Randomized Stitch State Assignment for Medical Compression Garments

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Solution Overview

Problem

Current knitting machines used for manufacturing medical compression garments are limited in producing fabrics that meet normative requirements for comfort and durability, particularly in achieving bulky thickness and avoiding structural instabilities associated with rib patterns.

Innovation Solution

A method of randomly assigning states to stitches within a predefined range to create a fabric with a fuzzy appearance and increased durability, using existing knitting machines and yarns, which eliminates the optical and physical rib effect and ensures compliance with normative specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If rib patterns are used to increase fabric thickness and comfort, then wear comfort is improved, but structural instabilities occur in the fabric

Engineering Contradiction:
Improvewear comfortVSAvoidfabric structural stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies asymmetry by breaking the periodic symmetry of traditional rib patterns. Instead of repeating the same stitch pattern at regular intervals, the invention uses randomized stitch states that prevent predictable periodic structures, thereby eliminating the structural instabilities associated with conventional rib patterns while maintaining fabric thickness and comfort.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the parameter of stitch pattern regularity from fixed (in traditional rib patterns) to randomized (in the invention). By controlling the probability distribution of stitch states rather than using deterministic patterns, the fabric achieves bulky thickness similar to rib patterns without the associated structural instabilities.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If terry-loop pattern is used to achieve bulky fabric thickness, then wear comfort is improved, but it cannot be manufactured with currently available knitting machines

Engineering Contradiction:
Improvewear comfortVSAvoidmanufacturability with existing machines
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent changes the manufacturing approach by modifying the stitch pattern parameters rather than changing the machine hardware. By using randomized stitch assignment within the capabilities of existing 20-32 needles per inch knitting machines, the invention achieves terry-loop-like bulky fabric thickness without requiring specialized equipment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a copy of the terry-loop pattern's visual and tactile effects through randomized stitching, without replicating the exact terry-loop structure. This allows existing knitting machines to produce fabric with similar comfort properties to terry-loop patterns while avoiding the manufacturing complexity of actual terry-loops.

Inventive Principle:
Principle #26Copying

3Shape

If random stitch patterns are used to eliminate rib effects, then appearance is improved, but fabric thickness may be reduced

Engineering Contradiction:
Improvefabric appearanceVSAvoidfabric thickness
Core Design Contradiction:
ShapeVSVolume of moving object

Solution Approach 1:

The patent carefully controls the probability parameters of random stitch assignment to maintain fabric thickness. By adjusting the probability distribution of stitch states and using multiple yarn layers, the invention achieves the desired appearance without sacrificing the bulky volume needed for comfort and functionality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1878822B1Method for manufacturing a medical compression garment comprising the assignement of states to stitches of a fabric
Publication Date: 2009.11.11 GANZONI MANAGEMENT
  • EP1878822B1 patent drawingFigure 1~2
  • EP1878822B1 patent drawingFigure 3~4
  • EP1878822B1 patent drawingFigure 5~6

AI summary

The present invention relates to a method for assigning states to stitches of a fabric, wherein the state can vary between a first and a second state, that comprising the steps of a) allocating a part of the fabric (30), b) randomly assigning a state to each stitch of the allocated part of the fabric (31), c) evaluating the ratio between the number of stitches in the first state and the number of stitches in the second state (32), d) checking if the ratio lies within a predefined range of values (32), and e) restarting at step b) if the ratio lies outside the predefined range. The method may be used for manufacturing a medical compression garment.