Self-Locking Mount Pin with Conical Shoulder Load Distribution
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Solution Overview
Problem
Existing load distributing pin designs for gas turbine engines face issues with installation binding and stress due to misalignment between manufacturing tolerances, leading to undesirable shear loading and structural stress, particularly in 'hook and latch' type designs.
Innovation Solution
A self-locking mount pin with a conical chamfer region that forms a conical shoulder, allowing normal compressive loading and reducing reliance on bolt preload, combined with a spherical bearing and bushing for improved alignment and load distribution, and a method to form apertures and chamfers concurrently to minimize residual assembly stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a captured self-locking thread is used in the pin design, then anti-rotation and self-locking requirements are satisfied, but installation binding and stress occur due to misalignment between manufacturing tolerances
Solution Approach 1:
The patent introduces a spherical bearing at the shoulder region of the pin, replacing the traditional cylindrical geometry with a spherical interface. This curved geometry provides self-aligning capability that accommodates manufacturing tolerances and prevents installation binding while maintaining anti-rotation functionality through the captured self-locking thread.
Solution Approach 2:
The spherical bearing acts as an intermediary element between the pin shoulder and the mounting component aperture. This mediator absorbs the misalignment caused by manufacturing tolerances, allowing the captured self-locking thread to function properly without experiencing installation binding or excessive stress.
2Ease of manufacture
If clearances are increased on the hole or bushing to mitigate misalignment issues, then installation binding is reduced, but a larger percentage of load is transferred through bolt threads in shear which is structurally undesirable
Solution Approach 1:
The spherical bearing provides a curved load-bearing surface that distributes forces more evenly across the joint. This geometry allows for smaller clearances while still accommodating misalignment, thereby maintaining structural integrity and reducing shear loads on the threads compared to traditional flat-interface designs.
Solution Approach 2:
The spherical bearing pre-aligns the pin and mounting component during installation, establishing proper force distribution pathways before the self-locking thread engages. This preliminary alignment ensures that loads are transferred through the optimized shoulder interface rather than being forced through the threads, maintaining structural strength.
3Weight of moving object
If a lighter weight pin design is implemented, then weight reduction is achieved, but structural strength and load distribution may be compromised
Solution Approach 1:
The pin design incorporates a spherical bearing which may be made from different materials optimized for specific functions - the bearing surface for low friction and wear resistance, and the pin body for strength-to-weight ratio. This composite approach allows weight reduction in non-critical areas while maintaining load-bearing capacity where needed.
Solution Approach 2:
The spherical geometry of the bearing concentrates and distributes loads more efficiently through its curved surface compared to flat interfaces. This allows for reduced material usage in the pin body while maintaining adequate load distribution capability, achieving weight reduction without compromising structural strength.
Data Source
Figure 1
Figure 2~3
AI summary
A mounting pin assembly (60) includes a first mounting component (106). The assembly also includes a second mounting component (102) having a first leg (104) located on a first side of the first mounting component and a second leg (108) located on a second side of the first mounting component. The assembly further includes a mount pin (100) extending through an aperture of the first leg, an aperture of the first mounting component, and an aperture of the second leg, the mount pin having a conical shoulder region (114) in contact with a chamfer (120) of the second leg. The assembly yet further includes a self-locking nut plate (109) threaded to the mount pin.