Lighting Device Light Guide Retention Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lighting devices with light guides in motor vehicles face issues of partial extraction of the light guide from its housing, leading to disrupted light propagation, and existing solutions like metal staples or elastic lugs fail to securely retain the light guide, causing pivoting and noise or damage.
Innovation Solution
The lighting device incorporates a cylindrical shaft with elastic latching tabs and a radial retaining step, along with a indexing groove system that prevents the housing from pivoting by securely retaining the light guide through a snap-in mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If frictional contact with side walls is used to retain the light guide, then the structure is simple, but the restraint is not sufficient to prevent displacement or exit during violent impact or vibrations
Solution Approach 1:
The patent uses a frustoconical flange with a tapered outer surface that matches the conical inner surface of the receiving shaft. This curved geometric interface provides progressive mechanical engagement, where the light guide is guided into position and then securely retained by the converging walls, preventing displacement and exit during vibration or impact while maintaining structural simplicity.
Solution Approach 2:
The patent employs elastic lugs that can deform elastically during insertion and then return to their original position to provide retaining force. This dynamic elastic behavior allows the retention mechanism to adapt to insertion forces and then maintain secure retention under varying operational conditions including vibration and impact.
2Reliability
If elastic lugs with tangential cutout are used to retain the light guide, then the light guide is securely retained, but the casing pivots around the light guide causing micro-shocks, noise and damage
Solution Approach 1:
The patent introduces asymmetric indexing features: a transverse groove in the receiving shaft and a corresponding protrusion on the light guide that are offset from the centerline. This asymmetric arrangement prevents rotational symmetry, thereby eliminating the pivoting motion that causes micro-shocks and noise while maintaining secure retention through the elastic lugs.
Solution Approach 2:
The indexing groove and protrusion arrangement guides the light guide into a predetermined angular position during insertion, preventing pivoting before the retention mechanism engages. This preliminary positioning action ensures that the light guide is correctly oriented and secured, avoiding subsequent pivoting and associated harmful effects.
3Reliability
If additional components like support plates or metal staples are added to fix the housing, then the light guide retention is improved, but the manufacturing cost and assembly steps increase significantly
Solution Approach 1:
The patent combines multiple functions into the receiving shaft structure itself: the conical inner surface provides guidance and retention, the transverse groove provides indexing, and the elastic lugs provide both retention and positioning. This integration eliminates the need for separate support plates, metal staples, or other additional fixing components, reducing both part count and assembly complexity while maintaining reliable light guide retention.
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 solution effectively prevents the housing from pivoting around the light guide, ensuring stable light propagation and reducing noise and damage, while eliminating the need for additional components and assembly steps, thus reducing costs.
Implementation Method 1
said elastic retaining means comprise two said latching tabs arranged opposite one another and each capable of cooperating with a corresponding lug made on said cylindrical section of the light guide
Implementation Method 2
each said tongue comprises at its free end a tooth protruding from the internal side of said receiving barrel and formed by an inclined ramp extending as far as a radial retaining step
Data Source
Figure 1~4
Figure 5~7
AI summary
The present invention relates to a lighting device comprising a transparent light guide, a housing (30) housing a light source and comprising a receiving socket (31) able to accept a cylindrical portion (22) of the said light guide so as to optically couple it to the said light source, as well as elastic retaining means (33, 23) for retaining the said cylindrical portion (22) of the light guide inside the said receiving socket (31) of the housing (30); the said lighting device also comprising indexing means (36, 24) able to keep the said cylindrical portion (22) of the light guide and the said receiving socket (31) of the housing (30) in a predetermined relative angular position with respect to one another.