Screwless Wire Terminals With Spring Clamping for Stable Contact
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Solution Overview
Problem
Existing electrical wire terminations, such as direct pressure and screw and clamp types, are prone to issues like wire cutting, nicking, and strand relaxation, leading to poor connections and increased resistance, which can cause overheating, and require re-torquing to maintain contact.
Innovation Solution
The development of screwless connection terminals with a clamp spring mechanism that uses a plunger to apply a constant load to the wire terminal, ensuring secure connection and reducing strand relaxation through a movable clamp spring that can be easily opened and closed for wire insertion and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct pressure type terminations are used, then the connection is simple to install, but the wire can be cut or nicked leading to poor electrical connections
Solution Approach 1:
The patent introduces a terminal screw as an intermediary component between the wire and the clamp. The terminal screw applies distributed pressure through a larger contact area, preventing direct cutting or nicking of the wire while maintaining secure electrical connection. The screw mechanism allows controlled application of force without the concentrated pressure point that causes wire damage in direct pressure terminations.
2Reliability
If terminal screws are tightened to prevent strand relaxation, then connection stability improves, but installation complexity and re-torquing requirements increase
Solution Approach 1:
The spring-loaded clamp mechanism is self-adjusting and maintains optimal clamping force automatically without requiring installer intervention for torque adjustment. The spring's inherent elasticity provides continuous pressure compensation as wire strands relax or expand thermally, making the system self-regulating. This eliminates the need for precise torque specifications and subsequent re-torquing operations.
3Ease of operation
If conventional terminations are used, then initial connection is achieved, but resistance increases over time due to heating and cooling cycles
Solution Approach 1:
The spring-loaded mechanism provides continuous feedback through its elastic deformation. As the wire heats and expands or cools and contracts, the spring automatically adjusts its compression force to maintain constant contact pressure. This closed-loop mechanical feedback system compensates for thermal cycles in real-time, preventing resistance increases that occur with fixed-torque screw connections.
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 provides a secure, reliable electrical connection that minimizes wire damage and strand relaxation, maintaining low resistance over time without the need for re-torquing, thus reducing installation costs and improving connection reliability.
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
Implementation Method 2
The plunger is interactive with the clamp spring such that movement of the plunger in a first direction relative to the clamp brace causes the plunger to apply a mechanical load to the clamp spring
Data Source
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.