Stylet Safety Shield Locking Mechanism for Biopsy Needles
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Solution Overview
Problem
Conventional stylet safety shields in bone needle assemblies often automatically lock, making it difficult to re-expose the tip for reuse and increasing the risk of injury during re-exposure.
Innovation Solution
A biopsy needle assembly with a safety shield featuring a locking mechanism that can be configured between unlocked and locked states, allowing the shield to move with the stylet when disconnected from the cannula, and a shield release device to facilitate easy retraction and exposure of the stylet tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stylet safety shield automatically locks over the stylet tip, then the safety and contamination protection is improved, but the ease of re-exposing the tip for reuse deteriorates
Solution Approach 1:
The safety shield transitions from a static locked position to a dynamic system with controlled movement. The shield can be manually repositioned along the stylet shaft using a groove and protrusion mechanism, allowing it to move between covering the tip and exposing it, thus resolving the contradiction between automatic locking safety and ease of re-exposure.
Solution Approach 2:
The safety shield is divided into separable components: the shield body, the locking mechanism, and the repositioning groove. This segmentation allows the shield to be independently manipulated along the stylet shaft, enabling users to re-expose the tip by moving the shield to a different position in the groove, while maintaining automatic locking functionality.
2Object-affected harmful factors
If the stylet safety shield automatically locks, then the prevention of contamination is improved, but the risk of injury during re-exposure increases
Solution Approach 1:
The shield is pre-positioned in a groove along the stylet shaft that allows controlled movement. Before re-exposure is needed, the user can manually move the shield to expose the tip, and the locking mechanism is designed to engage at specific positions in the groove, preventing accidental movement during use but allowing intentional re-exposure when needed.
Solution Approach 2:
The groove in the stylet shaft acts as an intermediary structure between the shield and the stylet tip. It provides a controlled path for shield movement, allowing the shield to be repositioned to expose the tip while preventing uncontrolled movement that could cause injury. The groove mediates between the locked safety position and the exposed tip position.
3Ease of operation
If the stylet is disconnected from the cannula, then the ease of removing the stylet is improved, but the control over shield positioning deteriorates
Solution Approach 1:
The shield positioning system is self-contained on the stylet assembly. The groove and locking mechanism are integrated into the stylet and shield components, allowing the shield to be repositioned and locked independently of the cannula connection status. This self-service mechanism maintains positioning control even when the stylet is disconnected from the cannula.
Data Source
AI summary
A bone needle assembly has a cannula and a stylet including a shaft received in a cannula shaft. A stylet safety shield is carried by the stylet to cover a sharp tip of the stylet shaft when removed from the cannula shaft after the bone is penetrated. The stylet includes a shield release device that moves the shield somewhat out of a handle member of the stylet when the stylet is released from the cannula, so that the safety shield can be more easily grasped.