Automatic Injection Device Cam Unlocking for Two-Step Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automatic injection devices require a multi-step process that can be too complex and time-consuming for emergency situations, such as administering adrenaline during anaphylaxis, and do not adequately prevent accidental needlestick injuries.
Innovation Solution
A self-injection device with a simplified two-step mechanism: removing a cap and pressing a safety shield onto the skin, utilizing a cam and plunger retainer system to unlock and activate the injection, ensuring ergonomic and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-step injection process is used to ensure safety, then accidental activation is prevented, but the injection time increases and becomes too complex for emergency situations
Solution Approach 1:
The patent combines the safety shield movement and button unlocking into a single integrated mechanism. When the safety shield is pushed onto the skin, it automatically triggers the cam mechanism that unlocks the button, merging two previously separate actions (pushing shield + pressing button) into one simultaneous action, thereby reducing injection time while maintaining safety
Solution Approach 2:
The device is pre-configured with the button locked by the cam mechanism during storage and transport. The safety shield is pre-positioned to cover the needle. This preliminary locking configuration ensures that no accidental activation can occur before intentional use, while the pre-set cam mechanism is ready to automatically unlock upon shield activation, eliminating the need for separate manual unlocking steps
2Reliability
If a three-step process (remove cap, push device onto skin, press button) is used, then safety is improved, but the ease of operation deteriorates in emergency situations
Solution Approach 1:
The patent merges the button unlocking function into the safety shield movement itself. The cam mechanism is designed so that the shield's proximal movement automatically rotates the cam to the unlocking position, releasing the button. This eliminates the need for a separate button-pressing step, reducing the process from three steps to two steps (remove cap + push onto skin), thereby improving ease of operation while preserving safety
Solution Approach 2:
The device performs the button unlocking action automatically through the cam mechanism driven by the safety shield movement. The system serves itself by converting the user's single action (pushing shield onto skin) into multiple functions: needle exposure, button unlocking, and injection activation, all without requiring additional manual interventions
3Reliability
If the button is locked during storage and transport, then accidental activation is prevented, but the device complexity increases
Solution Approach 1:
The cam mechanism serves multiple functions: it locks the button during storage and transport, it automatically unlocks the button when the safety shield is activated, and it maintains the safety shield in its protective position. This single multi-functional component replaces what would otherwise require separate locking and unlocking mechanisms, preventing accidental activation while actually reducing overall device complexity
Solution Approach 2:
The cam mechanism acts as an intermediary between the safety shield and the button. It translates the linear movement of the safety shield into rotational movement that controls the button's locked/unlocked state. This intermediary mechanism provides smooth, reliable transition between states while maintaining simplicity through its geometric design rather than requiring complex electronic or mechanical control systems
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, improving ergonomics, and preventing accidental needlestick injuries, even if the device is removed prematurely.
Implementation Method 1
a cam (70) cooperating with the safety shield (60) so that a translation of the safety shield from the distal initial position to the proximal second position causes the cam to rotate within the body to an unlocking position
Data Source
AI summary
The 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 (10) between a proximal initial position and a distal position; a safety shield slidably mounted within the body between a distal initial position and a proximal second position; a plunger rod slidably arranged in the body. A non-circular proximal end releasably locked in a proximal initial position and a distal tip adapted to push the stopper in the distal direction when the proximal end is unlocked; a cam cooperating with the safety shield so that a translation of the safety shield from the distal initial position to the proximal second position causes the cam to rotate within the body to an unlocking position; a plunger retainer pivotally mounted in the body. A non-circular proximal opening arranged distally from the proximal end of the plunger rod in the initial position, said opening and the proximal end of the plunger rod having substantially complementary shapes, the plunger retainer being coupled to the cam so that, in the initial position, the shapes of the proximal end of the plunger rod and of the proximal opening are angularly offset from each other and, in the unlocking position, the shapes of the proximal end of the plunger rod and of the proximal opening are axially aligned, thereby allowing the plunger rod to move in the distal direction through the proximal opening of the plunger retainer.