JP2612285B2 - Lens grinding method and apparatus therefor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens grinding method for grinding a dough lens according to the shape of a spectacle frame, and an apparatus therefor, a so-called balling machine. More specifically, the present invention relates to a method and an apparatus for beveling a lens to be processed.

(Prior Art) Generally, in order to mount a spectacle lens on a lens frame of a spectacle frame, it is necessary to bevel the peripheral portion of the spectacle lens. FIG. 9 and FIG. 10 schematically show the principle of beveling a cloth lens. In FIGS. 9 and 10, when a bevel D having a radius of curvature Re and an acute angle is processed on the periphery of the fabric lens L, the moving radius γ _A
The distance between the axes of the lens rotation axis OL and the beveling grindstone E on the meridian having the axis _L is l _A , and the lateral movement position of the lens L is Y _A.

Further, in this material lens L, when attached the position corresponding bevel D of the radius of curvature Re in meridian, the center distance l _B in the conventional lens edging machine _{l B = l A -x = l} A - ( the lateral movement positions of the lens L has been configured to Y _B is moved by y as well as changing the gamma _{a-gamma B)} only.

(Problems to be solved by the present invention) By the above-mentioned beveling, the bevel having the radius of curvature Re can be machined over all the diameter lines of the fabric lens L because the fabric lens L and the grindstone E can be processed as shown in FIG. This is only the case where the contact is made on the straight line X connecting the respective axes O _L and Oe, that is, when the fabric lens L is processed into a circular shape.

However, since the fabric lens L is three-dimensionally curved, for example, as shown in FIG. 11, in a general non-circular coarse ground lens L, the diameter of the coarse ground lens L (This radial The notation indicates angle information as well as its length, and the suffix Is the unit angle Δθ of the radius from the straight line X In the direction of. Hereinafter the same) is in contact with the grindstone E on a line offset angle α from the line X, which is the processing point P _i. Moreover, such a diameter wire Is shifted from the axis X as shown in FIG. 11, the center of the processing edge of the coarse grinding lens L and the center of the beveling grindstone E are slightly shifted in the horizontal direction as shown in FIG. 12, that is, in a direction parallel to the axis Oe of the beveled grindstone E. Will be. Therefore, when beveling a general non-circular rough grinding lens L as shown in FIG.
Radius The horizontal machining edges center of movement position Y _i in the rough grinding the lens L in accordance moved to, if rough grinding the lens L and beveling, ideal bevel with is made on the periphery of the rough grinding the lens L.

However, actually, the coarsely ground lens L is Since there is only moved laterally to move the position Y _'i corresponding to bevel the lens after processing is "rear bevel" shifted slightly to the right as Figure 12. And such deviation from the ideal bevel position is This becomes more remarkable as the angle α between the straight line and the straight line X including.

As a method of solving this conventional disadvantage, a lens position detecting device is provided at a position close to the grindstone, whereby the front and rear positions of the lens edge are brought into contact with each other, and the lens edge thickness is obtained from the carriage movement position and the difference at that time. Japanese Patent Laid-Open No. 58-1772 discloses a lens processing method and apparatus for controlling the amount of lens movement during bevel processing based on the obtained lens edge thickness.
No. 56 discloses this.

Further, as in the method disclosed in Japanese Patent Application No. 58-225197 by the present applicant and the method disclosed in Japanese Patent Application No. 60-115080, the lens surface close to the lens edge after rough grinding is removed. By contacting the filler of the type sandwiched from the front and back, and detecting the amount of movement of the filler as a pulse from the pulse generator cooperating with it and synchronizing with the rotation of the lens,
There is known a lens processing method and apparatus that measures the edge position and the edge thickness and controls the lens moving amount at the time of beveling.

Such a conventional lens edge measuring method and apparatus require a dedicated large-scale device for measuring the same,
Further, when a position detector is located at a position close to the grindstone as disclosed in JP-A-58-177256, a measurement error is likely to occur due to the influence of grinding water, grinding pieces and the like.

(Object of the Invention) The present invention solves the drawbacks of the conventional lens edge thickness measuring method and the device therefor, and measures the lens edge thickness and beveling based thereon without specially providing a large-scale device dedicated to lens edge thickness measurement. It is an object of the present invention to provide a lens grinding method capable of performing control accurately and an apparatus therefor.

