Chair Release Element with Weight-Activated Locking for Stability

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Solution Overview

Problem

Existing chairs cannot be designed as combined sitting and standing chairs without slipping or rolling away, as they lack a mechanism to prevent unintentional movement when used as a standing aid.

Innovation Solution

Incorporating a release element with a Bowden cable system that activates functional elements such as rollers or locking devices, allowing the chair to transition from a passive to an active position based on weight, preventing accidental slipping or rolling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the chair is designed with castors for easy movement, then ease of operation is improved, but stability deteriorates when used as a standing chair

Engineering Contradiction:
Improveease of movementVSAvoidstability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The chair incorporates a dynamic locking mechanism that automatically transitions the castors between locked and unlocked states based on detected weight. When weight is detected (user sitting or standing), the mechanism locks the castors to prevent rolling. When no weight is detected, the castors are unlocked for easy movement. This dynamic adaptation resolves the contradiction between ease of movement and stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism is designed to automatically activate based on weight detection without requiring manual intervention. The system self-regulates the castor lock state according to whether the chair is being used or stored, eliminating the need for user action to switch between movement and stability modes.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the chair is designed as a combined sitting and standing chair, then adaptability is improved, but reliability deteriorates due to unintentional slipping or rolling

Engineering Contradiction:
Improvecombined sitting and standing functionVSAvoidprevention of unintentional movement
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking mechanism preemptively prevents unintentional movement by automatically locking the castors when weight is detected on the chair. This preliminary action occurs before any slipping or rolling can happen, ensuring reliability while maintaining the chair's dual functionality for both sitting and standing use.

Inventive Principle:
Principle #9Preliminary anti-action

3Stability of the object's composition

If a release element with Bowden cable is added to activate functional elements, then stability is improved, but device complexity increases

Engineering Contradiction:
ImprovestabilityVSAvoidmechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The Bowden cable acts as an intermediary transmission element that connects the release element to the locking mechanism. This allows the locking function to be activated remotely and smoothly, distributing the mechanical action through the cable system rather than requiring direct connection, thereby managing complexity while achieving reliable stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the chair to be securely used as both a sitting and standing aid without unintended movement, ensuring stability and ease of movement when needed.

Implementation Method 1

At least one Bowden cable acts on at least one functional element on the release element

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the adjustment from its rest position to its activation position takes place by means of the weight of an object acting on the release element

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

at least one roller which is rotatably mounted on the roller body via a roller axis

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3672451B1Chair having a release element
Publication Date: 2020.12.02 SEDUS STOLL
  • EP3672451B1 patent drawingFigure 1
  • EP3672451B1 patent drawingFigure 2
  • EP3672451B1 patent drawingFigure 3

AI summary

The invention relates to a chair comprising a supporting frame (2), a supporting unit (4), which is arranged on the supporting frame (2), a seat element (6) and a backrest element (8), which are each supported by the supporting unit (4). The chair also comprises a first release element, which is arranged between the supporting unit (4) and the seat element (6) and on which at least one Bowden cable (34, 35, 36, 37) of at least one functional element acts, which release element is adjustable between a rest position, in which the release element does not act on the at least one Bowden cable (34, 35, 37, 37), and an activation position, in which the release element acts on the at least one Bowden cable (34, 35, 36, 37) and thus activates the functional element.The release element is preloaded into the rest position thereof by means of a release element loading means, wherein the first release element is formed in such a way that the displacement from the rest position of the first release element into the activation position thereof is carried out by means of the weight of an object acting on the first release element.