Vehicle Headrest Height Adjustment Rod Deformation

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Solution Overview

Problem

The existing motor vehicle seat headrests with height adjustment mechanisms have a threaded rod that is firmly anchored by the spacer, leading to inadequate energy dissipation in impacts and a risk of head injury from the protruding rod when the headrest is raised, as the rod does not deform to absorb energy and can collide with the occupant's head.

Innovation Solution

A spacer member is used to offset the threaded rod, allowing it to deform and absorb energy during impacts, and ensuring it does not protrude above the spacer regardless of the headrest's height adjustment, thereby preventing collisions with the occupant's head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the threaded rod is firmly anchored by the spacer, then the height adjustment mechanism is stable, but energy dissipation capability is reduced and safety is compromised

Engineering Contradiction:
Improvestability of height adjustment mechanismVSAvoidenergy dissipation capability
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent introduces a receiving means as an intermediary component between the threaded rod and the spacer. This receiving means is fixed to the spacer but allows the threaded rod to move relative to it, thereby mediating between the stability requirement of the spacer and the energy dissipation requirement of the threaded rod. The receiving means enables the rod to deform and absorb energy while maintaining the overall structural stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the threaded rod is firmly anchored by the spacer, then the height adjustment mechanism is stable, but the threaded rod cannot deform to absorb impact energy

Engineering Contradiction:
Improvestability of height adjustment mechanismVSAvoidenergy absorption capability
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent segments the connection between the threaded rod and the spacer by introducing a separate receiving means. This segmentation allows the threaded rod to be decoupled from the rigid spacer structure, enabling it to deform and absorb impact energy independently while the receiving means maintains the overall structural stability through its connection to the spacer.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the housing is raised to maximum-high position, then height adjustment function is achieved, but the threaded rod protrudes above the spacer creating safety risk

Engineering Contradiction:
Improveheight adjustment functionVSAvoidrisk of head injury from protruding rod
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The receiving means acts as a pre-designed constraint that beforehand prevents the threaded rod from protruding above the spacer, even when the housing is in the maximum-high position. This prior cushioning approach eliminates the safety risk of head injury by ensuring the rod remains contained within the housing boundaries throughout the full range of height adjustment.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enhances energy absorption and safety by allowing the threaded rod to deform and reducing the risk of head injury from the rod, ensuring it remains below the spacer even at maximum height adjustments, thus improving occupant safety during impacts.

Implementation Method 1

the threaded rod, which extends behind said face, presents a very firm anchoring point not conducive to energy dissipation

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3409536B1Headrest for a motor vehicle seat
Publication Date: 2021.12.08 TESCA FRANCE
  • EP3409536B1 patent drawingFigure 1a~1b
  • EP3409536B1 patent drawingFigure 2a~2b

AI summary

The invention relates to a headrest (1) comprising: a metal frame (2) defining two arms (3) and a spacer (4); a housing (5) comprising two conduits (6) for receiving said sliding rods; a height adjustment device for said housing relative to said rods, comprising: an electric motor (8) fixed to said housing; a vertical threaded rod (9) mounted for rotation in said housing in cooperation with said motor; a receiving means (10) for said rod through a threaded orifice (11) provided in said means, said means being fixed to said spacer, said means being fixed to said spacer by means of a spacing member (12) offsetting it downwards relative to said spacer, so that said rod is not substantially protruding above said spacer when said housing is adjusted to the maximum-height position.