(Constitution of the Invention) In order to achieve this object, a first invention is to provide processing radius information (L _i , θ _i ) of a lens to be processed with its radius A first stage to be determined in correspondence with the above, and a lens descending amount (χD _i ) and an axial moving amount of the lens fixed shaft when the front and rear edges of the rough-ground workpiece come into contact with the beveled grindstone. (Y _fi , Y _bi ) Based on the second step obtained in correspondence with the above, and the machining radius information (▲, ▼), the lens descent amount (量 D _i ), and the axial movement amount (Y _fi , Y _bi ), The above radial radius when beveling the lens to be processed To find the amount (y _i ) of moving the lens axis corresponding to
And the radial movement of the template during beveling of the lens to be processed. Moving the lens to be processed in the axial direction of the lens by the amount of movement in the axial direction (y _i ) in accordance with the formula (1), and performing a beveling process.

In order to achieve the above object, a second invention is directed to a pair of coaxially rotatable lens axes capable of holding a lens to be processed, a rough grinding wheel for rough grinding of the lens to be processed, and In a lens grinding device having a beveling wheel for beveling the edge of a processed lens, processing radius information of the lens to be processed (▲ ▼, ▲ ▼)
The radial Means for determining in accordance with the following, and when the lens rough-ground by the rough whetstone comes into contact with the beveled whetstone at the front and rear edges thereof, the respective lens descent amounts (χD _i ) and the axial movement amount of the lens shaft (Y _fi , Y
_bi ) the radial Based on the processing radius information (▲, ▼), the lens descent amount (χD _i ), and the axial movement amount (Y _fi , Y _bi ). The above radius when beveling Means for determining the amount (y _i ) of moving the lens axis corresponding to the following; Means for moving the lens to be processed in the axial direction of the lens axis by the amount of movement in the axial direction (y _i ).

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Device Configuration FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is an external perspective view showing the configuration of a lens processing apparatus, that is, a ball mill, according to the present invention, together with an electric circuit block diagram of a bevel processing control system.

The casing 10 is provided with a grindstone chamber 11, in which a grindstone rotated at high speed by a motor (not shown) is stored. This whetstone is composed of a rough whetstone 12 and a bevel whetstone 13. A bearing 14 is provided behind the housing 10, and a carriage turning shaft 21 is fitted into the bearing 14 so as to be rotatable and movable in the axial direction. The rear end of the carriage 20 is fixed to the carriage pivot 21. Thus, the carriage 20 can turn around the carriage turning shaft 21 and can slide in the axial direction. The free ends of the carriage 20 hold lens axes 22a and 22b arranged coaxially, and the lens L to be processed is held between the lens axes 22a and 22b. The lens shafts 22a and 22b are rotated by a lens shaft motor 25 disposed in the carriage 20 via a known rotation transmission mechanism Q. A template T is attached to the other end of the lens shaft 22b by well-known template holding means 24.

On the side of the housing 10, there is an L-shaped arm member 30 which is a carriage lateral moving means. The arm member 30 is slidably supported by an axial rail member 15 protruding from the side wall of the housing 10. Further, a pivot shaft 21 of the carriage is attached to one end 34 of the arm member 30 so as to be rotatable but not to move laterally. The arm member 30 is further screwed with a feed screw 33 attached to a motor 32 for lateral movement (Y-axis) on the fixed frame side (not shown). The rotation of the motor 32 moves the arm member 30 along the Y axis, and the movement of the arm member causes the carriage 20 to move in the same direction by the same amount. At the other end of the arm member 30, a pulse motor 200 as an X-axis motor is held, and a mold receiving stand 38 having a structure described later is attached. The mold receiving table 38 has a mold receiving body 38b and a contact piece 38c for contacting the template.
38c is supported at one end of the mold receiving body 38b via a shaft 207. Moreover, the template T is located on the upper surface of the mold receiving table 38, that is, the mold receiving surface 38.
It is configured to abut a. Here, the mold receiving surface 38a has the same radius of curvature as the grinding line of the beveling grindstone 13.

Further, a spring 206 is interposed between the abutment piece 38c of the mold receiving body 38, and the abutment piece 38c is lifted up by the spring 206 when the template T does not abut on the mold receiving surface 38a. Have been. Further, a light-shielding bar 205 is passed to the contact piece 38c. Mold support 38
A detector 204 is provided on the upper surface of the light emitting element 204. The detector 204 includes a pair of a light emitting element 204a and a light receiving element 204b that can block an optical path with the light-shielding rod.

