Knitting Machine Lay-Bar Drive Tilt Control

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Solution Overview

Problem

The existing laying bar drives in warp knitting machines face accuracy issues due to torque-induced tilting of the output area, which affects the quality of warp knitted fabric production, especially at higher finenesses, as the output area is laterally offset from the drive axis, leading to undesirable movement and reduced precision.

Innovation Solution

The implementation of at least two transmission members that support each other to counteract the torque, with multiple bearings and a displacement unit extending parallel to the drive axis, along with a spring tensioner and a console arrangement, to maintain the output area's position and prevent tilting, thereby enhancing the stiffness and accuracy of the drive without increasing its mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the output section is arranged laterally offset from the drive axis to enable guide bar movement, then the guide bar can be moved in the offset direction, but a torque acts on the transmission link causing the output section to tilt and change position, reducing control accuracy

Engineering Contradiction:
Improveguide bar movement capabilityVSAvoidoutput section position accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces a new spatial dimension by arranging multiple transmission links in a multi-dimensional configuration rather than a single linear arrangement. The transmission links are positioned at different locations and orientations, creating a three-dimensional support structure that counteracts torque through geometric distribution of forces, thereby maintaining output section accuracy while preserving guide bar movement capability

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

Solution Approach 2:

Multiple transmission links are merged into a coordinated system where each link contributes to both driving the guide bar and counteracting torque. The transmission links work together as an integrated mechanism, with their combined structural arrangement providing both the necessary movement function and the anti-torque stability, resolving the contradiction between movement capability and position accuracy

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If the mass of the transmission link is increased to reduce deflection and improve stiffness, then the drive becomes stiffer and more accurate, but the energy requirements increase and the system becomes heavier

Engineering Contradiction:
Improvedrive stiffnessVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The transmission system is segmented into multiple separate transmission links rather than using a single massive component. Each transmission link is individually sized to be lightweight, but collectively they provide the necessary stiffness through their distributed arrangement. This segmentation allows the system to achieve high stiffness without requiring any single component to be overly massive, thereby reducing overall energy consumption

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a composite structural arrangement where multiple transmission links with different orientations and positions work together to create an equivalent stiff structure. This composite configuration achieves the mechanical stiffness of a heavy single-component system while using lighter individual elements, reducing the total mass and associated energy requirements for acceleration and operation

Inventive Principle:
Principle #40Composite materials

3Reliability

If multiple transmission members are arranged to support each other against torque, then the output section position stability is improved, but the device complexity increases

Engineering Contradiction:
Improveoutput section position stabilityVSAvoidtransmission system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each transmission link is designed to perform multiple functions simultaneously: transmitting drive forces to move the guide bar, providing structural support to counteract torque, and maintaining positional accuracy of the output section. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity while achieving high reliability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The transmission links are arranged in a configuration where they experience equivalent mechanical conditions and share the load uniformly. This equipotential arrangement ensures that each link contributes equally to torque counteraction, simplifying the design and analysis compared to asymmetric configurations, and thereby limiting complexity increase while maximizing position stability

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP4151790B1Guide bar drive for a knitting machine
Publication Date: 2024.08.21 KARL MAYER STOLL R&D GMBH
  • EP4151790B1 patent drawingFigure 1~2

AI summary

A lay-bar drive for a warp knitting machine is described, comprising a driven transmission element (1) with an output section (7) and a body (3) mounted in a body bearing (4, 5). The transmission element (1) is driven by drive forces acting along a drive axis (6), and the output section (7) is arranged laterally offset from the drive axis (6). The aim is to increase the natural frequency of the lay-bar drive train. For this purpose, the output section (7) is provided with at least one bearing (16, 17) separate from the body bearing (4, 5), which acts as a tilt protection device.