KR101341236B1 - Method for calibrating an ophthalmic lens machining tool, and machining tool for implementing same - Google Patents

Abstract

The present invention relates to a spectacle lens processing tool comprising a fixed frame, a row of rotary grinding wheels 5, a lens holder 9, and a pair of driven parts 20A, 20B. The adjustment method includes a step of determining the position of the axis X0 of the follower 20A, 20B, which step has a known predetermined shape and is pre-mounted to the holder 20A. , 20B), controlling the template and measuring the corresponding movement of the followers 20A, 20B, and thereby deriving the position of the axis X0 of the follower.

Description

METHOD FOR CALIBRATING AN OPHTHALMIC LENS MACHINING TOOL, AND MACHINING TOOL FOR IMPLEMENTING SAME

The present invention relates to a method for adjusting a spectacle lens processing tool, the processing tool,

-Fixed frame;

A row of grinding wheels mounted to rotate about a fixed frame about the first axis;

A support of the spectacle lens, comprising means for rotationally driving the lens about a second axis that is movable relative to the stationary frame and substantially parallel to the first axis;

An apparatus for controlling the support and the drive means; And

Substantially parallel to the first axis and movable parallel to the frame along the same axis, provided to contact each other and to measure its axial position with each of the two sides of the lens and to be axially pressed against each other It includes a pair of sensors.

Sensors that can standardize the measurement of the exact position of the front and rear surfaces of the lens (or glass) are needed for accurate positioning of the inclined plane, grooves, reverse inclined planes and holes. For example, for accurate fabrication of so-called "half-and-half" slopes, it is necessary to accurately form the top of the slopes at the same distance from the front and rear of the glass on the peripheral edge of the glass.

In general, in known grinding machines, the position of the fixed sensor axis relative to the frame is known only with inaccuracies of one millimeter order. Due to this inaccuracy, the rough positioning of the above-described machining type is generated.

The object of the present invention is to overcome these disadvantages and to improve the precision of the spectacle lens processing tool.

To this end, the present invention relates to a method for adjusting a tool of the type described above, comprising a method for positioning the axis of a sensor, the adjustment method comprising:

Bringing a template between the sensors so that the sensor contacts each side of the template, the template having a predetermined shape whose contour is known and premounted on the support;

Controlling the movement of the template relative to the sensor and measuring the corresponding movement of the sensor;

Deriving therefrom information about the position of the axis of the sensor.

According to another feature of the method according to the invention,

With the support mounted to pivot relative to the frame, firstly the basic steps are carried out with a first template having a contour that is partly straight, the first template having a straight portion of its contour with the pivot axis of the support relative to the frame. Mounted on the support and positioned around the second axis so as to be coplanar and orthogonal to its pivot axis, after which the support passes through a rotational axis of the support and measures the plane in which the axis of the sensor is located A zero distance indicating this passage is pivoted to move the template between the sensors to a position detected between the sensors;

Secondly, the basic steps are carried out with a template in which a portion is angled and forms an end, the template being rotated and the rotation of the support about its pivot axis to move the tip in the plane measured during the first execution of the basic steps. It is moved by a compound rotation of the rotation of the template about two axes, and the position of the axis of the sensor on this plane is estimated from the corresponding movement of the sensor;

A single template is used for the first and second executions of the basic step, the single template having a contour in which the first part is straight and the second part is angled and forms an end;

The method of axializing the sensor comprises the step of producing a template, wherein the spectacle lens is processed in the machining tool according to the predetermined shape of the template before the basic step is carried out, the template consisting of the manufactured spectacle lens;

The sensor has an end forming a part in contact with the lens, the adjustment method comprising a method of checking the state of the contact,

Taking a template with a known shape and having a contour pre-mounted on the support, between the sensors such that the sensors contact each side of the template;

Controlling the movement of the template relative to the sensor and measuring the corresponding movement of the sensor;

Deriving therefrom information on the shape of the contact.

The invention also relates to a spectacle lens processing tool suitable for carrying out the method as described above.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic perspective view of a machining tool suitable for carrying out the method according to the invention.

FIG. 2 is an enlarged view of the detail of FIG. 1 showing a grinding wheel, a lens and a sensor. FIG.

3 is a schematic diagram showing a first step of the method according to the invention.

4 and 5 are schematic diagrams illustrating a second step of the method according to the invention.