The female screw 203 fixed to the lower surface of the mold receiving base 38 is the arm member 3
0 is slidably inserted into the hole, and the pulse motor 200
Is screwed with the feed screw 201 attached to the. A guide rail 202 is attached to the lower surface of the mold receiving body 38b, and is inserted into a guide hole 208 of the arm member.

The beveling control device 100 includes a counter 301 controlled by a signal from the detector 204 to count pulses from the pulse generator 103, an arithmetic circuit 106 including a microprocessor receiving count data from the counter 301, and an arithmetic circuit. A memory 110 for storing the calculation result of 106, a control circuit 108 for controlling the motors 25, 32 and the like during beveling, a calculation program memory 107 for storing a calculation program,
A sequence program memory 120 for storing a machining control sequence, a curve input device 121 for inputting a bevel curve value to the arithmetic circuit 106, a determination circuit 302 for determining the amount of descent of the mold receiving table 38, and a drive for driving the motor 32. Driver 104
A driver 102 used to drive the lens axis motor 25,
It comprises a driver 300 used to drive the pulse motor 200 and the like.

The detailed configuration and operation of the beveling control device 100 will be described in the following operation description.

Operation Step 1 In FIG. 1, the template T is mounted on the lens shaft 22b of the carriage 20 shown in FIG.
Are held at an initial home position as shown in FIG. 1 by known holding means (not shown). In this state the control circuit
108 controls the driver circuit 300 to control the pulse generator 103
Is supplied to the pulse motor 200, the pulse motor 200 is rotated forward, and the mold receiving table 38 is raised. At this time, the number of pulses supplied to the pulse motor 200 is
Counted at 01.

When the contact piece 38c of the mold receiving table 38 contacts the template T, the detector 204 outputs the detection signal to the counter 301 as the stop signal S, and stops the pulse coefficient of the counter 301. The counter 301 inputs the count value at that time to the arithmetic circuit 106.

Here, as shown in FIG. 3, the mold receiving surface 38a of the mold receiving table 38 is provided.
Is the bevel groove bottom 13 of the bevel grindstone 13 as shown by the two-dot chain line.
It has a radius of curvature that matches the radius of curvature R of a. When the rotation center or the lens axis 22a of the lens L, and a predetermined distance between the rotation center O _L and the grindstone groove bottom 13a and 22b is M, the mold cradle 38 is raised, the type receiving surface 38a is the template T and when the amount of movement of the mold pedestal 38 when in contact with the e _i, inter-axis distance between the rotation axis Oe of the lens 23 and the grindstone 13 L ₀ ≒ L is between the axial distance L, the axial distance M, L = M + R is given from the grinding wheel radius R.

And the radial diameter of the template T Center distance l _i from the increased amount e _i type cradle _{l i = (M-e i} ) + R ......... (7) ( where in, i = 0,1,2,3, ... j ... N The first memory of the memory 110 is obtained by the arithmetic circuit 106 as
Die plate radius corresponding to 111 It is stored at the address.

When this is completed, the control circuit 108 then proceeds to the driver 300
Is controlled to reverse the motor 200 and lower the mold receiving table 38 by a predetermined Δd. Then, the motor 25 is rotated via the driver 102, and the template T is moved by the unit angle Δθ as shown in FIG. Rotate and rotate the template plate Is located on the straight line X. Then, when the template T is rotated by the unit angle, the control circuit 108 outputs a reset signal to the counter 301 to reset the counter 301. If there is a detection output from the detector 204 during this unit angle rotation, the judgment circuit 302
Receiving the command, the mold receiving table 38 It is determined that it does not fall below the length of the
Output to 108. The control circuit 108 receives the command from the determination circuit 302, and further lowers the mold receiving table 38. Further, when the lens shafts 22a and 22b are rotated by a unit angle, the motor 200 is rotated forward again via the driver 300, and the mold receiving base 38 is raised, and the radial Measuring the axial distance l _{i + 1} of the. Hereinafter, this is repeated, and Between the axes l _i Ask for.

And the total radial The distance between the axes (l _i ) is stored in the first memory 111 in the template radial direction. Means address Respectively.

