Chair Back Swivel Mechanism With Centering Springs and Lock
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Solution Overview
Problem
Existing chair backrest mechanisms do not effectively allow for independent swiveling of the backrest relative to the seat, limiting user adjustability and comfort.
Innovation Solution
A backrest swivel mechanism that includes a first boss and a second boss, positioned within a slot to define a path of rotation about a vertical axis, allowing the backrest to swivel between defined positions while being biased to a centered position by springs, with a locking device for control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backrest is rigidly connected to the seat, then structural integrity is maintained, but user adjustability and comfort are limited
Solution Approach 1:
The backrest connection mechanism is segmented into multiple independent components: a first boss for vertical axis rotation, a second boss within an arcuate slot for lateral movement, and spring elements. This segmentation allows the backrest to achieve complex adjustability (swiveling and reclining) through simple, modular components rather than a single complex joint.
Solution Approach 2:
Spring elements are introduced as intermediary components between the backrest and seat connection points. These springs mediate the force transmission, providing both structural support and adjustable positioning capabilities, thereby enhancing adaptability while maintaining manageable complexity.
2Ease of operation
If the backrest is allowed to swivel freely without constraints, then user comfort is improved, but structural stability is compromised
Solution Approach 1:
The connection mechanism transitions from a static rigid connection to a dynamic system where the backrest can swivel and recline within controlled ranges. The arcuate slot and spring elements enable smooth motion while the geometric constraints of the slot boundaries provide natural stopping points, ensuring both ease of operation and positioning stability.
Solution Approach 2:
The mechanism changes the operational parameters of the backrest connection by introducing rotational degrees of freedom around a vertical axis and reclining motion along an arcuate path. These parameter changes enable smooth swiveling and reclining while the physical constraints of the boss-slot geometry maintain stable positioning within defined ranges.
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 smooth and adjustable swiveling of the backrest within specified ranges, enhancing user comfort and adjustability without compromising structural integrity.
Implementation Method 1
The backrest swivel mechanism can also comprise a first spring having a first end attached to a connection member of the backrest swivel mechanism and a second end attached to the bottom portion of the backrest and a second spring having a first end attached to the connection member and a second end attached to the bottom portion of the backrest.
Data Source
AI summary
A chair includes a backrest swivel mechanism that is configured to permit the backrest to swivel about a vertical axis about a preselected range of motion. The backrest may be configured to swivel, or rotate, about a vertical axis that is defined by an element located adjacent a rearward central location that is below the seat of the chair and adjacent a rear of the chair. A lock mechanism can be selectively engaged to lock and unlock the swiveling mechanism so that when in the locked state, the backrest cannot swivel and when in the unlocked state, the backrest can swivel. In some embodiments, the range of swiveling motion may be with a predefined range, such as +/−10° or +/−20° of rotation relative to a central position of the backrest.