JPH0818235B2 - Lens radius measuring device for lens edge processing machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lens edge processing machine capable of automatically attaching a bevel to the edge of an eyeglass lens, and more particularly to accurately measuring a mold plate radius. The present invention relates to a template radius measuring device. Note that the above-mentioned bevel includes not only the convex portion formed on the peripheral edge of the lens for forming a frame, but also a groove in the case of forming a groove on the peripheral edge of the lens.

(Prior art) When forming a bevel on the periphery of a spectacle lens that has undergone rough shaving, in order to match the bevel to the curve of the spectacle frame, rotate the spectacle lens and adjust the radius position that is being ground by the bevel grindstone. The bevel is formed by controlling the position of the spectacle lens in the axial direction by a certain amount.

In that case, it is ideal to form a bevel at the peripheral position of the spectacle lens through which this spherical surface passes when imaginarily overlapping the spherical surface determined by the curve value of the spectacle frame on the spectacle lens. If formed, the bevel rides completely on the spherical surface, no unnatural force acts between the spectacle lens and the spectacle frame, and the spectacle lens fits neatly into the spectacle frame.

However, if the curve value of the spectacle frame is treated as it is, it will be complicated and impractical. Therefore, as shown in FIG. 1 of JP-A-58-177256,
The tangent line on the radius R corresponding to the curve value of the spectacle frame and at the position of the average value rmean of the radius r of the spectacle lens is defined as an approximate profile line, and based on this approximate profile line, the axial direction of the bevel with respect to the radius of the spectacle lens Even if the amount of movement is calculated, it is sufficiently practical.

By the way, in the conventional device of this type, the radius of the spectacle lens is obtained based on the template. That is, a template is fixedly mounted on the lens rotation shaft that holds the spectacle lens, and the template is brought into contact with the mold receiving surface having the same curvature as the grindstone by the weight of the head frame (to be precise, rough sliding is the template. The spectacle lens is ground until it comes into contact with the mold receiving surface), and the mold plate is rotated by the rotation of the lens rotation axis, and the rotation angle of the lens rotation axis is calculated from the displacement of the head frame relative to the rotation angle of the lens rotation axis. Seeking the radius of the eyeglass lens for.

(Problems to be Solved by the Invention) In the prior art as described above, when it is attempted to process points other than the inflection point of the spectacle lens, since the grindstone has a finite diameter, it is not actually the vertex of the grindstone. , Processed at a certain distance.

Therefore, when measuring the radius of the spectacle lens, the contact point B between the template 1 and the mold receiving surface 2 corresponds to the processing point of the spectacle lens, as shown in FIG. Distance r between the center O _{1 of the} template 1 (which coincides with the center of the lens rotation axis) and the contact B
Is the true radius at the processing point in FIG. However, the amount of rise of the head frame, which is determined by the contact of the mold plate 1 with the mold receiving surface 2, is the center O ₁ of the mold plate 1 and the center of curvature O of the mold receiving surface 2 (this coincides with the rotation center of the grindstone 3). Depends on the distance r ′ between the center O ₁ of the template 1 and the point A where the edge connecting the two intersects with the die receiving surface 2.

In other words, if the contact point B corresponding to the processing point is separated from the contact point A (this amount is indicated by d in FIG. 6), the measured radius will be different from the true radius.

Therefore, as shown in FIG. 7, the shape of the template reproduced from the radius data measured by one rotation of the lens rotation axis is different from the actual shape of the template (shown by the solid line) (broken line). Will be shown). In FIG. 6, the point where the shape of the template obtained by the measurement and the shape of the actual template are the same is because the radius here is because the normal line here passes through the center O of the template. It is a point that can be measured accurately.

Therefore, in the conventional device, the amount of change in the lateral movement is based on the inaccurate radius r ′, so that the bevel actually formed on the peripheral edge of the spectacle lens is not smooth, that is, the bevel of the spectacle frame. If the bevel curve is not along the rim curve, especially in the case of a specially shaped target lens these days, if the frame is forced, the lens will locally concentrate stress on the rim, and with glass lenses It has the drawback that it is fragile and plastic lenses cause distortion.

Therefore, an object of the present invention is to obtain a mold plate radius measuring device for a lens edge processing machine, which can obtain an accurate radius of the mold plate.

