JP4392140B2 - Lens grinding method and lens grinding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens grinding method and a lens grinding apparatus for controlling the grinding of an eyeglass lens.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a lens grinding apparatus, a front end portion is provided so as to be able to swing up and down around a rear end portion, and a carriage that can be moved in the left-right direction, and a pair that extends to the left and right and is held by the front end portion of the carriage A lens rotation shaft, a lens shaft rotation drive motor that rotationally drives the lens rotation shaft, a lifting drive motor that drives the front end of the carriage to move up and down, and a grinding wheel disposed below the lens rotation shaft, Some have a grindstone driving motor that rotationally drives the grinding wheel. The grinding wheel includes a rough grinding wheel, a bevel wheel, a finishing wheel, and the like.
[0003]
In such a lens grinding apparatus, a spectacle lens (raw and circular processed lens, that is, a raw spectacle lens) is held between a pair of lens rotation shafts, and the lens shaft rotation motor is formed into a lens shape of the spectacles (glasses). Data (θ_i, Ρ_i) Rotation angle θ_iRotation control is performed based on the lens shape data (θ of the glasses)._i, Ρ_i) Radial radius ρ_iBased on the rotation angle θ of the front end of the carriage, the lens rotation axis, and the spectacle lens._iThe peripheral angle of this spectacle lens is ground with the grinding wheel, and the rotation angle θ_iThe distance between the axis of rotation of the lens and the grinding wheel in the_i+ Radius of grinding wheel).
[0004]
At this time, the rotation angle θ_iThe radius of the eyeglass lens is ρ_iThis is detected by turning on the finishing switch provided on the lifting means of the carriage, and the peripheral edge of the spectacle lens is rotated by the rotation angle θ._iRadial ρ_iIn order not to be ground as above, the elevation drive motor controls the elevation drive of the carriage, the lens rotation shaft and the spectacle lens.
[0005]
By the way, the peripheral edge of the raw spectacle lens in this way is used as the lens shape data (θ_i, Ρ_i), The radius of rotation of the spectacle lens is the rotation angle θ._iRadial ρ_iA value close to (ρ_iAfter grinding rapidly to some extent with a large grinding amount up to + Δρ), the radius of the spectacle lens becomes the rotation angle θ_iRadial ρ_iGrinding is done little by little until it becomes. At this time, in order to shorten the processing time, the rotation angle θ_iAt each angle of [i = 0, 1, 2, 3,... n], the lens axis rotation motor is stopped to stop the rotation of the lens rotation axis, and each rotation angle θ is stopped in this stopped state._iThe radius is ρ_iUntil then, the raising / lowering drive motor controls the carriage, the lens rotation shaft and the spectacle lens, and the peripheral edge of the spectacle lens is ground with a grinding wheel, so-called stepping processing operation is performed.
[0006]
[Problems to be solved by the invention]
As a problem of such stepping machining operation, when stopping at a certain point, the lens axis does not rotate and the distance between the lens axis and the grindstone axis becomes small. (Processing) The area tends to increase rapidly.
[0007]
If the power of the grindstone drive motor is not higher than that due to this load, the rotation speed of the grindstone drive motor is reduced, and the reduction in the cutting speed is caused by the decrease in the relative speed of the contact point due to the decrease in the rotation speed. There was a problem that processing did not progress.
[0008]
As a means for solving this, if the finishing switch does not turn on within the set time, the point (rotation angle θ_i) The next point (rotation angle θ_{i + 1}) Was taken.
[0009]
Each point (rotation angle θ_i), The set time until the switch was turned on was determined by various conditions such as the lens material and lens thickness. However, because this set time was short, Point (rotation angle θ_{i + 1}), Or conversely, even when the switch is turned on within the set time, there are cases where the rotational speed of the grindstone drive motor is reduced.
[0010]
Accordingly, an object of the present invention is to reduce the grinding time by stopping the rotation of the spectacle lens at every predetermined angle and grinding the periphery of the spectacle lens based on the target lens shape information. An object of the present invention is to provide a lens grinding method and a lens grinding apparatus capable of preventing the rotation from being stopped and performing efficient grinding.
[0011]
[Means for Solving the Problems]
  In order to achieve the above-described object, a lens grinding method according to the invention of claim 1 includes:Each time the spectacle lens is rotated by a predetermined angle by rotating a pair of lens rotation shafts by a lens axis drive motor to rotate the spectacle lens held between the pair of lens rotation shafts, the lens axis drive motor By stoppingThe spectacle lens at every predetermined angleRotateThe peripheral edge of the spectacle lens is ground with a grinding wheel so that the peripheral edge of the spectacle lens has a predetermined radius at each rotation angle, and the spectacle lens has a predetermined radius at each rotation angle. To detect it using the machining radius detection meansFrom the machining radius detection meansDetection signal is outputWhen the detection signal is input to the control means, the control means controls the lens rotation motor to advance the rotation angle of the spectacle lens by a predetermined angle, and the grinding wheel at the rotation angle advanced by the predetermined angle. By grinding the spectacle lens according toIn a lens grinding method for ending the grinding at the rotation angle at which the detection signal was obtainedThe rotation stop time for each rotation angle of the spectacle lens is detected by the control means as the time from the start of grinding of the spectacle lens at each rotation angle, while the grinding load of the spectacle lens by the grinding wheel is a grinding load Detected by the detection means and input to the control means,At a rotation angle at which the detection signal cannot be obtainedWhen the rotation of the spectacle lens is stopped and the peripheral edge of the spectacle lens is ground by the grinding wheel, when the grinding load detected by the grinding load detection means becomes a predetermined value or more, When at least one of the rotation stop time exceeds the set time and the control means is detected,Grinding is performed by advancing the rotation angle of the spectacle lens.
