Sewing Machine Needle Gap Adjustment via Screw Dial
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Solution Overview
Problem
Adjusting the needle gap between a sewing needle and a hook point in a sewing machine requires technical skill and experience, as it involves manual movement of parts without a tool, leading to potential inaccuracies in stitch formation.
Innovation Solution
A sewing machine design incorporating a needle bar base, a support shaft, an adjustment member, and an urging portion, where the adjustment member includes a screw portion and a contact portion, allowing for fine adjustment of the needle gap through a rotatable adjustment dial without the need for tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment of the holding shaft is performed by feel without tools, then the adjustment can be done without additional components, but the adjustment precision and reliability deteriorate due to lack of fine control
Solution Approach 1:
A dial indicator is introduced as an intermediary measurement tool between the operator and the needle gap adjustment. The dial indicator's probe contacts the needle bar base and converts small positional changes into readable dial movements, enabling precise measurement of the needle gap while maintaining tool-free operation for the operator.
Solution Approach 2:
The adjustment mechanism is transformed from purely manual mechanical feeling to a system that incorporates mechanical measurement (dial indicator) coupled with screw mechanism adjustment. This substitution allows visual and tactile feedback through the dial readings rather than relying solely on manual feel.
2Adaptability or versatility
If the holding shaft is moved slightly in the axial direction to adjust the needle gap, then the needle gap can be changed, but the adjustment becomes difficult to control precisely without technical skill
Solution Approach 1:
The dial indicator serves as a mediator that provides quantitative feedback during adjustment. The operator rotates the adjustment member while observing the dial indicator readings, which clearly show the magnitude and direction of needle gap changes, making the adjustment process intuitive and precise without requiring technical skill.
Solution Approach 2:
The dial indicator provides real-time feedback on the needle gap magnitude during adjustment. As the adjustment member is rotated and the needle bar base moves, the dial indicator immediately reflects the positional change, allowing the operator to stop at the desired gap value with precision.
3Reliability
If visual checking is used to monitor the gap between sewing needle and hook point during adjustment, then the gap can be observed, but the precision is limited by human visual acuity
Solution Approach 1:
Visual checking is supplemented and enhanced by replacing it with a mechanical measurement system (dial indicator). The dial indicator's probe physically contacts the needle bar base and translates small movements into amplified dial readings, providing measurement precision far beyond human visual acuity while maintaining reliability for stitch formation.
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
Enables easy and precise adjustment of the needle gap, improving stitch formation reliability and reducing the need for operator expertise, while maintaining a simple and cost-effective machine configuration.
Implementation Method 1
a compression coil spring that is surrounded by the support shaft and is in contact with the needle bar base and the base holder at the other ends respectively, wherein the compression coil spring urges the needle bar base toward the adjustment member
Implementation Method 2
The adjustment member is provided on the support shaft and is configured to move along an axial direction of the support shaft. The adjustment member includes a second screw portion and a first contact portion. The second screw portion is screwed into the first screw portion.
Data Source
AI summary
A sewing machine includes a needle bar base, a support shaft, an adjustment member, and an urging portion. The needle bar base has a through hole on an upper end portion. The support shaft is inserted through the through hole and pivotably supports the needle bar base. The support shaft includes a leading end portion. The leading end portion includes a first screw portion. The adjustment member is provided on the support shaft and is configured to move along an axial direction of the support shaft. The adjustment member includes a second screw portion and a first contact portion. The second screw portion is screwed into the first screw portion. The first contact portion is in contact with the needle bar base. The urging portion urges the needle bar base toward the first contact portion of the adjustment member.