Automatic Injection Device Cam Unlocking Mechanism
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Solution Overview
Problem
Existing automatic injection devices require a three-step process for activation, which can be too complex and time-consuming for emergency situations, such as administering adrenaline during anaphylaxis.
Innovation Solution
A medical device for automatic injection that simplifies the activation process to only two steps: removing the cap and pressing the safety shield onto the patient's skin, utilizing a cam and activator mechanism to unlock the plunger rod for injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-step activation process is used (removing cap, pushing device onto skin to unlock button, pressing button), then the device safety is improved by preventing accidental activation, but the ease of operation deteriorates and the time required for injection increases
Solution Approach 1:
The patent combines the safety shield pushing action with the button unlocking action into a single integrated mechanism. When the user pushes the safety shield onto the patient's skin, this single action simultaneously completes the safety shield deployment and unlocks the injection button through the cam mechanism, eliminating the need for separate steps.
Solution Approach 2:
The cam mechanism is pre-configured such that pushing the safety shield to a specific position automatically triggers the button unlock through the cam's rotational geometry. This preliminary mechanical arrangement ensures that when the user applies the device to the skin, the unlocking action occurs automatically without requiring additional user input.
2Reliability
If a three-step activation process is used, then the device safety is improved, but the time required for injection increases
Solution Approach 1:
The patent merges the safety shield deployment and button unlocking into one simultaneous action. The cam mechanism ensures that pushing the safety shield the required distance automatically triggers the button unlock, eliminating sequential steps and reducing total injection time while maintaining safety.
3Reliability
If the button is locked until the safety shield is pushed sufficiently, then the device cannot be activated inadvertently is improved, but the ease of operation deteriorates
Solution Approach 1:
The cam mechanism automatically performs the button unlocking action based solely on the user's action of pushing the safety shield. The system serves itself by using the safety shield's movement to trigger the unlocking mechanism, eliminating the need for separate manual unlocking actions and simplifying the overall operation.
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 improves ergonomics and reduces the time required for injection, making it easier to use in emergency situations while maintaining safety by preventing accidental needlestick injuries.
Implementation Method 1
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
Data Source
AI summary
The disclosure relates to an automatic injection device including a body; a medical container including finding 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; 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; 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; an activator slidably mounted at a proximal end of the body, the activator cooperating with the cam so that a rotation of the cam to the unlocking position causes the activator to move in the distal direction. In the initial position, the activator is proximally spaced from the flexible arms and, when the cam is in the unlocking position, the activator causes the flexible arms to deflect outwardly to release the proximal flange of the plunger rod, thereby allowing the plunger rod to move in the distal direction to push the medical container.