Joint Rotation Tool With Continuous Torque Across Full Range
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Solution Overview
Problem
Current rehabilitation and training tools for shoulder, elbow, and wrist joints primarily provide linear resistance, failing to deliver consistent rotational torque, which is essential for effective strengthening and mobilization, and are often bulky and unsuitable for home use.
Innovation Solution
A rotational exercise and stretching tool with a secure mount, torque-generating mechanism, and ergonomic lever arm that provides consistent resistive torque, allowing for concentric, eccentric, and isometric exercises, and can be mounted to various structures for versatile use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional rehabilitation tools (dumbbells, elastic bands) are used, then the device is simple and inexpensive, but it provides linear resistance instead of consistent rotational torque
Solution Approach 1:
The patent introduces a cable mechanism as an intermediary between the user's rotational movement and the resistance force. The cable connects the lever arm to a weight stack or resistance element, converting linear weight resistance into rotational torque through the cable's tension transmission. This intermediary mechanism enables consistent rotational torque delivery without requiring complex mechanical resistance systems directly at the joint.
Solution Approach 2:
The patent replaces traditional direct mechanical resistance (dumbbells, elastic bands) with a cable-based resistance system. Instead of relying on the user's body weight or elastic band tension, the system uses a cable connected to a controlled resistance source (weight stack or spring mechanism), substituting a simpler mechanical system with one that better delivers rotational torque while maintaining ease of use.
2Force
If specialized rotational resistance machines are used, then consistent rotational resistance is provided, but the machine is large and expensive
Solution Approach 1:
The patent extracts the essential rotational resistance function from large specialized machines and implements it through a simplified lever arm mechanism. By isolating the core function (providing rotational resistance) and removing unnecessary machine components (seat, arm support, complex lever systems), the design achieves consistent rotational resistance in a compact, space-efficient format suitable for home use.
Solution Approach 2:
The lever arm mechanism serves multiple functions: it provides the rotational resistance pathway, guides the user's limb through the arc of motion, and transmits force from the resistance source to the joint. This multi-functionality eliminates the need for separate specialized components found in large machines, reducing overall device size while maintaining resistance consistency.
3Adaptability or versatility
If elastic bands are used, then the device is simple and portable, but resistance varies based on angle of stretch with limited effective arc
Solution Approach 1:
The patent changes the resistance parameter from variable (elastic band tension changing with stretch angle) to controlled and consistent. By using a weight stack or spring mechanism connected through a cable, the resistance force remains relatively constant throughout the arc of movement, or can be precisely controlled to increase/decrease as needed. This parameter control ensures consistent rotational torque delivery across the full range of motion.
Solution Approach 2:
The cable mechanism maintains continuous and consistent resistance throughout the entire arc of movement. Unlike elastic bands that lose effectiveness at certain angles, the cable-connected weight stack or spring mechanism provides uninterrupted rotational resistance from the start to the end of the movement arc, ensuring continuous useful action on the target joint.
4Ease of operation
If wrist curls with light dumbbells are used, then the exercise is simple, but linear resistance does not align with natural arc of wrist rotation
Solution Approach 1:
The patent introduces dynamic alignment through the lever arm mechanism, which naturally guides the user's limb through the correct arc of motion. The lever arm's geometry and cable attachment points are designed to maintain proper alignment between the resistance force and the joint's natural rotational axis throughout the movement. This dynamic alignment ensures that even simple exercises like wrist curls deliver force in the correct direction, matching the natural arc of wrist rotation.
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 targeted joint-specific rotational resistance, reducing complexity and variability, suitable for both rehabilitation and performance applications, and adaptable to different user positions and angles.
Implementation Method 1
A torque-generating mechanism is operably coupled to the mount and provides rotational resistance—typically bidirectional and variable—to accommodate different users and exercise needs.
Data Source
AI summary
A joint rotational exercise and stretching tool for strengthening muscles and connective tissues, particularly for shoulder internal and external rotation, with further applicability to the wrist, elbow, and hip. The device includes a mount, torque-generating mechanism, and ergonomic lever arm configured to align with anatomical joint axes. It enables concentric, eccentric, isometric, and passive modes of use. Unlike traditional tools that provide linear resistance or partial-range torque, this invention delivers continuous rotational resistance across the full arc of motion. Configurable mounting and ergonomic adjustments allow use across various joints, limb lengths, and exercise positions. Suitable for rehabilitation, injury prevention, and performance training in clinical, home, or athletic environments.