Alternative blocking

Abstract

Device for blocking a spectacle lens blank that has a finished surface and a machining surface, situated opposite the finished surface, for machining in a machining device. The device includes a receiving component having a convex, planar or concave receiving surface for blocking the finished surface of the spectacle lens blank, wherein the receiving component has an essentially flat counter-surface that is arranged opposite the receiving surface, and wherein the normal of the counter-surface is inclined by 1 to 10 counter to the normal at the middle point of the receiving surface.

Claims

1. A device for blocking a spectacle lens blank that has a finished surface and a machining surface, situated opposite the finished surface, for machining in a machining device, with the device comprising: a receiver having a convex, planar or concave receiving surface configured to block the finished surface of the spectacle lens blank such that an entire surface of the spectacle lens blank is joined with the receiving surface of the receiver, wherein the receiver has an essentially flat counter-surface that is arranged opposite the receiving surface, wherein the normal of the counter-surface is inclined by 1 to 10 counter to the normal at the middle point of the receiving surface.

2. The device according to claim 1, further comprising: a bearer having an essentially flat and inclined bearing surface relative to a machining axis of the bearer on which the receiver, which has a counter-surface, can be borne.

3. The device according to claim 2, wherein the bearing surface is inclined in a machining position so that the normal of the bearing surface is inclined by 1 to 10 relative to the predetermined machining axis of the bearer.

4. The device according to claim 3, wherein the receiver and the bearer are designed to be rotatable counter to one another so that the normal at the middle point of the receiving surface is arranged to be parallel with or at an incline relative to the machining axis of the bearer, and wherein a magnitude of the incline depends on a rotation position of the receiver relative to the bearer.

5. The device according to claim 4, wherein an inclination angle between the normal at the middle point of the receiving surface relative to the machining axis can be set from 0 to 20 via the rotation position of the receiver relative to the bearer.

6. The device according to claim 2, wherein the normal of the counter-surface is inclined by the same angle, counter to the normal at the middle point of the receiving surface, as the normal of the bearing surface relative to the machining axis of the bearer.

7. The device according to claim 2, wherein the receiver and the bearer are joinable with one another positively or non-positively.

8. The device according to claim 2, wherein the bearer is designed as a separate component.

9. The device according to claim 2, wherein the bearing surface of the bearer is designed as an integral component of the machining device.

10. The device according to claim 1, wherein the receiver is made of an easily machinable material.

11. The device according to claim 1, wherein the receiver is designed in the form of a concave spherical calotte.

12. The device according to claim 1, wherein, upon blocking the spectacle lens blank, the spectacle lens blank is machined by removing material from the receiver and the spectacle lens blank at the same time.

13. The device according to claim 1, wherein the normal at the middle point of the receiving surface, a machining axis of the bearer, and a finished surface of the spectacle lens blank have a common intersection point.

14. The device according to claim 1, wherein the spectacle lens blank is joined with the receiving surface of the receiver so as to be releasable, via gluing, adhesive tape, adhesion, at least one chemically curable material or via at least one material by means of a phase transition from liquid to solid.

15. A method for blocking a spectacle lens blank that has a finished surface and a machining surface, situated opposite the finished surface, for machining in a machining device, the method comprising: placing an essentially flat counter-surface of a receiver having a convex, planar or concave receiving surface onto an essentially flat and inclined bearing surface of a bearer, rotating the receiver relative to the bearer until the normal at the middle point of the receiving surface is inclined to be at an angle (+) relative to a machining axis of the bearer, and blocking a spectacle lens blank on the receiving surface such that, upon blocking the spectacle lens blank, an entire surface of the spectacle lens blank is joined with the receiving surface of the receiver.

16. The method according to claim 15, wherein the spectacle lens blank is joined with the receiving surface of the receiver so as to be releasable, via gluing, adhesive tape, adhesion, at least one chemically curable material or via at least one material by means of a phase transition from liquid to solid.

17. The method according to claim 15, further comprising: machining the spectacle lens blank by removing material from the receiver and the spectacle lens blank at the same time.

