Four-Bar Lifting Mechanism for Natural User Motion
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Solution Overview
Problem
Conventional devices for lifting and lowering individuals with limited leg strength or mobility are either cumbersome, require unnatural lifting motions, or lack stability, often necessitating the use of external power sources and failing to facilitate natural movement paths.
Innovation Solution
A four-bar apparatus with an actuator and interconnected lifting mechanism, including a crank, coupler, rocker, and frame, which replicates natural standing motions by lifting via a J-shape or S-shape path from either the shoulder or hip, providing stability and allowing the user to transition between seated and standing positions while supporting weight at the buttocks or armpit region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional devices use compressed air cylinders or gas springs for lifting, then lifting power is provided, but the device becomes cumbersome and requires transport and refilling of power sources
Solution Approach 1:
The user's own body weight and movement serve as the power source for the lifting mechanism. As the user moves from seated to standing position, their body weight drives the four-bar mechanism through the natural J-shaped or S-shaped path, eliminating the need for external power sources like compressed air cylinders or gas springs
Solution Approach 2:
The lifting power function is extracted from external power sources and transferred to the user's own body mechanics. The device removes the cumbersome power source components entirely, relying instead on the user's natural movement to activate the lifting mechanism
2Ease of operation
If conventional devices lift along an unnatural path, then lifting function is achieved, but user comfort and stability are reduced
Solution Approach 1:
The four-bar mechanism is specifically designed to guide the lift point along a J-shaped or S-shaped curved path that mimics natural human standing motion. This curved trajectory, rather than a straight vertical lift, replicates the biomechanics of natural rising from a chair, improving both comfort and stability
Solution Approach 2:
The lifting path parameters are changed from conventional straight-line motion to natural J-shaped or S-shaped trajectories. By adjusting the mechanism geometry to produce these specific path shapes, the device matches human biomechanics and improves user experience
3Power
If conventional devices require user exertion to compress gas springs, then lifting is achieved, but user fatigue increases
Solution Approach 1:
The user's body weight and natural movement serve as the power source, eliminating the need to exert additional force to compress springs or activate power sources. The mechanism converts the user's own movement into lifting power throughout the entire range of motion
Solution Approach 2:
The lifting action continues smoothly throughout the entire standing motion without requiring intermittent user exertion to activate power sources. The four-bar mechanism maintains continuous lifting assistance from the seated position through the full range of motion to standing
4Force
If conventional devices position handles behind and beneath the user, then resistance is provided for rising, but the sitting scenario becomes awkward
Solution Approach 1:
The lifting force application point is moved from a position behind and beneath the user to a point on the user's body (such as the shoulder or hip region) that allows natural sitting and standing motions. This spatial repositioning eliminates the awkward leaning backward and weight shifting required by conventional handle placements
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 apparatus enables stable, efficient, and natural lifting and lowering, reducing user fatigue and discomfort, while also serving as a walker and gait trainer, and providing exercise assistance during rehabilitation.
Implementation Method 1
An actuator and interconnected four-bar lifting mechanism, which includes a crank, a coupler, a rocker, and a frame. Each of the crank, coupler, rocker and frame are rotatably interconnected, and operation of the actuator moves a lift point for connection to a garment worn by a user
Data Source
AI summary
A four bar apparatus and method are provided for lifting, lowering, providing exercise and facilitating self-propelled transit. The apparatus includes an actuator and interconnected four-bar lifting mechanism, which includes a crank, a coupler, a rocker, and a frame. Each of the crank, coupler, rocker and frame are rotatably interconnected, and operation of the actuator moves a lift point of the coupler, with the lift point connectable to a vest-type garment or belt worn by a user of the apparatus, with the lift point following a J shape path or an S shape path to lift the user from a shoulder or hip area, respectively.