Concentric Ring Armrest Hinge for Synchronized Backrest Movement
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Solution Overview
Problem
Existing chair designs with movable backrests and armrests either lack the ability for the armrest to follow the backrest's movement or require the user to release the armrest during adjustments, compromising user comfort.
Innovation Solution
A chair design featuring concentric inner and outer rings forming the armrest, where the outer ring is secured to the backrest and the inner ring to the seat, with a bearing allowing synchronized movement between the two, enabling the armrest to follow the backrest's adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backrest is made movable relative to the seat using a sliding arrangement between the armrest and legs, then the backrest can be adjusted, but the armrest cannot follow the movement of the backrest
Solution Approach 1:
The armrest is divided into two separately movable parts: a first part connected to the seat and a second part connected to the backrest. This segmentation allows each part to move independently, enabling the second part to follow the backrest's movement while the first part remains relatively stable, thus resolving the contradiction between backrest adjustability and armrest continuity.
Solution Approach 2:
The armrest transitions from a static or single-movement component to a dynamic system with two independently movable parts. This allows the armrest to adapt its configuration in real-time, following the backrest's movement when needed while maintaining stability when the backrest is stationary, thereby achieving both adjustability and operational comfort.
2Device complexity
If the armrest is fixed to either the seat or the backrest, then the structure is simple, but the armrest cannot provide continuous support during backrest adjustment
Solution Approach 1:
The armrest is segmented into two parts with different connection points: one part to the seat and another to the backrest. This segmentation creates a simple yet effective mechanism where each part can move independently, providing continuous support during adjustment without requiring complex multi-component systems.
Solution Approach 2:
The first armrest part acts as an intermediary between the seat and the second armrest part. It transfers and coordinates movements between the stationary seat and the moving backrest, enabling smooth transitions and continuous support while maintaining structural simplicity.
3Adaptability or versatility
If the backrest and seat are secured by a hinge with two movable parts, then the armrest can potentially follow movement, but the armrest will not automatically follow the backrest's movement
Solution Approach 1:
The armrest is divided into two parts with specific connection assignments: the first part to the seat and the second part to the backrest. This segmentation creates a natural mechanical linkage where the second part inherently follows the backrest's movement due to its direct connection, achieving automatic synchronization without complex control mechanisms.
Solution Approach 2:
The armrest system merges the functionality of two separate armrest configurations into one unified structure. By combining elements connected to both the seat and backrest, the system achieves both stability and movement-following capability in a single integrated design.
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
Enhances user comfort by allowing the armrest to move in tandem with the backrest without the need to release it, providing continuous support during adjustments.
Implementation Method 1
a bearing, such as a ball bearing, is mounted between the inner ring and the outer ring
Data Source
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AI summary
A chair (1), in particular a dentist's chair, which has a seat (3) and a backrest (2) which are connected with each other by means of a hinge (6) consisting of two movable parts in the form of an inner ring (8) and an outer ring (7) disposed concentrically therewith. The inner ring (8) is secured to the seat (3), while the outer ring (7) is secured to the seat (3). The outer side of the inner ring (8) engages the inner side of the outer ring (7), a ball bearing (11 , 12) being mounted between the inner ring (8) and the outer ring (7). The invention provides a dentist's chair where the armrest follows the movement of a user's back.