Portable Work Tool Soft Layer Restraining Surface Design

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Solution Overview

Problem

The bonding strength of the soft layer on the outer surface of portable work tools, such as impact drivers, degrades over time, causing it to come off, which compromises the tool's operability and shock resistance.

Innovation Solution

A portable work tool design featuring a housing with a covered region and an uncovered region, where the soft layer is restrained by projections or grooves that protrude from the covered region, preventing edge portions from detaching and ensuring a secure bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the soft layer is bonded to the outer surface of the housing after molding, then the housing provides good fitting feeling and shock protection, but the bonding strength degrades over time causing the soft layer to come off

Engineering Contradiction:
Improveshock protectionVSAvoidbonding strength
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The housing is designed with protrusions formed during the molding process itself, before the soft layer is applied. These protrusions create mechanical interlocking features that prevent the soft layer from detaching during subsequent use, addressing the bonding strength degradation issue before it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention combines the hard housing material with a soft layer to create a composite structure. The protrusions integrate these two materials mechanically, allowing the hard housing to provide structural support while the soft layer provides shock absorption and comfortable grip, maintaining both properties over time.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the soft layer is bonded to the outer surface of the housing, then the housing provides comfortable grip and operability, but the soft layer detaches during continued use

Engineering Contradiction:
Improvegrip comfortVSAvoidlayer integrity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The protrusions are pre-formed on the housing surface during molding, creating a mechanical anchoring system before the soft layer is applied. This preliminary structural feature ensures that the soft layer remains securely attached while providing comfortable grip characteristics throughout the tool's service life.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The protrusions are strategically positioned at specific locations on the housing where the soft layer is applied. This localized structural feature provides enhanced anchoring exactly where needed to maintain layer integrity, while allowing the soft layer to provide uniform grip comfort across the entire contact surface.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2945782B1Portable work tool
Publication Date: 2019.03.13 KOKI HLDG CO LTD
  • EP2945782B1 patent drawingFigure 1
  • EP2945782B1 patent drawingFigure 2
  • EP2945782B1 patent drawingFigure 3

AI summary

A portable work tool (1) includes: a housing (2); and a motor (4). The housing (2) has an outer surface including a covered region (11) that is covered with a soft layer (12) and an uncovered region (21) that is exposed to an outside. The covered region and the uncovered region define a boundary (22) therebetween. The motor (4) is accommodated in the housing. The portable work tool is characterized by: a restraining surface (50, 61, 81) disposed in proximity to the boundary and protruding from the covered region.