Pneumatic-Hydraulic Valve Venting to Reduce Pull-Down Resistance
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Solution Overview
Problem
Existing pneumatic-hydraulic control valves require significant force to operate due to negative pressure generation, leading to potential cable breakage, especially when the valve needs to be positioned at the top end of a lifting seat post, where an axial air channel is not feasible, making operation inconvenient and prone to failure.
Innovation Solution
A pneumatic-hydraulic control device with a piston pin having an axial air channel and an acting assembly that includes a sleeve tube and acting member forming an exhaust channel, allowing residual air to discharge externally and prevent negative pressure buildup, reducing the force required to open the valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piston pin is pulled down by a cable to open the valve, then the valve can be operated, but negative pressure is generated between the piston pin and the end wall of the piston seat, requiring excessive force that can easily cause the cable to break
Solution Approach 1:
The patent introduces air channels (first air channel in the piston pin, second air channel in the lifting seat post) that allow air to escape from the sealed space before the piston pin is fully pulled down. This preliminary air release prevents negative pressure buildup, reducing the force needed to operate the valve and preventing cable breakage
2Adaptability or versatility
If the pneumatic-hydraulic control valve is set at the top end of the lifting seat post to match different styles, then adaptability is improved, but an acting rod must be used instead of a cable, and the acting rod cannot provide an axial air channel, so negative pressure still builds up and operation remains difficult
Solution Approach 1:
The patent divides the air escape path into multiple segments: the first air channel in the piston pin, the second air channel in the lifting seat post, and the air hole at the bottom end of the piston pin. This segmented approach allows air to escape through multiple pathways, ensuring that even when the valve is positioned at the top end with an acting rod, negative pressure is effectively prevented and operation remains easy
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 effectively reduces the pull-down resistance and prevents cable breakage by allowing air to escape, making the operation of the pneumatic-hydraulic control device more convenient and reliable, even when positioned at the top end of a lifting seat post.
Implementation Method 1
the residual air between the piston seat and the piston pin flows through the axial air channel and the air hole to reach the exhaust channel
Implementation Method 2
a negative pressure is generated between the first force-receiving portion of the piston pin and the end wall of the piston seat
Data Source
AI summary
A pneumatic-hydraulic control device includes a piston seat mounted in a cylinder, a piston pin disposed in the piston seat and having an axial air channel, and an acting assembly. When the piston pin is closed, hydraulic oil cannot flow between the piston seat and the piston pin, so that the cylinder cannot be moved. When the piston pin is opened, hydraulic oil flows between the piston seat and the piston pin, so that the cylinder can be moved. The acting assembly includes a sleeve tube connected with the piston seat and an acting member connected with the piston pin and inserted in the sleeve tube to form an exhaust channel. The exhaust channel communicates with the axial air channel to eliminate negative pressure generated between the piston pin and the piston seat when the piston pin is pulled down, thereby reducing a pull-down resistance of the piston pin.