Step 2 Next, the arithmetic circuit 106 is stored in the first memory 111 according to the arithmetic program memory 107. The inter-axis distance data (l ₀ ) of the address is read, and as shown in FIG. 4, the radius R of the grinding line 13a of the bevel grinding wheel 13 and the inter-axis distance l _0.
Radial from Determine the distance of the virtual to the machining point P ₀ of the. That is, the rotation axis center O _{L of the} beveling grindstone 13 and the rotation axis center O _L of the lens axes 22a and 22b
The straight line connecting the door to the reference line X, when the intersection of the grinding line 13a of the reference line X and the grindstone 13 and the virtual machining point P _0, the arithmetic circuit 106 is a lens rotation center O _L virtual working point from P ₀ The distance to [ Use to stop. In this step Radius specified as Virtual machining radial length Is from equation (3) Is required.

Step 3 Next, the arithmetic circuit 106 sets the lens axes 22a and 22b to the unit rotation angle Δ
θ rotation, that is, l _{j + 1} (in this step, l
_{0 + 1} = l ₁ ) Load center distance l ₁ of the address from the first memory 111, the radius vector in the inter-axis distance l ₁ Virtual machining radius of virtual machining point P ₁ Using To share.

Figure 4, instead of the template T is a unit angle Δθ rotation in order to facilitate understanding this relationship, by Δθ rotation of the grindstone 13 to the lens axis O _L times despite grinding wheel grinding line at that time 13
a is shown as being in contact with the template T. These two notations show the same phenomenon.

Step 4 Next, the virtual machining radial length obtained in step 2 And virtual machining radial length obtained in step 3 Compare with At this stage Because Compare with The symbol “/” in the flowchart of FIG. 2 means that the values before and after that are compared (the same applies hereinafter). And Ie In the case of, the process proceeds to step 10 described later. Also, Ie In the case of, the process proceeds to the next step 5.

In the example of FIG. Then, the process proceeds to the next step 5.

Step 5 The value of l _{j + 2} (in this step, l _{0 + 2}本 l ₂ ) when the template is simply rotated by the unit angle Δθ The arithmetic circuit 106 calculates the inter-axis distance data (l ₂ ) of the address in the memory 111.
From the virtual machining radius using the above formula (4) Step 6 Virtual machining radial length in Step 4 And the virtual machining radial length in step 5 Compare with At this stage Because When Compare with And In the case of, move to the next step 7, If so, the process proceeds to step 6 '. In the example of FIG. Then, the process proceeds to the next step 7.

Step 6 'If the previous step 6 Ie When this step is performed, the axis of the distance data {l _{(j + 1) +2} , θ _{(j + 1) +2} } corresponding to the rotation of the template T by the unit angle Δθ is obtained. Virtual machining radius from the distance l _{(j + 1) +2} Is required. And that is the previous data Is compared to Until the virtual machining radial length based on the updated inter-axis distance becomes larger than the virtual machining radius length of the immediately preceding inter-axis distance, the virtual machining radial length is sequentially determined based on the successive inter-axis distance data. Seeking and comparing.

Step 7 In the previous step 6 Is determined, The radial Is determined to be the processing radial length actually processed by the grindstone 13 in. In this stage, that is, in the example of FIG. The radial Radial machining length at Is determined.

Step 8 The arithmetic circuit 10 calculates the machining radial length determined in the previous step 7. Working radial length data (▲ ▼, ▲ ▼) as a set of the lens axis rotation angle θ _{j + 1} corresponding to the inter-axis distance l _{j + 1}
Is stored in the second memory 112 of the memory circuit 110. In the example of FIG. Machining radius (▲ ▼, ▲ ▼) is the template radius Corresponding to the second memory 112 Stored at the address.

Step 9 Total radius of template T Steps 3 to until the working radial length is obtained for
8 for each radial Execute for For example, in the example of FIG. Radial machining data (▲ ▼, ▲ ▼) was obtained for Radial from Move to a new radial Perform steps 3 to 8 above for The working radial length of the workpiece is determined and the result is stored in the second memory 11.
Radius of template plate on 2 Corresponding to Store the address. Follow the same procedure to final radius Are calculated up to the processing radial length (▲, ▲) for Store the address.

