Chair Spring Force Adjustment Using Tensile-Only Actuating Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chair mechanisms for adjusting spring force are complex and prone to jerking issues due to the engagement of the spring guide with locking recesses, requiring a simpler and smoother adjustment mechanism.
Innovation Solution
Incorporating an actuating element that exclusively transmits tensile forces, such as a chain or rope, to adjust the spring's position on the bearing surface, allowing for a more straightforward and precise control of the spring force without the complexity of planetary gears or compressive force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a planetary gear mechanism with locking recesses and locking pins is used to adjust spring force, then the spring force can be adjusted in discrete positions, but the mechanism becomes structurally complex and produces jerking motions during adjustment
Solution Approach 1:
The patent extracts the locking mechanism from the adjusting system by using a chain that engages with teeth on the adjusting wheel, eliminating the need for complex planetary gears and locking recesses. The chain naturally maintains engagement through its flexible tension-based connection, providing continuous adjustment without discrete locking positions.
Solution Approach 2:
Instead of using a rigid gear mechanism that locks at discrete positions, the patent inverts the approach by using a flexible chain that maintains continuous contact through tension. This reverses the traditional gear-locking concept to achieve smooth, continuous adjustment without jerking motions.
2Ease of operation
If a planetary gear mechanism is used to transmit adjusting forces, then the spring force can be adjusted, but the mechanism becomes prone to jerking issues and requires complex components
Solution Approach 1:
The patent employs a flexible chain instead of rigid gear components. The chain's flexibility allows it to conform to the adjusting wheel's circumference and maintain continuous contact through tension, eliminating the jerking motions inherent in rigid gear mechanisms while preserving full adjustability.
Solution Approach 2:
The chain-based adjusting mechanism dynamically adapts to the adjusting wheel's rotation, maintaining continuous engagement through tension rather than relying on discrete locking positions. This dynamic engagement ensures smooth operation and eliminates the jerking issues associated with static gear-locking mechanisms.
3Manufacturing precision
If locking recesses and locking pins are used to position the spring, then discrete adjustment positions are achieved, but the mechanism produces jerking motions when loaded
Solution Approach 1:
The patent removes the locking recesses and locking pins from the system, replacing them with a chain that engages teeth on the adjusting wheel. This extraction eliminates the source of jerking motions while maintaining precise spring positioning through the chain's tension-based engagement.
Solution Approach 2:
The chain acts as an intermediary between the adjusting wheel and the spring, providing continuous contact and force transmission. This intermediary mechanism eliminates the direct engagement of locking pins with recesses that causes jerking, while still achieving precise positioning through the chain's flexible connection.
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 solution provides a structurally less complex mechanism for adjusting spring force, eliminating jerking issues and enabling precise control, resulting in a smoother and more reliable chair adjustment system.
Implementation Method 1
a spring (4) pressing the seat (2) into a basic position of the chair
Implementation Method 2
an adjusting element (6), which exclusively transmits tensile forces, is provided for determining the position of one end of the spring (4) on the bearing surface (5.1)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a chair comprising a chair base (1) on which a seat and a backrest connected to the seat via a synchronizing mechanism are movably mounted, wherein a spring (4), that presses against the seat when the chair is in the base position and an abutment (5) which is rotatably mounted on the chair base (1), are provided. The abutment (5) cooperates with the seat and comprises a bearing surface (5.1) on which one end of the spring (4) can be positioned in different positions in order for adjusting an active spring force. According to the invention, an adjusting element (6) transmitting exclusively traction forces for determining the position of one end of the spring (4) on the bearing surface (5.1) is provided.