wheel so to remove the finished lens.
  • the main purpose of the invention is to remedy these disadvantages, and in particular to reduce the duration of the phase initial reconciliation, without risk of breakage of roughing.
  • the means of command include means for acquiring data from shape of the outline of the lens blank to be ground, lens contour shape data to be obtained, and position data, with respect to said contours, of the axis of rotation of the lens and calculation means which develop a position reference for the lens support relative to the grinding wheel dependent on said shape data and position.
  • Figure 1 partially shows a device grinding according to the invention, in its normal position of use, i.e. based on a work surface horizontal.
  • the device grinding according to the invention essentially comprises a frame 1, a grinding wheel 2 (Figure 2) rotatably mounted on the frame around a vertical grinding wheel axis ZZ, and a support lens or carriage 3 pivotally mounted relative to the frame 1 around a vertical axis Z'Z '.
  • the frame 1 is essentially formed by a base 5 can rest horizontally on a work surface by via support feet 6 which define a planar bearing surface, and a bracket 7 rigidly fixed to the base 5.
  • the carriage 3 is essentially formed by a bar profile supporting lens shaft 9 rotating around a vertical axis Z '' Z '' located at a distance from the axis Z 'Z'.
  • the lens shaft 9 is consisting of two solidly rotating half-shafts, of which one is secured to a grinding lens or blank 10A, via a grinding adapter 11 ( Figure 2) pasted on it.
  • the carriage 3 is rigidly fixed to a toothed sector 12 extending in a horizontal plane.
  • the lens shaft 9 is, during the operation of grinding, driven in rotation around its axis Z '' Z '' by drive means (not shown) so as to give the lens an angular position ⁇ depending on the time.
  • the carriage 3 is pivotally mounted around the axis Z'Z ' materialized by pins 13, through bearings 15.
  • the stem 7 has a stem head 17 at its upper end, on which the body of a electric motor 19, preferably a current motor continued.
  • the motor output shaft 19 is integral with a drive pinion (not shown) meshing with a wheel tooth 21, which forms a double transmission pinion with a second toothed wheel 22, which is in engagement with the toothed sector 12.
  • the jib head 17 also supports an encoder incremental 23 defining a means of controlling angular displacements of the toothed sector 12, and therefore of the carriage 3, around the axis Z'Z '.
  • Angular displacements of the toothed sector 12 are identified by the angular position ⁇ of the sector around the axis Z'Z '.
  • the grinding device further comprises electronic control means 30 for the motor 19.
  • the toothed sector 12 rigidly supports on its face upper, a flap 32 which constitutes an operating member a switch 33, fixed on the stem head 17 and electrically connected to the motor 19.
  • the grinding operation consists in moving the ophthalmic lens 10 relative to grinding wheel 2 in rotation, so as to obtain the form 10B shown in mixed lines in Figure 2, starting from the shape generally circular of a lens blank 10A, such as shown in phantom in Figure 2 and in solid lines in Figure 1.
  • r f ( ⁇ ) characteristic of the lens shape to be obtained by the grinding operation. The determination of this law is performed by selecting a pre-recorded form, or by acquisition of the shape of a frame or a template lens. This can be done by means known.
  • the control law ⁇ g ( ⁇ ) is stored in the motor 30 control means 19.
  • the control means 30 are provided with means 51 for acquiring data S 1 in the shape of the outline of the lens blank to be ground 10A, data S 2 in the shape of the outline of the lens to be obtained 10B, and data S 3 position of the axis Z '' Z '' of rotation of the lens 10 relative to these contours.
  • acquisition means 51 can for example be storage means connected to a machine for fitting the grinding adapter 11, capable of detecting the geometric characteristics of the blank.
  • the control means 30 also include calculation means 55 which prepare a setpoint S for the position of the support 3 relative to the grinding wheel 2, this setpoint S being calculated as a function of the shape and position data S 1 , S 2 , S 3 from the acquisition means 51.
  • the set point in position of the support 3 relative to the grinding wheel 2 corresponds to the desired spacing between the respective axes of rotation of the grinding wheel ZZ and the lens Z "Z".
  • the means of control 30 include position control means 57 which control the movements of the support 3 as a function of the setpoint signal S and a control signal from encoder 23.
  • the control law is provided so that the speed of movement of the support 3 relative to the grinding wheel 2, before contact of the lens 10 with the grinding wheel, is greater than this speed after contact .
  • the speed is defined by the means of the angular speed d ⁇ / dt taken respectively from the start of the movement of the support until the contact of the lens with the grinding wheel on the one hand, and from the contact until the end of the grinding on the other hand.
  • the position control of the support 3 as a function, among other parameters, of the data S 1 of the shape of the outline of the blank 10A, makes it possible to manage a depth of cut of the tool, as well as a torque exerted on the lens 10, and generated by the cutting force.
  • the depth of cut and the torque resistant can be managed according to objectives previously determined machining, e.g. speed machining, the application of a minimum torque or a torque constant, etc ...
  • the grinding effort can be controlled at any time with high precision, in order to avoid breakage of the lenses during the grinding operation and reduce as much as possible the total duration of the operation.
  • the invention can also be implemented with a different type of motorization, for example a hydraulic or pneumatic actuator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)

