Autoinjector Needle Shield Removal Subassembly
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Solution Overview
Problem
Current medicament delivery devices face challenges in efficiently removing needle shields, particularly for patients requiring frequent injections and those administering viscous drugs, with existing solutions often involving costly materials like stainless steel.
Innovation Solution
A subassembly for a medicament delivery device comprising a syringe housing with separable parts and a cap design that uses flexible arms and ribs to facilitate easy removal of the shield member, allowing for cost-effective construction without stainless steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shield member removal mechanisms are used, then reliability of shield removal is improved, but device complexity and manufacturing cost increase due to use of stainless steel components
Solution Approach 1:
The patent applies this principle by replacing traditional stainless steel shield removal components with disposable plastic components. The cap and flexible arms are designed as single-use plastic components that are discarded after one use, eliminating the need for expensive stainless steel parts while maintaining functional reliability during the intended service life.
Solution Approach 2:
The patent changes the material parameter from stainless steel to plastic, and modifies the structural parameters by introducing flexible arms with specific geometries (protrusions, grooves, ribs) that enable reliable shield removal through elastic deformation and mechanical interlocking, rather than relying on rigid metal components.
2Strength
If stainless steel components are used for shield member removal, then strength and durability are improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive stainless steel components with inexpensive plastic components designed for single-use. The plastic cap and flexible arms provide sufficient strength for shield removal during the brief operational period, after which they are discarded, eliminating the need for costly metal manufacturing processes.
Solution Approach 2:
The patent changes the material parameter from stainless steel to plastic, and adjusts structural parameters (wall thickness, rib dimensions, flexible arm geometry) to provide adequate strength for shield removal while maintaining low manufacturing costs through injection molding processes.
3Ease of manufacture
If a simple cap design is used, then ease of manufacture is improved, but reliability of shield member removal deteriorates
Solution Approach 1:
The patent divides the cap into multiple functional segments: flexible arms with protrusions for engaging the shield, ribs for providing structural support and leverage, and a body portion for user gripping. This segmentation allows each element to be optimized for its specific function while remaining manufacturable through standard injection molding techniques.
Solution Approach 2:
The patent incorporates dynamic elements through the flexible arms that can elastically deform during the shield removal process. The flexible arms bend and flex to accommodate the shield's position and provide the necessary mechanical advantage for reliable removal, while returning to their original shape after use.
4Reliability
If flexible arms with engagement features are added to the cap, then shield member removal reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the cap component: the cap body provides user gripping, the flexible arms provide shield engagement and removal force, the ribs provide structural support and mechanical leverage, and the protrusions provide precise positioning. This merging of functions into a single integrated plastic component avoids the complexity of assembling multiple separate metal parts.
Solution Approach 2:
The cap is designed as a multi-functional component that performs multiple tasks: protecting the shield during storage, providing a gripping surface for users, engaging the shield for removal, and providing structural support throughout the process. This universal design reduces the overall number of components needed in the system.
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
Enables reliable and cost-efficient removal of the shield member, enhancing user safety and device usability by simplifying the process with a robust and efficient mechanical design.
Implementation Method 1
a flexible arm comprising a protrusion configured to engage with a proximally facing surface of the proximal syringe housing part
Implementation Method 2
the at least one flexible arm of the cap comprises a radial protrusion configured to engage with a distally facing surface of the proximal syringe housing part, wherein when the cap is disassembled from the syringe housing by moving the cap proximally relative the syringe housing, the engagement between the radial protrusion of the at least one flexible arm of the cap and the distally facing surface of the proximal syringe housing part causes the proximal syringe housing part to move proximally relative the distal syringe housing part
Data Source
AI summary
The present disclosure generally relates to medicament delivery devices such as autoinjectors, and particularly concerns a subassembly for removing a needle shield.