Programmable Valve for Hydrocephalus Using Cam Surface and Helical Spring
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Solution Overview
Problem
Existing programmable valves for hydrocephalus treatment face issues with unstable regulation under strong magnetic fields and high standard deviation in pressure settings due to reliance on magnetic forces and cantilevered spring blades, which are difficult to manufacture precisely and uniformly.
Innovation Solution
A surgically implantable valve design featuring a helical spring and a rotor with a cam surface that adjusts the sealing ball's pressure without direct contact, using locking members with magnets that are kept in an operative position by springs for rotational locking, allowing precise control and unlocking in magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spring blade is used to press the sealing ball against the seat, then the valve opening pressure can be adjusted, but the manufacturing precision and uniformity are difficult to control due to cantilever structure requirements
Solution Approach 1:
The patent introduces a cam surface as an intermediary mechanism between the rotor and the sealing ball. Instead of directly pressing the ball with a spring blade, the cam surface converts rotational movement into controlled linear movement, providing a mechanical advantage that reduces the spring force required and simplifies manufacturing tolerances.
Solution Approach 2:
The patent replaces the direct cantilever spring blade mechanism with a cam-based mechanical system. The cam surface profile is designed to provide the necessary force variation, substituting the complex spring blade geometry with a simpler cam profile that is easier to manufacture with high precision.
2Ease of operation
If magnetic forces are used for rotational locking, then the valve can be adjusted to different positions, but the locking becomes unstable under strong magnetic fields such as in MRI exams
Solution Approach 1:
The patent introduces a cam surface as an intermediary mechanism between the rotor and the sealing ball. Instead of directly pressing the ball with a spring blade, the cam surface converts rotational movement into controlled linear movement, providing a mechanical advantage that reduces the spring force required and simplifies manufacturing tolerances.
Solution Approach 2:
The patent replaces the direct cantilever spring blade mechanism with a cam-based mechanical system. The cam surface profile is designed to provide the necessary force variation, substituting the complex spring blade geometry with a simpler cam profile that is easier to manufacture with high precision.
3Reliability
If indexing means are used for rotational locking, then the rotor can be stabilized in different positions, but the locking depends on the degree of interference between indexing means which may not be sufficient
Solution Approach 1:
The patent introduces a cam surface as an intermediary mechanism between the rotor and the sealing ball. Instead of directly pressing the ball with a spring blade, the cam surface converts rotational movement into controlled linear movement, providing a mechanical advantage that reduces the spring force required and simplifies manufacturing tolerances.
Solution Approach 2:
The patent replaces the direct cantilever spring blade mechanism with a cam-based mechanical system. The cam surface profile is designed to provide the necessary force variation, substituting the complex spring blade geometry with a simpler cam profile that is easier to manufacture with high precision.
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 valve achieves precise control of opening pressure with reduced standard deviation and maintains locking without magnetic forces, ensuring stability and ease of adjustment even in magnetic environments.
Implementation Method 1
arranged inside the inlet duct, between the sealing ball and a supporting ball which protrudes partially into the body, to cooperate with a cam surface of a rotor
Implementation Method 2
two cavities, in each one a locking member, carrying a magnet, is slidingly housed, to be linearly displaced between an operative position and an inoperative position
Data Source
AI summary
The valve has: a body projecting an inlet duct and an outlet duct; a seat in the inlet duct and cooperating with a sealing ball; a helical spring between the sealing ball and a supporting ball; a rotor mounted on the body and having a cam surface, cooperating with the supporting ball; a locking member having a magnet and housed within each cavity of the rotor, and to be moved between operative and inoperative positions; a spring in each cavity and forcing the locking member into the operative position; and retention housings, each of two of the latter being opposite to each other, receiving one of the locking members in the operative position, in a rotational position of the rotor.