EP0176401B2 - Grinding machine for the guided or free bevelling or grooving of an ophthalmic lens - Google Patents

Description

The present invention relates generally to the beveling, or grooving, of an ophthalmic lens.

As is known, when, for the retention of an ophthalmic lens, the circle or surrounding of the spectacle frame in which it is to be mounted annularly has a groove, commonly called a bezel, it is necessary to ensure the formation, on the peripheral edge of such an ophthalmic lens, after trimming it at the contour of said circle or surrounding, of a rib, or bevel, generally of triangular cross section, suitable for its engagement in said groove of this latest.

Similarly, it is advisable to ensure the formation of a groove there, when the circle or surrounding of spectacle frame concerned comprises, for its maintenance, a tongue and / or a wire.

In what follows, and for the sake of convenience, we will most often stick to the only bevel necessary for the formation of a rib, or bevel, it being understood however that the operations concerned may also relate to the grooving necessary for the formation a groove.

In practice, this beveling, as well as the overhanging which precedes it, is carried out on a machine commonly known as a grinding machine, comprising, at a machining station, on a frame, a first support spindle, which carries at least one grinding wheel beveling or grooving, and which is rotatably mounted under the control of a drive motor, and a second support pin, which arranged parallel to the first, and rotatably mounted like this, is suitable for axially enclosing a lens ophthalmic to the right of said beveling wheel or grooving, for contact, by its edge, of said ophthalmic lens therewith.

It is of course important that the bevel formed on an ophthalmic lens treated with such a grinding machine is actually on the edge thereof, between the edges of its periphery.

In practice, to take into account both the proper curvature of such an ophthalmic lens and its possible variation in thickness, in particular when it is a lens with continuously variable focal power, called progressive, as well as du meniscus 〉〉 which, moreover, presents by itself the circle or entourage in which it is to be mounted, that is to say of the proper curvature of this circle or entourage, it is necessary to move the lens parallel to its axis during of its rotation relative to the beveling grinding wheel, so that its point of contact therewith describes a suitable trajectory between the edges of its periphery.

In other words, provision must be made for a capacity for relative axial displacement between the two support pins concerned, that carrying the ophthalmic lens, and that carrying the beveling wheel.

The relative axial displacement thus to be applied to one of these support pins, called here for simple convenience, movable support pin, can be provided manually.

This presupposes, on the part of the operator, a certain dexterity, the corresponding beveling of the ophthalmic lens being done simply by sight.

The result is therefore always relatively approximate.

The relative axial displacement of the movable support spindle can, as a variant, be done freely, by using a bevel wheel with a double slope in the groove of which this lens penetrates by the whole of its edge and therefore automatically centers itself permanently.

However, in practice, such an arrangement, which is advantageously particularly simple and easy to implement, is only suitable for relatively thin ophthalmic lenses with uniform curvature.

In fact, when it is a question, for example, of treating an ophthalmic lens with a thick edge, and in particular a toric ophthalmic lens, the width which the double slope beveling wheel to be used must have becomes rapidly prohibitive. .

As a corollary, when it is for example the treatment of a progressive ophthalmic lens, and therefore of variable thickness around its periphery, the bevel to be formed can 〈〈 go out 〉〉 from the limits of this periphery in the thinnest zone of the lens concerned, or in other words, inadvertently failing in this thin area.

This is why, for the constitution of grinding machines suitable for the treatment in particular of such lenses, it has been proposed to control, or, in other words, guide, by an appropriate servo, the relative axial displacement of the two support pins, so that the point of contact of the ophthalmic lens with the beveling wheel describes a determined trajectory.

Various control modes can be envisaged.

The grinding machine described in the French patent application filed on October 18, 1983 under No. 83 16574 (see FR-A-2 553 323), to which the present invention is more particularly. but not necessarily exclusively, intended, implements one, among others.

In any case, it is obvious that for a relatively thin and uniformly curved ophthalmic lens, such a servo-guided bevel is redundant.

