DEVICE FOR FINE PROCESSING OF OPTICALLY EFFECTIVE SURFACES ON, IN PARTICULAR, EYEGLASS LENSES

Abstract

A device for fine processing of optically effective surfaces on workpieces has a workpiece spindle which protrudes into a working space and by which a workpiece to be polished can be rotationally driven about a workpiece axis of rotation. Two tool spindles are associated with the workpiece spindle and protrude into the working space oppositely to the workpiece spindle. On each tool spindle, a polishing tool can be rotationally driven about a tool axis of rotation and is retained so that the polishing tool can be axially advanced along the tool axis of rotation. Furthermore, the tool spindles can be moved together in relation to the workpiece spindle along a linear axis extending substantially perpendicularly to the workpiece axis of rotation and can be pivoted about different pivoting adjustment axes, which extend substantially perpendicularly to the workpiece axis of rotation and substantially perpendicularly to the linear axis.

Claims

1. A device for fine processing of optically effective surfaces of, spectacle lenses as workpieces, comprising a workpiece spindle, which projects into a work space and by way of which a workpiece to be polished is drivable for rotation about a workpiece axis of rotation, and two tool spindles which are associated with the workpiece spindle and project oppositely into the work space and on each of which a respective polishing tool is mounted to be drivable for rotation about a tool axis of rotation and to be axially adjustable along the tool axis of rotation, the tool spindles being movable in common relative to the workpiece spindle along a linear axis extending substantially perpendicularly to the workpiece axis of rotation and being pivotable about different pivot setting axes extending substantially perpendicularly to the workpiece axis of rotation and substantially perpendicularly to the linear axis, wherein the tool spindles are arranged one behind the other as seen in the direction of the linear axis.

2. A device according to claim 1, wherein the pivot setting axes lie in a notional plane extending along the linear axis or parallel thereto.

3. A device according to claim 1, wherein one tool spindle is mounted on a front pivot yoke, which is pivotably connected with a tool carriage to be capable of defined pivotation about one pivot setting axis, whereas the other tool spindle is mounted on a rear pivot yoke, which is pivotably mounted on the tool carriage to be capable of defined pivotation about the other pivot setting axis the carriage in turn being guided with respect to a frame, which surrounds the work space, to be drivable along the linear axis.

4. A device according to claim 3, wherein provided for movement and positioning of the tool carriage, which is guided on two guide rods connected with the frame, is a rotary drive which is stationary with respect to the frame and disposed in drive connection with a ball screw drive having a rotatably mounted ball screw spindle which engages a nut connected with the tool carriage to be secure against relative rotation.

5. A device according to claim 3, wherein provided for defined pivotation of the two tool spindles about the pivot setting axes is a linear drive which is pivotably connected by one end thereof with one pivot yoke at a spacing from the corresponding pivot setting axis and by the other end thereof with the tool carriage, and wherein the one pivot yoke is drivingly connected with the other pivot yoke by way of a coupling rod which, at a spacing from the pivot setting axes, is pivotably connected by one end thereof with the one pivot yoke and by the other end thereof with the other pivot yoke.

6. A device according to claim 1, wherein each tool spindle has for axial adjustment of the respective polishing tool along the associated tool axis of rotation a piston-cylinder arrangement with a piston, which is received in a cylinder housing and which is connected in coaxial arrangement with a spindle shaft to be effective for actuation, the spindle shaft together with the piston-cylinder arrangement being mounted in a spindle housing to be rotatable about the respective tool axis of rotation.

7. A device according to claim 6, wherein the piston-cylinder arrangement is pneumatically actuable, and wherein the cylinder housing of the pneumatically actuable piston-cylinder arrangement is of two-part construction and lined by a guide sleeve of mineral glass in which the piston, which at its guide surface is made from a graphite material, is received to be longitudinally displaceable.

8. A device according to claim 6, wherein the piston of the piston cylinder arrangement is tension-resistantly and compression-resistantly connected with the spindle shaft by way of a thin rod of spring steel.

9. A device according to claim 6, wherein the cylinder housing is provided at the outer circumference with a toothing for engagement of a cogged belt which is drivable by way of a motor, which is flange-mounted on the respective pivot yoke, with a belt pulley so as to rotate the piston-cylinder arrangement and thus the spindle shaft about the respective tool axis of rotation.

10. A device according to claim 6, wherein provided for torque transmission from the cylinder housing of the piston-cylinder arrangement to the spindle shaft is a splined shaft guide with guide grooves formed in the spindle shaft and a flange nut which is engaged with the grooves by way of an axial bearing element and which is connected with the cylinder housing to be secure against relative rotation.

11. A device according to claim 6, wherein the polishing tool comprises a tool mounting head which is securable to the respective spindle shaft to be capable of axial and rotational entrainment and on which a polishing disc is exchangeably mounted, for which purpose a base body of the polishing disc and the tool mounting head are provided with complementary structures for axial detenting and for rotational entrainment of the polishing disc by the tool mounting head.

12. A device according to claim 11, wherein the tool mounting head has a ball joint with a ball head, which is received in a ball socket and which is formed on a ball pin securable to the spindle shaft of the respective tool spindle, the ball socket being formed in a mounting plate with which the polishing disc is detentable.

