EP2214865A2

EP2214865A2 - Device for correcting the edging of an ophthalmic lens and method for edging an ophthalmic lens

Info

Publication number: EP2214865A2
Application number: EP08856411A
Authority: EP
Inventors: Thomas Aenishanslin
Original assignee: Essilor International Compagnie Generale dOptique SA
Current assignee: EssilorLuxottica SA
Priority date: 2007-09-24
Filing date: 2008-09-19
Publication date: 2010-08-11
Anticipated expiration: 2028-09-19
Also published as: WO2009071771A2; WO2009071771A3; EP2214865B9; EP2214865B1; ATE514524T1; FR2921285A1; FR2921285B1

Abstract

The method involves beveling an ophthalmic lens (100) to form a bevel on edge of the lens surrounded by a rear foot of the bevel, and blocking the ophthalmic lens beveled in a rotatably driving and blocking shaft (11) and a blocking nose (12) around a blocking axis (A1). The edge is retrieved from the ophthalmic lens blocked in the shaft and the nose. The edge retrieving process is carried by machining the rear foot, excluding the bevel, on a portion of surface of the foot using a grinding wheel (7) whose work generator is inclined with respect to the axis (A1). An independent claim is also included for a device for retrieving trimming of an ophthalmic lens.

Description

DETOURAGE RECOVERY DEVICE AND METHOD FOR DISRUPTING AN OPHTHALMIC LENS

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

The present invention relates generally to the machining of ophthalmic lenses and more particularly to the recovery of the cutting of beveled ophthalmic lenses to facilitate their interlocking in eyeglass frame circles.

It relates more particularly to a recovery device of the clipping of a beveled ophthalmic lens. It also relates to a method of trimming an ophthalmic lens comprising a step of beveling the lens and a step of taking up the edge of this beveled lens.

TECHNOLOGICAL BACKGROUND

The technical part of the optician's profession is to mount a pair of corrective ophthalmic lenses on a spectacle frame selected by a wearer. This assembly is broken down into three main operations: - the measurement of the shape of the inner contours of the circles of the frame,

the centering of each lens, which consists of positioning and orienting each lens correctly facing each eye of the wearer, then

- The machining of each lens which consists of cutting or contouring its contour to the desired shape, given the measurements made on the frame and defined centering parameters.

In the context of the present invention, we are more particularly interested in the third operation known as machining. This is specifically for the optician to cut the ophthalmic lens so that it can mechanically and aesthetically adapt to the shape of the corresponding circle of the selected frame, while ensuring the best optical function for which it was conceived.

This machining operation includes, in the case of rimmed frames, a beveling step for forming on the edge of the lens a rib commonly called bevel able to fit into a bezel of the rim of the frame, that is, ie in the groove running along the inner face of the circle.

For aesthetic reasons, the bevel is generally made close to the front face of the lens, so that it is bordered on its rear side by the remaining part of the edge of the lens which has a width that is often large and which is commonly called back bevel foot. Also for aesthetic reasons as well as to enhance the protection of the eyes against radiation, the strongly arched frames surrounding the faces of the carriers are becoming increasingly popular. The circles of this type of strongly arched frames are then twisted, especially in their temporal zones, to adapt to the shapes of the lenses.

The interlocking of the lens in the corresponding circle of the frame is achieved by bringing the lens through the front of the frame and inserting it by pressing into the circle to engage the bevel of the lens in the bezel of the circle of the mount. However, unlike the inner face of the frame circles, the rear bevel foot extends along a cylindrical surface. As a result, during this interlocking, mechanical interferences often appear between the frame of the frame and the rear bevel foot of the lens, thus preventing the lens from being inserted into its circle.

Currently, in the presence of such interference, the optician proceeds to a recovery of the entire portion of the ophthalmic lens, reducing its radius, so as to machine in particular the aforementioned conflict zones.

The major disadvantage of such a method is that this recovery step supposes, besides the machining of the rear bevel foot, the machining of the bevel itself. Therefore, the position of the bevel is, following this recovery, more optimal, so that the maintenance of the lens in the frame of the frame is poorly secured. In addition, not to machine more than necessary the lens, the optician is forced to make multiple retouching and nesting tests, so that the time required for this step of recovery is important.

OBJECT OF THE INVENTION In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes a device and a method for reducing the conflict zones without degrading the quality of maintaining the lens in its circle.

