JP2601593B2 - Lens shape measurement mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is based on lens frame shape data.
Contact the lens surface of the lens to be processed
The present invention relates to a lens shape measuring mechanism for measuring the thickness of a lens .

[0002]

2. Description of the Related Art Conventionally, in a lens grinding apparatus, a rotating grindstone is used to grind a peripheral portion of a circular lens in accordance with a lens frame of an eyeglass frame. In addition, a beveling process is performed on a peripheral portion of the lens that is ground according to the shape of the lens frame so that the lens fitted to the lens frame does not easily come off the eyeglass frame. This beveling is also executed by the lens grinding device continuously with the grinding. Therefore, in order to increase the accuracy of the lens grinding process and accurately set the bevel position, the shape data is accurately measured from the lens frame of the spectacle frame, and the workpiece is processed according to the lens thickness designed for each wearer. It is necessary to measure the three-dimensional shape of the lens.

[0003] The three-dimensional shape of a processed lens is generally based on polar coordinate data (r, θ) obtained by a lens frame shape measuring device, and is coincident with or parallel to the lens rotation axis (hereinafter simply referred to as “Z axis”). The thickness of the lens is measured above, and is obtained as shape data using the measured value as the Z value. As a lens shape measuring mechanism for measuring the Z value, for example, there is a device of a lens grinding device disclosed in Japanese Utility Model Application Laid-Open No. 61-195960.

The present invention is a lens grinding apparatus having a carriage having a lens rotation axis for holding a lens to be processed and rotating the lens around a lens axis, and a grindstone for grinding the lens to be processed. In this lens grinding apparatus, a lens shape measuring means including at least one feeler (measurement element) capable of contacting a lens to be processed and a detecting means for detecting a moving amount of the feeler is housed in the casing of the carriage. It is configured. According to the configuration of such a conventional lens grinding device, not only is the carriage and the grindstone formed as one unit, but also it can be installed in a narrow place without changing the size of the device, and the lens shape can be easily adjusted. And has the advantage of being easy to use in lens grinding.

When the shape of a plastic lens is measured by a so-called lens shape measuring mechanism for measuring a Z value, it is necessary to take care that the feeler does not damage the lens surface because the feeler comes into contact with the lens surface. is there. Therefore, it is conceivable to provide a mechanism for controlling the moving speed in addition to the mechanism for bringing the feeler into contact with the lens surface or moving it away from the lens surface before and after the measurement of the Z value. In the lens shape measuring mechanism described in the above-mentioned publication, the feed screw is rotationally controlled by a pulse motor, two moving stages screwed to the feed screw are moved, and the feelers are respectively brought into contact with both surfaces of the lens. Let me.

[0006]

However, if an attempt is made to control the speed at which the feeler moves by the pulse motor,
Speed data must be stored in a motor control unit that outputs a command pulse to the pulse motor, and speed data corresponding to the position of the moving stage must be commanded to the pulse motor. For this reason, the control is performed by the CPU, which causes a problem in cost and also complicates the mechanism.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a lens shape measuring mechanism which controls the moving means of the feeler by a simple mechanism to reduce the impact when the feeler comes into contact with the lens surface. To provide.

[0008]

According to the present invention, there is provided a lens shape measuring mechanism for measuring the thickness of a lens to be framed based on lens frame shape data prior to lens grinding. A lens holding unit for rotatably holding the lens to be processed in a plane orthogonal to the lens axis thereof, and a first and a first unit which is urged in a front surface direction and a rear surface direction of the lens to be brought into contact with the lens surface. A second tracing stylus; a moving amount measuring means for measuring a moving amount of the first and second tracing stylus in the lens axis direction by rotating the lens to be processed around a lens axis; Before and after measuring the thickness of the processed lens, the distance between the first and second tracing stylus at least exceeds the thickness of the processed lens held by the lens holding unit. A feeler moving means for moving the child,
By controlling an exciting current flowing through an exciting coil of an electromagnetic actuator that operates the tracing stylus moving means, the first and second
And a shock reducing means for reducing a shock when the tracing stylus contacts each lens surface.