18. The method according to claim 15, wherein the normal at the middle point of the receiving surface, a machining axis of the bearer, and a finished surface of the spectacle lens blank have a common intersection point.

Description

(1) The invention is described in detail in the following using embodiments shown in Figures. Individual features of the exemplary embodiments shown in Figures may be transferred to other embodiments. Shown are:

(2) FIG. 1 a bearing component in the form of a clamping block as part of a device for blocking a spectacle lens blank;

(3) FIG. 2 a receiving component of a device for blocking a spectacle lens blank;

(4) FIG. 3 a two-part device for blocking, together with a spectacle lens blank in whose prescription surface no prism is to be introduced;

(5) FIG. 4 a two-part device for blocking, together with a spectacle lens blank in whose prescription surface a prism is to be introduced; and

(6) FIG. 5 a receiving component that is coupled to a bearing component by means of negative pressure.

(7) FIG. 1 shows a clamping block 1 as an exemplary embodiment of a bearing component of a device for blocking. A side view of the clamping block 1 is thereby shown in the left half of FIG. 1, whereas the right half of FIG. 1 shows a cross sectional view through the clamping block 1.

(8) The clamping block 1 is designed as a reusable bearing component. A central clamping block axis 2 through the clamping block 1 is designed and provided to serve as a predetermined machining axis of a spectacle lens blank. The clamping block 1 may be clamped in a machining device (not shown in Figures) so that the clamping block 1 is located in its machining position. The clamping block 1 is essentially cylindrical and is designed to be essentially rotationally symmetrical relative to the clamping block axis 2 as seen from a surface inclination (which is described in detail in the following). The clamping block axis 2thus the machining axis of the clamping block 1 as a bearing partmay, in the machining position, coincide with a work piece spindle axis of the machining device.

(9) The clamping block 1 furthermore has central alignment surfaces 3, rotary alignment surfaces 4 and axial alignment surfaces 5 that are respectively provided with regard to the central, rotational or axial alignment of the clamping block 1 in the machining device, relative to a tool spindle of the machining device.

(10) The central alignment surfaces 3 are thereby formed parallel to the clamping block axis 2 and are designed as a cylindrical shell of the clamping block 1. The cylinder end of the clamping block 1 (which is designed and provided to be clamped in the machining device) leads, after the cylinder shell formed by the central alignment surfaces 3, into three feet that taper in the direction of the clamp-side cylinder end of the clamping block 1. These tapering surfaces of the three feet are formed by the rotary alignment surfaces 4. The other cylinder end of the clamping block 1 that is situated on the opposite side from the clamp-side cylinder end is designed and provided to receive a spectacle lens blank via a receiving component (see FIG. 2). At this receiving-side cylinder end of the clamping block 1, the cylinder shell that is formed by the central alignment surfaces 3 leads into an annular disc surface that is arranged orthogonal to the cylinder wall, which annular disc surface is formed by the axial alignment surfaces 5. At this location, the diameter of the cylindrical clamping block is expanded via the axial alignment surfaces 5. The axial alignment surfaces 5 are formed orthogonal to the machining axis, thus the clamping block axis 2.

(11) A bearing surface inclined by a bearing inclination angle relative to the clamping block axis 2 borders the clamping block 1 at its receiver-side cylinder end. The bearing surface 6 is designed to be essentially flat and essentially disc-shaped. The middle point of the disc is arranged near the machining axis 2. The middle point of the disc should be offset from the machining axis 2 so that the rotation point of the receiving surface comes to lie on the machining axis. The bearing surface 6 is furthermore designed to be inclined so that the normal 7 of the bearing surface 6 is inclined by the bearing inclination angle relative to the clamping block axis 2. The normal of the bearing surface 6 is shown as a bearing axis 7 in FIG. 2.

(12) The bearing surface 6 is designed as a disc-shaped depression in the receiver-side cylinder end of the clamping block 1. The disc-shaped depression thus has a step-like elevation at its ring ends. The walls of this elevation are formed, in the shape of a cylindrical shell, as bearing component centering surfaces 8, wherein the bearing component centering surfaces 8 are arranged parallel to the bearing axis 7.