More particularly, there is provided according to the invention a method of trimming an ophthalmic lens comprising a step of beveling this ophthalmic lens to form on its edge a bevel bordered by at least one rear foot of bevel, a step of blocking the tapered ophthalmic lens in locking means and rotational drive around a locking pin, and a step of recovery of the wafer of the ophthalmic lens blocked in said locking means and rotating drive. According to the invention, said recovery step comprises machining the rear bevel foot, excluding the bevel itself, on at least part of its surface, by means of a machining tool whose working generator is inclined with respect to said locking axis.

There is also provided a device for recovering the trimming of a beveled ophthalmic lens, comprising a frame, a machining tool rotatably mounted on the frame about an axis of rotation, a lens holder mounted on the frame and provided with means blocking and rotational driving of the ophthalmic lens around a locking pin, and means for mechanically connecting the lens holder and / or the machining tool relative to the frame allowing a variation of the distance between the locking pin and the machining tool. According to the invention, the machining tool has a working generator inclined with respect to said locking pin and the recovery device comprises mobility means to allow axial mobility of the ophthalmic lens relative to the tool of machining along said locking pin and first rigid or elastic axial abutment means for, during machining, oppose the axial displacement of the ophthalmic lens locked in the locking and rotating means in the opposite direction at the point P1 of the locking pin which is closest to the generating work, and / or oppose the movement of the machining tool in the direction of this point P1.

Since the working generator of the machining tool is inclined relative to the locking axis of the lens, the bevel foot resulting from the clipping recovery extends in a quasi-conical surface of shape close to that the inner face of the corresponding circle of the mount. As a result, this recovery makes it possible to plane the zones of conflict which prevented the insertion of the lens in its circle. In addition, the axial mobility of the lens and the first abutment means can mechanically maintain the only rear foot of the ophthalmic lens facing the machining tool. In this way, only the rear bevel foot is machined by the tool. The bevel is left intact, so that the quality of the maintenance of the lens in the frame remains unchanged. According to a first advantageous characteristic of the routing method according to the invention, during the recovery step, the locking and rotational drive means and / or the machining tool along the axis are axially reclosed. blocking, so that a trailing edge of the bevel of the ophthalmic lens bears against second abutment means associated with the machining tool.

Here, the first abutment means are elastic and form means return of the lens in contact with the tool. The axial mobility of the lens and the return of the locking means and rotational drive of the lens then allow to mechanically maintain a stop connected to the machining tool in contact with the rear flank of the bevel. The machining tool is then guided mechanically by the bevel to machine the only rear foot of bevel.

As a variant, during the recovery step, the locking and rotational driving means are brought axially back along the blocking axis, such that the periphery of the front face of the ophthalmic lens or a front flank the bevel of the ophthalmic lens comes to bear against first rigid stop means.

The first rigid abutment means being fixed relative to the machining tool, they allow to guide the edge of the lens when the latter rotates, so that the only rear foot of bevel remains facing the work surface of the machining tool. Advantageously, during the recovery step, the inclination of the working generatrix with respect to the locking axis remains constant and between 5 and 40 degrees, preferably equal to 12 degrees, or varies to reach a maximum value. within this range of values. In addition, said recovery step comprises machining the entire surface of the rear bevel foot.

Thus, the recovery of the edge of the lens is performed uniformly and aesthetically.

According to another advantageous characteristic of the invention, during said beveling step, the bevel is machined at the edge of the front face of the ophthalmic lens, so that the edge of this ophthalmic lens is devoid of front bevel foot.

Alternatively, said beveling step comprises, besides the machining of the rear bevel foot, the machining of a front bevel foot.

Finally, the method is advantageously applied to ophthalmic lenses having significant camber and / or thickness.

Furthermore, other advantageous and non-limiting features of the clipping recovery device according to the invention are the following:

said first axial abutment means are elastic and recall, during machining, the ophthalmic lens locked in the means for locking and rotating in the direction of said point P1 and / or recall the machining tool in the direction opposed to said point P1; _

said first axial abutment means are arranged to exert a force on the front face of the ophthalmic lens, along an axis substantially parallel to the locking pin, so as to maintain a rear edge of the bevel of said ophthalmic lens in contact with second stop means associated with the machining tool;

said second abutment means are formed by a flank or an edge of the machining tool;

said second abutment means are non-abrasive and / or rotatable with respect to the machining tool about the axis of rotation; said first axial abutment means are rigid and are axially adjustable;

- there is provided elastic return means of the ophthalmic lens against the first axial abutment means;

said first axial abutment means comprise a wheel adapted to bear on the ophthalmic lens for rolling on the periphery of the optical front face of this ophthalmic lens;

