Insulated Hand Tool Grip Structure Against Moisture Leakage

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Solution Overview

Problem

Existing hand tools with plastic-coated gripping portions are prone to moisture seepage through holes, leading to electric shock due to conductive pathways formed by moisture between insulation layers, despite having insulated materials.

Innovation Solution

A hand tool design featuring a basic insulation layer with annular protrusions and a skidproof insulation layer with matching annular grooves that prevent moisture seepage and electrical leakage by positioning the protrusions and grooves closer to the joint edges than the holes, thereby isolating the metal tool body from user contact points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plastic layer is coated on the gripping portion by injection molding, then the gripping portion is insulated, but holes are formed in the plastic layer during the molding process

Engineering Contradiction:

Improveinsulation reliabilityVSAvoidintegrity of insulation layer

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

A skidproof insulation layer is wrapped around the plastic layer to cover the holes and provide continuous insulation protection. This flexible film approach allows the insulation to conform to the molded structure while sealing the penetrating holes.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The hand tool employs a composite insulation structure consisting of a plastic layer (basic insulation layer) and a skidproof insulation layer. This multi-material approach combines the advantages of injection-molded plastic with the hole-covering capability of wrapped insulation material.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a skidproof insulation layer is wrapped on the plastic layer to cover the holes, then the holes are covered, but moisture can still seep between the layers from the joint edge

Engineering Contradiction:

Improvehole coverageVSAvoidmoisture ingress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An adhesive layer is introduced as an intermediary between the plastic layer and the skidproof insulation layer. This adhesive not only bonds the two insulation layers together but also creates a moisture barrier that prevents water from penetrating along the interface between layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulation system is enhanced by adding a third material (adhesive) to create a three-layer composite structure. This composite approach addresses the moisture ingress issue by combining the hole-covering function with a bonding and sealing function.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the plastic layer and skidproof insulation layer are made of insulated materials, then the materials are non-conductive, but electricity can still leak through moisture to the user

Engineering Contradiction:

Improvematerial insulation propertyVSAvoidelectrical leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The electrical insulation system uses a composite structure of plastic layer, adhesive layer, and skidproof insulation layer. This multi-layer composite provides redundant insulation paths, ensuring that even if one layer is compromised, the others maintain electrical isolation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The adhesive layer serves as an intermediary insulation barrier between the plastic and skidproof layers. It prevents moisture from creating a conductive path between the two insulated surfaces, thereby blocking electrical leakage to the user.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If the gripping portion is clamped during the forming process, then the plastic layer is formed, but holes are created in the process

Engineering Contradiction:

Improvemolding process feasibilityVSAvoidsurface integrity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The harmful effect (holes) is extracted and addressed by adding a separate component (skidproof insulation layer) that specifically covers the holes created during molding. This allows the molding process to remain simple while the post-processing step remedies the surface defect.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The final insulation structure is a composite of the molded plastic layer and the wrapped skidproof insulation layer. This composite approach accepts the holes as an inevitable byproduct of molding while providing a separate layer to cover them, maintaining both manufacturing ease and surface integrity.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12466053B2Hand tool with function of preventing electric shock

Publication Date: 2025.11.11 INFAR IND CO LTD

AI summary

A hand tool with a function of preventing electronic shock includes a tool body, a basic insulation layer and a skidproof insulation layer. The basic insulation layer is formed on the tool body and has holes exposing a part of the tool body. The skidproof insulation layer is formed on the basic insulation layer to cover the holes. Annular protrusions are formed on the outer surface of the basic insulation layer or the inner surface of the skidproof insulation layer and are closer to edges of the basic insulation layer and the skidproof insulation layer than the holes. Therefore, it is possible to prevent electric shock caused by the seeping of moisture or liquid between the basic insulation layer and the skidproof insulation layer.