Inline TBM Cutter Mounting Wedge Clamping

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Solution Overview

Problem

Conventional tunnel boring machine (TBM) cutter assembly mounting systems are insecure, difficult to access, and prone to rapid failure due to high dynamic forces and debris issues, making maintenance and replacement challenging, especially in deep tunnels with high ambient pressures.

Innovation Solution

An inline mounting system for TBM cutter assemblies using a pair of housing mounts with wedge and back support assemblies that securely clamp the cutter assembly shaft without requiring lateral shift, allowing direct inline insertion and removal, enhancing stability and simplifying maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional L-shaped channel mounting is used, then cutter assembly can be installed, but the mounting is insecure and prone to rapid failure under high dynamic forces

Engineering Contradiction:
Improvemounting securityVSAvoidmounting system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mounting system is divided into separate functional components: mounting plates with inline channels, wedge assemblies for clamping, and support blocks for positioning. This segmentation allows each component to perform its specific function optimally while improving overall reliability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using L-shaped channels that require lateral shifting, the patent uses inline longitudinal channels that receive the shaft directly in line with the mounting plate. This inverted approach eliminates the need for lateral movement and provides more secure inline mounting under high dynamic forces.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If wedge-lock assemblies with lateral shift are used, then cutter assembly can be secured, but installation and maintenance are difficult due to limited access

Engineering Contradiction:
Improveinstallation easeVSAvoidmounting security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The mounting system inverts the conventional approach by using longitudinal inline channels instead of L-shaped channels. This allows the shaft to be inserted directly in line with the mounting plate, eliminating the need for lateral shifting and making installation and maintenance much easier while maintaining secure mounting.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The inline channel acts as an intermediary element that guides the shaft into proper position during installation and allows for easy removal. This mediator component simplifies the entire installation and maintenance process while ensuring reliable mounting during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If shallow wedge angle is used, then mechanical advantage is improved, but the cutter assembly is more sensitive to debris and misalignment

Engineering Contradiction:
Improveclamping forceVSAvoidmounting stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent merges the wedge assembly with support blocks that provide both clamping force and alignment guidance. This combination allows the use of a shallow wedge angle for mechanical advantage while the support blocks prevent sensitivity to debris and misalignment by providing stable reference surfaces.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support blocks serve as intermediary elements between the wedge assembly and the cutter assembly shaft. These blocks provide stable alignment references that reduce sensitivity to debris and misalignment, allowing the shallow wedge angle to function effectively for generating clamping force.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If heavy cutter assemblies are used, then cutting performance is improved, but replacement and maintenance become extremely difficult

Engineering Contradiction:
Improvecutting capabilityVSAvoidmaintenance ease
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The mounting system inverts the conventional approach by using inline longitudinal channels that allow heavy cutter assemblies to be installed and removed by simple linear motion rather than complex lateral shifting. This makes maintenance of heavy cutters feasible while maintaining their cutting performance.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The inline channel and support blocks act as intermediaries that facilitate the installation and removal of heavy cutter assemblies. These components provide guidance and support that make handling and replacing heavy cutters much easier while allowing the cutters to maintain their full cutting capability during operation.

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 inline mounting system provides secure and reliable attachment of cutter assemblies, reducing the risk of failure and simplifying maintenance by ensuring proper seating and alignment, while allowing for easier installation and removal without lateral movement, thus improving operational reliability and reducing maintenance needs.

Implementation Method 1

a wedge assembly comprising a first elongate attachment member that extends through an aperture in the first guide and a wedge that engages a distal end of the first elongate attachment member

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Implementation Method 2

The wedge is configured to slideably engage the first inwardly extending shaft supporting portion, and to slideably engage the shaft such that the shaft is clamped between the wedge and the second inwardly extending shaft supporting portion

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 3

a back support assembly comprising a clamp block that abuts the back abutment surface, a bridge block that abuts the front abutment surface, and a second elongate attachment member that extends through an aperture in the clamp block and an aperture in the bridge block

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3368745B1Cutter assembly with inline mounting
Publication Date: 2020.02.12 THE ROBBINS CO
  • EP3368745B1 patent drawingFigure 1
  • EP3368745B1 patent drawingFigure 2
  • EP3368745B1 patent drawingFigure 3

AI summary

An inline mounting assembly (100) for a TBM cutter assembly (115) includes first and second housing mounts (120), having upper and lower ear portions (121), and an inline channel (123) sized to receive an end of the cutter assembly. The housing mounts include a first guide (122) and a second guide (124) defining forward and rearward abutment faces. A wedge assembly (130) includes a bolt that extends through the first guide and engages a wedge (132) configured to clamp the cutter shaft (117) to the housing mount. A back support assembly includes a clamp block (142) that abuts the rearward abutment face, a bridge block (143) that abuts the forward abutment face, and a bolt that extends through the blocks. The bridge block abuts the shaft to provide support.