Ball Peen Bolt Shaft Retention Mechanism
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Solution Overview
Problem
Existing fastener systems for telecommunication cables lack a mechanism to securely prevent the nut from detaching from the shaft, especially when the cable enclosure is closed, which can lead to unintended separation during maintenance or repair operations.
Innovation Solution
A fastener system with a shaft that has a second condition where the external diameter is enlarged beyond the nut's internal diameter, ensuring the nut remains attached by deforming the shaft's threads to prevent detachment, even when the enclosure is sealed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shaft's external diameter is kept equal to the nut's internal diameter for easy assembly, then the nut can be freely attached and detached, but the nut may accidentally detach during maintenance or repair operations
Solution Approach 1:
The shaft is pre-deformed during manufacturing to create an enlarged external diameter at the second end that exceeds the nut's internal diameter. This preliminary action ensures that once the nut is assembled, it becomes permanently retained on the shaft without requiring additional locking mechanisms or assembly steps.
Solution Approach 2:
The external diameter parameter of the shaft is changed along its length, with the second end having a larger diameter than the nut's internal diameter. This parameter change creates a geometric interference fit that prevents the nut from detaching while still allowing for straightforward assembly by threading the nut onto the threaded portion of the shaft.
2Reliability
If the shaft's external diameter is enlarged beyond the nut's internal diameter to prevent detachment, then the nut remains securely attached, but the assembly process becomes more complex
Solution Approach 1:
The shaft is divided into distinct sections with different diameter characteristics: a first end with a smaller diameter for insertion, a threaded portion for nut engagement, and a second end with an enlarged diameter for retention. This segmentation allows each portion to perform its specific function while maintaining overall assembly simplicity.
Solution Approach 2:
Instead of using a nut with an enlarged internal diameter to fit over a standard shaft, the invention inverts the approach by keeping the nut's internal diameter standard and enlarging the shaft's external diameter at the retention end. This inversion simplifies nut manufacturing while achieving the same security of attachment.
3Reliability
If the shaft is deformed to enlarge its external diameter, then the nut cannot detach, but the manufacturing process requires additional deformation steps
Solution Approach 1:
The shaft material undergoes a plastic deformation phase transition during manufacturing, permanently changing its shape to create the enlarged diameter at the second end. This deformation is applied in a controlled manner during the manufacturing process, integrating the retention feature into the base manufacturing workflow without requiring separate assembly steps.
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 ensures the nut remains securely attached to the shaft, preventing accidental detachment and allowing for reliable electrical bonding and unbonding of telecommunication cables without opening the enclosure, facilitating efficient maintenance and repair.
Implementation Method 1
applying a force to the second end of the shaft to deform the second end and enlarge an external diameter of the second end
Data Source
AI summary
A fastener includes a head and a shaft extending from a first end to a second end. The first end is attached to the head. The shaft includes an external thread proximal the second end and a nut having an internal thread and an internal diameter. The second end of the shaft has a first condition and a second condition. In the first condition, an external diameter of the second end corresponds to the internal diameter of the nut such that the internal thread of the nut mates with the external thread of the shaft to attach the nut to the shaft. In the second condition, the external diameter of the second end is greater than the internal diameter of the nut such that the internal thread of the nut does not mate with the external thread of the shaft and the nut, once attached to the shaft, does not detach from the shaft.