Vehicle Headrest Four-Bar Linkage Compact Adjustment

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Solution Overview

Problem

Existing headrest designs for vehicle seats lack a narrow configuration that allows for adjustable height and X-direction movement, limiting their adaptability and space efficiency.

Innovation Solution

A headrest with a gear device and four-bar linkage mechanism, featuring a trapezoidal four-bar linkage design with variable instantaneous axis of rotation, enabling movement between forward and rearward positions without protrusion, and an optional height adjustment device with electric drive and self-locking mechanism for stable and adjustable positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a narrow headrest configuration is used, then space utilization is improved, but adjustability in height and X-direction becomes limited

Engineering Contradiction:
Improveheadrest volumeVSAvoidadjustability
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The headrest employs dynamic adjustment mechanisms including a four-bar linkage system with parallelogram structure that enables the headrest to move in both vertical (height) and horizontal (X-direction) directions. The electric drive system provides dynamic positioning capability, allowing the headrest to transition between multiple positions while maintaining a compact form when not in use.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a four-bar linkage mechanism is used for adjustment, then adjustability is improved, but device complexity increases

Engineering Contradiction:
ImproveadjustabilityVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The four-bar linkage mechanism serves multiple functions simultaneously: it provides both vertical height adjustment and horizontal X-direction movement through its parallelogram configuration. The same linkage system also maintains the headrest's structural stability during movement and enables compact retraction, eliminating the need for separate adjustment mechanisms for each direction.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If the headrest is moved forward toward the seat occupant's head, then user comfort is improved, but the risk of collision increases

Engineering Contradiction:
Improveuser comfortVSAvoidcollision risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The electric drive system incorporates feedback control that monitors the headrest's position and the seat occupant's presence. The system can detect when the headrest approaches the limit of its forward movement range and automatically stops or reverses to prevent collision with the occupant's head, while still allowing comfortable positioning within safe limits.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3360728B1Headrest
Publication Date: 2021.04.14 GRAMMER AG
  • EP3360728B1 patent drawingFigure 1
  • EP3360728B1 patent drawingFigure 2
  • EP3360728B1 patent drawingFigure 3

AI summary

The invention relates to a headrest for a seat, in particular for a vehicle seat, with a head support element (11) which can be mounted on a vehicle seat by means of a bearing device (13), wherein the bearing device (13) comprises a transmission device (18) with a first retaining element (16) associated with the head support element (11) and a second retaining element (17) fixed to the seat part, such that the first retaining element (16) and the second retaining element (17) are connected to each other by links (19a, 19b, 20a, 20b) in such a way that at least one four-joint linkage (27a, 27b) is formed, by means of which the head support element (13) can be moved relative to the vehicle seat between a forward position moved towards the head of a seat occupant and a rearward position moved back.