(Means for Solving Problems) The present invention provides a lens rotation shaft (51, 52) for holding a spectacle lens (50) and a template (1), and a bevel on the periphery of the lens. A grindstone (18) and a mold receiver (19 ') that is in contact with the mold plate and has a curved surface with the same curvature as the grindstone;
A displacement measuring device (45, 14, 44) for measuring the amount of displacement of the lens rotation shaft (51, 52) in the radial direction from the relative movement between the template and the mold receiver; Equipment (45,
14, 44) controls the axial position of the eyeglass lens (50) with respect to the grindstone (18) based on the displacement amount measured by
In a lens peripheral edge processing machine configured to form a bevel on the peripheral edge of an eyeglass lens (50), a storage unit (17, 46, for storing a measurement value dependent on the displacement amount for each predetermined rotation angle of the lens rotation axis. 58, 18) and a conversion means (17) for converting each of the measured values stored in the storage means from a plurality of measured values into a template radius at the time of beveling. It is a plate radius measuring device.

[Work]

In the present invention, a plurality of measured values are added to the measured values depending on the amount of displacement of the predetermined rotation angle and a substantially accurate radius is calculated by analogy, and the displacement of the lateral movement of the spectacle lens with respect to the grindstone is almost the same. It is obtained accurately and the bevel becomes smooth.

(Embodiment) FIG. 1 is a perspective view of a lens peripheral edge processing machine in which an embodiment of the present invention is used, and FIG. 2 corresponds to the rear view of FIG. 1, and a portion related to horizontal movement of a head frame will be described. FIG. 3 is a block diagram of a control system used together with FIG. 1 and FIG. 2, and FIG. 4 is a flowchart of the control device of FIG.

In FIG. 1, a support bearing fixed to the body frame 10
A support shaft 30 is supported on 20 and a head frame 40 is attached to the support shaft 30 so as to be rotatable (arrow A) and horizontally movable in the axial direction (arrow B). A recess for chucking the spectacle lens 50 is formed in the head frame 40, and the lens pressing shaft 51 and the lens receiving shaft 52 are penetrated into the recess from both sides of the head frame 40, and one end of the lens pressing shaft 51 is formed. A driving device 53 such as a motor for driving the shaft 51 in the axial direction is connected to the above, and the other end is provided with rubber or the like for directly pressing the spectacle lens 50, which is not shown in the drawing.

On the other hand, at one end of the lens receiving shaft 52, a template 1 having a rim-shaped spectacle frame is attached by being pressed in the axial direction of the lens receiving shaft 52 by a pressing member 54. The contact member of the pressing member 54 with the mold plate 1 is rotatable with respect to the main body of the pressing member 54 so that the mold plate 1 rotates together with the lens receiving shaft 52. A reference plate 55 having a notch indicating a reference position is fixed to the lens receiving shaft 52, and the head frame 40 is provided with a sensor 56 for reading the notch of the reference plate 55.

Lens pressing shaft 51 and lens receiving shaft 52 (hereinafter referred to as lens rotation shaft)
51 and 52) are rotated by a lens rotation pulse motor 43 via a transmission device such as a gear train 41 and a belt 42.

Therefore, for each revolution of the lens rotation shafts 51 and 52, the sensor 56
From which the reference signal will be obtained.

As shown in FIG. 2, the body frame 10 has a support shaft 30.
A timing belt 11 is provided so as to move in the axial direction of, and the timing belt 11 is moved by a motor 12. The timing belt 11 is provided with a connecting member 13 that moves along the support shaft 30. The head frame 40 and the connecting member 13 are integrated with each other in the axial direction of the support shaft 30, and the head frame 40 can be rotated by sliding on the contact surface with the connecting member 13. As a result, the support shaft 30 of the connecting member 13
By moving the head frame 40 in the axial direction,
Move in the 30 axis direction (horizontal direction B). Further, the rotation of the head frame 40 around the support shaft 30 is not hindered by the connecting member 13.

A wire 14 is fixed to the connecting member 13 at one end thereof, and the other end of the wire 14 is fixed to a pulley 45 fixed to a rotation shaft of a rotation detecting encoder 44 fixed to the head frame 40. Therefore, the rotation angle of the head frame 40 around the support shaft 30, that is, the vertical position of the head frame 40 can be detected from the output signal of the encoder 44. The encoder 44 may be an absolute encoder that outputs the absolute amount of the vertical position of the head frame 40, or an incremental encoder that outputs a reference signal at the fully raised reference position of the head frame 40.

