Pen Needle Retractable Shield Locking Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pen needles lack effective mechanisms for automatic retraction and locking of needle shields, which can lead to accidental needle sticks and reuse.
Innovation Solution
A pen needle assembly with a retractable distal needle shield and a proximal needle shield, both equipped with locking mechanisms, which automatically retract and lock in place after use to prevent re-use and accidental needle sticks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retractable needle shield mechanism is added to prevent accidental needle sticks, then safety is improved, but device complexity increases
Solution Approach 1:
The needle shield is designed to automatically retract and lock using the mechanical energy from the needle's insertion and withdrawal movements itself, without requiring separate power sources or complex control systems. The spring-loaded mechanism self-activates based on the natural use cycle of the needle.
Solution Approach 2:
A spring-loaded intermediary mechanism is introduced between the needle shield and the hub to enable automatic retraction. This spring mechanism acts as a mediator that stores and releases mechanical energy to drive the shield's movement, simplifying the overall control system while maintaining safety functionality.
2Reliability
If a locking mechanism is added to prevent needle reuse, then safety is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is designed to automatically engage in the locked position before use, and the visual indicator is pre-positioned to show the initial state. This preliminary configuration ensures that no additional actions are needed to establish safety, and the system transitions automatically through its safety states during normal use.
Solution Approach 2:
A visual indicator mechanism is incorporated that changes its visible state (through movement or color change) to communicate the locking status to the user. This provides clear feedback about the safety state without requiring complex electronic displays or additional controls.
3Ease of operation
If automatic retraction mechanism is implemented, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The retraction mechanism is designed to automatically execute the retraction and locking actions based on the natural movements of needle insertion and withdrawal. The system uses the mechanical energy from these movements itself to drive the shield, eliminating the need for separate user actions or external power sources.
Solution Approach 2:
The needle shield operates in periodic cycles corresponding to the injection process: extended during storage, retracted during insertion and injection, and automatically returned to extended position after withdrawal. This periodic operation aligns with the natural rhythm of needle use, simplifying user interaction.
Data Source
AI summary
A pen needle (10) includes a hub (34) supporting a needle (28) and a distal needle shield (14) that can retract to expose the needle during injection and return to the extended position after use and locked in the extended position cover the needle. A proximal needle shield (16) moves to an extended position with respect to the hub (34) to cover a proximal end (34) of the needle. A spring (64) extends between the distal needle shield (14) and the proximal needle shield (16) to bias each needle shield to the respective extended position. A locking member (78) on the distal needle shield cooperates with the hub to lock the needle shields in the extended position. An indicator (94) in the hub engages and couples to the distal needle shield (14) when moved to the retracted position. The indicator (94) moves with the distal needle shield (14) to the extended position where the indicator is visible through the distal needle shield (14) indicating that the pen needle is no longer usable.