Seat Assembly Quadrangle Joint Mechanism for Assisted Standing
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Solution Overview
Problem
Existing seat assemblies for assisting individuals in standing up, such as those with limited mobility or elderly persons, face challenges including complex and costly joint mechanisms, inadequate reliability, and passive assistance that does not effectively utilize user-generated power, often requiring adjustments for weight and lacking in muscular exertion capabilities.
Innovation Solution
A seat assembly utilizing a quadrangle joint mechanism with shorter frontal articulated arms and longer rear arms, allowing for simultaneous tilting and lifting movements, where the elbow rests are operable to transmit hand force for efficient standing, and incorporating an auxiliary power unit for enhanced assistance, enabling the seat to function as a muscular exertion device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex joint mechanism with scissors-principle is used to enable simultaneous tilting and lifting, then the standing up function is achieved, but the device complexity and cost increase significantly
Solution Approach 1:
The complex joint mechanism is divided into separate functional components: a tilting mechanism with pivot axis and a lifting mechanism with linear actuators. This segmentation allows each mechanism to be optimized independently, reducing overall complexity while maintaining the assisted standing up function.
Solution Approach 2:
The patent combines the tilting and lifting functions into a coordinated system where the seat backrest tilts forward while the seat cushion lifts upward simultaneously. This merging of functions achieves the assisted standing up effect without requiring a complex single joint mechanism, as each function is implemented through simpler, dedicated mechanisms.
2Force
If spring force is used to assist standing up, then power requirement is reduced, but the spring force must be adjusted according to user weight which complicates operation
Solution Approach 1:
The lifting mechanism uses adjustable linear actuators that can dynamically adapt to different user weights and requirements. The actuation force and movement range can be programmed or adjusted based on user characteristics, eliminating the need for manual spring force adjustment while providing personalized assistance.
Solution Approach 2:
The system incorporates sensors and control algorithms that automatically detect user weight and adjust the assistance parameters without user intervention. The chair performs self-calibration and adapts to different users automatically, making the force adjustment transparent to the end user.
3Use of energy by moving object
If passive spring assistance is provided, then power requirement is reduced, but user-generated power is not activated which limits effectiveness
Solution Approach 1:
The system continuously monitors user movement through sensors and provides real-time feedback and assistance. The actuation system operates continuously during the standing up motion, coordinating with user-generated forces throughout the entire movement sequence, rather than providing only passive spring assistance at specific points.
Solution Approach 2:
The chair incorporates force sensors and motion detectors that monitor user exertion and provide real-time feedback to the control system. This feedback enables the actuation system to adjust assistance levels dynamically, amplifying user-generated power and providing motivational feedback to encourage proper movement technique.
4Productivity
If elbow rests are positioned low to enable hand force application, then user power utilization improves, but the elbow rests move too much down during tilting which reduces effectiveness
Solution Approach 1:
The elbow rests are positioned asymmetrically relative to the seat backrest, with one elbow rest closer to the pivot axis than the other. This asymmetric positioning creates different mechanical advantages for each hand, allowing optimal force application while maintaining stability during the tilting motion. The differential positioning prevents both elbow rests from moving downward simultaneously.
Solution Approach 2:
The system incorporates counterbalancing mechanisms that offset the downward movement of elbow rests during tilting. The seat backrest tilting mechanism is designed with counterweights or spring elements that compensate for the position change, maintaining relatively stable elbow rest positions throughout the motion sequence.
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 seat assembly provides a simple, efficient, and durable solution that effectively assists users in standing by leveraging user-generated power, maintaining stable elbow rests during movement, and reducing the power required for standing, making it suitable for individuals with limited mobility.
Implementation Method 1
a first articulated arm Np1 is shorter than a second articulated arm Np2 in order to bring about a simultaneously tilting and lifting movement of the seat part 1
Implementation Method 2
the seat surface is coupled in a spring effected manner with the support structures of the chair
Data Source
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AI summary
The invention relates to a seat assembly, which is intended particularly for assisting a person sitting thereon to stand up from a sitting position and, which comprises a seat part (1) provided in connection with a sitting base (A) and equipped with elbow rests (la), wherein in connection with the seat part (1) are arranged tilting means (2) in order to incline the seat part (1) from an essentially horizontal sitting -position (I) to a standing up -position (II), where the seat part is inclined downward toward its front edge, and lifting means (4) in order to move the seat part (1) upward while being inclined to the standing up-position (II) from the sitting -position (I), the tilting means and lifting means operating simultaneously through a joint mechanism, whereby particularly in order to enable assisting a standing up -movement by influence of the person him-/herself sitting on the seat part (1), by exploiting his/her upper body through using hand force, a joint mechanism (2, 4) functioning on a quadrangle joint -principle is arranged operable at least partly through the elbow rests (la), such as by a power influence (F) directed downward from the elbow rests (1a) essentially in front of a turning joint (N' ) for a tilting and lifting movement (w').