EP0654322B1 - Spectacle lens edging machine - Google Patents

Description

The present invention relates generally the machines used for the overflowing that it is normally necessary to apply by machining to a glass of glasses to adjust the outline to that of the circle or entourage of glasses frame that he must equip.

It more specifically targets that of these machines which includes at least one cutting tool, such as a grinding wheel or cutter, rotatably mounted on a frame, rocker, mounted pivoting on this frame around an axis parallel to the axis of cutting tool rotation, support spindle, mounted rotating on the rocker around an axis also parallel to the axis of rotation of the cutting tool and adapted to receive, axially, perpendicular to the cutting tool, the glass to be machined, and, at a distance from this glass, a template, and, carried by the frame plumb with this template, to provide support for the scale through it and so stop at a rating of instruction to respect the relative engagement movement of the lens compared to the cutting tool, a key, commonly called vernier head.

The template can be directly around the circle or entourage of spectacle frame to be fitted, and, in this case, the key can be fixed.

But, as a variant, the template can be of outline circular, and in this case the associated key is mounted mobile on the frame under the control of steering means which, restoring the form data transmitted to them by a contour reading device to which is corollarily subject the circle or entourage of spectacle frame to be fitted, impose at any time on this key, for an orientation given angularity of the support pin carrying the glass machining, a specified set point dimension.

In all cases, a charge should be ensured suitable support between the glass and the cutting tool.

This bearing load usually results from the effect combined with the weight of the scale and associated means works for this purpose.

These additional means include for example a counterweight mounted adjustable in position on the rocker transversely relative to the pivot axis thereof.

If this counterweight advantageously allows, in intervening on its lever arm, to vary according to the necessities the load of support which it induces, it has for disadvantage of being bulky and expensive.

The additional means used can also include elastic means.

To date, these elastic means, which are for example formed by a preloaded spring, are established between the rocker and the frame, and so they are actually likely to request this rocker in the direction of the key carried by the built.

But the support load they induce at the level of glass during machining is difficult to adjust, and it increases as the diameter of this glass decreases.

However, for at least some applications, and this is the case for example during the overflowing of a thin or fragile glass, it is desirable to have a support load relatively moderate and constant, while for others, and this is the case for example when spilling a glass standard, it is possible to initially implement a higher support load while accepting a possible subsequent variation thereof.

The present invention generally has for object a provision allowing to satisfy in a very simple to this double requirement.

More specifically, it relates to a machine to overflow for glasses of the kind comprising at least a cutting tool, such as a grinding wheel or a bur, which is rotatably mounted on a frame, a rocker, which is mounted pivoting on this frame around an axis parallel to the axis of rotation of the cutting tool, a support spindle, which is rotating climb on the scale around an axis also parallel to the axis of rotation of the cutting tool, and which is adapted to receive, axially, directly above the cutting tool, the glass to be machined, and, at a distance from this glass, a template, and, carried by the frame below this template, a touch, with, between the scale and the frame, elastic means capable to request this rocker in the direction of this key, this machine being generally characterized in that, the key being movably mounted on the frame, it is provided, between the rocker and it, in addition to the elastic means intervening between the scale and the frame and said below by simple convenience main elastic means, elastic means auxiliaries who are also likely to request the toggle direction of the key.

These auxiliary elastic means adding in service their effects to those of the main elastic means they are at the origin of an additional support charge.

For example, and preferably, this charge additional support is at most equal to a fraction of that due to the main elastic means.

But, due to the mobility of the button, it is advantageously possible to modulate it at will, by pulling so advantageously an additional part of this mobility.

For example, it is possible by construction to do so that when the gauge carried by the scale is at key contact, which corresponds in particular to the position of the scale when the machined glass has been overflowed at the level desired deposit, this additional support load is substantially zero.

As a result, it is still so when the template is only slightly deviated from the key.

To minimize, if desired, this support load complementary during machining, so it suffices to so that the key is only at a short distance at all times of the template, ordering its movement accordingly.

According to one embodiment of the invention, this key being precisely subject to moving control means, these are for this purpose themselves under the control of steering means allowing if desired to temporarily confer the key, for a given angular orientation of the support pin carrying the glass, a dimension in relation to the lower gauge at the set point normally to be observed for machining of this glass in this angular orientation of this pin of support.

