EP2686137A1

EP2686137A1 - Device for the fine machining of optically active surfaces on in particular spectacle lenses

Info

Publication number: EP2686137A1
Application number: EP12710659.9A
Authority: EP
Inventors: Holger Schäfer; Steffen Wallendorf; Udo Fiedler
Original assignee: Satisloh AG
Current assignee: Satisloh AG
Priority date: 2011-03-17
Filing date: 2012-03-15
Publication date: 2014-01-22
Anticipated expiration: 2032-03-15
Also published as: EP2686137B1; MX2013008844A; US9289877B2; CN103429386A; DE102011014230A1; US20130344778A1; WO2012123120A1; CN103429386B; BR112013022794A2

Abstract

There is disclosed a device (10) for the fine machining of optically active surfaces on in particular spectacle lenses, having a spindle shaft (32) which has a tool-holder portion (34) and is mounted in a spindle housing (36) such that it can rotate about a tool rotation axis (A), and having an electric rotary drive (38) which has a rotor (40) and a stator (42) and by means of which the spindle shaft operatively connected to the rotor can be driven in rotation about the tool rotation axis, while the tool-holder portion can be displaced axially in the direction of the tool rotation axis. A particular feature of this device is that the rotor and the stator and the spindle shaft are arranged coaxially in the spindle housing, which for its part is guided in a guide tube (44) in a defined axially displaceable manner (2) in the direction of the tool rotation axis, wherein the spindle shaft is in the form of a hollow shaft, via which the tool-holder portion, which is configured to hold a membrane chuck (46), can be subjected to a fluid, this bringing about in particular a very compact structure and allowing rapid axial compensating movements of the tool during fine machining.

Description

DEVICE FOR FINE PROCESSING OF OPTICALLY ACTIVE SURFACES, IN PARTICULAR GLASSES OF GLASSES

TECHNICAL AREA

The present invention relates generally to a device for fine machining of optically active surfaces according to the preamble of claim 1. In particular, the invention relates to a device for fine machining the optically effective surfaces of spectacle lenses, as in so-called "RX workshops", i. Production facilities for the production of individual spectacle lenses are widely used according to prescriptions. If the following example of workpieces with optically active surfaces of "lenses" is mentioned, including not only eyeglass lenses made of mineral glass, but also eyeglass lenses from all other common materials, such as polycarbonate, CR 39, HI index, etc., including plastic be understood.

PRIOR ART The machining of the optically effective surfaces of

Spectacle lenses can be roughly subdivided into two processing phases, namely first the pre-processing of the optically active surface to produce the prescription macrogeometry and then the fine processing of the optically effective surface to eliminate pre-processing traces and to obtain the desired micro-geometry. While the preprocessing of the optically effective surfaces of spectacle lenses takes place, inter alia, as a function of the material of the spectacle lenses by grinding, milling and / or turning, the optically effective surfaces of spectacle lenses during fine machining are usually subjected to fine machining. subjected to grinding, lapping and / or polishing process, what to use a corresponding machine.

Above all hand-fed polishing machines in RX workshops are usually designed as "twin machines", so that advantageously the two lenses of an "RX job" - a pair of glasses ^¬ glass recipe always consists of a pair of spectacle lenses - can be simultaneously finished. Such a "twin" polishing machine is known for example from the documents US-A-2007/0155286 and US-A-2007/0155287.

In this prior art polishing machine projecting two parallel, each rotatable about a rotation axis, but otherwise stationary workpiece spindles from below into a working space where they face two polishing tools, so that a polishing tool of a workpiece spindle and the other polishing tool of the other workpiece spindle is assigned. Each polishing tool is freely rotatably mounted on a spherical bearing at a projecting from above into the working space piston rod of a respective, arranged above the working space piston-cylinder arrangement by means of the respective polishing tool can be lowered or raised individually with respect to the associated workpiece spindle. The two piston-cylinder assemblies are further by means of a linear drive together in a direction perpendicular to the axes of rotation of the workpiece spindles with respect to a front side of the polishing machine moved back and forth and also by means of a pivot drive together around a

Tiltable pivot axis, which is also perpendicular to the axes of rotation of the workpiece spindles, but parallel to the front of the polishing machine. By means of the pivot drive, the angular position between the axes of rotation of the tools and workpieces can be preset before the tools are lowered by means of the piston-cylinder assemblies on the workpieces. During the actual polishing process the workpieces are rotationally driven, with the tools in working engagement with the workpieces being frictionally entrained by friction, while the linear drive causes the tools to be alternately moved back and forth with respect to the front of the polishing machine so that the tools are relatively small Travel back and forth across the workpieces (so-called "tangential kinematics"). Advantages of this "twin" polishing machine include the fact that it is constructed from inexpensive components in device-simple manner, is very ergonomic for a manual feed and also requires very little footprint in the RX workshop due to their extremely compact, very narrow design , It would be desirable, however, if other polishing methods could be performed on such a polishing machine. For example, the flexible polishing tools disclosed in EP-A-1 473 116, EP-A-1 698 432 and EP-A-2 014 412 are designed for polishing processes in which not only the workpiece but also the tool itself is rotationally driven, whereby the polishing times can be significantly shortened compared to polishing methods in which the tool is only carried by friction.