Machining radius data (▲ ▼, ▲ ▼) and template radius FIG. 6 shows the relationship. The template T is the lens axis 22a, 22b
Is rotated about the axis Oe, and the rotation amount _i XΔ from the reference line H of the template.
Radius of template in the direction of θ When but positioned so as to be positioned on the reference line X, the lens L is lowered by lowering the point P _i and the grinding line 13a of the grindstone 13, the processing radius vector length of the processed wire ▲ ▼, machining angle ▲ ▼ Becomes

Step 10 In step 4 above Then, the process proceeds to this step, and as shown in FIG. 5, the first memory 111 of the rotation angle θn obtained by inverting the template T by the unit angle Δθ around the lens axes 22a and 22b is used. Virtual machining radius length from equation (4) based on the distance ln between axes at the address Ask for. In the example shown in FIG. Using the distance l _0-1 ≡ln Asking.

Step 11 Virtual machining radial length obtained in step 2 And the virtual machining radius determined in step 10 above Compare with And In the case of, move to the next step 12, In the case of, the process proceeds to step 11 '. In the example of FIG. Is Ie Is compared with If so, the process proceeds to the next step 12.

Counting step 11 ' Migrated to the step to be determined, the arithmetic circuit 106 distance between the center distance data obtained while further template T lens axis O _L times despite the the unit angle Δθ reversed, i.e. new axis l _j-1
Equation (4) using the inter-axis distance l _{(j-1) -1} (not shown) of the inter _- axis distance data (l _{(j-1) -1} , θ _{(j-1) -1} ) With virtual machining radial length Is calculated and the previous virtual machining radial length is calculated. To be compared. This operation is repeated until the sequentially updated virtual machining radius becomes smaller than the immediately preceding virtual machining radius.

Step 12 In the previous step 11 At this time, the process moves to this step. Then, the arithmetic circuit 106
Is The radial Machining radius length actually processed by whetstone 13 above Is determined, and the rotation angle θ of the template T corresponding to the axis distance l _j is determined.
Combined with _j , machining radial length data (▲ ▼, ▲
▼).

In the example of FIG. Since these are determined as the machining radius length, the machining radius length data (▲ ▼, ▲ ▼) And data (▲ ▼, ▲ ▼) is obtained. It is stored at the address.

When step 9 is executed, each radius of the template T For each machining radius data (▲ ▼, ▲ ▼), (▲
▼, ▲ ▼), (▲ ▼, ▲ ▼), (▲
▼, ▲ ▼),… (▲ ▼, ▲ ▼) ……
(▲ ▼, ▲ ▼) are obtained, and these are the corresponding template plate radials of the second memory 112. Show address Is stored.

Step 13 A known rough grinding process is executed by the rough grinding stone 12 following the template T.

Step 14 The control circuit 108 reads any four template radials from the second memory 112. Select The first template radial Drives the motor 25 via the driver 102 based on
The lens axes 22a and 22b are rotated by (aXΔθ), and the reference line X
Radius of template T on (X axis) To be located.

Next, the control circuit 108 drives the motor 200 to
It is detected whether or not the coarsely ground lens L, which has been coarsely ground in the previous step 12, comes into contact with the beveling grindstone 13 as shown in FIG. 7A.

At this time, the contact point S of the lens L to the beveled grindstone 13 is determined by the radial movement of the template plate as schematically shown in FIG. 7 (B). Corresponding to the second memory 112 Machining radial length data stored at the address (▲ ▼, ▲
▼) Machining angle ▲ ▼ Direction (now this radial Is on the X axis), that is, on the processing line K rotated by ▲ from the X axis.