[0009]

In the lens shape measuring mechanism, an electromagnetic actuator for operating the tracing stylus moving means is used, and the shock reducing means controls the exciting current flowing through the exciting coil of the electromagnetic actuator, so that the first and second tracing styluses are moved. Shock when contacting each lens surface is reduced. The first and second tracing styluses are respectively urged in the front surface direction and the back surface direction of the lens to be processed and come into contact with the lens surface, and the lens shape is measured by the movement amount measuring means. Therefore, before and after measuring the thickness of the processed lens, the tracing stylus moving means moves the first and second tracing styluses until the distance between the first and second tracing stylus exceeds at least the thickness of the processed lens held by the lens holding unit. The second tracing stylus is moved in the direction of the front surface and the back surface of the lens to be processed.

If such an electromagnetic actuator is used as an impact reducing means, the configuration of a lens shape measuring mechanism for contacting the lens surface of the lens to be machined to be framed based on the lens frame shape data and measuring the thickness thereof is provided. Can be simplified.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a perspective view showing a schematic configuration of a lens grinding device provided with the lens shape measuring mechanism of the present invention. In the lens grinding apparatus 1, a grinding wheel for grinding a peripheral edge and a beveling wheel for beveling are provided side by side as a grinding wheel 11 for processing a lens to be processed in a substantially central portion of a base 10. The lens holding unit 12 includes a slide bearing 1 mounted on a slide shaft 14 between two bearings 13 fixed on the base 10.
5 is fixed. The slide shaft 14 is held by a moving unit (not shown) (a Z-axis motor in FIG. 1 described later) so as to be movable in the Z-axis direction in the figure and rotatable between the bearings 13, 13. Numeral 12 can move vertically and horizontally on the grindstone 11 of the base 10. The lens holding unit 12 has a U-shape in plan view that forms a recess at a substantially central portion on the near side. A lens to be processed (not shown) is provided in a concave portion of the lens holding unit 12 by lens support shafts 16 and 16 whose rotation is controlled.
Are rotatably held in a plane perpendicular to the lens axis.

The Y-axis moving mechanism 17 rotates the lens holding unit 12 around the slide shaft 14 and positions the front side thereof in accordance with the rotation of the lens support shaft 16. It comprises a rotating disk 18, an abutment member 19 that moves up and down on the base 10, and a moving means (a Y-axis motor in FIG. 1 described later). On the base 10 and on the front side of the grindstone 11, a measuring instrument storage chamber 20 for storing a later-described measuring element and a movement amount detecting means is arranged. Further, inside the lens holding unit 12, a chucking motor that slides one of the lens support shafts 16 to hold the lens to be processed, the lens support shaft 1 and the like.
A drive means (a lens axis motor of FIG. 1 described later) for rotating and driving the motor 6 is built in.

At the time of grinding, the main lens incorporated in the base 10 rotates the grindstone 11 at a high speed so that the lens support shafts 16, 16 and the lens shaft are held in alignment with each other. Is ground by a grinding wheel. At this time, the processing amount to be ground is instructed as a predetermined amount set for each rotation angle of the lens axis by controlling the Y-axis moving mechanism 17 and the lens axis motor based on the frame shape data. In the beveling, the lens holding unit 12 is moved in the Z-axis direction, and the peripheral edge of the lens to be processed is positioned at the position of the beveling grindstone. Thereafter, while pressing the periphery of the lens to be processed against the beveling grindstone, the lens holding unit 12 is further moved in the left-right direction along the Z axis, so that the bevel corresponding to the lens frame of the spectacle frame is formed on the periphery of the lens to be processed. It is formed.

FIG. 2 is a perspective view showing a state where the opening / closing door 30 of the measuring instrument storage chamber 20 is opened. The surface of the lens to be processed,
First and second tracing styluses 21 and 22 respectively contacting the back surface
Is an upper end surface of a shaft 23 that moves up and down in the storage chamber 30 and is supported by a rotatable arm. In the drawing, each arm is in the retracted position, and the state in which the tracing styluses 21 and 22 are stored in the measuring device storage chamber 20 is shown. In this lens grinding apparatus, since the measuring device is arranged outside the lens holding unit 12, the lens shape measuring mechanism can avoid the influence of vibration during lens grinding.