13. A device according to claim 12, wherein the ball head has a receiving bore for a transverse pin which extends through the ball head and engages on either side of the ball head with associated recesses in the ball socket so as to connect the mounting plate with the ball pin to be capable of rotational entrainment.

14. A device according to claim 12, wherein the mounting plate is so resiliently supported by way of a resilient annular element on a support flange at the ball pin side that the polishing disc detented with the mounting plate seeks to self-align by its center axis with the ball pin and thus the spindle shaft of the respective tool spindle.

15. A device according to claim 11, wherein the tool mounting head in axially retracted setting of the spindle shaft is detentable by means of a detent device with the cylinder housing or a part connected therewith to be secure against relative rotation.

16. A device according to claim 15, wherein the detent device comprises a plurality of spring projections which are distributed over the circumference of the tool mounting head and project along the respective tool axis of rotation and which mechanically positively engage with lugs in an annular groove formed at the cylinder housing or the part connected therewith to be secure against relative rotation.

17. A device according to claim 1, wherein a lower region of the work space into which the workpiece spindle projects is bounded by a trough which is integrally deep-drawn from a plastics material and has step-free wall surfaces.

18. A polishing machine for simultaneous polishing of at least two spectacle lenses, comprising a machine frame in which in correspondence with the number of spectacle lenses to be simultaneously polished at least two devices are arranged, each device having a workpiece spindle, which projects into a work space and by way of which a workpiece to be polished is drivable for rotation about a workpiece axis of rotation, and two tool spindles which are associated with the workpiece spindle and project oppositely into the work space and on each of which a respective polishing tool is mounted to be drivable for rotation about a tool axis of rotation and to be axially adjustable along the tool axis of rotation, the tool spindles being movable in common relative to the workpiece spindle along a linear axis extending substantially perpendicularly to the workpiece axis of rotation and being pivotable about different pivot setting axes extending substantially perpendicularly to the workpiece axis of rotation and substantially perpendicularly to the linear axis, wherein the tool spindles are arranged one behind the other as seen in the direction of the linear axis.

19. A polishing machine according to claim 18, wherein the devices are arranged adjacent to one another so that the respective linear axes extend substantially parallel to one another.

20. A polishing machine according to claim 18, with a transfer station, which optionally has a conveyer belt, for deposit of prescription boxes for reception of spectacle lenses which are to be polished and which are polished, a washing station for washing the polished spectacle lenses and a portal handling system, which automatically transports the spectacle lenses between the stations and the devices and positions the spectacle lenses in the respective station or device.

21. A polishing machine according to claim 20, wherein the portal handling system comprises a three-dimensionally movable suction unit for holding a spectacle lens, which is to be polished, at the optically effective surface to be polished and a three-dimensionally movable multi-finger gripper for holding a polished spectacle lens at the edge thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention is explained in more detail in the following by way of a preferred embodiment with reference to the accompanying, partly simplified or schematic drawings, which are not to scale and in which:

[0042] FIG. 1 shows a perspective view of a polishing machine for spectacle lenses obliquely from above and front right with three parallelly arranged devices according to the invention for fine processing of the optically effective surfaces of the spectacle lenses as polishing cells, a spectacle lens washing station adjacent thereto on the right, a conveyor belt for prescription boxes and a portal handling system for transport of the spectacle lenses, wherein to provide a view of significant components or subassemblies of the machine and for simplification of the illustration, in particular, the operating unit and control, parts of the cladding, door mechanisms and panes, further deposits for workpieces and tools, the supply devices (including lines, hoses and pipes) for power, compressed air and polishing medium, the polishing medium return as well as measuring, maintenance and safety devices have been omitted;

[0043] FIG. 2 shows a perspective view of the device according to the invention—separately from the polishing machine according to FIG. 1 and there on the right—obliquely from above and front left as a separate polishing cell, wherein a tool carriage (linear axis X) for the tool spindles is disposed in a retracted setting and a work space, which is bounded downwardly by a trough, is closed by means of a bellows-like work space cover and a sliding door;

[0044] FIG. 3 shows a perspective view of the device according to FIG. 2 obliquely from above and rear right in which, by comparison with the illustration in FIG. 2, the parts (trough, sliding door, bellows-like work space covers) bounding the work space as well as the workpiece and tool spindles have been omitted, particularly for illustration of a linear drive for the pivot setting axes B, B′;

[0045] FIG. 4 shows a perspective view of the device according to FIG. 2 obliquely from above and front right, again with omission of the parts bounding the work space as well as the tool spindles and additionally the linear drive for the pivot setting axes B, B′, but with illustrated workpiece spindle (workpiece axis of rotation C), particularly for illustration of pivot yokes (pivot setting axes B, B′) for the tool spindles, which are arranged one behind the other, in the tool carriage (linear axis X);

[0046] FIG. 5 shows a perspective view of the device according to FIG. 2 obliquely from below and front right with illustration of all movement axes or movement possibilities (tool axes of rotation A, A′; pivot setting axes B, B′; workpiece axis of rotation C; linear axis X; adjusting axes Z, Z′) for the polishing process;