[0012]
  In order to achieve the above-described object, a lens grinding apparatus according to a second aspect of the present invention is provided with a grinding wheel for grinding a spectacle lens, the spectacle lens capable of being held, and the grinding grindstone. A lens rotation shaft that can be moved up and down and rotatable, a lens shaft rotation motor that rotationally drives the lens rotation shaft, and an axis between the grinding wheel and the lens rotation shaft by moving the lens rotation shaft up and down An inter-axis distance adjusting means for adjusting the distance, a grinding load detecting means for detecting a grinding load of the grinding wheel, and a processing radius of the spectacle lens is the lens shape information (θ_i, Ρ_i) Rotation angle θ_iAt a given radius ρ_iMachining radius detecting means capable of detecting the occurrence of the detection and outputting a detection signal; and the lens rotation motor is connected to the lens shape information (θ_i, Ρ_i) Based on the rotation angle θ_iThe grinding radius of the grinding portion of the lens to be processed that contacts the grinding wheel is the rotation angle θ._iThe target lens shape information (θ_i, Ρ_i) Radial radius ρ_iThe inter-axis distance adjusting means is controlled to such an inter-axis distance asDoControl means;The control means includes the rotation angle θ. _i When the detection signal is obtained within a set time after the grinding of the spectacle lens, the lens rotation motor is controlled to rotate the spectacle lens rotation angle θ. _i The rotation angle θ is obtained by grinding the spectacle lens with the grinding wheel at a rotation angle advanced by a predetermined angle. _i Finish the grinding process atIn the lens grinding apparatus, the control means is configured to rotate at a rotation angle at which the detection signal cannot be obtained.When the rotation of the spectacle lens is stopped and the peripheral edge of the spectacle lens is ground by the grinding wheel, when the grinding load detected by the grinding load detection means becomes a predetermined value or more, When at least one of the rotation stop time exceeds the set time,The rotation angle of the spectacle lens is advanced to perform grinding.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a lens grinding apparatus that performs an initial position setting method according to the present invention will be described below with reference to the drawings.
[Constitution]
In FIG. 1, a lens processing apparatus (lens grinding apparatus) 10 includes a grinding wheel 11 and a processing chamber 12 in which the grinding wheel 11 is disposed at the lower part. A grindstone shaft 11a that holds the grinding grindstone 11 is rotatably held on a side wall 12A of the processing chamber 12 via a bearing 11b.
[0014]
The grinding wheel 11 is rotated at high speed by a motor (grinding wheel drive motor) M1 and a belt 11c. The grinding wheel 11 is composed of a flat grinding wheel 11A, a beveling wheel 11B, and the like. Specifically, as shown in FIG. 5, it is composed of a roughing grindstone for plastic, a roughing grindstone for glass, a finishing grindstone, a V-groove beveling grindstone, a mirror-finishing grindstone, and a mirror-surface V-groove beveling grindstone. .
[0015]
Carriage arms 13 and 13 of the carriage B are arranged on both outer sides of the processing chamber 12, and lens rotation shafts 14 and 14 are rotatable at upper ends of the carriage arms 13 and 13 as shown in FIG. Is provided. The lens rotation shafts 14 and 14 enter the processing chamber 12 through arc-shaped elongated holes 12c and 12c provided in the side walls 12A and 12A of the processing chamber 12, and glasses between the ends of the lens rotation shafts 14 and 14 are inserted. A lens (circular and unprocessed lens) L is clamped. The arc-shaped elongated hole is provided with a plastic arc-shaped plate (not shown) that engages with the lens rotation shafts 14 and 14, and the carriage arms 13 and 13 are pivotally moved ( The lens rotating shafts 14 and 14 are also pivoted (moved up and down) when moving up and down, and a plastic arc plate (not shown) slides in an arc shape.
[0016]
The lens rotation shafts 14 and 14 are rotated via a transmission mechanism K by a pulse motor (lens shaft drive motor, lens shaft rotation motor) P1 (see FIG. 5), and are separated from each other in the axial direction by a drive mechanism (not shown). It is like that.