- The machining tool comprises a cylindrical grinding wheel of revolution about said axis of rotation and wherein the axis of rotation is inclined relative to said locking axis; - The machining tool comprises a conical grinding wheel of revolution about said axis of rotation and wherein the axis of rotation is substantially parallel to said locking axis;

- The angle of inclination of the generator of work with respect to said locking axis is between 5 and 40 degrees, preferably equal to 12 degrees; a transverse stop of adjustable depth of depth is provided, which is adapted to cooperate by transverse contact with the bevel of the ophthalmic lens locked in said locking and rotational driving means, in order to limit the capacity of the machining depth of the machining tool.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT The following description, with reference to the appended drawings, given by way of non-limiting example, will make it clear what the invention consists of and how it can be achieved.

In the accompanying drawings:

FIGS. 1 and 2 are perspective views, from two different angles, of a device for recovering ophthalmic lens trimming according to the invention; - Figures 3 and 4 are partial sectional views of two embodiments of a machining tool of the recovery device of Figure 1, and an ophthalmic lens being machined locked on a lens holder ;

- Figures 5 and 6 are sectional views of the edge of two ophthalmic lenses fitted into bezels eyeglass frames and two variants of implementation of a clipping method according to the invention. Recovery device

Figures 1 and 2 schematically shows a recovery device 1 of the ophthalmic lens trimming 100, as it is presented to its user.

This recovery device 1 is intended to machine a portion of the edge of an ophthalmic lens 100 previously bevelled, so that this lens is mountable in one of the circles of the eyeglass frame chosen by the future carrier of this lens. The term "beveled lens" is understood to mean a lens whose contour has been cut in order, on the one hand, to have a shape identical to the contour of the corresponding circle of the frame, and, on the other hand, to have a bevel along its edge. By bevel, one hears of course the conventional interlocking ribs of triangular sections such as those shown in Figures 5 and 6, but also those conceivable sections of different shapes, for example rectangular or rounded. Here, the bevel 101 has a leading edge 106 turned on the side of the optical front face 104 of the ophthalmic lens 100 and a rear flank 103 turned on the opposite side. This bevel 101 is further bordered, at least on the side of its rear flank 103, a rear foot 102 bevel initially cylindrical.

The bevel 101 of the ophthalmic lens 100 is anyway shaped to fit into a bezel 111 of the frame 110 of the frame, that is to say in a groove running along the inner face of the circle 110. As shown in Figures 5 and 6, this groove has a triangular section. Alternatively, it may also have a section of different shape, for example rectangular or rounded. The inner face of the circle 110 further comprises, on either side of the bezel 111, a front rim 113 and a trailing edge 112.

The recovery device 1 is more particularly intended for machining the rear bevel foot 102 of the ophthalmic lens 100 in order to avoid, during the engagement of the ophthalmic lens 100 in its circle 110, any contact between the rear bevel foot 102 and the trailing edge 112 of the inner face of the circle 110.

As shown in FIGS. 1 and 2, this recovery device 1 mainly comprises a frame 2 on which a machining tool 7 and a lens holder 10 are mounted.

The lens holder 10 is connected to the frame by mechanical connection means allowing a variation of the spacing between the lens holder 10 and the machining tool 7.

In the illustrated example, the lens holder comprises a base which forms a rocker freely pivotally mounted on the frame 2 about a horizontal axis A5, called the rocker axis. For this purpose, the rocker 14 has a through bore which is engaged on a shaft 3 secured to the frame.

The flip-flop 14 is also freely mounted in translation on the shaft 3 along the flip-flop axis A5 between two abutment positions, including a right abutment position and a left abutment position.

The lens holder 10 further comprises biasing means of the latch 14 in the right stop position, constituted by a compression spring 4 engaged on the shaft 3, in compression between the latch 14 and a portion of the frame 2. The lens holder 10 is equipped with transverse return means for reminding during machining the lens holder 10 to the machining tool 7 and thus maintain the edge of the lens in contact with the working surface of the tool machining 7. These return means are here gravitational, that is to say that they result from the sole weight of the latch 14. For this purpose, the center of gravity of the latch 14 is located at a distance from the the rocker axis A5 and the rocker 14 is weighted so that its weight allows it to naturally rotate around the rocker axis A5, towards the machining tool 7. Alternatively, these transverse biasing means can be elastic (torsion spring type), electro-mechanical, or electrically o-magnetic. The lens holder 10 is finally equipped with locking means and rotational drive of the ophthalmic lens 100. These means comprise two shafts 11 for blocking the lens, aligned with each other along an axis A1 called axis blocking, which is parallel to and distinct from the flip-flop axis A5. In the remainder of the description, the terms axial and transverse will be used with reference to the position of this locking pin A1.

