Spiral Spring Braking Mechanism for Orthotic Joints
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Solution Overview
Problem
Existing joint devices for orthoses and prostheses require complex and bulky hydraulic systems for braking, which are inefficient in terms of space and weight, and lack discreetness when worn under clothing.
Innovation Solution
A joint device utilizing a spiral spring with contoured contact surfaces that creates a high braking moment through friction, allowing for compact design and adjustable braking via an actuator, with optional sensor integration for adaptive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic damping or braking systems are used, then reliable braking function is achieved, but device complexity and space requirements increase significantly
Solution Approach 1:
The patent extracts the essential braking function from complex hydraulic systems and implements it using a simple spiral spring mechanism with friction contact surfaces. The spiral spring is braced in the direction of contact surfaces about a rotation axis, causing lateral flanks to contact the surfaces and generate friction-based braking moment, eliminating the need for hydraulic components.
Solution Approach 2:
The patent replaces hydraulic damping systems with a purely mechanical spiral spring-based friction braking system. The spiral spring, when braced, creates lateral contact with contoured surfaces through mechanical friction, substituting the hydraulic fluid-based damping mechanism with a solid-mechanics-based solution.
2Reliability
If hydraulic damping systems are used, then reliable braking function is achieved, but weight and space consumption increase
Solution Approach 1:
The patent extracts the essential braking function from heavy hydraulic systems and implements it using a lightweight spiral spring mechanism. The spiral spring, when braced in the direction of contact surfaces, generates sufficient friction-based braking moment with minimal mass, eliminating the weight of hydraulic pumps, reservoirs, and fluid systems.
3Reliability
If hydraulic damping systems are used, then reliable braking function is achieved, but the joint device cannot be worn discreetly under clothing
Solution Approach 1:
The patent extracts the braking function from bulky hydraulic systems and implements it in a compact form using a spiral spring mechanism with contoured contact surfaces. The bracing of the spiral spring in the direction of contact surfaces creates an efficient friction interface that achieves reliable braking in a minimal volume, enabling discreet wearability under clothing.
4Force
If high braking moment is achieved through friction, then low switching force is required, but friction surface area must be increased
Solution Approach 1:
The patent uses contoured contact surfaces with radially conical or radially curved designs to increase the friction surface area. The curvature of these surfaces corresponds to the successive radially outward turns of the spiral spring, creating progressive braking action and maximizing friction contact without requiring excessive surface area.
Solution Approach 2:
The patent employs a spiral spring mechanism that dynamically adjusts the contact pressure and friction surface engagement. When the spiral spring is braced in the direction of contact surfaces, it progressively engages the lateral flanks with the contoured surfaces, creating a dynamic friction interface that adapts to the applied load and switching requirements.
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 joint device achieves reliable braking with low switching force and minimal space usage, providing progressive braking and self-reinforcement, while ensuring discreet wearability and adaptive control through actuator and sensor systems.
Implementation Method 1
a very high braking moment to be built up by friction at very low switching forces and switching paths
Implementation Method 2
the contact surfaces are contoured, in particular with a radially conical or radially curved design, to increase the friction surface
Data Source
AI summary
A joint device for an orthoses or prostheses includes an upper part, a lower part mounted on the upper part in such a way as to turn about a pivot axis, and braking means that brakes or blocks a pivoting movement of the lower part relative to the upper part. The braking means includes a spiral spring arranged between two contact surfaces and is mounted such that it can be braced in the direction of the contact surfaces about a rotation axis parallel to the pivot axis.