Abstract

The lens moulding and shaping mechanism has a body (1) with a mould (2) rotating on the structure around a moving lens support (3). A mechanism acquires digital words and provides a mould contouring (10A). The control mechanism for mould shaping has a mechanism acquiring digital words of mould position with respect to the rotation axis (ZZ).

Description

La présente invention concerne un dispositif de meulage de lentille ophtalmique comportant un bâti, une meule montée rotative sur le bâti autour d'un axe de meule, un support de lentille mobile par rapport au bâti et sur lequel peut être montée rotative une lentille autour d'un axe de lentille parallèle à l'axe de meule, des moyens moteurs adaptés pour déplacer ledit support vers la meule de façon à mettre en contact la lentille avec la meule, et des moyens de commande des moyens moteurs.The present invention relates to a device for ophthalmic lens grinding comprising a frame, a grinding wheel rotatably mounted on the frame around a grinding wheel axis, a lens support movable relative to the frame and on which can be rotatably mounted a lens around a lens axis parallel to the grinding wheel axis, means motors adapted to move said support towards the grinding wheel so as to bring the lens into contact with the grinding wheel, and motor means control means.

On connaít dans l'état de la technique de tels dispositifs, dans lesquels l'axe de meule et l'axe lentille sont horizontaux, le support de lentille étant constitué d'un chariot basculant autour d'un axe également horizontal. Durant l'opération de meulage, l'ébauche de lentille est appliquée contre la meule par basculement du chariot autour de son axe. Généralement, ces dispositifs comprennent un vérin dont la tige mobile peut coulisser par rapport au bâti, l'extrémité libre de la tige de vérin constituant une butée mobile qui limite le débattement angulaire du chariot. La forme à donner à la lentille ophtalmique est associée à des données de position de la butée mobile en fonction de la position angulaire de la lentille autour de son axe de rotation, au cours du meulage.We know in the prior art such devices, in which the grinding wheel axis and the lens axis are horizontal, the lens holder being made up of a carriage tilting around an axis also horizontal. During the grinding operation, the lens blank is applied against the grinding wheel by tilting the carriage around of its axis. Typically, these devices include a cylinder whose movable rod can slide relative to the frame, the free end of the cylinder rod constituting a movable stop which limits the angular movement of the carriage. The shape to be given to the ophthalmic lens is associated with position data of the movable stop as a function of the angular position of the lens around its axis of rotation, during grinding.

Dans les appareils du type précité, la position de la butée mobile est liée à la position angulaire de la lentille autour de son axe. la pression (ou effort) de meulage, qui représente l'effort exercé par la meule sur la lentille ophtalmique, est générée uniquement par gravité, c'est-à-dire par le poids de l'équipage mobile formé de l'ensemble des pièces portées par le chariot, donc essentiellement par le poids du chariot.In devices of the aforementioned type, the position of the movable stopper is linked to the angular position of the lens around its axis. the pressure (or effort) of grinding, which represents the force exerted by the grinding wheel on the ophthalmic lens, is generated only by gravity, that is to say by the weight of the mobile assembly formed of all the parts carried by the carriage, therefore mainly by the weight of the carriage.

Généralement, l'extrémité de la tige mobile du vérin, qui forme la butée mobile pour le chariot, est équipée d'une touche permettant de détecter le contact entre le chariot et la butée mobile. Ainsi, en fin de processus de meulage, lorsque la forme à donner à la lentille est atteinte, la touche détecte un contact à chaque position angulaire de la lentille autour de son axe. Lorsqu'un tel cycle se produit, le chariot est dégagé de la meule de façon à retirer la lentille finie.Generally, the end of the movable rod of the cylinder, which forms the movable stop for the carriage, is equipped with a button to detect the contact between the carriage and the movable stop. So at the end of the process grinding, when the shape to be given to the lens is reached, the key detects a contact at each position angle of the lens around its axis. When such cycle occurs, the carriage is released from the grinding wheel so to remove the finished lens.

De tels dispositifs ne donnent pas entière satisfaction.Such devices do not give whole satisfaction.