In this case, the support load is not due for the main thing that only the main elastic means, the auxiliary elastic means somehow inhibited.

This support load is then substantially constant, and by construction it can be done relatively moderate, which is ideal for machining a glass fine or fragile.

The risk of breakage of such thin or fragile glass is are therefore advantageously limited.

Instead of postponing the implementation as before from the key to the setpoint normally to be observed, it is possible, on the contrary, for the machining of a standard glass, to bring the key directly to this setpoint dimension.

The additional support load induced by the means auxiliary elastic then takes its full value, while decreasing as the machining progresses.

This results in an advantageous saving in machining time for such a standard glass.

In all cases, only intervenes at the end of machining the bearing load due only to the main elastic means, since the additional support charge due to the means auxiliary elastic is then substantially zero.

This advantageously results, at this stage of the machining, better respect for shapes and dimensions.

It is advantageously possible, moreover, to draw use of the main elastic means to ensure the maintenance in the raised rest position of the scale between two machining operations.

For this, it suffices to locate their point of action on the rocker beyond the pivot axis thereof by relative to their point of attachment to the frame.

la figure 1 est une vue en perspective d'une machine à déborder suivant un mode de réalisation de l'invention, pour une position de fin d'usinage de sa bascule ;

la figure 2 en est, à échelle supérieure, une vue de bout, suivant la flèche II de la figure 1, pour la position relevée de repos de sa bascule ;

la figure 3 en est une vue de bout analogue à celle de la figure 2 pour une position quelconque de la bascule lors de l'usinage d'un verre standard ;

la figure 4 en est une vue de bout également analogue à celle de la figure 2 pour la position de fin d'usinage de la bascule ;

la figure 5 en est, à la manière de la figure 3, une vue de bout pour une position quelconque de la bascule lors de l'usinage d'un verre fragile.

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 perspective view of a machine to overflow according to one embodiment of the invention, for an end of machining position of its rocker;

Figure 2 is a larger scale, an end view, along arrow II of Figure 1, for the raised position of rest of its rocker;

Figure 3 is an end view similar to that of Figure 2 for any position of the rocker when machining a standard glass;

Figure 4 is an end view also similar to that of Figure 2 for the end of machining position of the lever;

Figure 5 is, in the manner of Figure 3, an end view for any position of the rocker when machining a fragile glass.

As illustrated in these figures, it is, overall, to ensure by machining the overflow of a glass of glasses 10 on a overflowing machine 11 to allow the mounting in one of the circles or surroundings of a mounting of determined glasses not shown.

In a manner known per se, the overflowing machine 11 comprises, overall, at least one cutting tool 12, such like a grinding wheel or a milling cutter, for example, which of a motor 13, is rotatably mounted on a frame not shown in all its details, along an axis of rotation A1 shown diagrammatically in broken lines in FIG. 1, a rocker 14, which, according to the double arrow F in FIG. 1, is pivotally mounted on the frame around an axis A2 parallel to the axis of rotation A1 of the cutting tool 12 and shown diagrammatically in broken lines in Figure 1, a support pin 15, which is mounted rotating on the rocker 14 around an axis A3 too shown schematically in broken lines in Figure 1 and him too parallel to the axis of rotation A1 of the cutting tool 12, and which is adapted to receive, axially, on the one hand, directly above the cutting tool 12, the glass 10 to be machined, being, by example, and as shown, formed of two half-pins 15 ', 15' 'suitable for axially enclosing this glass 10 previously slipped accordingly, and, on the other hand, to distance from the lens 10, and according to the arrangements described more in detail later, a template 16, and, carried by the frame directly above this template 16, a key 17, commonly called vernier head.

In the embodiment shown, the template 16 is of circular outline, and, jointly, and along arrangements described in more detail later, the key 17 is movably mounted on the frame.

For example, and as shown, the template 16 is a drum fitted on the support pin 15 at the end of this one.

Alternatively, it may be a simple disc.

Only has been shown elsewhere in the figures, for simplification of these, part of the frame, in the species a set square 18.

The key 17 is carried by this square 18, while being subjected to displacement control means 20.

