Needle Magazine Cartridge Profile Reduction via Segmented Hub Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medication injection devices with disposable needle cartridges have a large profile and are prone to needle exposure and tilting, which can lead to leakage through the medication cartridge septum.
Innovation Solution
A cartridge design with reciprocating drive members and needle assemblies featuring a hub with a push surface and a movable second hub portion, allowing for low-profile configuration, reduced shifting, and resistance to tilting, utilizing a carousel with indexed notches for precise alignment and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the cartridge uses traditional needle assembly design with hubs and spanning segments, then the needle assemblies can be manufactured with standard processes, but the overall profile height of the injection device becomes larger than desired
Solution Approach 1:
The patent removes the spanning segment entirely from the needle assembly design. The needle is configured as two separate leg segments (first leg segment and second leg segment) that are positioned parallel to each other without requiring a connecting spanning segment. This extraction of the spanning segment directly reduces the cartridge profile height while maintaining needle functionality.
Solution Approach 2:
The needle is segmented into two separate leg segments (first leg segment and second leg segment) that function independently but work together for injection. This segmentation allows the needle to achieve the necessary structural integrity and flexibility without requiring the additional height of a spanning segment, thereby reducing the overall cartridge profile.
2Reliability
If the needle assemblies are held in a fixed position within the cartridge, then the cartridge structure is simpler, but the needles are prone to shifting and exposure during handling
Solution Approach 1:
The cartridge includes a carousel with indexed notches that are pre-configured to receive and secure needle assemblies at specific positions. The notches are designed with complementary shapes that engage with corresponding features on the needle assembly hubs, providing preliminary positioning and securing before use. This preliminary action prevents shifting and exposure during handling while maintaining a relatively simple cartridge structure.
3Reliability
If the needle assemblies use a single hub design, then the manufacturing process is simpler, but the assemblies are prone to tilting during injection which can cause leakage
Solution Approach 1:
The hub is divided into two distinct portions: a first hub portion that provides the base structure and a second hub portion that extends outward to receive the leg segments. This segmentation allows each portion to be optimized for its specific function - the first hub portion for structural support and the second hub portion for precise needle positioning - thereby preventing tilting during injection while maintaining manufacturing simplicity.
Solution Approach 2:
The second hub portion is specifically designed with a shape and orientation that complements the leg segments, providing localized support and alignment features. This local quality enhancement at the second hub portion ensures proper needle positioning and prevents tilting during injection, while the rest of the hub structure remains simple for easy manufacture.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A cartridge with injection needles for an injection device. The cartridge includes a plurality of injection needle assemblies, each including a hub and a needle having ends that face in a first direction. The cartridge also includes a needle assembly support defining a plurality of needle assembly accommodating cavities in which the injection needle assemblies are mounted to be shiftable in the first direction from a retracted position to an injection position, during which shifting a second hub portion moves relative to a first hub portion between a ready arrangement and a needle assembly lifting arrangement. The needle assembly support is loadable into the injection device to be movable therein to allow for separate operational alignment of each injection needle assembly with the drive member (320) of the injection device. The cartridge includes a hub having drive member engageable push and pull surface.