Further, the main body frame 10 is provided with a grindstone 18 and a vertical movement device 19 for the template 1. A member 19 'of the vertical movement device 19 is a die receiver on which the template 1 is placed, and has the same curvature as the grindstone 18.

In FIG. 3, a head frame horizontal moving device 15 includes a timing belt 11, a motor 12, and a connecting member 13, and supports a head frame 40 according to a drive signal from a control device.
Move horizontally along 30. The head frame horizontal position detection device 16 includes an encoder (not shown), and specifically, a rotary encoder that detects the rotation angle of the motor 12 can be used. When a pulse motor is used as the motor, the horizontal position of the head frame 40 can be detected by counting the number of pulses applied to the motor 12.

The head frame vertical position detection device 47 includes the wire 14 and the encoder 44, and outputs a detection signal of the vertical position of the head frame 40.

The lens rotation shaft drive device 46 includes a gear train 41, a transmission device such as a belt 42, and a pulse motor 43, and lens rotation shafts 51 and 52.
To rotate. Rotation initial position detector for lens rotation axes 51 and 52
Reference numeral 57 includes a reference plate 52 and a sensor 56, and outputs a lens rotation initial position signal.

The mold plate rotation angle detection device 58 may directly measure the rotation angles of the lens rotation shafts 51 and 52 by an encoder or the like (not shown), but as described above, the lens rotation shaft drive device 46 uses the pulse motor. When is used, the rotation angles of the lens rotation shafts 51 and 52 can be detected by counting the number of pulses applied to the pulse motor.

The control device 17 includes a head frame horizontal position detection device 16,
The signals from the head frame vertical position detector 47, the lens rotation axis initial position detector 57, and the template rotation angle detector 58 are input, and a control signal is sent to the head frame horizontal movement device 15 and the lens rotation axis drive device 46. Enter. Also, the control device
A storage device 18 for storing data is stored in 17.

The procedure for measuring the mold plate radius will be described below with reference to FIG. 4 which is a flowchart of the control device 17.

The control device 17 determines whether or not the rough sliding of the unprocessed eyeglass lens is finished (step 170). If the rough sliding is finished, the control device 17 causes the lens rotation shaft drive device 46 to set the initial rotation position of the lens rotation shaft. The drive signal (pulse) is output until the initial position signal is obtained from the detector 57 (step 171). Then, the drive signal is output to the lens rotation shaft drive device 46 again so as to rotate the lens rotation shafts 51 and 52 by a predetermined angle θ (for example, 1 degree) (step 172). Then, the vertical position of the head frame 40 at that time is input from the head frame vertical position detection device 47 (step 173) to obtain the measurement radius of the template, and the rotation angle of the template from the rotation angle detection device 58 of the template. To the storage device 18 (step 174). step 1
When 74 ends, the process returns to step 172 again, the lens rotation shafts 51 and 52 are rotated again by a predetermined angle θ, and steps 173 and 174 are performed. Then, the lens rotation shafts 51 and 52 rotate once (360
Degree), that is, when the measurement and storage of the entire circumference of the template 1 are completed (step 175), calculation is performed from the measured radius data stored in the storage device 18 in correspondence with the angle, and the true value is obtained for each degree. The radius is calculated (step 176).

This calculation is based on the following principle. That is, in order to make it easy to think that the mold plate 1 is rotated with respect to the mold plate 19 ', the state in which the mold plate 19' is rotated with respect to the mold plate 1 is shown in FIG. However, as shown in FIG. 5, the controller 17 first detects the rotation angle of the template 58.
To the radius r ′ _(n) of the template measured at each angle θ by
The radius l of the die receiver 19 '(the same radius as the grindstone 18 and die die 19') is added to the value l _n , and the same value is also obtained for the measured values of the angles on both sides thereof l _(n-1) And l _{(n + 1)} .

