Thread Trimmer Vibration Damping Structure

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Solution Overview

Problem

Existing line trimmers often experience internal thread breaks due to vibration-induced friction welding, leading to laborious thread rethreading and reduced operational efficiency.

Innovation Solution

Incorporation of vibration-damping means between the thread passage opening and spool winding, featuring a deflection structure with a continuously curved surface and additional friction surfaces, which reduces oscillations and frictional forces, guiding the thread on a deflection surface with a smaller radius of curvature and offset angle to minimize friction welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the thread is guided directly from the spool winding to the line passage opening, then the thread path is simple and direct, but vibrations cause friction welding between thread windings leading to internal thread breaks

Engineering Contradiction:
Improvethread path simplicityVSAvoidthread integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A vibration-damping means is introduced as an intermediary element between the spool winding and the line passage opening. This mediator component absorbs and dampens vibrations in the thread, preventing the transmission of vibrational energy that causes friction welding and internal thread breaks, while still allowing the thread to be guided from the spool to the opening.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The vibration-damping means converts the harmful vibrational energy into beneficial frictional damping. By introducing controlled friction through the damping means, the harmful vibrations are dissipated as heat through friction, preventing the unwanted friction welding between thread windings while maintaining thread integrity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If vibration-damping means are added to reduce vibrations, then thread breakage is reduced, but the device complexity increases

Engineering Contradiction:
Improvethread integrityVSAvoidspool holder structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The vibration-damping means is applied locally at the specific location where vibrations cause problems - between the spool winding and the line passage opening. Rather than redesigning the entire spool holder structure, the damping function is concentrated in a localized component that can be easily integrated into the existing design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The vibration-damping means is implemented as a simple, inexpensive component that can be easily replaced if needed. The design uses basic friction-based damping elements rather than complex mechanical systems, making the component cost-effective and simple to manufacture and install.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Significantly reduces the occurrence of thread breaks by nearly 50% by dampening vibrations and frictional forces, ensuring the thread remains intact and functional during operation.

Implementation Method 1

vibration-damping means between the line opening and the line winding on the spool an additional friction surface is arranged as a deflection surface, which dampen the propagation of vibrations along the cutting line

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

when the spool holder is driven in rotation, is tensioned radially taut by the centrifugal force and cuts the plant material

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2334163B1Thread trimmer
Publication Date: 2017.09.20 HUSQVARNA AB
  • EP2334163B1 patent drawingFigure 1~2
  • EP2334163B1 patent drawingFigure 3~4(B)

AI summary

The invention relates to a thread trimmer to guide the thread guide of the cutting thread from the bobbin winder to a threading opening in a bobbin holder not directly tangential from the threading opening to the bobbin winder, but to guide the thread guide via a deflection structure which has a vibration attenuating effect, thus significantly reducing the transmission of vibrations on the thread section tangentially abutting the bobbin winder induced at the loose end of the cutting thread, and therefore avoiding or greatly reducing any welded joints of the cutting thread between multiple bobbin windings on the bobbin winder.