EP0995546B1 - Spanneinrichtung zum Festlegen eines Rohlings auf einer Brillenglasrand-Schleifmaschine - Google Patents

Description

The present invention relates to a device for tightening a puck on a machine for overflowing optical glasses. As defined in the preamble of claim 1. Such a device is described in document FR.A.2 226 824.

As we know, the overflowing of the spectacle lenses on the grinders require the maintenance of these relative to tools.

When overflowing, the glass must be held rigidly on an axis around which it is brought to be turned so as to allow the realization different radii constituting the shape to be obtained; this axis, which by example may correspond to the optical center of the patient's pupil or to the geometric center of the shape, does not coincide with the center of the puck; added to this, the wide variety of geometric shapes of surfaces concave and convex glasses shows that it is not possible to ensure the retaining of the puck by rigid interfaces.

Known devices for clamping a puck on a machine overflow the optical glasses of the type comprising two jaws for tightening the faces of the coaxial puck provided with support members intended to cooperate each with one of the faces of the puck, at least one of the jaws comprising a plate and a body, the plate carrying one of the support members and being mounted at articulation on the body, such an articulation assembly being of the ball joint type.

Of course, an assembly of this type makes it possible to grasp the perpendicular to the average tangent of the surface to be clamped whatever the inclination of this perpendicular and therefore accept all geometric shapes of glasses.

However, the problem arises of the transmission of a couple of rotation through a ball joint type; this transmission is limited to the friction that may exist between the male and female elements of the patella, friction which cannot be increased by increasing the tightening force which would lead to breaking or altering the puck, and which would harm the proper swiveling performance.

We have already proposed to ensure the transmission of a torque in a ball joint to ensure that the surfaces present "stick": besides that this transmission is not ensured in a very positive way, it has the disadvantage of requiring after each operation to "take off" manually the two components of the patella on pain of breakage of the glass.

It has also been proposed to associate the two spherical elements of the ball joint two pins arranged orthogonally: this arrangement leads to a torque transmission with too much angular play, measuring in degrees.

The invention aims to avoid these drawbacks and proposes a clamping device provided with a ball-type joint which allows increase the performance of the overflow machine in terms of speed of machining, fidelity of the forms, respect of the dimensions and the axis of the glass.

According to the invention, a device for tightening a puck on a extend beyond the optical glasses, of the type comprising two jaws for tightening the faces of the coaxial puck provided with support members intended to cooperate each with one of the faces of the puck, at least one of the jaws comprising a plate and a body, the plate carrying one of the support members and being mounted at articulation on the body, the articulation mounting of the plate on the body being produced by a male element, carried by one of the two plate-body parts and cooperating with a female housing provided in the other of the two parts, is characterized in that the male element is provided with at least three facets regularly distributed around an axis that it presents, each facets having a generally cylindrical shape whose generatrices extend orthogonally with respect to said axis, on either side of a same transverse plane, the female housing, of the blind type, carrying flat faces parallel to an axis which it presents, intended to cooperate each with one of the facets of the male element and axially limited by a bottom.

Preferably, the male element is provided with six facets and the housing female with six flat faces.

Advantageously, the bottom of the female housing is frustoconical; in variant, the bottom of the female housing is semi-spherical.

Advantageously, the support member carried by the plate is semi-elastic.

Preferably, the articulated mounting of the plate on the body is protected by a bellows stapled peripherally on one side on the plate and on the other on the body.

Advantageously, the male element is carried by the body and the housing female housed in the tray.

Preferably, one of the jaws being fixed and the other movable axially, it is the movable jaw which comprises the plate and the body.

According to one embodiment, the overflow machine comprising a a clamping pin, the body is hollow and suitable for mounting at the end of the clamping pin to which it is secured.

As a variant, the overflow machine comprising a clamping spindle, the body is formed by the end of the clamping pin.

To better understand the object of the invention, we will describe now, by way of example, purely illustrative and not limiting, a mode of embodiment shown in the accompanying drawings.

• la figure 1 montre en coupe le mors mobile d'un dispositif de serrage selon un mode de réalisation de l'invention dans sa position de repos ;
• la figure 2 représente en coupe, selon II-II de la figure 3, le corps seul du mors de la figure 1 ;
• la figure 3 est une vue en plan du corps de la figure 2, les figures 4 et 5 étant des vues de droite et de gauche par rapport à la figure 3, respectivement selon les flèches IV et V de la figure 3 ;
• la figure 6 représente en coupe, le plateau seul du mors de la figure 1 ;
• la figure 7 est une vue de droite par rapport à la figure 6 ;
• la figure 8 montre en coupe l'organe d'appui du mors de la figure 1 ;
• la figure 9 montre en coupe le mors de la figure 1 en position opérationnelle ;
• la figure 10 est analogue à la figure 1 et montre une variante.

