Molded Headrest Bearings with Flexible Tabs
Solution Overview
Problem
The existing motor vehicle seat headrest designs with separate metal rods and molded plastic bearings for adjustment and impact absorption incur additional manufacturing costs due to the separate installation of bearings, which also complicates maintaining uniform clamping quality across varying temperatures.
Innovation Solution
The bearings are molded in one piece with the ducts, featuring flexible tabs and U/C-shaped return springs to ensure homogeneous clamping and reduce manufacturing costs, while maintaining effective adjustment and impact absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate bearings are mounted in the box, then the clamping contact quality is maintained, but the manufacturing cost increases
Solution Approach 1:
The patent merges the bearing function directly into the duct structure by molding flexible tabs with bearing functionality integrally into the duct. This eliminates separate bearing components and their installation, reducing manufacturing complexity and cost while maintaining the clamping contact function through the flexible tabs that directly contact the rods.
2Strength
If molded plastic material is used for the box, then impact energy is absorbed, but thermal expansion affects sliding smoothness
Solution Approach 1:
The patent addresses thermal expansion effects by changing the physical parameters of the contact interface. The flexible tabs are designed with specific elasticity and contact pressure characteristics that compensate for dimensional changes in the molded plastic box due to thermal expansion, maintaining consistent clamping force and sliding smoothness across temperature variations.
Solution Approach 2:
The flexible tabs introduce a dynamic element to the otherwise static molded plastic structure. These tabs can elastically deform to accommodate thermal expansion and contraction of the box, maintaining continuous contact with the rods while allowing for dimensional changes without compromising sliding smoothness or clamping quality.
3Adaptability or versatility
If separate rods are used, then transverse expansion is accommodated, but structural stability is reduced
Solution Approach 1:
The patent maintains the segmented rod structure to accommodate transverse expansion, but enhances structural stability through the duct design. The duct provides a stabilizing framework that guides and constrains the separate rods, preventing excessive movement while allowing necessary expansion. The flexible tabs further stabilize the system by providing consistent contact points on each rod.
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 reduces manufacturing costs and ensures consistent clamping quality over a wide temperature range, ensuring smooth sliding and effective impact absorption without the need for separate bearing components.
Implementation Method 1
each of said bearings is provided with a return spring for said corresponding tabs towards said rods, said spring having the general shape of U or C, each of the branches of which bears on each of said tabs so as to pinch said rods between said tabs
Implementation Method 2
a box made of molded plastic material for absorbing energy in the event of a passenger's head impact
Data Source
Figure 1~2a
Figure 2b~3
Figure 4~5a
AI summary
The invention relates to a headrest (1) comprising two rods and a housing (3) having two conduits (4) each receiving one of said respective rods in sliding motion, so as to allow height adjustment of said housing, each of said conduits being provided with an upper bearing (5a) and a lower bearing (5b) both exerting a clamping contact on each of said rods, said bearings being molded as a single unit with said conduits and having at their periphery two flexible tabs (6) opposed in a first direction, each of said bearings being provided with a return spring (8) of said corresponding tabs towards said rods, said spring having a general U or C shape, each of whose branches (9) bears against each of said tabs so as to pinch said rods between said tabs.