Thread Finger With Nested Guide Element For Compact Knitting Machines

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Solution Overview

Problem

Existing thread fingers for knitting machines require a large installation space due to their wide design, limiting the number of knitting threads that can be processed and increasing knitting time, making it economically unjustifiable to broaden the thread changing device.

Innovation Solution

A thread finger design where the guide element is guided within the finger body, allowing for a significantly smaller overall width, with the cutting knife and clamping element arranged on opposite sides or the same side of the finger body, and a spring mechanism for clamping, enabling simultaneous cutting and clamping actions without protruding beyond the finger body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hollow, box-shaped guide body encloses the finger body, then the cutting knife and clamping element can be displaceable together with the guide body, but the thread finger requires a large installation space

Engineering Contradiction:
Improvedisplaceable cutting knife and clamping elementVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The guide element is inserted into the finger body and guided within it, with the guide element having a smaller cross-section than the finger body. This nesting arrangement allows the cutting knife and clamping element to be displaced together with the guide element while maintaining a compact overall width, resolving the contradiction between reliable displacement and large installation space requirement

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If several wide thread fingers are arranged parallel to process multiple knitting threads, then more knitting threads can be processed, but the thread changing device requires a larger overall width

Engineering Contradiction:
Improvenumber of knitting threads processedVSAvoidoverall width
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

By nesting the guide element within the finger body, the overall width of each thread finger is significantly reduced. This allows more thread fingers to be arranged parallel within the same overall width, thereby increasing the number of knitting threads that can be processed without expanding the device width

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The guide element is designed with a flat profile where its thickness can continuously correspond to the width of the longitudinal slot, allowing optimization in the lateral dimension. This dimensional optimization enables closer spacing of parallel thread fingers, increasing productivity without increasing overall device width

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

3Area of stationary object

If the guide element is designed as a flat profile part with thickness corresponding to the longitudinal slot width, then the thread finger width can be minimized

Engineering Contradiction:
Improvethread finger widthVSAvoidguide element design
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The guide element's thickness parameter is designed to continuously correspond to the width of the longitudinal slot, allowing the slot to be as narrow as possible. This parameter optimization minimizes the overall thread finger width while maintaining the functional integrity of the guide element, resolving the contradiction between compact size and design complexity

Inventive Principle:
Principle #35Parameter changes

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

This design allows for a higher number of knitting threads to be processed without reducing output, as more thread fingers can be accommodated in the same space, enhancing the efficiency and cost-effectiveness of the thread changing device.

Implementation Method 1

The guide element can press the clamping element against the finger body by means of a spring.

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The spring can be a separate element or a resilient section of the clamping element itself.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2385161B1Thread finger for a thread changing device
Publication Date: 2017.12.20 SIPRA PATENTENTWICKLUNGS UND BETEILIGUNGSGESELLSCHAFT MBH
  • EP2385161B1 patent drawingFigure 1~2b
  • EP2385161B1 patent drawingFigure 3~7c

AI summary

The thread finger (10) has an elongated finger body (11) with an end fastened at a pivotal lever (14), where other end of the finger body includes a thread receiving area (12) for a knitting thread. A guide element (19) is movable along the finger body. A cutting knife (22) and a clamping element (24) are movable together with the guide element, where the clamping element is prestressed by spring force. The finger body is formed with a longitudinal slot (18). The guide element is displaceably supported in the longitudinal slot, where the finger body is formed as a metallic sheet punched part.