Circular Knitting Machine Needle Drive Chain Radial Butt Control

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Solution Overview

Problem

Existing circular knitting machines face limitations in size, movement flexibility, and yarn feeding capacity, particularly for machines with small diameters, leading to restricted production capabilities and increased inertia, which hinders the production of diverse fabrics and faster knitting speeds.

Innovation Solution

A circular knitting machine design featuring a drive chain with a sub-needle, punch, selector, and activating element that allows independent axial movement of the activating element relative to the punch and selector, enabling more nuanced and flexible needle movements, including radial extraction and insertion, decoupling axial movements from needle activation, and utilizing elastic elements for safer and more effective butt movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the diameter of the needle-holding cylinder is reduced to manufacture smaller fabrics, then the machine size is reduced, but the number of feeds (yarn feeding points) that can be introduced is limited due to insufficient space around the cylinder

Engineering Contradiction:
Improvemachine sizeVSAvoidnumber of feeds
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The actuating means for each needle is divided into separate functional elements: a sub-needle with radially moving butt, a punch, a selector, and an activating element. This segmentation allows each component to perform specific functions independently, enabling compact arrangement around the needle-holding cylinder while maintaining multiple feed capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes radial movement of the butt of the sub-needle perpendicular to the axial direction of the needle-holding cylinder. This radial dimension provides an additional degree of freedom for needle activation without increasing the axial space required, allowing more feeds to be accommodated around smaller diameter cylinders.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the number of feeds is increased in machines with small diameter needle-holding cylinders, then yarn feeding capacity is improved, but the axial and circumferential space requirements cannot be met

Engineering Contradiction:
Improveyarn feeding capacityVSAvoidspace around cylinder
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The actuating components are nested within the axial grooves of the needle-holding cylinder. The selector, punch, and sub-needle are arranged concentrically and axially within the same groove space, maximizing the use of available volume without requiring additional circumferential or axial space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The butt of the sub-needle is designed to move radially between engaged and disengaged positions, allowing dynamic control of needle activation. This dynamic mechanism enables multiple feed points to share the same circumferential space by activating different needles at different times through radial movement.

Inventive Principle:
Principle #15Dynamics

3Speed

If the machine diameter is reduced to decrease inertia and increase rotational speed, then knitting speed is improved, but the space for housing actuating means becomes insufficient

Engineering Contradiction:
Improverotational speedVSAvoidactuating means arrangement
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

Multiple actuating functions are merged into a single integrated drive chain per needle: the selector, punch, and sub-needle with radially moving butt work together as one coordinated unit within the axial groove. This merging reduces the total number of separate mechanisms required and allows compact packaging in smaller diameter machines.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If known actuating means are used in small diameter machines, then manufacturing is simplified, but needle movement flexibility is limited

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidneedle movement flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The sub-needle with radially moving butt acts as an intermediary between the punch and the needle. This intermediary element provides an additional degree of freedom for needle activation, enabling complex needle movements and fabric patterns while maintaining a relatively simple overall structure that is manufacturable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3615723B1A circular knitting machine and a method for moving the needles of a circular knitting machine
Publication Date: 2021.06.23 SANTONI SPA
  • EP3615723B1 patent drawingFigure 1
  • EP3615723B1 patent drawingFigure 2a
  • EP3615723B1 patent drawingFigure 2b

AI summary

A circular knitting machine comprises a needle-holding cylinder (2) having a plurality of longitudinal grooves (4) arranged around a central axis (X-X), and a plurality of needles (3), each being housed in a respective longitudinal groove (4). A drive chain (5) for each needle (3) is inserted into each longitudinal groove (4), is located below the respective needle (3) and is operatively placed between the respective needle (3) and actuating cams (C). The drive chain (5) comprises a sub-needle (6) slidingly arranged in the respective longitudinal groove (4) below the needle (3) and having a butt (19), wherein the butt (19) is radially movable between an operating position, in which it is extracted so as to engage with respective first paths defined by first actuating cams (39) and cause the activation of the needle (3) and the stitch formation, and a non-operating position, in which it is retracted so as not to engage with said first paths (inactive needle). A selector (9) is arranged under the sub-needle (3) and a punch (7) is arranged between the sub-needle (6) and the selector (9). An activating element (8) is slidingly arranged in the respective longitudinal groove (4) between the sub-needle (6) and the selector (9), can be longitudinally moved with respect to the punch (7) and with respect to the sub-needle (6) and can be operatively engaged with the sub-needle (6) so as to switch the butt (19) of the sub-needle (6) into and retain it in the respective operating position.