En effet, bien que certaines machines prévoient la possibilité de régler le bras de levier du chariot ou de compenser partiellement son poids par des moyens réglables de rappel, l'effort de meulage ne peut être maítrisé pour tous les types de lentilles et durant tout le processus de meulage. On sait qu'un effort de meulage excessif peut entraíner la cassure de la lentille, et qu'un effort de meulage trop faible entraíne un temps d'usinage excessif. Du fait que de nombreuses lentilles ophtalmiques présentent des épaisseurs pouvant varier de façon importante en fonction de la distance à l'axe optique, l'opération de meulage, si l'effort de meulage est maintenu constant durant toute l'opération, peut provoquer des cassures ou conduire à des pertes de temps dues à des profondeurs de passes trop faibles.Indeed, although some machines provide the possibility of adjusting the lever arm of the carriage or partially compensate for its weight by adjustable means as a reminder, the grinding effort cannot be controlled for all types of lenses and during the whole process of grinding. We know that excessive grinding effort can cause the lens to break, and an effort to too low grinding results in excessive machining time. Of many ophthalmic lenses have thicknesses which can vary significantly depending on the distance to the optical axis, the grinding operation, if the grinding force is kept constant throughout the operation, may cause breakage or lead to wasted time due to too deep passes low.

D'autre part, de tels appareils sont complexes du fait de la nécessité d'une double motorisation pour positionner le chariot : l'une pour l'amener dans sa position dans laquelle la lentille est pressée contre la meule, et l'autre pour limiter son débattement, cette dernière motorisation étant en l'occurrence constituée du vérin décrit plus haut.On the other hand, such devices are complex from made the need for a double motorization for position the carriage: one to bring it into its position in which the lens is pressed against the grinding wheel, and the other to limit its travel, this last engine being in this case made up of cylinder described above.

Malgré leur complexité, les machines connues ne permettent pas de différencier l'étape du processus de meulage durant laquelle l'ébauche de lentille est amenée en contact avec la meule, de celle où le meulage est effectivement en cours. Généralement, la phase initiale de mise en contact de l'ébauche avec la meule est effectuée très lentement, en l'absence d'information sur le moment où le contact avec la meule doit avoir lieu. Le diamètre d'une ébauche de lentille pouvant varier très sensiblement, généralement entre 50 mm et 90 mm, la phase initiale de rapprochement peut être rendue, par précaution visant à éviter de casser la lentille, extrêmement longue.Despite their complexity, known machines do not not allow to differentiate the stage of the process from grinding during which the lens blank is brought in contact with the grinding wheel, the one where the grinding is actually going on. Generally, the initial phase of the blank is brought into contact with the grinding wheel very slowly, in the absence of information on when contact with the grinding wheel must take place. The diameter of a lens blank can vary very significantly, generally between 50 mm and 90 mm, the initial phase of reconciliation can be made, as a precaution to avoid breaking the extremely long lens.

L'invention a pour but principal de remédier à ces inconvénients, et notamment de réduire la durée de la phase initiale de rapprochement, sans risque de cassure de l'ébauche.The main purpose of the invention is to remedy these disadvantages, and in particular to reduce the duration of the phase initial reconciliation, without risk of breakage of roughing.

A cet effet, suivant l'invention, les moyens de commande comprennent des moyens d'acquisition des données de forme du contour de l'ébauche de lentille à meuler, des données de forme du contour de lentille à obtenir, et des données de position, par rapport auxdits contours, de l'axe de rotation de la lentille et des moyens de calcul qui élaborent une consigne de position du support de lentille par rapport à la meule dépendante desdites données de forme et de position.To this end, according to the invention, the means of command include means for acquiring data from shape of the outline of the lens blank to be ground, lens contour shape data to be obtained, and position data, with respect to said contours, of the axis of rotation of the lens and calculation means which develop a position reference for the lens support relative to the grinding wheel dependent on said shape data and position.

Suivant d'autres caractéristiques du dispositif conforme à l'invention :

  • les moyens de calcul sont adaptés pour élaborer une consigne de position instantanée du support, telle que la vitesse de déplacement du support par rapport à la meule avant contact de la lentille avec la meule est inférieure à cette vitesse après contact ;
  • les moyens moteurs comprennent un moteur électrique ;
  • le support de lentille est monté pivotant sur le bâti, autour d'un axe de support parallèle à l'axe de lentille, les moyens moteurs étant adaptés pour déplacer angulairement le support autour de l'axe de support ;
  • les moyens moteurs comprennent un moteur électrique fixe par rapport au bâti et le support de lentille est solidaire d'un secteur denté engrenant avec une roue dentée entraínée par l'arbre de sortie du moteur ;
  • le bâti définit une surface plane d'appui sur un plan de travail, et l'axe de support est orthogonal à ladite surface plane d'appui ;
According to other characteristics of the device according to the invention:
  • the calculation means are suitable for developing an instantaneous position reference of the support, such that the speed of movement of the support relative to the grinding wheel before contact of the lens with the grinding wheel is less than this speed after contact;
  • the motor means comprise an electric motor;
  • the lens support is pivotally mounted on the frame, around a support axis parallel to the lens axis, the motor means being adapted to angularly move the support around the support axis;
  • the motor means comprise an electric motor fixed relative to the frame and the lens support is integral with a toothed sector meshing with a toothed wheel driven by the output shaft of the motor;
  • the frame defines a flat support surface on a work plane, and the support axis is orthogonal to said flat support surface;

