Elastic Connecting Flange Captive Screw Retention
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Solution Overview
Problem
Existing electrical connection systems require precise manufacturing tolerances to securely hold screws, leading to high production costs and efforts due to the need for exact coordination of structural dimensions to prevent damage and screw loss.
Innovation Solution
A connection flange with a shaft made of elastic material and a safety device that adapts to the screw's outer circumference, allowing for captive screw reception with different cross-sectional shapes, enabling secure holding without full circumference expansion, and utilizing insulating materials for enhanced elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ribs are provided in the covering housing to captively hold the screw, then the screw is securely held, but the manufacturing tolerances must be very tight and coordination very precise
Solution Approach 1:
The invention changes the geometric parameters of the shaft cross-section along its length, creating an asymmetric profile where the inner circumference at the opening differs from the inner circumference at the bottom. This parameter variation allows the shaft to accommodate the screw head with different clearance requirements at different positions, reducing the need for tight manufacturing tolerances while maintaining reliable captive protection.
Solution Approach 2:
The invention transitions from a uniform circular cross-section (one-dimensional symmetry) to an asymmetric cross-section with different circumferences at different axial positions. This dimensional variation along the shaft's length creates additional design freedom, allowing the screw to be inserted with appropriate clearance while the asymmetric profile prevents removal, thereby reducing manufacturing precision requirements.
2Reliability
If a peripheral rib with smaller free inner diameter than the screw head is provided, then the screw is held captive, but the screw flange can tear off during automatic assembly if expansion forces exceed durability
Solution Approach 1:
The invention applies local quality by creating different cross-sectional characteristics at different locations along the shaft. The opening end has a larger inner circumference that accommodates the screw head with sufficient clearance to prevent excessive expansion forces, while the bottom has a smaller inner circumference that provides captive protection. This localized differentiation allows the screw flange to pass through without tearing while still achieving secure retention.
3Ease of operation
If the shaft wall is made of elastic material to allow deformation during screw insertion, then the screw can be accommodated, but the structural dimensions must still be precisely coordinated
Solution Approach 1:
The invention changes the geometric parameters of the shaft cross-section along its length, creating an asymmetric profile where the inner circumference at the opening differs from the inner circumference at the bottom. This parameter variation allows the shaft to accommodate the screw head with different clearance requirements at different positions, reducing the need for tight manufacturing tolerances while maintaining reliable captive protection.
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 allows for secure screw accommodation with reduced manufacturing precision demands, resulting in cost-effective production while ensuring reliable captive protection and preventing screw loss.
Implementation Method 1
the shaft has a shaft wall made in particular of an elastic material
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a connecting flange for an electric terminal, comprising a housing and a duct provided thereon for receiving a screw, wherein the duct has a duct wall made of an elastic material, on which a safety device is configured such that the screw can be captively received by the duct when not screwed in. A free cross-section of the safety device and the largest cross-section of the screw have different shapes, wherein the length of an interior circumference of the safety device is adapted to the length of the exterior circumference of the screw.