FIG. 3 is a perspective view showing an internal mechanism of the measuring instrument storage chamber 20. The base 10 is supported by the side walls 31 and 32 from the left and right below the base. These side walls 31,
An interlocking shaft 33 is rotatably hung between 32,
The interlocking shaft 33 is connected to a pulse motor 34 by a belt 35. Further, belts 38 and 39 are hung on two pulleys 36 and 37 on the left and right sides of the interlocking shaft 33. Also, two guide shafts 40 and 41 are vertically arranged parallel to each other on the left and right sides of the lower surface of the base 10, and are suspended by two constant load springs 42 and 43 on the front surface of the base 10. The vertical movement box 44 is configured to move up and down along the guide shafts 37 and 38.

The shaft 23 supporting the tracing styluses 21 and 22 at the upper end surface is fixed to the upper plate of the vertically moving box 44. Here, the left and right arms 24 and 25 of the tracing styluses 21 and 22
The rotational position of each of the shafts is controlled by a center shaft that rotates independently in the shaft 23. A step motor 45 for rotating the arms 24 and 25 between the measurement position and the retracted position, and an encoder 46a for detecting the amount of movement of the arms 24 and 25 in the lens axis direction are provided inside the vertical movement box 44.
(Encoder A in FIG. 1 described later), arm 2 at the measurement position
A solenoid (a so-called electromagnetic actuator) provided with an operating piece (amateur) for opening 4, 25 to a predetermined angle.
7 and the like are arranged. The solenoid 47 controls the excitation current flowing through the excitation coil while controlling the arms 24 and 25.
And an impact reducing unit for controlling the operation of (1) to reduce the impact when the tracing styluses 21 and 22 come into contact with the respective lens surfaces.

Further, the arms 24 of the tracing styluses 21 and 22,
Rotatable feelers 26 and 27 are provided at the distal end of the lens 25, and come into contact with the lens 28 to be processed. Prior to the measurement, an origin sensor 48 for measuring the amount of vertical movement of the arms 24 and 25 and a limit sensor 49 for setting an upper limit thereof are provided along the left guide shaft 40 of the vertical movement box 44. Have been. Also,
The retracted positions of the arms 24 and 25 are detected by a sensor 52 based on the rotational position of a pulley 51 connected via a step motor 45 and a belt 50. The arm 24 of the left tracing stylus rotates integrally with the arm pulley 53, and the arm 25 of the right tracing stylus rotates integrally with the arm pulley 54, so that the rotational position of the former arm pulley 53 is detected by the encoder 46a. The rotation position of the latter arm pulley 54 is detected by another encoder (not shown) (an encoder B in FIG. 1 described later).

FIG. 4 is an explanatory view showing an opening / closing mechanism of an opening / closing door 30 provided in the measuring instrument storage chamber 20. On the base 10 adjacent to the measuring instrument storage chamber 20, a motor 60 and a reduction gear 61 are arranged. An arm 63 for pushing up the door 30 is connected to the rotating shaft 62, and the arm 63 is driven to rotate by a motor 60 via a gear 61. The opening / closing door 30 of the measuring instrument storage chamber 20 is normally kept closed by a spring 64, and the arm 63 rotates from a horizontal position to a vertical position during measurement, so that the opening / closing door 30 is opposed to the spring 64. Pushing up.

FIG. 1 is a block diagram showing a measurement control mechanism using a tracing stylus in a lens shape measurement mechanism of the present invention. The encoders 46a and 46b are respectively composed of first and second encoders.
Of the lens 28 to be processed in the Z-axis direction from the tracing styluses 21 and 22 are measured. The measured Z value is
The data is input to the control circuit 70 of the lens grinding device connected via the input interface 77. The control circuit 70 includes a central processing unit (CPU) 71, a ROM 72 for fixedly storing a control program, and a RAM 73 for storing input data and intermediate results of processing.

