Seating furniture
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Solution Overview
Problem
Existing rocking mechanisms for seating furniture are complex and heavy, with high sliding resistance and potential for noise and wear, limiting ergonomic and comfortable tilting capabilities.
Innovation Solution
A simplified rocking mechanism with a gas spring actuated by a user lever, featuring a convexly curved lower bearing block and a concavely curved upper bearing block with matching radii, an intermediate member for reduced sliding resistance, and an elastic element for smooth and quiet tilting, housed to protect components and prevent impact noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional rocking mechanisms with multiple conicities are used to enable tilting in multiple directions, then the tilting functionality is improved, but the device complexity and weight increase
Solution Approach 1:
The patent employs a spherical bearing surface with a single radius of curvature that enables tilting in multiple directions. The bearing block has a spherical bearing surface that contacts a corresponding spherical surface on the seat, allowing rotation and tilting in all directions around the spherical contact point, eliminating the need for multiple conic surfaces while achieving multi-directional tilting functionality
Solution Approach 2:
The single spherical bearing surface serves multiple functions simultaneously: it enables forward/backward tilting, right/left tilting, and circumferential rotation, making one structural element perform what previously required multiple specialized surfaces, thereby simplifying the overall mechanism while maintaining versatility
2Strength
If conventional bearing surfaces with high sliding resistance are used, then the structural strength is maintained, but the wear and noise increase reducing service life
Solution Approach 1:
The patent introduces an intermediate element made of PTFE (polytetrafluoroethylene) material positioned between the lower and upper bearing surfaces. This intermediate layer acts as a mediator that reduces sliding resistance and friction between the bearing surfaces, thereby reducing wear and noise while maintaining the structural strength of the metal bearing blocks. The PTFE layer has self-lubricating properties that enhance reliability and service life
3Ease of operation
If the bearing surfaces are made to match with precise radii of curvature, then the smoothness of tilting is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The PTFE intermediate element serves as a compliant layer that compensates for minor variations in the radii of curvature of the bearing surfaces. Its material flexibility and self-lubricating properties allow it to conform to the spherical surfaces, ensuring smooth tilting movement even with reasonable manufacturing tolerances, thereby reducing the stringency of precision requirements while maintaining operational smoothness
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 enables easy, ergonomic, and comfortable tilting with reduced weight and increased service life, minimizing noise and wear, while allowing continuous or discrete inclination in multiple directions.
Implementation Method 1
a base frame having a support column with a gas spring, wherein the gas spring can be actuated by a user by means of an operating lever
Implementation Method 2
the lower bearing block has a convexly curved lower bearing surface on its upper side facing the upper bearing block and the upper bearing block has a concavely curved upper bearing surface on its lower side facing the lower bearing block, wherein the lower bearing surface of the lower bearing block and the upper bearing surface of the upper bearing block have substantially the same radii of curvature and wherein the upper bearing block is displaceable along the upper bearing surface relative to the lower bearing block
Implementation Method 3
an intermediate element between the lower bearing surface and the upper bearing surface, which is placed on the lower bearing surface and has a reduced sliding resistance on its upper side facing the upper bearing surface
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an item of seating furniture (10) having a seat (12) with a seat surface (12a), a foot rest (14) and a rocker mechanism (24). The rocker mechanism (24) is arranged between the foot rest (14) and the seat (12) and designed in such a way that it permits an inclination of the seat surface (12a) of the seat (12) in relation to the horizontal. In addition, the rocker mechanism (24) has a lower bearing block (26) that is secured to the foot rest (14), and an upper bearing block (30) that is securely connected to the seat (12). The lower bearing block (26) has a convexly curved lower bearing surface (28) on its upper side facing the upper bearing block, and the upper bearing block (30) has a concavely curved upper bearing surface (32) on its lower side facing the lower bearing block. The lower and the upper bearing surfaces (28, 32) have substantially corresponding radii of curvature, such that the upper bearing block (30) can be moved relative to the lower bearing block (26) along the upper bearing surface (32).