Insulated Screws for Hand-Held Power Tools
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Solution Overview
Problem
Hand-held power tools with metal gear housings pose a risk of electric shock to users due to potential current conduction through screws, especially when damaged, as existing technologies lack effective electrical insulation between metal components and screws.
Innovation Solution
An electrical insulating unit is introduced, comprising an electrolytically applied non-conductive surface coating on screws and additional insulating elements like shrink tubing and insulating ribs, ensuring minimal conductivity and protecting users from electric shock by preventing current flow between metal components and screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screws are used to fasten metal components without additional insulation, then device complexity is reduced and manufacturing cost is lowered, but electrical insulation between metal components and screws cannot be ensured, creating electric shock risk
Solution Approach 1:
The patent applies preliminary action by pre-coating the screws with an electrolytically applied non-conductive material before assembly. This insulation layer is applied in advance during screw manufacturing, so that when the screw is assembled into the metal component, the insulation is already in place, preventing current conduction without requiring additional insulation steps during device assembly
Solution Approach 2:
The patent uses an electrolytically applied non-conductive coating as an intermediary substance between the metal screw and the metal component. This coating layer acts as a mediator that physically separates the conductive metal surfaces, preventing direct electrical contact while still allowing the screw to perform its fastening function
2Ease of manufacture
If screws are used without insulation coating, then manufacturing process is simpler and cost is lower, but electrical conductivity between metal parts occurs, posing safety risk
Solution Approach 1:
The patent applies self-service by having the screw itself provide the insulation function through its own coating. The electrolytically applied non-conductive coating is applied directly to the screw surface, making the screw self-insulating without requiring separate insulation components or additional assembly steps, thus maintaining manufacturing simplicity while ensuring safety
Solution Approach 2:
The patent changes the electrical conductivity parameter of the screw by applying an electrolytic coating that transforms the surface properties. The coating process modifies the screw's electrical characteristics from conductive to non-conductive, while the screw's mechanical fastening properties remain unchanged, allowing it to perform both functions simultaneously
3Object-affected harmful factors
If additional insulating elements are added to ensure electrical insulation, then user safety is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the fastening function and the insulation function into a single component - the screw. By applying the electrolytic coating directly to the screw, the screw simultaneously performs both mechanical fastening and electrical insulation, eliminating the need for separate insulation elements and reducing overall device complexity
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
The solution effectively prevents electric shock by maintaining low conductivity between metal components and screws, allowing for safe handling of hand-held power tools without structural redesign and reducing costs through the use of commercially available screws with coatings.
Implementation Method 1
the surface coating consists of an electrolytically applied, non-conductive material
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a machine tool device, particularly a hand-held machine tool device, comprising at least one screw (30) that is provided to secure at least one metal component to at least one additional component, in a form-fitting manner. According to the invention, an electrical insulating unit (40) is provided to prevent the conduction of current at least between the metal component and the screw (30).