A predetermined number of pulses corresponding to a predetermined reference height χD is supplied from the pulse generator 103 to the motor 200 via the driver circuit 300 under the control of the control circuit 108, and the number of pulses is reduced to the reference height χD. The cradle 38 is lowered. At this time, the motor 20
The number of pulses supplied to 0 is counted by the counter 301. Whetstone 13
Is a two-stage V-shaped grindstone 13 'as shown in FIG. 7 (C), so-called "medium V grindstone", .DELTA.D is set to the gentle slopes 13b' and 13c '. If no contact is made at this time, the determination circuit 302 determines that the contact is non-contact because the detector 204 does not generate an ON signal even if the predetermined number of pulses are supplied from the pulse generator 103, and the control circuit 108 Output to The control circuit 108 includes a motor
200 is inverted to return the lens axes 22a and 22b to the initial height. Then, the control circuit 108 operates the motor 32 to move the seventh minute distance in the unit minute distance Y-axis direction (axial direction of the lens axis).
After leftward on the figure to move the carriage 20, and re-execute the above operation, the lens front edge end L _f are repeated until contact at the reference height χD the front grinding surface 13b of the grindstone 13. When the reference height χD is reached, the detector 204
It outputs an ON signal and a stop signal S to the counter 301. The number of pulses supplied from the pulse generator 103 to the motor 32 is counted by a counter 301, and the counter 301 has a double structure capable of independently counting the number of pulses supplied to the motor 200 and the motor 32. Judgment circuit 30
The control circuit 108 that has received the signal from 1 sends the count value of the counter 301 to the arithmetic circuit 106 and temporarily stores it in an internal memory (not shown) in the arithmetic circuit 106. At the point of contact at the reference height ΔD, this is used as the lens movement amount Y _fi in the third memory 1.
13 Radius of template (In the case of the present embodiment, _Is stored as _Yfa . ). The counter 301 has been reset at that time. While lowering the mold cradle 38 for the first time, in the course of falling to the reference height KaiD, when the front edge end L _f of rough grinding already lens L abuts, in order to lower the mold cradle 38 Pulse generator 103
The number of pulses supplied to the motor 200 from the counter 301
The counting is stopped at the point of contact by the stop signal from the detector 204. Control circuit 108 receives a signal from the determination circuit 302 sends the count value of the counter 301 at that time to the arithmetic circuit 106, as compared to the reference height KaiD, the inclination angle epsilon ₁ of V-shaped grinding wheel from the difference ΔχD On the basis of Then, the Y movement ΔY that stops is sent to the control circuit 108, and after moving the Y movement Y rightward in the lens axis direction, the same operation is repeated again.

Then, until the side edge end L _b is the reference height χD of the lens L (the reference height χD is no problem different from the time of measurement of the front edge end L _f.), Edge end L _b The cradle 38 is lowered while detecting whether the abutment comes into contact with the front grindstone surface 13c of the grindstone 13. Here below in advance edge end L _f does not contact the front grinding surface 13b of the grinding wheel 13 positions, it goes without saying to keep moving the carriage to the right.

Operation of the latter is similar to the case of measuring the lens edge end L _f, only the movement in the Y direction is the opposite direction. Reference height χD
Template radial Y-direction movement value when it becomes the third memory 113 as Y _bi (In the case of the present embodiment, the radial _Is stored as Y _ba ).

The same applies to the template radial The above operation is executed for the corresponding Y movement amounts Y _fb , Y _fc ,
Y _fd, Y _bb , Y _bc , and Y _bd are obtained and stored in the third memory 113.

With respect to the Y-direction position of the grinding line 13a of the bevel grinding wheel 13 at the reference height ΔD, the position of the contact on the front side of the edge is ΔD / tanε ₁ , and the position of the contact on the rear side of the edge is ΔD / tanε ₂ .

The Y coordinate memory value Y _fi when the front contact is measured is calculated as χD / tan
Moving only epsilon _1, the front contact comes on grinding line 13a of the grindstone 13. The edge thickness W at this time is: W _i = [(χD / tanε ₁ ) + (χD / tanε ₂ )] − | Y _fi −Y _bi |
Becomes

Here, if the bevel position of the solid line is attached to the position of q: S of the edge thickness, the movement amount in the Y direction at that time is: Is required.

Center of the bevel spherical surface including the machining point P _i is the optical axis of the lens to be processed is attached eccentrically to the lens axis of the carriage, not located on the rotation axis of the lens axis, Therefore, the lens axis of the lens L The amount of deviation of the center of curvature of the bevel sphere in the three-dimensional coordinate axes (X, Y, Z) corresponding to 22a and 22b
Let A, B, and C be the radius of curvature Re of the bevel sphere. Becomes

Therefore, the deviation amounts A, B, C and the curvature radius Re are determined by the machining angle ▲
▼ and machining radius, at least 4 template radius using _i Machining point P _a corresponding _{to, P b, P c, P} d in the Y-direction movement amount _{y a, y b, y c} ,
y _d is obtained by equation (6), and the obtained _ya , y _b , y _c , and y _d are substituted and the above equation (7) is applied to determine y _d . Any template radial The radius vector stored in the second memory 112 for the machining point P _i corresponding to Movement amount y _i from the machining radius vector length data _{(i, i)} for the
A, B, C, and Re can be obtained from equation (7) after being determined. In the embodiment shown in FIG. 1, the curve input device 121 can be used to input the bevel position ratio q: S, and when the user inputs the bevel curve value Ce using this input device 121, the arithmetic unit 1
06 is (Where n is the refractive index of the lens, usually n = 1.525) is used to calculate Re, and the value of Re is substituted into the above equation (7), and the amount of movement y _{i in} the Y-axis direction of the lens based on an arbitrary bevel curve value Ce Can be requested.

