Injection Cap Assembly for Combined Needle Shield Removal
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Solution Overview
Problem
Conventional injection devices require separate removal of the cap and needle shield, which can be difficult for infirm patients due to the small size of the needle shield, making it hard to handle.
Innovation Solution
A cap design with an inner member that slides within an outer member, featuring cooperating locking portions and clamping elements, allowing the cap and needle shield to be removed together, simplifying the process for patients with reduced strength or dexterity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cap and needle shield are designed to be removed separately, then each component can be individually secured, but the removal process becomes difficult for infirm patients due to the small size of the needle shield
Solution Approach 1:
The patent combines the cap and needle shield into a single integrated assembly where the needle shield is received within the cap. The inner member of the cap includes clamping elements that engage with the needle shield, allowing both components to be removed together as one unit. This merging eliminates the difficulty of handling the small needle shield separately while maintaining individual component functions.
Solution Approach 2:
The needle shield is nested within the cap structure, with the cap's inner member containing the needle shield. The inner member slides within the outer member, and the clamping elements on the inner member engage with the needle shield, creating a nested configuration where the smaller component (needle shield) is housed within the larger component (cap).
2Reliability
If the cap uses a complex locking mechanism to secure the needle shield, then the engagement is reliable, but the assembly process becomes more difficult
Solution Approach 1:
The inner member is designed to slide dynamically within the outer member along the axial direction. The clamping elements on the inner member dynamically engage with the needle shield during the sliding motion, providing reliable securing without requiring complex static locking mechanisms. The dynamic sliding action simplifies assembly while maintaining engagement reliability.
3Strength
If the cap is designed to hold the needle shield firmly, then the needle shield is securely retained, but the syringe glass may break due to excessive force on the flange
Solution Approach 1:
The clamping elements are positioned to apply holding force locally and specifically to the needle shield body, while deliberately avoiding contact with the syringe flange area. This localized application of force ensures strong retention of the needle shield without transmitting excessive force to the syringe glass flange, preventing breakage.
Data Source
AI summary
A cap for an injection device includes an outer member and an inner member slidably received within the outer member and moveable between a first position and a second position; cooperating locking portions on the inner and outer members configured to secure the inner member relative to the outer member once moved into the second position; a clamping element extending inwardly from an arm of the inner member or a contact surface of the outer member; wherein, the cap is configured such that as the inner member is moved to the second position, the arm engages the contact surface causing the clamping element to move inwards to engage a body when disposed within the cap, and the cooperating locking portions engage and retain the inner member in the second position.