[0047] FIG. 6 shows a longitudinal sectional view of the device according to FIG. 2 with omission of components shown in FIG. 2, with the tool carriage (linear axis X) in the retracted setting, wherein for workpiece loading in the front region of the work space the sliding door is opened and the front bellows-like work space cover is retracted;

[0048] FIG. 7 shows a longitudinal sectional view, which corresponds with FIG. 6 with respect to the section plane, of the device according to FIG. 2, with the tool carriage (linear axis X) in an advanced setting for a tool change in which the tool spindles are pivoted forwardly (pivot setting axes B, B′) and additionally the tool is moved out at the rear tool spindle (adjusting axis Z′), again with opened sliding door in the front region of the work space, wherein, by comparison with FIG. 6, bellows provided at the tool spindles have been omitted for simplification of the illustration;

[0049] FIG. 8 shows a longitudinal section view of the front tool spindle, which is mounted in the front pivot yoke—illustrated partly broken away—of the device according to FIG. 2, with a polishing tool, at the tool mounting head of which is detachably mounted a polishing disc disposed in processing engagement with a surface to be processed, wherein the polishing tool is disposed in a lower setting moved out (adjusting axis Z) relative to the tool spindle and the associated bellows have been omitted for simplification of the illustration; and

[0050] FIG. 9 shows a half section of the front tool spindle with polishing tool according to FIG. 8 in demounted state, again without bellows between polishing tool and tool spindle, wherein the polishing tool together with the polishing disc is disposed in an upper setting which is moved in (adjusting axis Z) relative to the tool spindle and in which the tool mounting head of the polishing tool is detented at the workpiece spindle.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0051] A polishing machine as preferred case of use or use location of a device 10 for fine processing of optically effective surfaces cc, cx at workpieces such as, for example, spectacle lenses L (cf. FIG. 8) is denoted by 11 in FIG. 1. In the illustrated embodiment, arranged in a common machine frame 12 as polishing cells are—in correspondence with the number of spectacle lens L to be polished—three such devices 10, 10′, 10″ of respectively identical construction. As will be explained in more detail in the following with reference to FIGS. 2 to 7 on the basis of the device 10, which is on the right in FIG. 1, as representative for all three devices 10, 10′, 10″, the device 10 comprises a workpiece spindle 14 which projects into a work space 13 and by way of which a spectacle lens L to be polished, which is usually held by means of a blocking material M on a block piece S for mounting in the workpiece spindle 14 (see, again, FIG. 8), can be driven to rotate about a workpiece axis of rotation C. In addition, the device 10 comprises two tool spindles 16, 16′, which are associated with the workpiece spindle 17 and project oppositely into the work space 13 and on each of which a respective polishing tool 18, 18′ is mounted to be drivable for rotation about a tool axis of rotation A, A′ and to be axially adjustable along the tool axis of rotation A, A′ (adjusting axes Z, Z′). The tool spindles 16, 16′ are movable relative to the workpiece spindle 14 in common along a linear axis X extending substantially perpendicularly to the workpiece axis of rotation C and are pivotable about different pivot setting axes B, B′, which extend substantially perpendicularly to the workpiece axis of rotation C and substantially perpendicularly to the linear axis X. In that case, the tool spindles 16, 16′ are arranged one behind the other as seen in the direction of the linear axis X. This construction, which is significant for the device 10, can be best seen in FIG. 5.

[0052] Before the individual device 10 is described in detail, further details of its installation situation in the polishing machine 11 shall firstly be explained on the basis of FIG. 1. According to FIG. 1 the individual devices 10, 10′, 10″, which are operable independently of one another, are so arranged in compact manner adjacent to one another in modular form—and optionally to be separately exchangeable as a respective module—in the machine frame 12 that the respective linear axes X, X′, X″ extend substantially parallel to one another. This modular mode of construction allows, through identical subassemblies, production in common with corresponding batch number advantages and, moreover, permits flexible mounting of different manual or automatic variants.

[0053] Thus, in the embodiment illustrated in FIG. 1 a washing station 10, which is known per se, for washing the polished spectacle lenses L is mounted in the machine frame 12 adjacent to the device 10 on the right, and on the right adjacent to the washing station a transfer station 21, here provided with a conveyor belt 22, for deposit of prescription boxes 23, which are customary in spectacle lens production, for reception of spectacle lenses L which are to be polished and which are polished. The prescription boxes 23 can be moved back and forth in the polishing machine 11 by means of the conveyor belt 22 in correspondence with the movement arrow depicted on the conveyor belt 22 in FIG. 1.

[0054] In addition, the automated variant, which is shown here, of the polishing machine 11 has a portal handling system 24 by means of which the spectacle lenses L can be automatically transported between the stations 20, 21 and the devices 10, 10′, 10″ and positioned in the respective station 20, 21 or device 10, 10′, 10″. For that purpose, the portal handling system 24 comprises a suction unit 25, which is movable three-dimensionally, for holding a spectacle lens 11, which is to be polished, at the optically effective surface cc to be polished and a multi-finger gripper 26, which is movable three-dimensionally, for holding a polished spectacle lens L at the edge thereof. The mentioned possibilities of movement three-dimensionally are indicated in FIG. 1 by movement arrows x, y, z (horizontal or vertical linear movements) and b (tilting movement about a transverse axis parallel to the horizontal movement direction y).