In practice, it would be interesting for the practitioner to have a grinding machine allowing, as desired, either a free bevel, or a guided bevel.

The object of the present invention is precisely such a grinding machine.

This grinding machine, which is therefore intended for bevelling or grooving an ophthalmic lens, is of the type comprising, at a machining station, on a frame, as described for example in French patent application No. 83 16574 mentioned above, a first support spindle, which carries at least one beveling or grooving wheel, and which is rotatably mounted under the control of a drive motor, and a second support spindle, which, arranged parallel to the first, and rotatably mounted like this, is suitable for axially enclosing an ophthalmic lens in line with said beveling wheel or grooving, for contact, by its edge, of said ophthalmic lens with the latter, at least one said support pins, said for convenience movable support spindle, being also movably mounted on the frame parallel to its axis, in association with advancing means which, using a motor, are capable of ensuring a guided displacement thereof parallel to said axis, this grinding machine being characterized in that the advance means associated with the movable support spindle comprise a threaded rod which is locked in rotation on the output shaft of the motor, and a threaded drive member with which meshes said threaded rod, in that, between this movable support spindle and said feed means associated therewith, disengageable connection means are established capable of allowing, on request, either an effective axial displacement control of said movable support spindle by said advance means for guided beveling or grooving, or its release at least relative to them for beveling or free grooving, and in that, the spindle of s upport mobile being carried by a member, said here by simple convenience support member, and the feed means associated therewith jointly comprising a member, said here by simple convenience drive member, the disengageable connection means established between said mobile support spindle and said advance means comprise, on the one hand, two flanges which, established, at a distance from each other, transversely to the axis of said mobile support spindle, are integral with any one of said members, and, on the other hand, between said flanges, abutment means which, carried by the other of said members, are mounted movable thereon between a retracted, release position, for which they are at a distance from the flanges, and a deployed, connecting position, for which they are braced therebetween, thereby making it possible to secure the drive member with the support member.

Admittedly, in document FR-A-2 481 635, a grinding machine is described, the motor of which constituting the advance means associated with the movable support spindle operates either as torque motor or as brake motor, either as a freely rotating driven element, depending on the tension which is applied to it, so that it is already possible to make either a guided bevel, a free bevel or an associated bevel.

However, if such an engine constitutes, if need be, disengageable connecting means, it is not intended that it can ensure positive blocking of the driven member.

It is not the same with the disengageable connection means used according to the invention, thanks to the stop means that they comprise.

Indeed, for an effective connection of the mobile support spindle with the advance means which are associated with it, it suffices to pass these stop means into the deployed position, and, for the release of this mobile support spindle, it just pass them into the retracted position.

In both cases, this is an advantageously simple, easy and quick operation.

Preferably, this operation is carried out by means of a DC motor.

It is thus advantageously possible, if a resumption of grinding is to be ensured on an ophthalmic lens, to find for the same the same indexing, and therefore to avoid any untimely damage to the bevel already formed on its edge.

• la figure 1 est une vue, partie en plan, partie en coupe, d'une machine à meuler suivant l'invention;
• la figure 2 en est une vue en coupe axiale, suivant la ligne brisée II-II de la figure 1 ;
• la figure 3 en est, avec des arrachements, une vue en élévation latérale, suivant la flèche III de la figure 2;
• la figure 4 est, à échelle supérieure, une vue partielle en plan de la machine à meuler suivant l'invention, suivant la flèche IV de la figure 3 ;
• la figure 5 en est, à l'échelle de la figure 4, une vue partielle en coupe, suivant la ligne brisée V-V de cette figure 4;
• la figure 6 en est, à la même échelle, une autre vue partielle en coupe, suivant la ligne VI-VI de la figure 5, pour la position déployée des moyens de butée qui y sont mis en oeuvre ;
• la figure 7 an est une vue partielle en coupe analogue à celle de la figure 6, pour la position rétractée de ces moyens de butée.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:

