Finger Joint Motion Facilitation Device with Perpendicular Bellows Actuators
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Solution Overview
Problem
Existing joint motion facilitation devices are inadequate for facilitating motion of multiple fingers, particularly the thumb, due to the use of a single actuator and difficulty in fitting for patients with finger contracture or broken bones, and often restrict joint motion limits.
Innovation Solution
A joint motion facilitation device with bellows mounted perpendicular to each joint's rotational axis, connected by transmission members, allowing easy installation regardless of joint state, and an air pressure regulation system to generate forces for flexion and extension, with optional bio-monitoring integration for personalized pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single foam portion actuator is used to facilitate motion of all finger joints, then the device structure is simple, but it cannot provide proper flexion and extension motion for multiple fingers including the thumb which has different rotational axis directions
Solution Approach 1:
The patent divides the single actuator into multiple independent bellows actuators, with each bellows dedicated to a specific finger joint. This segmentation allows each actuator to be independently controlled and oriented perpendicular to its corresponding joint's rotational axis, enabling proper flexion and extension motion for each finger including the thumb while maintaining overall system simplicity.
Solution Approach 2:
Each bellows actuator is locally oriented perpendicular to the rotational axis of its corresponding joint, providing directionally appropriate force for each specific joint's motion requirements. This local quality adjustment ensures that each finger joint receives force in the correct direction for its specific anatomical orientation.
2Reliability
If fingers are required to be inserted into the device in an extended state, then the actuator can effectively move joints, but patients with finger contracture or broken bones cannot easily fit the device
Solution Approach 1:
The mounting portion is designed to be dynamically adjustable, allowing the device to accommodate fingers in various states (extended, flexed, or intermediate positions). This dynamic mounting capability enables patients with finger contracture or broken bones to fit the device comfortably while still allowing the bellows actuators to effectively move each joint through its available range of motion.
3Device complexity
If pressure reduction in the closed chamber is insufficient, then the device structure remains simple, but joint motion limits become restricted and sufficient motion cannot be obtained
Solution Approach 1:
The patent implements independent pressure control for each bellows actuator, allowing the pressure parameter to be individually adjusted for each finger joint. This enables sufficient joint motion range to be achieved by optimizing pressure levels for each joint's specific requirements, while the overall system remains relatively simple through the use of standard pressure control mechanisms.
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 easy fitting and sufficient joint motion for each finger, including the thumb, without imposing a burden, and allows for selective facilitation of desired joint motions, improving rehabilitation outcomes.
Implementation Method 1
when the air pressure in the bellows that is communicated with the conduit changes, the bellows expands and contracts, and thus the bellows generates force to facilitate joint motion
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
When air is supplied by an air pressure regulation part to bellows 211 through 213 of finger joint motion facilitation parts 110j (where j=1 , ..., 5), the bellows 211 through 213 expand approximately in the shape of circular arcs, since annular grooves on the side of the bellows 211 through 213 opposing a joint are elastically restrained by elastic members 241 through 243. Due to this, the bellows 211 through 213 cooperate, and exert force in the rotational direction to flex the first through the third joints of a finger from their extended states. Next, when air is exhausted from the bellows by the air pressure regulation part, the bellows 211 through 213 contract. Due to this, the bellows 211 through 213 cooperate, and exert force in the rotational direction to extend the first through the third joints of a finger from their flexed states. The forces generated in this manner are transmitted to the joints by transmission members 231 through 234. As a result mounting becomes simple, and also it is possible to facilitate sufficient joint movement for each joint.