1 and 2 show a spectacle glass processing tool of the type suitable for implementing the adjustment method according to the invention.

This tool 1 comprises a frame 3 which is assumed to be fixed and to which fixed coordinate systems O, X, Y and Z are attached.

In this coordinate system, the X and Y axes form a plane that is assumed to be horizontal, and the Z axis represents an upward vertical axis.

The tool 1 also comprises a row of grinding wheels 5 mounted to rotate on the frame 3 about a _first axis of rotation x ₁ parallel to the X axis. The rows of grinding wheels 5 are rotationally driven by a grinding motor (not shown).

The tool 1 also comprises a support 7 of the spectacle lens 9.

The support (or carriage) 7 has means for rotationally driving the lens 9 about a second axis x ₂ associated with the support 7 and substantially parallel to the first axis x ₁ . It is provided.

The drive means comprise in particular two coaxial half shafts 11A, 11B and a drive motor 13 suitable for holding the lens 9 (or lens blank) therebetween. The motor 13 has an output shaft connected to the half shaft 11B, and rotates and drives the lens 9 about the axis x ₂ by the half shafts 11A and 11B.

The support 7 itself is also mounted to pivot about the frame 3 about a third axis x ₃ parallel to the axis X.

For this purpose, the tool 1 comprises a motor 15 for turning the support (7) about the axis (x ₃₎ with respect to the frame (3). The motor 15 drives the support body 7 by a transmission mechanism that will not be described herein.

The tool 1 also includes a device 19 for controlling the motors 13, 15 connected to the control device 19. This device 19 is centered on the axis x ₂ and the movement of the support 7 relative to the frame 3 in order to control the movement of the lens 9 with respect to the grinding wheel 5 in a controlled manner. It is suitable for controlling the rotation of the lens 9 with respect to the support 7.

In addition, the tool 1 comprises a pair of sensors schematically shown in the form of arrows in FIG. 1 with reference numerals 20A, 20B.

The sensor is mounted to slide coaxially with respect to the frame 3 in the X direction, and each of the sensors 20A, 20B is fixed relative to the frame 3 and slides on rods 21A, 21B parallel to the X axis. Is mounted.

Each sensor 20A, 20B includes a free end 23 that forms a contact and has a semi-circular shape (shown schematically in FIG. 5) in a substantially horizontal plane. The contacts 23 of the two sensors 20A, 20B rotate towards each other, and the sensors are positioned and provided so as to contact each of the two faces of the spectacle lens being ground. The contact between the sensors 20A, 20B and each lens face is quasi-punctiform.

The sensors 20A, 20B are associated with return means (not shown) which press the sensors towards each other, ie, when the lens 9 is engaged between the sensors, into a contact position with the lens 9. .

The axis x ₀ of the sensor, defined by a line passing through the contact 23 (ie passing through the contact point when the lens is engaged between the sensors), is parallel to the horizontal axis X.

In the method of adjusting the tool 1 as provided in the present invention, the method of determining the axes x ₀ of the sensors 20A and 20B is carried out in coordinate systems O, X, Y and Z fixed with respect to the frame 3. do.

In the first step of the method of positioning the axis x ₀ , the spectacle lens 29 whose contour is of a predetermined shape is machined in the tool 1.

The first position 31 of the contour of the spectacle lens 29 to be used as a template is a straight line, and the second position 32 is at an angle and forms an end at one end of the straight portion 31. The angled portion 32 defines an angle that is less than 180 degrees, preferably less than 90 degrees, and most preferably less than 45 degrees.

In the example shown, the spectacle lens 29 forming the template has a generally triangular shape having a right angle 33 of the other end of the straight portion 31 and a curved portion 24 opposite the straight portion 31. Has

Lens 29 has a peripheral edge of thickness substantially greater than zero.

Figure 3 shows the rotation axis (x ₃₎ of the support about the rotation axis (x ₂₎ and the frame (3) of the lens (29) to the support (7). These axes x _2, x ₃ are perpendicular to the plane of the drawing.

After the step of machining the lens 29 forming the template, the center of rotation of the support 7 in the center plane of the lens 29 (in the drawing, with the lens 29 still mounted on the support 7). The lens 29 is positioned around the axis of rotation x ₂ to align the axis x ₃ ) with the straight portion 31. In other words, the lens 29 is positioned so that the straight portion 31 is located coplanar with the axis x ₃ and perpendicular to this axis.

