Needle Cover Assembly Rotational Removal Mechanism
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Solution Overview
Problem
Existing needle cover assemblies for medicament delivery devices often damage injection needles during removal due to twisting actions, and are complex in both use and manufacture, posing challenges for users with reduced hand dexterity.
Innovation Solution
A needle cover assembly featuring a manually operable member with a spinning attachment and a tubular shaped member with grip members, allowing for rotational movement without axial rotation, thereby reducing the risk of needle damage and simplifying the removal process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RNS is pushed onto the syringe neck with a resilient inner cap to ensure a tight grip and good seal, then the seal and grip are improved, but the difficulty of removing the RNS increases
Solution Approach 1:
The device is divided into separate functional components: the RNS with resilient cap remains sealed on the syringe, while a separate cap assembly with threaded engagement provides the removal mechanism. This segmentation allows the seal to remain intact while enabling easy removal through threaded rotation of the cap assembly.
2Ease of operation
If conventional RNS removal devices are used that twist or rotate the whole assembly including the RNS and resilient inner cap, then the removal process is aided, but the injection needle is easily damaged or bent
Solution Approach 1:
The harmful twisting action is extracted from the removal process by separating the rotation function into a dedicated cap assembly that engages with the RNS through threaded connection. This allows rotation to occur at the cap assembly level rather than twisting the entire RNS-needle assembly, preventing needle damage while maintaining removal assistance.
Solution Approach 2:
The cap assembly acts as an intermediary component between the user's manual operation and the RNS. It provides a threaded engagement mechanism that converts rotational motion into controlled linear motion for RNS removal, mediating the force application to prevent direct twisting of the needle.
3Object-affected harmful factors
If a threaded engagement mechanism is used between the cap assembly and RNS to convert rotational movement into linear movement, then the removal process is controlled and needle damage is reduced, but the device complexity increases
Solution Approach 1:
The cap assembly serves multiple functions: it provides the threaded engagement for controlled removal, acts as a grip surface for user operation, and serves as a protective cover during storage. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Data Source
AI summary
A needle cover assembly includes a manually operable member; a rigid needle shield (RNS) provided with an internally arranged resilient cap, in turn arranged to house and protect an injection needle; and a RNS remover assembly including a tubular shaped member surrounding the RNS, in which the tubular shaped member is arranged with at least one grip member capable of gripping the RNS in order to remove the RNS. The RNS remover assembly further includes a spinning attachment member having a distal end fixedly attached to the tubular shaped member and a proximal end rotatably attached to the manually operable member such that the manually operable member can be freely turned in relation to the RNS remover assembly but is locked in an axial direction.