The pulse motor 34 has an output interface 7
The vertical movement box 44 is driven up and down in the measuring instrument storage room 20 in accordance with a command from the control circuit 70 via the control circuit 70 to determine the lens measurement position by the feelers 26 and 27. The stepping motor 45 is also connected to the control circuit 70, and rotates the arm 24, 25 of the tracing stylus to the retracted position when measurement is not performed in accordance with a command from the control circuit 70. The arms 24 and 25 are turned to the measurement positions. In addition, solenoid 4
7 is connected to the output interface 78 via the voltage adjustment circuit 47a. The amount of movement of the vertical movement box 44 by the pulse motor 34 is determined by the vertical movement origin sensor 4.
8 and the signal from the vertical movement limit sensor 49
Received and controlled by. Also, the step motor 45
The amount of movement between the evacuation position and the measurement position is controlled by the control circuit 70 receiving a signal from the evacuation position sensor 52. The voltage adjustment circuit 47a adjusts a voltage signal output based on an excitation command to the excitation coil in accordance with a moving distance of a lever (operating piece) 47b of the solenoid 47. The voltage adjustment circuit 47a will be described later in detail with reference to FIG. The control circuit 70 controls the Y-axis motor 74 and the Z-axis motor 7 in addition to the door opening / closing motor 60.
5 and the lens axis motor 76 are controlled.

If the shape data of the spectacle frame measured before the lens grinding is stored in the RAM 73 of the control circuit 70, the pulse motor 34 is controlled based on the frame shape data before grinding the unprocessed lens. Control
The three-dimensional shape data (r, θ, Z) can be measured on the front and back surfaces of the lens. Where r is the distance from the lens axis,
θ is the rotation angle from the reference position, Z is Z from the lens center
Axial distance.

Next, the procedure for measuring the lens shape in the lens shape measuring mechanism of the present invention will be described. An eyeglass frame is set in a frame shape measuring unit provided in the apparatus, the frame shape is measured, and stored in the RAM 73 of the control circuit 70.
Next, the lens to be processed is moved to the lens support shaft 1 shown in FIG.
6 and 16 and the lens support shaft 1 on the base 10.
6 is set at a predetermined position. Next, the door opening / closing motor 60
, The opening / closing door 30 of the measuring instrument storage chamber 20 is opened, and the pulse motor 34 is driven to move the vertical movement box 44 upward to a predetermined Y-axis position based on the frame shape data. When the door 30 is opened, the tracing stylus arm 24,
25 are both rotated by about 90 ° and moved to the measurement position. Thereafter, the CPU 71 outputs the arms 24 and 2 of the tracing stylus.
When a command to expand the number 5 is output, the two arms 24 and 25
The solenoid 47 is driven until the distance between the two becomes sufficiently larger than the lens thickness. After that, while controlling the Y-axis moving mechanism 17 to adjust the angle of the lens holding unit 12,
By controlling the lens axis motor 76, the lens is rotated to the reference position.

After the lenses 24 and 25 are closed and the feelers 26 and 27 are brought into contact with the front and back surfaces of the lenses, the lens shaft motor 76 and the pulse motor 34 are converted into frame shape data. And the encoders 46a and 46b measure the Z-axis data of the front and back surfaces of the lens, respectively.

Here, an example of a power transmission mechanism for moving the arms 24 and 25 to the measurement position and a control procedure thereof will be described with reference to FIG. FIG. 6 shows a vertical movement box 44.
FIG. 3A schematically illustrates a power transmission mechanism for rotating the arms 24 and 25 in FIG.
FIG. 6B is a top view of an arm pulley 53, and FIG. 7C is a top view of a rotary pulley 51.

An arm opening / closing pin 55 that contacts the lever 47b of the solenoid 47 is fixed to the upper surface of the arm pulley 54 that rotates integrally with the arm 25. Pins A and B are provided on the lower surface of the arm pulley 54 and the upper surface of the arm pulley 53, respectively, and each end of a helical spring 56 wound around an axis is fixed to these pins A and B. Arm pulleys 53 and 54 are wound by a coil spring 56.
Are biased in a rotational direction approaching each other. Pins C and D are provided on the lower surface of the arm pulley 53 and the upper surface of the rotary pulley 51, respectively.
Accordingly, the arm pulley 53 and the rotary pulley 51 are urged in a rotating direction approaching each other. The rotary pulley 51 is connected to the step motor 45 by the belt 50 and is rotated.