[0017]
A turning shaft 13a extending in the left-right direction is attached to the lower portion (rear end center portion) of the carriage B having the carriage arms 13 and 13. The turning shaft 13a is rotatably held by the bearing block BV. Thus, the carriage arms 13 and 13 are rotatably held by the carriage base 15. The carriage arms 13 and 13 are turned by the pulse motor 55 around the turning shaft 13a, and the lens rotating shafts 14 and 14 are lowered along the arc-shaped long holes 12c and 12c by the turning. By this lowering, the spectacle lens L sandwiched between the lens rotation shafts 14 and 14 is lowered to a predetermined position and is ground by the grinding wheel 11.
[0018]
The carriage base 15 is moved in the left-right direction (Y direction) along the guide rail 16 by the pulse motor M2, and the carriage arms 13, 13 are also moved in the left-right direction by moving the carriage base 15 in the left-right direction. The eyeglass lens L moves in the left-right direction. The carriage arms 13 and 13 and the carriage base 15 constitute a carriage having lens rotation shafts 14 and 14.
[0019]
Further, an edge thickness measurement system 18 is provided in the upper portion of the processing chamber 12. The edge thickness measuring system (lens edge thickness measuring device) 18 is provided with a measuring element 41 disposed on the upper rear edge of the processing chamber 12 and the lens shafts 14 and 14 and one end integrally with the measuring element 41. The measuring shaft 42a is provided, and a measuring unit (measuring element movement amount detecting unit) 42 disposed outside the processing chamber 12 so as to be close to the upper part of the rear edge side of the side wall 12A. The measuring shaft 42a penetrates the side wall 12A and protrudes into and out of the processing chamber 4.
[0020]
The measuring element 41 includes a feeler holding member 100 and a pair of feelers 101 and 102. The feeler holding member 100 includes a continuous portion 100a extending in the left-right direction and parallel opposing pieces 100b and 100c that protrude in the same direction at both left and right ends of the continuous portion 100a. Further, the feelers 101 and 102 are attached to face the tip portions of the facing pieces 100b and 100c.
[0021]
The feeler holding member 100 is attached to a measurement shaft 42a that extends left and right through the side wall 12A. The measurement shaft 42a is held by a measurement unit 42 disposed outside the side wall 12A so as to be movable left and right. And this measurement part 42 detects the movement amount to the left and right of the feeler holding member 100 via the measurement axis 42a.
[0022]
Further, the machining chamber 12 is provided with a grooving chamfering device (grooving chamfering means) 20 as shown in FIG. The grooving chamfering apparatus 20 includes a rotating arm 21, a rotary shaft 22 that is rotatably provided at the tip of the rotating arm 21, a grooving grindstone 23 provided on the rotary shaft 22, and a chamfer. Grinding stones 24 and 25 and a drive mechanism 30 for rotating the rotating arm 21 and rotating the rotary shaft 22 are provided.
[0023]
As shown in FIG. 2, the drive mechanism 30 includes a cylindrical shaft 31 formed in a lower portion of a hollow rotating arm 21, a drive shaft 32 disposed rotatably in the cylindrical shaft 31, A motor 33 that rotates the drive shaft 32, a timing pulley 34 attached to the tip of the drive shaft 32, a timing pulley 35 attached to the rotary shaft 22, and a timing wound between the timing pulleys 34 and 35. A belt 36 and a pulse motor 37 that rotates the cylindrical shaft 31 are provided.
[0024]
A worm 31A is formed around the outer periphery of the cylindrical shaft 31, and the worm 31A is engaged with a male screw 37b formed on a drive shaft 37A rotated by a pulse motor 37. The drive shaft 37A is rotated by the pulse motor 37. When it is moved, the cylinder shaft 31 is rotated, and the rotation arm 21 is rotated about the cylinder axis 31. On the other hand, the rotation shaft 22 rotates through the drive shaft 32, the timing pulley 34, the timing belt 36, and the timing pulley 35 by the rotation of the motor 33.
[0025]
The motor 33 and the pulse motor 37 are attached to a bracket 38 provided on the side wall 12 </ b> A of the processing chamber 12.
[0026]
An inter-axis distance adjusting means (advance / retreat means) C is provided on the side of the processing chamber 12. As shown in FIGS. 1, 3, and 6, the inter-shaft distance adjusting means C is rotatably held by a bearing 40 provided on the base 15, and a rotation shaft (not shown) of the grinding wheel 11. A base board 51 rotatably attached to a shaft 50 disposed on the coaxial line, a pair of guide rails 53 attached to the base board 51 and extending upward from the upper surface thereof and orthogonal to the upper surface, and the guide A screw shaft 54 provided on the base board 51 so as to be rotatable in parallel with the rail 53, a pulse motor (elevating drive motor) 55 attached to the lower surface of the base board 51 and rotating the screw shaft 54, and a guide rail And a pedestal 56 that moves up and down along the line 53. A reinforcing member 60 is fixed to the upper end portion of the guide rail 53, and the reinforcing member 60 rotatably holds the upper end portion of the screw shaft 54.
