Cantilever Snap With Slant Protrusion For Low Insertion Force
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Solution Overview
Problem
Existing snap features for joining plastic components often require high installation force, are prone to loose fits due to manufacturing tolerances, and may not provide sufficient holding power, especially in outdoor power equipment where secure and easy assembly is crucial.
Innovation Solution
A snap assembly featuring a cantilever snap with a cantilevered-slant protrusion and a retention body with a holding assembly of step-like protrusions, allowing for low insertion force while providing high pullout force and accommodating manufacturing tolerances through a secure, integrally formed design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional plastic snaps are used to join components, then secure joints can be achieved, but high installation force is required
Solution Approach 1:
The snap feature is divided into two separate components: a snap feature formed in the first component and a retention feature formed in the second component. This segmentation allows each feature to be optimized independently, with the snap feature designed for easy insertion and the retention feature designed to provide secure holding without requiring high installation force.
Solution Approach 2:
The retention feature includes a retention extension that protrudes laterally from the second component, creating a three-dimensional engagement structure. This lateral extension engages with the snap feature in a different dimensional plane, providing secure joint strength while allowing simple linear insertion motion.
2Strength
If conventional snaps are used with tight tolerances to ensure secure fit, then holding power is improved, but manufacturing complexity increases
Solution Approach 1:
The snap feature includes a snap extension with a snap surface that protrudes laterally, creating an interference fit engagement with the retention feature. By changing the geometric parameters to include lateral protrusion and corresponding engagement surfaces, the design achieves secure holding power through geometric interlocking rather than relying on tight dimensional tolerances.
Solution Approach 2:
The snap feature and retention feature have asymmetric geometries where the snap extension protrudes in one direction and the retention extension engages from another direction. This asymmetric design creates a secure fit through directional engagement, making the joint insensitive to variations in manufacturing tolerances while maintaining strong holding power.
3Strength
If hardware is used to join components, then secure joints are achieved, but the number of components increases
Solution Approach 1:
The snap feature and retention feature are formed integrally with their respective first and second components, likely through injection molding or similar processes. This merging eliminates separate hardware components, as the joining features are built-in as part of the component manufacturing process itself, reducing total part count while maintaining joint security.
Solution Approach 2:
The snap and retention features serve multiple functions: they provide mechanical joining, accommodate manufacturing tolerances, and enable assembly without additional hardware. This multi-functionality consolidates what would traditionally require separate hardware elements into the component structures themselves, reducing overall device complexity.
Data Source
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AI summary
A snap assembly may include a cantilever snap and a retention body. The cantilever snap may include an orifice in a surface of a first component. The orifice may be defined between sidewalls. The cantilever snap may further comprise a cantilevered-slant protrusion extending between the sidewalls and out of the orifice at an angle relative to the surface. The retention body may be attached to a second component and configured to be inserted into the orifice from a side of the first component that is opposite of a side of the first component away from which the cantilevered-slant protrusion extends to secure the retention body to the cantilever snap. The retention body may include a retaining extension comprising a holding assembly. The holding assembly may comprise a plurality of teeth that are arrayed to form a series of step-like protrusions that step away from a contact face of the retention body.