[0055] More specifically, the portal handling system 24 comprises two x linear units 28, 28′ for producing the x movement, these units being arranged above the polishing machine 11 on either side of the machine frame 12. The x carriages 29, 29′ thereof each carry a respective pivot mount 30, 30′ which with the assistance of a pneumatic cylinder 31 enables tilting of a y linear unit 32, which is mounted on the pivot mounts 30, 30′ and forms the “portal”, for producing the y movement through approximately 20°. Through this measure, a z linear unit 34 mounted on a y carriage 33 of the y linear unit 32 can be tilted out of the vertical in order to be adapted to a workpiece spindle inclined setting, which cannot be seen in the drawings and which arises when the devices 10, 10′, 10″ are in the state of being mounted in the machine frame 12. The suction unit 25 and the multi-finger gripper 26 are mounted on the z linear unit 34 to be longitudinally displaceable and, in particular, in such a manner that they can be moved in opposite sense by means of a common drive, i.e. if the suction unit 25 is moved downwardly the multi-finger gripper 26 at the same time moves upwardly and vice versa.

[0056] To that extent it will be evident to the expert that a spectacle lens L to be polished can be lifted (z) by means of the suction unit 25 of the portal handling system 24 out of a prescription box 23 on the transfer station by a movement of the z linear unit 34 and then can be moved in three dimensions (b, x, y) and inserted (z) at the inclined workpiece spindle 14 of the desired device 10, 10′, 10″ for processing by polishing. After the processing by polishing, the spectacle lens L polished to finished state can be lifted (z) by means of the multi-finger gripper 26 out of the respective device 10, 10′, 10″, transported (b, x, y) to the washing station 20 and inserted (z) into this for removal of polishing medium residues by washing. The clean spectacle lens L can subsequently be lifted (z) by means of the multi-finger gripper 26 out of the washing station 20, moved (x, y) to the respective prescription box 23 on the transfer station 21 and deposited (z) therein. The spectacle lenses L can accordingly be transported in that way or in analogous manner by means of the portal handling system 24 as desired or necessary back and forth between the devices 10, 10′, 10″ and stations 20, 21.

[0057] For further description of the device 10 reference may now be made to FIGS. 2 to 7. According to, in particular, FIG. 4 the work space 13 of the device 10 is surrounded by a frame 36 which can be constructed as, for example, a welded construction of steel parts. Upwardly, the work space 13 can be covered by a bellows-like work space cover 38 and is closable at the front by a sliding door 39. In order to open the work space 13 for access from outside, the work space cover 38, which is suitably guided laterally, can be displaced or retracted by means of a pneumatic cylinder 40. In addition, a pneumatic cylinder 41 is provided for movement of the laterally guided sliding door 39 and is suitably pivotably connected between the sliding door 39 and the frame 36. Downwardly, the work space 13 is bounded by a trough 42, which is deep-drawn integrally from a plastics material and which is suitably fastened to the frame 36, with step-free wall surfaces and a receiving opening 43 for the workpiece spindle 41 (cf. FIGS. 6 and 7), through which trough the workpiece spindle 14 extends—suitably sealed at the circumference—from below so as to project into a lower region of the work space 13. In FIGS. 6 and 7 there can also be seen a drain opening 44 for the liquid polishing medium, which is disposed at the deepest point of the trough 42 in the state in which the device 10 is mounted in the machine frame 12 and tilted downwardly to the left by comparison with the illustration in FIGS. 6 and 7.

[0058] As can be seen in FIGS. 3 to 7, the frame 36 has a base plate 45 at which the workpiece spindle 14 is flange-mounted below the receiving opening 43 in the trough 42 from above (see, in particular, FIGS. 4, 6 and 7). At its end projecting into the work space 13 the workpiece spindle 14 has a collet chuck 46 which can be actuated by way of an actuating mechanism (not illustrated in more detail) so as to clamp a spectacle lens L, which is blocked on a block piece S, to the workpiece spindle 14 to be axially fixed and capable of rotational entrainment. A pneumatic cylinder, which is fastened below the base plate 45, for the said actuating mechanism is denoted by 47 (cf. FIGS. 5 to 7), by means of which the collet chuck 46 can be opened and closed in a manner known per se. As can be similarly seen in FIGS. 5 to 7, a rotary drive 48—in the illustrated embodiment a speed-controlled asynchronous three-phase motor—is flange-mounted from below on the base plate 45. The rotary drive 48—similarly below the base plate 45—is drivingly connected by means of a cogged belt drive with the roller-bearing-mounted spindle shaft of the workpiece spindle 14 so that the rotary drive 48 is capable of rotationally driving the workpiece spindle 14 at a predetermined rotational speed and with a predetermined direction of rotation (workpiece axis of rotation C).

