Sewing Machine Presser Foot Pressure Control for Curved Seams
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Solution Overview
Problem
Existing sewing machines form curved seams on articles, which can lead to sewing defects such as pleats and fabric bending due to excessive pressure from the presser foot member.
Innovation Solution
A sewing machine with a pressure adjustment mechanism that adjusts the pressure of the presser foot member based on the difference in feeding amounts of belts on either side of the sewing position, and a control system to manage this pressure to match the belt feeding discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the pressure of the presser foot member is increased to stabilize the to-be-sewn article during curved seam formation, then the article stability is improved, but sewing defects such as pleats and fabric bending occur
Solution Approach 1:
The pressurizing force of the presser foot member is made dynamically adjustable rather than fixed. The control portion varies the pressure in real-time based on the curvature radius of the seam being formed, applying higher pressure for straight seams and lower pressure for curved seams, thus preventing fabric damage while maintaining stability when needed
Solution Approach 2:
The physical parameter of pressurizing force is changed according to the sewing conditions. By adjusting the pressure parameter based on the curvature radius, the system adapts the presser foot's force output to match the specific requirements of each sewing segment, avoiding excessive pressure that causes defects
2Shape
If the feeding amount of feeding belts is increased on one side to form a curved seam, then the seam curvature is achieved, but the pressure balance is disrupted causing sewing defects
Solution Approach 1:
The feeding amounts of the feeding belts on opposite sides are made asymmetric to achieve curved seam formation. The control portion independently controls each side's feeding amount, creating intentional asymmetry that produces the desired curve while coordinating with pressure adjustment to prevent defects
Solution Approach 2:
The control portion uses feedback from the curvature radius information to coordinate both feeding amount adjustments and pressure adjustments. By continuously monitoring the required curvature and adjusting both parameters accordingly, the system maintains sewing quality while achieving the desired seam shape
Data Source
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AI summary
A sewing machine that suppresses sewing defects is provided. The sewing machine includes: a sewing needing, held by a needle bar and moving back and forth while holding an upper thread; a shuttle, configured to hold a bobbin which is housed in a bobbin case and around which a lower thread is wound, and cooperating with the sewing needle to form a seam; a presser foot member, configured to press a to-be-sewn article at a sewing position directly below the sewing needle; a pressure adjustment portion, adjusting pressure applied to the to-be-sewn article by the presser foot member; a feeding mechanism, where endless feeding belts for feeding the to-be-sewn article from the sewing position to a first direction are disposed on two sides of a second direction orthogonal to a first direction with respect to the sewing position, the feeding mechanism is provided with a belt drive portion, and the belt drive portion independently drives the feeding belts on one side of the second direction with respect to the sewing position and the feeding belts on another side of the second direction with respect to the sewing position; and a control portion, configured to control the pressure adjustment portion to make a pressure of the presser foot member be corresponding to a difference between a feeding amount of the feeding belts on one side of the second direction with respect to the sewing position and a feeding amount of the feeding belts on another side of the second direction with respect to the sewing position.