The DE-A-102 50 856 forming the preamble of claim 1 discloses in this connection a polishing apparatus (see FIGS. 5 to 9) with a rotary electrical drive for the polishing tool, which as such has a stator and a rotor, and with a pneumatic piston-cylinder unit for an axial deflection of the polishing tool along a longitudinal axis. Here, the arrangement of the rotary and

Axial drives so made that a rotatably mounted in a housing about a rotation axis spindle shaft assembly ("rotor" in the linguistic use of the above document), which at her extending from the housing end the actual polishing tool, is rotatably driven by a toothed belt drive of the electric rotary drive, which is laterally offset in the housing, arranged parallel to the axis of rotation; the pneumatic piston-cylinder unit and an associated axial guide, on the other hand, are integrated in the spindle shaft assembly, consequently with rotational drive, which is why the piston-cylinder unit for supplying pressure medium requires a compressed air rotary feedthrough. This polishing device has a relatively large space requirement, which is why it is not suitable for use in the above-described "twin" polishing machine.

Finally, in the subsequently published document DE-A-10 2009 041 442 of the same Applicant a device for fine machining of the optically active surfaces is disclosed in particular spectacle lenses, having a tool receiving portion having a spindle shaft which is rotatably mounted in a spindle housing about a tool axis of rotation , a rotary electric motor having a rotor and a stator, by means of which the spindle shaft operatively connected to the rotor revolves around the rotor shaft

Tool rotation axis is rotationally driven, and an adjusting device by means of which the tool receiving portion with respect to the spindle housing in the direction of the tool rotation axis is axially displaceable. A special feature of this device is that the rotor and the stator are arranged coaxially with the spindle shaft, wherein by means of the adjusting device at least the rotor together with the spindle shaft with respect to the spindle housing in the direction of the tool axis of rotation is axially displaceable, which in particular a very compact design conditionally.

For very large curvatures or larger changes in curvature over the circumference of the processed optically active surfaces that require larger Axialhübe the tool, the use of this device has its limits. Because spindle shaft and Rotor, which have a considerable mass, must be moved along with the respective Axialhub, possibly required rapid axial compensatory movements of the tool are not possible.

TASK

The invention has for its object to provide a device as simple and inexpensive as possible for fine machining of optically effective surfaces on particular eyeglass lenses, by means of example, a polishing tool driven in rotation and axially displaced - the tool should also be able to rapid axial compensation movements - and which is still very compact, so that they approximately in a very narrow-built "twin" polishing machine, such as The polishing machine described above, can be used.

PRESENTATION OF THE INVENTION

This object is achieved by the features specified in claim 1. Advantageous or expedient developments of the invention are subject matter of the claims 2 to 10.

According to the invention, in a device for fine machining optically effective surfaces on, in particular, spectacle lenses, (i) a spindle shaft having a tool receiving section, which is rotatably mounted in a spindle housing about a tool axis of rotation, and (ii) a rotor and a stator comprising having electric rotary drive, by means of which the spindle shaft operatively connected to the rotor is rotatably driven about the tool rotation axis, while the tool receiving portion is axially displaceable in the direction of the tool rotation axis; the rotor and the stator of the electrical see rotary drive and the spindle shaft disposed coaxially in the spindle housing, which in turn defined in a guide tube in the direction of the tool axis of rotation axially displaceable (linear adjusting Z) is guided, wherein the spindle shaft is formed as a hollow shaft via which the tool receiving portion designed to receive a membrane chuck tool can be acted upon with a fluid.

Characterized in that according to the invention, the rotor and the stator of the electric rotary drive are arranged together with the spindle shaft on one and the same axis, the device is advantageously compact. In addition, the spindle shaft can be directly rotated without any play or slip-prone transfer elements, such as gears, timing belts. Like. Required, which reduces the overall device complexity, significantly reduces the space requirement for this drive and also avoids transmission-related efficiency losses and wear , With respect to the axial adjustment of the tool quasi a division is provided according to the invention: First, the spindle housing - and thus provided on the spindle shaft tool receiving portion - guided axially displaceable in the guide tube in the direction of the tool axis of rotation, so that held in the tool receiving portion membrane chuck tool - rather slowly - can be moved over relatively large axial paths and positioned with respect to the workpiece to be machined. On the other hand, the tool receiving portion for receiving a membrane chuck tool, as it is known for example from the aforementioned publications EP-A-1 473 116, EP-A-1 698 432 and EP-A-2 014 412 executed executed there over the hollow spindle shaft can be acted upon by a fluid or pressure medium so that, for example, a polishing plate held on the membrane feed tool can respond to the respective processing requirements in accordance with fast or sensitive axial compensation. can execute operations, for example, when workpieces are processed with very large curvatures or larger changes in curvature over the circumference. In this context, it should be noted that, for example, for use of the device according to the invention in a polishing machine for spectacle lenses the

Axialbewegung the polishing tool should be as smooth as possible. This property is particularly important for the polishing of spectacle lenses with toric, atoric or progressive surfaces with high deviation from the rotational symmetry, so that the polishing tool always full or flat and with sensitive adjustable polishing force (or contact force) rests on the lens. If, in fact, the polishing tool would only lose its surface contact with the workpiece surface for a short time during its high-speed rotary motion, the coarser grains and agglomerates present in the polishing agent could cause the polished spectacle lens surface to become scratched.

Moreover, the coaxial arrangement of axial guide for the rather long axial tool movements (spindle housing in the guide tube) and pressure medium supply for the rather short axial tool compensation movements (hollow spindle shaft in the spindle housing) also requires a very compact design of the device. As a result, the device according to the invention is eminently suitable for use in e.g. the above-described "twin" polishing machine, so that using other polishing methods with rotationally driven polishing tools, the processing times can be significantly reduced (ie, divisor 2), without increasing the low complexity of this polishing machine over charge or their space or space requirement at all to enlarge.

