Hydraulic Hand Pump Locking and Unloading Valve Design
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Solution Overview
Problem
Conventional two-stage hand pumps require additional effort during the second stage to return fluid to the reservoir, limit mechanical advantage due to restricted handle pivot distance, and often have protruding tie rod nuts that increase length without enhancing reservoir capacity, and lack integral and user-friendly handle locking mechanisms.
Innovation Solution
A two-stage hand pump with an unloading valve assembly and handle locking mechanism, featuring a rotatable and retractable lock plunger and counter-bored nut, which reduces effort during the second stage, enhances mechanical advantage through pivoting links, and integrates the tie rod nut to maximize reservoir volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a direct-acting relief valve is used to return fluid during the second stage, then fluid can be returned to the reservoir, but additional operator effort is required and oil volume and pressure delivery are decreased
Solution Approach 1:
The relief valve is designed to automatically open and close based on pressure differential without requiring operator intervention. The valve body with inlet and outlet ports, combined with the spring mechanism, creates a self-regulating system that returns fluid during the second stage without adding to the operator's pumping effort.
2Length of moving object
If the distance between the pivot point and piston is limited, then the pump structure is compact, but the mechanical advantage of the handle is reduced and more pumping effort is required
Solution Approach 1:
The handle pivot point is positioned at an optimized distance from the piston, creating an effective lever arm that maximizes mechanical advantage. This dimensional optimization of the pivot location allows for greater pumping efficiency without increasing the overall pump length, resolving the contradiction between compact size and operational ease.
3Strength
If a tie rod nut protrudes from the housing, then the tie rod can be secured, but the overall length of the pump is increased without increasing reservoir capacity
Solution Approach 1:
The tie rod nut is positioned within the housing structure rather than protruding from it. The tie rod passes through the housing and is secured by the nut on the interior side, allowing the tie rod to be firmly anchored while maintaining a compact overall pump length and maximizing reservoir capacity within the available space.
4Ease of operation
If a locking device is added to the handle, then the handle can be locked down, but the device complexity increases and the lock may be prone to damage or misplacement if not integral
Solution Approach 1:
The locking mechanism is integrated directly into the handle assembly as an integral component rather than being a separate attachment. The lock plunger and spring mechanism are built into the handle structure, providing secure locking capability while minimizing additional complexity and eliminating the risk of the lock being damaged or misplaced as a separate part.
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 efficient fluid transfer with reduced operator effort, increased mechanical advantage, and a compact design with an integral handle lock, enhancing the pump's efficiency and usability.
Implementation Method 1
a locking end can interact with a head portion of the lock screw to prevent the handle from moving away from the housing
Implementation Method 2
In the second stage, only the high pressure portion contributes to moving the hydraulic fluid to the piston/cylinder assembly while the low pressure portion returns the hydraulic fluid back to the reservoir
Implementation Method 3
A two-stage hand pump with an unloading valve assembly and handle locking mechanism, featuring a rotatable and retractable lock plunger and counter-bored nut, which reduces effort during the second stage, enhances mechanical advantage through pivoting links
Data Source
AI summary
A method and apparatus is provided that includes a hand pump having a handle locking mechanism, a counter bored nut, pivoting links, and unloading valve assembly. The unloading valve assembly allows a pump operator to pump a larger volume of hydraulic fluid and/or to pump to higher pressures in first stage operation than a conventional pump which employs a direct-acting relief valve. The unloading valve also decreases the effort required to pump the handle during second stage operation. The handle locking mechanism allows the pump handle from moving during transporting and storing of the hand pump. The counter bored nut allows for more reservoir room than conventional hand pumps. The pivoting link allows for greater leverage of the handle during pumping.