Catheter Locking Assembly With Cam Arm
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Solution Overview
Problem
Existing drainage catheters face issues with accidental removal and potential infections due to bulky locking mechanisms, which prevent their use with smaller access sheaths.
Innovation Solution
A locking assembly with a cylindrical connector and curved locking arm, featuring a sealing element and interference fit, designed to fit within a 30 Fr access sheath, secures the tension member between the locking arm and connector, preventing disengagement and fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lockable connector with resilient material sleeve is used to secure the tension member, then the catheter can be locked into a loop configuration to prevent accidental removal, but the connector becomes bulky and cannot be used with smaller access sheaths
Solution Approach 1:
The locking mechanism is divided into separate functional components: a locking arm with cam surface, a connector with defined geometry, and a tension member. This segmentation allows each component to be optimized independently, resulting in a more compact overall structure that fits within smaller access sheaths while maintaining reliable locking functionality.
Solution Approach 2:
Instead of using a resilient sleeve that expands to lock (which increases volume), the invention uses a rigid locking arm with a cam surface that leverages mechanical advantage through geometric arrangement. The locking action is achieved through the cam surface engaging with the connector's geometry, inverting the approach from compliant material-based locking to rigid geometry-based locking.
2Reliability
If a bulky lockable connector is used to prevent catheter disengagement, then the catheter remains securely in place, but the device becomes uncomfortable for patients and requires larger access sheaths
Solution Approach 1:
The locking mechanism is divided into separate functional components: a locking arm with cam surface, a connector with defined geometry, and a tension member. This segmentation allows each component to be optimized independently, resulting in a more compact overall structure that fits within smaller access sheaths while maintaining reliable locking functionality.
Solution Approach 2:
The invention changes the geometric parameters of the locking components, specifically using a cam surface with optimized curvature and angle, and a connector with precisely defined internal geometry. These parameter changes enable a compact design that reduces the overall size of the locking assembly, improving patient comfort and enabling use with smaller access sheaths while maintaining secure catheter retention.
3Ease of operation
If the locking arm is pivotably attached to the connector, then the locking mechanism can transition between locked and unlocked positions, but additional components increase the overall device complexity
Solution Approach 1:
The locking arm is integrated with the connector through a pivot attachment, merging two components into a closely coupled assembly. The pivot pin serves dual functions: attaching the locking arm to the connector and serving as the rotation axis. This merging reduces the number of separate parts and simplifies the overall structure while maintaining the ability to transition between locked and unlocked positions.
Solution Approach 2:
The pivot pin serves multiple functions: it attaches the locking arm to the connector, provides the rotation axis for locking/unlocking transitions, and may serve as a sealing surface. This multi-functionality reduces the need for additional components, simplifying the overall device structure while maintaining operational capability.
Data Source
Figure 1~2
Figure 3~7
Figure 3A~5A
AI summary
A drainage catheter includes an elongated tubular member, a locking assembly engaged with a proximal end of the tubular member, and a tension member for drawing a distal end of the tubular member into a desired configuration. The locking assembly includes a connector, a locking arm, and a locking mechanism. The connector has an exterior surface profile that corresponds with an interior surface profile of the locking arm. The locking arm is pivotably attached to the connector to enable pivoting movement of the locking arm between an unlocked position and a locked position whereby the tension member is secured between the locking arm and the connector when the arm is in the locked position. The locking assembly may alternatively comprise a connector and a sliding sleeve or a connector having a clamping element disposed therein.