[0059] A tool carriage 50 which is guided with respect to the frame 36 to be drivable along the linear axis X is provided above the workpiece spindle 14 for movement in common of the workpiece spindles 16, 16′. More precisely, provided for movement and positioning of the tool carriage 50, which is guided at two parallel guide rods 51, 52 connected with the frame 36 on opposite sides, is a rotary drive 53 which is mounted on the frame 36 in fixed location and which is drivingly connected with a ball screw drive 54. The latter has an axially fixed ball screw spindle 55, which is rotatably mounted at both ends and which is in engagement with a nut 56 connected with the tool carriage 50 to be secure against relative rotation. In that case, the tool carriage 50 according to FIGS. 3 to 5 is guided at one guide rod 51 merely by way of one axial bearing 57 (ball bush), whereas it is guided at the other guide rod 52 by way of two axial bearings 58 (ball bushes) which are axially spaced from one another in the direction of the guide rod 52 and of which merely the front axial bearing 58 can be seen in FIGS. 2 and 4. The rotary drive 53 for moving the tool carriage 50 is a servomotor, which is connected with the ball screw spindle 55 by way of, for example, a metal bellows coupling 59. The thus-constructed substantially horizontally extending linear axis X is subject to CNC positional closed loop control; however, for simplification of the illustration the associated travel measuring system is not shown.

[0060] As can be best seen in FIGS. 2, 4 and 5, the tool carriage 50 has a frame construction with an inner opening 60, which is substantially rectangular as seen in plan view, for receiving the two pivotable tool spindles 16, 16′. In that case one, i.e. front, tool spindle 16 is mounted on or in a front pivot yoke 61, which is pivotably connected with the tool carriage 50 on either side of the opening 60 to be capable of defined pivotation about one pivot setting axis B, and the other tool spindle 16′ is mounted on a rear pivot yoke 62, which is pivotably connected with the tool carriage 50 behind the front pivot yoke 61 to be capable of defined pivotation about the other pivot setting axis B′ again on either side of the opening 60. The corresponding bearing points present on either side of the opening 60 and at the carriage side or yoke side can be seen in FIGS. 4 and 5 at 63 and 64. From the schematic illustration in FIGS. 6 and 7 with respect thereto, it is evident with regard to the height of the bearing points 63, 64 that the two pivot setting axes B, B′ lie in a notional plane which extends along the linear axis X or parallel thereto.

[0061] A further linear drive 65 is provided for drive of the pivot yokes 61, 62, i.e. for defined pivotation in common of the two tool spindles 16, 16′ about the pivot setting axes B, B′ and is pivotably connected by one end thereof with the front pivot yoke 61 at a spacing from the corresponding pivot setting axis B and by the other end thereof with the tool carriage 50. More specifically, in the illustrated embodiment the linear drive 65 is a proprietary so-called “electrocylinder” with an actuating rod 66 which can be moved in and out by way of a rotary drive 67 and a transmission 68 in the case of corresponding energization of the rotary drive 67. If the rotary drive 67 is not energized, self-locking is present in the transmission 68, i.e. the actuating rod 66 remains in its respective initial setting in the case of non-excessive external forces; an integrated measuring system can feed back the respective position. This linear drive 65 is pivotably mounted at its end at the drive side on a mounting fork 69 mounted on the tool carriage 50, whereas at the other end of the linear drive 65 the actuating rod 66 pivotably engages a forked pivot arm 70 secured to the front pivot yoke 61 (see the screws in this region in FIGS. 2 to 4). For transmission of the pivot movement from the front pivot yoke 61 to the rear pivot yoke 62 the two pivot yokes 61, 62 are in drive connection by way of a coupling rod 71 which is spaced from the pivot setting axes B, B′, in particular above the latter by one end thereof at the front pivot yoke 61 (bearing point 72) and by the other end thereof at the rear pivot yoke 62 (bearing point 73).

[0062] In that respect it is apparent that in the case of the chain of pivotation formed as described above a defined axial movement out or movement in of the actuating rod 66 has the consequence that the pivot yokes 61, 62 are pivoted in defined manner about the pivot setting axes B, B′, whereby the tool spindles 16, 16′, which are arranged centrally in the respective pivot yoke 61 or 62, are pivoted while remaining in parallel orientation relative to one another.

[0063] Further details with respect to the tool spindles 16, 16′ can be inferred from FIGS. 8 and 9, which by way of example show, for the two identically constructed tool spindles 16, 16′ coupled to the respective pivot yoke 61, 61, the front tool spindle 16 (also) in section.

[0064] The tool spindle 16 comprises a spindle housing 74, by way of which the tool spindle 16 according to FIG. 8 is flange-mounted from below on the pivot yoke 61. The dot-dashed lines shown in FIG. 8 indicate a screw connection. The further components or subassemblies of the tool spindle 16 are rotatably mounted in the spindle housing 74 by way of a bearing arrangement of roller bearings comprising a lower fixed bearing 75 and an upper floating bearing 76, which are mounted in the spindle housing 74 at a spacing from one another by means of a spacer bush 77.

