Auto-Injector Audible End-of-Injection Feedback and Needle Shielding
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Solution Overview
Problem
Existing automatic injection devices lack intuitive feedback for users to confirm the completion of the injection and may pose risks of accidental needlestick injuries due to inadvertent activation or incomplete injections.
Innovation Solution
The device generates an audible feedback at the end of the injection through the cooperation between the activator and central piece, utilizing mechanisms like the disengagement of a clipped connection or a shock between components to produce a sound, ensuring the user knows the injection is complete and preventing accidental needle exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If visual feedback mechanisms are used to indicate injection completion, then information about injection status is provided, but the feedback is not sufficiently intuitive for all users
Solution Approach 1:
The patent implements an audible feedback mechanism through a sound generation element that produces a distinct sound when the plunger rod reaches its retracted position, indicating complete injection. This auditory feedback complements or replaces visual feedback mechanisms, providing more intuitive and universally understandable information about injection completion status.
Solution Approach 2:
The patent replaces purely visual feedback mechanisms with an audible feedback system using a sound generation element. This substitution provides more intuitive feedback that is easier for all users to understand, including those with visual impairments or in situations where visual attention is limited.
2Reliability
If the device requires multiple activation steps to prevent inadvertent activation, then safety is improved, but device complexity increases
Solution Approach 1:
The patent employs a safety shield that must be moved to a specific position before the plunger rod can be activated. This preliminary action ensures that the device is properly positioned and the user is intentional about activation, preventing inadvertent activation while maintaining a relatively simple overall device structure.
Solution Approach 2:
The device is divided into functional segments including a safety shield, plunger rod, and sound generation element. Each segment performs a specific function in the activation sequence, allowing for controlled multi-step activation while maintaining modularity and ease of manufacture.
3Object-affected harmful factors
If the needle is covered by a safety shield, then accidental needlestick injury is prevented, but the user cannot easily confirm proper insertion depth
Solution Approach 1:
The patent uses audible feedback from the sound generation element to confirm that the plunger rod has fully retracted, which indicates proper injection depth and completion. This feedback mechanism works in conjunction with the safety shield, allowing users to confirm proper insertion and injection completion without exposing the needle.
4Loss of information
If the device provides audible feedback at the end of injection, then user confirmation of completion is improved, but device complexity increases
Solution Approach 1:
The sound generation element serves multiple functions: it provides audible feedback for injection completion, can serve as part of the activation mechanism, and may contribute to the overall structural integrity. This multi-functionality reduces the need for separate dedicated components, minimizing the increase in device complexity.
Solution Approach 2:
The patent integrates the sound generation element with existing device components such as the plunger rod or housing, merging multiple functions into a single integrated structure. This approach provides audible feedback while minimizing the increase in overall device complexity and component count.
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 device provides clear audible confirmation of injection completion and ensures safety by preventing accidental needle exposure, making it user-friendly and safe for self-administration, even in emergency situations.
Implementation Method 1
The plunger rod is urged in the distal direction by a first spring
Implementation Method 2
the safety shield is urged in the distal direction by a second spring
Implementation Method 3
a cam configured to transform the proximal movement of the safety shield into a distal movement of the activator
Implementation Method 4
a sound is generated at the end of the injection, which can be heard by the user... The sound may be created by the disengagement of a clipped connection
Data Source
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AI summary
The present disclosure relates to an automatic injection device (1) comprising: - a body (10); - a medical container (20) comprising a barrel (24) containing a product for injection, a distal tip (23) provided with an injection needle (22) and a stopper (25) in sliding engagement within the barrel, the medical container being slidably arranged in the body (10) between a proximal position and a distal position; - a safety shield (60) slidably mounted within the body (10) between a distal initial position and a proximal second position; - a plunger rod (40) slidably arranged in the body (10), comprising a hollow shaft (41) including an inner axial abutment (45) and a distal flange (42) adapted to push the stopper (25) in the distal direction, the plunger rod comprising a proximal flange (43) releasably locked in the initial position by at least one flexible arm (140) of the body; - a cam (70) cooperating with the safety shield (60) so that a translation of the safety shield (60) from the distal safety position to the proximal second position causes the cam (70) to rotate within the body (10) to an unlocking position; - an activator (80) slidably mounted at a proximal end of the body (10), the activator being movable between an initial position in which the activator is proximally spaced from the flexible arms (140) and an unlocking position in which the activator causes the flexible arms (140) to deflect outwardly to release the proximal flange (43) of the plunger rod, thereby allowing the plunger rod to move in the distal direction; and - a central piece (90) comprising a proximal head (91, 93) and a distal stop (92), the central piece (90) extending in the hollow shaft (41) of the plunger rod such that the proximal head is locked by a retention member (85) of the activator proximally from the proximal flange (43) of the plunger rod in the initial position, so that, when the plunger rod moves in the distal direction, the plunger rod slides distally along the central piece (90) until the stop (92) engages the abutment (45), wherein the retention member (85), the stop (92), the proximal head (91, 93) and the abutment (45) are designed to allow disengaging either the central piece (90) from the activator (80) or the plunger rod (40) from the central piece (90) at the end of the injection such that said disengagement results in the generation of a sound.