Spring Terminal Block Longitudinal Contact Ribs
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Solution Overview
Problem
Spring-loaded terminal connections face challenges in achieving a high clamping force while minimizing insertion force, particularly for thin conductors, and often result in conductor twisting and increased insertion force due to transverse edges, leading to instability and buckling.
Innovation Solution
A spring force connection terminal with a busbar and torsion spring featuring a two-dimensionally extended contact surface formed by contact ribs parallel to the conductor's insertion direction, which reduces twisting and maintains high clamping force, using a U-shaped torsion spring with a clamping leg that extends in the insertion direction and a dielectric housing with a conductor insertion funnel to guide the conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a transverse edge is used to form the contact point, then the contact force is maximized and current transfer is improved, but the conductor can be easily twisted and the insertion force increases
Solution Approach 1:
The patent transitions from a transverse edge contact (one-dimensional line contact perpendicular to insertion direction) to a longitudinal contact surface (two-dimensional surface contact parallel to insertion direction). The contact surface extends in the insertion direction, allowing the conductor to rest against it over an extended length, which reduces insertion force while maintaining clamping force through the combination of contact surface friction and spring pressure.
Solution Approach 2:
The patent applies different functional qualities to different parts of the contact interface. The contact surface provides a smooth, extended area for low-friction insertion, while the clamping leg provides concentrated spring force for secure holding. This local differentiation allows the insertion path to have low resistance while the clamping function maintains high force.
2Force
If a transverse edge is used to form the contact point, then the contact force is maximized, but the conductor stability is impaired due to twisting
Solution Approach 1:
By extending the contact surface in the longitudinal direction (parallel to conductor axis), the patent creates a stabilizing effect that resists twisting movements. The extended contact area distributes forces along the conductor length, preventing the concentrated stress points that cause twisting with transverse edge contacts.
Solution Approach 2:
The contact surface acts as an intermediary between the clamping leg and the conductor, providing a distributed interface that reduces stress concentration. Instead of a sharp transverse edge creating localized stress, the extended surface distributes the clamping force along the conductor length, maintaining stability.
3Manufacturing precision
If a transverse edge is used, then the contact point is well-defined, but the insertion process becomes scratchy and jerky
Solution Approach 1:
The patent replaces the transverse edge geometry with a longitudinal contact surface geometry. This dimensional change transforms the insertion interaction from a point/line contact that causes jerky motion to a surface contact that provides continuous, smooth guidance throughout the insertion process.
4Reliability
If high clamping force is applied, then contact reliability is improved, but thin conductors may buckle during insertion
Solution Approach 1:
The extended contact surface provides preliminary support and guidance to the conductor during insertion, before the full clamping force is engaged. This preliminary action prevents buckling by distributing insertion forces along the conductor length, allowing high clamping force to be applied safely after smooth insertion.
Solution Approach 2:
By changing from transverse to longitudinal contact surface orientation, the patent provides distributed support along the conductor axis during insertion, preventing buckling while enabling subsequent high clamping force application for reliable contact.
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 solution provides a stable and secure connection with reduced insertion force, preventing conductor twisting and buckling, while ensuring reliable contact and easy insertion, even with repeated use.
Implementation Method 1
a torsion spring (42) which exerts a clamping force on the stripped conductor end piece (16)
Implementation Method 2
a torsion spring (42) with a clamping leg (44) which extends in the direction of insertion (E)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a spring terminal block, comprising a bus bar and a leg spring for connecting a stripped conductor end piece of an electric conductor, wherein the conductor end piece is inserted into a material passage of the bus bar and is clamped by means of the leg spring. According to the invention, the contact surface on the metal collar of the inner wall surface of the material passage comprises contact ribs extending along the direction of insertion, in order to form a line-shaped contact pattern extending in the direction of insertion.