Limb Motion Support Device with Threshold-Activated Spring Transmission
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Solution Overview
Problem
Existing devices for supporting limb motions, such as standing up from a seated or squatting position, require actuators and power supplies, leading to complex and heavy configurations that can be burdensome for users.
Innovation Solution
A limb motion support device featuring a pair of braces with shared spring members and a motion transmission mechanism that generates elastic forces only when the user's limbs are sufficiently bent, eliminating the need for an actuator and power supply by controlling the transmission of motion between the braces and spring members based on bending degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an actuator such as an electric motor is used to generate an assisting force, then the device can perform motion support by controlling the actuator, but the device configuration becomes complicated and heavy due to requiring a power supply unit
Solution Approach 1:
The patent extracts and eliminates the actuator and power supply unit from the device configuration. Instead of using an electric motor to generate assisting force, the invention uses a spring member that passively generates elastic force through the user's own limb motion, thereby removing the complex power supply system while maintaining motion support capability
Solution Approach 2:
The spring member serves itself by automatically generating elastic force in response to the user's limb bending motion. The device uses the user's own motion to activate the spring member, which then provides assisting force without requiring external power supply or control systems, achieving self-service operation
2Reliability
If an actuator such as an electric motor is used to generate an assisting force, then the device can perform motion support by controlling the actuator, but the device becomes heavy and acts as a nuisance for the user
Solution Approach 1:
The patent removes the heavy actuator and power supply unit from the device. The spring member-based passive mechanism significantly reduces device weight while maintaining the ability to provide motion support during limb bending and stretching
Solution Approach 2:
The spring member automatically generates assisting force through the user's own limb motion, eliminating the need for heavy power supply units and actuators, thereby reducing overall device weight and improving user comfort
3Ease of operation
If an assisting force acts in a state where the bending degrees of both legs are relatively small, then the user can smoothly start to bend both legs from the standing state, but the assisting force should not act in this state
Solution Approach 1:
The motion transmission mechanism dynamically changes its transmission state based on the bending degree of the user's limbs. When bending degree is small, the mechanism isolates the spring member from brace movement; when bending degree exceeds the first threshold, the mechanism activates transmission to generate assisting force, and when stretching occurs, transmission is isolated again
Solution Approach 2:
The motion transmission mechanism acts as an intermediary between the braces and the spring member. It selectively transmits or isolates movements based on the bending degree, ensuring the spring member only generates assisting force when the user's limbs are sufficiently bent, preventing unwanted assistance during early bending or stretching phases
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 device provides effective assistance for bending and stretching motions without the bulk and weight of traditional actuator-based systems, ensuring a lightweight and simple configuration that reduces user discomfort.
Implementation Method 1
one or more spring members that generate elastic forces for assisting in a bending and stretching motion of the right and left limbs by an elastic deformation
Data Source
AI summary
Provided is a motion transmission mechanism 30 of a limb motion support device 1A configured so as not to transmit the movements of a pair of braces 10R and 10L attached to right and left legs to spring members 20R and 20L in a state where the bending degrees of the right and left legs are smaller than a predetermined bending degree in the case where both of the right and left legs equipped with the braces 10L and 10R are bent from a stretched state and configured to transmit the movements of the braces 10L and 10R to the spring members 20L and 20R via a wire 31 after the bending degrees of the legs increase to be larger than the predetermined bending degree.