Adjustable Presser Foot Knife for Fabric Overlap Control
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Solution Overview
Problem
Conventional sewing machines with presser feet struggle to maintain a proper overlapped width of fabrics during seaming, leading to defective seams due to variations in fabric type, such as stretchable or soft fabrics, resulting in reduced sewing strength and poor fit.
Innovation Solution
A presser foot with a position adjusting unit that allows for vertical adjustment of the fixed knife, enabling precise control over the cut position of fabric ends and overlapped width, using a guide hole and stop screw mechanism for easy adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed knife position is used in the presser foot, then the structure is simple, but the overlapped width of fabrics cannot be adjusted for different fabric types
Solution Approach 1:
The fixed knife is made adjustable through a position adjusting unit that allows vertical movement along the presser leg. This transforms the static knife position into a dynamic, adjustable one, enabling adaptation to different fabric types while maintaining structural simplicity through a straightforward adjustment mechanism.
Solution Approach 2:
The vertical position of the fixed knife is changed as a adjustable parameter. By modifying the position parameter of the fixed knife relative to the movable knife, the overlapped width of fabrics can be controlled, allowing the same device to handle different fabric types effectively.
2Manufacturing precision
If the fixed knife position is adjustable, then the overlapped width can be controlled precisely, but the adjustment mechanism increases device complexity
Solution Approach 1:
The adjustment mechanism is segmented into distinct components: a position adjusting unit with a guide hole for vertical movement, and a stop screw for securing the position. This segmentation allows for precise control of the fixed knife position while keeping each component simple and easy to manufacture.
Solution Approach 2:
The guide hole acts as an intermediary element that guides the vertical movement of the fixed knife, ensuring precise positioning. The stop screw serves as another intermediary that secures the knife at the desired position, providing precise control without requiring a complex adjustment system.
3Adaptability or versatility
If the fixed knife is fixed vertically, then the structure is stable, but it cannot adapt to variations in fabric type requiring different overlapped widths
Solution Approach 1:
The fixed knife is transformed from a static component to a dynamically adjustable one. The position adjusting unit allows the knife to be moved vertically to different positions, providing adaptability to various fabric types while maintaining structural stability when positioned and secured.
Solution Approach 2:
The operator can preliminarily adjust the fixed knife position before sewing different fabric types. This preliminary adjustment ensures that the correct overlapped width is set in advance, allowing the structure to remain stable during the actual sewing process while being adaptable to different requirements.
Data Source
AI summary
In a presser foot and a sewing machine according to the present invention, a guide hole is formed in a presser leg to which a fixed knife is attached, so as to passing through the presser leg up and down, and a knife holder is fitted and held to the guide hole. The fixed knife is inserted to a retention groove provided in a peripheral surface of the knife holder through a window hole provided in the presser leg, and is fixed by fastening a stop screw. A position of the fixed knife is adjusted in a vertical direction by moving the knife holder in the vertical direction along the guide hole and fastening the stop screw at an appropriate position, thereby changing a cut position of ends of fabrics and changing an overlapped width of the fabrics at a time of seaming.