JPH06297309A - Automatic lens edger - Google Patents

Abstract

PURPOSE:To enable accurate measurement even in a soft and thin plastic lens by rotating the lens in such a state that the end surface of a spectacle lens has been received by a V-groove, and by detecting the displacement in the perpendicular direction to the V-groove for obtaining the width-directional center of the end surface of the lens. CONSTITUTION:In an automatic lens edger by which a lens is successively ground by a rough grindstone 24, intermediate grindstones 25, 26, and a finishing grindstone 27 so that the outline of a spectacle lens 6 fixedly held between chucking shafts can be conformed with the shape of a spectacle frame; when the orbit of the width- directional center of the end surface of the lens 6 is to be obtained, the end surface of the lens 6 is fitted in the V-groove provided to the outer circumference of the intermediate grindstone 25, and only the lens 6 is turned by a motor. By turning the lens 6 while sliding along the sloped surface of the V-groove, the aligning of the thickness center of the lens end surface with the width center of the intermediate grindstone 25 can be carried out. The movement of a head frame 5 at that time is detected by an encoder through a level arm 4 and a belt 23, and on the basis of this movement and the change in the turning angle of the lens, the width center of the end surface of the lens 6 is calculated by a control unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic ball slicing machine, which grinds a spectacle lens so that the plane shape of the spectacle lens exactly matches the shape of a spectacle frame.

[0002]

2. Description of the Related Art In order to properly fit a spectacle lens into a spectacle frame, grinding is performed so that the peripheral end surface of the spectacle lens matches the groove of the spectacle frame and the plane shape of the spectacle lens matches the plane shape of the spectacle frame. There must be.

The applicant proposes, in Japanese Patent Publication No. 58-43227, an automatic ball slicing machine that grinds the peripheral edge surface of the spectacle lens into a bevel (convex shape of the rim of the spectacle lens) that exactly matches the groove of the spectacle frame. And made it concrete.

These automatic ball mills will be described with reference to FIGS.

A shaft 3 is supported by a bearing 2 fixed to a base 1 so as to be slidable in the axial direction (horizontal direction), a level arm 4 is fixed to the shaft 3, and a head frame 5 is rotatably attached. A recess 7 for chucking the lens 6 is formed in the head frame 5, and a pair of chucking shafts 8 and 9 penetrating the recess 7 are provided. The chucking shaft 8 on the level arm 4 side is rotatable. The level arm side end is configured so that the copying die 10 relating to the outer shape (shape in the radial direction of the lens) can be detachably attached, and the chucking head 11 is provided at the other end of the chucking shaft 8.

Further, a guide plate 18 having a guide surface having the same level and the same radius as the grinding surface of a grindstone, which is positioned below the copying die 10, is provided on the level arm 4, and the copying die 10 is mounted on the guiding plate 18. When the chucking shafts 8 and 9 rotate while making contact with each other, the head frame 5 moves up and down according to the shape of the copying die 10. The other chucking shaft 9 is provided rotatably and slidably in the axial direction, the chucking head 12 paired with the chucking head 11 is attached to one end, and the chucking shaft 9 is attached to the other end in the axial direction. It is connected to an actuator 13 such as an air cylinder that is driven by the.

A lens rotation motor 16 and a lens rotation angle detection pulse encoder 17 are connected to the chucking shafts 8 and 9 via gear trains 14 and 15, respectively. The rotation motor 16 and the rotation angle detection pulse encoder 17 are both provided on the head frame 5 so as to rotate integrally with the head frame 5. Horizontal drive pulse motor 19 to be parallel to the shaft 3
And the horizontal position detection pulse encoder 20 are arranged on the base 1, and the belt 2 is attached to the pulley 21 of the horizontal drive pulse motor 19 and the pulley 22 of the horizontal position detection pulse encoder 20.
3 is suspended to connect the belt 23 and the level arm 4.

The above-mentioned horizontal drive pulse motor 19 causes the pulley 21 to move accurately when energized, but the pulley 21 can freely rotate without resistance when not energized. Further, below the chucking heads 11 and 12, a required number of grindstones 2 are provided.
4, 25, 26, 27 are provided, and the grindstones 24, 25, 2
The support shafts 6, 27 are connected to a rotating device (not shown). The shape of the grinding surface of the grindstone is different depending on the application, the rough grinding wheel 24 is a flat surface, and the intermediate grindstones 25 and 26 have inclined surfaces 28 and 29 that are wider than the lens thickness.
Reference numeral 7 has the same shape as the groove of the spectacle frame.

