Seat Height Adjustment with Rigid Gas Spring and Stable Guidance

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Solution Overview

Problem

Existing seat height adjustment devices for recliner chairs lack comfort and stability, often producing unwanted noises and requiring more space, unlike office chairs which have different design constraints.

Innovation Solution

A compact and stable seat height adjustment device using a rigidly locking gas pressure spring with a guide mechanism, featuring a displaceable and stationary part design, and a fastening mechanism, made from materials like metal or bronze, to ensure smooth and noise-free height adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional height adjustment device is used in recliner chairs, then the device can provide height adjustment functionality, but it produces unwanted noises and yields when the user leans backwards

Engineering Contradiction:
Improvestability during height adjustmentVSAvoidunwanted noises and yielding
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The gas pressure spring is designed with dynamic locking characteristics that adapt to different usage states. During normal sitting, the spring provides smooth height adjustment. When the user leans backwards, the locking mechanism engages to prevent yielding and noise, transforming the system from a purely dynamic adjustment mechanism to a locked stable state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The device changes its mechanical parameters (locking force, stiffness) based on the usage condition. The rigidly locking gas pressure spring alters its effective spring constant and locking characteristics depending on whether the seat is being adjusted or bearing the user's weight during reclining, thereby eliminating noise and yielding during the recline phase.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the guide means is made of metal to increase stability, then the device becomes more stable, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvedevice stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The guide means is divided into multiple functional segments: guide surfaces for directional movement, locking surfaces for engagement, and bearing surfaces for load transmission. This segmentation allows each part to be optimized for its specific function while maintaining overall stability, and simplifies manufacturing by allowing modular production of guide components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide means utilizes composite construction combining metal components for structural stability with engineered plastic or bronze elements for low-friction guidance. This composite approach maintains the required device stability while reducing manufacturing complexity compared to all-metal construction, as the non-metallic components can be molded rather than machined.

Inventive Principle:
Principle #40Composite materials

3Volume of moving object

If the height adjustment means is made compact with parts arranged inside interior spaces, then the installation space is reduced, but the device complexity increases

Engineering Contradiction:
Improveinstallation spaceVSAvoidstructural complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The height adjustment means employs a nested configuration where the first part of the adjustment mechanism is positioned inside the interior space defined by the second part. The guide means is integrated within the housing structure, and the gas pressure spring is housed within the adjustment mechanism assembly. This nesting dramatically reduces the overall installation volume while maintaining functional simplicity through hierarchical integration.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Stability of the object's composition

If the guide means is made of bronze for stability and smooth guidance, then the device stability and guidance quality improve, but the manufacturing cost increases

Engineering Contradiction:
Improveguidance stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Bronze or other high-quality low-friction material is applied only to the specific guide surfaces that require smooth movement and stable guidance, rather than using it for the entire guide means structure. The bulk structural components can be made from more economical materials, thereby achieving the required guidance stability and smooth operation while controlling manufacturing costs through selective material application.

Inventive Principle:
Principle #3Local quality

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 user comfort by preventing unwanted yielding and noise during height adjustment, while maintaining stability and compactness, suitable for recliner chairs with limited installation space.

Implementation Method 1

The height adjustment means comprises a rigidly locking gas pressure spring

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

The guide means is designed to guide the displaceable part of the height adjustment means during such a displacement

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3001932B1Device for adjusting the height of a seat of an item of seating furniture
Publication Date: 2018.04.25 INNOTEC MOTION GMBH
  • EP3001932B1 patent drawingFigure 1~2

AI summary

The invention relates to a device (100) for adjusting the height of a seat surface of a piece of seating furniture, comprising a housing (105), a height adjustment means (101) and a guide means (106), wherein at least a part (102) of the height adjustment means (101) is displaceable relative to the housing (105), and wherein the guide means (106) is configured to guide the displaceable part (102) of the height adjustment means (101) during such a displacement, wherein the height adjustment means (101) comprises a rigidly blocking gas spring.