Expandable Ball Hub Locking for Drilling Grid Attachment
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Solution Overview
Problem
Existing securing devices for drilling devices on drilling grids in the aeronautics sector face challenges in maintaining reliable attachment, particularly during hard material drilling and with worn cutting tools, leading to potential slippage and compromised geometric tolerances.
Innovation Solution
An expandable hub with locking balls is implemented, which transitions between a relaxed and expanded state to securely attach the drilling device to the grid, ensuring frictional engagement and preventing slippage through a coaxial actuator system, allowing for effective locking and unlocking control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the cylinder is increased or greater pressure is used to prevent drilling device slippage, then the reliability of attachment is improved, but the bulk and mechanical fatigue of components worsen
Solution Approach 1:
The patent changes the fundamental parameter of the attachment mechanism from pneumatic/hydraulic pressure to mechanical expansion. The expansion cone transforms rotational motion into axial movement, expanding the hub radially to create friction-based attachment. This parameter change eliminates the need for large cylinders and high pressures while maintaining reliable attachment.
Solution Approach 2:
The patent replaces the pneumatic or hydraulic cylinder system with a purely mechanical expansion mechanism. The expansion cone, driven by a simple actuator, mechanically expands the hub to achieve attachment. This substitution eliminates complex fluid power systems while improving reliability and reducing component size.
2Reliability
If additional mechanical retaining systems are implemented to prevent drilling device slippage, then the reliability of attachment is improved, but the device complexity and bulk worsen
Solution Approach 1:
The patent merges the attachment and retention functions into a single integrated expansion hub mechanism. The expanded hub simultaneously provides both the attachment force and the retention capability through friction, eliminating the need for separate retaining systems like bayonet mounts or shouldered screws.
Solution Approach 2:
The expansion hub serves multiple functions: attachment, retention, and positioning. By expanding radially, it performs all these functions simultaneously through a single mechanism, reducing overall device complexity while improving reliability compared to multiple separate systems.
3Reliability
If the axial force generated by the cylinder is increased to prevent drilling device slippage, then the reliability of attachment is improved, but the forces required for securing worsen
Solution Approach 1:
The patent uses a conical (curved) expansion surface instead of a linear cylindrical mechanism. The conical geometry of the expansion cone converts small axial movements into large radial expansion forces through mechanical advantage, reducing the axial force required while maintaining high attachment reliability through friction.
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 solution enhances the reliability of drilling operations by maintaining precise attachment, ensuring low geometric tolerances and repeatable drilling depth, while reducing the forces required for securing and minimizing mechanical stress on components.
Implementation Method 1
maintain the securing device attached to the drilling grid by friction of the expandable ring against the internal walls of one of the positioning bores of the grid
Data Source
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AI summary
The present invention relates to a device for securing (1) a drilling device (2) to a drilling grid (13) provided with a plurality of positioning bores (131), said securing device comprising means for securing to the grid (13), these means for securing comprising an expandable ball hub (123).