Sliding Mounting Strip with Tightening Ramp for Inaccessible Duct Fastening

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Solution Overview

Problem

In aircraft engine inlet ducts, particularly in rotary wing aircraft, the location of engine components such as the engine shaft prevents access to fastening locations with traditional tools, making it difficult to achieve a proper seal between duct halves.

Innovation Solution

A method involving a sliding mounting strip with a tightening ramp is used to increase tension on fasteners, allowing for remote fastening of duct legs by sliding the strip along the mounting flange, which includes a tightening bolt and nut mechanism to secure the duct halves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional bolted flange joints are used to secure duct halves, then a proper seal can be achieved, but traditional tools such as wrenches cannot access the fastening locations due to engine component positioning

Engineering Contradiction:
Improveseal integrityVSAvoidaccessibility to fastening locations
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A mounting strip is introduced as an intermediary component that bridges the gap between the fastener and the tool. The mounting strip includes a ramp structure that allows a fastening tool to engage and apply torque to the fastener from a remote location, enabling access to otherwise inaccessible fastening positions while maintaining secure fastening

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting strip extends perpendicular to the flange surface, creating a new dimensional pathway for tool access. Instead of requiring direct lateral access to the fastener head, the tool approaches from a different spatial dimension through the ramp structure, solving the accessibility problem while maintaining fastening reliability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the mounting strip is slid to increase tension on the fastener via the tightening ramp, then secure fastening is achieved, but the mechanism requires precise geometric control of the ramp structure

Engineering Contradiction:
Improvefastener tensionVSAvoidramp geometry control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The ramp structure is designed with specific geometric parameters (angle, height, length) that transform the sliding motion into controlled fastener tension. By optimizing these parameters, the system achieves reliable fastening while allowing for standard manufacturing tolerances, balancing strength requirements with manufacturability

Inventive Principle:
Principle #35Parameter changes

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 method enables secure fastening of engine inlet ducts without traditional tools, ensuring a proper seal and preventing leakage, even in inaccessible areas, and can be applied to other components like cowlings or fairings.

Implementation Method 1

The mounting strip is slid in a direction to increase tension on the fastener via an increasing height of the tightening ramp under a fastener head of the fastener

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP2876310B1Engine inlet duct installation
Publication Date: 2018.01.10 SIKORSKY AIRCRAFT CORP
  • EP2876310B1 patent drawingFigure 1
  • EP2876310B1 patent drawingFigure 2
  • EP2876310B1 patent drawingFigure 3

AI summary

A method of securing two components (34a; 34b) to each other includes locating a mounting strip (54) at a second mounting flange (43a) of a second component (34b). The mounting strip (54) is slidably affixed to the second component (34b) and includes a plurality of strip openings (58) and a tightening ramp (60) located at each strip opening (58) of the plurality of strip openings. A first component (34a) is located such that a first mounting flange (42a) of the first component (34a) abuts the second mounting flange (42b). A plurality of fasteners (44) are located at the first mounting flange (42a). A fastener (44) of the plurality of fasteners extends through each strip opening (58) of the plurality of strip openings. The mounting strip (54) is slid in a direction to increase tension on the plurality of fasteners (44) via an increasing height of the tightening ramp (60) under a fastener head (48) of the fastener (44), thereby securing the second mounting flange (43b) to the first mounting flange (42a).