Variable Ratio Hand Pump Lever Pivot Dynamics
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Solution Overview
Problem
Hydraulic hand pumps with fixed lever pivot points experience increased force requirements at higher pressures, leading to lateral loading on compensation cylinders and premature failure.
Innovation Solution
A hand-operated hydraulic pump design where the lever pivot is connected to a cam that pivots away from the housing, reducing the distance between the lever pivot and pump plunger as output pressure increases, thereby reducing the force needed to operate the pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the lever pivot point is fixed, then the pump structure is simple, but the force required to operate the pump increases at higher pressures
Solution Approach 1:
The patent applies the dynamics principle by making the lever pivot point movable instead of fixed. The pivot point is connected to the pump plunger through a linkage mechanism that allows it to move dynamically. As the pump plunger moves during operation, the lever pivot point automatically adjusts its position, changing the moment arm length to optimize the mechanical advantage and reduce the force required to operate the pump at different stroke positions.
2Force
If the lever pivot distance to plunger is reduced, then the operating force is reduced, but lateral loading on the compensation cylinder increases causing premature failure
Solution Approach 1:
The patent uses the dynamics principle to create a moving pivot point that adjusts its position during the pump cycle. This dynamic adjustment allows the system to maintain an optimal balance between reducing operating force and minimizing lateral loading on the compensation cylinder. The pivot point moves in coordination with the plunger displacement, ensuring that the moment arm is optimized for force reduction while the geometry of the linkage prevents excessive lateral forces on the compensation cylinder.
Solution Approach 2:
The patent introduces an intermediary linkage mechanism between the lever pivot point and the pump plunger. This intermediary structure mediates the interaction between the lever and plunger, allowing the pivot point to follow a controlled path that reduces operating force while preventing harmful lateral loading on the compensation cylinder. The intermediary linkage acts as a kinematic constraint that guides the pivot point motion to achieve both objectives.
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
This design minimizes side loads on the compensation cylinder, reduces user effort at higher pressures, and maximizes flow rate by dynamically adjusting the lever pivot distance based on output pressure, extending the pump's operational lifespan.
Implementation Method 1
reducing the distance between the lever pivot point and pump plunger reduces the amount of force required to be applied to produce a given pressure
Implementation Method 2
the lever pivot is connected to a cam that pivots away from the housing, reducing the distance between the lever pivot and pump plunger as output pressure increases
Data Source
AI summary
A hand operated hydraulic pump has a cam that is pivoted by a compensation cylinder that rotates the cam so as to move the pivot of an operating handle closer to the pump plunger as the output pressure of the pump increases.