(13) FIG. 2 shows a receiving component 9 that is designed as a blank receiver or spectacle lens blank receiver. A side view of the receiving component 9 is thereby shown in the left half of FIG. 1, whereas the right half of FIG. 2 shows a cross sectional view through the receiving component 9.

(14) The receiving component 9 is essentially designed in the shape of a disc, wherein the disc surface is designed as a receiving surface 13 in the form of a bonding surface. The receiving surface 13 is concave and serves to receive and bear a finished surface of a spectacle lens blank upon blocking. For this, the receiving surface 13 largely has the counter-shape of the finished surface of a spectacle lens blank to be machined, which normally corresponds to a sphere.

(15) The disc surface of the receiving component 9 that is situated opposite the receiving surface 13 is designed as an essentially flat and circular counter-surface 10. The normal 11 of the counter-surface 10 is inclined by a receiving inclination angle relative to the normal 14 at the middle point of the receiving surface 13. The two normal 11 and 14 intersect in or near the intersection point of the normal 11 of the counter-surface 10 with the receiving surface 13.

(16) The counter-surface 10 is set off like a step from the remaining body of the receiving component 9. Receiving component centering surfaces 12 in the shape of a cylindrical shell are formed on the step, which receiving component centering surfaces 12 are designed parallel to the normal 11 of the counter-surface 10.

(17) The receiving component 9 shown in FIG. 2 and the clamping block 1 shown in FIG. 1 are designed and provided to be used as a two-part device for blocking. The two components are assembled for this, as this is shown in FIGS. 3 and 4.

(18) In a cross section through a block, FIG. 3 shows the clamping block 1 and the receiving component 9 in a state in which they are assembled and connected to one another. A spectacle lens blank 15 is arranged and blocked on the receiving surface 13 of the receiving component 9.

(19) In an assembled state, the counter-surface 10 of the receiving component 9 lies with its entire surface on and in parallel with the bearing surface 6 of the clamping block 1. The normal 11 of the counter-surface 10 and the clamping block axis 2 as the machining axis are thereby arranged directly atop one another. For this, the bearing surface 6 is centered on the counter-surface 10 by means of the receiving component centering surfaces 12 and the bearing component centering surfaces 8. The bearing component centering surfaces 8 thereby surround the receiving component centering surfaces 12. For this, the cylinder radius of the cylindrical bearing component centering surfaces 8 is adapted to the cylinder radius of the cylindrical receiving component centering surfaces 12 and/or vice versa.

(20) The prism necessary for the machining may be adjusted via a rotation of the two components (receiving component 9 and clamping block 1) relative to one another. The inclination of the normal 14 of the receiving component 13 relative to the clamping block axis 2 is thereby dependent on the rotation position of the receiving component 9 relative to the clamping block 1. The inclination of the blocked spectacle lens blank 15 relative to the clamping block axis 2 is therefore also dependent on this relative rotation position.

(21) The clamping block 1 and the receiving component 9 are connected with one another positively or non-positively to form a block piece unit, so as to be releasable. The positive or non-positive connection may take place via elastic force, bolting, hydraulically, pneumatically or via negative pressure.

(22) The spectacle lens blank 15, with its finished surface 16 on the receiving surface 13 of the receiving component 9, is blocked via gluing, via adhesive tape, via adhesion, via chemically curable materials and/or via materials with phase transition from liquid to solid as a blocking material 17. This takes place after the receiving component 9 and the clamping block 1 have been set precisely on the prism to be produced via rotation movement counter to one another and have been fastened to one another. Therefore, for blocking it is sufficient to joinvia a relatively thin layerblocking material 17 with either a partial surface or over its entire surface with the receiving component 9 so as to be releasable.

(23) Due to the use of a thin layer of blocking material 17, the heat introduction or the shrinkage upon curing of the blocking material 17 is so slight that no noteworthy deformations occur in the alignment of the spectacle lens blank 15.

