Screwless Clamp Terminals for Stable Wire Connections

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Solution Overview

Problem

Existing electrical wire terminations in screw and clamp type connections are prone to strand relaxation, leading to increased resistance and overheating due to copper wire heating and cooling, necessitating re-torqueing, which is costly and inefficient.

Innovation Solution

A screwless connection terminal system using a clamp spring mechanism that moves between open and closed positions to securely clamp wires, ensuring a constant and continuous electrical connection without the need for screws, thereby reducing strand relaxation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If screw and clamp type terminations are used, then electrical connection can be established, but strand relaxation occurs leading to increased resistance and overheating

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidconnection tightness

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs a spring-loaded terminal design where a compression spring continuously applies force to the contact finger, maintaining dynamic pressure on the wire connection. This dynamic mechanism compensates for strand relaxation by automatically adjusting to wire movement and thermal expansion, preventing loosening that occurs with static screw connections.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The spring-loaded terminal is designed to self-adjust and maintain connection integrity without external intervention. The compression spring automatically compensates for wire movement, thermal cycling, and strand relaxation, eliminating the need for re-torqueing that is required with traditional screw connections.

Inventive Principle:

Principle #25Self-service

2Ease of manufacture

If direct pressure type terminations are used, then installation is simple, but wires can be cut or nicked causing poor electrical connections

Engineering Contradiction:

Improveinstallation simplicityVSAvoidelectrical connection quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a contact finger as an intermediary element between the compression spring and the wire. This contact finger gently guides and secures the wire without direct crushing pressure, preventing wire damage while maintaining secure connection. The spring-loaded mechanism provides controlled pressure distribution that avoids concentration points that could cut or nick the wire.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If screw and clamp type terminations are used, then wire clamping is achieved, but re-torqueing is necessary increasing installation costs

Engineering Contradiction:

Improveconnection securityVSAvoidmaintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The compression spring provides continuous force to maintain connection tightness throughout the operational life of the device. This continuous active pressure ensures that the electrical connection remains secure and stable, preventing the gradual loosening that occurs with static screw connections over time.

Inventive Principle:

Principle #20Continuity of useful 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 screwless connection terminals provide a stable and reliable electrical connection that maintains low resistance over time, eliminating the need for re-torqueing and reducing installation costs.

Implementation Method 1

a clamp spring secured to the clamp brace. The clamp spring is movable relative to the clamp brace between a closed position where a wire can be clamped between the clamp spring and the clamp brace

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12586933B2Electrical wiring devices with screwless connection terminals

Publication Date: 2026.03.24 HUBBELL INC

AI summary

Electrical wiring devices that incorporate clamp-type wire terminal connections are described. The electrical wiring devices include for example, single and duplex blade-type electrical receptacles, blade-type locking electrical receptacles, single or multi-pole electrical switches, combination switches and blade-type receptacles, blade-type plugs for electrical cords and blade-type connectors for electrical cords. The electrical wiring devices include a plurality of contact assemblies. Each contact assembly includes a wire terminal and a plunger.