• Figure 1 is a view, partly in plan, partly in section, of a grinding machine according to the invention;
• Figure 2 is an axial sectional view along the broken line II-II of Figure 1;
• Figure 3 is a cutaway view, in side elevation, along arrow III of Figure 2;
• Figure 4 is, on a larger scale, a partial plan view of the grinding machine according to the invention, according to arrow IV of Figure 3;
• Figure 5 is a scale view of Figure 4, a partial sectional view along the broken line VV of this Figure 4;
• Figure 6 is, on the same scale, another partial sectional view, along the line VI-VI of Figure 5, for the deployed position of the stop means which are implemented therein;
• Figure 7 year is a partial sectional view similar to that of Figure 6, for the retracted position of these stop means.

In these figures, we recognize a grinding machine of the type described in French patent application No. 83 16574 mentioned above.

This grinding machine will not be described in full detail here.

In practice, only those of these constituents necessary for understanding the invention will be described more fully.

In the embodiment shown, it is a question, overall, of ensuring the formation, on the peripheral edge of an ophthalmic lens 10, of a rib, or bevel, suitable for its engagement in the groove, or bezel, of the circle or circle of the spectacle frame in which it is to be mounted.

The grinding machine used for such beveling generally comprises, at the corresponding machining station, on a frame 13, a first support spindle 15, which carries at least one beveling wheel 16, and which is rotatably mounted under the control of a drive motor 17, and a second support pin 18, which, arranged parallel to the first, and rotatably mounted like this, is suitable for axially enclosing the ophthalmic lens 10, at right of the beveling wheel 16, for contact, by its edge, with the latter.

In a manner known per se, this second support pin 18 is formed, in practice, of two half-pins 18A, 18B, suitable for enclosing between them the ophthalmic lens 10 which they must carry, one of these half-pins 18A, 18B being for this purpose mounted axially movable relative to the other and axially lockable in position relative to the latter.

For the beveling of the ophthalmic lens 10, the beveling wheel 16 comprises, in its median zone, a groove with a V cross section 34.

It is arranged in overhang, at the end of the support pin 15 which carries it.

To confer an axial displacement capacity relative to the ophthalmic lens 10 to be treated with respect to the beveling grinding wheel 16, at least one of the support pins 15, 18, referred to here simply as a movable support pin, is movably mounted on the frame 13, parallel to its axis, in association with advance means adapted to ensure a guided movement parallel to said axis.

In the embodiment shown, as in the French patent application No. 83 16574 mentioned above, it is the support pin 15 carrying the beveling wheel 16.

To this end, this support pin 15, and, with it, the beveling wheel 16 and its drive motor 17, are carried by a member 36, said here for simple convenience, support member, mounted movably on the frame 13 , parallel to the axis of the support pin 15, along the double arrow F2 in FIGS. 1, 2.

In the embodiment shown, this support member 36, or carriage, is, for this purpose, engaged with two guides 38 carried, parallel to themselves, by the frame 13.

For reasons which will appear below, it comprises laterally, a sole 56, which extends in overhang parallel to the frame 13, at a distance from the latter.

At the same time, the advance means associated with the movable support spindle 15 comprise a member 40, said here for simple convenience, drive member, in practice a simple threaded nut, and a threaded rod 41 which, rotatably mounted on the frame 13, is locked in rotation on the output shaft of a stepping motor 44.

According to the invention, between the movable support spindle 15 and the advance means thus associated with the latter, disengageable connection means 57 are established, suitable for allowing, on request, either an effective axial displacement control of said movable support pin 15 by said advancing means, that is to say its release at least relative with respect thereto.

In practice, these disengageable connection means 57 comprise, on the one hand, two flanges 58, which, established, at a distance from each other, transversely with respect to the axis of the movable support pin 15, are integral with any one of the members 36, 40, specified above, and, on the other hand, between said flanges 58, stop means 59, which, carried by the other of said members 36, 40, are mounted movable thereon between a retracted position, release, for which they are spaced from the flanges 58, and a deployed position, connection, for which they are arcboutés therebetween.

