Needle Plate Hole Design for Clean Cutting Surfaces

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Solution Overview

Problem

Existing sewing machines with circular needle plate holes often result in torn or rough-cut surfaces due to the rotation of the cutting needle, leading to suboptimal finish quality during cutting operations.

Innovation Solution

A needle plate with a hole configuration that includes a linear blade-side cutting side and a corresponding linear hole-side cutting side, along with a curved relief portion, allowing the cut target object to escape and improving the finish of the cut surface by enabling precise shearing and minimizing tearing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a circular needle plate hole is used to accommodate the rotating cutting needle, then the cutting needle can rotate freely, but the cutting target object may be torn off and the cut surface becomes rough

Engineering Contradiction:

Improvecutting needle rotationVSAvoidcut surface finish

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The needle plate hole is segmented into two distinct functional regions: a cutting side with a linear shape that works with the blade to shear the material, and a relief portion with a curved shape that allows the cut material to escape. This segmentation resolves the contradiction by providing both rotation accommodation and clean cutting surfaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the needle plate hole have different shapes and functions: the cutting side has a linear shape for precise shearing, while the relief portion has a curved shape for material egress. This local differentiation allows the hole to simultaneously enable needle rotation and produce smooth cut surfaces.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the cutting needle rotates around the needle bar axis, then the cutting direction changes according to rotation position, but this causes tearing and rough surfaces

Engineering Contradiction:

Improvecutting direction adjustmentVSAvoidcut surface finish

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The needle plate hole is divided into a cutting side and a relief portion, where the cutting side maintains a consistent linear orientation regardless of needle rotation. This allows the needle to rotate for different cutting directions while the linear cutting side ensures consistent, tear-free cutting performance.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11566358B2Needle plate and sewing machine including same

Publication Date: 2023.01.31 JANOME CORP

AI summary

In a needle plate, a needle plate hole is configured to include a hole-side cutting side that cuts a cutting target object together with a blade portion, and a relief side that allows a cut portion of the cutting target object to escape. Specifically, the needle plate hole has the hole-side cutting side that shears the cutting target object together with a blade-side cutting side of the blade portion, and the relief side that forms a gap between the blade portion to be inserted and the relief side. In this manner, in the former stage of cutting processing, the cutting target object can be cut by the hole-side cutting side and the blade-side cutting side.