Spring-loaded locking bolt coupling for power cables

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing power cable couplings with bayonet locks experience self-loosening due to rigid construction, leading to increased electrical contact resistance and instability in welding processes, especially under mechanical vibrations and thermal expansion, which can damage components and affect welding quality.

Innovation Solution

Incorporating a spring-loaded locking bolt that can move axially within the coupling bolt, providing a pretensioning force to maintain a consistent normal force between the plug and socket parts, thus preventing self-loosening and ensuring low and constant contact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid bayonet locking mechanism is used to connect plug and socket parts, then a stable mechanical connection is achieved, but the connection loosens spontaneously under vibrations and thermal expansion

Engineering Contradiction:
Improvemechanical connection stabilityVSAvoidconnection reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The locking bolt is made movable along the coupling bolt axis through a guide groove, allowing it to dynamically adjust its position. The spring device enables the locking bolt to move axially, providing dynamic adaptation to thermal expansion and vibration effects while maintaining reliable connection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring device changes the normal force parameter dynamically. By allowing the locking bolt to move along the guide groove, the spring continuously adjusts the compressive force to compensate for loosening effects, maintaining optimal contact pressure between mating surfaces.

Inventive Principle:
Principle #35Parameter changes

2Strength

If solid material plug and socket parts are used, then a rigid connection is achieved, but elastic deformation is insufficient to maintain contact under twisting forces

Engineering Contradiction:
Improveconnection strengthVSAvoidcontact surface stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The spring-loaded locking bolt introduces dynamic elasticity to the otherwise rigid connection. The locking bolt can move axially within the guide groove, allowing the connection to adapt dynamically to twisting forces and maintain stable contact between surfaces.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If a bayonet mechanism generates high normal force for low-resistance electrical connection, then electrical contact resistance is reduced, but the mechanism becomes sensitive to loosening under vibrations

Engineering Contradiction:
Improveelectrical contact resistanceVSAvoidconnection reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The spring device continuously adjusts the normal force parameter to maintain optimal electrical contact. By allowing the locking bolt to move along the guide groove, the spring compensates for loosening effects, ensuring consistently low contact resistance despite vibrations and thermal effects.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If the locking bolt is fixed in position, then the structure is simple, but the normal force decreases under thermal expansion and settling

Engineering Contradiction:
Improvelocking mechanism complexityVSAvoidnormal force
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The locking bolt is made movable along the coupling bolt axis through a guide groove, allowing it to dynamically adjust its position. The spring device enables the locking bolt to move axially, providing dynamic adaptation to thermal expansion and vibration effects while maintaining reliable connection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring device is pre-loaded to continuously apply a compressive force to the locking bolt. This preliminary action ensures that the locking bolt maintains constant contact with the groove walls, generating sufficient friction to prevent loosening before vibrations or thermal effects occur.

Inventive Principle:
Principle #10Preliminary action

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 self-loosening and maintains a stable, low-impedance connection, enhancing the reliability and compatibility of power cable couplings with existing components, reducing the risk of voltage drops and improving welding process stability.

Implementation Method 1

the locking bolt is held in a basic position towards a rear end of the coupling bolt by means of a spring device and when the engagement connection between the plug part and the socket part is established, the locking bolt is moved towards the front end of the coupling bolt by positive locking with the groove in the socket part and the spring device is thereby tensioned to form a preload force

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

both coupling elements, i.e., the plug part and the socket part, are made of solid material according to the prior art, a rigid connection results that remains in the locked position solely due to frictional forces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The described loosening process is caused in practice primarily by mechanical vibrations, by heating of the connectors during operation and the associated thermal expansion, or by settling of the contact surfaces

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3257110B1Coupling for power cables
Publication Date: 2020.12.02 TBI IND
  • EP3257110B1 patent drawingFigure 1~3
  • EP3257110B1 patent drawingFigure 4~8

AI summary

The invention relates to a coupling for power cables, consisting of a plug part (1) and a socket part, wherein the plug part (1) has a basic body (2) with a coupling pin (3) on which a locking pin (4) is arranged, said locking pin being mounted in the plug part (1) so as to be displaceable in the axial direction of the coupling pin (3), wherein the locking pin (4) is held in a basic position in the direction of a rear end (11) of the coupling pin (3) by spring force and, during locking of the coupling, is moved by means of a form fit with a helical groove in the socket part in the direction of a front end (12) of the coupling pin (3) and, in the process, a spring device (16) is tensioned.