When the arms 24 and 25 are rotated to the measurement position, the lever 47b of the solenoid 47 is at the release position where it does not abut the arm opening / closing pin 55. For this reason, when the step motor 45 is rotated in the direction of the arrow in the figure, the pins A and B and the pins C and D come into contact with each other by the winding springs 56 and 57 as shown in FIGS. While maintaining this state, the rotation of the rotary pulley 51 is transmitted to the arm pulleys 53 and 54, respectively, and the arms 24 and 25 rotate integrally to the measurement position.

Next, the arm 24 reaching the measurement position,
When the 25 is opened by a predetermined angle, the lever 47b of the solenoid 47 is operated as shown in FIG. Then, the rotation of the arm pulley 54 is regulated by the lever 47b,
The right arm 25 stops. On the other hand, when the step motor 45 is continuously rotated in the same direction, only the left arm 24 is further rotated. As a result, as shown in FIG. 6C, the pins C and D maintain a state in which they are in contact with each other by the helical spring 57. However, as shown in FIG.
The rotation pulley 51 stops at a distance from each other until the rotation force of the rotation pulley 51 and the force of the winding spring 56 are balanced.

In this state, the pulse motor 34 is driven,
The vertical movement box 44 is moved upward to a predetermined Y-axis position based on the frame shape data, and after the lens to be processed 28 is positioned between the arms 24 and 25, as shown in FIG. The arm opening / closing pin 55
To the release position where it does not come into contact with. At this time, the voltage adjusting circuit 47a adjusts the moving speed of the lever 47b so that the feelers 26 and 27 do not damage the lens surface. That is, the left arm 24 slowly approaches the left surface of the lens 28 to be processed, and the right arm 25 is urged by the helical spring 56 to slowly approach the right surface of the lens 28 similarly. Therefore, when the rotary pulley 51 is further rotated by several degrees and then stopped, the lens
The arms 24 and 25 enter the measurement state.

That is, as shown in FIGS. 8B and 8C, the pins A and B and the pins C and D are kept apart from each other to some extent against the force of the helical springs 56 and 57, respectively. Therefore, the ends of the arm pulleys 53 and 54 are in contact with the front and back surfaces of the lens 28 to be processed at a predetermined pressure. As a result, by controlling the height of the vertical movement box 44 in accordance with the lens rotation position, the movement of the feelers 26 and 27 at the tips of the arms 24 and 25 is controlled by the arm pulleys 53 and
The data is reliably transmitted to the encoders 46a and 46b via the, and the Z-axis data of the front and back surfaces of the lens can be measured.

When the measurement is completed, the reverse procedure of the above operation procedure is executed. That is, the right arm 25 is opened by operating the solenoid 47. After the lens holding unit 12 is moved upward by the Y-axis moving mechanism 17 to retract the lens, the solenoid 47 is released, and then the step motor 45 is rotated in the opposite direction to move the arms 24 and 25 to the retracted position. Let it return. After that, the vertical movement box 44 is processed, and then the door 30 is closed.

As described above, in the measurement of the lens shape in the lens shape measuring mechanism of the present invention, the pins A and B and the pins C and
D is integrally formed by the winding springs 56 and 57 and the arm pulley 5
3, 54 and the rotating pulley 51 rotate at the same time to move the two arms 24, 25 between the retracted position and the measurement position. At the measurement position, the arm 24 is opened by regulating the rotation of the arm pulley 54 on one side by the solenoid 47 and rotating only the other arm pulley 53. Thereafter, when the lever 47b is released by the solenoid 47, the pins A,
B and between the pins C and D are helical springs 56 and 57, respectively.
Therefore, the two arms 24 and 25 are closed, and the lens 28 to be processed can be sandwiched.

FIG. 9 is a diagram showing a state in which three-dimensional shape data (r, θ, Z) on the front and back surfaces of the lens are measured.
(A) is a lens front view, (B) is a side sectional view. 2
While the arms 24 and 25 are closed, the feelers 26 and 27 are brought into contact with the front and back surfaces of the circular lens 28 to be processed, and are moved up and down based on the frame shape data (r, θ) measured from the spectacle frame. The Z value is measured by moving the movement box 44 up and down with respect to the lens support shaft 16. The trajectory 28a is a trajectory where the feelers 26 and 27 come into contact with the lens surfaces. In this case, as shown in FIG. 9B, the feelers 26 and 27 are constituted by cylindrical rotating bodies having a rectangular cross section. Then, in order to match the positions where the feelers 26 and 27 abut on the front and back surfaces of the lens, the feeler 26 abutting on the back surface becomes higher by the thickness thereof.
The trajectories 28a on the front and back surfaces of the lens are made to match by making the heights of the arms 24 and 25 different. Thereby, even when the feelers 26 and 27 come into contact with the lens surfaces and are worn, the measurement error of the Z value can be easily adjusted as compared with the shape of the feeler having a sharp tip contact portion, and the feeler can be processed. It will be easier.