L'invention vise également un procédé de meulage d'une lentille ophtalmique, dans lequel :

  • on détermine la forme du contour de l'ébauche de lentille à meuler ;
  • on détermine la forme du contour de lentille à obtenir ;
  • on détermine la position, par rapport auxdits contours, de l'axe de rotation de la lentille ;
  • on calcule une consigne de position de l'axe de rotation de la lentille par rapport à la surface de meule en fonction desdites données de forme et de position ; et
  • on commande la position de l'axe de rotation de la lentille par ladite consigne.
The invention also relates to a method of grinding an ophthalmic lens, in which:
  • determining the shape of the outline of the lens blank to be ground;
  • the shape of the lens contour to be obtained is determined;
  • the position, relative to said contours, of the axis of rotation of the lens is determined;
  • a position setpoint of the axis of rotation of the lens relative to the grinding surface is calculated as a function of said shape and position data; and
  • the position of the axis of rotation of the lens is controlled by said instruction.

Suivant d'autres caractéristiques du procédé conforme à l'invention :

  • la consigne de position instantanée de l'axe de rotation de la lentille est telle que la vitesse de déplacement dudit axe par rapport à la surface de meule avant contact de la lentille avec la meule est supérieure à cette vitesse après contact ; et
  • on déplace la lentille dans un plan sensiblement horizontal, la meule étant rotative autour d'un axe sensiblement vertical.
According to other characteristics of the process according to the invention:
  • the instantaneous position setpoint of the axis of rotation of the lens is such that the speed of displacement of said axis relative to the grinding surface before contact of the lens with the grinding wheel is greater than this speed after contact; and
  • the lens is moved in a substantially horizontal plane, the grinding wheel being rotatable about a substantially vertical axis.

Un mode de réalisation de l'invention va maintenant être décrit en référence aux dessins annexés, donnés à titre d'exemple, et sur lesquels :

  • la Figure 1 est une vue partielle en perspective d'un dispositif suivant l'invention, sur laquelle la meule n'est pas représentée;
  • la Figure 2 est une vue en coupe du dispositif de la Figure 1, dans le plan II-II indiqué sur la Figure 1, la meule étant ici représentée et la lentille étant en cours de meulage ; et
  • la Figure 3 est une vue schématique de la meule et de la lentille en cours de meulage.
An embodiment of the invention will now be described with reference to the accompanying drawings, given by way of example, and in which:
  • Figure 1 is a partial perspective view of a device according to the invention, in which the grinding wheel is not shown;
  • Figure 2 is a sectional view of the device of Figure 1, in the plane II-II shown in Figure 1, the grinding wheel being shown here and the lens being grinding; and
  • Figure 3 is a schematic view of the grinding wheel and the lens during grinding.

La Figure 1 représente partiellement un dispositif de meulage suivant l'invention, dans sa position normale d'utilisation, c'est-à-dire en appui sur un plan de travail horizontal.Figure 1 partially shows a device grinding according to the invention, in its normal position of use, i.e. based on a work surface horizontal.

Comme illustré sur les Figures 1 et 2, le dispositif de meulage suivant l'invention comporte essentiellement un bâti 1, une meule 2 (Figure 2) montée rotative sur le bâti autour d'un axe de meule vertical ZZ, et un support de lentille ou chariot 3 monté pivotant par rapport au bâti 1 autour d'un axe vertical Z'Z'.As illustrated in Figures 1 and 2, the device grinding according to the invention essentially comprises a frame 1, a grinding wheel 2 (Figure 2) rotatably mounted on the frame around a vertical grinding wheel axis ZZ, and a support lens or carriage 3 pivotally mounted relative to the frame 1 around a vertical axis Z'Z '.

Le bâti 1 est essentiellement formé d'un socle 5 pouvant reposer horizontalement sur un plan de travail par l'intermédiaire de pieds d'appui 6 qui définissent une surface d'appui plan, et d'une potence 7 fixée rigidement au socle 5.The frame 1 is essentially formed by a base 5 can rest horizontally on a work surface by via support feet 6 which define a planar bearing surface, and a bracket 7 rigidly fixed to the base 5.

Le chariot 3 est essentiellement formé d'une barre profilée supportant l'arbre de lentille 9 à rotation autour d'un axe vertical Z'' Z'' situé à distance de l'axe Z' Z'.The carriage 3 is essentially formed by a bar profile supporting lens shaft 9 rotating around a vertical axis Z '' Z '' located at a distance from the axis Z 'Z'.

