EP0143468B1 - Edge grinding method and apparatus - Google Patents

Edge grinding method and apparatus Download PDF

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Publication number
EP0143468B1
EP0143468B1 EP19840114476 EP84114476A EP0143468B1 EP 0143468 B1 EP0143468 B1 EP 0143468B1 EP 19840114476 EP19840114476 EP 19840114476 EP 84114476 A EP84114476 A EP 84114476A EP 0143468 B1 EP0143468 B1 EP 0143468B1
Authority
EP
European Patent Office
Prior art keywords
lens
measuring
frame
measuring means
radius
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19840114476
Other languages
German (de)
French (fr)
Other versions
EP0143468A2 (en
EP0143468A3 (en
Inventor
Atsushi C/O Tokyo Kogaku Kikai Hara
Nobuhiro C/O Tokyo Kogaku Kikai Isokawa
Yasuo C/O Tokyo Kogaku Kikai Suzuki
Yoshiyuki C/O Tokyo Kogaku Kikai Hatano
Hiroaki C/O Tokyo Kogaku Kikai Oogushi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Topcon Corp
Original Assignee
Tokyo Kogaku Kikai KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP58225197A external-priority patent/JPH0659611B2/en
Priority claimed from JP58225198A external-priority patent/JPH0659612B2/en
Application filed by Tokyo Kogaku Kikai KK filed Critical Tokyo Kogaku Kikai KK
Publication of EP0143468A2 publication Critical patent/EP0143468A2/en
Publication of EP0143468A3 publication Critical patent/EP0143468A3/en
Application granted granted Critical
Publication of EP0143468B1 publication Critical patent/EP0143468B1/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • B24B9/02Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
    • B24B9/06Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
    • B24B9/08Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass
    • B24B9/14Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass of optical work, e.g. lenses, prisms
    • B24B9/144Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass of optical work, e.g. lenses, prisms the spectacles being used as a template