The lens rotation angle detecting pulse encoder 17, the horizontal position detecting pulse encoder 20, and the horizontal drive pulse motor 19 are respectively connected to a control device 30, and the control device 30 is a storage device (microcomputer).
And a drive circuit, and the both pulse encoders 17, 20
The detection result is stored and the horizontal drive pulse motor 19 is driven based on the detection result. In addition, 3 in the figure
Reference numeral 1 is a roller, and 32 is a guide rail.

First, a copying die 10 conforming to the shape of the lens 6 to be ground is attached to the chucking shaft 8, and then the chucking heads 11 and 12 are aligned while aligning the lens 6 with the copying die 10 in the same posture. Hold at. In the lens thickness direction (horizontal direction), the center of the lens 6 and the center of the rough grinding stone 24 are substantially aligned. The rough grinding wheel 24 and the lens 6 are rotated to bring the lens 6 into contact with the rough grinding wheel 24 (in this state, the copying die 10 and the guide plate 18 are also in contact) and grinding is started. The lens 6 moves up and down according to the shape of the lens by the copying die 10, and the end face is ground flat. At this time, the lens end surface position fluctuates in the horizontal direction depending on the shape of the lens and the mounting posture.
It is enough to make the ground surface of the wide.

When the rough grinding is completed, the grindstone 24 for roughing and the lens 6 are separated from each other by a device (not shown), and the horizontal drive pulse motor 19 moves the head frame 5 through the belt 23, the level arm 4, and the shaft 3 to the grindstone for roughing 24. And the intermediate grindstone to be used for grinding are moved (this movement may be done manually).

When the lens 6 is positioned, the control device 30 is reset, and this position is set as a reference position. In this state, the horizontal pulse motor 19 is de-energized so that the head frame 5 can move in the horizontal direction without resistance. 6 is brought into contact with the intermediate grindstone 25 by gravity of the head frame 5 or the like to start grinding.

When the center of the lens in the horizontal direction and the center of the intermediate grindstone 25 do not coincide with each other, one corner of the lens 6 hits the inclined surface 28 of the intermediate grindstone 25 as shown in FIG. Due to the head frame 5 and the like, the own gravity W always acts downward on the lens 6,
Further, since the head frame 5 can freely move in the horizontal direction without resistance, the lens 6 eventually moves in the direction of arrow A along the inclined surface, and the centers of the lens 6 and the intermediate grindstone 25 coincide with each other. That is, the lens 6 follows the horizontal position change of the lens end face,
It always moves horizontally so that the center of the lens and the center of the intermediate grindstone 25 coincide with each other. The movement of the head frame 5 at this time is detected by the horizontal position detection pulse encoder 20 via the level arm 4 and the belt 23 and input to the control device 30, and the rotation angle change of the lens 6 is detected by the lens rotation angle detection pulse encoder 17. Input to the control device 30. The control device 30 stores the error between the center of the lens and the center of the grindstone at the time of positioning, and the position change of the end face caused by rotating the lens 6 based on the previous two inputs, using the rotation angle as a parameter.

When the intermediate grinding is completed, the lens 6 is separated from the intermediate grindstone 25, and the horizontal drive pulse motor 19 moves the lens 6 by the separated distance between the intermediate grindstone 25 and the finishing grindstone 27.
This movement is achieved by the control device 30 driving the horizontal drive pulse motor 19 by a signal input to the control device 30 in advance.

Next, the finish grinding is synchronized with the rotation of the lens so that the position change of the end face stored by the control device 30 matches, and the head frame 5 is driven by the horizontal drive pulse motor 19.
Is forcibly moved horizontally to form a circumferential projection that fits in the groove of the spectacle frame at the center position in the lens thickness direction.

When the curve of the groove of the spectacle frame does not match the center curve in the lens thickness direction, the curve of the groove of the spectacle frame is set and input to the control device 30, and signals from both encoders 17 and 20 are input. Even if the center curve of the lens and the groove curve of the spectacle frame are different, if the horizontal movement pulse motor 19 is driven by the correction program by correcting the horizontal movement program of the head frame 5 synthesized by the above so as to match the groove curve. It is possible to form a circumferential projection that matches the groove of the spectacle frame.