After arranging the lens forming the template 29 between the sensors 20A and 20B such that the sensors 20A and 20B contact the front and rear surfaces of the lens 29, respectively, the support 7 is a straight portion 31. From the direction toward the rotation center of the lens 29 corresponding to the axis x ₂ from the rotation direction about the axis x ₃ , in the direction indicated by the arrow F in FIG. 3.

A pivot about its axis x ₃ of the support 7 causes the sensor to form a lens 29 that forms a template 29 to a position where the sensor detects a zero thickness indicating that the straight portion 31 has passed. It is controlled by the device 19 so as to move between 20A and 20B, after which the contact portion 23 of the sensor falls into the gap. Thus, in the straight portion 31, a transition occurs from a state in which a distance corresponding to the thickness of the lens 29 is detected between the sensors 20A and 20B to a state in which a zero distance is detected between the sensors.

Since the movement of the sensors 20A, 20B is measured in real time during the movement of the lens 29, the passage of the straight portion 31 is detected in the region of the axis x ₀ of the sensor.

In practice, this step is carried out step by step while measuring the intervals of the sensors 20A and 20B in each step. In each step, the sensors move away from the template 29, the support 7 pivots by the base angle, the sensors are pressed towards each other, and the distance separating the sensors is measured.

In this case, the position of the linear portion defines the plane P on which the axis x _{0 of the} sensor is located along with the axis x ₃ .

In the next step of the method of determining the axis x ₀ (this step is shown in FIG. 4), the lens 29 engages again between the sensors 20A, 20B in the region of the end 32. The end 32 of the lens forming the template 29 is a compound rotation of the rotation of the support 7 about the axis x ₃ and the rotation of the lens 29 about the axis x ₂ . Is arranged on the measured plane P.

This compound rotation is operated and controlled by the control device 19, and the movement of the sensors 20A and 20B is recorded at each measurement position.

FIG. 5 shows the end 32 of the lens forming the template 29 at three consecutive measurement positions with respect to the sensors 20A and 20B during the arrangement on the plane P previously identified.

The tip 32 is in the form of a segment extending substantially in the thickness direction of the lens forming the template 29.

Since the contact portion 23 of the sensor has a semicircular shape in the plane of movement, the movement of the tip 32 between the sensors causes the movement of the sensor along its axis x ₀ .

The maximum spacing of the segments 23 occurs when the segment with the thickness corresponding to the tip 32 is aligned with the axis x ₀ of the sensor.

During this step of the method of determining the axis x ₀ , the measurement of the movement of the sensor on the plane P (eg at approximately eight different positions at the end) of the axis x ₀ corresponds to the maximum spacing of the sensors. Leads to an accurate estimation of the position. This situation is shown in the center part of FIG.

In a similar manner, in order to check the shape of the contact portion 23, it is possible to carry out a step consisting of placing the tip 32 between the sensors 20A, 20B on the plane P and measuring the movement of the sensor. Will understand. Since the shape of the lens forming the template 29 is well known, and the position of the sensor axis x ₀ has been identified, the contact portion 23 is measured by measuring the movement of the sensor as the tip 32 passes. It will be appreciated that it is possible to estimate information about the shape of the.

Thus, it is possible to detect wear or break of the contact portion 23 of the sensor in order to carry out the movement or repair.

Thus, the adjustment method according to the present invention may include, in addition to the method of positioning the axis of the sensor, a method of confirming the state of the contact portion in a similar basic step.

It will be appreciated that a method of positioning the axis of the sensor may be practiced using an optionally reusable template that may be prefabricated and made of a different material than the spectacle lens. Such a template whose shape is exactly known and recorded in the control device is precisely disposed on the support 7 in the same manner, coupled between the sensors 20A and 20B, and may be moved according to the same steps as described above.

On the other hand, first use the straight portion 31 to find the plane P, then move the template using the end 32 to find the position of the axis x _{0 in} the plane P. It is also possible to carry out successive steps by different templates.

As described above, in order to carry out the first step (determination of plane P), any form of template having a straight portion of sufficient size is suitably provided.

As mentioned above, in order to carry out the second step (positioning on plane P), any form of template with an end defined at an angle small enough to provide acceptable precision is likewise appropriately provided.