Definitions

  • the present invention relates to a method and apparatus for grinding a spectacle lens so that it fits to a spectacle frame according to the first part of independent claims 1 and 4.
  • a spectacle lens is ground at the edge portion before it is fitted to a spectacle frame so that its peripheral configuration conforms to the shape of the frame.
  • a template is usually prepared modeling the spectacle frame and the lens edge is ground copying the template.
  • the lens is ground directly copying the spectacle frame.
  • this object can be accomplished by a method as described in claim 1 and by an apparatus as described in claim 4.
  • a grinding section in accordance with one embodiment of the lens edging apparatus of the present invention.
  • a grinding wheel 3 comprising a roughing wheel 3a, a beveling wheel 3b having a large V-shaped groove in its periphery, and a cylindric precision grinding wheel 3c, and the wheel 3 is secured on a shaft 5 having a pulley 4.
  • the pulley 4 is connected with a grinding motor 6 through a belt 7 so that the wheel 3 is rotated by the motor 6.
  • bearing members 10, 11 which are adapted to rotationally, axially-movably hold a carriage shaft 12.
  • One end of the carriage shaft 12 is rotationally mounted on a bearing member 21a provided on a later mentioned transfer station 20.
  • a work holding shaft 18 comprising a pair of shafts 18a, 18b for holding a lens LE to be edged.
  • the shaft 18a has an operation handle 19 at its end, and by rotation of the handle 19 the shaft 18a is slided along its axis so that the shafts 18a, 18b supports the lens LE between them.
  • a lens measuring means 30 mentioned later an arm portion 31 of which is mounted on the shaft 12 so as to swing on an axis in common with the one of the carriage 13.
  • a base plate 21 of the station 20 has a pair of wheels 22 which are adapted to roll on rails 23 secured on the housing 1 so that the station 20 is possible to move along the rails 23.
  • the station 20 has a female screw 24 to be engaged with a' transfer male screw 41, which is rotated by a motor 40 so that the station 20 is moved in both directions as shown by an arrow 25.
  • the shaft 12, as mentioned above, is rotationally mounted on the member 21a, and therefore the carriage 13 horizontally moves simultaneously with the station 20.
  • the base plate 21 has two vertical shafts 26, 26' parallel to each other, which movable mount a stopping member 27.
  • the stopping member 27 has a female screw 28 to be engaged with a transfer male screw 43, which is rotated by a Z-axis motor 40 so that the stopping member 27 is moved upwards or downwards.
  • the carriage 13 also has an arm portion 16a which mounts a rotation wheel 16b at its end, and the rotation wheel 16b is placed on an upper surface of the stopping member 27 so that the carriage 13 is possible to swing in response to a vertical motion of the stopping member.
  • FIG. 2A there is shown means for digitally measuring a configuration of the eyeglass frame or a lens pattern previously made in accordance with the eyeglass frame.
  • the shaft 18b is supported by a bearing member 50 formed on the carriage 13.
  • the shaft 18b mounts a detecting arm 51 at its end 18c, and a long side frame 52 of the detecting arm 51 is mounted on an end portion 18c of the shaft 18b at right angle to a rotation axis of the shaft 18b.
  • a detector 54 is provided on another long side frame 53 to be moved thereon and biased to the end portion of the frame 53 by a pressure spring 59 coiled around the frame 53.
  • On short side frames 55, 56 of the arm 51 there are rotationally provided with pulleys 57, 58, respectively.
  • the shaft 18b rotationally supports a pulley 60 which is united with a code disc 62 of an encoder 61.
  • a detecting head 62a of the encoder 61 is secured to an outside of the arm 16.
  • a first wire 80 is wound around the pulley 60 and secured to the detector 54 through the pulley 57 and the side of the pulley 60 at their ends, respectively.
  • a second wire 81 is wound around the pulley 60 in an opposite direction to the first wire 80 and secured to the detector 54 through the pulley 60 and the side of the pulley 60 at their ends, respectively, thereby, displacement of detector 54 on the frame 53 may be detected as rotation angle of the pulley 60 or the disc 62.
  • the detector 54 as shown in Figure 3, comprises a sliding seat 541 movably mounted on the frame 53, a sliding rotationed shaft 543 rotationally supported by the seat 541, and a detecting feeler 542 secured to the shaft 543.
  • the detecting feeler 542 has a lens pattern feeler 544 and an eyeglass frame contacting wheel 546.
  • the feeler 542 is a portion of the shaft 543, which is portionally cut out so as to form a semicircular cross section.
  • the wheel 546 is rotationally provided on an end of a U-shaped arm member 545 which is mounted on the shaft 543.
  • a contacting surface 544a of the feeler 544 and a contacting periphery 546a of the wheel 546 are located so as to include an axis 0, of the shaft 543.
  • a pin 547 is inserted so as to be parallel to the surface 544a, and the pin 547 engages with a stopping member 548 fixed on the frame 52 on its side surface when the detector 54 is on the first position.
  • the shafts 18, 18a have sprocket wheels 74, 75, resectively. Chains 76, 77 link the sprockets 72, 74, to the sprockets 73, 75, respectively, so that the shafts 18, 18a are rotated by the motor 70.
  • an eyeglass frame holding means 90 a station 91 which is located parallel to longitudinal direction of the arm member 16 at the time when the carriage 13 is on the first position.
  • the station 91 has a pair of rails 92, 93 parallel to the longitudinal direction of the arm member 16, which movably support eyeglass frame supporting members 94, 95.
  • the supporting members 94, 95 are always biased by a spring 96 toward each other.
  • the supporting member 95 has a screw portion at its leg portion 95a, which engages with a transfer screw 97a provided on a shaft of a Y-axis motor 97.
  • the supporting members 94, 95 have fitting member 94c, 95c at upper portions of arms 94b, 95b in order to fit an eyeglass frame holding member 100.
  • the holding member as shown in Figure 2B, has a base plate 101 providing a circle opening 102 at its center, eyeglass frame holding arms 103,104 provided on the plate 101 being opposite to each other, and a pressure member 105 for pressing an eyeglass frame 200.
  • the arms 103, 104 hold upper and lower limbs of the eyeglass frame 200 and the pressure member 105 presses the lens frame 200, so that the eyeglass frame 200 is secured on the opening 102 of the member 100.
  • a fore end 105a and a rear end 105b of the pressure member 105 are projected from concavities 103a, 104a of the arms 103, 104, thereby a fore end 101a a and a rear end 101 b (not shown in Figures) of the plate 101 are on the same plane with the ends 105a, 105b, respectively.
  • the member 100 holding the eyeglass frame 200 is supported by the members 94c, 95c.
  • the base plate 101, the pressure member 105 and the concavities 103a, 104a are designed so that an upper edge of the rear and 106b and a lower edge of the rear end 101 b are positioned at the same distance d from a center axis of a V-shaped groove of the lower limb.
  • the supporting members 94c, 95c have V-shaped grooves 94d, 95d, respectively.
  • a template holding member 110 is used in the case of that a lens template 210 is supported by the supporting members 94, 95.
  • the member 110 comprises a holding frame 111, pole members 112, 113 secured on an opposite ends of the holding frame 111, a template holding pole 111 a fixed to the frame 111 at its center, and pins 114, 115, 116 projected from the template holding pole 111 a at its end.
  • the pattern 210 has three holes to be engaged with the pins 114, 115, 116.
  • the eyeglass holding member 100 is held by the supporting members 94, 95, and the carriage 13 is moved by rotation of the Z-axis motor 40 in a direction of an arrow A (shown in Figure 1) by the predetermined displacement.
  • the eyeglass handling member 100 is moved along the rails 92, 93 by the predetermined displacement and the eyeglass frame 200 is moved to the first set position so that the center 201 b of the V-shaped groove of the lower limb is in contact with the contacting wheel 546 in the same plane, and the rotation axis 0 1 of the detecting arm 51 is located in the eyeglass frame 200.
  • a radius vector ⁇ n of the detecting arm 51 being at the rotation angle ⁇ n includes rotation of the detecting arm 51, and therefore
  • the values ( ⁇ n , ⁇ n ) are those in the case where the rotation center 0 2 of the detecting arm 51 is located at any position in the eyeglass frame 200 and not in the case where the rotation center 0 2 is located at a geometric center of the eyeglass frame 200.
  • FIGs 6A and 6B there is shown a method to invert the former into the latter. Locating the carriage 13 at the first position, a Y-axis is taken to be line connecting between the rotation center 0 2 and a swing center 0 of the carriage 13, and a X-axis is taken to be one crossing the Y-axis at a right angle.
  • the eyeglass frame data ( ⁇ n , ⁇ n ) under rectangular coordinate are converted into those (x n , y n ) under polar coordinate through the following transforming equations (3);
  • the operation mentioned above leads to make the rotation center of the detecting arm 51 coincident with the geometric center 0 3 of the eyeglass frame 200. Subsequently, the detecting arm 51 is rotated by an angle (3 in order to shift a position of the origin. In the present condition, the detecting arm 51 is rotated along the whole periphery of the lens frame 200 again, so that the digital configuration values ( ⁇ n , ⁇ n ) of the eyeglass frame 200 are obtained and memorized.
  • FIG 7 there is shown a method for measuring the lens template which is used instead of the eyeglass frame.
  • elements corresponding to those shown in Figure 5 are with the same reference numerals and explanations thereof are omitted.
  • the feeler 544 is moved to be in contact with a periphery of the lens template 210 and the detecting arm 51 is rotated.
  • the detecting arm 51 is shifted from the origin 0 by the predetermined distance to locate the rotation axis O2 thereof in the lens pattern 210.
  • a radius vector t ⁇ n is represented as follows: while, in case where the detecting arm 51 is positioned at the first standard position, a radius vector po is represented as follows;
  • a contact point 546a between the groove of the eyeglass frame 200 and the contacting wheel 546 and the contacting surface 544a are adapted to be located on the axis 0, of the shaft 543, at the measuring time the contacting wheel 546 and the feeler 544 supported by the U-shaped arm member 545 are pressed against the groove of the eyeglass or the lens template, and the member 545 is turned to a line perpendicular to a contact surface between the wheel 546 and the groove or the feeler 544 and the lens pattern. Consequently, the measurement mentioned above is always carried out with precision.
  • FIG 8 there is shown an edging means for edging pre-edged lens LE in accordance with the values obtained by the above mentioned measuring means and the operation thereof.
  • the pre-edged lens is mounted by the shafts 18, 18a (refer to Figure 1), and the motor 6 is energized, so that the pre-edged lens falls on the wheel 3 by its gravity in order to be edged thereby.
  • Displacement of the carriage 13 is measured by the linear encoder 610, which comprises a scale 611 provided on a side of the arm portion 31 of the lens measuring means 30 so as to rotate it about a pivotal point P, and a detector head 612 pivoted on the side of the carriage 13.
  • a rotation angle y of the carriage 13 in response to displacement from the center 0 3 to the center 0 2 is the same as the rotation angle y' of the detector head 612.
  • the rotation angle y' being equal to one of the carriage 13 is read out on the scale 611.
  • a distance between e, and 1 2 is substantially equal to a length c between e' 1 and e 2 .
  • the present embodiment is designed so that, suppose that a radius is equal to the length between the shaft 12 and the point P and an included angle is equal to a rotation angle of the carriage 13, a hypotenuse P in response to an arc 613 becomes equal to the length C. Thereby, the value read by the encoder 610 becomes equal to the hypotenuse P in the case where the carriage 13 is rotated by angle y, and the length Y n becomes twice as much as the above value.
  • FIG. 9 there is shown the lens measuring means 30 disclosed in Figure 1.
  • Shafts 302, 303 are fixed on a base 301 normally projected from the arm portion 31 and pivot link arms 304, 305 at their ends, respectively.
  • Arm members 309, 310 are mounted on a link bar 306 at its ends and pivoted by the link arm 304, 305 at their other ends through shaft 307, 308, respectively.
  • the link arm 304, 305 the link bar 306 and the base 301 form a link motion.
  • the arm members 309, 310 have shifts 311, 312 lying parallel to the link bar 306 through deformed ellipitical frames 317, 318. Other deformed elliptical frames 313, 314 pivot the shafts 311, 312 at their ends, respectively.
  • a U-shaped arm portion 315a of a shaft member 315 is movably engaged with the shaft 311 at its middle portion and the shaft member 315 is movably engaged with a bearing portion 316a of a moving member 316.
  • the moving member 316 has a pin 319 on its upper surface which is movably engaged with a slit 320a of an arm member 320.
  • the arm member 320 is pivoted by a shaft 321 projected from the base 301 at its end.
  • a U-shaped arm portion 322a of a shaft member 322 is movably engaged with the shaft 312 at its middle portion and the shaft member 322 is movably engaged with a bearing portion 323a of a moving member 323.
  • the moving member 323 has a pin 319 on its upper surface which is movably engaged with a slit 325a of an arm member 325.
  • the arm member 325 is pivoted by a shaft 326 projected from the base 301 at its end.
  • the base 301 mounts an arm motor 330 a rotation shaft of which is provided with an arm plate 331.
  • the arm plate 331 has rotary wheels 332,333 at its opposite ends, which are pressed to each side of the arm members 320, 325.
  • the arm member 320 mounts a detecting head 335 of an encoder 334 at its middle portion, and a scale 337 of the encoder 334 passes through the detecting head 335.
  • the base 301 pivots a scale 337 at its end.
  • a detecting head 339 is mounted on the arm member 325 at its middle portion, and a scale 340 of the encoder 334 passes through the detecting head 339.
  • Two rail members 341, 342 passing through frames 313, 314 are supported by frames 317, 318 parallel to the link bar 306 so as to support the frames 313, 314.
  • the frame 313 is engaged with a cylindric member 345 at its end into which a cylindric member 343 is rotationary inserted on a common axis thereof.
  • the U-shaped arm portion 315a of the shaft member 315 is movably engaged with a groove 343a formed on the outer periphery of the cylindric member 343.
  • the frame 314 is engaged with a cylindric member 345 at its end into which a cylindric member 346 is rotationally inserted on a common axis thereof.
  • the U-shaped arm portion 322a of the shaft member 322 is movably engaged with a groove 346a formed on an outer periphery of the cylindric member 343.
  • a ring 347 having a bevel 347a and a ring 348 having a bevel 348 are movably mounted on the cylindric member 345.
  • the cylindric member 345 has a groove 345a parallel to an axis thereof, and a pin 349 connects the ring 347 with the cylindric member 343 and a pin 350 connects the ring 348 with the cylindric member 346.
  • FIGs 14 through 18 there is shown operations of the lens measuring means mentioned above.
  • the carriage 13 is returned to the first position so that the edged lens LE is brought to the predetermined position.
  • an eccentric cam 360 is rotated by a driving means (not shown in Figure) so that the lens measuring means is turned about the shaft 12 to make the cylindric member 345 contact with thie periphery of the edged lens LE.
  • the rotary work holder 18 is stepwise rotated by the predetermined angle in the same manner as edging the lens, and the radius vector p' of the edged lens is measured at each stepped angle.
  • the radius vector is read out by the detecting head 612 moving on the scale 611 in response to swing of the carriage 13, while on measuring the radius vector of the edged lens the radius vector, as shown Figure 14, is read out on the scale 611 moved in response to the swing of the arm portion 31 by the detecting head 612 mounted on the fixed carriage 13.
  • FIG. 15 through 17 there is shown measuring of curvature and peripheral thickness of lens by the lens measuring means 30.
  • the motor 330 is energized not to make the arm plate 331 press the arm members 320, 325, so that the cylindric members 343, 346 are moved toward each other by the spring 353.
  • the periphery of the lens LE is got between the rings 347, 346 linked with the cylindric members 343, 346.
  • the cylindric members 343, 346 make the arm members 320, 325 swing, and the rotation angle of the arm members 320, 325 or the displacement of the rings 347, 348 are measured by the encoders 334, 338.
  • the lens LE is stepwise rotated, and the displacement of the rings 347, 348 are measured at each rotation angle of the lens LE.
  • f Z A and f Z S mean readings measured through the ring 347 at position A and B
  • respectivey, p' A and p' B mean radius vectors at the position A and B, respectively
  • R f means curvature radius of a front surface having a curvature center f Z o on the rotation axis of the lens LE
  • n means a refractive index of lens or usually 1.523
  • C f means a curve value of the front surface of the lens.
  • the curvature radius R f is calculated from the equation (8) and the curve value C f is calculated from the equation (9) using the above radius R f .
  • C r means a curve value of the rear surface
  • the peripheral thicknesses ⁇ A, ⁇ B of the lens LE is calculated from the following equation
  • the control circuit includes an oeration and control circuit 1500 comprising a micro-processor for carrying out various operations and program control, a motor control circuit 1200, a counting circuit 1100 for counting output signals of the encoders 61, 334, 339 and 610, a frame configuration memory 1300 for memorizing value signals of the eyeglass frame and the lens pattern produced by the circuit 1500, a bevel edge input and output system 1400 having an input keyboard 1401, a liquid crystal display device 1402 and an interface 1403, and a bevel edge data memory 1600.
  • a micro-processor for carrying out various operations and program control
  • a motor control circuit 1200 for carrying out various operations and program control
  • a counting circuit 1100 for counting output signals of the encoders 61, 334, 339 and 610
  • a frame configuration memory 1300 for memorizing value signals of the eyeglass frame and the lens pattern produced by the circuit 1500
  • a bevel edge input and output system 1400 having an input keyboard 1401, a liquid crystal display device 1402 and an interface 1403, and
  • the motor control circuit 1200 is adapted to control the Y-axis motor 97, the motor 70 for rotating the lens shaft 18, the motor 1208 for rotating the lens measuring means 30, the Z-axis motor 40 for moving the carriage 13 in the Z-axis, the X-axis motor 42 for moving the stopping member 27 in the X-axis and the grinding motor 6.
  • the encoder 334 measures the position of the front periphery of the edged lens LE or the value f Z a at the rotation angle ⁇ A as shown in Figure 17.
  • the outputs of the encoder 334 are counted by the counting circuit 1100 and the counted value f Z a is fed to the circuit 1500.
  • the encoder 334 measures the position of the rear periphery of the edged lens LE or the value ,Z a at the rotation angle p A .
  • the outputs of the encoder 334 are counted by the counting circuit 1100 and the counted value ,Z a is fed to the circuit 1500.
  • Step 3-4 The motor 1208 is energized by the motor control circuit 1200 to make the lens measuring means 30 return to the original position.
  • the circuit 1500 controls the circuit 1200 in such a way that, while the counting circuit 1100 is counting the output of the encoder 610, the Z-axis motor 40 and the X-axis motor 42 are energized until the beveling wheel 3b performs the curve value and the shift of the bevel edge at the radius vector ( ⁇ ' n , ⁇ n ) memorized by the memory 1600. The operation is repeated at every radius vector angle ⁇ n .
  • Step 5-4 After finishing the beveling at every radius vector angle ⁇ n , the X-axis motor 42 is energized to return the carriage 13 to the first position and the rotation of the grinding motor 6 is stopped.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)