[0027]
The cradle 56 moves up and down along the guide rail 53 by the rotation of the screw shaft 54, and moves up and down in conjunction with the up and down movement of the first cradle 56A and moves the lens rotation shaft 14 to the cradle 56. It has the 2nd receiving stand 56B held so that rotation was possible. The second pedestal 56B is provided with a photo sensor (finish sensor, machining radius detecting means) 57, and the first pedestal 56A is provided with light shielding plates 58 and 59. The light shielding plate 58 always shields light emitted from a light emitting portion (not shown) of the photosensor 57. A straight line connecting the lens rotation shaft 14 and the shaft 50 is parallel to the guide rail 53.
[0028]
On the other hand, when the lowering of the second receiving base 56B stops and the first receiving base 56A is slightly lowered with respect to the second receiving base 56B, the light shielding by the light shielding plate 58 is released and the light receiving portion (not shown) of the photosensor 57 is shown. Are configured to receive light from the light emitting section. This shielding detects that the spectacle lens L has been finished.
[0029]
A support plate 61 is attached between the base board 51 and the reinforcing member 60, and an origin sensor 62 including a photosensor for detecting the origin in the X direction is attached to the support plate 61. When the spectacle lens L is lowered to a predetermined position (the origin position in the X direction), the light shielding plate 59 shields light from the light emitting portion of the origin sensor 62, and the origin of the carriage arms 13 and 13 is shielded by this light shielding. Is detected.
[0030]
The reinforcing member 60 is provided with an origin sensor (photo sensor, revolution number detection sensor) 65 for the pulse motor 55 as a revolution number detecting means. The origin sensor 65 is provided on a disc 66 provided at the upper end of the screw shaft 54. The notch 67 is detected, and the number of pulses of the pulse motor 55 is counted based on the detection of the notch 67. After the disk 66 is rotated by the pulse motor 55, the notch 67 first opens the light shielding of the origin sensor 65 (when the origin sensor 65 detects light from the light emitting unit (not shown)). This time is used as the pulse origin of the pulse motor 55, and the number of pulses is counted.
[0031]
By the way, the cradle 56 moves up and down along a straight line connecting the center of the shaft 50 (the rotation center of the grinding wheel 11) and the center of the lens rotation shaft 14. The cradle 56 is rotatably engaged with one end of the lens rotating shaft 14, and the carriage arm 13, 13 is turned around the lower part as the cradle 56 moves up and down (advances and retreats) along the guide rail 53. It has come to do.
[0032]
The motor M1 is driven and controlled by the control device 200 via a drive circuit (motor driver) 202. The drive circuit 202 includes a current detection circuit 202a that detects a current flowing through the motor M1 as current detection means (grinding load detection means). The motor 33 and the pulse motors 37, 55, M2, P1 are controlled by a control device (arithmetic control circuit) 200 as control means shown in FIG.
[0033]
The control device 200 includes a CPU and the like, and the frame shape data output from the frame reader (lens frame shape measuring device) 101, that is, the lens shape information (θ_i, Ρ_i) And the operation of each key switch (not shown) of the operation unit 102, etc., to control the motors M1, 33 and the pulse motors 37, 55, M2, P1, etc. The operation unit 102 is provided in a main body case (not shown) of the lens processing apparatus 10, and the operation unit 102 is provided with each key switch (not shown) for performing each operation. Further, the movement amount detection signal from the measurement unit 42 is input to the control device 200. In addition, the processing data memory 201 is connected to the control device 200.
[0034]
By the way, since the base board 51 rotates around the axis 50 provided on the same axis as the rotation axis of the grinding wheel 11, the cradle 56 has the axis 50 regardless of the size of the lens L to be tested. Is moved up and down along a straight line connecting the center of the lens and the rotation center of the lens rotation shaft 14. For this reason, it is possible to accurately perform grinding without correcting the control linearity of the size of the test lens L.
[Action]
Next, the operation of the lens grinding apparatus having such a configuration will be described.
(i) Shape information (θ_i, Ρ_i)
The control device 200 receives frame shape data output from the frame reader (lens frame shape measuring device) 101, that is, target lens shape information (θ_i, Ρ_i) And read the target lens shape information (θ_i, Ρ_i) Is stored in the machining data memory 200.
(ii) Lens data input
Further, data necessary for the grinding process of the spectacle lens L such as the material of the spectacle lens and the lens diameter is input to the control device 200 using each key switch (not shown) of the operation unit 102.
(iii) Calculation of edge thickness corresponding to lens shape information
First, the spectacle lens L is held between the lens rotation shafts 14 and 14. When a machining start switch (not shown) is turned on, the control device 200 controls the operation of the measuring unit 42 to bring the feeler 101 into contact (contact) with the front refractive surface of the spectacle lens (lens to be processed) L. , Lens shape data (θ_i, Ρ_i) To control the operation of the pulse motor P1 and the pulse motor 55. That is, the control device 200 controls the operation of the pulse motor 1 so that the lens rotation shafts 14 and 14 and the spectacle lens L are in the shape data (θ_i, Ρ_i) Based on a predetermined angle [rotation angle θ_i(I = 0, 1, 2, 3,... N)]. The control device 200 controls the operation of the pulse motor 55 to rotate the screw shaft 54. When the screw shaft 54 is rotated, the first receiving table 56A, the second receiving table 56B, and the lens rotating shaft 14 are driven up and down. At this time, the disc 66 is rotated integrally with the screw shaft 54, and the notch 67 is detected by the origin sensor 65 as the disc 66 rotates, and this detection signal is input to the control device 200. The control device 200 counts the number of detection signals from the origin sensor 65 to obtain the rotational speed of the screw shaft 54, and obtains the amount of elevation of the second cradle 56B and the lens rotational shaft 14 from the rotational speed. The control device 200 determines that the distance from the elevation of the lens rotation shaft 14 to the lens rotation shaft 14 and the tip of the feeler 101 is the rotation angle θ._iRadial ρ_iBy controlling so that_iRadial radius ρ for each_iThe feeler 101 and the front refracting surface of the spectacle lens L are in contact with each other. In this way, the feeler 101 and the spectacle lens L are moved relative to each other in a contacted state.
