Autoinjector End-of-Dose Feedback Mechanism
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Solution Overview
Problem
Current autoinjectors often fail to provide a clear and distinct tactile indication that a full dose has been administered, leading to potential underdosing due to the difficulty in recognizing auditory or tactile feedback in noisy environments or with weak tactile signals.
Innovation Solution
The injection device incorporates an end-of-dose mechanism with a feedback element that moves in a direction opposite or parallel to the activation direction, providing a strong tactile feedback through a lengthwise movement, which is separate from the injection mechanism, allowing for direct perception by the user, and can include additional auditory or visual signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If auditory or weak tactile feedback mechanisms are used to indicate end of dose, then the device complexity is reduced, but the reliability of dose completion recognition deteriorates in noisy environments or for users with diminished sensory perception
Solution Approach 1:
The feedback mechanism is segmented into multiple independent channels: a strong tactile feedback element (push button returning to initial position), an audible feedback element (click sound from cam mechanism), and a visual feedback element (transparent plunger showing full delivery). This segmentation ensures that at least one reliable feedback channel is available regardless of environmental conditions or user sensory limitations.
Solution Approach 2:
The patent implements multiple feedback loops to confirm dose completion. The primary feedback is the strong tactile sensation of the push button returning to its initial position, supplemented by audible click sounds from the cam mechanism and visual confirmation through the transparent plunger. This multi-layered feedback approach significantly improves reliability of dose completion recognition.
2Reliability
If a strong tactile feedback mechanism with lengthwise movement is implemented, then the reliability of dose completion recognition is improved, but the device complexity increases due to separate feedback mechanism
Solution Approach 1:
The feedback mechanism is merged with the delivery mechanism components. The push button that activates injection also provides the strong tactile feedback when it returns to its initial position. The cam mechanism that controls the plunger movement also generates the audible click sound. This merging reduces overall device complexity while maintaining reliable feedback.
Solution Approach 2:
Existing components are designed to serve multiple functions. The push button serves both as the activation mechanism and the primary tactile feedback element. The cam mechanism serves both to control plunger movement and generate audible feedback. The transparent plunger serves both to contain the medicament and provide visual feedback. This multi-functionality reduces the need for separate dedicated feedback components.
3Reliability
If visual indication mechanisms are used to confirm full dose delivery, then the reliability of dose completion recognition is improved for some users, but the ease of operation deteriorates in environments with poor lighting or for visually impaired users
Solution Approach 1:
The feedback system is segmented into multiple sensory channels including tactile (strong push button return), audible (click sounds from cam mechanism), and visual (transparent plunger). This segmentation ensures that users with different sensory capabilities can all reliably recognize dose completion through their dominant sensory modality.
Solution Approach 2:
The patent implements strong multi-modal feedback that is immediately perceivable regardless of lighting conditions or visual acuity. The strong tactile feedback of the push button returning to its initial position and the audible click sounds provide reliable dose completion confirmation that does not depend on visual perception or lighting conditions.
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
This design ensures that users, especially in challenging environments or for older or younger users, can confidently recognize the end of the dose, preventing underdosing and ensuring complete medicament delivery, with enhanced tactile feedback that avoids errors and skin irritations.
Implementation Method 1
the end of dose mechanism is further operable to force the feedback element to move into a feedback direction
Implementation Method 2
delivery mechanism for injection of a medicament, preferably through a needle
Data Source
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AI summary
The invention refers to an injection device comprising a delivery mechanism for injection of a medicament, preferably through a needle, and an end of dose mechanism comprising a feedback element, wherein the end of dose mechanism is operable to be activated at a position at which the delivery mechanism reaches the end of the dose and the end of dose mechanism is further operable to force the feedback element to move into a feedback direction which is opposite or parallel to the activation direction of a release button and/or into the longitudinal direction, wherein the activation direction is preferably a longitudinal direction of the device.