Clevis Articulation Spindle Blocking Device for One-Sided Assembly
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Solution Overview
Problem
Existing fastener assemblies for connecting aircraft engines to wings require free space on both sides for assembly, making it difficult to assemble from a single side, especially with smaller articulation spindles, and are challenging to install due to the need for high torque and specialized tools.
Innovation Solution
An assembly design featuring a cylindrical stop and a bolt-and-nut system that can transition between locked and unlocked states, allowing the articulation spindle to be immobilized in translation from a single side, with a double anti-rotation system for secure locking without requiring extensive tooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional blocking device with nut and pin is used to immobilize the articulation spindle, then the spindle is securely locked, but free space is required on both sides of the clevis for assembly
Solution Approach 1:
The blocking device is segmented into a modular assembly comprising a blocking member with threaded bore, a locking member with engagement protrusion, and a retaining member. This segmentation allows the components to be assembled sequentially from one side of the clevis, eliminating the need for free space on both sides while maintaining secure locking through the distributed functional elements.
Solution Approach 2:
The locking member is nested within the blocking member, with the engagement protrusion fitting into the threaded bore. The retaining member then secures the locking member in place. This nested arrangement allows all components to be contained within the space available on one side of the clevis, resolving the contradiction between secure locking and assembly accessibility.
2Reliability
If high torque is applied to secure the blocking device, then reliable locking is achieved, but specialized tools and complex installation are required
Solution Approach 1:
The engagement protrusion on the locking member acts as an intermediary mechanical feature that translates rotational motion into axial locking force. When the locking member is rotated, the engagement protrusion engages with the threaded bore, converting torque into secure locking without requiring excessive force or specialized tools. The retaining member then maintains this locked state.
Solution Approach 2:
The blocking device is designed to be self-locking through the interaction between the engagement protrusion and the threaded bore. Once the locking member is rotated into position, the threading automatically maintains the locked state without requiring continuous application of torque or specialized tools. The retaining member simply needs to be installed to prevent reverse rotation, simplifying the installation process.
Data Source
AI summary
An assembly having an articulation spindle mounted in a first sleeve inserted into a first arm of a clevis and in a second sleeve inserted into a second arm of said clevis. The assembly comprises a blocking device which comprises a cylindrical stop housed in an extension of the second sleeve and comprising a front face against which a second end of the articulation spindle can come to bear, and a bolt-and-nut able to adopt a locked state, in which it passes through the stop and the extension so as to immobilize the stop in the extension, and an unlocked state, in which it does not pass through the stop and allows the stop to be removed from the extension.