[0035]
With such relative movement, the feeler 101 is moved to the left and right according to the curvature of the front refracting surface, and the amount of movement to the left and right is measured by the measurement unit 42 via the measurement axis 42a. The measurement signal from the measurement unit 42 is input to the control device 200, and the control device 200 determines the target lens shape data (θ based on the measurement signal from the measurement unit 42._i, Ρ_iThe coordinate position of the front refractive surface of the spectacle lens L in FIG.
[0036]
Similarly, the control device 200 controls the operation of the measurement unit 42 to bring the feeler 102 into contact (contact) with the front refractive surface of the spectacle lens (lens to be processed) L, and the target lens shape data (θ_i, Ρ_i) To control the operation of the pulse motor P1 and the pulse motor 55, the shape of the shape data (θ_i, Ρ_i) To move relative to each other. At this time, the feeler 101 is moved left and right according to the curvature of the rear refracting surface, and the amount of movement to the left and right is measured by the measurement unit 42 via the measurement shaft 42a. The measurement signal from the measurement unit 42 is input to the control device 200, and the control device 200 determines the target lens shape data (θ based on the measurement signal from the measurement unit 42._i, Ρ_iThe coordinate position of the rear refractive surface of the spectacle lens L in FIG.
[0037]
As a more specific method for obtaining the coordinate position of the front refracting surface and the coordinate position of the rear refracting surface as described above can be adopted as disclosed in Japanese Patent Application No. 2001-30279, detailed description thereof will be omitted.
[0038]
The control device 200 then determines the target lens shape data (θ_i, Ρ_iThe edge thickness Wi is obtained by calculation from the coordinate position of the front refracting surface and the coordinate position of the rear refracting surface of the spectacle lens L), and the obtained edge thickness Wi is stored in the processing data memory 201.
[0039]
Thereafter, the control device 200 determines the lens shape data (θ from the data such as the inter-pupil distance PD and the frame geometric center distance FPD based on the prescription of the spectacle lens, the amount of uplift, and the like._i, Ρ_i) Processing data (θ_i′, Ρ_i′) Is obtained and stored in the machining data memory 201.
(iV) Calculation of the thickness of the spectacle lens L
The control device 200 controls the operation of the measuring unit 42 to bring the feeler 101 into contact (contact) with the front refractive surface of the spectacle lens (lens to be processed) L, and also controls the operation of the pulse motor 55 to carry the carriage arm. By rotating the tip portions of 13 and 13 upward about the turning shaft 13a and controlling the rotation of the lens rotation shafts 14 and 14 and the spectacle lens L upward, the contact with the front refractive surface of the feeler 101 is achieved. The position is moved to the vicinity of the lens rotation shaft 14.
[0040]
Thereafter, the control device 200 controls the operation of the pulse motor 55 to rotate the tip ends of the carriage arms 13 and 13 downward about the turning shaft 13a, so that the lens rotating shafts 14 and 14 and the spectacle lens L are moved downward. , The contact position of the feeler 101 with the front refractive surface is moved from the vicinity of the lens rotation shaft 14 in the radial direction (periphery direction) of the spectacle lens L. This movement control is performed until the feeler 101 deviates from the periphery of the front refractive surface. Along with this movement control, the control device 200 obtains the movement position in the radial direction of the contact position on the front refractive surface of the feeler 101 from the driving amount of the pulse motor 55 as Ri.
[0041]
When the radial movement position Ri of the contact position of the feeler 101 with the front refracting surface changes in this way, the feeler 101 changes in the direction parallel to the axis of the lens rotation shafts 14 and 14 (left-right direction) due to the curvature of the front refracting surface. ) Is moved by Fi, and the moving amount Fi is detected by the measurement unit 42 and input to the control device 200. Then, the control device 200 stores the movement position Ri and the movement amount Fi in the machining data memory 201 in association with each other.
[0042]
Similarly, the control device 200 obtains a movement position Ri when the contact position of the feeler 102 on the rear refractive surface of the spectacle lens L is moved in the radial direction, and changes the movement position Ri in the radial direction. Accordingly, the movement amount Bi when the contact position of the feeler 102 on the rear refractive surface moves in a direction parallel to the lens rotation shafts 14 and 14 is obtained, and the movement position Ri and the movement amount Bi are made to correspond to each other. The machining data memory 201 is stored.
