Mechanical Wire Lug Clamping for Small-Wire Pull-Out Resistance
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Solution Overview
Problem
Traditional mechanical lugs fail to properly center and secure smaller diameter wires, leading to pull-out failures and loosening due to thermal elongation, especially for solid, stranded, and concentric wires.
Innovation Solution
A mechanical lug design with a wire receptacle bore featuring converging clamping surfaces and a wire binding screw (WBS) that includes a circumferential rim and end pocket to secure the wire, accommodating various wire types and sizes, and maintaining clamping even under thermal cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard circular bore is used in traditional lugs, then the lug structure is simple, but smaller diameter wires are not properly centered and secured, leading to pull-out failures
Solution Approach 1:
The patent applies asymmetry by changing the bore cross-section from a standard circular shape to an asymmetric shape with converging clamping surfaces. These surfaces are positioned and angled to specifically center and secure smaller diameter wires, creating an asymmetric wire support surface that adapts to the wire diameter and prevents pull-out failures while maintaining structural simplicity
2Reliability
If traditional lug design is used, then manufacturing is simple, but thermal elongation creates mechanical gaps or loosening that reduce preload on the wire
Solution Approach 1:
The patent applies parameter changes by modifying the bore geometry parameters - specifically creating converging clamping surfaces with specific angles and positions. This geometric parameter change allows the bore to maintain proper wire centering and clamping force during thermal cycling, compensating for thermal elongation effects without complicating the manufacturing process
3Ease of operation
If the bore is larger than the wire diameter, then the wire can be inserted easily, but the wire is not properly centered under the WBS, especially for smaller wires
Solution Approach 1:
The patent applies dimensionality change by transitioning from a standard circular bore (one-dimensional symmetry) to a bore with converging clamping surfaces that create a tapered, asymmetric geometry. This dimensional change in the bore profile enables automatic wire centering through the converging surfaces while maintaining easy wire insertion, effectively solving both the ease of operation and manufacturing precision requirements
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 design ensures secure clamping of wires, preventing pull-out failures and maintaining grip during thermal expansion, accommodating a range of wire sizes and types, including solid, stranded, and concentric wires.
Implementation Method 1
The circumferential rim and the end pocket can be configured to deform a section of a wire in the wire receptacle bore so that the circumferential rim presses into the wire and a portion of the wire extends radially outward relative to the rim along the screw axis, into the end pocket to secure the wire in the lug body
Implementation Method 2
Thermal elongation has a negative effect on the ability of a traditional lug to continue to have a suitable grip on a wire during thermal cycling of the lug and wire. A mechanical gap or loosening can be created by thermal elongation of lug body and the WBS.
Data Source
AI summary
A mechanical lug includes a lug body. The lug body defines a wire receptacle bore therethrough along a wire axis from a first face of the lug body to a second face of the lug body opposite the first face. The lug body also defines a WBS bore extending from a third face of the lug body into the wire receptacle bore along a screw axis that is lateral to the wire axis. The wire receptacle bore has a cross-sectional shape relative to the wire axis that includes opposed clamping surfaces that converge toward one another in a direction away from the WBS bore. The clamping surfaces are configured to clamp a wire urged into the opposed clamping surfaces by a WBS in the WBS bore.