Passive Exoskeleton Lever Arm for Sit-to-Stand Weight Transfer
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Solution Overview
Problem
Conventional assistive exoskeleton devices are often large, uncomfortable, and expensive, and do not provide a passive solution for individuals with weak or damaged muscles to safely lift and lower themselves from sitting to standing positions, lacking the ability to transfer weight effectively.
Innovation Solution
A wearable passive exoskeleton device with a leg exoskeleton frame, a rotatable lever arm, and a ratcheting pivot mechanism that allows users to transfer their weight to the ground using upper body strength, reducing strain on weaker lower body muscles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional powered or active assistive exoskeleton devices are used, then users can receive assistance in lifting and lowering themselves, but the devices become large, uncomfortable, and expensive to manufacture
Solution Approach 1:
The patent replaces complex powered mechanical systems with a passive mechanical system using a ratcheting pivot mechanism. The ratcheting pivot allows motion in one direction (assisting the lifting motion) while preventing reverse motion, providing assistive capability through pure mechanical means without motors or power sources, thereby reducing device complexity, size, and cost
Solution Approach 2:
The patent extracts the power source and active control systems from the exoskeleton, retaining only the essential passive mechanical components (frame, lever arm, and ratcheting pivot). This extraction eliminates the need for batteries, motors, and control electronics, directly addressing the issues of device size, comfort, and manufacturing cost while maintaining assistive functionality
2Ease of operation
If conventional assistive exoskeleton devices are used, then users can receive some support, but they cannot instantly transfer their weight to assist them in rising from the floor or from a chair/bed
Solution Approach 1:
The patent employs a dynamic lever arm that can rotate between a stowed position and a deployed position. The lever arm is designed to be deployable, allowing users to instantly transfer their weight by pushing or pulling on the lever arm when needed. This dynamic configuration provides on-demand assistive effectiveness while maintaining ease of operation through simple user-initiated weight transfer
Solution Approach 2:
The lever arm serves as an intermediary mechanical element between the user's body and the ground. By pushing or pulling on the lever arm, users can instantly transfer their weight through this intermediary to the ground, enabling rapid transitions from sitting/lying positions to standing without requiring direct leg muscle effort
3Adaptability or versatility
If users rely on nearby support surfaces to pull themselves up or push against, then they can transition from lowered to standing position, but they cannot move freely without external supports
Solution Approach 1:
The patent creates a self-contained exoskeleton system that provides assistive functionality regardless of external support availability. The device attaches to the user's leg and foot, creating a portable assistance system that works in any environment. The ratcheting pivot mechanism universally assists both lifting (sit-to-stand) and lowering (stand-to-sit) motions, providing mobility independence without dependence on external supports
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 individuals to move between sitting and standing positions effortlessly, reducing muscle strain and injury risk, while being affordable and easily attachable to any shoe, enhancing mobility and independence.
Implementation Method 1
a ratcheting pivot whereby the lever arm is rotatably mounted to the leg exoskeleton frame, wherein the lever arm is configured to rotate with respect to the leg exoskeleton frame in a first rotational direction from the stowed position to the deployed position
Implementation Method 2
a lever arm rotatably coupled to the leg exoskeleton frame so as to provide a handle for the user to move between a sitting position and a standing position
Data Source
AI summary
A wearable passive exoskeleton device for sit-to-stand and/or stand-to-sit transfer includes a leg exoskeleton frame configured to be worn at a user's leg and a lever arm rotatably coupled to the leg exoskeleton frame so as to provide a handle for the user to move between a sitting position and a standing position (or between a kneeling position and a standing position). The lever arm is rotatable with respect to the leg exoskeleton frame between a stowed position and a deployed position. The lever arm may be a unidirectional lever arm configured to rotate only in a first rotational direction with respect to the leg exoskeleton frame such that a pushing or pulling force exerted in a second rotational direction transmits an assisting force to the user to assist in a sit-to-stand and/or stand-to-sit movement.