De façon classique, l'arbre de lentille 9 est constitué de deux demi-arbres solidairement rotatifs, dont l'un est solidarisé à une lentille à meuler ou ébauche 10A, par l'intermédiaire d'un adaptateur de meulage 11 (Figure 2) collé sur celle-ci. Conventionally, the lens shaft 9 is consisting of two solidly rotating half-shafts, of which one is secured to a grinding lens or blank 10A, via a grinding adapter 11 (Figure 2) pasted on it.

A son extrémité libre supérieure, le chariot 3 est rigidement fixé à un secteur denté 12 s'étendant dans un plan horizontal.At its upper free end, the carriage 3 is rigidly fixed to a toothed sector 12 extending in a horizontal plane.

L'arbre de lentille 9 est, lors de l'opération de meulage, entraíné en rotation autour de son axe Z'' Z'' par des moyens d'entraínement (non représentés) de façon à donner à la lentille une position angulaire  fonction du temps.The lens shaft 9 is, during the operation of grinding, driven in rotation around its axis Z '' Z '' by drive means (not shown) so as to give the lens an angular position  depending on the time.

Le chariot 3 est monté pivotant autour de l'axe Z'Z' matérialisé par des tourillons 13, par l'intermédiaire de paliers 15.The carriage 3 is pivotally mounted around the axis Z'Z ' materialized by pins 13, through bearings 15.

La potence 7 présente une tête de potence 17 à son extrémité supérieure, sur laquelle est fixé le corps d'un moteur électrique 19, de préférence un moteur à courant continu. L'arbre de sortie du moteur 19 est solidaire d'un pignon moteur (non représenté) engrenant avec une roue dentée 21, qui forme un double pignon de transmission avec une deuxième roue dentée 22, laquelle est en prise avec le secteur denté 12.The stem 7 has a stem head 17 at its upper end, on which the body of a electric motor 19, preferably a current motor continued. The motor output shaft 19 is integral with a drive pinion (not shown) meshing with a wheel tooth 21, which forms a double transmission pinion with a second toothed wheel 22, which is in engagement with the toothed sector 12.

La tête de potence 17 supporte également un codeur incrémental 23 définissant un moyen de contrôle des déplacements angulaires du secteur denté 12, et donc du chariot 3, autour de l'axe Z'Z'. Les déplacements angulaires du secteur denté 12 sont repérés par la position angulaire ψ du secteur autour de l'axe Z'Z'.The jib head 17 also supports an encoder incremental 23 defining a means of controlling angular displacements of the toothed sector 12, and therefore of the carriage 3, around the axis Z'Z '. Angular displacements of the toothed sector 12 are identified by the angular position ψ of the sector around the axis Z'Z '.

Le dispositif de meulage comprend en outre des moyens électroniques de commande 30 du moteur 19.The grinding device further comprises electronic control means 30 for the motor 19.

Le secteur denté 12 supporte rigidement sur sa face supérieure, un volet 32 qui constitue un organe de manoeuvre d'un interrupteur 33, fixé sur la tête de potence 17 et relié électriquement au moteur 19.The toothed sector 12 rigidly supports on its face upper, a flap 32 which constitutes an operating member a switch 33, fixed on the stem head 17 and electrically connected to the motor 19.

L'opération de meulage consiste à déplacer la lentille ophtalmique 10 par rapport à la meule 2 en rotation, de façon à obtenir la forme 10B représentée en traits mixtes sur la Figure 2, à partir de la forme généralement circulaire d'une ébauche de lentille 10A, telle que représentée en traits mixtes sur la Figure 2 et en traits pleins sur la Figure 1. Préalablement à l'opération de meulage proprement dite, on détermine la loi r = f() caractéristique de la forme de la lentille à obtenir par l'opération de meulage. La détermination de cette loi est réalisée par sélection d'une forme pré-enregistrée, ou par acquisition de la forme d'une monture ou d'un gabarit de lentille. Cette opération peut être réalisée par des moyens connus.The grinding operation consists in moving the ophthalmic lens 10 relative to grinding wheel 2 in rotation, so as to obtain the form 10B shown in mixed lines in Figure 2, starting from the shape generally circular of a lens blank 10A, such as shown in phantom in Figure 2 and in solid lines in Figure 1. Prior to operation grinding proper, we determine the law r = f () characteristic of the lens shape to be obtained by the grinding operation. The determination of this law is performed by selecting a pre-recorded form, or by acquisition of the shape of a frame or a template lens. This can be done by means known.

La loi de commande ψ = g() qui donne la position angulaire du chariot 3 autour de son axe Z' Z' en fonction de la position angulaire de la lentille autour de son axe de rotation Z''Z'' est déduite de la loi de forme r = f() à donner à la lentille.The control law ψ = g () which gives the position angularity of the carriage 3 around its axis Z 'Z' as a function of the angular position of the lens around its axis of rotation Z''Z '' is deduced from the law of form r = f () to give to the lens.

