Adjustable Nested Washer for Aircraft Tolerance Gaps
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Solution Overview
Problem
Existing aircraft assembly methods face challenges due to dimensional tolerances between components, leading to gaps at fastening points, which are difficult to eliminate and require time-consuming selection and installation of washers to compensate for tolerance stacks.
Innovation Solution
A washer device comprising two annular components with surface regions of different levels, allowing relative rotation to adjust effective thickness, and featuring radial projections and notches for secure orientation and stability, with optional magnetic material and visual indicators for ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If washers of different thicknesses or multiple washers are used to compensate for tolerance stacks, then the gap between components can be eliminated, but the selection and installation process becomes time-consuming
Solution Approach 1:
The washer device employs a dynamic adjustment mechanism where the second annular component can rotate relative to the first annular component. This rotation changes the effective thickness of the washer device by bringing different surface regions of different levels into contact, allowing the device to adapt to various gap sizes without requiring multiple discrete washers
Solution Approach 2:
The invention changes the parameter of effective thickness dynamically through rotational adjustment. By rotating the second annular component, the contact point between the two components moves along the helical ramps, altering the effective thickness to match the required gap compensation
2Stability of the object's composition
If locking pins are added to retain the washer components in desired position, then the washer can maintain its effective thickness, but the assembly complexity and time increase
Solution Approach 1:
The invention introduces asymmetric features in the form of protrusions on one annular component and corresponding recesses on the other. These asymmetric elements engage with each other to provide automatic retention at specific rotational positions, eliminating the need for symmetric locking pins while maintaining position stability
Solution Approach 2:
The protrusion-recess features enable the washer device to self-retain at the desired effective thickness position. Once the operator rotates the components to achieve the correct gap compensation, the asymmetric features automatically engage to lock the position without requiring additional locking mechanisms
3Adaptability or versatility
If steps of different heights are used in annular components, then adjustable effective thickness is achieved, but the components are complex to manufacture to accuracy
Solution Approach 1:
The invention replaces sharp steps with continuous helical ramps on the inner surface of the annular components. This curved geometry is easier to manufacture with standard machining operations while providing the same functional effect of varying thickness. The helical ramps allow for smooth transitions and are more tolerant of manufacturing variations compared to discrete steps
4Volume of moving object
If the washer device is formed with small bearing surfaces, then the structure can be compact, but the mechanical strength is insufficient for aircraft applications
Solution Approach 1:
The invention places one annular component inside the other, creating a nested configuration. This nesting approach maximizes the bearing surface area within a compact overall volume. The first annular component with its recess provides a large bearing surface that accommodates the second component, ensuring sufficient load-bearing capacity for aircraft applications
Data Source
Figure 1~2
Figure 3a~3d
Figure 4a~5b
AI summary
A washer device 1 comprises two annular components 2, 3, each having a main face 6, 7 arranged to contact the main face 7, 6 of the other component. Each main face has surface regions of different levels along an axis of the component, such as a step 8, 9, and/or a helical ramp 9, 10. One component sits in a recess 6a in the other so that the components are nested together. Relative rotation of one component 2, 3 with respect to the other about their common axis alters the effective thickness of the washer device 1. The washer device 1 further comprises at least one radial projection 12 on one of the annular components arranged to engage with a corresponding notch 13 on the other annular component such that the annular components may be oriented in predetermined angular positions corresponding to different predetermined effective thicknesses of the washer device 1.