The two shafts 11 are mounted on the rocker 14 to turn around the locking pin A1 and are rotated synchronously by a motor (not shown) via a common drive mechanism (not shown) embedded in the latch 14. Alternatively, it can be provided to drive the two shafts by two separate motors synchronized mechanically or electronically. It will also be possible to provide manual drive means for the two shafts in rotation.

Each of the shafts 11 has a free end which faces the free end of the other shaft and which is equipped with a locking nose 12 of the ophthalmic lens 100. The two locking noses 12 are generally of revolution around each other. the locking pin A1 and each have a generally transverse application face arranged to bear against the corresponding optical face of the ophthalmic lens 100.

The two shafts 11 are movable in translation along the blocking axis A1 to effect the compression in axial compression of the ophthalmic lens 100 between the two locking noses 12. These translations are here manually controlled by means of rollers 13 arranged with either side of the rocker 14, in the axis of the shafts 11, to be accessible to the user. These knobs are here linked to worms screwed into threaded bores of the shafts 11, so that the pivoting of the knobs 13 brings the two shafts 11 closer to one another to rigidly block the ophthalmic lens 100. of course, these axial translations of the shafts 11 may be controlled otherwise, for example by ad hoc drive motors housed in the latch. In another variant, it may be provided that only one of these two trees is movable in translation. The machining tool is in this case constituted by a grinding wheel 7 rotatably mounted about an axis of rotation A3. Alternatively, the machining tool may be constituted by a cutter or a knife rotatably mounted about the axis of rotation A3.

A work generator A6 (FIG. 3) is defined on this machining tool as the axis which is coplanar with the axis of rotation A3, which belongs to or is tangent to the working surface of the tool. machining and which is closest to the shafts 11 blocking the ophthalmic lens 100. In other words, when the edge of the lens is in contact with the machining tool, this generator work corresponds to the line of contact between the machining tool and the lens. Of course, if the tool is a cutter or a knife, this contact is not continuous but rather periodic. The grinding wheel 7 is here cylindrical of revolution and is rotated about the axis of rotation A3 by an electric motor 8 whose body is fixed to the frame 2 and whose output shaft directly carries the grinding wheel. The motor 8 is mounted on the frame so that the axis of rotation A3 is inclined at an angle ALPHA with respect to the locking pin A1. As a result, the work generator A6 of the grinding wheel 7 is inclined at the same angle with respect to the locking pin A1. Due to this inclination, the grinding wheel 7 is adapted to machine the edge of the ophthalmic lens 100 by "breaking" its rear edge and conferring on its rear foot 102 bevel a quasi-conical shape, that is to say a shape approximated to that of a cone.

The angle of inclination ALPHA of this work generator A6 with respect to the blocking axis A1 is preferably between 5 and 40 degrees. It is here equal to 12 degrees.

Alternatively, it may be provided that the axis of rotation of the grinding wheel is parallel to the locking axis of the lens and that the grinding wheel is conical of revolution about its axis of rotation, so that its work generator is inclined relative to the locking pin A1. According to another variant, it may be provided that the axis of rotation of the grinding wheel is inclined relative to the locking axis of the lens and that the grinding wheel is conical of revolution about its axis of rotation, so that its generator working angle is inclined relative to the blocking axis A1. As a further variant, the machining tool may comprise a set of grinding wheels, with in particular a beveling grinding wheel, in such a way that the recovery device is able to cut out and take back the ophthalmic lenses of initially circular contours (semi-circular lenses). finite). Anyway, it is provided means for moistening the grinding wheel which are constituted by a sponge 6 fixed to the frame 2 and located under the grinding wheel 7, in contact with its working surface.

The recovery device 1 furthermore comprises first rigid or elastic axial abutment means 30 for, during machining, opposing the displacement of the ophthalmic lens 100 in the direction opposite to the point P1 which is defined as the point the blocking pin A1 which is closest to the work generator A6 (Figure 3).

According to a first embodiment of the invention, represented in FIGS. 1 and 2, the first axial stop means 30 are rigid and are shaped to form a mechanical stop axially adjustable relative to the grinding wheel 7, along the axis of blocking A1. This mechanical stop is more precisely arranged so that the periphery of the front face 104 of the ophthalmic lens 100 can bear against it.

In the present case, the lens being naturally returned to its right abutment position by the compression spring 4, it is provided that the lens is constantly resting against these first axial abutment means 30.

