Circular Knitting Drive Chain with Elastic Butt Retraction

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Solution Overview

Problem

Circular knitting machines experience issues with drive chain butts breaking or being damaged due to incorrect interactions with cams, leading to machine downtime and reduced productivity, and existing drive chains have limited selection accuracy despite compact size.

Innovation Solution

A drive chain design featuring an oscillating lever with an elastic joint and a first butt that can embed into a groove during interference, preventing damage and allowing for higher selection accuracy without increasing the chain's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed butt is used in the drive chain, then the structure is simple and compact, but the butt breaks or damages due to incorrect interaction with cams

Engineering Contradiction:
Improvedrive chain structureVSAvoidbutt durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies the dynamics principle by transforming the fixed butt into a movable butt that can oscillate between a protruding position (for normal operation) and a retracted position (for interference protection). The movable butt is connected to the needle via an oscillating lever that pivots about an axis, allowing the butt to dynamically adjust its position based on operational conditions. This dynamic structure prevents breakage by automatically retracting when interference with cams is detected, while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the butt is made movable to prevent breaking, then reliability improves, but the selection accuracy decreases

Engineering Contradiction:
Improvebutt durabilityVSAvoidselection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the drive chain into distinct functional segments: the needle, the oscillating lever, and the movable butt. The oscillating lever acts as an intermediary segment that connects the needle to the movable butt, allowing independent optimization of each component. The lever's pivot point is strategically positioned to ensure that the movable butt's oscillation range is sufficient for protection but minimal enough to maintain selection accuracy. This segmented structure enables the system to achieve both reliability and precision.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If the oscillating lever length is increased to improve selection accuracy, then selection accuracy improves, but the drive chain size increases

Engineering Contradiction:
Improveselection accuracyVSAvoiddrive chain size
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The patent applies partial action by providing just enough oscillating lever length to achieve the required selection accuracy and protection function, without excessive length that would increase drive chain size. The lever is designed with minimal sufficient dimensions to allow the movable butt to retract adequately during interference while maintaining compact overall structure. This optimized dimensioning ensures the drive chain remains compact while achieving the necessary performance.

Inventive Principle:
Principle #16Partial or excessive action

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

The design enhances safety and reliability, reduces maintenance costs, and increases productivity by preventing butt damage and improving selection accuracy, while maintaining the chain's overall size.

Implementation Method 1

the first portion (9) is elastically coupled with the second portion (10) so as to keep the first butt (18) in an operating position in which said butt protrudes from the groove and to allow the first butt (18) to get back into the groove in case of interference with one of the first actuating cams (25)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4413191B1A drive chain for stitch formation members of a circular knitting machine and a circular knitting machine comprising such drive chain
Publication Date: 2025.07.02 SANTONI SPA
  • EP4413191B1 patent drawingFigure 1
  • EP4413191B1 patent drawingFigure 2
  • EP4413191B1 patent drawingFigure 3

AI summary

A drive chain for stitch formation members of a circular knitting machine comprises an element (6) coupled or to be coupled with a stitch formation member, and an oscillating lever (7) connected to said element (6) on a junction area. The oscillating lever (7) is configured for interacting with selecting devices (23) so as to oscillate with respect to said element (6). Said element (6) comprises a first portion (9) carrying a first butt (18) and a second portion (10) configured for slidingly coupling with a bottom of a respective groove (5). The first portion (9) is elastically coupled with the second portion (10) so as to keep the first butt (18) in an operating position in which the first butt (18) protrudes from the groove (5), and to allow the first butt (18) to get back into the groove (5) in case of interference with one of the first actuating cams (25).