Active-Dynamic Chair Joint with Force-Dependent Elastic Elements
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Solution Overview
Problem
Existing active-dynamic chairs lack a pendulum joint that is both safe for varied user movements and inexpensive to manufacture, while also ensuring a long service life.
Innovation Solution
A joint arrangement featuring a hollow cylindrical receiving cylinder with deformable elastic elements that change shape and position within a bearing gap between conically tapering outer and inner wall portions, allowing force-dependent actuation and increased compression with reduced clearance, enhancing the chair's mobility and ergonomic support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid connection is used for the interface between base and intermediate portion, then structural stability is improved, but user safety and comfort during movement deteriorate
Solution Approach 1:
The patent applies the dynamics principle by replacing the rigid connection with a dynamic pendulum joint that allows controlled movement. The receiving cylinder can rotate and tilt within the joint shell, enabling the chair to adapt to user movements while maintaining stability through the pendulum mechanism's natural return to equilibrium position.
Solution Approach 2:
The patent changes the connection parameter from rigid to flexible by introducing a bearing gap between the receiving cylinder and joint shell. This gap allows angular and rotational movements, transforming the structural parameter to enable both stability and user safety during dynamic use.
2Reliability
If complex joint mechanisms are used to enable varied movements, then user safety and comfort are improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent segments the joint mechanism into simple, discrete components: receiving cylinder, joint shell, elastic elements, and bearing surfaces. This segmentation allows each component to be manufactured independently using standard processes, reducing overall complexity while enabling varied movements through their coordinated interaction.
Solution Approach 2:
The pendulum joint is designed to be self-regulating through the elastic elements that automatically provide restoring force. The mechanism serves itself by using the user's weight and movement to activate the elastic elements, which then automatically return the chair to its neutral position without requiring additional control systems.
3Reliability
If deformable elastic elements are used in the bearing gap, then user safety and movement control are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the bearing gap from a fixed precision dimension to a variable parameter that adapts during operation. The elastic elements allow the gap to change dynamically based on user weight and movement, reducing the need for tight manufacturing tolerances while maintaining movement control.
Solution Approach 2:
The patent effectively creates a compliant, porous-like interface through the elastic elements in the bearing gap. This compliant structure accommodates manufacturing variations by deformable contact rather than rigid precision fitting, reducing manufacturing precision requirements while maintaining reliable movement control.
4Reliability
If the receiving cylinder is actuated with reduced clearance, then force-dependent movement control is improved, but the compression force required increases
Solution Approach 1:
The patent applies dynamics by creating a force-dependent movement control system where the compression force varies dynamically with user weight and movement intensity. Lighter users experience softer, easier movement while heavier users naturally generate more compression force, providing appropriate resistance for each user without requiring adjustable mechanisms.
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 safe and varied seat movements within a defined range while maintaining cost-effectiveness and longevity, as the elastic elements compress and deform with increasing force, adjusting the chair's deflection based on user weight.
Implementation Method 1
deformable elastic elements that are arranged so as to be variable in shape and position in a bearing gap between an outer wall portion of the receiving cylinder and an inner wall portion of the joint shell and the receiving cylinder can be actuated in a force-dependent manner, which changes the shape and/or position of the elastic elements
Implementation Method 2
between a conically tapering outer wall portion of the receiving cylinder and a conically tapering inner wall portion of the joint shell and the receiving cylinder can be actuated in a force-dependent manner in a cylinder axis direction, which changes the shape and/or position of the elastic elements as a result of a reduction in the clearance of the bearing gap
Data Source
AI summary
Joint arrangement (10) has a hollow cylindrical receiving cylinder (20) that extends in a cylinder axis direction (Z) and receives one end of a chair column (30) of an active-dynamic wobble chair, the latter movably mounted in a substantially hollow cylindrical outer joint shell (40) composed of joint shell segments (45). Movable mounting of receiving cylinder (20) is achieved by deformable elastic elements (50) arranged to be variable in shape and position in a bearing gap (60) between an outer wall portion (21, 22) of the receiving cylinder (20) and an inner wall portion (41, 42) of the joint shell (40). Receiving cylinder (20) is actuated in a force-dependent manner, whereby shape and/or position of the elastic elements (50) change as viewed in a radial direction (Rs) from changing, preferably reducing, clearance of the bearing gap (60) when the receiving cylinder (20) is actuated in a cylinder axis direction (Z).