Although the above description is of a case where the lens shape is measured prior to the grinding, the lens shape measuring mechanism of the present invention can also measure the peripheral thickness of the ground lens.

FIG. 10 is a circuit diagram showing an example of the voltage adjusting circuit 47a. When the CPU 71 of the control circuit 70 instructs the solenoid to be excited, the command signal becomes L
The signal is input via the ED 80 as a signal for turning on the phototransistor 81. The phototransistor 81 has its emitter side grounded and its collector side connected to inverters 82 and 83, respectively. The output of the inverter 82 is connected to an inverter 84, which is connected to the base of the transistor 85 via the inverter 84.
The transistor 85 is turned on when a command signal is input. Further, a power supply voltage (24 volts) is connected to the emitter terminal of the transistor 85, and a capacitor 86 is connected to the collector terminal. Therefore, when the transistor 85 is turned on, the capacitor 8
6 is charged quickly. The connection point between the transistor 85 and the capacitor 86 is connected to the output side of the inverter 83, and is also connected to the base of the transistor 87 for current amplification. Also, the transistor 87
A current amplification circuit is formed together with the transistor 88, and is connected to an excitation coil of the solenoid 47 via a connector 89. Therefore, when the command signal disappears after the capacitor 86 is charged, the transistor 85 is turned off,
The charge of the capacitor 86 is gradually discharged, and the exciting current gradually decreases.

FIG. 11 is a plan view showing the solenoid 47 of the lens shape measuring mechanism. The solenoid 47 is fixed to a side wall 44a of the vertical movement box 44, and has an exciting coil (not shown) and an operation piece 47c that moves straight by the excitation coil in a pull-type solenoid body. A lever 47 is provided on the side wall surface 44a on the side where the operating piece 47c of the solenoid 47 projects.
The support piece 44b that rotatably supports b is fixed. The lever 47b and the operating piece 47c of the solenoid 47
Are connected by a connecting member 47d, and the operating piece 47c
Of the lever 47b via the connecting member 47d.
Has been converted to a rotational motion. This solenoid 47 is
The distal end portion of the lever 47b is arranged at a position where it can contact the arm opening / closing pin 55 of the arm pulley 54. When the exciting current flows through the exciting coil, the operating piece 47c
Moves to the left in the drawing, the tip end of the lever 47b and the arm opening / closing pin 55 of the arm pulley 54 come into contact, and the arm 25 of the tracing stylus is opened (see FIG. 7). The exciting coil of the solenoid 47 is connected to the connector 89.
Is connected to the voltage adjustment circuit 47b via the.

Next, the operation of the solenoid 47 connected to the connector 89 of the voltage adjusting circuit 47a in FIG. 10 will be described. When the CPU 71 instructs the solenoid 47 to be excited to open the arm of the tracing stylus, electric charge starts to be accumulated in the capacitor 86. Then, a large amount of current rapidly flows through the exciting coil of the solenoid 47 at the beginning,
When the charge of the capacitor 86 approaches saturation, the change in the exciting current becomes small, and the operating speed of the operating piece 47c also becomes slow.
For this reason, the lever 47b rotates from the position of 47e shown in FIG. 11, and its tip portion slowly contacts the arm opening / closing pin 55 of the arm pulley 54. Therefore, when the feeler is separated from the lens at the end of the measurement, there is no risk of damaging the lens surface.

Conversely, even when the measurement arm is closed and the measurement is to be started, the charge accumulated in the capacitor 86 is initially discharged little by little, so that the exciting current does not decrease rapidly. Therefore, the operation piece 47c of the solenoid 47 moves to the left in FIG. 11, but its operation is gentle, and the arm pulley 54 rotates slowly. As a result, the feeler comes into contact with the lens surface gradually approaching, so that the impact can be reduced.