[0017]

As described above, the center of thickness of the end face of the lens 6 and the width center of the grindstone are aligned with each other by the intermediate grindstone 2.
When the lens 6 is one-sided against the slope 28 of the V groove of 5,
The lens 6 slides down along the slope 28 in the valley direction (the direction of arrow A in FIG. 8), and the lens 6 moves in the horizontal direction to align the thickness center of the end face of the lens 6 with the width center of the intermediate grindstone 25. However, in recent years, thin plastic lenses have become widespread, and there are many soft lens materials with a small cutting allowance. Therefore, the cutting allowance may be cut before the center of the thickness of the lens end face and the width center of the grindstone are completed, and the lens 6 cannot follow the center of the V groove, and the thickness center of the end face of the lens 6 is measured. There are things you can't do.

In view of the above situation, the present invention aims to provide an automatic ball slicing machine capable of accurately and reliably measuring the thickness center of the end face of a lens such as a plastic lens having a small thickness and a soft material. Is.

[0019]

According to the present invention, a lens is rotatably supported by a tiltable head frame, the lens is brought into contact with a grindstone while being rotated, and the lens outer shape is ground into a predetermined shape. In an automatic ball slicing machine, a V groove having an inclined surface that further expands the plate thickness of the spectacle lens and the end surface of the spectacle lens are brought into contact with the V groove, and the end surface of the spectacle lens is made to face the V groove. A displacement detector that is rotatable and detects a displacement in a direction perpendicular to the V groove generated by this relative rotation, a rotation detector that detects rotation of the lens, and a detection result of the displacement detector and the rotation detector. And a control device for obtaining the center of the end face width of the spectacle lens.

[0020]

The spectacle lens is brought into contact with the V-shaped groove, and the spectacle lens and the V-shaped groove are relatively rotated, so that a centering action is generated between the V-shaped groove and the spectacle lens, which is obtained between the V-shaped groove and the spectacle lens. By detecting the centering information with the displacement detector and detecting the rotational position with the rotation detector, the locus of the width center of the spectacle end face is obtained, and grinding is performed based on the obtained locus.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the same parts as those shown in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted.

Support shaft 35 for the grindstones 24, 25, 26, 27
Is rotatably supported via a bearing 36, and the support shaft 35
A motor 38 is coupled to this via a one-way clutch 37. The allowable rotation direction of the one-way clutch 37 is designed to rotate only in the same direction as the rotation direction of the chucking shafts 8 and 9 rotated by the lens rotation motor 16. The support shaft 35 is constrained in the opposite direction.

As described above, when the lens 6 is ground, the support shaft 35 and the grindstones 24, 25, 26, 27 by the motor 38 via the one-way clutch 37.
To rotate.

The operation of this embodiment will be described.

Grinding wheel 24 for chucking and roughing the lens 6
Since the step of grinding the end face of the lens 6 to be flat by the above is similar to that of the automatic ball shaving machine of Japanese Patent Publication No. 58-43227, the description thereof will be omitted, and the subsequent step of obtaining the locus of the width center of the end face of the lens 6 will be described. .

The end face of the lens 6 is fitted into the V groove of the intermediate grindstone 25, the driving of the motor 38 is stopped, and only the lens 6 is rotated by the lens rotating motor 16.

As described above, since the support shaft 35 rotates only in the same direction as the lens 6 by the action of the one-way clutch 37, the lens 6 is rotated while the lens 6 is in contact with the intermediate grindstone 25. Then, the intermediate grindstone 25 is restrained by the one-way clutch 37 and does not rotate, and the lens 6 rotates while sliding on the slope 28 of the intermediate grindstone 25.

Intermediate grindstone 25 accompanied by sliding of the lens 6
The rotation of the lens 6 is performed while the movement in the direction of the arrow A shown in FIG. 8 is reliably generated, and the center of the thickness of the end face of the lens 6 and the center of the width of the intermediate grindstone 25 are reliably performed.

Here, the reason why the intermediate grindstone 25 is completely stopped is that when the lens 6 is rotated, the intermediate grindstone 25 follows and rotates due to the frictional force between the lens and the grindstone. When the grindstone follows the lens and rotates, the phenomenon that the lens does not slide down the slope and climbs in the opposite direction occurs. Therefore, the lens 6 cannot follow the center of the V groove.

