Annular Flange Assembly with Positioning Peg
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Solution Overview
Problem
In low-pressure turbine assemblies, festooned annular flanges can become angularly offset during assembly, leading to insecure fastening due to bolts passing through notches instead of orifices, with no existing means to ensure proper angular positioning or alert operatives to incorrect alignment.
Innovation Solution
A device featuring a projecting element, such as a peg or stud, on one annular flange that engages with notches on the other flange to ensure correct angular positioning, preventing axial pressing when misaligned and allowing assembly operatives to correct the positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no angular positioning means are provided for festooned flanges, then the assembly process is simple and inexpensive, but the flanges may become angularly offset causing insecure fastening
Solution Approach 1:
The projecting element is pre-installed on one of the flanges before assembly. This preliminary action ensures that when the flanges are brought together, the projecting element automatically engages with the corresponding notch if the angular positioning is correct, preventing offset and ensuring secure fastening without requiring complex positioning devices during assembly
Solution Approach 2:
The projecting element and notch configuration enables the assembly system to self-check and self-correct angular positioning. If the flanges are misaligned, the projecting element cannot engage with the notch and will be blocked by the solid portion, providing automatic feedback to the operative without requiring external monitoring equipment
2Manufacturing precision
If projecting elements are added to ensure correct angular positioning, then proper alignment is ensured, but the manufacturing complexity and cost increase
Solution Approach 1:
The flange is segmented into solid portions and notches, with the projecting element integrated into one of these segments. This segmentation allows the projecting element to be designed as a simple geometric feature of the flange itself rather than a separate complex component, maintaining ease of manufacture while achieving precise angular positioning
Solution Approach 2:
The projecting element creates an asymmetric feature on an otherwise symmetric festooned flange. This asymmetric element provides a unique angular reference that ensures correct positioning, while the asymmetry is achieved through simple machining or forming operations rather than complex mechanisms
3Ease of operation
If operatives rely on manual care for angular positioning, then no additional components are needed, but positioning accuracy cannot be ensured and errors go undetected
Solution Approach 1:
The projecting element provides immediate tactile and visual feedback to the operative during assembly. When the flanges are correctly positioned, the projecting element engages smoothly with the notch; when misaligned, the projecting element is blocked by the solid portion. This feedback mechanism allows operatives to easily detect and correct positioning errors without requiring specialized measurement tools or complex procedures
Data Source
AI summary
A device for assembling together annular flanges by means of fastening bolts, in particular in a low-pressure turbine stage of the turbojet, one of the flanges has an element projecting from its face that faces the other flange and that is received in a notch in said other flange when the relative angular positioning of the two flanges is correct.