LED Support Isostatic Positioning for Tolerance-Relaxed Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positioning devices for light-emitting diodes (LEDs) in lighting and signaling devices require tight manufacturing tolerances due to over-constrained positioning, leading to inaccuracies and increased manufacturing complexity.
Innovation Solution
An isostatic positioning device with specific recess and projection configurations, such as semi-circular or quarter-circle shapes, with defined diameter differences and alignment/offsets, to ensure precise LED support positioning with reduced manufacturing constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two semi-circular recesses of the same diameter are used for positioning, then the positioning structure is symmetric and simple, but the device becomes over-static requiring very tight manufacturing tolerances
Solution Approach 1:
The patent applies asymmetry by making the two recesses have different diameters. The first recess has a diameter equal to the projection diameter, while the second recess has a larger diameter. This asymmetric configuration creates an isostatic positioning system that determines all degrees of freedom without over-constraint, thereby reducing manufacturing tolerance requirements compared to symmetric designs.
2Manufacturing precision
If tight manufacturing tolerances are imposed on recess and protrusion dimensions, then positioning precision is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the geometric parameters of the positioning features, specifically making the second recess have a larger diameter than the first recess. This parameter modification transforms the positioning system from over-constrained to isostatic, allowing for larger manufacturing tolerances while maintaining positioning accuracy, thus reducing manufacturing difficulty and cost.
3Ease of manufacture
If the distance between two recesses is not precisely controlled, then manufacturing is easier, but the relative positioning offset between deflector and light source becomes excessively large
Solution Approach 1:
The patent segments the positioning function into two independent pairs of reliefs rather than relying on a single constrained relationship. Each pair independently determines a degree of freedom, with the asymmetric diameters ensuring proper positioning without requiring precise control of the distance between recesses, thereby decoupling manufacturing ease from positioning accuracy.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a relative positioning device for two parts, each consisting of a light-emitting diode (LED) support (5) and a support element (3) for this light-emitting diode. The device comprises two pairs of interlocking ridges, each pair having at least one recess (5A, 5B) on one part and at least one rounded referencing projection (3A, 3B) on the other part. Each projection is designed, in the assembled position, to rest against the bottom of its corresponding recess in a corresponding insertion direction. According to the invention, the positioning device is isostatic.