In principle, the spindle housing can consist of one piece in the area of the spindle shaft and rotary drive. outward However, it is preferable for easy manufacture and assembly if the spindle housing has a motor housing in which the rotor and the stator of the rotary drive are arranged, and a shaft housing flanged thereto in which the spindle shaft is rotatably mounted.

In an expedient embodiment of the device according to the invention, the motor housing can also be closed by means of a cover having a through hole in which a rotary passage for the fluid is attached, which is in fluid communication with the hollow spindle shaft. Here, various measures are conceivable for fastening the rotary feedthrough on the cover, for example a screw connection. Preferably, the rotary feedthrough in the through hole of the lid but frictionally fixed by means of an elastic cable grommet, as they are available at low cost commercially.

In order to easily prevent od the leadership of the spindle housing in the guide tube by liquid polishing agent. Like. Damaged or damaged, may be arranged between the remote from the rotary drive end of the guide tube and the remote from the rotary drive end of the spindle housing, a bellows, the surrounds the spindle housing. Likewise, at the end remote from the rotary drive end of the spindle shaft, a sluice disc for a liquid finishing means may be mounted in order to easily the Drehabdichtung (such as a

Mating of labyrinth seal and radial seal) between spindle housing and spindle shaft to protect. For the axial guidance of the spindle housing in the guide tube also various measures are conceivable, eg ball bushings or air bearing bushes. However, since a special smoothness is not required (more) because the rapid tool (compensation) movements in the membrane chuck itself, it is in terms of longevity and cost preferred when the spindle housing is guided axially by means of a sliding ring in the guide tube.

Furthermore, it is particularly advantageous to use the above-described device in duplicate in a polishing machine for simultaneously polishing two lenses, which polishing machine (i) a machine housing defining a working space, (ii) two workpiece spindles projecting into the working space, over the two to be polished (Iii) a first linear drive unit, by means of which a first tool carriage is movable along a linear axis which runs essentially perpendicular to the workpiece axes of rotation, (iii) a first linear drive unit is rotatably drivable by means of a common rotary drive substantially parallel to each other iv) a swivel drive unit which is arranged on the first tool carriage and by means of which a swiveling yoke is pivotable about a swivel adjusting axis which runs substantially perpendicular to the workpiece axes of rotation and substantially perpendicular to the linear axis, and (v) a second linear drive unit, which is arranged on the pivot yoke and by means of the at least one second tool carriage along a linear adjusting axis is movable, which is substantially perpendicular to the pivoting adjusting axis; in such a way that the two devices, with their tool receiving portions, each projecting one of the workpiece spindles protrude into the working space and are flange-mounted with their respective spindle housing on the at least one second tool carriage, while the respective guide tube is attached to the pivot yoke, so that the tool Rotary axis of each device with the workpiece axis of rotation of the associated workpiece spindle forms a plane in which the respective tool rotation axis with respect to the workpiece Drehachge the associated workpiece spindle is axially displaceable and tiltable. Such a trained and equipped "twin" polishing machine is characterized not only by the fact that it is very compact - inasmuch as it is also easy to manually load - and in a very cost effective way many common drives uses, but in particular by the fact that the provided by the inventive devices movement possibilities, namely the active rotational movement possibility of the polishing tools mounted thereon, compared to the above-described prior art, the implementation of other, especially faster or more time-efficient polishing process allows.

In a particularly simple and cost-effective embodiment of the polishing machine, only a second tool carriage can be provided for the common axial movement of both spindle housings by means of the second linear drive unit. Due to the given axial mobility in the respective membrane chuck tool, each tool can still be adapted individually to the respective machined surface.

Finally, it is advantageous in particular with regard to once again a simple and cost-effective design of the polishing machine, if both the pivot drive unit and the second linear drive unit are commercial linear modules, each having a lifting rod which is driven by a spindle drive driven by a DC motor can be retracted or retracted. BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be explained in greater detail by means of a preferred embodiment with reference to the attached, partially simplified or schematic drawings. In the drawings show: Fig. 1 is a perspective view of a polishing machine for spectacle lenses obliquely from above / right front with two parallel, inventive devices for fine machining of the optically active surfaces of the lenses, to release the view of essential components or assemblies of the machine and to simplify the presentation in particular, the control panel and controls, parts of the cladding, door mechanisms and washers, the work and tool trays, utilities (including pipes, hoses and pipes) for electricity, compressed air and polish, the polishing agent return and the measuring, maintenance and safety equipment were;

Fig. 2 is an enlarged scale compared to FIG. 1, on

Machine frame aborted, perspective view of the polishing machine of FIG. 1 obliquely from above / left front, on the one hand left in Fig. 1 inventive device and an associated, flexible work space cover were omitted to the connection situation for the left in Fig. 1 inventive device illustrate, and on the other hand, the side walls and the front wall of the work space bounding sheet metal housing to release the view of two parallel workpiece spindles, each of which a workpiece spindle is assigned to each one of the devices according to the invention;

Fig. 3 is a scale enlarged relative to FIG. 2 again enlarged, perspective view of the polishing machine of FIG. 1 obliquely from above / behind right, where opposite to the illustration in Figure 2 additionally the machine frame was omitted; a front view of the polishing machine of Figure 1 in the scale of Figure 3 and with the simplifications of Fig. 3. a side view of the polishing machine of Figure 1 from the right in Figure 4, again in the scale of Figure 3 and with the simplifications of Figure 3, wherein in contrast to Figure 4 on the device according to the invention a membrane feed tool is mounted with polishing plate ..; 1 to 5 enlarged, perspective view of one of the devices according to the invention from the polishing machine according to FIG. 1, with membrane feed tool mounted thereon without polishing plate; a front view of the device according to the invention of Fig. 6; 6 is an enlarged sectional view of the device according to the invention from FIG. 6, corresponding to the section line VIII-VIII in FIG. 7; and Fig. 6 is a fragmentary sectional view of the device of Fig. 6 according to the section line IX-IX of Fig. 8, but with the device shown in an extended condition in which the membrane chuck tool mounted on the device and provided with a polishing plate is shown is in machining engagement, which by means of a block piece at a with ge dashed lines indicated workpiece spindle is added.