La loi de commande ψ = g() est mémorisée dans les moyens de commande 30 du moteur 19.The control law ψ = g () is stored in the motor 30 control means 19.

On se réfère à présent plus spécialement à la Figure 1.We now refer more specifically to the Figure 1.

Les moyens de commande 30 sont pourvus de moyens 51 d'acquisition des données S1 de forme du contour de l'ébauche de lentille à meuler 10A, des données S2 de forme du contour de la lentille à obtenir 10B, et des données S3 de position de l'axe Z'' Z'' de rotation de la lentille 10 par rapport à ces contours. Ces moyens d'acquisition 51 peuvent par exemple être des moyens de mémorisation connectés à une machine de pose de l'adaptateur de meulage 11, capable de détecter les caractéristiques géométriques de l'ébauche. Les moyens de commande 30 comprennent également des moyens de calcul 55 qui élaborent une consigne S de position du support 3 par rapport à la meule 2, cette consigne S étant calculée en fonction des données de forme et de position S1, S2, S3 issues des moyens d'acquisition 51. La consigne en position du support 3 par rapport à la meule 2 correspond à l'écartement souhaité entre les axes de rotation respectifs de la meule ZZ et de la lentille Z"Z".The control means 30 are provided with means 51 for acquiring data S 1 in the shape of the outline of the lens blank to be ground 10A, data S 2 in the shape of the outline of the lens to be obtained 10B, and data S 3 position of the axis Z '' Z '' of rotation of the lens 10 relative to these contours. These acquisition means 51 can for example be storage means connected to a machine for fitting the grinding adapter 11, capable of detecting the geometric characteristics of the blank. The control means 30 also include calculation means 55 which prepare a setpoint S for the position of the support 3 relative to the grinding wheel 2, this setpoint S being calculated as a function of the shape and position data S 1 , S 2 , S 3 from the acquisition means 51. The set point in position of the support 3 relative to the grinding wheel 2 corresponds to the desired spacing between the respective axes of rotation of the grinding wheel ZZ and the lens Z "Z".

Dans le mode de réalisation décrit, les moyens de commande 30 comportent des moyens d'asservissement position 57 qui commandent les mouvements du support 3 en fonction du signal de consigne S et d'un signal de contrôle issu du codeur 23.In the embodiment described, the means of control 30 include position control means 57 which control the movements of the support 3 as a function of the setpoint signal S and a control signal from encoder 23.

Afin de réaliser un gain de temps d'usinage, la loi de commande est prévue pour que la vitesse de déplacement du support 3 par rapport à la meule 2, avant contact de la lentille 10 avec la meule, soit supérieure à cette vitesse après contact. La vitesse est définie par les moyennes de la vitesse angulaire dψ / dtprises respectivement depuis le début du mouvement du support jusqu'au contact de la lentille avec la meule d'une part, et depuis le contact jusqu'à la fin du meulage d'autre part.In order to save machining time, the control law is provided so that the speed of movement of the support 3 relative to the grinding wheel 2, before contact of the lens 10 with the grinding wheel, is greater than this speed after contact . The speed is defined by the means of the angular speed d ψ / dt taken respectively from the start of the movement of the support until the contact of the lens with the grinding wheel on the one hand, and from the contact until the end of the grinding on the other hand.

Sur la figure 3, on a illustré le fait que le dispositif décrit précédemment pouvait permettre de décentrer l'axe de rotation Z" Z'' par rapport au centre géométrique O de l'ébauche 10A, de façon par exemple à faire coïncider l'axe de rotation Z'' Z'' avec un centre géométrique de monture ou un centre pupillaire du porteur.In FIG. 3, the fact that the previously described device could allow offset the axis of rotation Z "Z '' from the center geometrical O of the blank 10A, so as for example to make coincide the axis of rotation Z '' Z '' with a center geometric mount or pupil center of the wearer.

La commande de position du support 3 en fonction, parmi d'autres paramètres, des données S1 de forme du contour de l'ébauche 10A, permet de gérer une profondeur de passe de l'outil, ainsi qu'un couple de rotation exercé sur la lentille 10, et généré par l'effort de coupe.The position control of the support 3 as a function, among other parameters, of the data S 1 of the shape of the outline of the blank 10A, makes it possible to manage a depth of cut of the tool, as well as a torque exerted on the lens 10, and generated by the cutting force.

La profondeur de passe et le couple de rotation résistant peuvent être gérés en fonction d'objectifs d'usinage préalablement déterminés, par exemple la rapidité d'usinage, l'application d'un couple minimum ou d'un couple constant, etc... The depth of cut and the torque resistant can be managed according to objectives previously determined machining, e.g. speed machining, the application of a minimum torque or a torque constant, etc ...