Description

  • The present invention relates to a method and apparatus for grinding a spectacle lens so that it fits to a spectacle frame according to the first part of independent claims 1 and 4.
  • A method and an apparatus of that kind is known from EP-A-92 364.
  • Conventionally, a spectacle lens is ground at the edge portion before it is fitted to a spectacle frame so that its peripheral configuration conforms to the shape of the frame. For the purpose, a template is usually prepared modeling the spectacle frame and the lens edge is ground copying the template. In an alternative procedure, the lens is ground directly copying the spectacle frame. In such known procedures, there is no means for measuring the accuracy of the grinding operation, so that the only way of confirming that the lens has been edged to a satisfactory extent is to try to fit the lens to the spectacle frame. Further, when it is found that the edging work is incomplete, it has been very difficult to determine the portion and the amount of additional grinding required for completing the edging work. Thus, in the conventional methods, skills and experiences of workmen have been required and it has been difficult to maintain the accuracy of the edging. Particularly, in the method wherein the edging work is performed copying the spectacle frame directly, it is required to remove the spectacle frame from the grinding machine each time when the result of the grinding work is to be inspected. When it is found that a further grinding is necessary, the spectacle frame has to be mounted on the machine but it is very difficult to locate the spectacle frame exactly at the same position where it was located before it was removed. Therefore, there is a high possibility of working errors being produced due to errors in locating the spectacle frame.
  • It is therefore the object of the present invention to improve a spectacle lens grinding method and apparatus.
  • According to the present invention, this object can be accomplished by a method as described in claim 1 and by an apparatus as described in claim 4.
  • Advantageous improvements of the method and the apparatus according to the invention are described in the subclaims.
  • Brief description of the drawings
    • Figure 1 is a perspective view showing the lens edging apparatus in accordance with one embodiment of the present invention;
    • Figure 2A is an exploded perspective view showing the spectacle frame measuring means;
    • Figure 2B is an perspective view showing the frame holding means;
    • Figure 3 is a side view partly in section showing a detector for measuring the eyeglass frame;
    • Figure 4 is a perspective view showing a lens periphery measuring means;
    • Figure 5, 6A and 6B are explanatory views for explaining an operation of the frame measuring means;
    • Figure 7 is an explanatory view for explaining an operation of a lens periphery measuring means;
    • Figure 8 is an explanatory view for explaining lens edging;
    • Figure 9 is a perspective view showing a lens measuring means;
    • Figure 10 is a top view showing the lens measuring means;
    • Figure 11 is a sectional side elevation showing the lens measuring means;
    • Figure 12 is a sectional view of a contact portion of the lens measuring means along a line XII-XII in Figure 10;
    • Figure 13 is a sectional view of a contact portion of the lens measuring means along a line XIII-XIII in Figure 10;
    • Figure 14 is an explanatory view for explaining measurement of configuration of an edged lens;
    • Figure 15 is a perspective view showing an edged lens;
    • Figure 16 is a plane view of the lens measuring means for explaining measurement of a periphery thickness of lens;
    • Figure 17 is a schematic view of lens for showing geometric value thereof;
    • Figure 18 is a block diagram of operation and control unit; and
    • Figure 19 is a flow chart showing whole operations of the present embodiment.
    Descriptions of the preferred embodiment (General explanation of lens edging apparatus)
  • Referring to Figure 1, there is shown a grinding section in accordance with one embodiment of the lens edging apparatus of the present invention. In a grinding room 2 of a housing 1 there is provided a grinding wheel 3 comprising a roughing wheel 3a, a beveling wheel 3b having a large V-shaped groove in its periphery, and a cylindric precision grinding wheel 3c, and the wheel 3 is secured on a shaft 5 having a pulley 4. The pulley 4 is connected with a grinding motor 6 through a belt 7 so that the wheel 3 is rotated by the motor 6.
  • In the housing 1 there are provided bearing members 10, 11 which are adapted to rotationally, axially-movably hold a carriage shaft 12. One end of the carriage shaft 12 is rotationally mounted on a bearing member 21a provided on a later mentioned transfer station 20. There is provided with a carriage 13 arm members 14, 15 of which are secured on the shaft 12. On other arm members 16, 17 of the carriage 13 there is provided a work holding shaft 18 comprising a pair of shafts 18a, 18b for holding a lens LE to be edged. The shaft 18a has an operation handle 19 at its end, and by rotation of the handle 19 the shaft 18a is slided along its axis so that the shafts 18a, 18b supports the lens LE between them.
  • There is provided a lens measuring means 30 mentioned later, an arm portion 31 of which is mounted on the shaft 12 so as to swing on an axis in common with the one of the carriage 13.
  • A base plate 21 of the station 20 has a pair of wheels 22 which are adapted to roll on rails 23 secured on the housing 1 so that the station 20 is possible to move along the rails 23. The station 20 has a female screw 24 to be engaged with a' transfer male screw 41, which is rotated by a motor 40 so that the station 20 is moved in both directions as shown by an arrow 25. The shaft 12, as mentioned above, is rotationally mounted on the member 21a, and therefore the carriage 13 horizontally moves simultaneously with the station 20.
  • The base plate 21 has two vertical shafts 26, 26' parallel to each other, which movable mount a stopping member 27. The stopping member 27 has a female screw 28 to be engaged with a transfer male screw 43, which is rotated by a Z-axis motor 40 so that the stopping member 27 is moved upwards or downwards. The carriage 13 also has an arm portion 16a which mounts a rotation wheel 16b at its end, and the rotation wheel 16b is placed on an upper surface of the stopping member 27 so that the carriage 13 is possible to swing in response to a vertical motion of the stopping member.
  • [Eyeglass frame measuring means]
  • Referring to Figure 2A, there is shown means for digitally measuring a configuration of the eyeglass frame or a lens pattern previously made in accordance with the eyeglass frame. The shaft 18b is supported by a bearing member 50 formed on the carriage 13. The shaft 18b mounts a detecting arm 51 at its end 18c, and a long side frame 52 of the detecting arm 51 is mounted on an end portion 18c of the shaft 18b at right angle to a rotation axis of the shaft 18b. A detector 54 is provided on another long side frame 53 to be moved thereon and biased to the end portion of the frame 53 by a pressure spring 59 coiled around the frame 53. On short side frames 55, 56 of the arm 51 there are rotationally provided with pulleys 57, 58, respectively.
  • While, the shaft 18b rotationally supports a pulley 60 which is united with a code disc 62 of an encoder 61. A detecting head 62a of the encoder 61 is secured to an outside of the arm 16. A first wire 80 is wound around the pulley 60 and secured to the detector 54 through the pulley 57 and the side of the pulley 60 at their ends, respectively. A second wire 81 is wound around the pulley 60 in an opposite direction to the first wire 80 and secured to the detector 54 through the pulley 60 and the side of the pulley 60 at their ends, respectively, thereby, displacement of detector 54 on the frame 53 may be detected as rotation angle of the pulley 60 or the disc 62.
  • The detector 54, as shown in Figure 3, comprises a sliding seat 541 movably mounted on the frame 53, a sliding rotationed shaft 543 rotationally supported by the seat 541, and a detecting feeler 542 secured to the shaft 543. The detecting feeler 542 has a lens pattern feeler 544 and an eyeglass frame contacting wheel 546. The feeler 542 is a portion of the shaft 543, which is portionally cut out so as to form a semicircular cross section. The wheel 546 is rotationally provided on an end of a U-shaped arm member 545 which is mounted on the shaft 543. A contacting surface 544a of the feeler 544 and a contacting periphery 546a of the wheel 546 are located so as to include an axis 0, of the shaft 543. On another end of the shaft 543 a pin 547 is inserted so as to be parallel to the surface 544a, and the pin 547 engages with a stopping member 548 fixed on the frame 52 on its side surface when the detector 54 is on the first position.
  • Referring now to Figure 2A, in the carriage 13 there are provided a motor 70 for rotating the shafts 18, 18a and sprocket wheel shaft 71 having a pair of sprocket wheels to be rotated by the motor 70 at its opposite ends. The shafts 18, 18a have sprocket wheels 74, 75, resectively. Chains 76, 77 link the sprockets 72, 74, to the sprockets 73, 75, respectively, so that the shafts 18, 18a are rotated by the motor 70.
  • In the housing 1, there is further provided an eyeglass frame holding means 90, a station 91 which is located parallel to longitudinal direction of the arm member 16 at the time when the carriage 13 is on the first position. The station 91 has a pair of rails 92, 93 parallel to the longitudinal direction of the arm member 16, which movably support eyeglass frame supporting members 94, 95. The supporting members 94, 95 are always biased by a spring 96 toward each other. The supporting member 95 has a screw portion at its leg portion 95a, which engages with a transfer screw 97a provided on a shaft of a Y-axis motor 97. The supporting members 94, 95 have fitting member 94c, 95c at upper portions of arms 94b, 95b in order to fit an eyeglass frame holding member 100.
