Fishing Line Guide Frame Geometry for Snag Release

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Solution Overview

Problem

Conventional fishing line guides often struggle to release a line snagged in a loop due to the protrusion of the connecting portion between the fixing portion and the ring retainer, which causes high resistance and makes it difficult to release the line, especially in boat fishing where the line gets snagged on the curved surface at the inflection point between the connecting and guide ring retainers.

Innovation Solution

The fishing line guide is designed with a frame where the width of the inflection point between the connecting portion and the ring retainer is equal to or greater than 70% of the maximum width of the ring retainer, allowing the snagged line to move towards the ring retainer and away from the frame, and the connecting portion is bent and raised at a predetermined angle to facilitate line release, using a fiber-reinforced prepreg material for the frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the connecting portion between the fixing portion and ring retainer significantly protrudes in the widthwise direction, then the structural integrity and stability of the line guide is improved, but the line becomes difficult to release when snagged in a loop

Engineering Contradiction:
Improvestructural integrityVSAvoidline releaseability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a specific geometric configuration at the critical connecting portion between the fixing portion and ring retainer. The connecting portion is designed with a width that is 70% or more of the ring retainer's maximum width, and the inflection point is positioned to create a smooth transition surface. This localized geometric optimization allows the line to slide off easily from the inflection point while the overall protruding structure maintains structural integrity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the connecting portion is formed with a short curved surface for manufacturing reasons, then the manufacturing complexity is reduced, but the line tends to be snagged on the curved surface and stopped at the inflection point

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidline releaseability
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies parameter changes by optimizing the width parameter of the connecting portion and the position parameter of the inflection point. Specifically, the connecting portion width is set to 70% or more of the ring retainer's maximum width, and the inflection point is positioned at a specific location along the curved surface. These parameter optimizations enable the line to be released easily while maintaining manufacturing simplicity through the use of a short curved surface.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the line guide frame has a forwardly-slanted structure (60 to 45°), then the line releaseability is improved, but the connecting portion still causes persistent snagging when the line forms a loop

Engineering Contradiction:
Improveline releaseabilityVSAvoidline snagging at inflection point
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by designing the connecting portion with a specific width (70% or more of the ring retainer's maximum width) and positioning the inflection point to create a smooth transition surface before the line reaches the problematic area. This preliminary geometric configuration guides the line to slide off easily from the inflection point, preventing the line from getting snagged and stopped, thus eliminating the harmful snagging effect even when the line forms a loop.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2845479B1Fishing line guide and fishing rod
Publication Date: 2019.07.24 DAIWA SEIKO CORPORATION
  • EP2845479B1 patent drawingFigure 1
  • EP2845479B1 patent drawingFigure 2a~2b
  • EP2845479B1 patent drawingFigure 3a~3b

AI summary

One object is to provide a fishing line guide that allows a line snagged in a loop to be released readily. The line guide 5 according to the present invention include a frame including a fixing portion fixed on the outer surface of the rod, a ring retainer retaining a guide ring that admits the line, and a connecting portion connecting the ring retainer and the fixing portion. For a width Wa of the frame at the inflection point between the connecting portion and the ring retainer and a maximum width Wb of the ring retainer, the frame 5A is formed such that the width Wa is equal to or greater than 70% of the maximum width Wb.