Aircraft Shear Jaw Geometry for Riveted Aluminum Cutting
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Solution Overview
Problem
Conventional shearing machines struggle to effectively dismantle large aircrafts made of high-strength aluminum alloys due to issues with pinching and cutting, particularly in areas with riveted structures like the body and wings, where the cutting edge often fails to initiate the cutting process and faces excessive wear.
Innovation Solution
A shearing machine design featuring a tip blade with a narrow point that pierces the aluminum alloy first, followed by parallel shearing blades that widen the cut, and a hydraulic system to concentrate pressure on the point of contact, allowing for controlled shearing even in riveted areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional shearing machine with standard cutting edges is used to cut high-strength aluminum alloy aircraft structures, then the cutting machine can handle ordinary scrap materials, but the cutting edge fails to initiate cutting on riveted aluminum alloy surfaces and experiences excessive wear
Solution Approach 1:
The patent applies local quality by providing different surface treatments to different parts of the cutting edge. The tip portion has a different surface roughness or coating compared to the body portion, allowing the tip to effectively penetrate riveted surfaces while the body maintains durability and reduces wear during the rubbing cutting phase.
Solution Approach 2:
The patent changes the surface parameters of the cutting edge through specific surface treatments (such as coating, polishing, or roughening) to optimize performance. The tip portion receives a treatment that enhances penetration capability, while the body portion receives a treatment that reduces friction and wear during the shearing process.
2Reliability
If the cutting edge is designed to forcefully penetrate riveted surfaces, then cutting initiation improves, but the burden on the cutting edge increases and the workpiece cannot be pinched and cut
Solution Approach 1:
The cutting edge is designed with local quality differentiation where the tip portion has enhanced penetration properties through surface treatment, while the body portion has reduced friction properties. This allows the tip to initiate cutting with minimal force by penetrating the riveted surface, while the body portion facilitates smooth material flow and rubbing cutting without excessive burden.
Solution Approach 2:
The cutting edge is segmented into functionally distinct zones: a tip portion for penetration and a body portion for shearing. Each segment has optimized surface characteristics - the tip is treated for penetration while the body is treated for reduced friction - allowing the overall system to cut riveted structures without excessive force requirements.
3Device complexity
If a standard jaw design is used for shearing aluminum alloy, then the machine structure remains simple, but the cutting edge cannot maintain favorable contact and rubbing state throughout the cutting process
Solution Approach 1:
The jaw design incorporates local quality by applying different surface treatments to different regions of the jaw facing. The region corresponding to the cutting edge contact zone has surface treatment optimized for maintaining favorable rubbing and sliding conditions, while other regions maintain standard finishes. This ensures continuous favorable contact during the shearing process without requiring complex overall jaw redesign.
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
Enables efficient dismantling of large aircrafts by ensuring the cutting edge initiates and maintains contact, reducing wear and facilitating clean cuts through high-strength aluminum alloys, even in riveted sections.
Implementation Method 1
a first hydraulic driving means that rotates the first jaw portion around the fulcrum; and a second hydraulic driving means that rotates the second jaw portion around the fulcrum
Implementation Method 2
a tip blade whose point bites first into an object to be sheared
Data Source
Figure 1~2
Figure 3a~4
Figure 5a~5d
AI summary
A shearing machine for dismantling large aircrafts suitable for dismantling aircrafts, such as airliners, using a high-strength aluminum alloy or the like can be obtained. As shearing blades of a first jaw portion, the shearing machines includes: a tip blade whose point bites into an object to be sheared; a pair of first parallel shearing blades that are bent at an obtuse angle to the biting direction of the tip blade and disposed both sides of the blade width; and a pair of second parallel shearing blades that are bent at an obtuse angle to an attaching portion of the first parallel shearing blades and disposed on both sides of the blade width. The shearing machine further includes shearing blades of a second jaw portion provided with receiving blades for these shearing blades. As the tip blade, the shearing machine includes: a point blade having an end portion and a pair of tip tapered blades which are disposed on both sides of the end portion and whose blade width is increased toward the rear end; and a pair of tapered blades that are bent at an obtuse angle to an attaching portion of the rear end portion of the tip tapered blades and disposed toward the first parallel shearing blades.