  • The holding member, as shown in Figure 2B, has a base plate 101 providing a circle opening 102 at its center, eyeglass frame holding arms 103,104 provided on the plate 101 being opposite to each other, and a pressure member 105 for pressing an eyeglass frame 200.
  • The arms 103, 104 hold upper and lower limbs of the eyeglass frame 200 and the pressure member 105 presses the lens frame 200, so that the eyeglass frame 200 is secured on the opening 102 of the member 100. At this time, a fore end 105a and a rear end 105b of the pressure member 105 are projected from concavities 103a, 104a of the arms 103, 104, thereby a fore end 101a a and a rear end 101 b (not shown in Figures) of the plate 101 are on the same plane with the ends 105a, 105b, respectively. The member 100 holding the eyeglass frame 200 is supported by the members 94c, 95c.
  • The base plate 101, the pressure member 105 and the concavities 103a, 104a are designed so that an upper edge of the rear and 106b and a lower edge of the rear end 101 b are positioned at the same distance d from a center axis of a V-shaped groove of the lower limb. The supporting members 94c, 95c have V-shaped grooves 94d, 95d, respectively. Thereby, when the holding member 100, as shown in Figure 2C, is supported by the supporting members 94c, 95c, the upper edge of the rear end 105b and the lower edge of the rear end 101b slide on surfaces of the V-shaped grooves 94d, 95d so that a center between the upper edge and the lower edge becomes coincident with a center of the V-shaped groove. In this way a center 201 b of a V-shaped groove of the lower limb coincides with the one of the supporting members 94c, 95c.
  • A template holding member 110, as shown in Figure 4, is used in the case of that a lens template 210 is supported by the supporting members 94, 95. The member 110 comprises a holding frame 111, pole members 112, 113 secured on an opposite ends of the holding frame 111, a template holding pole 111 a fixed to the frame 111 at its center, and pins 114, 115, 116 projected from the template holding pole 111 a at its end. The pattern 210 has three holes to be engaged with the pins 114, 115, 116.
  • [Operation of eyeglass frame measuring means]
  • Hereinafter, there is shown the operation of the eye glass frame measuring means described above. The eyeglass holding member 100 is held by the supporting members 94, 95, and the carriage 13 is moved by rotation of the Z-axis motor 40 in a direction of an arrow A (shown in Figure 1) by the predetermined displacement. In accordance with rotation of the Y-axis motor 97 the eyeglass handling member 100 is moved along the rails 92, 93 by the predetermined displacement and the eyeglass frame 200 is moved to the first set position so that the center 201 b of the V-shaped groove of the lower limb is in contact with the contacting wheel 546 in the same plane, and the rotation axis 01 of the detecting arm 51 is located in the eyeglass frame 200. At this time the wheel 546 is engaged with the V-shaped groove of the lower limb, and the pin 547 is released from the stopping member 548 to make the shaft 543 free of rotation. Displacement of the detector 54 along the frame 53 is converted into rotation angle to be measured by the encoder 61 through the wires 80, 81.
  • When the carriage 13 and the detecting arm 51 are located at the first position as shown in Figure 2A and the detector 54 is located at the first position as shown in Figure 5 where the detector 54 is pressed by the spring 59 not to abut on the eyeglass frame 200, an origin 0 is taken to be on the axis 01 and a distance between the origin 0 and the rotation axis 02 of the arm 51 is taken to be I. The assumption is further made that the encoder 61 counts counting value Cn in accordance with said predetermined displacement of the eyeglass frame 200 and the rotation of the detecting arm 51, the encoder 61 has e°/pulse resolution, the detector 54 has d (mm)/plate resolution in response to the resolution of the encoder 61, and rotation angle θn of the detecting arm 51 is 0° when the detecting arm 51 is positioned at the first standard position or parallel to the arm member 16 of the carriage 13. Under the present embodiment, when the displacement of the detector 54 along the detecting arm 51 is measured by the encoder 61, a radius vector ρn of the detecting arm 51 being at the rotation angle θn includes rotation of the detecting arm 51, and therefore
    Figure imgb0001
  • When the detecting arm 51 is positioned at the standard position or θn=0, the radius vector po is presented from the equation (1) as follows:
    Figure imgb0002
  • In this way digital values (ρn, θn) (n=0, 1, 2,...,N) of a configuration of the eyeglass frame 200 about the axis 02 is obtained through the rotation of the detecting arm 51 along a whole periphery of the eyeglass frame 200.
  • The values (ρn, θn) are those in the case where the rotation center 02 of the detecting arm 51 is located at any position in the eyeglass frame 200 and not in the case where the rotation center 02 is located at a geometric center of the eyeglass frame 200. Referring to Figures 6A and 6B there is shown a method to invert the former into the latter. Locating the carriage 13 at the first position, a Y-axis is taken to be line connecting between the rotation center 02 and a swing center 0 of the carriage 13, and a X-axis is taken to be one crossing the Y-axis at a right angle. On the conditions mentioned above, the eyeglass frame data (ρn, θn) under rectangular coordinate are converted into those (xn, yn) under polar coordinate through the following transforming equations (3);
    Figure imgb0003
  • From the eyeglass frame data (xn, yn) the minimum coordinate point A (xa, ya) and the maximum coordinate point C (xc, yc) in the X-axis direction and the minimum coordinate point D (xd, Yd) and the maximum coordinate point B (xb, Yb) in the Y-axis direction are selected, coordinate values 03 (x3, y3) of the geometric center 03 of the eyeglass frame 200 are calculated from the following equation (4);
    Figure imgb0004
  • Then, differences Δx, Ay between the rotation center 02 (xo, yo) under the first position and the 03 (x3, y3) are calculated from equations Δx=x0-x3, Δy=y0-y3. Shift of Δy is carried out so that the frame holding means 90 is moved by Ay by the Y-axis motor 97. While, shift of Δx is carried out so that the carriage 13 is swung by going up and down the stopping member 27 by h. Under the present embodiment a swing radius M of the detecting arm 51 is twice as long as a swing radius m of the wheel 16b,
    Figure imgb0005
    Figure imgb0006
    thereby,
    Figure imgb0007
  • The operation mentioned above leads to make the rotation center of the detecting arm 51 coincident with the geometric center 03 of the eyeglass frame 200. Subsequently, the detecting arm 51 is rotated by an angle (3 in order to shift a position of the origin. In the present condition, the detecting arm 51 is rotated along the whole periphery of the lens frame 200 again, so that the digital configuration values (ρn, θn) of the eyeglass frame 200 are obtained and memorized.
  • [Lens template measuring means]
  • Referring to Figure 7, there is shown a method for measuring the lens template which is used instead of the eyeglass frame. In Figure 7 elements corresponding to those shown in Figure 5 are with the same reference numerals and explanations thereof are omitted. To measure a configuration of the lens template 210 the feeler 544 is moved to be in contact with a periphery of the lens template 210 and the detecting arm 51 is rotated. The detecting arm 51 is shifted from the origin 0 by the predetermined distance to locate the rotation axis O2 thereof in the lens pattern 210. In case where the detecting arm 51 is rotated by angle θn from the first standard position thereof, a radius vector tρn is represented as follows:
    Figure imgb0008
    while, in case where the detecting arm 51 is positioned at the first standard position, a radius vector po is represented as follows;
    Figure imgb0009
  • In the same method as that of measuring of the eyeglass frame mentioned above, the geometric center of the lens template 210 is calculated from lens pattern configuration (tρn, θn) (n=O, 1, 2,...N), the rotation center 82 of the detecting arm 51 is moved to the geometric center and rotated along the whole periphery of the lens pattern 210, and the measured valves are memorized.
  • In this embodiment a contact point 546a between the groove of the eyeglass frame 200 and the contacting wheel 546 and the contacting surface 544a, as shown in Figure 3, are adapted to be located on the axis 0, of the shaft 543, at the measuring time the contacting wheel 546 and the feeler 544 supported by the U-shaped arm member 545 are pressed against the groove of the eyeglass or the lens template, and the member 545 is turned to a line perpendicular to a contact surface between the wheel 546 and the groove or the feeler 544 and the lens pattern. Consequently, the measurement mentioned above is always carried out with precision.
  • [Edging means and operation thereof]
  • Referring to Figure 8, there is shown an edging means for edging pre-edged lens LE in accordance with the values obtained by the above mentioned measuring means and the operation thereof. The pre-edged lens is mounted by the shafts 18, 18a (refer to Figure 1), and the motor 6 is energized, so that the pre-edged lens falls on the wheel 3 by its gravity in order to be edged thereby.
