Orthopedic Joint Device with Time-Delayed Release Mechanism

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Solution Overview

Problem

Conventional orthopedic joint devices require a high flexion moment to release the holding device, which is not feasible for patients who can only apply a small flexion moment, and reducing the release torque is not safe as it may lead to undesirable flexing during walking.

Innovation Solution

An orthopedic joint device with a flexion moment-controlled holding device that includes an actuating element coupled with a delay element, allowing a lower flexion moment to be applied over a longer period, ensuring the integral of the moment is sufficient for release without abrupt unlocking, and featuring a mechanical or hydraulic damper system for controlled unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high flexion moment is required to release the holding device, then safety during walking and standing is improved, but the device becomes unusable for patients who can only apply a small flexion moment

Engineering Contradiction:

Improvesafety during walkingVSAvoidability to release for sitting

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The delay element performs a preliminary action by accumulating the applied flexion moment over time. When the integral of the moment over the delay period exceeds a threshold, the holding device releases. This allows patients to apply a low continuous moment (by simply sitting down) rather than requiring them to generate a high instantaneous moment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically evaluates the flexion moment over time through the delay element. The release condition is not a static threshold but a dynamic integration process that accumulates moment over a predetermined period. This transforms the static high-threshold release mechanism into a dynamic time-integrated release mechanism.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the release moment is reduced to enable patient operation, then ease of operation is improved, but safety is compromised due to undesirable flexing during walking

Engineering Contradiction:

Improveability to release for sittingVSAvoidstability during walking

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The delay element ensures continuous evaluation of the flexion moment over the predetermined period. The system continuously integrates the moment rather than checking at discrete intervals, ensuring that the release only occurs when sustained moment application confirms the user's intent to sit, preventing accidental release during walking.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of operation

If a delay element is introduced to enable low moment release, then ease of operation is improved, but device complexity increases

Engineering Contradiction:

Improveautomatic unlocking capabilityVSAvoidmechanical structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The delay element can be implemented using pneumatic or hydraulic principles. A fluid chamber with a piston accumulates pressure as the flexion moment is applied. The fluid's compressibility and flow characteristics naturally provide the time delay effect, eliminating the need for complex mechanical timers or electronic sensors while achieving the same functional result.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The delay element is designed to automatically perform the time-integration function without external control systems. The mechanical or hydraulic delay element self-regulates the release timing based on the applied moment and predetermined delay characteristics, eliminating the need for sensors, microprocessors, or complex control circuits.

Inventive Principle:

Principle #25Self-service

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 safe and automatic unlocking of the joint device without manual intervention or complex sensors, maintaining high locking torque for safety during walking and standing, while allowing controlled flexion for sitting by adjusting the delay period according to user needs.

Implementation Method 1

an actuating element (60) coupled to a delay element (70) which causes a time-delayed activation of the actuating element (60)

Methodology Applied

Scientific EffectTime delay mechanism:

Implementation Method 2

featuring a mechanical or hydraulic damper system for controlled unlocking

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentEP3897469B1Orthopedic joint device

Publication Date: 2023.01.25 OTTOBOCK SE & CO KGAA

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AI summary

The invention relates to an orthopedic joint device having an upper part (10) and a lower part (30) which is hinged about a pivot axis (20) to said upper part (10), comprising a flexion moment-controlled retainer device (40) that is positioned between the upper part (10) and the lower part (30), blocks a flexion and releases the flexion when a predefined flexion moment is exceeded, wherein a control element (60) is associated with the retainer device (40) and is coupled to a delaying element (70).