[0065] Each tool spindle 16, 16′ has a piston-cylinder arrangement 78, 78′ (also indicated in FIGS. 6 and 7) for axial adjustment (adjusting axes Z, Z′) of the respective polishing tool 18, 18′ along the associated tool axis of rotation A, A′. The piston-cylinder arrangement 78 has a piston 80 which is received in a cylinder housing 79 and which is connected, to be effective in terms of actuation, in coaxial arrangement with a spindle shaft 81 movable out of the spindle housing 74 in accordance with FIG. 8 (and FIG. 7). For movement of the spindle shaft 81 out of the spindle housing 74 the piston-cylinder arrangement 78 can be acted on pneumatically by way of a proprietary rotary transmission leadthrough 82 at the end of the cylinder housing 79 at the top in the figures. In that case, the piston-cylinder arrangement 78 together with the spindle shaft 81 is rotatable in the spindle housing 74 about the tool axis of rotation A, as already indicated.

[0066] According to FIGS. 8 and 9, the cylinder housing 79 is, in addition, of two-part construction with a housing upper part 83 and a housing lower part 84, which are screw-connected together centered relative to one another at 85. In that regard, received in the interior for lining the cylinder housing 79 is a guide sleeve 86 of mineral glass which is secured in the housing upper part 83 with the assistance of an O-ring 87 and in which the piston 80, which consists of a graphite material at its guide surface, is received to be longitudinally displaceable. “Glass cylinders” of that kind, which are very easy-running and substantially free of stick-slip, are commercially available from, for example, the company Airpot Corporation, Norwalk, Conn., United States. In order to avoid jamming, which can result from axial alignment errors in the (ideally) coaxially arranged components, the piston 80 of the piston-cylinder arrangement 78 is tension-resistantly and compression-resistantly connected with the spindle shaft 81 by way of a thin rod 88 of spring steel and, in particular, by way of the screw connections shown in FIGS. 8 and 9 at the top and bottom at the rod 88.

[0067] The housing lower part 84 of the cylinder housing 79 is rotatably supported by way of the floating bearing 76 in radial direction on the spindle housing 74 at the top in the figures. At the bottom in the figures, a labyrinth member 89 is flange-mounted on the housing lower part 84 by means of a screw connection 90 which in that case together with the housing lower part 84 axially clamps the inner ring of the fixed bearing 75 in place. The labyrinth member 89 forms, as the name itself indicates, together with the underside of the spindle housing 74 at 91 a sealing labyrinth with narrow gap dimensions and additionally has radially within the sealing labyrinth 91 an annular recess 92 for reception of a sealing ring 93, the sealing lip of which similarly sealably co-operates with the lower side of the spindle housing 74.

[0068] As FIG. 8 shows, the housing upper part 83 of the cylinder housing 79 passes through an opening 94 formed in the pivot yoke 61 and projects upwardly above this in FIG. 8. The housing upper part 83 of the cylinder housing 79 is there provided at the outer circumference with a toothing 95 (cf. FIG. 9) for engagement by a cogged belt 96. The cogged belt 96 is drivable by way of a motor 97—which is flange-mounted from above on the pivot yoke 61 and is similarly of identical construction for each pivot yoke 61, 62—with a belt pulley 98 so as to rotate the piston-cylinder arrangement 78 and thus the spindle shaft 81 in the spindle housing 74 controllably in rotational speed and rotational direction about the tool axis of rotation A.

[0069] In addition, provided for torque transmission from the thus-rotating drivable cylinder housing 79 of the piston-cylinder arrangement 78 to the spindle shaft 81 is a splined shaft guide 99 with guide grooves 100, which are formed in the spindle shaft 81, and a flange nut 102, which is in engagement therewith by way of an axial bearing element 101—since it is known per se, it is indicated in FIGS. 8 and 9 merely by a thick line—and which is received in the labyrinth member 89 and flange-mounted thereon by means of a screw connection 103, so that the flange nut 102 is connected with the cylinder housing 79 to be secure against relative rotation. Splined shaft guides of that kind are commercially available from, for example, the company Nippon Bearing Co Ltd, Ojiya-City, Japan.

[0070] To that extent it is evident that the spindle shafts 81, 81′ of the tool spindles 16, 16′ are drivable—controllably in rotational speed and rotational direction—at a given time independently of one another for rotation about the tool axes of rotation A, A′ and/or adjustable independently of one another along the tool axes of rotation A, A′, in a given case also with very fine sensitivity (adjusting axes Z, Z′).

[0071] Details with respect to the polishing tool 18, which is currently preferred for use in this device 10, can similarly be inferred from FIGS. 8 and 9. According to that, the polishing tool 18 has a tool mounting head 104 with a mounting plate 105 which is secured to the spindle shaft 81 of the tool spindle 16 to be capable of axial and rotational entrainment and at the same time to be detachable.

[0072] A polishing disc 106 is exchangeably mounted on the tool mounting head 104, for which purpose a base body 107 of the polishing disc 106 and the tool mounting head 104, more precisely the mounting plate 105 thereof, are provided with complementary structures 108 for axial detenting and rotational entrainment of the polishing disc 106 by the tool mounting head 104. This interface, which is formed by the complementary structures 108, between polishing disc 106 and tool mounting head 104 is the subject of document EP 2 464 493 B1, to which, for avoidance of repetitions, express reference may be made at this point with regard to construction and function of the interface.

