Vehicle Earthing Terminal Clamp to Prevent Cross-Threading

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Solution Overview

Problem

Existing earthing point systems in motorized vehicles are prone to cross-threading during assembly, leading to potential failure of the earthing connection, which can result in catastrophic electrical system malfunctions.

Innovation Solution

A device with a collapsible core and cone mechanism that securely clamps an earthing terminal using a spindle and cone system, featuring a threaded engagement and a retaining means to prevent disengagement, ensuring reliable attachment and reducing the likelihood of cross-threading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional fixing bolt with nut and threaded section is used to attach an earthing terminal, then the assembly process is simple, but cross-threading may occur leading to potential failure of the earthing connection

Engineering Contradiction:
Improvereliability of earthing connectionVSAvoidease of assembly
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a cone as an intermediary component between the spindle and the earthing terminal. The cone includes a through hole with a thread that engages with the threaded section of the spindle, and the collapsible core with clamping segments that interface with the earthing terminal. This intermediary cone mechanism prevents direct threaded engagement between the bolt and terminal, eliminating cross-threading risks while maintaining assembly simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The collapsible core is configured to automatically expand and clamp the earthing terminal when the cone is rotated onto the spindle. The deformation of the collapsible core is self-actuating through the mechanical engagement of the threaded sections, requiring no additional fastening operations. This self-service mechanism ensures reliable clamping without complicating the assembly process.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If a fixing bolt with nut is used to secure an earthing terminal, then the attachment method is conventional and simple, but the electrical contact surface may be compromised during assembly or painting processes

Engineering Contradiction:
Improveelectrical contact surface qualityVSAvoidease of assembly and painting processes
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The earthing terminal is clamped to the mounting section by the collapsible core before the painting process is performed. This preliminary clamping action protects the electrical contact surface from paint contamination and ensures proper positioning before subsequent manufacturing steps. The cone and collapsible core mechanism is designed to maintain this clamped state throughout the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a conventional nut and bolt system is used, then the components are simple and easy to manufacture, but the system lacks a retaining means to prevent disengagement of threaded sections

Engineering Contradiction:
Improveprevention of disengagementVSAvoidcomplexity of cone and collapsible core mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cone is rotatably received within the mounting section, and the collapsible core is nested within the cone. The clamping segments of the collapsible core are positioned to clamp the earthing terminal when the cone is in its rotated position. This nested arrangement provides a retaining mechanism that prevents disengagement while integrating multiple functions into a compact structure. The conventional spindle and threaded sections remain simple, but the nested cone and collapsible core add the necessary retention capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 device provides a reliable and efficient earthing point by minimizing cross-threading risks, ensuring consistent electrical connectivity and facilitating easy assembly and painting processes without compromising the electrical contact interface.

Implementation Method 1

The cone includes a through hole which includes a thread and the through hole and the thread are configured mutually to engage with the threaded section of the spindle so that rotation of the cone about the rotation axis causes the cone to travel towards or away from the mounting section by a screwing action caused by engagement of the thread of the through hole with the threaded section of the spindle

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

The deformable section is configured to transition to an expanded state by pressure of the cone engaging with the collapsible core caused by the screwing action as the cone is rotated about the rotation axis causing the cone to travel along the spindle towards the mounting section by the mutual engagement of the threaded section of the spindle and the thread of the through hole

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

The cone, the collapsible core and the spindle are configured to clamp an earthing terminal on the mounting section when the deformable section of the collapsible core is in the expanded state caused by the action of the cone being screwed on the spindle towards the mounting section and the clamping end of the deformable section in the expanded state forcing the earthing terminal against the mounting section from pressure from the screwing action

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4071000B1Device for earthing and methods
Publication Date: 2025.11.05 JST MFG CO LTD
  • EP4071000B1 patent drawingFigure 1
  • EP4071000B1 patent drawingFigure 2
  • EP4071000B1 patent drawingFigure 3

AI summary

A device for providing an earthing point of a motorised vehicle is provided. The device includes a mounting section configured to attach the device to the motorised vehicle and to provide, when attached to the motorised vehicle, an electrical earth for one or more electrical components of the motorised vehicle by connection to an earthing terminal. The device comprises a spindle extending from the mounting section along an axial length defining a rotation axis. The spindle includes a threaded section along at least part of the axial length. The device comprises a collapsible core and a cone configured to engage with the collapsible core. The cone includes a through hole which includes a thread and the through hole and the thread are configured mutually to engage with the threaded section of the spindle so that rotation of the cone about the rotation axis causes the cone to travel towards or away from the mounting section by a screwing action caused by engagement of the thread of the through hole with the threaded section of the spindle. The collapsible core includes a through section which allows the collapsible core to be mounted on the spindle and a deformable section which is biased in a collapsed state in which a clamping end of the collapsible core proximate the mounting section is in a retracted position. The deformable section is configured to transition to an expanded state by pressure of the cone engaging with the collapsible core caused by the screwing action as the cone is rotated about the rotation axis causing the cone to travel along the spindle towards the mounting section by the mutual engagement of the threaded section of the spindle and the thread of the through hole. The cone, the collapsible core and the spindle are configured to clamp an earthing terminal on the mounting section when the deformable section of the collapsible core is in the expanded state caused by the action of the cone being screwed on the spindle towards the mounting section and the clamping end of the deformable section in the expanded state forcing the earthing terminal against the mounting section from pressure from the screwing action. The spindle and the cone include a retaining means preventing the thread of the through hole of the cone disengaging with the threaded section of the spindle.