DETAILED DESCRIPTION OF THE EMBODIMENT

In Figs. 1 to 5 is - as a preferred application or use of a device 10 described below in detail for the fine machining of optically effective surfaces on workpieces, such. Spectacle lenses L (see Fig. 5) - a "twin" type polishing machine, i. for the simultaneous polishing of two lenses L numbered 12.

The polishing machine 12 generally has (i) a machine housing 16 bounding a working space 14, which is mounted on a machine frame 18, (ii) two work piece spindles 20 projecting into the working space 14, via which two lenses L to be polished by means of a common rotary drive 22 (see FIG FIGS. 3 to 5) can be driven in rotation about workpiece axes of rotation C 1, C 2 (C in FIG. 9) that run essentially parallel to one another, (iii) a first linear drive unit 24, by means of which a first tool carriage 26 moves along a linear axis X (iv) a pivot drive unit 28 which is arranged on the first tool shed 26 and by means of which a pivot yoke 30 can be pivoted about a pivoting adjusting axis B, which is substantially perpendicular to the workpiece axes of rotation Cl, C2 and substantially perpendicular to the linear axis X, (v) a z wide linear drive unit 29 which is arranged on the pivot yoke 30 and by means of which a second tool slide 31 can be moved along a further linear adjusting axis Z which is substantially perpendicular to the pivoting adjusting axis B, and finally (vi) two of those already mentioned above Devices 10. As will be explained in more detail below, in particular with reference to FIGS. 6 to 9, each of the devices 10 generally comprises (a) a spindle shaft 32 having a tool receiving portion 34 and a spindle housing 36 about a tool axis of rotation AI, A2 (A from Fig. 6) is rotatably mounted, and (b) an electric rotary drive 38 (see Fig. 8) having a rotor 40 and a stator 42 and by means of which the rotor 40 operatively connected to the spindle shaft 32 about the tool axis of rotation AI, A2 (A) can be driven in rotation. Significant features of the device 10 here are that the rotor 40 and the stator 42 of the electric rotary drive 38 and the spindle shaft 32 are arranged to save space coaxially in the spindle housing 36, which in turn in a guide tube 44 in the direction of the tool axis of rotation AI, A2 (A ) is axially displaceable (linear adjusting axis Z) is guided, wherein the spindle shaft 32 is formed as a hollow shaft, via which the tool for receiving a membrane chuck tool 46 running tool receiving portion 34 can be acted upon with a fluid - as will also be described in more detail below - So that, for example, a recorded on the membrane chuck tool 46 polishing plate 47 is able to quickly perform relatively small axial compensating movements (linear movements Z'l, Z'2 or linear movement Z 'from Fig. 6). According to FIGS. 1 to 5, the devices 10 are now flanged with their respective spindle housing 36 on the second tool carriage 31 of the polishing machine 12 and fastened with their respective guide tube 44 to the pivot yoke 30 of the polishing machine 12 that they with their Werkzeugaufnahmeab- sections 34th each associated with one of the workpiece spindles 20 protrude into the working space 14. In this case, the tool axis of rotation AI, A2 of each device 10 with the workpiece axis of rotation Cl, C2 of the associated workpiece spindle 20 forms an imaginary plane (perpendicular to the plane of FIG. 4 and parallel to the plane of FIG. 5) in which the respective tool - Rotary axis AI, A2 with respect to the workpiece axis of rotation Cl, C2 of the associated workpiece spindle 20 axially displaceable (linear axis X, linear adjustment axis Z) and tiltable (pivoting adjustment axis B). The tool receiving portion 34 of the spindle shaft 32 can not be seen in Fig. 5, because the membrane chuck tool 46 is received on the tool receiving portion 34, as also Figs. 6 to 9 illustrate.

The machine housing 16 mounted obliquely on the machine frame 18 according to, in particular, FIG. 2 is designed as a welded sheet metal housing, comprising a bottom plate 48, a cover plate 50, two side walls 52, a rear wall 56 bevelled towards a drain 54 provided in the bottom plate 48, and a front wall 58, which limit the total work space 14. While the side walls 52 and the front wall 58 are provided with windows 60, 48 are round recesses in the bottom plate

(Not shown in detail) for the passage of the workpiece spindles 20 and a drive shaft 61 of the rotary drive 22 and in the cover plate 50 elongated recesses 62 (see Figs. 2 to 4) for the passage of the devices 10 provided in the working space 14. The elongate recesses 62 also allow for axial back and forth movement of the devices 10 in the direction of the linear axis X, i. in the direction of the front wall 58 and away therefrom, wherein in each case a bellows cover 64 comprising a sliding plate 63 is provided as a flexible working space cover for sealing against the working space 14 in the illustrated embodiment. In this case, a hole in the respective sliding plate 63 is penetrated by the guide tube 44 of the respective device 10, wherein a rolling bellows 65 provides for a tiltable seal between the guide tube 44 and the sliding plate 63.

