Injection Needle Shield With Variable-Height Retention Bump
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Solution Overview
Problem
Existing active safety devices for injection devices require a high and variable activation force to move the needle cover from the retracted to the extended position, posing a challenge for users.
Innovation Solution
A safety device with a tubular body and needle cover that includes a retainer and a bump with a progressively decreasing height, along with chamfers and other design features, to distribute the activation force and reduce its variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional active safety device uses a uniform bump structure to retain the needle cover, then the needle cover can be held in the retracted position, but the activation force required to move the needle cover becomes high and variable
Solution Approach 1:
The bump structure is designed with non-uniform height along its circumferential length, creating zones of different retention strength. The higher portion provides strong retention while the lower portion facilitates easier activation, allowing the needle cover to be held reliably during use but released with reduced activation force.
Solution Approach 2:
The bump is segmented into distinct height zones (higher portion and lower portion) that perform different functions. This segmentation allows the single bump structure to provide both strong retention during the retracted position and reduced resistance during activation, eliminating the need for multiple separate components.
2Reliability
If the bump height is increased to improve needle cover retention, then the needle cover is held more securely, but the activation force required to move the needle cover increases
Solution Approach 1:
Rather than uniformly increasing bump height throughout, the invention applies increased height only in specific zones where retention is needed. The higher portion of the bump provides enhanced retention security, while the lower portion maintains acceptable activation force levels, resolving the trade-off between retention strength and activation ease.
Data Source
AI summary
The safety device includes a tubular body extending along a longitudinal axis. The tubular body is configured to receive the medical container, a needle cover movable relative to said body between a retracted position, and an extended position in which the needle cover distally extends from the retracted position in order to shield the injection needle after activation of the safety device, a release element configured to move the needle cover from the retracted to the extended position after activation of the safety device, and a retainer for maintaining the release element in a compressed condition when the needle cover is in the retracted position. The retainer is configured to transmit a user's activation force to the needle cover once the injection operation is completed. The needle cover includes a distal abutment surface, said distal abutment surface abutting against a proximal abutment surface of a bump protruding from the body in the retracted position of the needle cover. The bump of the body has a first end, an opposite second end, and a decreasing height from said second end to said first end.