  • In accordance with the present invention the pre-edged LE is edged on the basis of the value (ρn, 8n) (n=0, 1, 2,...N) mentioned above. Displacement of the carriage 13 is measured by the linear encoder 610, which comprises a scale 611 provided on a side of the arm portion 31 of the lens measuring means 30 so as to rotate it about a pivotal point P, and a detector head 612 pivoted on the side of the carriage 13. A rotation angle y of the carriage 13 in response to displacement from the center 03 to the center 02 is the same as the rotation angle y' of the detector head 612. The rotation angle y' being equal to one of the carriage 13 is read out on the scale 611. Since the scale 611 is pivoted on the arm portion 31 at the pivotal point P, a distance between e, and 12 is substantially equal to a length c between e'1 and e2. While, the present embodiment is designed so that, suppose that a radius is equal to the length between the shaft 12 and the point P and an included angle is equal to a rotation angle of the carriage 13, a hypotenuse P in response to an arc 613 becomes equal to the length C. Thereby, the value read by the encoder 610 becomes equal to the hypotenuse P in the case where the carriage 13 is rotated by angle y, and the length Yn becomes twice as much as the above value. In this way, while each portion of the periphery in response to every radius vector po is measured, the each portion is edged until the female screw 28 of the stopping member 27 is in contact with the rotation wheel 16b. Subsequently, the motor 70 is energized by the same predetermined angle as one on measuring lens frame to make the lens LE rotate by an angle θ'n, and the lens LE is edged until it has a radius vector p'n. The operation mentioned above is carried out on every eyeglass frame value (ρn, θn) (n=0, 1, 2,...N), so that whole periphery of the lens LE is edged upon the eyeglass frame values.
  • [Lens measuring means]
  • Referring to Figures 9 through 13 there is shown the lens measuring means 30 disclosed in Figure 1. Shafts 302, 303 are fixed on a base 301 normally projected from the arm portion 31 and pivot link arms 304, 305 at their ends, respectively. Arm members 309, 310 are mounted on a link bar 306 at its ends and pivoted by the link arm 304, 305 at their other ends through shaft 307, 308, respectively. The link arm 304, 305 the link bar 306 and the base 301 form a link motion. The arm members 309, 310 have shifts 311, 312 lying parallel to the link bar 306 through deformed ellipitical frames 317, 318. Other deformed elliptical frames 313, 314 pivot the shafts 311, 312 at their ends, respectively. A U-shaped arm portion 315a of a shaft member 315 is movably engaged with the shaft 311 at its middle portion and the shaft member 315 is movably engaged with a bearing portion 316a of a moving member 316. The moving member 316 has a pin 319 on its upper surface which is movably engaged with a slit 320a of an arm member 320. The arm member 320 is pivoted by a shaft 321 projected from the base 301 at its end. In the same way, a U-shaped arm portion 322a of a shaft member 322 is movably engaged with the shaft 312 at its middle portion and the shaft member 322 is movably engaged with a bearing portion 323a of a moving member 323. The moving member 323 has a pin 319 on its upper surface which is movably engaged with a slit 325a of an arm member 325. The arm member 325 is pivoted by a shaft 326 projected from the base 301 at its end.
  • The base 301 mounts an arm motor 330 a rotation shaft of which is provided with an arm plate 331. The arm plate 331 has rotary wheels 332,333 at its opposite ends, which are pressed to each side of the arm members 320, 325. The arm member 320 mounts a detecting head 335 of an encoder 334 at its middle portion, and a scale 337 of the encoder 334 passes through the detecting head 335. The base 301 pivots a scale 337 at its end. In the same way, a detecting head 339 is mounted on the arm member 325 at its middle portion, and a scale 340 of the encoder 334 passes through the detecting head 339.
  • Two rail members 341, 342 passing through frames 313, 314 are supported by frames 317, 318 parallel to the link bar 306 so as to support the frames 313, 314. The frame 313 is engaged with a cylindric member 345 at its end into which a cylindric member 343 is rotationary inserted on a common axis thereof. The U-shaped arm portion 315a of the shaft member 315 is movably engaged with a groove 343a formed on the outer periphery of the cylindric member 343. In the same way, the frame 314 is engaged with a cylindric member 345 at its end into which a cylindric member 346 is rotationally inserted on a common axis thereof. The U-shaped arm portion 322a of the shaft member 322 is movably engaged with a groove 346a formed on an outer periphery of the cylindric member 343. A ring 347 having a bevel 347a and a ring 348 having a bevel 348 are movably mounted on the cylindric member 345. The cylindric member 345 has a groove 345a parallel to an axis thereof, and a pin 349 connects the ring 347 with the cylindric member 343 and a pin 350 connects the ring 348 with the cylindric member 346. Pins 351, 352 pulled by spring 353, as shown in Figure 11, penetrate into the cylindric members 343, 346, thereby the cylindric members 343, 346 are forced to be pulled toward each other and the rings 347, 348 linked to the cylindric members 343, 346 are also forced to be pulled toward each other.
  • [Operation of lens measuring means]
  • Referring to Figures 14 through 18, there is shown operations of the lens measuring means mentioned above. In Figure 14 the carriage 13 is returned to the first position so that the edged lens LE is brought to the predetermined position. Subsequently, an eccentric cam 360 is rotated by a driving means (not shown in Figure) so that the lens measuring means is turned about the shaft 12 to make the cylindric member 345 contact with thie periphery of the edged lens LE. Next, the rotary work holder 18 is stepwise rotated by the predetermined angle in the same manner as edging the lens, and the radius vector p' of the edged lens is measured at each stepped angle. The encoder 610 used on edging, as shown in Figure 8, was utilized for measuring the radius vector p'. However, in case of edging, the radius vector is read out by the detecting head 612 moving on the scale 611 in response to swing of the carriage 13, while on measuring the radius vector of the edged lens the radius vector, as shown Figure 14, is read out on the scale 611 moved in response to the swing of the arm portion 31 by the detecting head 612 mounted on the fixed carriage 13.
  • Referring to Figures 15 through 17 there is shown measuring of curvature and peripheral thickness of lens by the lens measuring means 30. The motor 330 is energized not to make the arm plate 331 press the arm members 320, 325, so that the cylindric members 343, 346 are moved toward each other by the spring 353. Thereby, the periphery of the lens LE is got between the rings 347, 346 linked with the cylindric members 343, 346. At this time the cylindric members 343, 346 make the arm members 320, 325 swing, and the rotation angle of the arm members 320, 325 or the displacement of the rings 347, 348 are measured by the encoders 334, 338. By energizing the motor 70 the lens LE is stepwise rotated, and the displacement of the rings 347, 348 are measured at each rotation angle of the lens LE.
  • Referring to Figure 17, suppose that fZA and fZS mean readings measured through the ring 347 at position A and B, respectivey, p'A and p'B mean radius vectors at the position A and B, respectively, and Rf means curvature radius of a front surface having a curvature center fZo on the rotation axis of the lens LE,
    Figure imgb0010
  • Suppose, further, that n means a refractive index of lens or usually 1.523, and Cf means a curve value of the front surface of the lens.
    Figure imgb0011
  • Then, the curvature radius Rf is calculated from the equation (8) and the curve value Cf is calculated from the equation (9) using the above radius Rf.
  • On the other hand, suppose that IZA, rZB mean readings measured through the ring 348, and Rr means curvature radius of a rear surface having a curvature center rZo,
    Figure imgb0012
  • Suppose that Cr means a curve value of the rear surface,
    Figure imgb0013
  • The peripheral thicknesses ΔA, ΔB of the lens LE is calculated from the following equation;
    Figure imgb0014
  • [Control circuit]
  • Referring now to Figure 18, there is shown a block diagram of control circuit for the aforementioned lens edging apparatus. The control circuit includes an oeration and control circuit 1500 comprising a micro-processor for carrying out various operations and program control, a motor control circuit 1200, a counting circuit 1100 for counting output signals of the encoders 61, 334, 339 and 610, a frame configuration memory 1300 for memorizing value signals of the eyeglass frame and the lens pattern produced by the circuit 1500, a bevel edge input and output system 1400 having an input keyboard 1401, a liquid crystal display device 1402 and an interface 1403, and a bevel edge data memory 1600. The motor control circuit 1200 is adapted to control the Y-axis motor 97, the motor 70 for rotating the lens shaft 18, the motor 1208 for rotating the lens measuring means 30, the Z-axis motor 40 for moving the carriage 13 in the Z-axis, the X-axis motor 42 for moving the stopping member 27 in the X-axis and the grinding motor 6.
  • [Whole operation of the lens edging apparatus]
  • Referring to Figure 19 there is shown the whole operation of the aforementioned lens edging apparatus.
    • (1) Eyeglass frame measuring step
      • Step 1-1: Having received starting instructions, the operation and control circuit 1500 makes the motor control circuit 1200 operate in accordance with the program memorized in a program memory to energize the motor 40, so that the detector 54 fixed on the carriage 13 is moved to the eyeglass frame holding position.
      • Step 1-2: The motor control circuit 1200 energizes the Y-axis motor 97 so that the eyeglass frame 200 is moved to be in contact with the detector 54 and further to include the rotation center of the detecting arm 51 in the eyeglass 200.
