Standing Chair Kinematics for Vertical Sit-Stand Comfort
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Solution Overview
Problem
Standing chairs for individuals with disabilities often cause discomfort due to unnatural body movements during verticalization, and they do not provide the same height as able-bodied individuals, leading to physiological issues and social disadvantages.
Innovation Solution
A standing chair with a seat movement mechanism and a horizontally movable footrest, featuring coordinated kinematics that maintain the user's center of gravity along a vertical axis, ensuring smooth transitions between seated and standing positions while preserving ergonomic comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the seat is moved vertically from seated to standing position, then the user's height is improved and physiological benefits are achieved, but the body movement becomes unnatural and uncomfortable
Solution Approach 1:
The footrest is designed to move dynamically in coordination with the seat movement, transitioning from a stationary component to an actively controlled element that adapts its position based on the seat's vertical displacement, thereby maintaining natural body alignment throughout the transition
Solution Approach 2:
The system changes the positional parameters of both the seat and footrest simultaneously, with the footrest's horizontal position being adjusted as a function of the seat's vertical position, creating a coordinated kinematic relationship that preserves ergonomic body angles
2Device complexity
If the footrest is fixed relative to the seat, then the structure is simple, but the user's center of gravity moves unnaturally during verticalization
Solution Approach 1:
The footrest is separated from the seat structure, becoming an independent component with its own movement mechanism, allowing it to be positioned independently to maintain proper body alignment while the seat moves vertically
Solution Approach 2:
A control system acts as an intermediary between the seat movement mechanism and the footrest, coordinating their movements to ensure the user's center of gravity follows a natural vertical path during transitions
Data Source
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AI summary
A standing chair (10) for a user (20), preferably with a disability, the chair comprising a seat (12), a backrest (14), and a footrest (16). A mechanism for moving the seat (15) is adapted to move the seat between a first position corresponding to a "seated" position and a second position corresponding to a "sit-stand" position. The footrest is mobile along a horizontal axis H while remaining mechanically independent of the seat's movement. The coordinated kinematics of the seat and footrest are such that the user's center of gravity moves along a line following a vertical axis V.