In the above description, the case where the electromagnetic actuator of the present invention is applied to the lens shape measuring mechanism of the lens grinding device has been described. However, the characteristic of the present invention resides in that the exciting current of the electromagnetic actuator used in the lens shape measuring mechanism is adjusted by the voltage adjusting circuit to control the operating speed of the operating piece. It is not limited to such an embodiment. That is,
When controlling the contacted object indirectly according to the movement of the operating piece, it is placed on various devices that are required to reduce the impact on the contacted object, for example, on a conveyor belt carrying a delicate conveyed object The same effect can be achieved by applying the present invention to an interlock device, a gate opening / closing device, a shutter opening / closing device, or the like.

As the electromagnetic actuator, besides a direct acting solenoid for linearly moving an operating piece (an armature) of a permanent magnet based on an exciting current of a solenoid coil, a rotary solenoid for rotating the operating piece can also be used.

[0040]

As described above, according to the present invention, the measuring element
Use an electromagnetic actuator to actuate
To the excitation coil of the electromagnetic actuator
The first and second tracing styluses control each excitation current by controlling the excitation current.
Impact on the contact surface is reduced.
With a simple mechanism, when the feeler touches the lens surface
Shock can be reduced and the front and back of the lens can be measured simultaneously.
To improve the measurement accuracy of the three-dimensional shape.
it can.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a measurement control mechanism using a tracing stylus in a lens shape measurement mechanism of the present invention.

FIG. 2 is a perspective view showing a state where an opening / closing door of a measuring instrument storage chamber is opened.

FIG. 3 is a perspective view showing an internal mechanism of a measuring instrument storage chamber.

FIG. 4 is a perspective view showing an opening / closing mechanism of an opening / closing door.

FIG. 5 is a perspective view showing a schematic configuration of a lens grinding apparatus including a lens shape measuring mechanism of the present invention.

FIG. 6 is a diagram schematically showing a power transmission mechanism for rotating a tracing stylus.

FIG. 7 is a diagram schematically showing a power transmission mechanism that rotates a tracing stylus.

FIG. 8 is a diagram schematically showing a power transmission mechanism for rotating a tracing stylus.

FIG. 9 shows three-dimensional shape data (r, θ,
FIGS. 3A and 3B are diagrams illustrating a state of measuring Z), wherein FIG. 3A is a front view of a lens, and FIG.

FIG. 10 is a circuit configuration diagram illustrating an example of a voltage adjustment circuit.

FIG. 11 is a plan view showing a solenoid of the lens shape measuring mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lens grinding apparatus 10 Base 11 Grinding stone 12 Lens holding unit 16 Lens support shaft 17 Y-axis moving mechanism 20 Measuring instrument storage room 47 Solenoid 47a Voltage adjustment circuit

Claims (2)

(57) [Claims] 1. A lens shape measuring mechanism for measuring a thickness of a lens to be processed to be framed based on lens frame shape data prior to lens grinding, wherein the lens to be processed is positioned within a plane perpendicular to the lens axis. A lens holding unit that rotatably holds the lens, first and second tracing styluses that are urged in a front surface direction and a rear surface direction of the lens to be processed and come into contact with a lens surface; Moving amount measuring means for measuring the moving amount of the first and second tracing styluses in the lens axis direction by rotating the first and second tracing styluses; and the first and second before and after measuring the thickness of the lens to be processed. Measuring element moving means for moving the first and second measuring elements to a position where the distance between the measuring elements exceeds at least the thickness of the lens to be processed held by the lens holding unit; The first by controlling the exciting current flowing through the exciting coil of the electromagnetic actuator for actuating the stage, the second
And a shock reducing means for reducing a shock when the probe comes into contact with each lens surface. 2. The method according to claim 1, wherein the impact reducing unit sucks the operating piece,
Alternatively, the electromagnetic actuator includes an excitation coil that is excited to extrude, and a voltage adjustment circuit that adjusts a voltage signal output based on an excitation command to the excitation coil in accordance with a moving distance of the operating piece, 2. The lens shape measuring mechanism according to claim 1, wherein the movement of each of said measuring elements is controlled by an operating piece.