As can be clearly seen in particular in FIGS. 4 and 5, the workpiece spindles 20 are flange-mounted in the working space 14 from above on the base plate 48 and engage in each case with them a drive shaft 66 and an actuating mechanism 68 for a collet 70, by means of which a lens L locked on a block piece S can be clamped axially fixed and capable of rotation on the respective workpiece spindle 20 (compare FIGS. 5 and 9). With 72 fortified pneumatic cylinders of the actuating mechanisms 68 are numbered below the bottom plate 48, by means of which the collets 70 can be opened or closed in a known per se. Behind the rear wall 56, ie outside the working space 14 of the rotary drive 22 - in the illustrated embodiment, a speed-controlled asynchronous three-phase motor - also from above on the

Bottom plate 48 flanged. Below the bottom plate 48 pulleys 74 are further attached to the drive shafts 61, 66 of rotary drive 22 and workpiece spindles 20 and operatively connected by means of a V-belt 76, so that the rotary drive 22 at the same time both workpiece spindles 20 with a predetermined rotational speed can drive (workpiece axes of rotation Cl, C2 or C). As best seen in Figs. 2 to 4, the first linear drive unit 24 in the illustrated embodiment comprises a driven by a servo motor 78 via a clutch ball screw 80, which is accommodated in a mounted on top of the cover plate 50 guide box 82 on the first tool carriage 26 is guided. This in the

Essentially horizontal linear axis X is CNC-controlled; however, to simplify the illustration, the associated displacement measuring system is not shown. According to FIGS. 1 to 4, this is substantially U-shaped

Pivoting yoke 30 is articulated with its legs on the front end of the first tool carriage 26 in FIGS. 1 and 2, so that it can pivot about the pivoting adjusting axis B. At the rear end of the first tool slide 26 in FIG. 2 at the rear or in FIG. 5, the swivel drive unit 28 is articulated, so that it can pivot about an axis 84. In the illustrated embodiment, the swivel drive unit 28 is a commercially available linear module, as can be obtained, for example, from the company SKF under the name "lifting cylinder CARE 33". These linear modules, which are used in large numbers for example as automatic window openers or for the adjustment of hospital beds, have a lifting rod 86 which can be extended or retracted via a spindle drive (not shown in more detail) driven by a DC motor 88. Here, the self-locking of the spindle drive is so large that the lifting rod 86 remains in its once approached position even under greater axial loads when the DC motor 88 is turned off without it od a brake or the like. The lifting rod 86 of the

Pivoting drive unit 28 is now hinged with its end facing away from the DC motor 88 in a middle, in Figs. 1 to 4 upper portion of the U-shaped Schwenkj ochs 30, so that the lifting rod 86 relative to the pivot yoke 30 about a further axis 90 (see. Figs. 1 and 2) can pivot. Insofar it can be seen that in the case of the articulated chain formed as described above, a defined axial extension or retraction of the lifting rod 86 results in that the pivoting yoke 30 is pivoted in a defined manner about the pivoting adjusting axis B. As further shown in particular Figs. 1 to 3 are on both sides of the pivot yoke 30 on which the pivot drive unit 28 facing end face linear guide carriage 92 is mounted, which cooperate with respective associated linear guide rails 94, which in turn on both sides of the

Substantially V-shaped second tool carriage 31 are mounted on the side facing away from the pivot drive unit 28 end side. At the upper end of the second tool carriage 31 in FIGS. 1 to 5, a holder 96 for the second linear drive unit 29 is attached. The second linear drive unit 29 is in the illustrated embodiment. Example - as in the pivot drive unit 28 - also to a commercially available linear module, with a lifting rod 86 ', which via a DC motor 88' driven spindle drive (not shown in detail) can be extended or retracted ren. The lifting rod 86 'of the second linear drive unit 29 is now articulated with its end facing away from the DC motor 88' to two counter-holders 98, which in turn are attached to a central region of the U-shaped pivot yoke 30. In that regard, it can be seen that an axial extension or retraction of the lifting rod 86 'causes the second tool slide 31 guided on the pivot yoke 30 with respect to the

According to FIGS. 2 and 3 in particular, the second tool carriage 31 has on both sides a respective side wall 100, on which the spindle housing 36 of the respective one Device 10 is flanged. Furthermore, on both sides of the pivot yoke 30 close to the pivoting adjusting axis B, a fastening bracket 102 is attached to the pivot yoke 30 on which the guide tube 44 of the respective device 10 is mounted, as will be described in more detail below.

As far as the possibilities of movement of the membrane chuck tool 46 held on the device 10 are concerned, it should be noted at this point that the electrical rotary drive 38 of the device 10-in the illustrated exemplary embodiment a synchronous three-phase motor-is speed-controlled (tool axes of rotation AI, A2 resp A). The unit can be effected by means of the second linear drive unit 29 via the second tool carriage 31

By contrast, linear movement of the membrane chuck tool 46 in the direction Z held on the device 10 is an adjusting movement. This movement possibility is primarily used to (1) to position the membrane chuck tool 46 before the actual polishing process relative to the lens L (linear adjustment axis Z), whereupon the polishing plate 47 mounted on the membrane chuck tool 46 is brought into contact with the spectacle lens L by pressurizing the membrane chuck tool 46 via the hollow spindle shaft 32 (linear movements Z'1, Z'2 in FIG. 5 or Z ¹ from FIG. 6). and during the polishing operation is pressed with a predetermined force in the direction of the lens L to produce a polishing pressure, and (2) the membrane chuck tool 46 after polishing away again from the lens L. Accordingly, the above-described polishing machine 12 allows, for example, the following procedure, which should be described only for a lens L, because the second lens L of the respective "RX job" in an analogous manner and at the same time polished. After loading the polishing machine 12 with the membrane feed tools 46 and polishing plates 47 and the lenses to be processed L is first by means of