      • Step 1-3: The motor control circuit 1200 energizes the motor 70 controlled by clock pulses CP generated by a clock pulse generating circuit 1501 included in the circuit 1500, so that the detecting arm 51 is rotated. The detector 54 is moved along the periphery of the eyeglass frame 200 so as to be moved on the detecting arm 51 by the radius vector p, and displacement of the detector 54 is measured by the encoder 61 the outputs of which are counted by the counting circuit 1100. Since the counting circuit 1100 is connected with an output of the clock pulse generating circuit 1501 to receive the clock pulses therefrom, so that the circuit 1100 counts the radius vector p under synchronizing with the clock pulses or responding to the rotation angle 8 of the detecting arm 51. A set of value signals of the radius vector (ρn, θn) in a rotation of the detecting arm 51 are given to the frame configuration memory 1300 through the operation and control circuit 1500 and memorized in the memory 1300. The present step is called a pre- measuring step of a configuration of eyeglass frame.
      • Step 1-4: After the pre-measured values under the rectangular coordinate memorized in the memory 130 are converted into the one under the polar coordinate through the equation (3), the geometric center of the eyeglass frame 200 is calculated from the equation (4). The motor control circuit 1200 energizes the X-axis motor 42, the Y-axis motor42 and the motor 70 to letthe rotation center of the detecting arm 51 locate at the geometric center of the eyeglass frame 200.
      • Step 1-5: The same operation as that of the step 1-3 is carried out to get the radius vector (ρn, θn) in the case where the rotation center of the detecting arm 51 is positioned on the geometric center of the eyeglass frame. The readings are memorized in the memory 1300. The present step is called a final measuring of frame configuration.
    • (2) Roughing step
      • Step 2-1: The motor control circuit 1200 energizes the grinding motor 6.
      • Step 2-2: The motor control circuit 1200 energizes the Z-axis motor 40 so that the pre-edged lens supported by the carriage 13 is moved to be positioned on the roughing wheel 3a.
      • Step 2-3: The motor 70 for rotating the lens shaft 18 is energized in response to the clock pulse CP generated in the pulse generating circuit 1501 in order to make the shaft 18 get in the standard position (8=0). Then, the X-axis motor 42 is energized to lower the stopping member 27, thereby the carriage 13 is swung so that the pre-edged lens LE supported by the carriage 13 is contact with the roughing wheel 3a to be roughed whereby. While, the operation and control circuit 1500 receives the radius vector pe (8=0) as a standard value from the memory 1300.
      • Step 2-4: While the operation and control circuit 1500 is comparing the radius vector p measured by the encoder 610 and the counting circuit 1100 with the standard value po, the lens LE is roughed by the roughing wheel 3a positioned at the rotation angle 8=0 until the value p becomes the standard value po. When the value becomes the standard valve po, the X-axis motor 42 is energized to raise the stopping member 27 so that the carriage 13 is raised to stop roughing the lens LE.
      • Step 2-5: The motor 70 is energized so that the lens LE is rotated to get in the direction θ2. While, the operation and control circuit 1500 receives the radius vector ρ1(θ=θ1) as the standard value from the memory 1300. The X-axis motor 42 is energized to lower the stopping member 27, the carriage 13 is swinged so that the lens LE is in contact with the roughing wheel 3a. While the circuit 1500 is comparing the radius vector p thus measured with the standard value pi, the lens LE is roughed by the roughing wheel 3a positioned at the rotation angle θ=θ1 until the value p becomes the value pi. When the value p becomes the value ρ1, the X-axis motor 42 is energized to raise the stopping member 27 so that the carriage 13 is raised to stop roughing the lens LE.
  • The aforementioned operation is repeated while the value p as measured is being compared with the value ρn memorized in the memory 1300.
      • Step 2-6: after the whole periphery of the lens LE is roughed, the X-axis motor 42 is energized to let the carriage 13 return to its original position and the rotation of the grinding motor 6 is stopped.
    • (3) First lens measuring step
      • Step 3-1: In accordance with instructions from the operation and control circuit 1500, the motor 1208 is energized by the motor control circuit 1200 to rotate the eccentric cam 360, thereby the cylindric member 345 is placed on the edged lens LE by its gravity.
      • Step 3-2: The arm motor 330 is energized by the motor control circuit 1200 to make the arm members 320, 325 free, so that the rings 347, 348 are placed on the periphery of the lens LE.
      • Step 3-3: The motor 70 is energized to rotate the lens LE roughed in the way of the aforementioned steps. The encoder 610 measures the radius vector ρ'n at each rotation direction of the lens shaft 18, for example, referring to Figure 17, the radius vector ρ'A is measured at the rotation angle 8A. The outputs of the encoder 610 are counted by the counting circuit 1100 and the radius vector p'A thus counted is fed to the operation and control circuit 1500.
  • The encoder 334 measures the position of the front periphery of the edged lens LE or the value fZa at the rotation angle θA as shown in Figure 17. The outputs of the encoder 334 are counted by the counting circuit 1100 and the counted value fZa is fed to the circuit 1500. In the same way, the encoder 334 measures the position of the rear periphery of the edged lens LE or the value ,Za at the rotation angle pA. The outputs of the encoder 334 are counted by the counting circuit 1100 and the counted value ,Za is fed to the circuit 1500.
  • As a result, the circuit 1500 receives the values fZn, rAn of the positions of the front and rear peripheries of the edged lens LE, and the radius vector p'n at each rotation angle θn, the curve values Cf, Cr, of the front and rear surfaces and the peripheral thickness Δn are calculated from the equation 8 through 12 (n=0, 1, 2,...,n).
  • Step 3-4: The motor 1208 is energized by the motor control circuit 1200 to make the lens measuring means 30 return to the original position.
    • (4) Input step of curve value and bevel edge position
      • Step 4-1: Whether an output display of a V-shaped bevel edge configuration is determined by an automatic calculation or by a result calculated according to an operator's optional input is selected by the keyboard 1401.
      • Step 4-2: In reviewing the curve values Cf, C, and the peripheral thickness An calculated in the step 3-3, the best curve values and the best peripheral thickness are selected. Based on the best ones mentioned above, the cross sections of the bevel edges of the thickest and thinnest peripheral portions are displayed by the display device 1402. A curve value of the bevel edge, a shift length of the bevel edge or a distance between the front periphery and a top of the bevel edge, and the like as desired is also displayed thereby.
      • Step 4-3: The selected curve values and shift length of the bevel edge are fed through the keyboard 1401.
      • Step 4-4: The input fed through the keyboard 1401 is transferred to the circuit 1500 through the interface 1403. Based on the curve values Cf, C" the peripheral thickness Δn, and the curve value and shift of the bevel edge, the circuit 1500 calculates the cross sections of the thickest and thinnest peripheral portions which are displayed by the display device 1402 in the ways of picture images and numerals.
    Beveling step
    • Step 5-1: In the case where the operator admits that the bevel edge displayed by the device 1402 is proper a beveling starting button on the keyboard 1401 is depressed, and in accordance with the instruction given thereby, the grinding motor 6 is energized by the motor control circuit 1200, and at the same time, the bevel edge data memory 1600 memorizes the finally selected value of bevel edge, for example, the curve value and the shift as related with the radius vector (ρ'n, θn).
    • Step 5-2: The Z-axis motor 40 is energized by the circuit 1200 to let the edged lens LE supported by the carriage 13 place on the beveling wheel 3b.
    • Step 5-3: The X-axis motor 42 is energized by the circuit 1200 to lower the stopping member 27, so that the lens LE supported by the carriage 13 is downward swinged to be placed on the beveling wheel 3b and then the beveling starts.
  • The circuit 1500 controls the circuit 1200 in such a way that, while the counting circuit 1100 is counting the output of the encoder 610, the Z-axis motor 40 and the X-axis motor 42 are energized until the beveling wheel 3b performs the curve value and the shift of the bevel edge at the radius vector (ρ'n, θn) memorized by the memory 1600. The operation is repeated at every radius vector angle θn.
  • Step 5-4: After finishing the beveling at every radius vector angle θn, the X-axis motor 42 is energized to return the carriage 13 to the first position and the rotation of the grinding motor 6 is stopped.
    • (6) Second lens measuring step
      • Step 6-1: The aforementioned steps 3-1 through 3-4 are carried out to measure the radius vector (ρ"n, θn,) of the beveled lens.
      • Step 6-2: By the circuit 1500 the radius vector (ρ"n, θn) detected in the step 6-1 is compared with the radius vector (pn, 8n) memorized by the memory 1300. In case both the radius vectors are the same as each other, the display device 1402 display "finish edging". In another case, the steps 5-2 and below are carried out to bevel the lens again.
  • The invention has thus been shown and described with reference to a specific embodiment, however, it should be noted that the invention is in no way limited to the details of the illustrated structures but changes and modifications may be made without departing from the scope of the appended claims.