By the way, the bending axial center O _{(n + 1)} and O
Mold holder 1 at the position to be measured so that it is perpendicular to the line connecting _(n-1)
A line is drawn from the center of curvature O _{(n) of} 9 ', and the point B _n intersecting the circle of radius R centered on O _(n) is the position where the true template radius is to be obtained (measurement radius r' _{(n )} ) Is the processing point. If the distance from the center O ′ of the template 1 to the processing point B _n at that time is f _(n) , f _(n) is an almost accurate radius at the position where the true template radius is to be obtained. However, O _(n) is O _{(n + 1)} and O _{(n + 1)
The} error increases as the distance from the line connecting _(n-1) increases. However, if the measurement angle θ is reduced, the error decreases to such an extent that there is no practical problem.

To find the true radius f _(n) , it is necessary to find the angle α between O ', O _(n) and _Bn . This angle α is the line connecting _O'and O _(n) from the point O _(n-1). Orthogonal to Equal to the angle between.

Therefore, Than And α is obtained.

So, by the second law of cosine of triangle, Is required.

The true radius f _(n) thus obtained is stored again in the storage device 18 in correspondence with the angle (step 177).

These things, Motomari f _(n) is for each l _(n) be performed over the entire circumference, substantially precise radius is obtained (step 178). Of course, as described above, the smaller θ is, the closer the radius becomes to the correct radius.

Determining the axial position for bevel formation based on the template radius data obtained in this way is exactly the same as the prior art (Japanese Patent Laid-Open No. 177256/1983) shown above. , Description is omitted.

In the above explanation, the true radius was calculated from the measured value, but since many complicated calculations require time,
By creating a correspondence table in advance, it is possible to find the true radius by fitting. That is, based on a certain value, measure the true radius of a certain value from various combinations that can occur before and after that, and search for a combination that fits a certain measured value and the values before and after that, and then find the corresponding combination. The true radius indicated by is the true radius of a measured value. According to this method, the calculation time can be shortened. Further, in the template rotation angle detection device 58 of FIG. 3, the control device 17 itself can predict the rotation angles of the lens rotation shafts 51 and 52 by the pulse for controlling the output pulse motor to the lens rotation shaft drive device 46. Therefore, the control device 17 can also function as the template rotation angle detection device 58.

〔The invention's effect〕

As described above, in the present invention, since the correct radius of the template is obtained, the lateral movement amount based on it is smooth, that is,
Since the bevel is also smooth, there is an effect that it is easy to put it in the spectacle frame.

[Brief description of drawings]

FIG. 1 is a perspective view of a lens peripheral edge processing machine used in an embodiment of the present invention, and FIG. 2 is a rear view of FIG. 1, and is a simplified view for explaining a portion related to horizontal movement of a head frame. FIG. 3 is a block diagram of a control system used together with FIGS. 1 and 2, FIG. 4 is a flow chart of the control device of FIG. 3, and FIG. 5 is for explaining the principle of the present invention. 6 and 6 are views for explaining the relationship between the conventional template and the mold receiver, and FIG. 7 is a diagram showing the relationship between the conventional measured template and the actual template. [Explanation of symbols of main parts] 1 ... template, 17 ... control device, 18 ... storage device, 46 ... lens rotation axis drive device, 51, 52 ... lens rotation axis, 58 ... template Rotation angle detection device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Izumi Umemura 471 Nagaodai-cho, Sakae-ku, Yokohama-shi, Kanagawa Nihon Kogaku Kogyo Co., Ltd. Yokohama Works (56) Reference JP-A-62-292353 (JP, A)

Claims (1)

[Claims] 1. A lens rotation shaft for holding a spectacle lens and a template, a grindstone for forming a bevel on the peripheral edge of the lens, and the template contacted to each other and having a curved surface having the same curvature as the grindstone. A mold receiver, and a displacement measuring device that measures the amount of displacement in the radial direction of the lens rotation axis from the relative movement of the mold plate and the mold receiver, and the displacement amount measured by the displacement measuring device. A lens edge processing machine configured to control the axial position of the eyeglass lens with respect to the grindstone based on the lens edge processing machine so as to form a bevel on the edge of the eyeglass lens, in the displacement amount for each predetermined rotation angle of the lens rotation axis. Storage means for storing dependent measurement values, and conversion means for converting each of the measurement values stored in the storage means from a plurality of measurement values to the template radius at the time of beveling Template Radius measuring device.