Needle Safety Device Segmented Locking Mechanism
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Solution Overview
Problem
Existing needle safety devices for medical injection devices cause injection area torsion and can be manually unlocked, allowing potential reuse or accidental contact with the cannula, which are undesirable for patient comfort and hygiene.
Innovation Solution
A needle safety device with a tubular protection element and separable locking parts that prevent accidental contact and reuse by using a spring element to bias the protection element away from the cannula and separating into locking parts that block return to the initial position, eliminating the need for a guide pin and reducing torsion during injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking means is provided to fix the sleeve after injection, then the cannula is permanently protected from contact, but the locking means can be manually released again allowing potential reuse
Solution Approach 1:
The locking means is segmented into a locking arm and a separate pin component. The pin is designed to be displaceable only in the initial state, allowing the locking arm to be manually positioned, but once locked, the pin prevents any manual release. This segmentation creates an irreversible locking mechanism that maintains reliability while limiting ease of operation after injection.
Solution Approach 2:
The pin is pre-configured in a position that allows manual manipulation of the locking arm during the initial state. After injection, the pin automatically displaces to a position that prevents any further manual manipulation. This preliminary action ensures that the ease of operation is available only when needed (before injection) and is automatically eliminated afterward to prevent reuse.
2Reliability
If the sleeve undergoes rotation during injection to effect locking, then the locking function is achieved, but the injection area experiences torsion causing patient discomfort
Solution Approach 1:
The locking mechanism transitions from a static rotational locking system to a dynamic linear displacement system. The pin moves linearly along the longitudinal axis during injection, engaging with the locking arm in its displaced position. This dynamic linear motion eliminates the harmful rotational torsion while maintaining the reliability of the locking function through the progressive engagement of the pin with the locking arm.
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 prevents accidental contact and reuse of the needle safety device, enhancing patient comfort by avoiding torsion and improving security against unintended reactivation.
Implementation Method 1
a spring element which biases the protection element in a distal direction relative to the hub portion
Data Source
AI summary
A needle safety device comprises (a) an elongated hub portion with a longitudinal axis that comprises a cannula, (b) a tubular protection element that is movable along the longitudinal axis relative to the hub portion, wherein the protection element comprises a contact surface for establishing pressure contact with an injection area, (c) a tubular separable element comprising at least two locking parts and (d) a spring element which biases the protection element such that the contact surface is further spaced apart from the hub portion along the longitudinal axis than the tip of the cannula. The protection element is configured to move into an injection position, wherein the separable element separates into the locking parts when the contact surface is released from contact with the injection area. The separated locking parts block the protection element from returning into the injection position when the protection element has moved to a final position.