Safety Cannula Sliding Body Rotation Blocking and Stop Surface Design
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Solution Overview
Problem
Existing safety cannula assemblies often have complex designs that complicate the implementation of rotation blocking and end stop functions, which can lead to increased production complexity and potential user discomfort during handling.
Innovation Solution
A safety cannula assembly with a sliding body that includes a rotation blocking device and a separate stop surface, allowing for a simple configuration where the rotation blocking body can be offset from the locking elements, and a trigger mechanism that enables the sliding body to move from an operating position to a safety position without requiring elastic deformation, thereby preventing rotation and ensuring axial movability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking elements are used to secure the sliding body in the operating position, then the cannula is held securely for puncture, but the design becomes complex and production difficulty increases
Solution Approach 1:
The locking elements are integrated directly into the trigger mechanism components. The first and second trigger members incorporate locking elements as integral parts, eliminating the need for separate locking components. This merging reduces the overall number of parts and simplifies the design while maintaining reliable locking functionality during the puncture operation.
2Volume of moving object
If elastic deformation is required for the sliding body to move to safety position, then the mechanism can be compact, but user comfort decreases due to resistance during handling
Solution Approach 1:
The sliding body is designed with dynamic movement characteristics that allow smooth transition between operating and safety positions. The actuation element provides controlled movement without requiring significant elastic deformation, enabling easy user operation. The mechanism incorporates guide surfaces and minimal friction interfaces that facilitate smooth sliding motion while maintaining compact dimensions.
3Manufacturing precision
If rotation blocking is implemented through complex structural features, then cannula orientation is precisely controlled, but manufacturing complexity increases
Solution Approach 1:
The rotation blocking features utilize asymmetric geometries that are simple to manufacture. The first and second rotation blocking bodies have asymmetric shapes that naturally prevent rotation of the sliding body without requiring complex machining. These asymmetric features can be easily formed during injection molding or basic machining operations, maintaining manufacturing simplicity while achieving precise cannula orientation control.
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 simplifies the design, reduces production complexity, and enhances user ergonomics by maintaining a rigid sliding body configuration, improving handling and preventing unintentional cannula exposure, while maintaining precise cannula tip positioning.
Implementation Method 1
configured as spring element that either stores mechanical energy in the form of a coil spring
Implementation Method 2
stores mechanical energy in the form of a coil spring
Implementation Method 3
pressure energy like e.g. in a preloaded gas storage device
Data Source
AI summary
A safety cannula assembly, comprising: a cannula configured to puncture human or animal tissue, wherein the cannula includes a distal end portion including a tip; a sliding body including a distal end portion connected to the cannula and a proximal end portion connected to a flexible tube, wherein a flow connection extends through the sliding body between the tip of the cannula and a proximal end of the flexible tube; a main body in which the sliding body is displaceable from an operating position, where the tip is located outside the main body to a safety position, where the tip is located inside the main body, wherein a stop surface of the sliding body contacts a stop surface of the main body in the safety position, so that further axial displacement of the sliding body relative to the main body in the proximal direction is prevented.