Orthogonal Axis Coupling for Safe Limb Stretching
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Solution Overview
Problem
Manual manipulation for physical therapy can lead to overextension or incorrect movement of limbs, potentially causing injury or hindering recovery in patients with paralysis or limb injuries, as it lacks precise control over the range of motion.
Innovation Solution
A device with a foot support and coupling system allowing rotation about three orthogonal axes, featuring universal joints and pneumatic locks to control and limit movement, ensuring safe and controlled stretching within the normal range of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual manipulation is used for limb stretching, then the therapist can directly control the limb movement, but the risk of overextension and injury increases
Solution Approach 1:
The patent introduces a mechanical device as an intermediary between the therapist and the patient's limb. The device includes a support structure with multiple axes of rotation that physically interfaces with the limb, allowing the therapist to control movement through the device rather than direct manual manipulation. This intermediary mechanism provides controlled resistance and prevents overextension while maintaining therapeutic effectiveness.
Solution Approach 2:
The patent replaces the purely manual mechanical system with a hybrid system that incorporates mechanical guides, bearings, and rotational axes. These mechanical elements substitute for human muscle control, providing consistent, repeatable movements along precise axes while preventing movements outside the safe range of motion.
2Adaptability or versatility
If manual stretching is performed without guidance, then the therapist has flexibility in movement technique, but the movement may not follow the correct axis
Solution Approach 1:
The patent segments the movement control into distinct rotational axes (first axis, second axis, third axis) that correspond to different planes of motion. Each axis is controlled independently through separate bearings and support structures, allowing precise control of movement along each anatomical axis while maintaining overall flexibility in combining these movements for comprehensive therapy.
Solution Approach 2:
The device provides universal control over multiple planes of motion through its three-axis rotational capability. The same basic mechanical structure with its bearing system can accommodate various stretching techniques and movement patterns, making the device versatile for different therapeutic needs while ensuring all movements follow anatomically correct axes.
3Productivity
If the limb is stretched beyond normal range of motion, then more aggressive therapy can be applied, but patient injury or recovery prevention occurs
Solution Approach 1:
The patent incorporates mechanical stops and range-limiting features that prevent the limb from being moved beyond its safe range of motion. These preliminary protective measures are built into the device structure itself, creating counter-action before dangerous movements can occur. The bearings and support structures are designed to physically block movements that would exceed normal anatomical limits.
Solution Approach 2:
The device provides tactile feedback to the therapist through its mechanical resistance and range limits. When the limb approaches the end of its safe range of motion, the mechanical structure provides increasing resistance and physical boundaries, allowing the therapist to sense and adjust the therapy intensity in real-time without risking injury.
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 controlled and safe stretching, preventing overextension and ensuring movements are around the correct axes, thereby facilitating effective and injury-free physical therapy for patients.
Implementation Method 1
The coupling has a first axis of rotation, a second axis of rotation, and a third axis of rotation, and the axes are orthogonal to the each other. A first foot support axis extends between the proximal and distal ends of the foot support and is rotatable about the first axis and the third axis
Data Source
AI summary
Various implementations include a device for assisting with and controlling stretching of a limb of a patient. The device includes a limb support for receiving the limb, a base, and a coupling that rotatably couples the limb support and the base. The coupling allows the limb support to rotate through various axes of rotation individually, depending on the range of motion expected for the limb. For example, for a device designed for the foot, the coupling allows a foot support to rotate about a first axis, a second axis, and a third axis, wherein the three axes are orthogonal to each other. In other implementations, the device may be designed for other portions of limbs, such as the hand, the forearm, the upper arm, the lower leg, and the upper leg.