Pivoting Cannula Insertion Mechanism for Precise Needle Retraction
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Solution Overview
Problem
Conventional medical devices, such as on-body injectors, lack a simple structure, compact size, and precise insertion and retraction functions, making them difficult to operate effectively.
Innovation Solution
A medical insertion mechanism with a base, needle holder, cannula holder, pivoting assembly, lever, actuator, and driving component, allowing for precise control of needle and cannula insertion and retraction through a sliding and pivoting mechanism driven by an actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional on-body injectors are used, then basic injection function is provided, but structure complexity increases and compact size is not achieved
Solution Approach 1:
The needle holder and cannula holder are merged into a single integrated assembly that moves together during insertion. The pivoting assembly combines multiple functions (needle/cannula insertion, needle retraction) into one compact mechanism, reducing overall device complexity while maintaining compact size.
Solution Approach 2:
The needle is nested within the cannula during storage and insertion. The needle holder is positioned within the cannula holder assembly, allowing both components to occupy minimal space while maintaining full functionality. This nesting arrangement achieves compact size without sacrificing injection capability.
2Ease of operation
If conventional on-body injectors are used, then injection capability is provided, but ease of operation deteriorates
Solution Approach 1:
The mechanism transitions from a static stored state to dynamic operation through a single user action. The pivoting assembly rotates from a first position (needle and cannula retracted) through a second position (insertion) to a third position (needle retracted, cannula remaining). This dynamic motion sequence provides intuitive ease of operation while ensuring reliable insertion and retraction functions at each stage.
Solution Approach 2:
The lever acts as an intermediary between the user's manual input and the complex motion required for insertion and retraction. By applying force to the lever, the user indirectly controls the pivoting assembly, needle holder, and cannula holder movements, simplifying operation while maintaining precise control over the reliable insertion and retraction sequence.
3Manufacturing precision
If conventional on-body injectors are used, then basic function is provided, but precise insertion and retraction function is not achieved
Solution Approach 1:
The mechanism uses dynamic pivoting motion to achieve precise positioning at each stage. The pivoting assembly's rotation from first to second position ensures precise needle and cannula insertion, while rotation from second to third position precisely retracts the needle. This dynamic approach achieves manufacturing precision without requiring complex adjustment mechanisms.
Solution Approach 2:
The mechanical design incorporates inherent feedback through the pivoting assembly's geometry and the lever's position. As the pivoting assembly rotates, the lever naturally transitions between positions, providing tactile feedback to the user about the current state (insertion complete, retraction complete). This feedback mechanism ensures precise insertion and retraction functions without adding complex electronic or mechanical control systems.
Data Source
AI summary
A medical insertion mechanism is provided and includes a base, a needle holder slidably disposed on the base, a needle disposed on the needle holder, a cannula holder arranged at a position corresponding to the needle holder, a cannula disposed on the cannula holder, a pivoting assembly pivotally disposed on the base, a lever movably disposed on the base and movably engaged with the pivoting assembly, an actuator disposed on the base, and a driving component for driving the pivoting assembly to pivot when the actuator slides to disengage from the pivoting assembly. When the pivoting assembly pivots, the lever drives the needle holder to slide along an insertion direction and then along a retraction direction, so as to insert the cannula into the patient's body. Besides, a medical device having the aforementioned medical insertion mechanism is also provided.