Anti-seizing Bolt Incomplete Screw Vertical Groove
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Solution Overview
Problem
Conventional seizure prevention bolts fail to prevent seizure caused by oblique insertion and foreign matter invasion, such as welding spatter, in environments like automobile assembly lines, where accurate axis alignment and thread protection are critical.
Innovation Solution
A seizure prevention bolt with an incomplete screw portion having a larger outer diameter than the female screw's inner diameter and a vertical groove for cutting out foreign matter, preventing forced engagement and spatter-induced seizure by allowing correct alignment and spatter discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a guide with smaller diameter than the normal screw portion is formed at the front end of the bolt, then position correction effect is improved, but seizure due to oblique insertion can occur at the screw portion having the smaller diameter
Solution Approach 1:
The screw portion is segmented into two distinct zones: a guide portion with smaller diameter for position correction, and an incomplete screw portion with larger diameter than the female screw's inner diameter that prevents seizure. This segmentation allows each zone to perform its specific function without compromising the other.
Solution Approach 2:
Different portions of the bolt have different diameters tailored to their specific functions. The guide portion has a smaller diameter optimized for alignment, while the incomplete screw portion has a larger diameter optimized for preventing seizure during oblique insertion.
2Reliability
If conventional seizure prevention bolts are used, then seizure due to oblique insertion is prevented, but seizure caused by invasion of foreign matter such as spatter cannot be prevented
Solution Approach 1:
The harmful foreign matter (spatter) is extracted or removed from the engagement interface by designing the incomplete screw portion with a larger diameter than the female screw's inner diameter, creating a clearance that prevents spatter from being crushed between mating threads.
Solution Approach 2:
The incomplete screw portion acts as an intermediary zone between the guide portion and the normal screw portion, providing a transition area with increased diameter that prevents direct engagement and spatter crushing while maintaining thread engagement functionality.
3Productivity
If the bolt is forcedly screwed into the female screw by use of a power driver in a state where the axis of the bolt is slightly inclined, then threading is achieved, but seizure occurs possibly leading to inability to remove the bolt easily
Solution Approach 1:
The guide portion with smaller diameter performs preliminary alignment action before the incomplete screw portion engages with the female screw. This preliminary positioning prevents oblique insertion from causing seizure during forced screwing operations.
Data Source
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AI summary
There is provided a seizure prevention bolt capable of preventing seizure caused by oblique insertion as well as seizure caused by invasion of a foreign matter such as a spatter. An incomplete screw portion 12 having an outer diameter d that is larger than an inner diameter D1 of a female screw 20 and smaller than (D + D1)/2 is formed at a front end of a normal screw portion 11 formed in a bolt shaft over one or more pitches, and a vertical groove 14 for cutting out a foreign matter such as a spatter is formed in the incomplete screw portion 12. D in the above expression is a nominal diameter of the bolt.