[0073] On the side of the mounting plate 105 remote from the polishing disc 106 the tool mounting head 104 has a ball joint 109 with a ball head 111 which is received in a ball socket 110 and which is constructed at a ball pin 112 securable to the spindle shaft 81 of the tool spindle 16, more precisely able to be screwed in at the end thereof. On the other hand, the ball socket 110 is formed in the mounting plate 105 with which the polishing disc 106 is detentable. In the illustrated embodiment the ball head 111 has a receiving bore 113 for a transverse pin 114, which extends through the ball head 111 by radiused ends and engages on either side of the bore head 111 in associated recesses 115 in the ball socket 110 so as to connect the mounting plate 105 in the manner of a universal joint with the ball head 111 and thus with the spindle shaft 81 of the tool spindle 16 to be capable of rotational entrainment.

[0074] In addition, a circularly annular support flange 116 is introduced between the ball pin 112 and the free end of the spindle shaft 81 and is secured to the spindle shaft 81 by means of the ball pin 112. A resilient annular element 117 consisting of, for example, a suitable foam material rests on the support flange 116, by way of which annular element the mounting plate 105 of the tool mounting head 104 can be resiliently supported on the support flange 116 at the ball pin side in such a manner that the polishing disc 106 detented with the mounting plate 104 seeks to self-align by its center axis with the ball pin 112 and thus the spindle shaft 81 of the tool spindle 16.

[0075] In addition, it can be seen in FIGS. 8 and 9 that the tool mounting head 104 in an axially retracted setting of the spindle shaft 81 (cf. FIG. 9) can be detented with the labyrinth member 89—as a part connected with the cylinder housing 79 to be secure against relative rotation—by means of a detent device 118. The detent device 118 has a plurality of spring projections 119, which are distributed around the circumference of the tool mounting head 104 and protrude along the tool axis of rotation A and which are in mechanically positive engagement with lugs 120 in an annular groove 121 formed at the labyrinth member 89. The polishing tool 18 can thus be mounted without force by detenting in a retracted setting at the tool spindle 16. For recognition of the moved-up position of the polishing tool 18—and thus a tool loading position of the tool spindle 16—an annular magnet RM is glued in place in the piston 80 of the piston-cylinder arrangement 78 and co-operates with a magnet sensor MS (see FIGS. 2, 6 and 7) in the vicinity of the rotary transmission leadthrough 82.

[0076] An intermediate layer 122, which is softer by comparison with the base body 107 and on which a polishing medium carrier 123 rests, of a resilient material is secured to the base body 107 of the polishing disc 106 illustrated here, the polishing medium carrier 123 forming the actual outer processing surface 124 of the polishing disc 106. This design of the polishing disc 106 is to that extent special, since the intermediate layer 122 has at least two regions of different hardness which are arranged one behind the other in the direction of the center axis of the polishing disc 106, wherein the region of the intermediate layer 122 adjoining the base body 107 is softer than the region of the intermediate layer 122 on which the polishing medium carrier 123 rests. More precisely, the two regions of the intermediate layer 122 are here formed by mutually different foam material layers 125, 126 of respectively constant thickness as seen along the center axis of the polishing disc 106, namely a softer foam material layer 125 on the base body 107, more precisely the spherical end surface 127 thereof, and a harder foam material layer 126 under the polishing medium carrier 123. In that case, the individual components (107, 125, 126, 123) of the polishing disc 106 are glued together. This polishing disc 106, which is universally usable for a wide range of workpiece curvatures, in particular the actual construction and dimensioning thereof, is the subject of parallel, i.e. filed on the same application date, German Patent Application DE 10 2014 XXX XXX.X, to which at this point express reference may be made with regard thereto for avoidance of repetitions.

[0077] Other polishing tools or polishing discs can obviously also be used with the device 10 in correspondence with the respective polishing requirements. Thus, for example, it would be possible to use tools according to the document U.S. Pat. No. 7,559,829 B2 without an individual rotary drive. In this case, mounting bore and transverse pin would be just as redundant in the ball head of a somewhat longer ball pin as the support flange and the resilient annular element of the polishing tool illustrated here. Instead, a flange, which is similar, but somewhat larger in diameter, with an outer radial groove for receiving a bellows would be used. Since the device 10 has the two spindles 16, 16′ arranged one behind the other, a “mixed drive” would also be possible, with an active rotationally driven polishing tool 18, as shown in the figures, at one tool spindle 16 and a merely “passive” rotationally entrained polishing tool according to, for example, document U.S. Pat. No. 7,559,829 B2 at the other tool spindle 16′.

[0078] The different polishing processes able to be performed by the afore-described kinematics of the device 10—in which moreover a liquid polishing medium is supplied to the point of action between tool and workpiece by way of polishing medium nozzles 128 provided at the workpiece spindle 14 (see FIGS. 4 to 7, in which one such nozzle is illustrated by way of example for a plurality of nozzles distributed at the circumference of the workpiece spindle 14)—are well-known to the expert and therefore shall not be described in more detail at this point.

