Fishing Reel Spool Rotation Sensing for Accurate Line Length

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Solution Overview

Problem

Conventional methods for calculating the length of a reeled-out fishing line require time-consuming and effort-intensive input of the line length and number of revolutions, making it difficult to handle pre-winding and high breakage scenarios effectively.

Innovation Solution

A line length measuring device that calculates line length using a rotation detector to detect spool revolutions, a line length calculator, and a fishing line information setting part that allows input of the line type and winding diameter, eliminating the need for line length input and revolution measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If actual measurement method is used to calculate constants A and B, then measurement precision is improved, but loss of time increases

Engineering Contradiction:

Improveline length measurement precisionVSAvoidtime for actual measurement

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores constant values A and B for different fishing line specifications (diameter, material, spool dimensions) before actual use. Users can directly select from pre-stored constant sets corresponding to their fishing line type, eliminating the need for time-consuming actual measurement while maintaining measurement precision through the use of accurately pre-calculated constants.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the approach from measuring physical parameters during use to storing pre-calculated parameter sets. By varying the fishing line specification parameters (diameter, material) and pre-calculating corresponding constant sets, the system enables quick selection without actual measurement, resolving the contradiction between precision and time consumption.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If conventional line length measurement method is used, then device complexity is reduced, but ease of operation deteriorates

Engineering Contradiction:

Improveease of line length settingVSAvoidcomplexity of information input

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent enables the system to automatically determine line length by detecting spool rotation and using pre-stored constant sets. The device performs calculations automatically based on selected fishing line specifications, eliminating the need for users to manually input complex information, thus improving ease of operation without significantly increasing device complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent creates a universal system that handles various fishing line types and scenarios (pre-winding, high breakage, different diameters) through a single unified approach. By storing multiple constant sets and automatically selecting the appropriate one based on fishing line specifications, the system simplifies user operation while managing diverse scenarios without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of time

If preset values are used for constants A and B, then loss of time is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improvetime for constant selectionVSAvoidline length measurement precision

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent organizes preset constant sets according to specific fishing line parameters (diameter, material, spool dimensions). By changing and categorizing the preset values based on these parameters, users can select the most appropriate constant set for their specific fishing line type, maintaining measurement precision while reducing time loss through organized quick selection.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12514241B2Line length measuring device and fishing reel comprising the same

Publication Date: 2026.01.06 DAIWA SEIKO CORPORATION

AI summary

A line length measuring device that is capable of measuring a line length of a fishing line reeled out from a spool of a fishing reel and includes: a rotation detector capable of detecting a number of revolutions of the spool relative to a reel main body; a line length calculator that calculates a line length of the reeled out fishing line from the number of revolutions detected by the rotation detector; and a fishing line information setting part that sets fishing line information for the calculation of the line length of the reeled out fishing line by the line length calculator, the fishing line information setting part being configured to enable input of a type of a fishing line to be wound and a line winding diameter (Dmax) of the spool after winding of the fishing line to be wound.