Thus, the lens 6 follows the position change of the lens end surface in the horizontal direction, and always moves in the horizontal direction so that the center of the lens and the center of the intermediate grindstone 25 coincide with each other. The movement of the head frame 5 at this time is detected by the horizontal position detection pulse encoder 20 via the level arm 4 and the belt 23 and input to the control device 30, and the rotation angle change of the lens 6 is detected by the lens rotation angle detection pulse encoder 17. Input to the control device 30. The control device 30 stores the error between the center of the lens and the center of the grindstone at the time of positioning, and the position change of the end face caused by rotating the lens 6 based on the previous two inputs, using the rotation angle as a parameter.

The control device 30 includes a horizontal position detection pulse encoder 20 and a lens rotation angle detection pulse encoder 17.
A locus of the thickness center of the end surface of the lens 6 can be calculated from the data such as the above, and is used for the grinding control in the subsequent steps.

The operation after obtaining the locus of the thickness center of the end face of the lens 6 is the same as that of the automatic ball slicing machine of Japanese Patent Publication No. 58-43227, and therefore its explanation is omitted.

In the process of obtaining the locus of the thickness center of the end face of the lens 6 in the above embodiment, there is sliding in the rotational direction between the intermediate grindstone 25 and the lens 6 and the lens is not damaged. It is preferable that the contact pressure between and the intermediate grindstone 25 is small. Since this step does not involve grinding operation, a V groove may be used instead of the intermediate grindstone 25, and a centering disc having a high hardness and a small slip resistance may be used, or the V groove may be formed on the base 1. May be provided, or the support shaft 35 may be restrained in the step of obtaining the trajectory of the thickness center of the end face of the lens 6, so that an electromagnetic clutch brake is used instead of the clutch 37, and the brake is used. Needless to say, various modifications can be made without departing from the gist of the present invention, such as by restraining the support shaft 35.

[0035]

As described above, according to the present invention, the center of thickness of the end face of a lens can be accurately and reliably measured even with a thin lens such as a plastic lens and a soft material, and a desired bevel is formed on the lens end face. Can be formed.

[Brief description of drawings]

FIG. 1 is a plan view of a main part showing an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of a conventional example.

FIG. 4 is a front view of the conventional example.

FIG. 5 is a side view of the conventional example.

FIG. 6 is a detailed view of a chucking head portion.

7 (a), (b), (c), and (d) are explanatory views showing a finished shape of a grindstone grinding surface and a lens end surface.

FIG. 8 is an explanatory diagram showing the principle of lens alignment using an intermediate grindstone.

[Explanation of symbols]

 5 Head Frame 6 Lens 10 Copy Type 17 Lens Rotation Angle Detection Pulse Encoder 20 Horizontal Position Detection Pulse Encoder 24 Roughing Grinding Stone 25 Intermediate Grinding Stone 26 Intermediate Grinding Stone 27 Finishing Grinding Stone 28 Sloping Surface 29 Sloping Surface 30 Control Device

Claims (4)

[Claims] 1. An automatic ball slicing machine in which a lens is rotatably supported by a tiltable head frame and is brought into contact with a grindstone while rotating the lens to grind the lens outer shape into a predetermined shape. A V groove having an inclined surface that further expands than the plate thickness of the spectacle lens, and an end surface of the spectacle lens are brought into contact with the V groove so that the end surface of the spectacle lens can be relatively rotated with respect to the V groove. A displacement detector that detects a displacement in a direction perpendicular to the generated V groove, a rotation detector that detects the rotation of the lens, and a center of the end face width of the spectacle lens based on the detection results of the displacement detector and the rotation detector. An automatic ball shaving machine, comprising: 2. The automatic scouring machine according to claim 1, wherein the spectacle lens is forcibly moved in the thickness direction when the spectacle lens is ground, based on the center of the end face width of the spectacle lens determined by the control device. 3. A V-groove is formed on the grinding surface of the grindstone, and the rotation axis of the grindstone is constrained in the step of determining at least the end face width center of the spectacle lens in a direction opposite to the rotation direction of the spectacle lens. The automatic ball shaving machine according to claim 1, further comprising: 4. The automatic ball shaving machine according to claim 3, wherein the restraint means is a one-way clutch.