Trimmer Head Line Release Knob Axial Movement

Solution Overview

Problem

Existing handheld trimmer devices face difficulties in loading trimmer line due to the design of the line release knob, which either complicates the process or limits the device's ability to cut at low heights and maintain stability.

Innovation Solution

A line holding assembly with a spool and core that allows axial movement of the line release knob for easy loading while preventing axial movement of the spool, enabling quick and easy replenishment of trimmer line without disassembling the trimmer head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the line release knob is extended outwardly from the trimmer head, then it facilitates easy grasping and turning for loading trimmer line, but it limits the ability to cut at low heights and may cause unintended bouncing of the trimmer head

Engineering Contradiction:

Improveease of loading trimmer lineVSAvoidability to cut at low heights

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The line release knob is designed to be movable relative to the trimmer head, allowing it to extend outwardly when not in use for easy grasping and turning, and retract inwardly when cutting at low heights to prevent bouncing and maintain versatility. This dynamic adjustment resolves the contradiction between ease of operation and adaptability to different cutting conditions.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the line release knob is extended outwardly from the trimmer head, then it facilitates easy grasping and turning for loading trimmer line, but it contacts the ground during operation causing instability

Engineering Contradiction:

Improveease of loading trimmer lineVSAvoidstability of trimmer head during operation

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The line release knob is designed to be movable relative to the trimmer head, allowing it to extend outwardly when not in use for easy grasping and turning, and retract inwardly when cutting at low heights to prevent bouncing and maintain versatility. This dynamic adjustment resolves the contradiction between ease of operation and adaptability to different cutting conditions.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the spool is allowed to move axially, then it facilitates easy loading of trimmer line, but it causes instability and unintended bouncing of the trimmer head

Engineering Contradiction:

Improveease of loading trimmer lineVSAvoidstability of trimmer head during operation

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The trimmer head is divided into separate functional components: a spool that is fixed axially to prevent bouncing and maintain stability, and a core with a movable line release knob that facilitates easy loading of trimmer line. This segmentation allows each component to perform its specific function independently, resolving the contradiction between ease of loading and operational stability.

Inventive Principle:

Principle #1Segmentation

4Stability of the object's composition

If the knob is fixed axially, then it prevents bouncing during operation, but it makes loading trimmer line difficult

Engineering Contradiction:

Improvestability of trimmer head during operationVSAvoidease of loading trimmer line

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The trimmer head is divided into separate functional components: a spool that is fixed axially to prevent bouncing and maintain stability, and a core with a movable line release knob that facilitates easy loading of trimmer line. This segmentation allows each component to perform its specific function independently, resolving the contradiction between ease of loading and operational stability.

Inventive Principle:

Principle #1Segmentation

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

Facilitates quick and easy loading of trimmer line while maintaining the ability to cut at low heights and preventing unintended bouncing of the trimmer head, enhancing user experience and operational efficiency.

Implementation Method 1

The trimmer line, which may be a monofilament line, is quite effective at cutting when rotated at high speed. Such a trimmer line is extended and held somewhat rigid by centrifugal forces while being rotated.

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS10874046B2Quick loading trimmer head and trimmer thereto

Publication Date: 2020.12.29 HUSQVARNA AB

AI summary

A hand-held cutting device (10) including an elongated member (45), a trimmer head (25), and a power unit operably coupled to the trimmer head (25) to selectively cause rotation of the trimmer head (25). The trimmer head (25) includes a line holding assembly (110, 310) to hold and selectively release trimmer line (70), and a housing to house the line holding assembly (110, 310), wherein the line holding assembly (110, 310) includes a core (140, 340), a line-release knob (160, 350), and a spool (130) configured to hold the trimmer line (70). The knob (160, 350) is axially movable with respect to the core (140, 340) between an extended first position and a retracted second position, the knob (160, 350) extending outwardly from the housing and being non-rotatably fixed to the core (140, 340) when the knob (160, 350) is in the first position.