Grâce à l'invention qui vient d'être décrite, l'effort de meulage peut être maítrisé à chaque instant avec une grande précision, afin d'éviter la casse des lentilles lors de l'opération de meulage et de réduire autant que possible la durée totale de l'opération.Thanks to the invention which has just been described, the grinding effort can be controlled at any time with high precision, in order to avoid breakage of the lenses during the grinding operation and reduce as much as possible the total duration of the operation.

L'invention peut également être mise en oeuvre avec une motorisation de type différent, par exemple un actionneur hydraulique ou pneumatique.The invention can also be implemented with a different type of motorization, for example a hydraulic or pneumatic actuator.

Claims (9)

Dispositif de meulage de lentille ophtalmique comportant un bâti (1), une meule (2) montée rotative sur le bâti (1) autour d'un axe de meule (ZZ), un support de lentille (3) mobile par rapport au bâti (1) et sur lequel peut être montée rotative une lentille (10) autour d'un axe de lentille (Z'' Z'') parallèle à l'axe de meule (ZZ), des moyens moteurs (19) adaptés pour déplacer ledit support (3) vers la meule (2) de façon à mettre en contact la lentille (10) avec la meule (2), et des moyens (30) de commande des moyens moteurs, comprenant : des moyens (51) d'acquisition des données de forme (S1) du contour (10A) de l'ébauche de lentille à meuler et des données de forme (S2) du contour de la lentille à obtenir (10B), et des moyens de calcul (55) qui élaborent, en fonction du temps, une consigne de position instantanée du support de lentille (3) par rapport à la meule (2), dépendante desdites données (S1, S2) de forme,    caractérisé en ce que lesdits moyens de commande (30) comprennent en outre des moyens (51) d'acquisition des données de position (S3), par rapport auxdits contours, de l'axe (Z"Z") de rotation de la lentille, et en ce que ladite consigne est dépendante desdites données de position (S3).Ophthalmic lens grinding device comprising a frame (1), a grinding wheel (2) rotatably mounted on the frame (1) around a grinding wheel axis (ZZ), a lens support (3) movable relative to the frame ( 1) and on which a lens (10) can be rotatably mounted around a lens axis (Z '' Z '') parallel to the grinding wheel axis (ZZ), motor means (19) adapted to move said lens support (3) towards the grinding wheel (2) so as to bring the lens (10) into contact with the grinding wheel (2), and means (30) for controlling the motor means, comprising: means (51) for acquiring shape data (S 1 ) of the outline (10A) of the lens blank to be ground and shape data (S 2 ) of the outline of the lens to be obtained (10B), and calculation means (55) which develop, as a function of time, an instantaneous position reference of the lens support (3) relative to the grinding wheel (2), dependent on said shape data (S1, S 2 ), characterized in that said control means (30) further comprises means (51) for acquiring position data (S 3 ), relative to said contours, of the axis (Z "Z") of rotation of the lens, and in that said setpoint is dependent on said position data (S 3 ). Dispositif de meulage suivant la revendication 1, caractérisé en ce que les moyens de calcul (55) sont adaptés pour élaborer une consigne de position instantanée du support (3), telle que la vitesse de déplacement du support (3) par rapport à la meule (2) avant contact de la lentille (10) avec la meule est supérieure à cette vitesse après contact.Grinding device according to claim 1, characterized in that the calculation means (55) are adapted to develop an instantaneous position reference of the support (3), such as the speed of movement of the support (3) relative to the grinding wheel (2) before contact of the lens (10) with the grinding wheel is greater than this speed after contact. Dispositif de meulage suivant la revendication 1 ou 2, caractérisé en ce que les moyens moteurs comprennent un moteur électrique (19). Grinding device according to claim 1 or 2, characterized in that the motor means comprise an electric motor (19). Dispositif de meulage suivant l'une quelconque des revendications 1 à 3, caractérisé en ce que le support de lentille (3) est monté pivotant sur le bâti (1), autour d'un axe de support (Z'Z') parallèle à l'axe de lentille (Z'' Z''), les moyens moteurs (19) étant adaptés pour déplacer angulairement le support (3) autour de l'axe de support (Z'Z').Grinding device according to any one of Claims 1 to 3, characterized in that the lens support (3) is pivotally mounted on the frame (1), around a support axis (Z'Z ') parallel to the lens axis (Z '' Z ''), the motor means (19) being adapted to angularly move the support (3) around the support axis (Z'Z '). Dispositif de meulage suivant la revendication 4, caractérisé en ce que les moyens moteurs comprennent un moteur électrique (19) fixe par rapport au bâti (1) et le support de lentille (3) est solidaire d'un secteur denté (11) engrenant avec une roue dentée (22) entraínée par l'arbre de sortie du moteur (19).Grinding device according to claim 4, characterized in that the motor means comprise an electric motor (19) fixed relative to the frame (1) and the lens support (3) is integral with a toothed sector (11) meshing with a toothed wheel (22) driven by the motor output shaft (19). Dispositif de meulage suivant la revendication 4 ou 5, caractérisé en ce que le bâti définit une surface plane d'appui sur un plan de travail, et l'axe de support (Z' Z') est orthogonal à ladite surface plane d'appui.Grinding device according to claim 4 or 5, characterized in that the frame defines a flat support surface on a work surface, and the support axis (Z 'Z') is orthogonal to said flat support surface . Procédé de meulage d'une lentille ophtalmique, à laquelle on associe un axe de rotation (Z"Z") par rapport à une surface de meule, procédé dans lequel : on détermine la forme (S1) du contour (10A) de l'ébauche de lentille à meuler ; on détermine la forme (S2) du contour (10B) de lentille à obtenir ; on détermine la position (S3), par rapport auxdits contours, de l'axe de rotation (Z"Z") de la lentille; on calcule, en fonction du temps, une consigne de position instantanée de l'axe de rotation (Z"Z") de la lentille par rapport à la surface de meule en fonction desdites données (S1, S2, S3) de forme et de position ; et on commande la position de l'axe de rotation (Z" Z") de la lentille par ladite consigne. Method for grinding an ophthalmic lens, to which an axis of rotation (Z "Z") is associated with respect to a grinding surface, method in which: determining the shape (S 1 ) of the contour (10A) of the lens blank to be ground; the shape (S 2 ) of the lens contour (10B) to be obtained is determined; the position (S 3 ), relative to said contours, of the axis of rotation (Z "Z") of the lens is determined; we calculate, as a function of time, an instantaneous position setpoint of the axis of rotation (Z "Z") of the lens with respect to the grinding surface as a function of said data (S 1 , S 2 , S 3 ) shape and position; and the position of the axis of rotation (Z "Z") of the lens is controlled by said instruction. Procédé de meulage suivant la revendication 7, caractérisé en ce que la consigne de position instantanée de l'axe de rotation (Z"Z") de la lentille est telle que la vitesse de déplacement dudit axe (Z" Z") par rapport à la surface de meule avant contact de la lentille (10) avec la meule est supérieure à cette vitesse après contact.Grinding method according to claim 7, characterized in that the instantaneous position setpoint of the axis of rotation (Z "Z") of the lens is such that the speed of movement of said axis (Z "Z") relative to the surface of the grinding wheel before contact of the lens (10) with the grinding wheel is greater than this speed after contact. Procédé de meulage suivant la revendication 7 ou 8 caractérisé en ce qu'on déplace la lentille (10) dans un plan sensiblement horizontal, la meule (2) étant rotative autour d'un axe (ZZ) sensiblement vertical.Grinding method according to Claim 7 or 8, characterized in that the lens (10) is moved in a substantially horizontal plane, the grinding wheel (2) being rotatable around a substantially vertical axis (ZZ).
EP03291696A 2002-08-23 2003-07-08 Vertical apparatus and method for grinding an ophthalmic lens Withdrawn EP1391264A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0210552A FR2843710B1 (en) 2002-08-23 2002-08-23 DEVICE AND METHOD FOR GRASPING OPHTHALMIC LENS
FR0210552 2002-08-23