Claims (7)

1. A method for grinding a spectacle lens comprising steps of measuring a spectacle frame (200) to which the lens (LE) is to be fitted to obtain the radius vectors (Pn, θn) of the frame in a digitalized value and grinding the lens (LE) based on the radius vector (Pn, 8n) of the frame to obtain a peripheral configuration of the lens (LE) which conforms to the shape of the spectacle frame (200), characterized in that said method further comprises the steps of measuring radius vectors (P'n, 8n) of the lens (LE), measuring a front position (fZA, fZB) of the lens, measuring a rear position (rZA, rZB) of the lens, and calculating the thickness (AA, AB, An) and/or curvature (Cf, Cr) of the lens based on the measured results of the front position (fZA, fZB), the rear position (rZA, rZB) and the radius vectors (P'n, θn) of the lens.
2. A method in accordance with claim 1, which further comprises a step (step 4-2 in Fig. 19B) of displaying the peripheral shape of the lens (LE) at desired angular position in accordance with the calculation results (Cf, Cr, An).
3. A method in accordance with claim 1 or 2, which further comprises a step (step 5-3) of bevelling the peripheral portion of the lens based on the radius vectors (Pn, θn) of the frame (200) and the calculation results (Cf, Cr, An).
4. An apparatus for grinding a spectacle lens comprising frame measuring means (Fig. 2A-2C) for measuring a shape of a spectacle frame (200) to which the lens (LE) is to be fitted to obtain the radius vector (Pn, θn) of the frame in a digitalized value and grinding means (Fig. 1) for grinding the lens (LE) based on the radius vector (Pn, θn) of the frame to obtain a peripheral configuration of the lens (LE) which conforms to the shape of the spectacle frame (200), characterized by lens measuring means (30) including lens radius vector measuring means (301, 345, 610, 61) for measuring radius vectors (P'n, 8n) of the lens (LE), front position measuring means (334, 347, 61) for measuring a front position (fZA, fZB) of the lens (LE) and rear position measuring means (338, 348, 61) for measuring a rear position (rZA, rZB) of the lens (LE), and calculating means (1500) for calculating the thickness (AA, AB, Δn) and/or curvature (Cf, Cr) of the lens based on the measured results (P'n, θ'n, fZA, fZB, rZA, rZB).
5. An apparatus in accordance with claim 4, which further comprises display means (1402) for displaying the peripheral shape of the lens (LE) at desired angular position in accordance with the calculation results (Cf, Cr, Δn) calculated by said calculation means (1500).
6. An apparatus in accordance with claim 4 or 5, which further comprises bevelling control means (27, 40, 42, 1200, 1500) for controlling the periphery bevelling operation of the lens (LE) based on the radius vectors (Pn, 8n) of the frame (200) measured by said frame measuring means (Fig. 2A-2C) and the calculation results (Cf, Cr, Δn) calculated by said calculation means (1500).
7. An apparatus in accordance with claim 4, wherein said lens measuring means (30) comprises: a first feeler (345) adapted to contact with the outer periphery of a roughly ground lens (LE; Fig. 14, 15) ground by a rough grinding wheel (3a);
first measuring means (610) for measuring a movement position of said first feeler (345) in digitalized value as the radius vector (P'n) corresponding to a rotation angle (8n) of the roughly ground lens (LE) detected by lens rotation angle measuring means (61); a second feeler (347) adapted to contact with the front end of the periphery of the roughly ground lens (LE);
second measuring means (334) for measuring a movement position of said second feeler (347) in digitalized value (fZA, fZB) corresponding to a rotation angle (θA) of the roughly ground lens (LE) detected by said lens rotation angle measuring means (61); a third feeler (348) adapted to contact with the rear end of the periphery of the roughly ground lens (LE); and
third measuring means (338) for measuring a movement position of said third feeler (348) in digitalized value (rZA, rZB) corresponding to a rotation angle (θA) of the roughly ground lens (LE) detected by said lens rotation angle measuring means (61).
EP19840114476 1983-11-29 1984-11-29 Edge grinding method and apparatus Expired EP0143468B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP225198/83 1983-11-29
JP58225197A JPH0659611B2 (en) 1983-11-29 1983-11-29 Eyeglass lens grinding machine
JP58225198A JPH0659612B2 (en) 1983-11-29 1983-11-29 Lens grinding machine
JP225197/83 1983-11-29

