Sewing Machine Needle Proximity Detection via Imaging
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Solution Overview
Problem
Existing sewing machines with safety covers face installation challenges, impede workability during maintenance, and have limited detection ranges for foreign objects, making them cumbersome, costly, and space-intensive.
Innovation Solution
A sewing machine configuration that includes a needle bar with a sewing needle, a vertical drive mechanism, an imaging unit to capture images of the needle and nearby objects, a distance or time calculating portion, and a control system to execute safety operations based on proximity judgments, allowing for wide-range detection and easy installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety cover is installed to cover the needle bar, then user safety is improved, but installation becomes cumbersome and workability deteriorates
Solution Approach 1:
The safety cover is designed to rotate between a retracted position (during sewing) and a covering position (during maintenance), making it dynamic rather than static. This allows the cover to adapt to different operational states, providing safety when needed and not impeding workability during maintenance operations like needle threading and presser foot replacement
2Measurement precision
If multiple pairs of light sensors are used to increase detection range, then foreign object detection capability is improved, but cost increases and device complexity worsens
Solution Approach 1:
The patent transitions from using multiple discrete light sensors (point detection) to a single line sensor that detects along an extended line (line detection). This dimensional change in detection capability allows a single sensor to cover the same detection range that would otherwise require multiple sensors, reducing both cost and complexity while maintaining or improving detection capability
3Ease of operation
If a safety cover is rotated to the retracted position, then accessibility is improved, but the cover still impedes needle threading and presser foot replacement
Solution Approach 1:
The safety cover is completely removed from the needle bar area during maintenance operations. The rotatable design allows the cover to be taken out of the way entirely (rotated to covering position) during needle threading and presser foot replacement, eliminating any impediment to these maintenance tasks while still providing safety coverage when rotated to the retracted position during sewing operations
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
Enhances user safety by reliably detecting foreign objects approaching the needle, improving workability, reducing costs, and enabling compact spacing with a single imaging unit.
Implementation Method 1
an imaging unit that captures image of at least the sewing needle and a moving object that is in close proximity of the sewing needle
Data Source
AI summary
A sewing machine including a needle bar that has a sewing needle attached in a lower end thereof; a needle-bar vertical drive mechanism that vertically moves the needle bar by a sewing machine motor via a sewing machine motor main shaft; an imaging unit that captures image of at least the sewing needle and a moving object that is in close proximity of the sewing needle; a distance calculating portion that calculates a distance between the sewing needle and the moving object based on image data captured by the imaging unit; a judging portion that makes a judgment that the distance calculated by the distance calculating portion is equal to or less than a predetermined distance; and a control portion that controls execution of a predetermined safety operation based on a judgment result of the judging portion.