In the embodiment shown, the flanges 58 are integral with the drive member 40, while the associated stop means 59 are carried by the support member 36, and, more precisely, by the sole 56 that includes this one, this sole extending to this effect beyond the threaded rod 41 of the associated advancing means, between this threaded rod 41 and the frame 13.

In the embodiment shown, the stop means 59 comprise two strips 60, which, mounted movable in opposite directions relative to each other, parallel to the axis of the movable support pin 15, are each respectively adapted, in the deployed position, FIG. 6, to come into abutment, by one of their transverse ends, against the flanges 58.

In practice, these two strips 60 are thus mounted movable synchronously on the support member 36 which carries them, and they are for this purpose each respectively secured to two racks 62, which, each arranged respectively on either side of the same control pinion 63 rotatably mounted on said support member 36, mesh with each other with the latter.

This control pinion 63 is wedged on the output shaft 64 of a geared motor 65, which is also carried by the support member 36, and whose motor 66 is preferably a DC motor.

The control of this motor 66 is available to the user.

In practice, the racks 62 are attached to the strips 60 by screws 68, FIG. 5, and these strips 60 are each respectively slidably mounted in two guides 69 belonging to the support member 36 which carries them, and more precisely, to a part 70, in the form of a yoke, attached itself, by a sole 71, and by means of screws 74, on the sole 56 which comprises said support member 36.

It is this same piece in the form of a yoke 70 which carries the geared motor 65, on the back of its central part 72, and the control pinion 63, which is rotatably mounted on its said central part 72, extends between its wings 73, each comprising the guide 69 associated with the corresponding strip 60.

Preferably, and as shown, for each strip 60, that of the flanges 58 opposite that with which it cooperates in support in the deployed position has, to its right, that is to say in its extension, a clean passage 75 to his engagement.

Finally, one of the strips 60, in practice that furthest from the frame 13, carries, projecting upwards, a pin 77, intended to cooperate, in abutment, with the bottom of a groove 78 formed for this purpose in the corresponding wing 73 of the yoke-shaped part 70 in which these slide bars 60 are slidably mounted.

For a first direction of supply of the direct current motor 66, the strips 60 come to bear against their respective flanges 58, moving, jointly, synchronously, but in opposite directions with respect to each other, following the arrows F4 in FIG. 6.

For the deployed position, of connection, which these strips 60 then occupy, the stop means 59 which they form jointly are braced between the flanges 58, and it follows that the support member 36 which carries them is linked in movement to these flanges 58.

It is therefore, in this case, the motor 44 which controls the relative axial displacement of the movable support pin 15 relative to the support pin 18, according to a so-called guided beveling mode of the ophthalmic lens 10 during treatment. .

On the other hand, for the opposite direction of supply of the DC motor 66, the strips 60 deviate from their respective flanges 58, according to the arrows F5 in FIG. 7.

This movement, which, in practice, is facilitated by their engagement in the corresponding passage 75 of the opposite flange 58, and which is, also in practice, limited by the abutment of the pin 77, against the bottom of the notch 78 corresponding to the yoke-shaped part 70 which carries them, leads them to a retracted, release position, for which, in FIG. 7, they are both spaced from their respective support flanges 58.

It follows that, within at least their abutment against the yoke-shaped part 70, these flanges 58, and therefore the support member 36 which carries them, are free to move parallel to the axis of the movable support spindle 15, without any interference with the feed means normally associated with the latter, in a so-called free beveling mode of the ophthalmic lens 10 during treatment.

Thus, it is advantageously possible, according to the invention, to implement a guided bevel or a free bevel, depending on the characteristics of the ophthalmic lens 10 to be treated.

To do this, it suffices to intervene accordingly on the DC motor 66.

