Needle Protection Assembly with Integrated Locking Spring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing needle protection systems require high spring force to overcome deflecting members, leading to deformation of plastic parts, inaccurate injections, and increased complexity in manufacturing, while low-duty springs lack sufficient force to function properly.
Innovation Solution
A needle protection assembly with a low-duty spring that combines the functions of urging the needle shield into position and forming part of the locking system, eliminating the need to overcome friction forces, thereby reducing the force exerted on plastic parts and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high spring force is used to overcome deflecting members resistance, then the needle protection system can be triggered properly, but plastic parts deform and injection accuracy deteriorates
Solution Approach 1:
The locking system is segmented into multiple deflecting members (first deflecting member on needle shield, second deflecting member on needle hub) that can be engaged sequentially. This segmentation allows the spring force to be distributed across multiple engagement points rather than requiring one high-force engagement, reducing peak forces that cause deformation.
Solution Approach 2:
The solution introduces a longitudinal dimension to the locking mechanism by using a groove extending along the needle hub axis. The deflecting members engage at different longitudinal positions, allowing the needle shield to move progressively through the injection stroke while maintaining locked engagement, thereby reducing the force required at any single moment.
2Ease of operation
If high spring force is used to overcome deflecting members friction, then the needle shield can be displaced, but the spring force deforms plastic parts in storage position
Solution Approach 1:
The deflecting members are pre-positioned on the needle hub and needle shield before use. The groove is pre-formed on the needle hub surface. When the needle shield moves distally, the deflecting members automatically engage with the groove without requiring high force to create engagement features, reducing peak spring force requirements and preventing plastic deformation during storage.
3Reliability
If high spring force is used, then the needle protection system overcomes resistance, but the system becomes more complex and expensive
Solution Approach 1:
The locking and guiding functions are merged into a single integrated groove structure on the needle hub. The groove simultaneously serves as the engagement path for the deflecting members and as the guide for their movement. This eliminates the need for separate locking features and high-force springs, reducing overall system complexity while maintaining reliable locking functionality.
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 allows for easy triggering of the needle protection without deforming plastic parts, ensures accurate injection, and reduces manufacturing complexity, making the assembly easier to assemble and more environmentally friendly.
Implementation Method 1
first urging means located between said support and said needle shield, and tending to displace said needle shield from said in use position to said after use position
Data Source
AI summary
The application relates to a needle protection assembly (1) comprising a support (2), a needle shield (8), urging means (10) located between said support (2) and said needle shield (8), tending to displace said needle shield (8) distally over said needle (3), wherein the assembly comprises one abutment (5) provided on said support (2), receiving a locking element (10a), a part of said urging means being laterally movable with respect to said support (2) and forming part of said locking element (10a).