Pivoting drive unit 28, the angle of attack of the tool axes of rotation AI, A2 or A with respect to the workpiece axes of rotation Cl, C2 or C depending on the geometry to be machined on the lens L to a predetermined angle value set (pivot axis B). This angle of attack is not changed during the actual polishing. Then, the membrane chuck tool 46 is moved by means of the first linear drive unit 24 in a position in which it is opposite the lens L (linear axis X). Thereafter, the membrane chuck tool 46 is displaced axially by means of the second linear drive unit 29 in the direction of the lens L and positioned (linear control axis Z), whereupon the polishing plate 47 comes into contact with the lens L through pressurization of the membrane chuck tool 46 via the hollow spindle shaft 32 (linear movement Z'l, Z'2 or Z '). Now, the polishing agent supply is turned on, and the membrane chuck tool 46 with the polishing plate 47 and the lens L are rotated by means of the electric rotary drive 38 and the rotary drive 22 in rotation (tool axes of rotation AI, A2 or A; Rotary axes Cl, C2 and C, respectively). Preferably, a synchronous synchronization takes place between the tool and the workpiece; However, it is also possible to drive tool and workpiece in opposite directions and / or to rotate at different speeds. Now the membrane feed tool 46 is oscillated by means of the first linear drive unit 24 with relatively small strokes over the spectacle lens L (linear axis X), so that the polishing plate 47 is guided over different surface regions of the spectacle lens L. Here, the polishing plate 47 moves the

(Non-circular) geometry on the polished spectacle lens L also slightly up and down (linear movement Z'l, Z'2 or Z ').

Finally, after switching off the polishing agent supply and stopping the rotational movements of the tool and workpiece (tool axes of rotation AI, A2 or A, workpiece rotational axes C1, C2 and C, respectively), as well as pressure medium relief of the membrane chuck tool 46 via the hollow spindle shaft 32 lifted away from the spectacle lens L by means of the second linear drive unit 29 (linear adjusting axis Z). Finally, the membrane chuck tool 46 is moved by means of the first linear drive unit 24 into a position (linear axis X) which allows the lens L to be removed from the polishing machine 12 or the membrane chuck tool 46 and / or the polishing plate 47 to be changed. Although the movements in B and Z have been described above as purely adjusting movements which serve to position the respective membrane chuck tool 46 angularly or in the axial direction relative to the associated workpiece spindle 20 before the actual polishing operation, the drive units (swivel drive unit 28 , second linear drive unit 29) of course, the respective membrane chuck tool 46, of course, during the actual polishing processing, for example, continuously, if necessary or desired. The structure and function of the device 10 will be described in more detail below with reference to FIGS. 6 to 9.

According to FIGS. 8 and 9 in particular, the spindle housing 36 is designed in several parts, with a substantially cube-shaped motor housing 106 closed at the top by means of a cover 104 in FIG. 8, in which the rotor 40 and the stator 42 of the electric rotary drive 38 are arranged , and a flanged shaft-like shaft housing 108 flanged thereto, in which the spindle shaft 32 is rotatably supported via two bearings 110. 6 and 7 rear side or in Fig. 8 right side wall 112, the motor housing 106 is flanged to the side wall 100 of the second tool carriage 31 with the aid of screws (not shown), as shown in FIGS. 2 and 3 reveals , On the left and in Fig. 8, left side wall 114 of the motor housing 106 in FIGS. 6 and 7, a plug-in connection 116 for the electrical supply of the rotary drive 38 and associated signal / sensor cable is provided. In the lower part of Figs. 6 to 8, the hollow cylindrical guide tube 44 can be seen, which is connected at its upper end in these figures with a through hole having mounting plate 118, for example via an adhesive and / or clamp connection, which in turn means of in Figs 6 and 8 shown screws 120 is screwed from above on the associated mounting bracket 102 on the pivot yoke 30 of the polishing machine 12 to attach the guide tube 44 on the pivot yoke 30, as shown in Figs. 1, 2, 4 and 5. Near the lower end of the guide tube 44 in FIGS. 8 and 9, a sliding or guide ring 124 made of plastic is inserted into a radial groove 122 of the guide tube 44, which cooperates with a cylindrical outer peripheral surface 126 of the shaft housing 108 to the spindle housing 36 in the guide tube 44 largely radially play freely axially.

8 and 9 lower end of the shaft housing 108 extending through the guide tube 44, a ring member 128 is pushed, which is clamped by means of grub screws 130 (FIG. 8) on the outer peripheral surface 126 of the shaft housing 108, wherein a O-ring 132 between the outer peripheral surface 126 of the shaft housing 108 and the inner peripheral surface of the ring member 128 seals. Furthermore, between the remote from the rotary drive 38, i. 8 and 9 lower end of the guide tube 44 and the remote from the rotary drive 38, i. 8 and 9 lower end of the shaft housing 108 a bellows arranged 134 which surrounds the shaft housing 108 of the spindle housing 36. Here, the bellows 134 is fixed at its axial ends in each case by means of a clamping ring 136 and a clamping collar on the outer peripheral surface of the guide tube 44 and the ring member 128. On the side facing away from the rotary drive 38, i. In FIGS. 8 and 9, the lower end of the spindle shaft 32 extending through the shaft housing 108 is further fitted with a centrifugal disc 138 acting as a centrifugal force seal for the liquid polishing agent, likewise by clamping by means of grub screws 140 (FIGS 8th) . This holds the

Centrifugal disc 138 on the inner circumference a radial seal 142 which sealingly cooperates with an annular end face 144 (FIG. 9) of the shaft housing 108 and the inner peripheral surface of the ring member 128, and also forms with a sloping end face 146 of the ring member 128 a small gap 148, as well of Fig. 9 can be seen.