[0079] A device for fine processing of optically effective surfaces of, in particular, spectacle lenses as workpieces comprises a workpiece spindle, which projects into a work space and by way of which a workpiece to be polished is rotationally drivable about a workpiece axis of rotation (C), and two tool spindles associated with the workpiece spindle and projecting oppositely into the work space. A respective polishing tool is mounted on each of the tool spindles to be drivable for rotation about a tool axis of rotation (A, A′) and axially adjustable (adjusting axis Z, Z′) along the tool axis of rotation. In addition, the tool spindles are movable in common relative to the workpiece spindle along a linear axis (X) extending substantially perpendicularly to the workpiece axis of rotation and pivotable about different pivot setting axes (B, B′) extending substantially perpendicularly to the workpiece axis of rotation and substantially perpendicularly to the linear axis. In that case, the tool spindles are arranged one behind the other as seen in the direction of the linear axis. As a consequence of such an arrangement the device is of very compact construction and is widely usable for different polishing processes and polishing strategies.

REFERENCE NUMERAL LIST

[0080] 10, 10′, 10″ device [0081] 11 polishing machine [0082] 12 machine frame [0083] 13 work space [0084] 14 workpiece spindle [0085] 16, 16′ tool spindles [0086] 18, 18′ polishing tool [0087] 20 washing station [0088] 21 transfer station [0089] 22 conveyor belt [0090] 23 prescription box [0091] 24 portal handling system [0092] 25 suction unit [0093] 26 multi-finger gripper [0094] 28, 28′ x linear units [0095] 29, 29′ x carriages [0096] 30, 30′ pivot mount [0097] 31 pneumatic cylinder [0098] 32 y linear unit [0099] 33 y carriage [0100] 34 z linear unit [0101] 36, 36′, 36″ frame [0102] 38, 38′, 38″ work space cover [0103] 39, 39′, 39″ sliding door [0104] 40, 40′, 40″ pneumatic cylinder [0105] 41, 41′, 41″ pneumatic cylinder [0106] 42 trough [0107] 43 receiving opening [0108] 44 drain opening [0109] 45 base plate [0110] 46 collet chuck [0111] 47 pneumatic cylinder [0112] 48, 48′, 48″ rotary drive [0113] 49 cogged belt drive [0114] 50 tool carriage [0115] 51 guide rod [0116] 52 guide rod [0117] 53 rotary drive [0118] 54 ball screw drive [0119] 55 ball screw spindle [0120] 56 nut [0121] 57 axial bearing [0122] 58 axial bearing [0123] 59 metal bellows coupling [0124] 60 opening [0125] 61 front pivot yoke [0126] 62 rear pivot yoke [0127] 63 bearing point at carriage side [0128] 64 bearing point at yoke side [0129] 65, 65′, 65″ linear drive [0130] 66 actuating rod [0131] 67 rotary drive [0132] 68 transmission [0133] 69 mounting fork [0134] 70 pivot arm [0135] 71 coupling rod [0136] 72 bearing point [0137] 73 bearing point [0138] 74 spindle housing [0139] 75 fixed bearing [0140] 76 floating bearing [0141] 77 spacer bush [0142] 78, 78′ piston-cylinder arrangement [0143] 79 cylinder housing [0144] 80 piston [0145] 81, 81′ spindle shaft [0146] 82, 82′ rotary transmission leadthrough [0147] 83 housing upper part [0148] 84 housing lower part [0149] 85 screw connection [0150] 86 guide sleeve [0151] 87 O-ring [0152] 88 rod [0153] 89 labyrinth member [0154] 90 screw connection [0155] 91 sealing labyrinth [0156] 92 annular recess [0157] 93 sealing ring [0158] 94 opening [0159] 95 toothing [0160] 96 cogged belt [0161] 97 motor [0162] 98 belt pulley [0163] 99 splined shaft guide [0164] 100 guide groove [0165] 101 axial bearing element [0166] 102 flange nut [0167] 103 screw connection [0168] 104 tool mounting head [0169] 105 mounting plate [0170] 106 polishing disc [0171] 107 base body [0172] 108 complementary structures [0173] 109 ball joint [0174] 110 ball socket [0175] 111 ball head [0176] 112 ball pin [0177] 113 receiving bore [0178] 114 transverse pin [0179] 115 recess [0180] 116 support flange [0181] 117 resilient annular element [0182] 118 detent device [0183] 119 spring projection [0184] 120 lug [0185] 121 annular groove [0186] 122 intermediate layer [0187] 123 polishing medium carrier [0188] 124 processing surface [0189] 125 softer foam material layer [0190] 126 harder foam material layer [0191] 127 end surface [0192] 128 polishing medium nozzle [0193] A rotational axis of front polishing tool (open loop controlled in rotational speed) [0194] A′ rotational axis of rear polishing tool (open loop controlled in rotational speed) [0195] b tilting movement of portal handling system [0196] B pivot setting axis of front polishing tool [0197] B′ pivot setting axis of rear polishing tool [0198] C workpiece rotational axis (open loop controlled in rotational speed) [0199] cc second optically effective surface [0200] cx first optically effective surface [0201] L spectacle lens [0202] M blocking material [0203] MS magnet sensor [0204] RM annular magnet [0205] S block piece [0206] x linear movement of portal handling system [0207] X linear axis of tool carriage (closed loop controlled in position) [0208] y linear movement of portal handling system [0209] z linear movement of portal handling system [0210] Z adjusting axis of front polishing tool (uncontrolled) [0211] Z′ adjusting axis of rear polishing tool (uncontrolled)