Autoinjector Controller-Locker Mechanism Against Inadvertent Activation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Autoinjectors are sensitive to drop tests and prone to inadvertent activation, necessitating a robust and simple solution to prevent accidental deployment.
Innovation Solution
An autoinjector design featuring a housing with a movable needle cover, a plunger rod, a retainer, a locker, and a controller, where the locker is connected to the controller to prevent inadvertent activation by ensuring the locker moves only when the controller is activated, allowing for a simpler and cheaper manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the housing supports the force of the injection spring, then the housing must be made of strong materials, but this increases manufacturing cost and complexity
Solution Approach 1:
The patent introduces a controller as an intermediary component between the injection spring and the housing. The controller includes a retainer that supports the injection spring, transferring the force-bearing function from the housing to the controller. This allows the housing to be made of cheaper materials while the controller, which is easier to manufacture, handles the mechanical stress.
2Device complexity
If the retainer is part of the housing, then the housing structure is simplified, but this requires the housing to bear injection spring force and use stronger materials
Solution Approach 1:
The patent segments the housing structure by separating the retainer from the housing. The retainer becomes an independent component that can be manufactured separately and assembled into the housing. This segmentation allows the housing to be made of cheaper materials while the retainer handles the spring force, resolving the contradiction between structural simplicity and manufacturing cost.
3Reliability
If the controller is fixed in the housing, then the housing must prevent activation, but this limits user control and requires robust housing design
Solution Approach 1:
The patent makes the controller dynamic by allowing it to rotate between a storage position (where activation is prevented) and an activated position (where injection can occur). The controller includes a grasping member that enables easy user manipulation. This dynamic design resolves the contradiction by providing both security against inadvertent activation and ease of user control.
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 design effectively prevents inadvertent activation, simplifies manufacturing, and allows for the use of less expensive materials, while maintaining robustness against drop tests.
Implementation Method 1
an initially compressed spring for moving the plunger rod in the distal direction
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The autoinjector (1) includes: a housing (2) extending along a longitudinal axis A; a needle cover (5) coupled to and axially movable with respect to said housing (2) between a first extended position, a retracted position, and a second extended position in which the needle cover (5) moves back in the distal direction to shield an injection needle; a plunger rod (4) axially movable inside the housing (2) between a storage position and an injection end position; a retainer (8), movable with respect to the plunger rod (4) between a blocking position, in which the retainer (8) blocks the plunger rod (4) in the storage position, and a release position, in which the retainer (8) is moved away from the plunger rod (4) to allow axial displacement of the plunger rod (4) from the storage to the injection end position; a locker (9), movable with respect to the retainer (8) between a locking position, in which the locker (9) locks the retainer (8) in the blocking position, and a release position, in which the locker (9) allows movement of the retainer (8) to the release position, movement of the locker (9) from the locking position to the release position being caused by the needle cover (5) moving from the first extended position to the retracted position; and a controller (7), movable with respect to the housing (2), between a storage position which the controller (7) prevents activation of the autoinjector (1) and an activated position allowing for activation of the autoinjector (1), said controller (7) including a grasping member (73) configured for allowing a user to move the controller (7) from the storage position to the activated position. The locker (9) is connected to the controller (7) such that movement of the controller (7) with respect to the housing (2) between the storage and activated position entails movement of the locker (9) with respect to the housing (2) between a corresponding storage and an activated position. The locker (9) includes a blocking member (96) configured for abutting against a stop (281) of the housing (2) as long as the locker (9) is in the storage position, and the blocking member (96) of the locker (9) is moved away from said stop (281) of the housing (2) when the locker (9) is moved to the activated position.