Reusable Autoinjector Locking Mechanism for Secure Syringe Coupling
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Solution Overview
Problem
Existing autoinjectors, particularly reusable ones, face challenges in providing a reliable and efficient mechanism for connecting the syringe unit to the drive unit, leading to potential unintentional separation and increased waste due to disposable components like batteries and electronics.
Innovation Solution
A safety mechanism with a movable arm that can transition between locking and release positions via a trigger member's longitudinal movement, ensuring secure attachment and detachment of the syringe unit to the drive unit, utilizing a cam control for precise motion guidance and potentially incorporating an electric motor for automated operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a reusable drive unit with disposable syringe unit is used, then resource waste is reduced and cost is decreased, but the connection reliability between units deteriorates leading to potential unintentional separation
Solution Approach 1:
The autoinjector is divided into two separable units: a reusable drive unit and a disposable syringe unit. This segmentation allows the expensive electronic components to be reused while only the contaminated syringe portion is discarded, reducing resource waste and cost.
Solution Approach 2:
The connection between the drive unit and syringe unit is made dynamically controllable through a trigger member that can switch the arm between locked and unlocked positions. This dynamic connection ensures reliability during use while allowing intentional separation when needed, preventing unintentional separation through the locked state.
2Reliability
If a secure locking mechanism is implemented, then connection reliability is improved, but device complexity increases
Solution Approach 1:
The spring member automatically engages the arm with the syringe unit's flange when the trigger member is in the locked position, creating a self-securing connection. The mechanism uses the spring's inherent elastic force to maintain the locked state without requiring additional active components or complex control systems.
Solution Approach 2:
The arm acts as an intermediary element between the trigger member and the syringe unit's flange. It translates the trigger member's linear movement into radial locking motion, simplifying the overall mechanism by using a single intermediate component rather than multiple complex linkages.
3Reliability
If a movable arm locking mechanism is used, then unintentional separation is prevented, but the ease of operation for attachment and detachment deteriorates
Solution Approach 1:
The manual manipulation of multiple small components is replaced by a single linear push/pull motion of the trigger member. The spring member provides automatic engagement force, eliminating the need for users to manually tighten or secure the connection, thereby simplifying operation while maintaining reliability.
Data Source
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AI summary
The present invention relates to a safety mechanism for a drug delivery device (1). The safety mechanism comprising a reservoir unit (2) adapted to hold a reservoir (5) and a drive unit (3) releasably attachable to the reservoir unit (2). The drive unit (3) comprises a housing (10) defining a longitudinal axis, a drive (91) arranged inside the housing for driving a plunger rod (40) and a movable arm (70) that can be in a radially inner locking position, in which the reservoir unit (2) is locked relative to the drive unit (3) and wherein the arm (70) can be in a radially outer release position in which the reservoir unit (2) is released from the arm (70). The mechanism further comprises a trigger member (50) movable along the longitudinal adapted to move the arm (70) between the release position and the locking position.