Endoscope Switching Valve Anti-Rotation Mechanism
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Solution Overview
Problem
Existing switching valve assemblies for endoscopes face challenges in rotational regulation of the piston unit within the cylinder, which affects the performance of fluid suction and compression, particularly due to issues with anti-rotation projections and groove complexity, leading to reduced suction efficiency and increased complexity.
Innovation Solution
A compact switching valve assembly with a piston unit that includes a valve head, end rod, and button device, utilizing a biasing mechanism with compression coil springs and regulating means to prevent rotation, ensuring alignment of flow channels and maintaining performance without excessive complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-rotation projections and grooves are added to prevent piston rotation, then rotational regulation is improved, but device complexity increases
Solution Approach 1:
The piston unit incorporates an asymmetric anti-rotation projection that engages with a corresponding asymmetric groove in the cylinder. This asymmetric geometry prevents rotational movement while maintaining a relatively simple structure, avoiding the need for complex multi-component locking mechanisms.
Solution Approach 2:
The anti-rotation projection is integrated directly into the piston unit structure, combining the rotational constraint function with the existing piston geometry. This merging approach eliminates separate rotational restraint components, reducing overall device complexity while ensuring reliable rotational regulation.
2Reliability
If the piston unit structure is made more complex to ensure rotational regulation, then reliability is improved, but suction efficiency decreases
Solution Approach 1:
The anti-rotation projection is strategically positioned at a specific location on the piston unit where it engages with the groove to prevent rotation without interfering with the suction flow path. This localized approach ensures rotational regulation while maintaining open and efficient suction channels, avoiding the need for complex structures in the flow path area.
3Reliability
If the groove is made more complex to engage with the anti-rotation projection, then rotational regulation is improved, but manufacturing difficulty increases
Solution Approach 1:
The rotational regulation function is segmented into two simple geometric features: the anti-rotation projection on the piston unit and the corresponding groove in the cylinder. This segmentation allows each feature to be manufactured independently using standard machining operations, avoiding the need for complex integrated structures and reducing manufacturing difficulty.
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 allows for rotational regulation of the piston unit within the cylinder, enhancing fluid suction and compression performance while maintaining a compact structure, thus addressing the limitations of previous designs.
Implementation Method 1
a biasing means of a two-stage type is secured to the cylinder on an upper side of the cylinder passage, for biasing the piston unit in the upward direction from the down position
Data Source
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AI summary
A switching valve assembly for an endoscope (10) has a cylinder (50) and a piston unit (51) , which includes a valve head (51b) , a flow channel (71, 72), an end rod (51a) and a button device (43, 47). The piston unit is settable in an initial position, a down position and a halfway position to change over flow lines (28, 46). A biasing unit (52) of a two-stage type is secured to the cylinder on an upper side of the cylinder passage, biases the piston unit, and stops the piston unit in the halfway position when the button device is pushed in a downward direction from the initial position. A first regulating device (67, 102) prevents the piston unit from rotating relative to the biasing unit. A second regulating device (64, 94) prevents the biasing unit from rotating relative to the cylinder, so as to ensure alignment of a channel opening of the flow channel with one of the flow openings upon sliding the piston unit.