Electric Trimmer Double-Structure Housing for Stable Base Fixation

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Solution Overview

Problem

The existing electrically-powered trimmer design faces issues with operability due to potential deformation or damage of the motor case, concentration of force on one portion of the base, and sudden loss of fixing force, leading to reduced stability and usability.

Innovation Solution

A work machine design featuring a housing with a double structure including an inner and outer case, a base with a fixing mechanism that distributes force through multiple points, and a holding mechanism to maintain temporary fixation, enhancing stability and operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cylinder part of the base is deformed to tighten the motor case, then the base is fixed to the motor case, but the motor case may be deformed or damaged by the tightening force

Engineering Contradiction:
Improvefixing force of the baseVSAvoiddeformation or damage of the motor case
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A buffer member is introduced as an intermediary element between the cylinder part and the motor case. This buffer member absorbs and distributes the tightening force, preventing direct transmission of concentrated stress to the motor case while maintaining effective fixation. The buffer member acts as a mediator that resolves the conflict between achieving strong fixation and preventing damage to the motor case.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the lever is provided in one place in the cylinder part of the base, then the structure is simple, but the force from the lever concentrates on one portion causing deformation

Engineering Contradiction:
Improvestructure of the fixing mechanismVSAvoiddeformation of the cylinder part
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The fixing mechanism is segmented into multiple functional elements: the cylinder part, the buffer member, and the lever system are divided into distinct components with specific roles. The buffer member is positioned at a specific location to distribute the lever's force across a broader area of the cylinder part, preventing stress concentration while maintaining structural simplicity. This segmentation allows each component to perform its function optimally without causing deformation.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the lever is operated to release the tightening force, then the base can be detached, but the fixing force disappears immediately causing the base to fall to the motor case

Engineering Contradiction:
Improveoperation of releasing the leverVSAvoidfixing force of the base
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The buffer member provides beforehand cushioning by maintaining residual support even when the lever is released. Instead of allowing the fixing force to disappear immediately, the buffer member continues to provide gentle support, preventing the base from suddenly falling onto the motor case. This prior cushioning ensures smooth and safe detachment while maintaining ease of operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4238729B1Work machine
Publication Date: 2025.07.16 KOKI HLDG CO LTD
  • EP4238729B1 patent drawingFigure 1
  • EP4238729B1 patent drawingFigure 2
  • EP4238729B1 patent drawingFigure 3

AI summary

The present invention realizes a work machine having improved operability. In an electric-powered trimmer 10, a housing 22 that forms the contour of a trimmer body 20 includes an inner case 24 having a cylindrical inner cylinder part 26 and an outer case 30 externally inserted onto the inner case 24, and the outer case 30 is fixed to the inner case 24. In other words, the housing 22 forms a double structure of the inner case 24 and the outer case 30. Therefore, the rigidity of the housing 22 can be increased. Moreover, the outer case 30 is formed from a single member that cannot be disassembled; and a base cylinder part 62 of a base 60 is detachably and externally inserted onto the outer case 30. In other words, a portion directly supporting the base cylinder part 62 is formed from a single member that cannot be disassembled. Accordingly, the support rigidity of the housing 22 with respect to the base cylinder part 62 can be increased.