Pivoting Footrest Linkage With Variable-Length Support Arms
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Solution Overview
Problem
Existing seating furniture designs for armchairs or sofas with pivoting foot parts are structurally complex and require significant effort for reliable and comfortable adjustment, making it difficult to adapt the foot part adjustment to different user requirements or furniture configurations.
Innovation Solution
A control lever fixed to pivot about at least two mutually perpendicular axes, connected to the chassis and the foot part via a telescoping device, allows for flexible length adjustment of the support arm structure, enabling simpler and more adaptable foot part adjustment by using a drive lever, coupling lever, and output lever to transmit adjustment movements effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the support arm structure is made longer to allow the foot part to position far in front of the seat for user comfort, then the foot part can be positioned further forward in use position, but the foot part may collide with the ground when pivoted to non-use position and the structure becomes more complex
Solution Approach 1:
The support arm structure is designed with variable length capability through a telescopic device, allowing it to dynamically adjust between extended and retracted positions. This enables the structure to be long when the foot part is in the use position for comfort, and short when in the non-use position to avoid ground collision, thus resolving the contradiction between positioning comfort and structural complexity.
2Object-affected harmful factors
If the support arm structure is made variable in length to avoid ground collision in non-use position, then the foot part can clear the ground, but the adjustment mechanism becomes structurally complex and difficult to adapt to different users
Solution Approach 1:
A control lever is introduced as an intermediary mechanism that connects the foot part to the support arm structure. This control lever simplifies the adjustment process by providing a direct mechanical linkage that automatically adjusts the telescopic device's length, avoiding the need for complex motorized or electronic adjustment systems while still achieving ground collision avoidance.
Solution Approach 2:
The telescopic device within the support arm structure enables dynamic length adjustment, allowing the structure to adapt its length based on the foot part's position. This dynamic capability ensures the foot part can clear the ground in non-use position while maintaining a relatively simple overall mechanism through passive mechanical adjustment.
3Adaptability or versatility
If a control fitting is added to determine the support arm structure length, then the foot part adjustment can be controlled, but the overall structure becomes more complex requiring multiple levers and connections
Solution Approach 1:
The control lever is designed to perform multiple functions: it directly controls the telescopic device's extension and retraction, provides structural support for the foot part, and enables adjustment to different positions. By consolidating these functions into a single component, the design achieves high adaptability without proportionally increasing structural complexity.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A seating furniture (1), in particular an armchair or sofa, is shown and described, comprising a chassis (3) and a foot section (6) which can be pivoted relative to the chassis (3) from a lower non-use position to an upper use position, wherein the foot section (6) is held on the chassis (3) by at least one pivotable support arm structure (7), wherein the foot section (6) is connected to the chassis (3) by at least one pivotable control fitting (10), wherein the length of the support arm structure (7) between the chassis (3) and the foot section (6) changes when the foot section (6) pivots from the non-use position to the use position and back, wherein the length of the support arm structure (7) between the chassis (3) and the foot section (6) is shorter in the non-use position of the foot section (6) than in the use position of the foot section (6), and wherein the position of the control fitting (10) determines the length of the support arm structure (7) between the chassis (3) and the foot section (6).In order to make the footrest adjustment easier to provide and adapt, it is proposed that the control fitting (10) has a control lever (11) which is pivotable about at least two axes perpendicular to each other and fixed to the chassis (3).