Balloon Catheter Retractable Sheath Locking Mechanism
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Solution Overview
Problem
Existing balloon catheters lack a mechanism to quickly and easily adjust the length of the inflated balloon portion and securely retain the sheath in a desired position during surgical procedures, such as percutaneous transluminal angioplasty.
Innovation Solution
The balloon catheter features an adjustable sheath assembly with a clamp mechanism that allows for selective adjustment of the balloon length and a locking mechanism to maintain the sheath in position, utilizing a combination of a housing with actuator arms, springs, and push buttons to control axial movement, along with optional radiopaque markers and a tapered insertion tip for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a retractable sheath is used to adjust balloon length, then the ability to adjust balloon length is improved, but the mechanism complexity increases
Solution Approach 1:
The sheath is nested within the catheter shaft, with the sheath having an inner surface defining a lumen through which the catheter shaft passes. This nesting arrangement allows the sheath to be retracted along the shaft to expose different lengths of the balloon without requiring separate adjustment mechanisms for each component.
Solution Approach 2:
The sheath is designed to be movable relative to the catheter shaft, transitioning between retracted and extended positions. This dynamic configuration allows the operator to adjust the exposed balloon length by moving the sheath axially, providing adaptability while maintaining a relatively simple structural design.
2Stability of the object's composition
If a locking mechanism is added to retain sheath position, then the stability of sheath position is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism utilizes the inflation pressure of the balloon itself to engage and lock the sheath in position. When the balloon is inflated, the pressure causes the sheath to be pushed against the catheter shaft or engagement features, automatically securing the sheath without requiring separate locking actuators or complex control systems.
Solution Approach 2:
The balloon serves as an intermediary between the inflation system and the sheath locking function. The inflation pressure transmitted through the balloon acts as the mediating force that secures the sheath position, eliminating the need for dedicated locking mechanisms while maintaining stability.
3Speed
If the sheath is made retractable for quick adjustment, then the speed of adjustment is improved, but the reliability of sealing may worsen
Solution Approach 1:
The sheath is constructed as a flexible, movable component that can be retracted smoothly along the catheter shaft. This flexible design allows for quick adjustment while maintaining the ability to form reliable seals at the interface between the sheath and catheter, preventing fluid leakage during retraction and extension movements.
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
Enables quick adjustment and secure retention of the balloon length, facilitating precise placement and minimizing drug elution during insertion, while maintaining a watertight seal to prevent fluid entry and ensure effective delivery of drugs and stents.
Implementation Method 1
a spring positioned within the housing and engaging the actuator arm
Implementation Method 2
a tapered insertion tip
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A balloon catheter has a retractable sheath that can quickly and easily adjust the length of the inflated portion of the balloon and a locking mechanism for selectively retaining the sheath in the desired position for use. The balloon catheter assembly includes an inner member and an outer member that is disposed about the inner member. The outer member includes one or more inflatable balloons. A sheath is disposed about the outer member for movement relative to the balloon so as to selectively expose some or all of the balloon for inflation. Lastly, the balloon catheter assembly includes a clamp for selectively securing the sheath at a desired position relative to the balloon.