Audible Indicator Using Bistable Resilient Force Member
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Solution Overview
Problem
Existing injection devices, both manual and autoinjector types, face challenges in ensuring that the full dose of medicament is delivered effectively, particularly for users with limited dexterity or strength, and in providing a reliable indication of the end of medicament delivery.
Innovation Solution
An audible indicator is introduced, utilizing a bistable resilient force member that changes conformation from a biased state to a relaxed state upon completion of medicament delivery, generating a distinct audible signal to indicate that the full dose has been dispensed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual button/plunger is used to drive medicament through a needle, then the injection can be administered manually, but the force required may be too high for elderly or child users and the injection may stop if the button is released prematurely
Solution Approach 1:
The resilient force member is configured to automatically transition from a biased state to a relaxed state, self-generating the force needed to drive the plunger and deliver the full dose without requiring continuous manual pressure or user intervention throughout the injection process
Solution Approach 2:
The resilient force member is pre-configured in a biased state that stores energy before the injection process begins. This preliminary energy storage enables the force member to automatically propel the plunger during injection, eliminating the need for continuous manual force application
2Measurement precision
If alignment and administration of the injection device requires dexterity, then precise control during injection is achieved, but elderly, child, or arthritic patients may not have the required dexterity
Solution Approach 1:
The device structure itself provides alignment guidance and stability during injection through its rigid housing and component arrangement, eliminating the need for the user to actively maintain precise alignment or exert dexterous control throughout the injection process
3Device complexity
If no indication is provided that the full dose has been delivered, then the device structure remains simple, but the user cannot confirm that the full effectiveness of the medicament has been achieved
Solution Approach 1:
The resilient force member utilizes a visible conformational change (change in shape/position) as it transitions from biased to relaxed state, providing a clear visual indication to the user that the full dose has been delivered without requiring complex electronic or mechanical indication systems
Solution Approach 2:
The resilient force member generates an audible signal through mechanical vibration or clicking sound during its transition from biased to relaxed state, providing auditory feedback to the user that the injection is complete
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 audible indicator provides a reliable and user-friendly method to confirm that the full dose of medicament has been delivered, enhancing the usability and effectiveness of drug delivery devices, especially for users with dexterity or strength limitations.
Implementation Method 1
The resilient force member may be configured as a bistable spring element. A bistable spring element has two stable states or conformations in which it can rest without support from an external component. In order to move the bistable spring element from one stable state or conformation to the other, energy has to be used to move the bistable spring element into an intermediate state. This energy is then released as the bistable spring moves out of the intermediate state into one of the stable states.
Implementation Method 2
The resilient force member releases stored energy to generate an audible signal when changing from the biased state into the relaxed state due to a transition from the second conformation to the first conformation.
Implementation Method 3
The resilient force member may change from the biased state into the relaxed state by a movement of a plunger, used to displace the drug from a medicament container. For example, the resilient force member may change from the biased state into the relaxed state when the plunger moves towards or reaches a proximal position at the end of a medicament delivery process.
Data Source
AI summary
The disclosure relates to an audible indicator for use with a drug delivery device comprising a bistable resilient force member capable of residing in two states. In a biased state, the resilient force member is biased and stores energy In a relaxed state, the resilient force member is relaxed. The resilient force member releases the stored energy when transitioning from the biased state into the relaxed state, thereby generating an audible signal.