The first axial abutment means 30 are here mounted on a plate 20 provided with a single pivotal mobility relative to the frame 2 about an axis A2, called the pivot axis, parallel to the flip-flop axis A5. For this purpose, the plate 20 comprises a rectangular plate 21, one of whose edges is provided with a sleeve traversed by a shaft 5 which is fixed on the frame 2, below the shaft 3 and parallel thereto . The sleeve 22 is locked in translation on this shaft 5, for example by means of circlips. In this way, the plate 20 can pivot about the pivot axis A2 to rise in the direction of the lens holder 10 or to lower towards the grinding wheel 7. The plate 21 is perforated to allow, in the lowered position, the passage of the grinding wheel 7 through said plate, so that it can perform its machining function.

The first axial abutment means 30 comprise an arm 31, formed here by a metal rod. This arm 31 is provided at mid-length with a bore engaged on a pin of the plate 20, so that it is rotatable relative to this plate 20 about an abutment axis A4 normal to the plane of the plate 20.

This arm is further extended by a forearm 32 provided at its free end with a nylon wheel 33 adapted to roll on the front optical side of the lens, without scratching it, when the lens pivots about the axis blocking A1.

The forearm 32 is rotatably mounted on the arm 31 about an axis parallel to the abutment axis A4. A vernier adjustment 34 is arranged on the forearm 32 so that its pivoting allows fine adjustment of the orientation of the forearm 32 relative to the arm 31. A screw can block the rotation of the front -arm relative to the arm.

The first axial abutment means 30 further comprise a lever 25 rotatably mounted on the plate 20 about an axis parallel to the abutment axis A4. This lever 25 is provided with a cam adapted to abut against the end of the arm 31 opposite to the forearm 32. This lever is provided to have two stable positions, including an engaged position in which the cam is in position. transverse support against the arm and a disengaged position in which the cam is set back from the arm.

In summary, thanks to the vernier 34 and the lever 25, the first axial stop means 30 are axially adjustable to change the position of the wheel 33 relative to the grinding wheel 7, by changing the angular position of the arm 31 relative to the platen 20 (around the locking pin A4) and the forearm 32 relative to the arm 31. More specifically, the combination of the vernier 34 and the lever 25 allows the user to fine tune the position of the roulette 33 and hence the axial position of the edge of the lens relative to the grinding wheel.

According to a second embodiment of the invention, not shown in the figures but which will be described with reference to FIGS. 1 to 3, the first axial abutment means 30 may be elastic, in order to recall the lens during machining. Ophthalmic 100 blocked in the locking means and rotational drive 11, 12 in the direction of point P1.

In the present case, these first elastic axial abutment means 30 are arranged to exert a return force on the front optical face 104 of the ophthalmic lens 100, along an axis substantially parallel to the blocking axis A1, so as to maintain the trailing edge 103 of the bevel 101 of the ophthalmic lens 100 in contact with second abutment means 51 associated with the machining tool 7. These first axial abutment means 30 are able to exert a return force on the lens of FIG. intensity less than the intensity of the force exerted by the transverse biasing means of the latch 14 on the lens. Therefore, when the lens is rotated about the locking pin A1 and is brought into contact with the grinding wheel by the transverse return means, the contact of the rear flank 103 of the bevel 101 against the second stop means 51 allows axially guiding the lens relative to the machining tool, so that the working surface of the grinding wheel 7 remains in contact with the rear bevel foot 102.

In the example illustrated in FIG. 3, the second abutment means are formed by a flank 51 of the machining tool 7. Thus, the first elastic axial abutment means 30 make it possible to press the rear flank 103 of the bevel 101 of the lens 100 directly against the sidewall 51 of the grinding wheel 7. Optionally, it can be provided that the relevant flank 51 of the grinding wheel 7 is not abrasive to ensure that the grinding wheel slides without effort of removal of material against the rear flank 103 of the bevel 101. In a variant, said second abutment means may be formed by an additional member distinct from the grinding wheel. For example, as shown in 4, this additional member 50 may be constituted by a rigid disk mounted free to rotate on the shaft of the grinding wheel 7, at a distance from the latter. Thus the rigid disk does not turn against the ophthalmic lens 100, so that it preserves the geometric integrity of the bevel 101. As a variant, this additional member may be directly attached to the frame 2, in a fixed position relative to the grinding wheel 7.

Whatever the embodiment of the first axial abutment means 30, the recovery device 1 comprises a cross depth stop 26 which is adjustable in height relative to the grinding wheel 7, to limit the capacity of machining depth of this millstone.

