Linear Motion Therapy Device Using Worm-Drive Actuator
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Solution Overview
Problem
Current therapy devices for knee or hip rehabilitation after surgery are limited in their ability to provide a full range of motion, are often heavy and difficult to use, and do not allow for precise measurement or proper alignment, leading to inconsistent therapy and potential neglect by patients outside a clinical setting.
Innovation Solution
A lightweight, adjustable linear motion therapy device with a driven worm-drive, thoracic lumbar spine orthosis, and thigh support assembly, allowing for controlled clockwise and counterclockwise rotation and telescopic linear movement, enabling patients to manually control their rehabilitation and maintain proper alignment and measurement of knee flexion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CPM devices are used for post-surgery rehabilitation, then continuous passive motion is provided, but the device is heavy and difficult to handle
Solution Approach 1:
The device enables patients to perform self-service therapy by lying supine and manually flexing their knee through heel slides, eliminating the need for heavy motorized equipment. The patient independently controls the motion using their own body weight and effort, with optional assistance from a therapist or family member.
Solution Approach 2:
The invention extracts the essential therapeutic function (knee flexion through heel slides) from the complex motorized CPM system, removing unnecessary mechanical complexity and weight while retaining the core rehabilitation benefit.
2Ease of operation
If manual therapy with heel slides is used, then knee flexion is achieved, but precise measurement and alignment control are difficult
Solution Approach 1:
The device incorporates a goniometer that provides real-time visual feedback of knee flexion angle through a pointer and degree markings on a circular scale. This allows patients to see their progress and maintain proper alignment, with the therapist able to measure and record precise angles.
Solution Approach 2:
The circular protractor scale is positioned at the knee joint center, creating a reference frame that naturally indicates proper alignment. When the knee is correctly positioned, the pointer aligns with the 0-degree mark, providing an intuitive visual cue for proper form.
3Force
If NKTM tables are used for therapy, then resistance training is provided, but the device is complex and requires extensive setup time
Solution Approach 1:
The device applies resistance locally at the heel through a strap and weight system, rather than requiring a complex full-body positioning apparatus. The resistance can be easily adjusted by changing weights, and the setup is simplified to essential components only.
Solution Approach 2:
The device allows dynamic adjustment of resistance levels by adding or removing weights, and the knee flexion angle can be varied throughout the range of motion. The setup transitions from simple initial positioning to flexible intermediate adjustments based on patient progress.
4Ease of operation
If prior art therapies are used, then some knee flexion is achieved, but consistent daily practice is difficult without clinical supervision
Solution Approach 1:
The device is designed for independent home use, allowing patients to perform therapy daily without requiring a therapist's presence. The simple setup and visual feedback system enable self-monitoring of progress, ensuring consistent practice.
Solution Approach 2:
The goniometer provides immediate visual feedback of knee flexion angle, allowing patients to see their progress and maintain motivation. This self-monitoring capability ensures proper form and encourages daily practice without clinical supervision.
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 effectively increases the range of motion, reduces soft tissue stiffness, and prevents scar tissue formation, allowing for consistent and effective rehabilitation both in and out of a clinical setting, with the ability to adapt to individual patient sizes and needs.
Implementation Method 1
a base with a driven worm-drive, a footpad assembly affixed to a worm receiver disposed on the worm-drive
Data Source
AI summary
A linear motion therapy device that has a single semi-enclosed worm-driven actuator (guide bar) with one end attached to a cantilevered and adjustable foot and heel support. The opposite end of the actuator is attached to a corset the person wears while in a supine position called a thoracic lumbar spine orthosis (TLSO). Next to the corset, but attached to the actuator is a motor, a height adjustment screw, and a stabilizer plate. A cord is attached to a push button hand control device for moving the foot support along the guide bar in a forward or reverse direction. Movement can be stopped at any time. A patient also wears a constraint that wraps around the thigh called a thigh support that attaches to the actuator with a pivotal and adjustable arm. This device can be adjusted to either leg.