In these drawings:

• Figure 1 shows in section the movable jaw of a clamping device according to an embodiment of the invention in its rest position;
• 2 shows in section, along II-II of Figure 3, the body alone of the jaw of Figure 1;
• Figure 3 is a plan view of the body of Figure 2, Figures 4 and 5 being views of the right and left with respect to Figure 3, respectively according to arrows IV and V of Figure 3;
• 6 shows in section, the plate only of the jaw of Figure 1;
• Figure 7 is a right view with respect to Figure 6;
• Figure 8 shows in section the support member of the jaw of Figure 1;
• Figure 9 shows in section the jaw of Figure 1 in the operational position;
• Figure 10 is similar to Figure 1 and shows a variant.

The clamping device according to Figures 1 to 9 comprises a clamping jaw 10 comprising in plate 11 and a body 12; the plate 11 carries a support member 13 intended to cooperate with the face concave 2 of a puck 1 to overflow; with the convex face 3 of the puck 1 cooperates another jaw, not shown, fixed, centered, like the jaw of clamping 10, on the axis 4 of the puck 1, here its optical axis; as known per se, the fixed jaw, not shown, carries an elastic support member, of the kind suction cup, on which the puck 1 is "crushed" by the clamping jaw 10 by through its relatively elastic support member 13.

Here, the body 12 is hollow and provided with a blind housing 15 cylindrical, through which the clamping jaw 10 is mounted on the nose 6 of a spindle 5, of the overflow machine, centered on the axis 4; a screw 14 of the needle type screwed into a threaded hole 16 which crosses the wall of the body 12 allows the body 12 to be joined to the nose 6 of the spindle 5.

The torque is transmitted by a radial pin not shown which is housed in a notch 34 of the body 12.

From its front transverse wall 17 which limits its blind housing cylindrical 15, the body 12 carries a male element 18 adapted to cooperate with a female housing 19 formed in the plate 11.

The male element 18 is provided with facets 20, here six in number, regularly distributed around its axis 21; each facet 20 has a generally cylindrical shape whose generatrices extend orthogonally to said axis 21: thus, the two facets 20 opposite visible in section in Figure 2 have their generatrices perpendicular to the plane of the figure; the generators, and therefore each facet 20, extend on either side of the same transverse plane 22, advantageously symmetrically with respect to this plane 22; preferably their section through the plane of Figure 2 is in an arc centered on the axis at point 23 of intersection by the axis 21 of said transverse plane 22.

The female housing 19 carries planar faces 24 parallel to the axis 25 that presents the plate 11; the female housing 19 carries as many faces 24, regularly distributed circumferentially, that there are 20 facets on the male element 18, each face 24 being intended to cooperate with each facet 20.

Here, the bottom 26 is of frustoconical shape, centered on the axis 25.

According to a variant not shown, the bottom 26 is of semi-spherical shape.

Here, the bottom 26 has a circular central opening 27 corresponding to the smaller diameter base when the bottom 26 is frustoconical shape.

On its face intended to be opposite the puck 1 to overflow, the plate 11 has an annular recess 31 intended to receive the support member 13 made of semi-elastic material; more specifically, the support member 13 includes a web 33 surrounded by an annular crown 32 intended to be housed in the annular recess 31 of the plate 11; here the central opening 27 from the bottom 26 of the female housing 19 facilitates the positioning of the member support 13; alternatively, the bottom of the female housing 19 is full and the member support 13 has only the crown 32.

Thanks to the articulation which has just been described, the plate 11 and the body 12 are integral in rotation, by cooperation of the facets 20 with the faces 24; in addition, this cooperation allows the plate 11 to move angularly relative to the body 12: the support member 13 that the plate 11 can therefore be applied to the concave face 2 of the puck 1 which let the angle of the mean tangent of this face be, as shown in Figure 9; moreover, the cooperation of the facets 20 of the male element 18 with the bottom 26 of the female housing 19 ensures the transmission of the clamping force along axis 4 whatever the angle in question.

