Injector Pen Nut Retention for Sub-Assembly Transport
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injector pens require complex assembly processes and secure coupling methods to integrate the dose selector housing and cartridge housing, which complicates manufacturing, transport, and final assembly, especially when drugs have limited shelf-life or specific storage requirements.
Innovation Solution
A sub-assembly method for injector pens that involves a nut with alignment arms and clips to securely engage the cartridge housing with the dose selector housing, allowing for easy assembly and disassembly, and enabling the pens to be transported and stored in a ready-to-use state without the drug cartridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the injector pen is assembled with the drug cartridge during initial manufacture, then the pen is ready for immediate use, but the storage and distribution become complicated due to limited shelf-life and storage requirements of certain drugs
Solution Approach 1:
The injector pen is divided into two separable components: the dose selector housing (without cartridge) and the drug cartridge. The dose selector housing can be manufactured, distributed, and stored independently without drug storage constraints. The drug cartridge is separately prepared and attached only when needed, enabling flexible distribution and storage while maintaining readiness for use.
2Reliability
If the injector pen uses a complex secure coupling method to integrate dose selector housing and cartridge housing, then the assembly is secure and reliable, but the manufacturing and final assembly processes become complicated
Solution Approach 1:
The coupling mechanism is segmented into modular components: alignment arms with alignment features on the dose selector housing, and corresponding alignment features on the cartridge housing. This modular segmentation enables simple yet reliable alignment and attachment during final assembly, reducing overall system complexity while maintaining secure integration.
Solution Approach 2:
The alignment arms and alignment features are pre-configured during manufacture of the dose selector housing and cartridge housing respectively. This preliminary preparation of alignment mechanisms ensures that final assembly is straightforward and reliable, eliminating the need for complex adjustment or alignment procedures during final assembly.
3Ease of manufacture
If the injector pen is designed for easy assembly and disassembly of the cartridge housing, then the final assembly process is simplified, but the coupling mechanism may become less secure
Solution Approach 1:
The coupling mechanism uses segmented alignment arms that can flex or move independently during assembly, allowing easy insertion of the cartridge housing. Once assembled, the alignment features interlock to provide secure coupling. This segmentation enables both easy assembly and strong coupling without compromise.
Solution Approach 2:
The alignment features may incorporate curved or tapered surfaces that guide the cartridge housing into proper alignment during insertion, facilitating easy assembly. Once engaged, the geometry of these curved surfaces creates mechanical interference that provides secure coupling strength, combining assembly ease with connection reliability.
Data Source
AI summary
An injector pen is provided that includes a cartridge housing 2, a dose selector housing 10 and a nut 18 for coupling the two housings 2,10 together. The dose selector housing 10 defines an intermediate axial position, where the nut 18 can be temporarily retained in the dose selector housing 10 to form a sub-assembly suitable for transport to a different location. During final assembly of the injector pen, the cartridge housing 2 securely engages with the nut 18 and displaces the nut 18 from the intermediate axial position to a final axial position.