Inside the motor housing 106, the stator 42 of the electric rotary drive 38, the windings are hineu tet in Fig. 8, shed with the motor housing 106. The electric Rotary drive 38, which has a large, continuously controllable speed range, is air-cooled and has for this purpose in the upper region of the rotor 40, a fan (not shown). At its upper end, projecting into the motor housing 106 in FIG. 8, the spindle shaft 32 carries the rotor 40, which is rotatably connected thereto in a suitable manner, eg by means of a ring-clamping element 150 or another known shaft-hub connection is. The associated clamping screws 152 serve at the same time the attachment of the fan (not shown).

In Fig. 8 above the spindle shaft 32, the cover 104 of the motor housing 106 is provided with a central through-hole 154 in which a commercially available rotary feedthrough 156th

(Rotary connector) is attached to the fluid or pressure means for acting on the membrane chuck tool 46, which is in fluid communication with the hollow spindle shaft 32. Here, the rotary feedthrough 156 in the through hole 154 of the lid 104 by means of a commercially available elastic

Cable grommet 158 frictionally fixed.

The spindle shaft 32 has a continuous stepped bore 160 with three cylindrical bore portions 162, 164, 166, which increase in diameter from top to bottom in FIG. In the upper bore portion 162, the rotary feedthrough 156 is inserted. The central bore portion 164, which extends axially between the bearings 110 of the spindle shaft 32 in the axial direction, connects the upper bore portion 162 to the lower bore portion 166. The lower bore portion 166 eventually forms the tool receiving portion 34 for the membrane chuck tool 46 and is provided with a Radial groove 168 provided for receiving an O-ring 170, which ensures a seal between the spindle shaft 32 and diaphragm chuck tool 46. Finally, FIGS. 6 to 9 also show, by way of example, the membrane chuck tool 46 held on the tool receiving section 34 of the spindle shaft 32 by means of a grub screw 172 (FIG. 8). This can in principle correspond to the polishing tools disclosed in the above-mentioned publications EP-A-1 473 116, EP-A-1 698 432 and EP-A-2 014 412, to which reference is made at this point in terms of design and function Membrane feed tools 46 expressly referenced. In the present case, an actively driven spindle shaft 32, however, the rotational drive in the diaphragm chuck tool 46 is realized differently, not via the bellows 174 of the diaphragm chuck tool 46, but over the axially displaceable in the diaphragm chuck tool 46 guide member 176. Here, the guide member 176 is supported on his in the 8 and 9 upper end via a transverse pin 178 on two longitudinal pins 180 from which are attached to the main body 182 of the membrane chuck tool 46. A transverse pin 186 is likewise provided on its lower ball head end 184 in FIGS. 8 and 9, which engages with associated cutouts 188 (FIG. 9) in the ball head bearing 190. Finally, the polishing plate 47 is replaceably held on the membrane feed tool 46 via an interface 192. Such polishing plate 47 can be found, for example, the document DE-A-10 2007 026 841; the interface 192 essentially corresponds to the interface shown and described in DE-A-10 2009 036 981. In this respect, reference should be made at this point to the cited documents.

When the present document generally refers to "fluid", it is intended to include gases, such as e.g. Compressed air, or liquids, such as oil, are understood, which can be used as a pressure medium.

A device is disclosed for the fine machining of optically effective surfaces on, in particular, spectacle lenses, with a spindle shaft having a tool receiving portion, which is rotatably mounted in a spindle housing about a tool axis of rotation, and a rotary electric motor having a rotor and a stator, by means of which the spindle shaft operatively connected to the rotor is rotatably driven about the tool rotation axis, while the tool receiving portion in the direction of the tool axis of rotation is axially displaceable. A special feature of this device is that rotor and stator and the spindle shaft are arranged coaxially in the spindle housing, which in turn is guided axially displaceably defined in a guide tube in the direction of the tool rotation axis, wherein the spindle shaft is formed as a hollow shaft, via which for receiving a tool receiving portion running a membrane chuck tool can be acted upon with a fluid, which in particular requires a very compact design and allows rapid axial compensating movements of the tool during fine machining.

LIST OF REFERENCE NUMBERS

10 device

12 polishing machine

14 workspace

16 machine housing

18 machine frame

20 workpiece spindle

22 rotary drive

24 first linear drive unit

26 first tool carriage

28 swivel drive unit

29 second linear drive unit

30 swivel yoke

31 second tool carriage

32 spindle shaft

34 tool receiving section

36 spindle housing

38 electric rotary drive

40 rotor

42 stator

44 guide tube

46 Membrane feed tool

47 polishing plates

48 base plate

50 cover plate

52 side wall

54 outflow

56 rear wall

58 front wall

60 windows

61 drive shaft

62 recess

63 sliding plate

64 bellows cover 65 rolling bellows

66 drive shaft

68 operating mechanism

70 collet

72 pneumatic cylinders

74 Pulley

76 V-belts

78 servomotor

80 Ball screw 82 Guiding boxes

84 axis

86, 86 'lifting rod

88, 88 'DC motor

90 axis

92 linear guide carriage

94 Linear guide rail

96 holders

98 counterholds

100 side cheek

102 mounting bracket

104 Lid

106 motor housing

108 shaft housing

110 bearings

112 sidewall

114 sidewall

116 plug connection

118 mounting plate

120 screw

122 radial groove

124 sliding ring

126 outer peripheral surface

128 ring part

130 grub screw

132 O-ring 134 bellows

136 clamping ring

138 slinger

140 grub screw

142 radial seal

144 face

146 face

148 gap

150 ring clamping element

152 clamping screw

154 Through hole

156 rotary feedthrough

158 cable grommet

160 stepped bore

162 bore section

164 bore section

166 bore section

168 radial groove

170 O-ring

172 grub screw

174 bellows

176 Guide member

178 cross pin

180 longitudinal pin

182 basic body

184 ball-headed

186 cross pin

188 recess

190 ball bearing

192 interface

A tool rotation axis in general (speed-controlled)

