Hydraulic Tool Regenerative Extension for Two-Speed Piston Control

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Solution Overview

Problem

Hydraulic tools lack the ability to adjust piston speed and force application dynamically based on the task requirements, such as transitioning from rapid advancement to precise cutting or crimping, which limits their efficiency and precision.

Innovation Solution

Incorporating a hydraulic actuator cylinder with a piston that divides into two chambers, a regeneration check valve, and a pilot-operated valve, allowing the piston to move at different speeds and apply varying forces by switching between regeneration and powered extension modes based on pressure thresholds, enabling efficient crimping or cutting operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If fluid flows through the regenerative extension fluid path, then the piston moves at high speed, but the force application is limited

Engineering Contradiction:
Improvepiston speedVSAvoidforce application
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The system dynamically switches between two operational modes using a pilot-operated valve: regenerative extension mode for high-speed movement and powered extension mode for high-force application. This dynamic switching allows the hydraulic tool to adapt its characteristics based on task requirements, resolving the contradiction between speed and force

Inventive Principle:
Principle #15Dynamics

2Force

If fluid flows through the powered extension fluid path, then the force application increases, but the piston speed decreases

Engineering Contradiction:
Improveforce applicationVSAvoidpiston speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The pilot-operated valve enables dynamic switching between powered extension mode (high force, low speed) and regenerative extension mode (low force, high speed). This allows the system to optimize performance for different operational phases, resolving the speed-force tradeoff

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a single-speed hydraulic system is used, then the device complexity is reduced, but the adaptability to different task requirements decreases

Engineering Contradiction:
Improvetask adaptabilityVSAvoidhydraulic system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hydraulic system is segmented into two distinct fluid paths (regenerative extension path and powered extension path) with a pilot-operated valve controlling switching between them. This segmentation allows independent optimization of each path for specific functions while maintaining overall system adaptability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pilot-operated valve acts as an intermediary component that controls switching between different hydraulic paths based on pilot pressure. This mediator enables the system to adapt to different task requirements without requiring complex multi-functional components

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the piston to move at variable speeds and apply different forces, enhancing the tool's efficiency and precision by rapidly advancing before crimping or cutting and applying increased force when needed, thereby improving the overall performance of hydraulic tools.

Implementation Method 1

a pump configured to draw fluid from the fluid reservoir and provide fluid to the first chamber via a hydraulic supply line

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a piston within the hydraulic actuator cylinder, the piston including a piston head, the piston head dividing an internal space of the hydraulic actuator cylinder into a first chamber and a second chamber

Methodology Applied
Scientific EffectHydraulic force transmission: Hydraulic Press

Implementation Method 3

a regeneration check valve disposed in a regenerative extension fluid path that fluidly couples the second chamber to the first chamber

Methodology Applied
Scientific EffectCheck valve flow control: Valve

Implementation Method 4

The pilot-operated valve includes a first port that is fluidly coupled to the second chamber, a second port that is fluidly coupled to the fluid reservoir, and a pilot port that is fluidly coupled to the hydraulic supply line via a pilot line

Methodology Applied
Scientific EffectPressure-actuated valve operation: Valve

Data Source

PatentEP4025389B1Tool with hydraulic system for regenerative extension and two-speed operation
Publication Date: 2023.08.30 MILWAUKEE ELECTRIC TOOL CORP
  • EP4025389B1 patent drawingFigure 1
  • EP4025389B1 patent drawingFigure 2
  • EP4025389B1 patent drawingFigure 3

AI summary

Embodiments of the invention provide a hydraulic tool including a hydraulic actuator cylinder, a piston, a fluid reservoir, a pump, a regeneration check valve, and a pilot-operated valve. The regeneration check valve is disposed in a regenerative extension fluid path that fluidly couples a first and second chamber of the hydraulic actuator cylinder. The pilot-operated valve is disposed in a power extension fluid path that fluidly couples the second chamber to a fluid reservoir.