This stop depth 26 pass is reported on the plate 20, above a circular opening (not visible in the figures) which is formed in the plate and by which the grinding wheel 7 protrudes. The stop is here constituted by a cover 26 having a flat peripheral portion 27 which is fixed by screw to the plate 20, and a curved central portion 28 which extends above said circular opening. This curved central portion 28 is opened by a rectangular window 29 designed so that only a radial end portion of the grinding wheel 7 protrudes above the plate 20. Thus, when the lens holder 10 is brought back to the grinding wheel by its transverse return means, the grinding wheel mills the rear bevel foot 102 to a height D1 (FIG. 5) predefined, then the apex of the bevel 101 of the ophthalmic lens 100 comes into contact with the convex central portion 28 of the cover 26, which limits the approximation of the locking pin A1 to the grinding wheel 7.

This depth stop 26 is adjustable in height by changing the angular position of the plate 20 about the pivot axis A2. For this purpose, the frame 2 comprises an adjustment knob 9 graduated angularly which is accessible to the user and whose adjustment of the angular position allows to change the height relative to the frame 2. This adjustment wheel 9 is located under the platen 20, in contact with the end edge of the plate 20 opposite the pivot axis A2. Correspondingly, the plate 20 is pierced with a threaded bore hosting a screw 24 whose operating head is accessible to the user and whose free end is supported against the upper face of the adjustment wheel 9. The association of this screw 24 and this adjustment wheel 9 then allows the user to fine tune the position of the plate 20 about the pivot axis A2 and hence the depth of recovery.

Finally, the recovery device 1 comprises control means 40 of the motors for actuating the grinding wheel 7 and the shafts 11 for locking the ophthalmic lens 100. These control means here comprise two switches 41, 42 which make it possible to start or stop each motor. Method The method according to the invention consists of cutting off the ophthalmic lens

100 so that its bevel 101 is easily nestable in the bezel 111 of the circle 110 of the eyeglass frame selected by the wearer. This method comprises three successive main steps, including a first step of bevelling of the ophthalmic lens 100, a second step of blocking this lens on the lens holder 10 of the recovery device 1, and a third step of recovery of the back foot of bevel 102 of this lens by the grinding wheel 7 of the recovery device 1.

For the implementation of the first so-called beveling step, it will be possible to use a beveling apparatus which is not the subject of the present invention. Such a beveling device, well known to those skilled in the art, is for example described in US 6,327,790 or marketed by the applicant under the trademark Kappa. It generally comprises shafts for holding and rotating the ophthalmic lens to bevel around a first axis, and a beveling wheel which is provided with a bevelling groove and which is rotatably mounted around a second axis substantially parallel to the first axis.

In summary, during this step, the lens is locked on the holding shafts and then is cut off by the beveling wheel by varying, for each angular position of the lens around the first axis, the spacing between the first axis and the second axis.

The axial position of the lens relative to the beveling groove is also controlled. For aesthetic reasons, this axial control is carried out so that the bevel 101 extends close to the optical front face 104 of the ophthalmic lens 100. More specifically, with reference to FIG. 5, the bevel 101 is machined at the edge. of the optical front face 104 of the lens, so that at the end of this step of beveling, the edge of the lens is devoid of foot before bevel and has a rear foot 102 bevel cylindrical width important. As a variant, with reference to FIG. 6, the bevel 101 may be machined at a distance from the edge of the optical front face 104 of the lens, so that at the end of this beveling step, the edge of the lens comprises, besides a cylindrical bevel rear foot 102 of large width, a cylindrical bevel fore foot 105 of smaller width.

Anyway, the lens is then extracted from the clipping apparatus to be nested in the circle 110 of the eyeglass frame. During this interlocking, if a problem due to interference between the rear bevel foot 102 of the ophthalmic lens 100 and the trailing edge 112 of the inner face of the circle 110 is detected, the second step of the blocking of the Ophthalmic lens 100 on the lens holder 10. Such a problem is generally detected on lenses that have strong camber and / or slices of significant thickness. More precisely, the term "high-arched lens" means a lens whose radius of curvature of the front optical face is less than 120 millimeters. In addition, significant thickness is understood to mean a lens whose maximum thickness of the wafer is greater than 7 millimeters.

Alternatively, the detection of such a problem can be performed directly after the beveling of the lens, without attempting to nest the lens in the frame. For example, it will be possible to acquire the thickness of the slice of the lens and / or its camber, and then compare these acquired values with predetermined threshold values beyond which the risk that a nesting problem appears is great.

