Pivoting Headrest Locking for Comfort and Whiplash Protection

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Solution Overview

Problem

Existing headrests for heavy-duty vehicles do not adequately address the balance between comfort and safety in preventing whiplash injuries during rear-end collisions, particularly at low impact velocities, as they lack intuitive and effective adjustment mechanisms for optimal positioning.

Innovation Solution

A headrest design featuring a mounting part secured to the backrest with a rotatable resting part and a locking device actuated by a control rod, combined with an urging device such as a tension spring, allowing for intuitive adjustment between forward and rearward positions to optimize both comfort and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the headrest is designed with a locking device that allows multiple positions, then the adaptability for different users is improved, but the device complexity increases due to additional locking mechanisms

Engineering Contradiction:
Improveheadrest position adaptabilityVSAvoidlocking device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The headrest is designed with a rotatable frame that can dynamically change position between forward most and rearward most positions. The locking device enables the frame to be locked at multiple intermediate positions along an arcuate path, providing adaptability while maintaining a relatively simple mechanical structure through rotational movement rather than complex multi-axis adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism is segmented into discrete locking positions corresponding to specific headrest angles. The control rod interacts with abutment surfaces at different locations to provide distinct locked positions, allowing the continuous rotational movement to be divided into manageable discrete states that are easy to control and maintain.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the headrest allows free adjustment to any position, then the ease of operation is improved, but the stability of the headrest position deteriorates due to potential slippage or unintended movement

Engineering Contradiction:
Improveheadrest adjustment easeVSAvoidheadrest position stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The headrest frame rotates about a pivot axis, allowing smooth dynamic adjustment between positions. The locking device provides intermittent stabilization at specific angles along the rotation path, combining the ease of continuous adjustment with the stability of discrete locked positions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The urging device, configured as a tension spring, performs preliminary action by continuously urging the resting part toward the forward most position. This pre-applied force ensures that when the user releases the control rod, the headrest automatically returns to or remains at the forward most position, preventing unintended rearward movement and enhancing position stability.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the headrest is positioned at the rearward most position for comfort, then the comfort for the user is improved, but the safety in preventing whiplash injuries deteriorates

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

Solution Approach 1:

The headrest frame can rotate dynamically between forward most and rearward most positions, allowing users to adjust based on their comfort needs. The locking device enables the frame to be securely held at any intermediate position, including the forward most position for safety or rearward most position for comfort, providing flexible adaptation to different user requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The headrest position is adjusted by changing the angular parameter of the frame rotation about the pivot axis. By varying this angular parameter between different locked positions, users can optimize the balance between comfort (rearward position) and safety (forward position) according to their specific needs.

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If the urging device strongly urges the resting part towards the forward most position, then the safety in preventing whiplash is improved, but the ease of adjustment to rearward positions deteriorates

Engineering Contradiction:
Improvewhiplash injury preventionVSAvoidadjustment to rearward position
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The urging device applies a preliminary force toward the forward most position to ensure safety. However, when the user actuates the control rod to the adjustment position, the locking mechanism disengages, temporarily overcoming the urging force and allowing easy adjustment to rearward positions for comfort. The system thus provides strong urging for safety during normal use while allowing easy override when adjustment is needed.

Inventive Principle:
Principle #10Preliminary action

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 headrest ensures simple and effective adjustment to the best position for both comfort and safety, reducing the likelihood and severity of whiplash injuries by ensuring the resting part is positioned optimally relative to the user's head, thereby enhancing user safety during rear impact collisions.

Implementation Method 1

The urging device may comprise an elastically deformable member arranged between the mounting part and the resting part to elastically return the resting part towards the forward most position.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The elastically deformable member may be a tension spring having opposite ends attached respectively to anchoring elements of the mounting part and the resting part

Methodology Applied
Scientific EffectTension spring: Spring

Data Source

PatentEP4245604A1Headrest, seat, vehicle and method for adjusting a position of a headrest
Publication Date: 2023.09.20 VOLVO TRUCK CORP
  • EP4245604A1 patent drawingFigure 1~2
  • EP4245604A1 patent drawingFigure 3
  • EP4245604A1 patent drawingFigure 4

AI summary

Headrest (10) comprising: - a mounting part (11), - a resting part (20) comprising a frame (21) mounted on the mounting part (11) in a rotatable manner about a pivot axis (P) between a forward most position and a rearward most position, - a locking device (30) comprising a control rod (31) configured to be actuated by a user so as to move between a locked position in which the resting part (20) is prevented from moving with respect to the mounting part (11), and an adjustment position in which the resting part (20) is allowed to move with respect to the mounting part (11), - an urging device (45) configured to urge the resting part (20) is towards the forward most position.