Hydraulic Torque Tool Pneumatic Piston Return

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Solution Overview

Problem

Hydraulically powered bolting tools require significant space and complexity due to mechanical springs for energy storage and multiple hydraulic connections for piston retraction, limiting energy density, tool size, and accessibility.

Innovation Solution

An internal pneumatic energy storage assembly that compresses during the advance stroke and expands during the retract stroke of the piston, eliminating the need for hydraulic lines and reducing the number of hydraulic connections, allowing for a more compact design and simplified hydraulic pump controls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a mechanical spring is used to store energy for cylinder retraction, then the tool can operate portably, but the tool volume increases significantly due to limited energy density

Engineering Contradiction:
Improveenergy densityVSAvoidtool volume
Core Design Contradiction:
Use of energy by moving objectVSVolume of stationary object

Solution Approach 1:

The patent replaces the mechanical spring with a pneumatic energy storage system using compressible gas (such as nitrogen) contained in a reservoir. The gas compresses during the advance stroke and expands during the retract stroke, providing the necessary energy for cylinder retraction. This pneumatic approach achieves higher energy density compared to mechanical springs, allowing for a more compact tool design while maintaining portable operation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Device complexity

If separate hydraulic lines are used to advance and retract the cylinder, then the hydraulic system is simple to understand, but the number of connections increases, increasing tool size and complexity

Engineering Contradiction:
Improvehydraulic system complexityVSAvoidnumber of hydraulic connections
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent combines the advance and retract functions into a single hydraulic connection system. The internal pneumatic energy storage device provides the retraction force, eliminating the need for a separate retract hydraulic line. This merging reduces the number of hydraulic connections from two (advance and retract lines) to one, thereby reducing tool size, simplifying the hydraulic pump, and decreasing overall system complexity while maintaining ease of understanding.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If multiple hydraulic connections are required for cylinder operation, then the hydraulic system provides complete control, but the tool footprint increases and accessibility is reduced

Engineering Contradiction:
Improvetool accessibilityVSAvoidtool footprint
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent extracts the retract hydraulic connection from the system by replacing it with an internal pneumatic energy storage device. This elimination of the retract line reduces the number of external connections required, thereby minimizing the tool footprint and improving accessibility to the work space. The single remaining hydraulic connection for the advance function can be positioned optimally without the constraint of requiring space for a second retract connection.

Inventive Principle:
Principle #2Taking out (Extraction)

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 increases energy density, reduces tool size, enhances bolting speed, improves accessibility, and simplifies the hydraulic system, leading to a more reliable and efficient hydraulically driven torque tool.

Implementation Method 1

an internal energy storage assembly which operates by a pneumatic fluid which compresses during an advance stroke of a piston assembly of tool (1) and expands during a retract stroke of the piston assembly

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

an internal energy storage assembly which operates by a pneumatic fluid which compresses during an advance stroke of a piston assembly of tool (1) and expands during a retract stroke

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3668685B1Apparatus for tightening threaded fasteners
Publication Date: 2024.10.23 HYTORC DIV UNEX CORP
  • EP3668685B1 patent drawingFigure 1A~1B
  • EP3668685B1 patent drawingFigure 2
  • EP3668685B1 patent drawingFigure 3~4

AI summary

An apparatus for use with a hydraulically driven torque tool for tightening or loosening threaded fasteners including an internal energy storage assembly for automatic piston return is disclosed. In one embodiment, the internal energy storage assembly operates by a pneumatic fluid which compresses during an advance stroke of a piston assembly of the tool and expands during a retract stroke of the piston assembly of the tool. In such embodiment, the internal energy storage assembly includes a hydraulic assembly and a pneumatic assembly. Advantageously it: has a higher energy density than a mechanical spring; does not have geometric limitations as the pneumatic fluid may be contained in internal volume available of the tool; and increases bolting speeds as the return stroke no longer requires hydraulic fluid to force back the piston; has reduced tool size by elimination of one hydraulic connection and location of the remaining connection that improves accessibility of the tool into the work space; requires a simplified hydraulic pump and controls; and increases bolting system reliability.