Anyway, when such a problem is detected, the user raises the rocker 14 by rotating it around the rocker axis A5, then it proceeds to lock the lens between the two shafts 11 of the door The shafts 11, movable in translation along the blocking axis A1, are actuated by means of the knurls 13 to firmly grip the ophthalmic lens 100 between the application faces of the locking noses 12. It will be noted here that the position of the lens relative to the blocking pin A1 does not matter. In particular, it is not necessary to center the lens on this axis. On the other hand, it is important to check that the locking noses 12 do not protrude from the lens.

Once this blocking of the lens has been performed, the user actuates the lever 25 so as to move the wheel 33 away from the grinding wheel 7. Then he descends the rocker 14 by positioning the rear flank 103 of the bevel 101 and the rear bevel foot 102 of the ophthalmic lens 100 against the grinding wheel 7. Finally, it returns the lever 25 to the initial position so that the first axial stop means 30 maintain the lens near the grinding wheel. Using the vernier 34, the user adjusts the position of the lens relative to the grinding wheel 7, positioning the rear of the bevel flush with the right flank of the grinding wheel 7. In other words, it turn the vernier so that only the rear bevel foot of the lens is facing the work surface of the grinding wheel 7.

At this stage, the rear flank 103 of the bevel 101 of the ophthalmic lens 100 is held in abutment against the edge of the grinding wheel 7 by the first axial stop means 30 while the rear bevel foot 102 of the ophthalmic lens 100 is maintained. resting against the work generator A6 of the machining tool 7 by the transverse return means (that is to say in this case by the weight of the rocker 14).

Before resuming the lens, the user adjusts the depth of the grinding wheel 7 by turning the adjustment wheel 9, so as to set the depth stop 26 to the desired height. It will be noted here that the screw 24 will be used only occasionally, in order to calibrate the recovery device 1 so that the graduations marked on the adjustment wheel 9 correspond to the actual pass depths, in millimeters. For this, the "zero" of the adjustment wheel 9 will be adjusted by positioning, with the aid of the screw 24, the opening 29 of the depth-of-depth stop 26 at the outcrop of the working surface of the grinding wheel 7.

During the third so-called resumption step, the user starts the motor 8 for actuating the grinding wheel 7, so as to start machining the rear bevel foot 102. Then, when the apex of the bevel 101 of the When the lens comes into contact with the depth stop 26, the user verifies that the chosen depth of passage D1 corresponds to that desired. If it is not, it adjusts the height of the stop.

It then activates the actuating motor of the lens locking shafts 11, so that the grinding wheel mills the entire periphery of the rear bevel foot 102. When the entire periphery of the rear bevel foot 102 is machined, the user controls the stopping of the two motors and then extracts the ophthalmic lens 100 of the shafts 11 with the help of the knobs 13. The lens thus recovered is then easily fitted into the circle 110 of the selected frame, without no interference appears between the rear bevel foot 102 of the ophthalmic lens 100 and the trailing edge 112 of the inner face of the circle 110. If despite this recovery, interference remains, the user will be able to again install the lens in the device so as to re-machine its rear bevel foot with a greater depth of pass.

The present invention is not limited to the embodiments described and shown, but the skilled person will be able to make any variant within his mind.

In particular, it will be possible for the first elastic axial abutment means, making it possible to bias the ophthalmic lens against the grinding wheel, to be constituted by a simple compression spring threaded onto the shaft around which the rocker pivots, in compression between a part of the chassis and the right side of the rocker. This compression spring will then recall the rocker towards its left stop position, and thus to remind the rear flank of the bevel of the lens against the edge of the wheel.

In another variant, the first resilient axial abutment means for reminding the ophthalmic lens against the grinding wheel can directly act on the locking shafts of the lens. In this variant, the rocker has no translational mobility. On the other hand, the axial translation mobility of the shafts is used to elastically and synchronously return the two shafts to the left, so as to maintain the trailing edge of the bevel of the ophthalmic lens in contact with the edge of the grinding wheel.

It will also be possible to block the lens holder and the lens in axial translation with respect to the frame and to give the wheel an axial translational mobility relative to the lens along an axis substantially parallel to the locking axis. The first axial axial abutment means of the lens against the grinding wheel will then be arranged to return the machining tool in a direction opposite to the direction of the point P1.

