Circular Knitting Machine Needle Actuation Cam Simplification

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Solution Overview

Problem

Current circular knitting machines for hosiery are complex due to the need for multiple movable cams, which increases the structure's complexity and requires additional actuation programs to manage their position during power interruptions, limiting the machine's design and operation.

Innovation Solution

A circular knitting machine design that simplifies the set of needle or slider actuation cams by using a connecting element with a movable heel that oscillates between active and inactive positions, eliminating the need for additional movable cams, and incorporating a selector to transfer the heel between actuation paths, allowing for various knitting types without additional movable cams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple movable cams are used to actuate needles and sliders in circular knitting machines, then the machine can perform various knitting types, but the structure becomes more complex and requires additional actuation programs to manage cam positions during power interruptions

Engineering Contradiction:
Improvecapability to perform various knitting typesVSAvoidstructure complexity and actuation program requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the movable cam mechanism from the system and replaces it with fixed cams. The selection of different knitting patterns is achieved not by moving cams but by selectively engaging or disengaging needle actuation elements from fixed cam paths, thereby eliminating the complexity of managing multiple movable cams while preserving pattern versatility

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of moving the cams to select different knitting patterns (conventional approach), the patent inverts the approach by keeping cams fixed and moving the needle actuation elements between different cam paths. This inversion simplifies the overall structure while maintaining the ability to perform various knitting types

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If movable cams are used to enable needle actuation for different knitting patterns, then knitting versatility is achieved, but the risk of mechanical damage during power interruptions increases

Engineering Contradiction:
Improveknitting pattern varietyVSAvoidrisk of mechanical damage during power interruptions
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent designs the system with fixed cams that have predetermined, safe engagement paths. The needle actuation elements are equipped with selectors that can be positioned in advance to engage only with fixed cam paths designed to return needles to safe positions, thereby cushioning against potential mechanical damage during unexpected power interruptions

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If traditional needle actuation mechanisms are used, then reliable needle control is achieved, but the structure requires multiple movable cams increasing device complexity

Engineering Contradiction:
Improveneedle control reliabilityVSAvoidnumber of movable cams
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the movable cam components from the traditional needle actuation mechanism and replaces them with fixed cams. The reliability of needle control is maintained through precise geometric design of the fixed cam paths and the selector mechanism that ensures proper engagement, while the complexity is reduced by eliminating movable cam assemblies

Inventive Principle:
Principle #2Taking out (Extraction)

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 machine achieves simplified actuation cam structures while maintaining the capability to perform traditional knitting types, ensuring precise operation at high speeds and reducing the risk of mechanical damage during power interruptions.

Implementation Method 1

said connecting element being able to oscillate on a radial plane of the needle cylinder for the transfer of said movable heel from an active position to an inactive position

Methodology Applied
Scientific EffectOscillation: Harmonic Oscillator

Implementation Method 2

said movable heel protruding radially from the corresponding axial slot of the needle cylinder to engage corresponding cams for actuating the connecting elements which face the lateral surface of the needle cylinder and define paths which can be followed by said movable heel

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2002040B1Circular knitting machine for hosiery
Publication Date: 2014.06.04 LONATI
  • EP2002040B1 patent drawingFigure 1~2
  • EP2002040B1 patent drawingFigure 3~4
  • EP2002040B1 patent drawingFigure 5

AI summary

A circular knitting machine for hosiery or the like, which comprises at least one needle cylinder (1) which has a vertical axis (1a) and has, on its lateral surface, a plurality of axial slots (2), each of which accommodates a needle (6) and an element (10) for actuating the needle (6). The actuation element (10) comprises at least one connecting element (4) and a selector (5). The connecting element (4) is provided with a movable heel (4a) which can be extracted radially from the axial slot (2) by way of the oscillation of the connecting element (4) on a radial plane of the needle cylinder (1), and the selector (5) protrudes with a portion (14) between the bottom of the axial slot (2) and the connecting element (4) in any position which can be assumed by the connecting element (4) during the operation of the machine. The selector (5) is able to oscillate on command on a radial plane of the needle cylinder (1) in order to produce the oscillation of the connecting element (4) and extract its movable heel (4a) from the axial slot (2) so as to achieve its engagement with connecting element actuation cams which face the lateral surface of the needle cylinder (1).