Self-Gapping Electrical Terminal With Dual Spring-Rate Contact Frame
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Solution Overview
Problem
Existing electrical terminals face challenges in achieving optimal gap dimensions between contact frames, leading to either excessive engagement force, which can damage the terminal, or insufficient contact force, resulting in intermittent connections, and require frequent tool adjustments due to narrow tolerances.
Innovation Solution
The electrical terminal features a self-gapping contact-frame design with a lower contact-frame that includes opposed-tabs and embossments, allowing for controlled gap dimensions and reduced engagement force through dual spring-rate behavior, eliminating the need for visual inspection and improving forming efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional contact-frame design is used, then manufacturing simplicity is maintained, but gap dimension control is poor leading to excessive engagement force
Solution Approach 1:
The contact frame is segmented into multiple functional regions: a body portion, opposed tabs extending from the body, and embossments formed on the tabs. This segmentation allows each region to perform its specific function - the body provides structural support, the tabs provide engagement surfaces, and the embossments create spring-rate variation. The segmentation enables precise control of gap dimensions and engagement force without requiring complex external adjustment mechanisms.
Solution Approach 2:
The embossments create local variations in material thickness and stiffness within the contact frame structure. By strategically placing these embossments on the tabs, the design achieves different spring rates in different regions of the same component. This local quality differentiation allows the contact frame to exhibit dual spring-rate behavior - stiffer in regions requiring stability and more compliant in regions requiring flexibility - thereby controlling engagement force without increasing overall device complexity.
2Manufacturing precision
If narrow tolerance gaps are used, then contact precision is improved, but tool adjustments become frequent
Solution Approach 1:
The contact frame structure performs self-adjustment during the forming process. The embossments create regions of varying stiffness that allow the tabs to naturally flex and accommodate dimensional variations. This self-service mechanism compensates for normal manufacturing tolerances, eliminating the need for frequent tool adjustments while maintaining precise gap dimensions. The structure essentially forms its own adjustment mechanism through its geometric design.
Solution Approach 2:
The embossments fundamentally change the mechanical parameters of the contact frame by creating local stiffness variations. This parameter change transforms the contact frame from a rigid structure requiring precise control to a compliant structure that can absorb dimensional variations. The dual spring-rate behavior emerges from these parameter changes, allowing the system to maintain manufacturing precision without sacrificing productivity.
3Reliability
If high engagement force is applied, then connection reliability is improved, but terminal damage risk increases
Solution Approach 1:
The contact frame transitions from a static rigid structure to a dynamic compliant structure through the embossments. The dual spring-rate behavior allows the tabs to deflect and absorb energy during engagement, creating a more controlled and progressive force application. This dynamic response ensures reliable connection through controlled deformation while preventing excessive peak forces that could damage the terminal, effectively decoupling connection reliability from terminal durability concerns.
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 design reduces engagement force by 30-60% and maintains a contact-force-to-engagement-force ratio of less than 2:1, ensuring reliable electrical connections while simplifying the manufacturing process by eliminating the need for precise visual gap monitoring.
Implementation Method 1
dual spring-rate behavior
Data Source
AI summary
An electrical-terminal includes a wire-attachment-end and a connection-end. The wire-attachment-end is configured to receive a wire-cable. The connection-end is opposite the wire-attachment-end. The connection-end has a top-wall, a bottom-wall, a left side-wall, and a right side-wall forming generally a rectilinear-shape and defining a cavity configured to receive a corresponding electrical-terminal inserted along a mating-axis. The connection-end includes an upper contact-frame and a lower contact-frame disposed within the cavity. The lower contact-frame terminates at a tip that is reversed 180-degrees such that the tip is disposed between the lower contact-frame and the bottom-wall. The lower contact-frame defines an inner-contact having a free-end disposed within a perimeter of the lower contact-frame. The lower contact-frame includes opposed-tabs disposed within opposed-windows defined by the left side-wall and the right side-wall. The opposed-tabs engage the opposed-windows when the corresponding electrical-terminal is inserted, thereby inhibiting a deflection of the lower contact-frame.