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1462697A (en) * 1965-12-30 1966-12-16 Lens cutting machine for pairs of glasses
US5347762A (en) * 1992-02-04 1994-09-20 Nidek Co., Ltd. Lens periphery processing apparatus, method for obtaining processing data, and lens periphery processing method
EP0798076A1 (en) * 1996-03-26 1997-10-01 Nidek Co., Ltd Lens grinding apparatus for grinding an eyeglass lens from a plurality of directions
EP0917929A2 (en) * 1997-11-21 1999-05-26 Nidek Co., Ltd. Lens grinding apparatus
EP0960690A1 (en) * 1998-05-29 1999-12-01 Nidek Co., Ltd. Eyeglass lens grinding apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1462697A (en) * 1965-12-30 1966-12-16 Lens cutting machine for pairs of glasses
US5347762A (en) * 1992-02-04 1994-09-20 Nidek Co., Ltd. Lens periphery processing apparatus, method for obtaining processing data, and lens periphery processing method
EP0798076A1 (en) * 1996-03-26 1997-10-01 Nidek Co., Ltd Lens grinding apparatus for grinding an eyeglass lens from a plurality of directions
EP0917929A2 (en) * 1997-11-21 1999-05-26 Nidek Co., Ltd. Lens grinding apparatus
EP0960690A1 (en) * 1998-05-29 1999-12-01 Nidek Co., Ltd. Eyeglass lens grinding apparatus

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FR2843710A1 (en) 2004-02-27

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