[0043]
Then, the control device 200 obtains the curvature of the front refractive surface of the spectacle lens L from the movement position Fi, obtains the curvature of the rear refractive surface of the spectacle lens L from the movement position Bi, and rotates the lens rotation shaft 14 of the spectacle lens L. The thickness change from the position near 14 to the periphery is obtained and stored in the machining data memory 201. If the thickness of the spectacle lens L is known, the thickness of the spectacle lens L need not be measured if the thickness of the spectacle lens L is input at the lens data input of (ii). .
[0044]
The processing data memory 201 stores in advance data of a set time Ta for one grinding based on conditions such as changes in lens material and lens thickness. Further, the machining data memory 201 stores data on the rotational speed Na under the condition immediately before the motor M1 is rotated at a rotational speed lower than a predetermined value and the motor M1 is stopped. The data of the current value Ia flowing through the motor M1 when stored is stored. The data of the current value Ia corresponding to this rotational speed Na is the rotational angle θ_iWhen the peripheral edge portion of the spectacle lens L is being ground by the grinding wheel 11 at the angle, when the rotational speed immediately before the motor M1 stops due to this grinding resistance, a load of a predetermined value or more is applied to the motor M1. The rotation angle θ of the spectacle lens_iΘ_{i + 1}Used to advance to.
(V) Calculation of set time for eyeglass lens grinding
Rotation angle θ_iThe setting time Ta of the grinding in is the material and diameter of the spectacle lens L input as described above, or the positions near the lens rotation axes 14 and 14 of the spectacle lens L determined as described above to the periphery. It is calculated | required by the control apparatus 200 using data, such as a change of thickness. That is, the set time corresponding to this data is obtained from the data of many set times stored in the machining data memory 201.
(Vi) Glass lens grinding
Next, the control device 200 rotates the motor M1, which is a grindstone drive motor, at a high speed. Further, the control device 200 detects the target lens shape information (θ_i, Ρ_i) Based on the pulse motor P1, which is a lens shaft rotation motor, the lens rotation shafts 14 and 14 with the rotation angle θ._i[i = 0, 1, 2, 3,... n] and the lens rotation shafts 14 and 14 are rotated at the rotation angle θ._iStop every time.
[0045]
At the same time, the control device 200 determines the rotation angle θ_iThen, the operation of the pulse motor 55 is controlled to rotate the screw shaft 54, and the rotation of the screw shaft 54 causes the first receiving base 56 </ b> A and the second receiving base 56 </ b> B to be driven up and down. As a result, the leading end portions of the carriage arms 13 and 13 are controlled to rotate up and down around the rotation shaft 13a, and the lens rotation shafts 14 and 14 and the spectacle lens L are rotated up and down. The grinding process with the grinding wheel 11 is the rotation angle θ_iIs started. In this grinding process, the peripheral edge of the spectacle lens L is rotated at a rotation angle θ._iRadial ρ_iIt is done in the direction.
[0046]
In such a grinding process, the disc 66 is rotated integrally with the screw shaft 54, and the notch 67 is detected by the origin sensor 65 as the disc 66 rotates, and this detection signal is input to the control device 200. Is done. The control device 200 counts the number of detection signals from the origin sensor 65 to determine the amount of elevation of the second cradle 56B and the lens rotation shaft 14.
[0047]
And the control apparatus 200 calculates | requires the center distance of the lens rotating shaft 14 and the grinding wheel 11 from this raising / lowering amount, and this center distance is rotation angle (theta) of the spectacle lens L (lens rotating shaft 14)._iIn "radial ρ_iThe peripheral edge of the spectacle lens L is ground with the grinding wheel 11 while controlling the operation of the pulse motor 55 so as to approach the “radius of the grinding wheel 11”.
[0048]
  At this time, at the rotation angle θi of the spectacle lens L (lens rotation shaft 14), when the obtained inter-axis distance becomes “the moving radius ρi + the radius of the grinding wheel 11” within the set time Ta, the rotation angle θi The grinding process ends. At the end of the grinding process, the first pedestal 56A is further lowered at the position where the distance between the axes becomes “the moving radius ρi + the radius of the grinding wheel 11”, and the light shielding plate 58 of the first pedestal 56A is moved to the photosensor. The light is lowered from between the light emitting unit 57 and the light receiving unit 57, the light shielding of the photosensor 57 is released, and a detection signal is output from the photosensor 57 to detect. That is, when the control device 200 receives a detection signal from the photosensor 57 when “the moving radius ρi + the radius of the grinding wheel 11” is reached at the rotation angle θi, the peripheral edge of the spectacle lens L becomes the moving radius at the rotation angle θi. As ρi (grinding is completed), the pulse motor 55 is operated and controlled to raise the first receiving table 56A and the second receiving table 56B, and the lens rotation shaft 14 and the spectacle lens L are raised. Eyeglass lens L from grinding wheel 11UpwardTo separate.