AI rotary axis right tool (speed-controlled)

A2 Rotary axis left-hand tool (speed-controlled) B Swivel-positioning axis tool C Workpiece rotation axis general (speed-controlled)

Cl axis of rotation right workpiece (speed controlled)

C2 axis of rotation left workpiece (speed controlled) cc second optically effective surface

cx first optically effective surface

L spectacle lens

block material

S block piece

X Linear axis of the first tool carriage (position-controlled) Z Linear positioning axis of the second tool carriage

Z ¹ linear motion tool general (uncontrolled)

Z'l linear motion right tool (uncontrolled)

Z'2 linear motion left tool (uncontrolled)

Claims

1. Device (10) for fine machining of optically active surfaces (cc, cx) on in particular spectacle lenses (L), with a tool receiving portion (34) having a spindle shaft (32) in a spindle housing (36) about a tool rotation Axis (A) is rotatably mounted, and a rotor (40) and a stator (42) having electrical rotary drive (38), by means of which with the rotor (40) operatively connected to the spindle shaft (32) about the tool axis of rotation (A) is rotatably driven, while the tool receiving portion (34) in the direction of the tool axis of rotation (A) is axially displaceable, characterized in that the rotor (40) and the stator (42) of the electric rotary drive (38) and the spindle shaft (32) coaxial in the spindle housing (36) are arranged, which in turn in a guide tube (44) defined in the direction of the tool axis of rotation (A) axially displaceable (linear adjusting axis Z) is guided, wherein the spindle shaft (32) is formed as a hollow shaft, ü Via which the tool receiving section (34) designed to receive a membrane chuck tool (46) can be acted upon by a fluid.

2. Device (10) according to claim 1, characterized in that the spindle housing (36) has a motor housing (106) in which the rotor (40) and the stator (42) of the rotary drive (38) are arranged, and a flanged thereto Shaft housing (108) has up, in which the spindle shaft (32) is rotatably mounted.

3. Device (10) according to claim 2, characterized in that the motor housing (106) by means of a lid (104) is closed, which has a through hole (154) in which a rotary feedthrough (156) is attached to the fluid, the is in fluid communication with the hollow spindle shaft (32).

4. Device (10) according to claim 3, characterized in that the rotary feedthrough (156) in the through hole (154) of the lid (104) by means of an elastic cable bushing grommet (158) is frictionally fixed.

5. Device (10) according to one of the preceding claims, characterized in that between the rotary drive (38) facing away from the end of the guide tube (44) and the rotary drive (38) distal end of the spindle housing (36) a bellows (134) is that surrounds the spindle housing (36).

6. Device (10) according to any one of the preceding claims, characterized in that on the rotary drive (38) facing away from the end of the spindle shaft (32) has a centrifugal disc (138) is mounted for a liquid finishing agent.

7. Device (10) according to any one of the preceding claims, characterized in that the spindle housing (36) by means of a sliding ring (124) in the guide tube (44) is guided axially.

8. polishing machine (12) for simultaneously polishing two spectacle lenses (L), comprising

a machine housing defining a working space (14)

(16)

two workpiece spindles (20) projecting into the working space (14), via which two lenses (L) to be polished are rotatably drivable by means of a common rotary drive (22) about workpiece axes of rotation (Cl, C2) running essentially parallel to one another,

a first linear drive unit (24), by means of which a first tool carriage (26) is movable along a linear axis (X) which is substantially perpendicular to the workpiece axes of rotation (Cl, C2),

a pivoting drive unit (28) which is arranged on the first tool carriage (26) and by means of which a pivoting yoke (30) about a pivoting adjusting axis (B) is pivotable, which is substantially perpendicular to the workpiece axes of rotation (Cl, C2) and substantially perpendicular to the linear axis (X),

a second linear drive unit (29) mounted on the

Pivoting yoke (30) is arranged and by means of the at least one second tool carriage (31) along a linear adjusting axis (Z) is movable, which is substantially perpendicular to the pivoting adjusting axis (B), and

two devices (10) according to one of the preceding claims, each with one of the workpiece spindles (20) allocated to the working space (14), whose respective spindle housing (36) is flanged to the at least one second tool carriage (31), while the respective guide tube (44) is attached to the pivot yoke (30) so that the tool rotation axis (AI, A2) of each device (10) is level with the workpiece rotation axis (Cl, C2) of the associated workpiece spindle (20) forms, in which the respective tool rotation axis (AI, A2) with respect to the workpiece axis of rotation (Cl, C2) of the associated workpiece spindle (20) axially displaceable (linear axis X, linear adjustment axis Z) and tiltable (pivoting adjustment axis B) ,

9. polishing machine (12) according to claim 8, wherein only a second tool carriage (31) for common axial Verfah ren (linear adjusting axis Z) of both spindle housing (36) by means of the second linear drive unit (29) is provided.

10. polishing machine (12) according to claim 8 or 9, wherein it is a commercially available both in the pivot drive unit (28) and in the second linear drive unit (29)

Linear module acts, with a lifting rod (86, 86 '), which is about a driven by a DC motor (88, 88') spindle drive or retractable.