Threaded Filling Member for Counterbore Hole Detachment
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Solution Overview
Problem
Existing methods for filling counterbore holes with a bolt head to prevent foreign matter entry are either difficult to repair or replace, as the filling member either remains attached too tightly or detaches during use, complicating maintenance and repair processes.
Innovation Solution
A method involving a filling member with female threads, made of synthetic resin, that is slightly larger than the counterbore hole, allowing for easy detachment by applying an extracting force through the threads or a pushing force, and a counterbore hole design with slopes to facilitate removal of foreign matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling member is filled in a tight state to prevent foreign matter entry, then foreign matter prevention is improved, but ease of repair and replacement deteriorates
Solution Approach 1:
The filling member is segmented into two functional zones: an enlarged head portion that remains embedded in the counterbore hole to prevent foreign matter entry, and a protruding shaft portion that extends outward to enable easy engagement with removal tools. This segmentation allows the filling member to simultaneously provide sealing function and facilitate maintenance operations.
Solution Approach 2:
The protruding shaft portion acts as an intermediary element between the embedded filling member and external removal tools. It provides a mechanical interface that allows technicians to apply leverage and rotational force to remove the filling member without directly manipulating the embedded portion, thereby simplifying the repair process while maintaining the tight seal during operation.
2Ease of operation
If the filling member is filled in a loose state to enable easy detachment, then ease of operation is improved, but foreign matter prevention deteriorates
Solution Approach 1:
The filling member exhibits local quality differentiation: the head portion has a larger diameter than the counterbore hole opening, creating an interference fit that prevents foreign matter entry, while the shaft portion has a reduced diameter that protrudes outward to enable tool engagement. This local quality variation allows the same component to provide both tight sealing and easy removability.
Solution Approach 2:
The filling member design enables dynamic transition between two states: during normal operation, the enlarged head portion remains embedded in the counterbore hole providing a tight seal; during maintenance, the protruding shaft portion allows external tools to apply force and rotate the filling member out of the hole. The design accommodates both stationary sealing and dynamic removal requirements.
3Reliability
If the filling member dimension is larger than the counterbore hole opening, then foreign matter prevention is improved, but insertion difficulty increases
Solution Approach 1:
The counterbore hole incorporates a tapered portion with a specific inclination angle that curves inward from the opening toward the bottom. This curved geometry allows the enlarged head portion of the filling member to be gradually guided into the hole during insertion, reducing the impact of the size difference and facilitating easier installation while maintaining the interference fit for foreign matter prevention.
Solution Approach 2:
The counterbore hole geometry is modified by introducing a tapered section with a controlled inclination angle. This parameter change in the hole shape creates a transition zone that accommodates the larger diameter of the filling member head, enabling smooth insertion despite the size mismatch between the filling member and the final sealed position.
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3(a)~3(d)
AI summary
To present a detaching method of a filling member and a filling member to be used therein in which the filling member loaded in a space of a counterbore hole or a hole of a bolt head may be detached easily if required to remove the bolt, for the ease of repair or replacement, a prepared hole is made in a filling member 3 by means of a drill D, and female threads 31 are formed in the filling member by tapping process, and an extracting force is applied to the filling member by way of the female threads 31 engaged with the rotating tap T, so that the filling member 3 can be pulled out of the space of the counterbore hole 2.