Needle Protection Device With Folded Outer Edge Seal
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Solution Overview
Problem
Existing needle protection devices face issues such as accidental removal before use, difficulty in ensuring a leak-tight seal, complex and costly manufacturing, and inadequate prevention of needle injury after use.
Innovation Solution
A needle protection device with a flexible inner body and rigid outer body, featuring a radial projection and snap-fastening mechanism, which ensures a leak-tight seal and easy assembly, includes a breakable bridge for a first-use indicator and protective flaps to prevent accidental pricking, with the outer body's axial end edge folded down to secure the inner body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle protection device with flexible inner body and rigid outer body is used, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The needle protection device is divided into two functional segments: a flexible inner body for sealing and a rigid outer body for structural support and attachment. This segmentation allows each component to be optimized for its specific function, improving overall sealing reliability while maintaining manageable complexity through modular design.
Solution Approach 2:
The flexible inner body is nested within the rigid outer body, with the inner body positioned inside the outer body's cavity. This nested configuration allows the sealing element to be protected and pre-positioned within the structural housing, ensuring proper alignment and sealing contact without requiring additional complex assembly mechanisms.
2Reliability
If manufacturing and assembling the needle guard with separate inner and outer bodies is done, then sealing performance is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The device is segmented into manufacturable components that can be produced using standard molding processes for both thermoplastic elastomers (inner body) and rigid plastics (outer body). This segmentation enables independent optimization of manufacturing processes for each material type, reducing overall manufacturing complexity despite the multi-component design.
Solution Approach 2:
The attachment mechanism combines multiple functions: the radially outwardly extending attachment element on the inner body integrates with the outer body's attachment feature to provide both mechanical retention and sealing contact. This merging of attachment and sealing functions into a single integrated mechanism reduces the number of separate components and assembly steps required.
3Ease of manufacture
If the axial end edge of the outer body is folded down on the inner body to fasten it, then assembly simplicity is improved, but structural complexity increases
Solution Approach 1:
The axial end edge of the outer body is pre-formed with a folded-down configuration during the molding process, creating a ready-to-engage attachment structure. This preliminary formation of the folding feature eliminates the need for post-assembly folding operations, simplifying the assembly process while the resulting interlocked structure provides robust mechanical retention.
Solution Approach 2:
The folding mechanism replaces traditional mechanical fastening systems such as screws, clips, or adhesives. By using the folded edge to create a mechanical interlock through geometric constraint rather than additional fastening components, the design achieves secure attachment with simpler overall structure and fewer parts.
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 solution provides a reliable, easy-to-manufacture needle protection device that ensures a secure seal before use, indicates if the seal is broken, and prevents accidental needle exposure, while being simple to assemble and use.
Implementation Method 1
said axial end edge of said outer body being folded down on said inner body so as to fasten said inner body in said outer body
Implementation Method 2
said radial projection in abutment against said radial shoulder
Implementation Method 3
an outer body that is made of material that is substantially rigid... said outer body co-operating with said injection device so as to fasten said protection device on said injection device
Data Source
AI summary
A fluid injection device having a syringe body, a needle, and a needle protection device. The protection device includes a substantially flexible or deformable inner body and a substantially rigid outer body. The inner body closes a dispenser orifice of the needle, and co-operates with the syringe body in a leaktight manner, and the outer body fastens the protection device on the syringe body. The inner body includes a radial projection, and the outer body includes a radial shoulder and an axial end edge that defines a top axial opening. The inner body is inserted in the outer body, through the top axial opening, with the radial projection in abutment against the radial shoulder, the axial end edge of the outer body folded down on the inner body so as to fasten the inner body in the outer body.