Abrading – Precision device or process - or with condition responsive... – Computer controlled
Reexamination Certificate
1999-05-28
2001-04-24
Hail, III, Joseph J. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
Computer controlled
C451S010000, C451S011000, C451S043000, C451S256000, C451S240000
Reexamination Certificate
active
06220929
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an eyeglass lens grinding apparatus for grinding the periphery of an eyeglass lens.
As disclosed in U.S. Pat. No. 5,347,762, a typical eyeglass lens grinding apparatus for grinding the eyeglass lens periphery is designed such that a lens to be processed is clamped by lens rotating shafts, and a carriage holding the lens rotating shafts are pivotably moved using a pulse motor so as to control an axis-to-axis distance between the rotating lens and an rotating abrasive wheel, thereby processing the lens while depressing the lens onto the abrasive wheel.
To prevent breakage and axial offset of the lens during processing, it is necessary to set processing pressure to an appropriate level. For this reason, the apparatus employs such a mechanism that a carriage is pressed by a spring force in the direction toward an abrasive-wheel rotating shaft during processing of the lens, and the carriage is relieved in a direction away from the abrasive wheel if the force exceeding the processing pressure adjusted by the spring force is applied to the lens.
The apparatus is further provided with a processing completion sensor for detecting whether or not the lens has been processed to a predetermined size. The apparatus controls the processing while monitoring (detecting) whether or not the relief mechanism works using this sensor.
If the apparatus having the above-described arrangement is further provided with a motor for adjusting the spring force of the relief mechanism, then it may be possible to adjust the processing pressure depending on the difference in the lens material prior to processing. However, the processing pressure is generally constant during processing. For this reason, if the processing pressure is set to a high level, an excessively high torque is applied to the lens rotating shafts in an early stage of processing where the lens diameter is large, which may results in the axial offset. If the processing pressure is set to a low level to prevent such situation, the overall processing time is long.
In addition, with apparatus having the above-described arrangement, the range in which processing has not been completed can be known by the processing completion sensor, but it has been impossible to ascertain how much such a portion remains unprocessed (unprocessed amount). For this reason, it has been impossible to change the processing conditions in correspondence with the unprocessed amount.
Further, the relief mechanism as described above is complex in construction, and is disadvantageous in terms of cost.
SUMMARY OF THE INVENTION
In view of the above-described drawbacks, it is an object of the present invention to provide an eyeglass lens grinding apparatus which has a simple arrangement and makes it possible to effect processing under appropriate conditions in correspondence with the shape of the subject lens being processed.
The present invention provides the followings:
(1) An eyeglass lens grinding apparatus for grinding a periphery of a lens, the apparatus comprising:
lens rotating means having lens rotating shafts for holding and rotating the lens;
abrasive wheel rotating means having an abrasive wheel rotating shaft for rotating at least one lens grinding abrasive wheel;
moving means for relatively moving the lens rotating shafts with respect to the abrasive wheel rotating shaft to thereby vary an axis-to-axis distance between the each of the lens rotating shafts and the abrasive wheel rotating shaft;
axis-to-axis distance detecting means for detecting the axis-to-axis distance varied by the moving means; and
control means for controlling processing based on a result of detection by the axis-to-axis distance detecting means.
(2) The eyeglass lens grinding apparatus according to (1), wherein the axis-to-axis distance detecting means includes a movement amount detecting means for detecting at least one of an amount of movement of the lens rotating shafts and an amount of movement of the abrasive wheel rotating shaft by the moving means.
(3) The eyeglass lens grinding apparatus according to (2), wherein the moving means includes a motor for moving at least one of the lens rotating shafts and the abrasive wheel rotating shaft, and the movement amount detecting means obtains the amount of the movement by detecting a rotational angle of the motor.
(4) The eyeglass lens grinding apparatus according to (1), wherein the control means varies processing pressure based on the result of detection by the axis-to-axis distance detecting means.
(5) The eyeglass lens grinding apparatus according to (4), wherein the moving means includes a motor for moving at least one of the lens rotating shafts and the abrasive wheel rotating shaft, and the control means varies rotational torque of the motor based on the result of detection by the axis-to-axis distance detecting means.
(6) The eyeglass lens grinding apparatus according to (1), further comprising:
processing data obtaining means for obtaining processing data based on shape data on eyeglass frame and layout data; and
processed condition detecting means for detecting processed condition of the lens based on the processing data obtained by the processing data obtaining means and the result of detection by the axis-to-axis distance detecting means,
wherein the control means controls the processing based on a result of detection by the processed condition detecting means.
(7) The eyeglass lens grinding apparatus according to (6), wherein the processed condition detecting means includes unprocessed amount detecting means for detecting an remaining amount of lens to be processed in relation to an angle of rotation of the lens.
(8) The eyeglass lens grinding apparatus according to (7), wherein the control means controls the lens rotating means based on the remaining amount thus obtained.
(9) The eyeglass lens grinding apparatus according to (8), wherein the control means controls lens rotating means so as to vary at least one of a rotating speed of the lens and a rotational direction of the lens.
(10) An eyeglass lens grinding apparatus for grinding a periphery of a lens, the apparatus comprising:
lens rotating shafts which holds and rotates the lens;
a lens rotating device which rotates the lens rotating shafts, the lens rotating device including a motor and a transmission member that transmits rotational force of the motor to the lens rotating shafts;
an abrasive wheel rotating shaft which rotates at least one lens grinding abrasive wheel;
an abrasive wheel rotating device which rotates the abrasive wheel rotating shaft, the abrasive wheel rotating device including a motor and a transmission member that transmits rotational force of the motor to the abrasive wheel rotating shaft;
a moving device which relatively moves the lens rotating shafts with respect to the abrasive wheel rotating shaft to thereby vary an axis-to-axis distance between the each of the lens rotating shafts and the abrasive wheel rotating shaft, the moving device including a moving motor;
an axis-to-axis distance detecting device which detects an angle of rotation of the moving motor, to thereby obtain the axis-to-axis distance varied by the moving device; and
a controller which controls processing based on a result of detection by the axis-to-axis distance detecting device.
(11) The eyeglass lens grinding apparatus according to (10), wherein the controller controls processing pressure by varying rotational torque of the moving motor based on the result of detection by the axis-to-axis distance detecting device.
(12) The eyeglass lens grinding apparatus according to (10), wherein the controller obtains processing data based on inputted eyeglass lens shape data and layout data, obtains an unprocessed amount of the lens in relation to an angle of rotation of the lens based on the processing data thus obtained and the result of detection by the axis-to-axis distance detecting device, and controls the lens rotating device based on the unprocessed amount thus obtained.
(13) The eyeglass lens grinding apparatus accord
Hail III Joseph J.
Nguyen George
Nidek Co. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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