Publications (3)

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EP0143468A2 EP0143468A2 (en) 1985-06-05
EP0143468A3 EP0143468A3 (en) 1985-10-30
EP0143468B1 true EP0143468B1 (en) 1988-07-27

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EP19840114476 Expired EP0143468B1 (en) 1983-11-29 1984-11-29 Edge grinding method and apparatus

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Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3678678D1 (en) * 1985-11-25 1991-05-16 Innovative Research Inc DEVICE FOR PRODUCING AN OPHTHALMIC LENS.
JPH0632892B2 (en) * 1986-02-10 1994-05-02 株式会社トプコン Lens grinding machine
US4945684A (en) * 1987-01-12 1990-08-07 Hoya Corporation Method of and apparatus for processing peripheral edge of lens for spectacles
JP2582788B2 (en) * 1987-07-02 1997-02-19 株式会社トプコン Gazuri machine
FR2636555B1 (en) * 1988-09-22 1994-07-29 Essilor Int TEMPLATE RETURNER FOR GRINDING MACHINE, PARTICULARLY FOR GLASSES
JP2770540B2 (en) * 1990-03-09 1998-07-02 株式会社ニコン Lens shape measuring device and grinding device having the same
JP2925685B2 (en) * 1990-08-02 1999-07-28 株式会社ニデック Frame shape measuring device
FR2777817B1 (en) * 1998-04-27 2000-07-13 Briot Int METHOD AND APPARATUS FOR PALPING GLASSES, AND CORRESPONDING GRINDING MACHINE

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2191453A5 (en) * 1972-06-28 1974-02-01 Asselin Robert
JPS57158829A (en) * 1981-03-27 1982-09-30 Hoya Corp Production of glasses
DE3120632A1 (en) * 1981-05-23 1983-08-18 Abdallah, Mahmoud Ahmed, 1000 Berlin Process for establishing and providing the edge shape of spectacle lenses, and device for carrying out the process
EP0092364A1 (en) * 1982-04-14 1983-10-26 The Hanwell Optical Co. Limited A method of and apparatus for dimensioning a lens to fit a spectacle frame
FR2547930B1 (en) * 1983-05-06 1987-12-24 Helbrecht Otto NUMERICALLY CONTROLLED GRINDER FOR EYEWEAR GLASS EDGES

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DE3472907D1 (en) 1988-09-01
EP0143468A2 (en) 1985-06-05
DE143468T1 (en) 1986-01-16
EP0143468A3 (en) 1985-10-30

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