Terminal Fitting Lance Clearance Design
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Solution Overview
Problem
Existing terminal fittings face issues with insufficient engagement margin due to the length of the locking lance, which can lead to the lance not being inserted deeply enough and potentially coming out of the lance hole, especially when the contact portion is closely aligned with the outer wall, limiting versatility and secure retention.
Innovation Solution
A terminal fitting design with a recess in the contact portion and a clearance between the outer wall and contact portion allows the locking lance to be inserted deeply, reducing the likelihood of it coming out, and includes a second lance hole for inverted insertion, enhancing engagement margin and versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking lance is made longer to improve engagement margin, then the engagement margin is improved, but the locking lance cannot be inserted deeply enough and may come out of the lance hole
Solution Approach 1:
The patent introduces a clearance dimension between the outer wall and contact portion, creating a new spatial dimension for the locking lance to escape into. This allows the lance to achieve deeper effective engagement without increasing its overall length, resolving the contradiction between engagement margin and lance length.
2Volume of moving object
If the contact portion is positioned close to the outer wall to reduce space, then the compactness is improved, but the locking lance cannot be inserted deeply into the lance hole
Solution Approach 1:
The patent segments the internal space by creating a dedicated clearance zone between the outer wall and contact portion. This segmentation allows the locking lance to have a separate escape path that does not interfere with the compact contact portion positioning, thereby maintaining both compactness and sufficient insertion depth.
3Reliability
If the recess is formed deep in the contact portion to increase engagement margin, then the engagement margin is improved, but the insertion space for the male tab is reduced
Solution Approach 1:
The patent moves the engagement enhancement from the horizontal dimension (deep recess into male tab space) to the vertical dimension (clearance between outer wall and contact portion). This dimensional shift allows the locking lance to achieve deeper engagement without encroaching on the male tab insertion space.
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
Ensures a sufficient engagement margin for the locking lance, allowing for deeper insertion and reduced likelihood of ejection, while maintaining an adequate insertion space for the male tab and enabling versatile orientation of the terminal fitting.
Implementation Method 1
A resiliently deformable contact piece is formed in the main portion and can be held resiliently in contact with the male tab
Implementation Method 2
A resiliently deformable locking lance is formed at an inner wall of the cavity and a tip part of the locking lance engages a rear edge of the main portion from behind when the terminal fitting is inserted properly into the cavity of the housing
Data Source
AI summary
A terminal fitting (10) includes a tubular main portion (11) into which a mating male tab (91) is insertable. A resiliently deformable contact piece (22) which is to be resiliently held in contact with the male tab 91 is formed in the main portion (11), and a contact portion (32) which receives the male tab (91) is formed fixedly at a position facing the resilient contact piece (22). A ceiling wall (19) is at a position opposite to the resilient contact piece outward of the contact portion (32). A ceiling wall lance hole (27) penetrates through the ceiling wall (19) and can receive a locking lance (64) for retaining the terminal fitting (10) in a connector (60). A clearance (33) is formed between the ceiling wall (19) and the contact portion (32) for allowing the entry of the locking lance (54).