The determined amount of movement y _{i in} the Y-axis during beveling of the lens
Is the template radius Corresponding to the fourth memory 114 Address and store the Y-axis direction movement data Becomes

Step 15 When processing the beveled grindstone, the control circuit 108 outputs the Y-axis direction movement amount data from the fourth memory 114. To control the motor 21 and motor 32 by using Is controlled on the X-axis so that the carriage 20 comes to the position of _yi . Thereby, a bevel vertex can be formed at the position of the specified ratio q: S over the entire edge of the lens. Further, when the bevel curve value Ce is given, processing is performed so that the bevel apex of the entire circumference is located on the bevel curved surface having the curve.

In step 14, the four template radials are assumed assuming that the lens L is eccentrically attached to the lens axis of the carriage. 降下 D _a , χD _b , χD _c , and χD _d are obtained based on the following formula, and the Y-axis direction movement amount y _i is obtained by using the equations (6) and (7). If L is guaranteed to be attached to the lens axis without any eccentricity,
Since the displacement amounts A, B, and C in equation (7) are all zero, one template plate radius Lens drop χD movement amount obtained from _a y _a a machining radius ▲ ▼ and the curvature radius Re of the working angle ▲ ▼ only bevel spherical surface can be determined based on, with a first (7) after the curvature radius Re determined Any template radial The movement amount y _i in the Y-axis direction based on Can be obtained by using the processing radial length data (▲ ▼, ▲ ▼) for.

<Second Embodiment> The first embodiment described above uses the method of detecting the Y-direction movement amounts Y _fi and Y _bi of the lens when the edge of the lens comes into contact with the beveled grindstone at the predetermined reference height ΔD. However, the following method can be adopted.

As shown in FIG. 8 (C), the height ΔD _i when the lens L or one of the grinding surfaces 13a or 13b of the beveling grindstone 13 is abutted is measured, and then the lens L is set in advance. The lens L is moved by the distance ΔY in the Y-axis direction, and the contact height χD _i ′ of the lens L at that time is measured. From the magnitude relationship between the measured heights ΔD _i and ΔD _i ′, it is determined which of the ground surfaces 13a and 13b the lens L has now contacted. In the example of FIG.
Since D _i > χD _i ′ and Y _fi <Y _fi ′, it is determined that the front edge of the lens L is in contact with the front ground surface 13a. Next, the lens L is moved by a predetermined distance d so that the rear edge of the lens L can contact the rear ground surface 13b. The height χD _i ″ at this time is measured. Hereinafter, from the measured χD _i , χD _i ″ and Y _fi , Y _fi ″, the above (5),
(6) can be determined the Y-direction moving amount Y _i on the basis of the equation.

In the embodiment described above, the template T is held by the lens shaft 22b, and the abutment of the template T is detected by the mold receiving base 38 to determine the inter-axis distance l _i. The cost increase due to the special provision of the measuring means is avoided.
However, the present invention is not limited to this embodiment, and a configuration is provided in which a set of measuring means having the same configuration as that of the mold cradle 38 is provided separately from the mold cradle to measure the distance between the axes, and the vicinity thereof is It is needless to say that the inter-axis distance measuring means may be dedicated by a method in which a rotating shaft for holding a template is provided.

In addition, it can be set so that the ratio of the edge of the bevel to the edge thickness is determined according to the material of the frame. In other words, a curve input device 121 for inputting an arbitrary bevel curve value is further provided with a selection switch of a material of a frame in which a lens to be processed is framed, for example, a selection switch of “cell frame” and “metal frame”, and “cell frame” and If you have a built-in memory that stores in advance the edge thickness ratio of the bevel according to the “metal frame”, if the user operates the selection switch and selects “cell frame” or “metal frame”, The ratio position stored in the memory is automatically read, and (6)
Equations (7) and (7) are calculated by the arithmetic circuit 106, and the Y-direction movement amount data suitable for the frame material May be automatically calculated.