Thus, the joint functions in the manner of a ball joint while securing in rotation the male element 18 of the body 12 and the female housing 19 of the plate 11. The presence of six facets and six faces, arranged hexagonally, opposite two to two, allows a symmetrical swiveling from the point of view of the angles of movement of the plate 11 relative to the body 12; moreover, this hexagonal arrangement leads to an articulation having practically no rotating game and the cost of realization is reasonable; by comparing, an even number of facets and faces greater than six requires a play in very tight rotation, which strikes the cost price.

Of course, variants are possible; a variant with three or five facets and three or five faces also works: the swiveling is easy around an axis parallel to the flat faces; elsewhere, the travel is limit ; however, the travel is not symmetrical depending on the direction of travel. A variant with four facets and four faces also works easily and symmetrically around an axis parallel to two parallel faces, elsewhere the travel being more limited.

The joint is advantageously protected by an elastic bellows 30 rubber surrounding it, even chips made during the overflowing; one end of the bellows 30 is stapled in a groove 28 presented by the body 12 and the other end in a groove 29 of the plate 11; this bellows 30 is preferably mounted in tension between the plate 11 and the body 12; he thus assembles these two pieces of simple and easy to dismantle while permanently ensuring the contact of the male element 18 on the bottom 26 of the female housing 19, the joint is therefore without axial play; it should also be noted that, thanks at the bellows 30, upon loosening, the plate 11 and the body 12 resume automatically their starting position for which they are coaxial, as shown in figure 1.

We can of course associate different trays with the same body: thus, in FIG. 10, the clamping device 100 comprises a body 12 similar to that of the previous device 10, and a plate 111 of diameter lower than that of the previous plate 11; the tray 111 is provided with a support member 113 and a female housing 19 adapted to cooperate with the male element 18 of the body 12; a bellows 130 assembles the plate 111 and the body 12.

In the examples shown, the body 12 is designed to be mounted on pin 5 of the overflow machine; alternatively, this is the end of the pin 5 itself which is shaped like the body 12.

We can also reverse the structures: so, as a variant, it's in the body 12 which the female housing 19 is formed and it is the plate 11 which carries the male element 18.

Claims (10)

1. Device for clamping a blank on a machine for trimming optical lenses, which machine includes two coaxial clamping jaws for clamping faces of the blank and in which machine each jaw is provided with bearing means adapted to cooperate with one face of the blank, at least one (10, 100) of the jaws including a plate (11, 111) and a body (12) the plate (11, 111) carrying one (13, 113) of the bearing members and being articulated to the body (12) by a male member (18) carried by one (12) of the two parts of the plate/body combination (11, 111, 12) and cooperating with a female housing (19) in the other of the two parts, characterized in that the male member (18) has at least three facets (20) evenly distributed about its axis (21), each facet (20) being generally cylindrical with generatrices orthogonal to said axis (21) on respective opposite sides of a common transverse plane (22), and the blind female housing (19) having plane faces (24) parallel to its axis and each of which is delimited axially by a bottom (26) and is adapted to cooperate with one of the facets (20) of the male member (18).
2. Device according to claim 1 characterized in that the male member (18) has six facets (20) and the female housing (19) has six plane faces (24).
3. Device according to either of claims 1 and 2 characterized in that the bottom (26) of the female housing (19) is frustoconical.
4. Device according to either of claims 1 and 2 characterized in that the bottom (26) of the female housing (19) is hemispherical.
5. Device according to any one of claims 1 to 4 characterized in that the bearing member (13, 113) carried by the plate (11, 111) is semi-elastic.
6. Device according to any of claims 1 to 5 characterized in that the articulation of the plate (11, 111) to the body (12) is protected by a bellows (30, 130) clipped peripherally at one end to the plate (11, 111) and at the other end to the body (12).
7. Device according to any of claims 1 to 6 characterized in that the male member (18) is carried by the body (12) and the female housing (19) is formed in the plate (11, 111).
8. Device according to any of claims 1 to 7 wherein one of the jaws is fixed and the other (10) is movable in the axial direction characterized in that the movable jaw (10) includes the plate (11, 111) and the body (12).
9. Device according to claim 8 for use when the trimming machine comprises a clamping spindle characterized in that the body (12) is hollow (15) and adapted to be mounted at the end (6) of the clamping spindle (5), to which it is fastened (14).
10. Device according to claim 8 for use when the trimming machine includes a clamping spindle (5) characterized in that the body is the end of the clamping spindle (5).

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