Claims

1. A method of trimming an ophthalmic lens (100) comprising:

- A step of beveling this ophthalmic lens (100) to form on its edge a bevel (101) bordered by at least one rear foot bevel

(102)

a step of blocking the ophthalmic lens (100) bevelled in means for locking and driving in rotation (11, 12) around a locking pin (A1), and - a step of taking up the slice of the ophthalmic lens (100) locked in said rotational locking and driving means (11, 12), characterized in that said recovering step comprises machining the rear bevel foot (102), excluding the bevel (101) itself, on at least part of its surface, by means of a machining tool (7) whose working generator (A6) is inclined with respect to said locking axis (A1).

2. Method according to the preceding claim, wherein, during the recovery step, the rotation locking and driving means (11, 12) and / or the machining tool (7) are axially reclosed. along the blocking axis (A1), such that a trailing edge (103) of the bevel of the ophthalmic lens (100) bears against second abutment means (50; 51) associated with the tool machining (7).

3. The method as claimed in claim 1, in which, during the recovery step, the locking and rotational drive means (11, 12) along the blocking axis (A1) are axially biased. so that the periphery of the front face (104) of the ophthalmic lens (100) or a leading edge (106) of the bevel of the ophthalmic lens (100) abuts against first rigid stop means (30).

The method of one of the preceding claims, wherein said recovering step comprises machining all of the surface of the rear bevel foot (102).

5. Method according to one of the preceding claims, wherein during said bevelling step, the bevel is machined at the edge of the front face (104) of the ophthalmic lens (100), so that the slice of this ophthalmic lens (100) is devoid of front bevel foot.

6. Method according to one of claims 1 to 4, wherein said step of beveling comprises, besides the machining of the rear bevel foot (102), the machining one foot before bevel (105).

7. Method according to one of the preceding claims, wherein the ophthalmic lens (100) has a front optical surface whose radius of curvature is less than 120 millimeters and / or a wafer whose maximum thickness is greater than 7 millimeters.

8. Apparatus for resuming the trimming of a beveled ophthalmic lens (100), comprising:

a chassis (2),

- a machining tool (7) rotatably mounted on the frame (2) about an axis of rotation (A3),

- a lens holder (10) mounted on the frame (2) and provided with locking means and rotational drive (11, 12) of the ophthalmic lens (100) around a locking pin (A1), and

- mechanical connection means (3, 4, 14) of the lens holder (10) and / or the machining tool (7) relative to the frame (2) allowing a variation of the spacing between the locking pin (A1) and the machining tool (7), characterized in that the machining tool (7) has a working generator (A6) inclined with respect to said locking pin (A1) and it comprises means of mobility (3) to allow axial mobility of the ophthalmic lens (100) relative to the machining tool (7) along said locking pin (A1) and first stop means axial (30) rigid or elastic, during machining, oppose the axial displacement of the ophthalmic lens (100) locked in the locking means and rotational drive (11, 12) in the opposite direction to point (P1) of the locking pin (A1) which is closest to the work generator (A6), and / or oppose the movement of the machining tool (7) in the direction of this poi nt (P1).

9. Device according to the preceding claim, wherein said first axial abutment means (30) are resilient and recall, during machining, the ophthalmic lens (100) locked in the locking means and rotational drive (11). , 12) towards said point (P1) and / or recall the machining tool (7) in the direction opposite to said point (P1).

10. Device according to the preceding claim, wherein said first axial abutment means (30) are arranged to exert a force on the front face (104) of the ophthalmic lens (100), along an axis substantially parallel to the axis of blocking (A1), so as to maintain a trailing edge (103) of the bevel (101) of said ophthalmic lens (100) in contact with second means of stop (50; 51) associated with the machining tool (7).

11. Device according to the preceding claim, wherein said second abutment means are formed by a flank (51) or an edge of the machining tool (7).

12. Device according to one of the two preceding claims, wherein said second abutment means (50) are non-abrasive and / or rotatable relative to the machining tool (7) about the axis of rotation. (A3).

13. Device according to claim 8, wherein said first axial abutment means (30) are rigid and axially adjustable along the blocking axis (A1).

14. Device according to the preceding claim, comprising elastic return means (4) of the ophthalmic lens (100) against the first axial abutment means (30).

15. Device according to one of claims 8 to 14, wherein said first axial abutment means (30) comprise a roller (33) adapted to bear against the ophthalmic lens (100) to roll on the periphery of the face. front optic (104) of this ophthalmic lens (100).

16. Device according to one of claims 8 to 15, comprising a transverse stop depth of pass (26) adjustable which is adapted to cooperate by transverse contact with the bevel (101) of the ophthalmic lens (100) locked in said means for locking and rotating drive (11, 12) to limit the machining depth capability of the machining tool (7).