Autoinjector Actuator Sleeve Spring Locking Mechanism
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Solution Overview
Problem
Existing autoinjectors face issues with accidental triggering during transport or storage, difficulty in use for elderly or handicapped individuals, and the need for reliable needle safety mechanisms that degrade over time, leading to potential injuries and increased manufacturing costs.
Innovation Solution
An autoinjector design featuring a movable actuator sleeve with a spring mechanism, a removable cap that relieves stress on the flexible tab, and a dual-lock system using a guide profile and flexible tab to ensure secure triggering and needle safety, while being simple and inexpensive to manufacture and assemble.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reliable locking means are included to prevent accidental triggering, then safety is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is divided into two independent locks: a first lock that prevents movement of the actuator sleeve from its first position, and a second lock that prevents movement from its second position. This segmentation allows each lock to be simple and reliable without requiring a complex integrated system.
Solution Approach 2:
The flexible tab is pre-configured with a breaking point that fails under excessive force, automatically releasing the first lock if someone attempts to force the actuator sleeve. This preliminary safety feature prevents accidental triggering while maintaining simplicity.
2Reliability
If a needle safety device is included to prevent injury, then safety is improved, but device complexity increases
Solution Approach 1:
The actuator sleeve itself serves as the needle safety device. When the actuator sleeve moves to its second position, it automatically covers and retracts the needle, eliminating the need for a separate safety mechanism. This self-service approach maintains safety while minimizing complexity.
Solution Approach 2:
The actuator sleeve combines multiple functions: it drives the piston for injection, positions the needle during injection, and serves as the safety device by covering the needle after injection. This merging of functions reduces overall device complexity while maintaining reliable safety.
3Ease of manufacture
If the autoinjector is designed for single use, then manufacturing cost is reduced, but reliability of components degrades over storage time
Solution Approach 1:
The autoinjector is designed as a disposable single-use device, which simplifies manufacturing and eliminates the need for complex maintenance or sterilization systems. The simple structure with fewer components maintains reliability over storage time while keeping manufacturing costs low.
Solution Approach 2:
The flexible tab is designed with specific material properties and a predetermined breaking point that ensures reliable failure under excessive force. The spring is designed with specific force characteristics that maintain locking reliability throughout the storage period. These parameter optimizations ensure reliability while keeping the device simple and inexpensive to manufacture.
4Reliability
If the autoinjector requires precise actuation to function properly, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The actuator sleeve is designed to move freely between its first and second positions without requiring precise positioning or complex coordination. The user simply needs to push the actuator sleeve, and the spring-loaded locking mechanism and flexible tab automatically manage the transitions, making operation easy while maintaining reliability.
Solution Approach 2:
The locking mechanism and flexible tab automatically manage the actuator sleeve's positioning and safety functions without requiring precise user input. The system self-adjusts and self-locks, reducing the skill and precision needed for operation while ensuring proper function.
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 autoinjector provides reliable and safe operation, preventing accidental triggering and needle exposure, maintaining functionality over long storage periods, and simplifying user interaction, while reducing manufacturing costs through a robust and easy-to-assemble design.
Implementation Method 1
said actuator sleeve being urged towards said projecting positions by a spring
Implementation Method 2
one of said actuator sleeve and said body includes a flexible tab that is adapted to deform sideways and/or radially relative to said actuator sleeve and/or relative to said body when said actuator sleeve is moved
Data Source
AI summary
An autoinjector comprising a body (1) that is adapted to receive a reservoir (S), said reservoir (S) containing fluid and including a piston (P) and a needle (A), such as a pre-filled syringe, said autoinjector further comprising an actuator sleeve (10) that is movable relative to said body (1) between projecting positions in which said actuator sleeve (10) projects out from said body (1) at least in part, and an actuated position in which said actuator sleeve (10) is moved axially into said body (1), said actuator sleeve (10) being in a first projecting position before actuation of the autoinjector, and in a second projecting position after actuation of the autoinjector; said actuator sleeve (10) being urged towards said projecting positions by a spring (9), said autoinjector including a removable cap (20) that is fastened to said body (1) before the autoinjector is used, said removable cap (20), when it is fastened to said body (1), moving said actuator sleeve (10) axially relative to said first projecting position through a distance (d) into said body (1), against the force of said spring (9), such that when said removable cap (20) is removed from said body (1), said spring (9) returns said into said first projecting position.