Differential Feeding Lasting Machine for Consistent Stitch Lengths
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Solution Overview
Problem
Existing lasting machines for sewing insoles and uppers result in uneven stitch lengths due to the inability of the presser foot wheel to rotate independently, leading to operator fatigue and inconsistent stitching, especially when dealing with curved surfaces.
Innovation Solution
A differential feeding lasting machine with a mechanism that allows the rotation speed of the feed wheel to be adjusted independently of the presser foot wheel, using a control system with sensors and gear sets to maintain consistent stitch lengths across different areas by varying the swing amplitude of the swing arm and the rotation speed of the presser foot wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the presser foot wheel is driven by a stepping motor to rotate independently, then operator hand injury is avoided and stitching automation is improved, but stitch length uniformity deteriorates when rotation speed difference is too large or friction resistance is high
Solution Approach 1:
The patent employs a differential feeding mechanism where the presser foot wheel and feed wheel can rotate at different speeds dynamically adjusted during the stitching process. The presser foot wheel is driven by a stepping motor that can independently control its rotation speed to match the feed wheel's speed, ensuring uniform stitch length while maintaining automated operation and preventing operator hand injury.
Solution Approach 2:
The system changes the rotation speed parameter of the presser foot wheel dynamically during operation. The stepping motor controlling the presser foot wheel can adjust its rotation speed to match the feed wheel's speed, compensating for friction resistance and contour variations to maintain consistent stitch length across different stitching conditions.
2Manufacturing precision
If the presser foot wheel rotates at different speed from the feed wheel to maintain stitch length, then stitch uniformity is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent incorporates a feedback control mechanism where sensors detect the rotation positions of both the feed wheel and presser foot wheel, and the control system adjusts the stepping motor's rotation to maintain the correct speed relationship. This feedback loop ensures stitch length consistency while automating the speed coordination, making the increased device complexity worthwhile for achieving uniform stitching.
Solution Approach 2:
The control mechanism serves multiple functions: it controls the stepping motor that drives the presser foot wheel, coordinates the rotation speeds of both wheels, and maintains stitch length uniformity. By making the control system multi-functional, the patent reduces overall device complexity while achieving the desired stitch consistency.
3Stability of the object's composition
If the feed wheel and presser foot wheel are clamped together to hold the insole and upper, then stitching stability is maintained, but operator hands must grip the materials causing injury
Solution Approach 1:
The patent makes the presser foot wheel self-driven through the stepping motor, allowing it to rotate independently to feed the materials through the stitching process. This self-service capability eliminates the need for operator hands to grip and manually feed the insole and upper, preventing hand injuries while maintaining stitching stability through coordinated wheel rotation.
Data Source
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AI summary
The present disclosure provides a differential feeding lasting machine which comprises: a body, a feeding mechanism, a presser foot mechanism, an adjusting mechanism and a control mechanism. The body has a swing arm, and the feeding mechanism has a feeding wheel. The presser foot mechanism has a presser foot wheel, and the adjusting mechanism has an adjustment driving source and an adjustment transmission assembly. The adjustment driving source rotate according to several rotation angles, which makes the adjustment transmission assembly move relative to the swing arm for adjusting the rotation amount of the feeding wheel, and the control mechanism can control the rotation speed of both the presser foot wheel and the feeding wheel. Accordingly, the adjusting mechanism can adjust the rotation speed of the feeding wheel relative to the presser foot wheel, and thus each stitch formed in the insole and the upper can keep a similar stitch length.