Gait Assist Device Pivot Axis Alignment and Torque Reduction
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Solution Overview
Problem
Conventional gait motion assisting apparatuses attached to knee-ankle-foot orthoses face challenges in reducing size and driving torque while maintaining accurate alignment of pivot axes, leading to increased thickness and torque requirements.
Innovation Solution
The apparatus is configured with a ball stud and accommodation depression arrangement that allows for attachment at three vertical positions, reducing size and torque needs by positioning the actuator-side pivot axis coaxially with the brace-side pivot axis, and incorporating a bevel gear mechanism for efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bearing structure is added to the inner wall of the casing to support the driving shaft, then the reliability of the driving shaft support is improved, but the thickness of the gait motion assisting apparatus increases
Solution Approach 1:
The patent combines the bearing structure with the inner wall of the casing by providing recesses directly formed in the inner wall surface. This integration eliminates the need for separate bearing components, maintaining reliable driving shaft support while reducing the overall thickness of the apparatus.
2Device complexity
If the proximal end portion of the driving arm is supported by the intermediate portion of the driving shaft, then the structural complexity is reduced, but the length between the driving arm and lower leg frame increases, requiring larger driving torque
Solution Approach 1:
The patent repositions the driving arm support from an intermediate portion of the driving shaft to the distal end portion of the driving shaft. This dimensional rearrangement shortens the moment arm between the driving arm and lower leg frame, reducing the required driving torque while maintaining structural simplicity.
3Manufacturing precision
If the accommodation depression is formed in a fixed plate attached to the outer surface of the inner wall, then the alignment precision of pivot axes is improved, but the apparatus thickness increases
Solution Approach 1:
The patent integrates the accommodation depression directly into the inner wall of the casing rather than using a separate fixed plate. This merging maintains precise pivot axis alignment through direct formation in the casing wall while eliminating the additional thickness required for a separate mounting plate.
Data Source
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AI summary
A gait motion assisting apparatus (100A, 100B) of the present invention can be connected to a knee-ankle-foot orthosis (1) at three different positions in a vertical direction by upper, intermediate and lower connecting mechanisms (220, 250, 260). The intermediate connecting mechanism (250) includes a ball stud (251) arranged at the knee-ankle-foot orthosis (1) extending outward in the user width direction on a brace-side pivot axis line X and an accommodation depression (258) opened toward the knee-ankle-foot orthosis (1) on the actuator-side pivot axis line Y so that the ball stud (251) can be inserted thereinto. The accommodation depression (258) is arranged at an innermost power-transmitting member among a driving arm (150) and components of a transmission mechanism (140) operatively transmitting rotational power from an electric motor (130) to the driving arm (150).