Sewing Machine Speed Feedback for Consistent Stitch Pitch

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Solution Overview

Problem

Conventional sewing machines fail to maintain a designated sewing pitch when a user moves the material to be sewn too fast, leading to uneven stitching due to inadequate follow-up control of the sewing speed.

Innovation Solution

A sewing machine equipped with a movement detection unit, control unit, and informing component that calculates and displays the rotational rate of the sewing machine motor relative to a maximum rate, allowing users to adjust their movement speed to maintain a stable sewing pitch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the user moves the material faster to increase productivity, then the sewing speed increases, but the sewing pitch becomes uneven and follows the material movement inaccurately

Engineering Contradiction:

Improvesewing speedVSAvoidsewing pitch accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The informing component provides real-time feedback to the user about the rotational rate of the sewing machine motor. This feedback loop allows the user to adjust their material movement speed to maintain the desired sewing pitch, resolving the contradiction between high productivity and precise sewing pitch control.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the detection period is adjusted to reduce noise effect, then the movement detection accuracy improves, but the follow-up control still fails when material moves too fast

Engineering Contradiction:

Improvemovement detection accuracyVSAvoidmaterial movement speed limit

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The informing component acts as an intermediary between the movement detection unit and the user. It translates the detected material movement speed into an understandable rotational rate indicator, enabling the user to consciously adjust their movement speed to stay within the optimal range for accurate follow-up control.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the sewing machine motor operates at maximum rotational rate to maintain sewing pitch, then the sewing pitch accuracy is maintained, but the user has no means to grasp the current sewing speed

Engineering Contradiction:

Improvesewing pitch consistencyVSAvoiduser awareness of sewing speed

Core Design Contradiction:

Manufacturing precisionVSLoss of information

Solution Approach 1:

The informing component provides continuous feedback to the user about the current rotational rate relative to the maximum rotational rate. This information feedback enables the user to understand the current sewing speed and adjust material movement accordingly, preventing loss of information about sewing parameters.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12480241B2Sewing machine

Publication Date: 2025.11.25 JANOME CORP

AI summary

A sewing machine includes a sewing pitch setup unit configured to set up a given sewing pitch; a movement detection unit configured to detect a movement of a material to be sewn; a control unit configured to calculate a movement speed of the material on the basis of a movement amount of the material detected by the movement detection unit and to calculate a rotational rate for a sewing machine motor for operating a needle on the basis of the movement speed and the given sewing pitch; and an informing component configured to inform of magnitude of the rotational rate relative to a maximum rotational rate for the sewing machine motor.