Safety Cannula Trigger Mechanism for Frictionless Pullback
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Solution Overview
Problem
Existing safety cannula arrangements often cause discomfort or pain to patients due to unintentional movements or friction during the pullback mechanism, and they can be complex in design, leading to accidental triggering and impaired pullback movements.
Innovation Solution
A safety cannula assembly with a trigger mechanism located on the main body, featuring trigger members and locking elements arranged on opposite sides of the longitudinal axis, allowing for a radially inward pressure to move the locking element radially outward, facilitating a clear space for the pullback movement without manual manipulation of the sliding body, thus minimizing patient discomfort and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sliding body is manually manipulated to perform pullback movement, then the cannula can be moved into the main body, but this causes unintentional movements or forces on the cannula tip that are uncomfortable or painful for the patient
Solution Approach 1:
The sliding body is equipped with an automatic pullback mechanism that autonomously moves the cannula into the main body after use. The spring element stores energy during insertion and automatically releases it to perform the pullback movement without requiring manual manipulation, thereby eliminating unintended forces on the patient's tissue.
2Ease of operation
If the proximal end of the sliding body is greatly enlarged to accommodate a trigger mechanism, then the trigger can be operated from outside, but this impairs the pullback movement due to skin contact and induced friction forces
Solution Approach 1:
The trigger mechanism is extracted from the sliding body and relocated to the main body. This allows the sliding body to maintain a slender, uniform cross-section throughout its length, preventing skin contact and friction during the automatic pullback movement, while still enabling external operation of the trigger through the main body.
3Device complexity
If the locking elements are arranged close to the longitudinal axis for compact design, then the device is more compact, but the pullback movement can be impeded by skin contact and friction
Solution Approach 1:
The locking elements are integrated into the trigger mechanism located in the main body, allowing the sliding body itself to remain slender and uniform. The locking and triggering functions are performed through the main body structure, eliminating the need for enlarged sections on the sliding body that would contact skin and create friction.
4Ease of operation
If the trigger mechanism is arranged on the sliding body, then direct control of the sliding body is achieved, but this requires manual manipulation that can cause unintentional movements on the patient
Solution Approach 1:
The sliding body performs the pullback action automatically through its integrated spring element without requiring manual manipulation. The trigger mechanism in the main body simply initiates this autonomous process by releasing the locking elements, eliminating the risk of unintentional movements caused by manual handling during the critical pullback phase.
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 enables a smooth, unimpeded pullback movement of the cannula, reducing patient trauma and simplifying the cannula's operation, while maintaining a slender and intuitive design that prevents unintentional contact with the skin, thus enhancing safety and ease of use.
Implementation Method 1
an actuation element configured to cause the sliding body to perform pullback movement from the operating position into the safety position; a spring element that either store mechanical energy in the form of a coil spring
Implementation Method 2
at least one locking element displaceable from a locking position where the locking element engages the sliding body and locks the sliding body in the operating position
Implementation Method 3
allowing for a radially inward pressure to move the locking element radially outward, facilitating a clear space for the pullback movement
Data Source
AI summary
A safety cannula assembly, comprising a cannula configured to puncture human or animal tissue, wherein a distal end section of the cannula includes a tip; a sliding body including a distal end section connected with the cannula and a proximal end section connected with a flexible tube, wherein a flow connection between the tip of the cannula and a proximal end of the flexible tube runs through the sliding body; a main body including an interior space with the sliding body movably supported in the interior space; an actuation element arranged between the main body and the sliding body and configured to displace the sliding body from an operating position where the tip of the cannula is located outside the main body to a safety position where the tip of the cannula is arranged inside the main body.