Concentric Connector Structure for Vibration-Stable Power Tool Contacts

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Solution Overview

Problem

Existing connector devices for electric machine tools suffer from vibration-induced contact failures, short circuits, and poor maintainability due to complex structures that are prone to deformation and rotation, leading to increased maintenance time and effort.

Innovation Solution

A connector device with concentrically arranged male and female contact pieces, featuring convex and concave stepped structures that ensure stable contact and prevent rotation, combined with elastic members and rotation prevention mechanisms to maintain connection integrity during vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cord cap is made of elastic material to prevent vibration, then vibration resistance is improved, but the cord cap may be elastically deformed inward causing connection portions to contact and short circuit

Engineering Contradiction:

Improvevibration resistanceVSAvoidshort circuit risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The connector is divided into separate male and female connectors with distinct contact piece retention portions. The male connector has a retention portion with convex portions, while the female connector has a retention portion with concave portions, separating the contact pieces into independent groups that are less likely to short circuit

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The male and female connectors are designed with asymmetric complementary shapes - the male connector has convex portions that fit into concave portions of the female connector. This asymmetric design ensures proper alignment and prevents the elastic cord cap from deforming inward and causing short circuits

Inventive Principle:

Principle #4Asymmetry

2Reliability

If the hose joint is screwed to the motor housing to secure the connector, then connection stability is improved, but the cord cap may rotate with the hose joint causing connection portion damage

Engineering Contradiction:

Improveconnection stabilityVSAvoidrotational damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The male and female connectors have asymmetric complementary shapes with convex and concave portions that fit together. This asymmetric design provides inherent anti-rotation capability, preventing the cord cap from rotating when the hose joint is screwed to the motor housing

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The contact pieces are pre-positioned in their retention portions with convex and concave shapes that engage before the hose joint is fully screwed. This preliminary engagement prevents rotational movement during the screwing process, protecting the connection portions from damage

Inventive Principle:

Principle #10Preliminary action

3Reliability

If minimum wiring connections are used to achieve vibration resistance, then vibration resistance is improved, but maintainability deteriorates when defects occur

Engineering Contradiction:

Improvevibration resistanceVSAvoidmaintainability

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The connector is designed as a separable device with male and female connectors that can be easily disconnected. The contact pieces are retained in separate retention portions, allowing the connector to be divided into manageable sections for maintenance and repair

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connector device serves multiple functions: it provides vibration resistance through its secure fit, enables easy maintenance through separable design, and ensures electrical connection through the contact pieces. This multi-functional design improves maintainability without compromising vibration resistance

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides enhanced vibration resistance, prevents contact failures and short circuits, and facilitates easy assembly and disassembly, improving maintainability and connection stability.

Implementation Method 1

the cord cap made of an elastic material is elastically deformed in a circumferential direction due to a pressing force applied in a connection axis direction, and thus the cord cap is brought into tight contact with the inner peripheral surface of the hose joint

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12555945B2Connector device for an electric machine tool

Publication Date: 2026.02.17 EXEN ENVIRONMENTAL

AI summary

A connector device according to one or more embodiments includes a male connector including multiple male contact pieces, and a male contact piece retention portion, and a female connector including multiple female contact pieces, and a female contact piece retention portion. The male contact piece retention portion has multiple concentrically formed convex portions. The multiple male contact pieces are mounted on an outer circumferential wall of the convex portions, and arranged concentrically, with a tip end thereof being inclined toward the center of the convex portions. The female contact piece retention portion has concentrically formed multiple concave portions. The multiple female contact pieces are mounted on an inner circumferential wall of the concave portions, and arranged concentrically, with a base end thereof being inclined toward the center of the concave portions. The convex portion and the concave portion are brought into contact and tightly fitted with one another.