[0049]
Next, the control device 200 controls the operation of the pulse motor P1 to set the rotation angles of the lens rotation shaft 14 and the spectacle lens L to θ._iTo θ_{i + 1}The rotation angle to θ_{i + 1}Radial ρ_{i + 1}Is started in the same manner as described above.
[0050]
On the other hand, such a rotation angle θ_iIn the grinding process of the peripheral edge of the spectacle lens L, the radius of the spectacle lens L is ρ within the set time Ta._iIf not, the control device 200 controls the operation of the pulse motor P1 to set the rotation angles of the lens rotation shaft 14 and the spectacle lens L to θ._iTo θ_{i + 1}Proceed to Then, the control device 200 determines the rotation angle θ_{i + 1}Radial ρ_{i + 1}Is started in the same manner as described above.
[0051]
The current detection circuit 202 a detects a current flowing through the motor M 1 from a current flowing through the drive circuit 202 and inputs the detected current value to the control device 200. Then, when the current value input from the current detection circuit 202a becomes equal to or greater than the current value Ia stored in the machining data memory 201, the control device 200 determines that a load greater than or equal to a predetermined value has acted on the motor M1. The motor P1 is operated and controlled so that the rotation angle of the lens rotation shaft 14 and the spectacle lens L is θ._iTo θ_{i + 1}Proceed to Then, the control device 200 determines the rotation angle θ_{i + 1}Radial ρ_{i + 1}Is started in the same manner as described above.
[0052]
In addition, when the rotational speed of the motor M1 becomes Na or less due to the grinding wheel resistance (load to the motor M1) of the spectacle lens ML by the grinding wheel 11, it is assumed that a load of a predetermined value or more is applied to the motor M1. Similarly, the control apparatus 200 may be configured to control the grinding process.
[0053]
Such grinding is performed over i = 0, 1, 2, 3,... N (360 °), that is, over the entire circumference of the spectacle lens L, and finally the spectacle lens L is subjected to the lens shape information (θ_i, Ρ_i) To grind. Note that if there is an interpupillary distance or an uplift amount, the lens shape information (θ_i, Ρ_i) Processing information (θ_i′, Ρ_i′), And this machining information (θ_i′, Ρ_iThe same processing is performed based on ′).
[0054]
As described above, in the lens grinding apparatus described above, when the rotation of the spectacle lens is stopped at every predetermined angle to grind the peripheral edge of the spectacle lens, if the lens rotation stop time exceeds a predetermined set time, A function to advance to the next point without completing the processing of the grinding point even when the rotation speed data of the grinding wheel drive motor falls below a certain threshold value, based on the grinding process by advancing the rotation angle of the lens Have
[0055]
In addition, this lens grinding machine can be set for a longer period of time for constant time control, and various conditions related to grinding performance (grinding wheel rotation speed, processing pressure, etc.) can be set somewhat overloaded. As a result, the entire processing can be completed in a short time with efficient processing using the grinding wheel and the power of its rotary motor.
(Other)
In the embodiment described above, when the spectacle lens L is ground by the grinding wheel 11, the grinding resistance (grinding load) of the spectacle lens L by the grinding wheel 11 changes, and the rotation of the motor M <b> 1 that rotates the grinding wheel 11 rotates. Focusing on the fact that the current value flowing through the motor M1 changes due to the fluctuation, the current value flowing through the motor M1 is detected by the current detection circuit 202a provided in the drive circuit 202 of the motor M1, thereby causing the motor M1 to Although the grinding load which acts is detected, it is not necessarily limited to this configuration.
[0056]
For example, when the rotational speed of the motor M1 is detected by a rotational speed detection means (grinding load detection means) such as a rotary encoder, and the rotational speed becomes equal to or lower than the rotational speed Na, the control device 200 operates the pulse motor P1. The rotation angle of the lens rotation shaft 14 and the spectacle lens L is controlled by θ_iTo θ_{i + 1}The rotation angle θ_{i + 1}Radial ρ_{i + 1}This grinding process may be started in the same manner as described above.
[0057]
The motor M1 may be a motor having a rotational speed detection function such as a DC brushless motor or an inverter motor that requires a dedicated motor driver (motor drive circuit). In this case, the rotational speed of the motor M1 is detected from the motor driver and input to the control device 200. When the rotational speed of the motor M1 becomes Na or less from this detection signal, the control device 200 causes the pulse motor P1 to be detected. The rotation angle of the lens rotation shaft 14 and the spectacle lens L is set to θ by controlling the operation._iTo θ_{i + 1}The rotation angle θ_{i + 1}Radial ρ_{i + 1}This grinding process may be started in the same manner as described above.
[0058]
【The invention's effect】
  Explained abovedidThe lens grinding method of claim 1According toBy stopping the rotation of the spectacle lens at every predetermined angle and grinding the peripheral edge of the spectacle lens based on the target lens shape information, the grinding time can be shortened, and the grinding wheel can be prevented from rotating during this grinding. Thus, efficient grinding can be performed.
