Breakaway Pressure Screw Torque Limiting Mechanism
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Solution Overview
Problem
Existing electrical connectors face challenges in securely attaching conductors without damaging them and in preventing over-tightening, which can lead to inferior connections and conductor damage.
Innovation Solution
A fastener design featuring a head, shaft, and pressure pad with shearable and breakaway portions that allow for controlled torque limits, preventing over-tightening and minimizing conductor damage by allowing the pressure pad to rotate independently of the shaft, thus reducing friction and preventing grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fastener is used to provide compression force to attach and retain a conductor, then secure attachment is achieved, but over-tightening can occur causing conductor damage
Solution Approach 1:
The patent incorporates a shearable section with a predetermined torque limit that will fail at a specific torque threshold. This preliminary design feature ensures that when the fastener is tightened, the shearable section will break away if the torque exceeds the safe limit, preventing conductor damage before it occurs. The breakaway feature acts as a pre-set safety mechanism that limits the maximum compression force applied to the conductor.
2Reliability
If a fastener is tightened to secure a conductor, then attachment reliability is improved, but friction and grinding can damage the conductor
Solution Approach 1:
The pressure pad is designed with a breakaway portion that disconnects from the shaft at a predetermined torque limit. This preliminary design ensures that once the safe torque threshold is reached, the pressure pad can rotate independently of the shaft, preventing further grinding friction on the conductor while maintaining the secure attachment already achieved.
Solution Approach 2:
The fastener is divided into segments that can move independently - specifically, the pressure pad can rotate independently of the shaft after the breakaway portion fails. This segmentation allows the pressure pad to maintain contact with the conductor for secure attachment while eliminating the relative rotation that causes grinding friction and conductor damage.
3Reliability
If a fastener design with breakaway portions is used, then over-tightening prevention is achieved, but device complexity increases
Solution Approach 1:
The fastener is segmented into distinct components (head, shaft, pressure pad) connected by shearable sections with predetermined torque limits. This segmentation allows each component to perform its specific function while the breakaway features provide automatic over-tightening protection. The complexity is managed by making each segment relatively simple in design.
Solution Approach 2:
The breakaway portions are designed to fail automatically at predetermined torque limits without requiring external monitoring or control systems. The fastener itself provides the over-tightening prevention through its own structural features, eliminating the need for separate torque control mechanisms or special tools, thus limiting the increase in overall system complexity.
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 fastener design ensures secure conductor attachment while preventing damage and eliminating the need for special torque wrenches, accommodating various conductor sizes with adjustable torque settings.
Implementation Method 1
The shearable section has a first torque limit. A pressure pad is connected to the shaft by a breakaway portion having a second torque limit... The fastener is rotated until the second torque limit is reached, fracturing the breakaway portion and allowing the pressure pad to rotate with respect to the shaft.
Data Source
AI summary
A fastener includes a head, a shaft, and a pressure pad. The head has an outer surface for engaging a drive tool. The shaft has an outer surface including a threaded portion. The pressure pad has a breakaway portion with a torque limit connecting the pressure pad to the shaft.