Autoinjector Safety Shield Dynamics for Safe Injection
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Solution Overview
Problem
Self-injection devices often require high force application and are prone to misuse, leading to accidental needle exposure and loss of medicinal product when the user inadvertently displaces the device during the injection process, especially for non-medically educated users.
Innovation Solution
A safety system that allows for automatic injection by transitioning between passive and active states, preventing needle activation unless the device is correctly positioned, featuring a housing and safety shield with deactivating means that ensure the container moves from a passive to an active state, allowing for safe and complete injection even if the user misuses the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a safety system covers the needle on displacement or removal of the injection device, then needle safety is improved, but the injection device becomes unusable and the medicinal product is lost
Solution Approach 1:
The patent applies dynamics by making the safety shield movable rather than fixed. The shield transitions between covering and exposing the needle based on the plunger's position. When the plunger is fully depressed, the shield automatically moves to expose the needle for injection, then returns to cover it afterward. This dynamic behavior allows the device to maintain safety while enabling injection completion, resolving the contradiction between needle protection and reliable injection delivery.
Solution Approach 2:
The patent changes the parameter of the safety shield's position as a function of the plunger's compression state. The shield's position is linked to the plunger's movement: when the plunger is compressed a predetermined distance, the shield moves from a needle-covering position to a needle-exposing position. This parameter change allows the system to adapt its safety behavior based on the injection state, ensuring both safety and injection reliability.
2Force
If high force is required for injection, then injection effectiveness is improved, but user stress increases and misuse risk increases
Solution Approach 1:
The patent applies preliminary action by pre-compressing the plunger before injection. The device is designed so that the plunger is already compressed a predetermined distance before the injection actually begins. This preliminary compression stores energy and positions the mechanism so that the actual injection requires minimal additional force from the user, reducing stress while maintaining injection effectiveness.
Solution Approach 2:
The patent applies self-service by designing the injection mechanism to automatically complete the injection process once initiated. The spring-loaded plunger and safety shield mechanism work automatically: when the user triggers injection, the stored energy in the compressed spring drives the plunger forward to deliver the full dose without requiring the user to maintain force or control the injection rate. This self-service mechanism reduces user stress and prevents misuse.
Data Source
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AI summary
The invention relates to an injection device (1) being in one of a passive and active state, triggering of injection being prevented when said device (1) is in its passive state and permitted when said device (1) is in its active state, having: - a housing (30, 30a, 30b) receiving a container, the container being in one of a passive state and an active state, movement of the container out of its initial position being prevented when the container is in its passive state, and being permitted when the container is in its active state, and - a safety shield (40) coupled with the housing (30) and being movable with respect to the housing along a movement path having a predetermined length, - first retaining means (60, 61, 54a) for maintaining the container (20) in its passive state, - second retaining means (34a, 81b) for maintaining said device (1) in its passive state, said device (1) being characterized in that it comprises: - first deactivating means (50, 53) and second deactivating means (50, 50a) movable coincident with movement of the safety shield (40) so as to place the container (20) in the active state, and the device (1) in its active state.