Lug Retention Arrangement With Moveable Protrusion

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Solution Overview

Problem

Existing lug assembly systems for electrical power distribution devices require tools for tightening and lack a mechanism for easy removal and reinstallation, leading to increased assembly time and potential errors, as well as the need for torque wrenches for quality assurance, and result in the entire device needing replacement if the lug screw is damaged.

Innovation Solution

A lug arrangement with a moveable protrusion in the lug retainer that can be inserted and secured by hand without tools, allowing for easy attachment and detachment from the terminal, eliminating the need for torque wrenches and enabling tool-free assembly and reassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a threaded fastener element is used to attach a lug to a terminal, then the lug can be securely attached, but tools and torque wrenches are required for tightening and quality assurance

Engineering Contradiction:

Improvesecure attachmentVSAvoidtool-free assembly

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The lug retainer incorporates a resilient body with moveable protrusions that can deflect during insertion and then return to a locked position, providing dynamic movement that enables tool-free attachment while maintaining secure connection. The protrusions move from a first position during insertion to a second position that engages with the lug, creating a reliable attachment without requiring threading tools.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The resilient body with moveable protrusions automatically engages with the lug upon insertion, eliminating the need for external tools or torque wrenches. The system self-secures through the elastic deformation and recovery of the resilient material, allowing the attachment mechanism to service itself without external intervention.

Inventive Principle:

Principle #25Self-service

2Reliability

If the lug is molded into the housing, then the lug is securely held, but the lug cannot be removed if the screw is damaged

Engineering Contradiction:

Improvesecure holdingVSAvoidremovability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The attachment system is divided into separate components: the lug retainer, the resilient body with protrusions, and the lug itself. This segmentation allows the lug to be independently attached and detached from the housing, providing removability while maintaining secure holding during operation. The modular design enables replacement of individual components without replacing the entire assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resilient body provides a dynamic attachment mechanism that secures the lug during operation but allows for controlled removal when needed. The elastic properties enable the connection to be firm during use yet reversible when the retainer is deliberately actuated, providing both secure holding and removability.

Inventive Principle:

Principle #15Dynamics

3Reliability

If conventional fasteners are used, then the lug can be attached, but assembly time is increased due to tool requirements

Engineering Contradiction:

Improveattachment capabilityVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces the conventional threaded mechanical fastening system with an elastic deformation-based retention mechanism. Instead of using screws and threads that require rotational tools, the system uses the elastic recovery of the resilient body to create a secure attachment, substituting a simpler insertion motion that requires no tools and reduces assembly time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution simplifies the attachment process, reduces assembly time, and allows for easy removal and reinstallation of the lug retainer, enhancing manufacturing efficiency and reducing the likelihood of errors while maintaining secure electrical connections.

Implementation Method 1

the protrusion is moveable from a first position to a deflected position for enabling insertion of the lug retainer into the second hole

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The lug screw is then tightened to compress the conductor against the terminal and to prevent the conductor from being pulled from the lug assembly during normal use

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS9270033B2Lug retention arrangement

Publication Date: 2016.02.23 SIEMENS DE C V

AI summary

A lug arrangement for electrically connecting a conductor to a terminal of a circuit breaker. The lug arrangement includes a lug having a lug opening and first and second holes. The lug opening includes an opening for receiving the conductor and a slot for receiving the terminal. The lug arrangement includes a lug screw threadably engaged with the first hole for compressing the conductor against the terminal. Further, the lug arrangement includes a lug retainer for insertion into both the second hole and a third hole formed in the terminal. The lug retainer includes at least one protrusion that is moveable from a first position to a deflected position for enabling insertion of the lug retainer into the second hole. The at least one protrusion is also moveable back to the first position wherein the protrusion engages the second hole to attach the lug retainer to the lug.