Eyeglass Lens Processing Torque Control
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Solution Overview
Problem
Eyeglass lens processing apparatuses face challenges in reducing axial deviation and processing sound during roughing, particularly with water-repellent lenses, where existing methods either fail to control torque effectively or prolong processing time due to uncertainties in lens thickness and astigmatic variations.
Innovation Solution
An eyeglass lens processing apparatus with a mode selector that switches between normal and soft processing modes, using sensors to detect torque and adjust axis-to-axis distance and rotation speed to maintain a predetermined cutting amount, thereby reducing axial deviation and processing sound by controlling the cutting amount dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the up-cut system is adopted to reduce processing sound, then processing sound is reduced, but axial deviation is greatly generated due to increased pulling force on the lens
Solution Approach 1:
The patent applies dynamics by making the axis-to-axis distance between the lens chuck shaft and grindstone spindle variable rather than fixed. The distance is dynamically adjusted based on detected torque values - when torque exceeds a threshold, the distance is increased to reduce cutting amount and torque, and when torque is below the threshold, the distance is decreased to increase cutting amount. This dynamic adjustment resolves the contradiction by allowing the system to operate in up-cut mode (reducing sound) while compensating for axial deviation through real-time distance modulation.
Solution Approach 2:
The patent implements feedback control by detecting the torque applied to the lens chuck shaft during roughing and using this information to adjust the axis-to-axis distance. The torque detector continuously monitors the torque, and when it exceeds a predetermined threshold, the system responds by increasing the distance to reduce the cutting amount and torque. This closed-loop feedback mechanism enables the system to maintain stable operation in the up-cut system while preventing excessive axial deviation by actively responding to torque variations.
2Manufacturing precision
If the down-cut system is adopted to reduce axial deviation, then axial deviation is reduced, but processing sound becomes larger
Solution Approach 1:
The patent transforms the static down-cut system into a dynamic system where the axis-to-axis distance is continuously adjustable. By detecting torque and dynamically modifying the distance, the system can operate with characteristics closer to the up-cut system (reducing sound) while maintaining the precision benefits of the down-cut system through active compensation. The dynamic distance adjustment allows the system to achieve low sound levels without sacrificing axial alignment precision.
Solution Approach 2:
The patent changes the parameter of axis-to-axis distance from a fixed value to a variable parameter that is continuously adjusted based on torque detection. This parameter change enables the system to adapt its cutting characteristics in real-time, allowing operation in the quieter up-cut mode while compensating for the resulting axial deviation through precise distance modulation. The variable distance parameter becomes the key to resolving the sound-precision contradiction.
3Reliability
If lens rotation speed is decelerated to control torque in water-repellent lenses, then torque is controlled, but processing time is lengthened and control becomes difficult
Solution Approach 1:
Instead of statically decelerating the lens rotation speed, the patent dynamically adjusts the axis-to-axis distance based on torque detection. This dynamic approach allows the system to maintain higher rotation speeds (reducing processing time) while achieving effective torque control through real-time distance modulation. The system responds to torque variations by adjusting distance rather than speed, preserving both reliability and efficiency.
Solution Approach 2:
The patent substitutes the mechanical approach of speed control with a positional control approach. Instead of using variable speed drives to control torque, the system uses torque detection combined with dynamic distance adjustment. This substitution replaces the need for complex speed modulation with a more straightforward positional control mechanism, reducing processing time while maintaining torque reliability.
4Reliability
If axis-to-axis distance is increased to reduce torque, then torque is reduced, but lens chuck shaft vibration occurs and cutting amount decreases
Solution Approach 1:
The patent implements dynamic distance adjustment rather than static distance increase. The axis-to-axis distance is continuously modulated based on real-time torque detection, allowing the system to achieve torque control with minimal distance changes. This dynamic approach prevents excessive distance increase that would cause vibration and reduce cutting amount, while still maintaining effective torque control through precise, responsive adjustments.
Solution Approach 2:
The patent changes the distance parameter from a static increased value to a dynamically optimized value. Rather than permanently increasing the axis-to-axis distance, the system adjusts the distance parameter in real-time based on torque conditions. This parameter optimization allows torque control to be achieved with minimal distance changes, preserving cutting amount and preventing vibration while maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively reduces axial deviation and processing sound by dynamically adjusting cutting parameters, ensuring stable torque control and efficient processing even with water-repellent lenses and astigmatic variations, while shortening processing time.
Implementation Method 1
a sensor unit which includes a sensor for detecting a torque applied to the lens chuck shaft at the time of roughing of the lens by the roughing grindstone
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An eyeglass lens processing apparatus includes a processing control unit (50) which in the soft processing mode, sets a torque threshold value to a value Tθs lower than a value TθN of a normal processing mode, and when torque detected by a sensor unit (120a,50) does not exceed the value Tθs, a axis-to-axis distance varying unit (101,150) or a lens rotating unit is controlled so that a cutting amount per rotation of the lens reaches a predetermined cutting amount, and when the detected torque exceeds the value Tθs, controls the axis-to-axis distance varying unit or the lens rotating unit so that the torque becomes lower than the value Tθs to decrease the cutting amount.