Grinder Controller Terminal Dust Protection

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Solution Overview

Problem

Existing grinders face challenges in achieving effective dust resistance between the terminals of a switch block and a controller, especially in narrow spaces, leading to potential electrical leaks and increased assembly time and costs.

Innovation Solution

A grinder design featuring a cylindrical housing with a switch block and controller assembly that includes a male terminal and female terminal connection system, where the male terminal is inserted into the female terminal through an entry opening, and a closing portion covers the entry opening, allowing for simple and quick assembly while maintaining dust resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead wiring is used to connect electronic components without plugs and sockets, then electrical leak prevention is improved, but assembly time increases and costs increase

Engineering Contradiction:
Improveelectrical leak preventionVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The terminal connection structure is segmented into a male terminal with an insertion portion and a female terminal with an entry opening, allowing for modular assembly while maintaining electrical safety

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The male terminal acts as an intermediary component between the plug and socket, providing a protected connection path that prevents dust ingress while enabling quick assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a hollow cylindrical member is used to protect terminal connections from dust, then dust resistance is improved, but device complexity increases due to additional components and insertion portions

Engineering Contradiction:
Improvedust resistanceVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective function and connection function are merged into a single integrated terminal structure, where the male terminal's insertion portion and the female terminal's entry opening work together to provide both protection and electrical connection without requiring separate protective housings

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The terminal connection structure serves multiple functions simultaneously: it provides electrical connection, dust protection, and mechanical retention through the engagement of the insertion portion and entry opening, eliminating the need for separate protective components

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If a cylindrical member with insertion portion is used between switch block and controller, then dust resistance is improved, but ease of manufacture decreases due to difficult assembly in narrow spaces

Engineering Contradiction:
Improvedust resistanceVSAvoidassembly difficulty
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Instead of inserting a protective cylindrical member into the terminal connection, the design inverts the approach by making the male terminal itself the protective element through its insertion portion that engages with the female terminal's entry opening, simplifying assembly in narrow spaces

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2384855B1Grinder with improved connection between controller and switch block for better protection against grinding dust
Publication Date: 2017.06.14 MAKITA CORP
  • EP2384855B1 patent drawingFigure 1
  • EP2384855B1 patent drawingFigure 2
  • EP2384855B1 patent drawingFigure 3A~3C

AI summary

In a grinder, a terminal plate (67) is projectingly provided on an upper surface of a controller (60). A connection portion (48), which accommodates a female terminal (49) and includes a slit (50) into which the terminal plate (67) enters, is projectingly provided on a lower surface of a main body portion (39) of a switch block (30). At the time of assembling of the switch block (30) and the controller (60), the terminal plate (67) that enters into the connection portion (48) from the slit (50) is inserted into and connected to the female terminal (49). First and second projections (68), (69) that cover a formation surface of the slit (50) in the connection portion (48) when the connection portion (48) is inserted with and connected to the terminal plate (67) are formed on the upper surface of the controller (60).