Pen Needle Tip Assembly with Locking Mechanism
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Solution Overview
Problem
Existing pen needles lack effective mechanisms to prevent reuse and ensure safe handling, particularly in preventing user pricking during handling and disposal.
Innovation Solution
A pen needle tip assembly with a double-ended hollow metal needle mounted on a disk-shaped synthetic resin needle support, where a one-piece body with a front and rear portion covers both puncturing ends before and after use, and a locking mechanism prevents re-use by limiting axial movement during installation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pen needle is designed without a reuse prevention mechanism, then the device complexity is reduced and manufacturing cost is lowered, but the reliability and safety are worsened due to potential reuse and user pricking risks
Solution Approach 1:
The needle tip assembly is divided into distinct functional segments: a needle support component, a body component, and a locking mechanism. This segmentation allows each part to perform its specific function (support, cover, lock) while maintaining overall system reliability without excessive complexity.
Solution Approach 2:
The locking mechanism is pre-configured in the needle tip assembly before use. The locking protrusion and locking recess are positioned in advance to automatically engage during installation, preventing reuse without requiring additional user actions or complex external mechanisms.
2Reliability
If a pen needle includes a locking mechanism to prevent reuse, then the reliability is improved, but the ease of operation is worsened due to additional steps in installation and removal
Solution Approach 1:
The locking mechanism operates automatically through self-service action. During installation, the needle support is inserted into the body and the locking protrusion automatically engages with the locking recess without user intervention. During removal, the same mechanism automatically disengages, eliminating the need for additional user steps.
Solution Approach 2:
The locking and unlocking actions occur rapidly during the installation and removal processes. The tapered surfaces of the locking mechanism allow for quick engagement and disengagement, skipping over potential operational delays while maintaining reliable reuse prevention.
3Reliability
If the body axially moves relative to the needle support during removal, then the locking mechanism effectively prevents reuse, but the manufacturing precision requirements increase to ensure proper alignment and engagement
Solution Approach 1:
The locking mechanism incorporates dynamic elements including tapered surfaces and movable components that adapt during assembly and removal. The tapered locking surfaces allow for self-alignment during axial movement, reducing the stringency of pre-assembly alignment requirements while maintaining effective locking engagement.
Solution Approach 2:
The needle tip assembly uses composite construction with a needle support made of synthetic resin and a metal needle. This composite approach allows for optimized material properties in each component, enabling the locking mechanism to achieve reliable engagement with moderate manufacturing tolerances through material compliance and design flexibility.
Data Source
AI summary
A needle tip assembly for a pre-loaded syringe or a pen needle injection device, including a needle with a first puncturing end projecting from a front side of a needle support and a second puncturing end projecting from a rear side of the needle support. A body sized to receive therein the needle support and the needle. The body including a front portion, a rear portion, and an overall axial length that is greater than an axial length of the needle. Prior to the needle tip assembly being in an installed condition on the pre-loaded syringe or pen needle injection device, the front portion covers the first puncturing end and the rear portion covers the second puncturing end. Prior to removal from the pre-loaded syringe or pen needle injection device, the body is at least axially movable to a position where the front portion covers the first puncturing end.