Autoinjector Locking Member Prevents Accidental Actuation
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Solution Overview
Problem
Automatically actuable syringes, or autoinjectors, face the challenge of unintentional actuation due to internal components being displaced rearwardly by inertia when the device is dropped, leading to potential misuse or inefficiency.
Innovation Solution
A medicament delivery device with a housing comprising separable casing parts and a locking member that is axially movable between two positions, engaging with the sleeve to inhibit rearward movement and prevent unintentional actuation, ensuring the device remains secure until intentionally activated by user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the device uses a needle shield that actsuates by displacing internal components rearwardly upon pressing, then the device can be easily actuated by user action, but the device may be unintentionally actuated if dropped onto a hard surface
Solution Approach 1:
A cap is introduced as an intermediary component between the user and the needle shield. The cap must be removed before the device can be actuated, serving as a mediating step that prevents direct transmission of impact forces to the needle shield while allowing intentional actuation after cap removal. This intermediary element effectively decouples the actuation mechanism from accidental activation caused by dropping.
2Reliability
If the locking member engages with the outer surface to inhibit axial movement, then unintentional actuation is prevented, but the device structure becomes more complex
Solution Approach 1:
The housing is segmented into first and second casing parts that can be separably attached. The locking member is integrated into the second casing part, allowing the locking function to be separated from the main housing structure. This segmentation enables the locking mechanism to be added as a modular component rather than redesigning the entire housing structure.
Solution Approach 2:
The locking member combines multiple functions: it locks the sleeve in place to prevent accidental actuation, and it can be disengaged by separating the casing parts. By merging the locking function with the existing separable casing structure, the patent avoids adding independent complex locking mechanisms while achieving reliable accidental actuation prevention.
Data Source
AI summary
A medicament delivery device including a housing for receiving a syringe, the housing having first and second casing parts separably attachable to one another. The device further includes a sleeve receivable within the housing and including a tubular wall having an inner surface delimiting a bore and an opposing outer surface. A locking member is receivable within the second casing part such that the locking member is axially movable between first and second axial positions relative to the second casing part. In the first axial position the locking member is engageable with the outer surface to inhibit an axial movement of the sleeve relative to the first casing part. In the second axial position the locking member is disengageable from the outer surface. The device, in one or more embodiments, includes an application as an autoinjector.