Dual Piston Fastener Tool for Tight Clearance

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Solution Overview

Problem

Existing fastener installation tools face challenges when installing pull-type fasteners near the edge of a structure due to limited clearance, as they struggle to apply the necessary axial forces effectively in tight spaces.

Innovation Solution

A dual piston, close clearance fastening tool is designed with two diametrically opposed pistons and a yoke mechanism, allowing for axial force application along a longitudinal axis, and includes a housing with fluid communication between the pistons to facilitate both pull and return motions, enabling efficient installation of fasteners with reduced center-to-edge distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional single-piston fastener installation tool is used, then the tool structure is simple, but the tool cannot effectively apply axial forces in tight clearance spaces near the edge of a structure

Engineering Contradiction:
Improveclearance capabilityVSAvoidtool structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The tool is divided into two separate cylinders (first and second cylinders) positioned diametrically opposed to each other, each with its own piston. This segmentation allows the force application points to be separated spatially, enabling operation in tight clearance spaces while maintaining the necessary force application capability through the yoke mechanism that connects both pistons to the nose assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-axis force application (conventional) to a dual-diametrically-opposed cylinder arrangement. By positioning cylinders in different spatial dimensions (diametrically opposed about the longitudinal axis), the tool achieves improved clearance capability in radial directions while maintaining axial force application through the yoke linkage.

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

2Length of moving object

If the center-to-edge distance is reduced for fastener installation, then the tool can access tighter spaces, but the ability to apply necessary axial forces is compromised

Engineering Contradiction:
Improvecenter-to-edge distanceVSAvoidaxial force application
Core Design Contradiction:
Length of moving objectVSForce

Solution Approach 1:

By segmenting the force application into two separate diametrically opposed cylinders, the tool can position its force application points closer to the edge while still achieving the necessary total axial force through the combined action of both pistons transmitted via the yoke to the nose assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The yoke mechanism merges the force output from both diametrically opposed pistons into a unified axial force application at the nose assembly. This combining effect allows the tool to achieve the necessary total axial force even when each individual piston operates from a position with reduced clearance to the edge.

Inventive Principle:
Principle #5Merging (Combining)

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 tool effectively reduces the center-to-edge distance for fastener installation, allowing for precise and efficient application of both pull and return forces, thereby addressing the challenge of tight clearance requirements in fastener installation.

Implementation Method 1

the first piston includes a pull pressure port adapted to receive a fluid pressure causing the first piston to move in a pull direction

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

the second piston includes a return pressure port adapted to receive a fluid pressure causing the second piston to move in a return direction

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP3283244B1Dual piston close clearance fastening tool
Publication Date: 2020.12.02 HOWMET AEROSPACE INC
  • EP3283244B1 patent drawingFigure 1~2
  • EP3283244B1 patent drawingFigure 3~4
  • EP3283244B1 patent drawingFigure 5

AI summary

A fastener installation tool (10) includes a nose assembly (30), first (18) and second (20) cylinders, first (14) and second (16) pistons, and a yoke (22). The nose assembly (30) is adapted to apply an axial load to a fastener along a longitudinal axis of the nose assembly (30). The first (18) and second (20) cylinders are diametrically opposed to one another with respect to the longitudinal axis of the nose assembly (30). The yoke (22) connects the first piston (14), the second piston (16), and the nose assembly (30) such that motion of one of the pistons (14, 16) causes motion of the other one of the pistons (14, 16) and motion of at least a portion (32) of the nose assembly (30).