Optical Lace Position Sensing for Reliable Tension Control
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Solution Overview
Problem
Existing motorized lacing systems for footwear lack a reliable mechanism to determine the actual state of the laces, leading to potential over-tightening or loosening beyond the wearer's comfort level, as the motor controller may enter an indeterminate state.
Innovation Solution
A position sensing assembly is integrated into the tensioning system, utilizing an indicator tab on a lead screw that indicates the lace state, detected by an optical sensing unit, ensuring consistent control of lace tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motorized tensioning device is used to wind and unwind the tensioning member, then the tensioning system can achieve incremental tightening and loosening, but the system lacks reliable position feedback leading to indeterminate motor controller states and potential over-tightening or loosening
Solution Approach 1:
The patent implements feedback by using an optical sensing unit to detect the position of an indicator tab that is mechanically coupled to the spool. This provides continuous position feedback to the motor controller, enabling it to determine the actual state of the tensioning member and prevent indeterminate states. The feedback mechanism allows the system to know when the tensioning member is fully wound or unwound, resolving the reliability issue.
Solution Approach 2:
The patent introduces an indicator tab as an intermediary element that mechanically couples the spool position to the optical sensing unit. This intermediary translates the rotational position of the spool into a detectable linear or angular displacement that the optical sensor can reliably measure, providing the motor controller with accurate position information without requiring direct measurement of the spool's rotational state.
2Device complexity
If no position sensing mechanism is implemented, then the device complexity is reduced, but the lace tension control precision deteriorates leading to over-tightening or loosening
Solution Approach 1:
The patent replaces complex mechanical position sensing mechanisms with an optical sensing system. Instead of using encoders, potentiometers, or other mechanical sensors that would add complexity, the system uses a simple optical sensor to detect the position of the indicator tab. This substitution maintains high tension control precision while minimizing the addition of complex mechanical components.
Solution Approach 2:
The indicator tab serves multiple functions: it acts as a mechanical coupling element between the spool and the optical sensor, serves as the target for optical detection, and provides positional information for both tightening and loosening operations. This multi-functionality reduces the need for separate components and simplifies the overall sensing assembly.
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 position sensing assembly provides precise control over lace tension, preventing over-tightening or loosening, thereby enhancing wearer comfort and consistency in lace management.
Implementation Method 1
an optical sensing unit disposed adjacent the lead screw and configured to detect a position of the indicator tab
Data Source
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AI summary
A position sensing assembly for a tensioning system designed to provide tension to a lace, cord, or other type of strand is disclosed. The tensioning system includes a reel member configured to rotate about a central axis and the position sensing assembly. The position sensing assembly includes a shaft, an indicator tab, and an optical sensing unit. The position sensing assembly assists in controlling the degree to which the strand is tightened and loosened. The position sensing assembly prevents tightening of the strand when the strand is meant to be loosened.