Reclining Seat-Back Linkage for Stable Leg Space
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Solution Overview
Problem
Traditional reclining chairs and sofas face issues where the seat slides forward and upward when the back is reclined, reducing leg space and causing instability, or the back moves independently, leading to an uncomfortable sliding sensation.
Innovation Solution
A seating furniture design featuring a rotatable coupling between the seat and backrest devices, supported by link arms and a base, with a lockable control device that allows simultaneous adjustment of the back and seat angles without the seat moving forward, utilizing a gas spring mechanism for balanced movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the back is reclined in traditional seating furniture, then the backrest angle is adjusted, but the seat slides forward and upward reducing leg space
Solution Approach 1:
The invention divides the traditional unified seat-back assembly into separate movable components: the seat device can move independently on the base, while the backrest device moves relative to the seat through the first rotatable coupling. This segmentation allows the backrest to recline without necessarily moving the seat forward, preserving leg space.
Solution Approach 2:
The invention introduces dynamic movement capabilities through multiple rotatable couplings - the first rotatable coupling allows the backrest to move relative to the seat, while the second rotatable coupling allows the seat to move relative to the base. This dynamic system enables independent control of seat and backrest positions to maintain leg space during reclining.
2Adaptability or versatility
If the back moves independently while the seat remains stationary, then the backrest angle is adjusted, but the user experiences a sliding sensation
Solution Approach 1:
The invention merges the movement of the seat and backrest through coordinated action. The control device can simultaneously actuate both the first rotatable coupling (backrest relative to seat) and the second rotatable coupling (seat relative to base), ensuring they move together as a unified system to eliminate the sliding sensation.
Solution Approach 2:
The gas spring mechanism provides force feedback that balances the weight and forces during reclining. The gas spring is configured to work with the link arm and rotatable couplings to provide smooth, controlled movement that maintains user comfort throughout the reclining range.
3Adaptability or versatility
If the seat moves forward and up at the rear end, then the backrest angle is adjusted, but the overall stability and balance are reduced
Solution Approach 1:
The gas spring acts as a counterweight mechanism, providing upward force to balance the downward force of the user's body weight during reclining. The gas spring is positioned and configured to work with the link arm and rotatable couplings to maintain balance and stability throughout the movement range.
Solution Approach 2:
The invention creates a balanced system where the gas spring, link arm, and rotatable couplings work together to maintain equipotential conditions during reclining. The gravitational forces and gas spring forces are balanced to provide smooth, controlled movement without sudden shifts or instability.
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
This design maintains balance and stability by allowing the back and seat to recline together, increasing the seat angle without reducing leg space, and is lightweight, safe, and aesthetically flexible with concealed mechanisms.
Implementation Method 1
The mutual movement of the back and the seat are controlled by a lever which opens or closes a gas spring that balances weight and forces in a completely new way.
Data Source
AI summary
A seating furniture includes a seat device and a backrest device connected via at least one first rotatable coupling in respective coupling portions (P) of the backrest device and at rear portion (B) of the seat device. A base supports the seat device and the backrest device. The backrest device comprises a portion extending in a direction towards the base and past the first rotatable coupling, and the portion is rotatably coupled to and supported on the base via at least one respective link arm. The seat device is rotatably coupled to and supported on the base via a second rotatable coupling attached closer to front end (F) of the seat device than the first rotatable coupling. A lockable control device controls the movements between the backrest device and the seat device. The construction is well-balanced, and low forces are required to adjust the chair in all positions.