In the embodiment shown, these means movement control 20 comprises a nut 21, which carries the key 17 or forms by itself such a key 17, a screw 22, with which the nut 21 is in screw connection and which is rotatably mounted on the frame, and, more precisely, on the bracket 18, and a motor 23, which is also carried by this bracket 18, and whose output shaft 24 provides the driving of the screw 22 or forms by itself such a screw 22.

More specifically, in this embodiment, the nut 21 effectively forms the key 17 by itself, and, likewise, the output shaft 24 of the motor 23 actually forms by itself the screw 22.

Preferably, the nut 21 and the screw 22 form together what is commonly called a ball screw.

Between the scale 14 and the frame intervene by elsewhere elastic means 25 liable to stress this rocker 14 in the direction of key 17.

In the embodiment shown, these means elastic 25, here called main elastic means, are constituted by a simple preloaded tension spring and hitched to rocker 14 at one end and square 18 to the other of these.

Preferably, and as shown, the point action of these main elastic means 25 on the rocker 14, materialized by a stud 26 provided laterally projecting thereon, parallel to its pivot axis A2, is located beyond this pivot axis A2 with respect to their attachment point 27 on the frame, and more precisely on square 18.

It follows that, by crossing a position of neutral point corresponding to the pivot axis A2 of the flip-flop 14, these main elastic means 25 can indifferently either solicit effectively this rocker 14 in the direction of key 17, and this is of course the case during the machining of a glass 10, as shown in the figures 3 to 5, or, on the contrary, request rocker 14 in the direction opposite key 17, and this is the case for the position rest reading shown in figure 2.

By construction, it is preferably made in so that for this raised position of rest of the rocker 14, the main elastic means 25 are relaxed.

According to the invention, there is provision, between the rocker 14 and the key 17, in addition to the main elastic means 25 intervening between this seesaw 14 and the frame, means auxiliary elastic bands 28 which are also liable to stress rocker 14 in the direction of key 17.

In the embodiment shown, these means auxiliary elastic 28 consist of a simple spring of traction hitched to the rocker 14 at one of its ends and key 17 to the other of these.

For example, this tension spring is coupled to one from its ends to the support pin 15 which the flip-flop 14, and, at the other end, it is coupled to a stud 29 provided laterally projecting for this purpose on the nut 21 forming the key 17, parallel to this pin support 15.

By construction, and in particular by an appropriate choice tension springs thus implemented, it is made in so that the support load induced at the glass 10 by the auxiliary elastic means 28 is at most equal to only a fraction of that induced by elastic means main 25.

For example, this fraction is around a third.

More specifically, in an embodiment giving particularly satisfied, the force exerted on the scale 14 by the tension spring constituting the elastic means main 25 is around 3 kg, while that exerted by the tension spring constituting the means auxiliary elastic 28 is of the order of approximately 1 kg.

But, of course, the numerical values as well specified should in no way be considered as limiting of the invention.

Preferably, it is made so that, when the template 16 carried by the rocker 14 is in contact with the button 17, the support load induced at the glass 10 by the auxiliary elastic means 28 is substantially zero.

This is the case, in particular, in the raised position of rest of the rocker 14 shown in Figure 2, which, in practical, is obtained by an appropriate command of the key 17, the latter pushing the flip-flop accordingly 14 until its pivot axis A2 is crossed by the tension spring constituting the elastic means main 25.

Thus, in this raised position of rest of the rocker 14, both this tension spring and that constituting the auxiliary elastic means 28 are relaxed.

Let D1 be the distance then existing between the points attachment of the auxiliary elastic means 28, materialized one by the support pin 15 and the other by the stud 29.

We will first assume, with reference to Figures 3 and 4, that the glass 10 to be machined is a standard glass sufficiently robust.

For each angular orientation of the spindle support 15 carrying this glass 10, the button is placed directly 17 at the set point normally to be observed for machining of it.

For example, and as shown in Figure 1, the displacement control means 20 of this key 17 can to this end be under the control of steering means 30 their restoring the shape data they receive from a device contour reading not shown.

These control means 30 not falling under the present invention, they will not be described here.

Anyway, it results from the deposit rating applied to key 17 that this key 17 deviates from the template 16 and that the attachment points of the tension spring constituting the auxiliary elastic means 28 are themselves spaced from each other by a distance D2, figure 3, upper at the previous distance D1.