By virtue of the above-described invention, while a template whose known shape is known moves in a controlled manner between the sensors, it is possible to measure substantially the movement of the sensor and to estimate the exact position of the axis of the sensor therefrom. It is possible to greatly improve the accuracy of the inclined surface, reverse inclined surface, groove or hole on the edge).

This improvement in tool precision is achieved without increasing the complexity of the mechanical parts and without substantially increasing the working time required to adjust the tool.

The function consisting of positioning the axis of the sensor allowing for an increase in precision is virtually inexpensive by the use of the method according to the invention.

Claims (7)

A fixed frame 3; A row of grinding wheels 5 mounted to rotate about the frame 3 about a first axis x ₁ ; - a support (7) for the spectacle lens (9), the frame (3) to be movable with respect, to the lens with respect to the first axis (x ₁₎ and substantially parallel to the second axis (x ₂₎ A support body 7 for the spectacle lens 9 having means for driving rotation 11A, 11B, 13; An apparatus (19) for controlling the support (7) and the drive means (11A, 11B, 13); And Movable in parallel with respect to the frame 3 along the same axis x ₀ substantially parallel to the first axis x ₁ , each in contact with each of the two sides of the lens 9; A method of adjusting a spectacle lens processing tool, comprising a pair of sensors 20A, 20B provided to measure its axial position and being axially pressed toward each other, A method of determining the position of the axis (x ₀ ) of the sensors (20A, 20B), This positioning method is A template 29 having a predetermined shape whose contour is known, and which is pre-mounted on the support 7, between the sensors 20A, 20B such that the sensor contacts each face of the template 29. Coming steps, Controlling the displacement of the template 29 relative to the sensors 20A, 20B and measuring the corresponding displacement of the sensor, A basic step consisting in deriving therefrom information relating to the position of the axis (x ₀ ) of the sensor (20A, 20B). The method according to claim 1, The support 7 is mounted to pivot with respect to the frame 3, and firstly, the basic steps are carried out with a first template 29 having a contour in which part 31 is straight, and the first The template 29 is mounted on the support 7, and the straight portion 31 of its contour is coplanar with the pivot axis x ₃ of the support 7 relative to the frame 3. And positioned about the second axis x ₂ to be perpendicular to the pivot axis x ₃ , after which it passes through the axis of rotation x ₃ of the support 7 and the sensors 20A, 20B. In order to determine the plane P at which the axis x ₀ is located, the template 29 is moved to a position where a zero distance indicating that the straight portion 31 has passed is detected between the sensors. , The support (7) is pivoted so as to move between the 20B). The method of claim 2, Secondly, the basic steps are carried out with a template 29 with a contour in which a part 32 is angled and forms a point, on a plane P determined during the first execution of the basic steps. The template 29 is caused by a combined rotation of the rotation of the support 7 around the pivot axis x ₃ and the rotation of the template 29 around the second axis x ₂ to move the tip 32. ) Moves, and the position of the axis (x ₀ ) of the sensors (20A, 20B) on this plane (P) is derived from the corresponding displacement of the sensor. The method of claim 3, A single template 29 is used for the first and second implementation of the basic steps, wherein the single template 29 ends with the first portion 31 straight and the second portion 32 angled. It has a contour to form, The adjustment method of the spectacle lens processing tool characterized by the above-mentioned. The method according to any one of claims 1 to 4, The method for determining the axis x ₀ of the sensors 20A, 20B comprises a step of manufacturing a template 29 in which the spectacle lens is processed in a machining tool according to the desired shape of the template before the basic steps are carried out. And the template (29) comprises a manufactured spectacle lens. The method according to any one of claims 1 to 4, The sensor 20A, 20B has a distal end 23 that forms a part in contact with the lens, And a method of checking the state of the contact portion 23, the checking method comprising: The profile 29 has a predetermined shape, the contour of which is brought in between the sensors 20A, 20B so that the sensor contacts each surface of the template 29 and is pre-mounted on the support 7. step, Controlling the displacement of the template 29 relative to the sensors 20A, 20B and measuring the corresponding displacement of the sensor, and And a step consisting of deriving information about the shape of the contact portion (23) therefrom. A spectacle lens processing tool suitable for carrying out the adjustment method according to any one of claims 1 to 4.

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