[0059]
  Further, the lens grinding apparatus of the invention of claim 2According toBy stopping the rotation of the spectacle lens at every predetermined angle and grinding the peripheral edge of the spectacle lens based on the target lens shape information, the grinding time can be shortened, and the grinding wheel can be prevented from rotating during this grinding. Thus, efficient grinding can be performed.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a lens grinding apparatus of the present invention.
2 is an explanatory view showing a configuration of a drive mechanism of the lens grinding apparatus of FIG. 1. FIG.
FIG. 3 is an explanatory diagram showing a configuration of an inter-axis distance adjusting unit.
FIG. 4A is an explanatory view schematically showing a configuration for supporting an inter-axis distance adjusting means.
(B) It is explanatory drawing which showed the axis | shaft of the center distance adjustment means hold | maintained at the bearing.
FIG. 5 is a perspective view showing a lens shaft rotating mechanism.
FIG. 6A is an explanatory view schematically showing a configuration for supporting an inter-axis distance adjusting means.
(B) It is explanatory drawing which showed the axis | shaft of the center distance adjustment means hold | maintained at the bearing.
FIG. 7 is a block diagram showing a configuration of a main part of a control system of the lens grinding apparatus.
[Explanation of symbols]
L ... Eyeglass lens
M1 ... motor (grinding wheel drive motor)
P1 ... Pulse motor (Lens axis drive motor, Lens axis rotation motor)
11 ... Grinding wheel
14 ... Lens rotation axis
56 ... Pulse motor
57 ... Photosensor (machining radius detection means)
200 ... Control device (control means)
202... Revolution detection sensor (revolution detection means)

Claims (2)

Each time the spectacle lens is rotated by a predetermined angle by rotating a pair of lens rotation shafts by a lens axis drive motor to rotate the spectacle lens held between the pair of lens rotation shafts, the lens axis drive motor By stopping, the spectacle lens is rotated by a predetermined angle to be stopped, and the peripheral edge of the spectacle lens is ground with a grinding wheel so that the peripheral edge of the spectacle lens has a predetermined moving diameter at each rotation angle. ,
It is detected using the machining radius detection means that the spectacle lens has reached a predetermined radius at each rotation angle, and a detection signal is output from the machining radius detection means, and the detection signal is sent to the control means. When inputted, the control means controls the lens rotation motor to advance the rotation angle of the spectacle lens by a predetermined angle, and the spectacle lens is ground by the grinding wheel at the rotation angle advanced by the predetermined angle. In the lens grinding method of ending the grinding at the rotation angle at which the detection signal was obtained ,
The control means detects the rotation stop time for each rotation angle of the spectacle lens as the time from the start of grinding of the spectacle lens at each rotation angle, while detecting the grinding load of the spectacle lens by the grinding wheel Means to detect and input to the control means,
When the rotation of the spectacle lens is stopped at a rotation angle at which the detection signal cannot be obtained and the peripheral portion of the spectacle lens is ground by the grinding wheel, the grinding load detected by the grinding load detection means is a predetermined value or more. The control means advances the rotation angle of the spectacle lens and grinds when at least one of the spectacle lens rotation stop time exceeds the set time and the spectacle lens rotation stop time exceeds a set time. A lens grinding method characterized by the above. A grinding wheel for grinding a spectacle lens;
A lens rotation shaft which is provided so as to be able to hold the spectacle lens and which can be raised and lowered with respect to the grinding wheel and is rotatable;
A lens shaft rotation motor that rotationally drives the lens rotation shaft;
An inter-axis distance adjusting means for adjusting the inter-axis distance between the grinding wheel and the lens rotating shaft by raising and lowering the lens rotating shaft;
Grinding load detection means for detecting the grinding load of the grinding wheel,
Processing radius detecting means capable of detecting that the processing radius of the spectacle lens becomes a predetermined radius ρ _i at the rotation angle θ _i of the lens shape information (θ _i , ρ _i ) and outputting a detection signal. When,
The lens rotation motor is controlled based on the target lens shape information (θ _i , ρ _i ) so that the peripheral edge of the lens to be processed is brought into contact with the grinding wheel at a rotation angle θ _i and is ground. The distance between the axes is adjusted so that the radius of the grinding portion of the lens contacting the grinding wheel becomes the radius ρ _i of the target lens shape information (θ _i , ρ _i ) at the rotation angle θ _i. Control means for controlling the means ,
Wherein, when said detection signal is obtained within said at rotation angle theta _i to start grinding spectacle lenses set time, the rotation angle of the spectacle lens by controlling the lens rotating motor theta _i In the lens grinding apparatus for finishing the grinding process at the rotational angle θ _i by grinding the spectacle lens by the grinding wheel at the rotational angle advanced by a predetermined angle ,
The control means stops the rotation of the spectacle lens at a rotation angle at which the detection signal is not obtained , and grinds the grinding load detected by the grinding load detection means when the peripheral edge of the spectacle lens is ground by the grinding wheel. When at least one of the load of the spectacle lens exceeds a predetermined time and when the rotation stop time of the spectacle lens exceeds a set time, the rotation angle of the spectacle lens is advanced to perform grinding processing A lens grinding machine characterized by

Images