(24) For this, the two components of the device for blocking may preferably be designed so that the normal 14 of the receiving surface 13, the clamping block axis 2 and the finished surface 16 of the spectacle lens blank 15 have a common intersection point 18 (see FIG. 4).

(25) Furthermore, the bearing inclination angle between the clamping block axis 2 and the bearing axis 7 of the clamping block 1 may be made identical to the receiving inclination angle between the normal 11 of the counter-surface and the normal 14 of the receiving surface 13. In this embodiment, a prism of 0 dpt results if the clamping block axis 2 coincides with the normal 14 of the receiving surface 13 and the angles and mutually cancel (see FIG. 3).

(26) In this embodiment, the maximum prism that can be setwhich corresponds to the sum of bearing inclination angle and receiving inclination angle (see FIG. 4)results via a rotation of the receiving component 9 relative to the clamping block 1 by 180 out of this position. Any prism angle may be set with discrete stepping or continuously via rotation between the two positions.

(27) Analogous to FIG. 3, FIG. 4 shows the block made up of clamping block 1, receiving component 9 and spectacle lens blank 15. In contrast to the relative position that is shown in FIG. 3, the clamping block 1 and receiving component 9 are thereby rotated counter to one another so that the normal 14 of the receiving surface 13 is aligned at an incline counter to the machining axis 2 at the maximum adjustable inclination angle +, and the maximum prism for the processing is thus set.

(28) The unit made up of clamping block 1, receiving component 9 and spectacle lens blank 15 provides a block. By means of the clamping block 1, the block may be centered, axial and aligned in terms of its rotation position in a machining device (not shown). Furthermore, the machining forces may be transferred from the clamping chuck of the machine to the block. The prescription surface of the spectacle lens blank 15 and the lens positions necessary for the production of the lens (from the customer data (for example engraving positions)) are adapted to the rotation position of the resulting prism basis corresponding to the rotation of the receiving component 9 relative to the clamping block 1.

(29) The receiving component 9 may be comprised of a machinable material that is not environmentally harmful. The spectacle lens blank 15 is machined during the production of the prescription surface and/or of the outer contour. If the geometry of the spectacle lens to be produced requires it, the receiving component 9 that is joined with the spectacle lens blank 15 is also partially machined. Following this, the prescription surface is polished to a finish. If applicable, the outer contour of the spectacle lens blank 15 is only produced after the polishing. This has the advantage that the spectacle lens blank 15 may be polished away largely without edge defects since the polishing tool is supported by the receiving component 9 and is not tilted away over the lens edge.

(30) After finishing the prescription surface (and if applicable the outer contour), the spectacle lens is released from the receiving component 9 and supplied to possible additional refining steps.

(31) In an alternative embodiment, the clamping block 1 is omitted. In this embodiment, the bearing surface 6, the bearing axis 7 and the bearing component centering surface 8 are designed as components of the work piece spindle of the machining device.

(32) FIG. 5 shows a two-part device for blocking. A side view of the device is thereby shown in the left half of FIG. 5, whereas the right half of FIG. 5 shows a cross section through the device.

(33) FIG. 5 shows an embodiment of a two-part device for blocking in which the receiving component 9 is attached to the clamping block 1 non-positively by means of negative pressure so as to be releasable. After the inclination angle of the prism has been set via the rotation movement described above, the intervening space between the clamping block 1 and the receiving component 9 is bounded by a seal 19 and evacuated via a valve 20. The external overpressure then presses the counter-surface 10 and the bearing surface 6 onto one another and thus ensures the position of the two components of the device relative to one another via frictional engagement.

REFERENCE LIST

(34) 1 clamping block; bearing component 2 clamping block axis; machining axis 3 central alignment surface 4 rotational alignment surface 5 axial alignment surface 6 bearing surface 7 bearing axis 8 bearing component centering surface 9 receiving component 10 counter-surface 11 normal of the counter-surface 12 receiving component centering surface 13 receiving surface 14 normal at the middle point of the receiving surface 15 spectacle lens blank 16 finished surface 17 blocking material 18 intersection point 19 seal 20 valve bearing inclination angle receiving inclination angle