Of course, the present invention is not limited to the embodiment described and shown, but it encompasses any variant.

In addition, its field of application is not limited to that of the only grinding machine described in French patent application No. 83 16574, but it extends on the contrary as well to any grinding machine in which the one of the support pins of the ophthalmic lens or of the beveling wheel is mounted movable relative to the other.

Finally, and as already indicated above, its field of application is not limited to that of the only beveling of the ophthalmic lenses concerned, but on the contrary extends equally to that of their grooving.

Claims (8)

1. A machine for bevelling or grooving an ophthalmic lens, of the type comprising, at a machining station, on a support structure (13), a first support spindle (15) which carries at least one bevelling or grooving grinding wheel (16) and which is mounted rotatably under the control of a drive motor (17), and a second support spindle (18), which, disposed parallel to the first support spindle and mounted rotatably like same, is capable of axially gripping an ophthalmic lens (10) in line with said bevelling or grooving grinding wheel (16), for contact by way of its edge of said ophthalmic lens (10) with same, one at least of said support spindles (15, 18), referred to hereinafter for the sake of convenience as the movable support spindle, also being mounted movably on the support structure (13) parallel to the axis thereof, in association with advance means, which, employing a motor (44), are capable of providing for guided displacement thereof parallel to said axis, characterised in that the advance means (40, 41) associated with the movable support spindle (15) comprise a lead screw (41) which is constrained to rotate on the output shaft of the motor (44), and a screwthreaded drive member (40) with which said lead screw (41) engages, in that disposed between the movable support spindle (15) and said advance means (40, 41) associated therewith are disengageable connecting means (57) capable of permitting on demand either effective control for axial displacement of said movable support spindle (15) by said advance means (40, 41) for guided bevelling or grooving, or the at least relative release thereof with respect to free bevelling or grooving, and in that the movable support spindle (15) being carried by a member (36), referred to here as the support member for the sake of convenience, and the advance means (40, 41) which are associated therewith jointly comprising a member (40), referred to here as the drive member for the sake of convenience, the disengageable connecting means (57) provided between said movable support spindle (15) and said advance means (40, 41) comprise two side plate portions (58), on the one hand, which, disposed at a spacing from each other transversely with respect to the axis of said movable support spindle (15), are fixed with respect to either one of said members (36, 40), and, on the other hand, between said side plate portions (58), abutment means (59), which, carried by the other of said members (36, 40), are mounted movably thereon between a retracted release position in which they are at a spacing from the side plate portions (58), and an extended connecting position in which they are braced between same, thereby enabling the drive member (40) to be fixed to the support member (36).
2. A machine according to Claim 1 characterised in that said abutment means (59) comprise two sliders (60), which, mounted movably in opposite directions to each other parallel to the axis of the movable support spindle (15), are each respectively adapted to come to bear against said side plate portions (58) in the extended position.
3. A machine according to Claim 2, characterised in that the two sliders (60) are mounted movably synchronously on the member (36) which carries them.
4. A machine according to Claim 3, characterised in that the two sliders (60) are each respectively fixed with respect to two racks (62) which both engage with one and the same control pinion (63) mounted rotatably on the member (36) which carries them.
5. A machine according to Claim 4, characterised in that said control pinion (63) is fixed on the output shaft (64) of a direct current motor (66).
6. A machine according to any one of Claims 2 to 5, characterised in that the two sliders (60) are each respectively mounted slidably in two guides (69) belonging to the member (36) which carries them.
7. A machine according to any one of Claims 2 to 6, characterised in that, for each slider (60) that one of the slide plate portions (58) opposite to that with which it cooperates by bearing thereagainst in the extended position has in line therewith a passage (75) for engagement thereof.
8. A machine according to any one of Claims 1 to 7, characterised in that the two side plate portions (58) are fixed with respect to the drive member (40), whilst the associated abutment means (59) are carried by the support member (36).

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