Sewing Machine Skip Checker Using Pneumatic Thread Curving
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Solution Overview
Problem
Existing skip stitch detection systems for sewing machines are structurally complex and costly, leading to unstable accuracy in detecting skip stitches and thread disconnections, which affects sewing efficiency, especially in mass production.
Innovation Solution
An automated skip checker device with a simplified structure that uses a tension provider, such as a pneumatic air stream or torsional spring, to detect slack in the sewing thread, combined with an optical or proximity sensor to accurately identify the position and length of slack, thereby determining the presence of skip stitches or thread disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sound sensor or rotary sensor is used to detect skip stitches by comparing frictional noise or revolution differences, then skip stitch detection capability is achieved, but device complexity increases and detection accuracy becomes unstable
Solution Approach 1:
The patent extracts the detection function from complex sensor systems (sound sensors, rotary sensors) and implements it through a simple optical sensor that detects thread position directly. This removes unnecessary complexity while maintaining detection capability.
Solution Approach 2:
The patent replaces mechanical detection methods (sound sensors, rotary sensors) with an optical detection system. The optical sensor detects thread position through light interruption, substituting mechanical measurement with optical measurement for simpler and more reliable detection.
2Reliability
If strain gauge is used to detect thread tension through sliding pressure against guide ring, then thread disconnection detection is achieved, but detection accuracy becomes unstable due to varying sliding pressure
Solution Approach 1:
The patent replaces the strain gauge mechanical measurement system with an optical detection system. Instead of measuring tension through sliding pressure, the optical sensor detects thread position changes, providing more stable and accurate detection不受 varying friction conditions.
3Extent of automation
If predetermined threshold values are used to distinguish skip stitches based on frictional noise duration or revolution differences, then automated detection is achieved, but detection accuracy becomes unstable when sewing conditions change
Solution Approach 1:
The patent implements dynamic detection by continuously monitoring thread position and comparing consecutive positions to detect slacked portions. Instead of using fixed thresholds, the system adapts to varying sewing conditions through real-time position comparison, maintaining accurate detection across different cloth materials and sewing parameters.
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 solution provides high accuracy and cost-effectiveness in detecting skip stitches and thread disconnections, improving sewing efficiency and reducing the need for frequent adjustments based on cloth material variations.
Implementation Method 1
The tension provider is an air stream provider which continuously gives a pneumatic pressure to the sewing thread.
Implementation Method 2
the detection member is an optical sensor having a light emitting element and a photo element to detect the slack appeared on the sewing thread
Data Source
AI summary
In an automated skip checker device for sewing machine 1, a detector device 8 detects a slack portion 3a of a predetermined length D. The slack portion 3a definitely corresponds to a skip of a stitch or a disconnection of a sewing thread so as to unerringly carry out the detection with a high accuracy. The detector device 8 of the skip checker device has an air stream provider 19 which transfers a tension to an upper thread 3 as a pneumatic pressure to energize an optoelectronic switch 23 so as to make the detector device 8 structurally compact and cost-saving.