Composite Cylinder Weight Reduction in Trenchless Straightening Press

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Solution Overview

Problem

Straightening press devices for trenchless pipeline construction are heavy, making them difficult to transport and increasing the risk of accidents due to their weight, despite being designed for high pressures and temperatures.

Innovation Solution

A straightening press unit with double-acting cylinders coated in fiber-reinforced composite material, featuring a high-pressure hose or steel pipe with a bend and pluggable connections, and a compact design that reduces weight while maintaining operational pressures and temperatures, including a press rod holder and yoke for efficient force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If solid steel elements are used to ensure the straightening press can withstand high pressures and temperatures, then the device can operate at high pressures (150 bar or more) and temperatures (80 to 100°C or higher), but the weight of the straightening press increases significantly (easily reaching 85 kg)

Engineering Contradiction:
Improvepressure resistanceVSAvoiddevice weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining a metal inner tube (providing strength and pressure resistance) with an outer shell made of fiber-reinforced plastic or rubber material (providing protection and structural support). This composite construction allows the cylinder to withstand high pressures and temperatures while significantly reducing the overall weight compared to solid steel construction, directly resolving the technical contradiction between strength and weight.

Inventive Principle:
Principle #40Composite materials

2Strength

If the straightening press is constructed with solid steel elements to handle high pressures, then the device can maintain structural integrity under load, but the transport difficulty increases significantly (posing a major challenge for transport up stairs into a basement)

Engineering Contradiction:
Improvestructural integrityVSAvoidtransport ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The composite construction of metal inner tube with fiber-reinforced plastic or rubber outer shell provides sufficient structural integrity for high-pressure operation while reducing weight to make transport feasible, directly addressing the contradiction between structural integrity and transport ease.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The device is divided into separable components: the claw carrier with claws can be removed from the straightening press for transport and subsequently reattached in the basement. This segmentation allows the main body to be transported more easily while the heavy claw carrier is handled separately, resolving the transport difficulty.

Inventive Principle:
Principle #1Segmentation

3Weight of moving object

If the cylinder is made lighter using fiber-reinforced composite material, then the overall device weight is reduced, but the ability to withstand high pressures and temperatures may be compromised

Engineering Contradiction:
Improvecylinder weightVSAvoidpressure and temperature resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent uses a composite material system where the metal inner tube provides the necessary pressure and temperature resistance, while the fiber-reinforced plastic or rubber outer shell provides structural support and protection. This composite approach enables weight reduction while maintaining or even enhancing the ability to withstand high pressures and temperatures through the synergistic combination of materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different parts of the cylinder have different material properties optimized for their specific functions: the inner tube is made of metal for direct contact with hydraulic fluid and resistance to pressure and temperature, while the outer shell is made of lighter fiber-reinforced plastic or rubber for structural support and protection. This local differentiation of material quality allows weight reduction without compromising overall strength.

Inventive Principle:
Principle #3Local quality

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 significantly reduces the weight of the straightening press unit by 20% or more, facilitating safer and easier transport, maintaining operational performance, and preventing accidents by ensuring the device can handle vertical forces without deformation.

Implementation Method 1

the inner tube of the cylinder (2) is covered with a fiber-reinforced composite material (26)

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

the hydraulic oil line (6), which is connected to the longitudinal or Transverse bore (24) of the cylinder end (25), forms a first hydraulic oil line (61), said first hydraulic oil line being in the form of a high-pressure hose or a high-pressure steel pipe

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP4261385B1Straightening press unit for a trenchless line construction
Publication Date: 2024.11.13 DWL BAUMASCHINEN AG
  • EP4261385B1 patent drawingFigure 1
  • EP4261385B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to a straightening press unit (1) for a straightening press for trenchless pipeline construction, comprising at least one double-acting cylinder (2) with inner tube and piston rod (22) with piston, wherein the cylinder (2) has a longitudinal or transverse bore (24) in the region of each cylinder end (25), a fixing block (3) for receiving and fixing the cylinder (2), a press rod holder (4), a yoke (5) which connects the piston rod (22) of the cylinder (2) to the press rod holder (4), at least one first (61) and second (62) hydraulic oil line (6), wherein the at least one cylinder (2) is arranged between the fixing block (3) and the yoke (5), characterized in that i) the inner tube of the cylinder (2) is sheathed with a fiber-reinforced composite material (26), and ii) the first hydraulic oil line (6) is in the form of a high-pressure hose or a high-pressure steel pipe.wherein the high-pressure steel pipe has a bend of at least 30°, in particular at least 45°, and/or is provided with at least one pluggable connection.