In the above-described embodiment, the processing radial information (from the template)
_i , _i ) were obtained, but the present invention is not limited to this, and as disclosed in Japanese Patent Application No. 58-225197 and Japanese Patent Application No. 60-115080, the shape of the lens frame of the spectacle frame was changed. It goes without saying that the present invention can also be applied to a so-called non-former type ball mill which measures directly.

(Effects of the Invention) As described above, according to the present invention, it is possible to eliminate the processing deviation of the bevel apex position as in the related art, and to set the edge around the lens in advance or arbitrarily. Lens grinding method and apparatus capable of forming a bevel apex along a ratio position and a bevel curve value.
In addition, the measurement of the lens edge thickness and the beveling control based thereon can be accurately performed without specially providing a large-scale device dedicated to measuring the lens edge thickness as in the conventional lens edge thickness measuring method and the apparatus therefor. This has the effect of being less susceptible to the effects of grinding pieces and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a lens grinding apparatus according to the present invention, FIG. 2 is a flowchart for explaining the operation thereof, FIG. 3 is a schematic diagram showing a method for obtaining the center distance, FIG. The figure is a schematic diagram showing a method of obtaining machining radius data, FIG. 6 is a schematic diagram showing a relationship between a lens rotation angle, a machining radius length and a machining angle, and FIGS. 7 (A), (B) and (C). ) Is a schematic diagram showing a method for measuring the amount of lens descent, FIGS. 8 (A), (B), and (C) are schematic diagrams showing a method for obtaining the amount of movement in the Y-axis direction. FIG. 11 is a schematic diagram showing the relationship between the diameter of the lens and the lateral movement, FIG. 11 is a diagram showing the relationship between the grindstone and the processing point of the lens, and FIG. 12 is a diagram showing the processing state of the bevel. 12… Rough whetstone 13… Bevel whetstone 22a, 22b… Lens axis 25,32,37… Motor 38… Type pedestal 301… Counter 302… Control circuit 106… Operation circuit 108… Control circuit 110 …… Memory

Continuation of the front page (72) Inventor Takahiro Watanabe 75-1 Hasunumacho, Itabashi-ku, Tokyo Tokyo Optical Machinery Co., Ltd. (72) Inventor Yasuo Suzuki 75-1 Hasunumacho, Itabashi-ku Tokyo, Tokyo Optical Machinery Co., Ltd. (56) References JP-A-61-156022 (JP, A) JP-A-60-160164 (JP, A) JP-A-60-118461 (JP, A) JP-A-59-156657 (JP, A) 1988-196364 (JP, A)

Claims (4)

(57) [Claims] 1. Processing radial information (▲ ▼,
▲ ▼) is the radius A first stage to be determined in correspondence with the above, and a lens descending amount (χD _i ) and an axial moving amount of the lens fixed shaft when the front and rear edges of the rough-ground workpiece come into contact with the beveled grindstone. (Y _fi , Y _bi ) Based on the second step obtained in association with the above and the processing radius information (（, ▼), the lens descent amount (χD _i ), and the axial movement amount (Y _fi , Y _bi ), The above radial radius when beveling the processed lens To find the amount (y _i ) of moving the lens axis corresponding to
And the radial movement of the template during beveling of the lens to be processed. Moving the lens to be processed in the axial direction of the lens by the amount of movement (y _i ) in the axial direction in accordance with the following formula, and performing beveling. 2. The lens grinding method according to claim 1, wherein said lens descent amount (χD _i ) is a predetermined amount. 3. A pair of coaxially rotatable lens axes capable of holding a lens to be processed, a rough grindstone for rough grinding of the lens to be processed, and a bevel for beveling an edge surface of the lens to be processed. In a lens grinding device with a whetstone, the processing radius information (▲ ▼, ▲ ▼) of the lens to be processed is Means for determining in correspondence with the above, and the respective lens descending amounts (χD _i ) and the axial movement of the lens axis when the front and rear edges of the lens roughly ground by the rough grinding wheel abut against the beveled grinding wheel. Quantity (Y _fi , Y
_bi ) the radial Based on the processing radius information (▲, ▼), the lens descent amount (χD _i ), and the axial movement amount (Y _fi , Y _bi ). The above radius when beveling Means for determining the amount (y _i ) of moving the lens axis corresponding to the following; Means for moving the lens to be processed in the axial direction of the lens axis by the amount of movement in the axial direction (y _i ) in accordance with the following. 4. The lens grinding apparatus according to claim 3, wherein said lens descent amount (χD _i ) is a predetermined amount.