Automatic Injection Device with Safety-Shield Cam Activation
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Solution Overview
Problem
Existing automatic injection devices require a multi-step process that is too complex for emergency situations, risking inadvertent activation and accidental needlestick injuries.
Innovation Solution
A simplified injection device design requiring only two actions: removing a cap and pressing a safety shield onto the skin, utilizing a cam mechanism to unlock a button and activate the plunger rod for injection, ensuring safety and ergonomic operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-step injection process is used to ensure safety, then the device prevents inadvertent activation, but the injection process becomes too complex and time-consuming for emergency situations
Solution Approach 1:
The patent combines the safety shield movement and button unlocking functions into a single integrated mechanism. When the safety shield is pushed distally, it simultaneously unlocks the button and enables plunger rod movement, reducing the injection process to two simple actions while maintaining safety through the shield's position-dependent control
2Object-affected harmful factors
If a safety shield covering the needle tip is used, then accidental needlestick injuries are prevented, but the device structure becomes more complex
Solution Approach 1:
The safety shield serves multiple functions: it covers the needle tip to prevent accidental needlesticks, acts as a control mechanism for the cam and button unlocking, and guides the injection process. This multi-functionality reduces the need for separate safety components, simplifying the overall device structure while maintaining protection
3Reliability
If the button is locked during storage and transport, then inadvertent activation is prevented, but the device requires additional steps to unlock before injection
Solution Approach 1:
The button is pre-locked in a safe position during storage and transport. The locking mechanism is designed to be automatically released when the safety shield is pushed distally during injection, eliminating the need for a separate unlocking step and reducing preparation time while maintaining safety
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
Facilitates rapid and safe injection by reducing the steps to two, enhancing ergonomics, and preventing accidental needlestick injuries, even in emergency scenarios.
Implementation Method 1
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
Implementation Method 2
the button is allowed to move in the distal direction, wherein the outer shell (90) pushes the unlocked button (80) in the distal direction so as to cause the at least one flexible arm (140) of the body (10) to deflect outwardly to release the proximal flange (44) of the plunger rod (40)
Implementation Method 3
the plunger rod (40) being movable in a distal direction when the proximal flange (44) is unlocked to engage the stopper (25) with a distal tip of the plunger rod (40)
Data Source
AI summary
The present disclosure relates to an automatic injection device including a body; a medical container including a barrel containing a product for injection, a distal tip provided with an injection needle and a stopper in sliding engagement within the barrel, the medical container being slidably arranged in the body between a proximal position and a distal position; a safety shield slidably mounted within the body between a distal initial position and a proximal second position; an outer shell enclosing the body, the outer shell being slidably movable in a distal direction relative to the body; a plunger rod slidably arranged in the body, the plunger rod including a proximal flange releasably locked in a proximal initial position by at least one flexible arm of the body, the plunger rod being movable in a distal direction when the proximal flange is unlocked to engage the stopper with a distal tip of the plunger rod; a cam cooperating with the safety shield so that a translation of the safety shield from the distal safety position to the proximal second position causes the cam to rotate within the body to an unlocking position; and a button slidably mounted at a proximal end of the body. In the initial position, the button is prevented from moving distally by the cam and, when the cam is in the unlocking position, the button is allowed to move in the distal direction. The outer shell cooperates with the safety shield and the button such that, when a user pushes the outer shell onto a patient's skin to perform an injection, the safety shield causes the cam to move to the unlocking position so as to unlock the button and the outer shell further pushes the unlocked button in the distal direction so as to cause the at least one flexible arm of the body to deflect outwardly to release the proximal flange of the plunger rod, thereby allowing the plunger rod to move to the injection position.