This tension spring is then tensioned, and it adds therefore its effects to those of the tension spring constituting the main elastic means 25.

As the glass 10 is machined, the distance D2 decreases, until, at the end of machining, and such as shown in Figure 4, it takes the value of the previous distance D1.

The tension spring constituting the means auxiliary elastic 28 is then relaxed again, and the bearing load at glass 10 is no longer due only to only main elastic means 25.

We will now assume, with reference to FIG. 5, that the glass 10 to be machined is a thin or fragile glass.

For any given angular orientation of the spindle support 15, the key 17 is then temporarily given a dimension with respect to the gauge 16 less than the dimension of Normally set to respect for the machining of glass 10 in this angular orientation of the support pin 15.

The corresponding distance D'2 is therefore less than the previous distance D2.

In other words, it is made so that the distance D3 between key 17 and template 16 remains systematically low throughout the machining of the glass 10.

Of course, the control means 30 are established Consequently.

In other words, they are established in such a way as to allow to temporarily give key 17 a dimension lower than the set point.

Thus, throughout the machining of the glass 10, the tension spring constituting the elastic means auxiliary 28 is relaxed, or practically relaxed.

In other words, throughout its machining, the glass 10 is only subject to the support load induced by the means main elastic 25, the auxiliary elastic means 28 being somehow inhibited.

Of course, the present invention is not limited to the embodiment described and shown, but encompasses any variant in the context of the following claims.

Claims (7)

1. An edge-trimming machine for a spectacles lens of the kind comprising at least one cutting tool (12) such as a grinding tool or a milling cutter which is mounted rotatably on a support, a rocker member (14) which is mounted pivotably on said support about an axis (A2) which is parallel to the axis of rotation (A1) of the cutting tool (12), a support spindle (15) which is mounted rotatably on the rocker member (14) about an axis (A3) which is also parallel to the axis of rotation (A1) of the cutting tool (12) and which is adapted to receive axially in line with the cutting tool (12) the lens (10) to be machined and at a spacing from said lens (10) a template (16) and, carried by the support in line with said template (16), a contact member (17) with, between the rocker member (14) and the support, resilient means (25) capable of urging said rocker member (14) towards said contact member (17), characterised in that, the contact member (17) being mounted movably on the support, provided between the rocker member (14) and the contact member (17), in addition to the resilient means (25) operatively disposed between the rocker member (14) and the support and referred to hereinafter for the sake of simple convenience as main resilient means, are auxiliary resilient means (28) which are also capable of urging said rocker member (14) in the direction of said contact member (17).
2. An edge-trimming machine according to claim 1 characterised in that the support load induced at the location of the lens (10) by the auxiliary resilient means (28) is at most equal only to a fraction of that induced by the main resilient means (25).
3. An edge-trimming machine according to claim 2 characterised in that said fraction is of the order of a third.
4. An edge-trimming machine according to any one of claims 1 to 3 characterised in that, when the template (16) carried by the rocker member (14) is in contact with the contact member (17), the support load induced at the location of the lens (10) by the auxiliary resilient means (28) is substantially zero.
5. An edge-trimming machine according to any one of claims 1 to 4 characterised in that, the contact member (17) being subject to means (20) for controlling displacement thereof, said displacement-control means are themselves under the control of pilot-control means (30) which make it possible temporarily to impart to the contact member (17), for a given angular orientation of the support spindle (15) carrying the lens (10), a dimension with respect to the template (16) which is less than the reference dimension which is normally to be complied with for machining the lens (10) in that angular orientation of said support spindle (15).
6. An edge-trimming machine according to any one of claims 1 to 5 characterised in that, the contact member (17) being subject to means (20) for controlling displacement thereof, said displacement-control means (20) comprise a nut (21) which carries the contact member (17) or which by itself forms such a contact member (17), a screw (22) with which said nut (21) is in screwing engagement and which is mounted rotatably on the support, and a motor (23) whose output shaft (24) provides for driving the screw (22) or by itself forms such a screw (22).
7. An edge-trimming machine according to any one of claims 1 to 6 characterised in that the point of action (26) of the main resilient means (25) on the rocker member (14) is beyond the pivot axis (A2) thereof with respect to their point of attachment (27) to the support.

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