Piercing Nut Structure for Flat Mounting on Closed Sections
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Solution Overview
Problem
Conventional piercing nuts fail to maintain the original height of the mounting surface when attached to mating members with closed sectional shapes, such as square lumber and aluminum extruded material, resulting in undesirable recesses when other members are bolted.
Innovation Solution
A piercing nut design with a ring-shaped punching part height equal to or lower than the bearing surface height, a ring-shaped groove depth 1.2 to 2.0 times the plate thickness, and serrated outer peripheral walls, allowing the nut to be fixed internally without lowering the mating member's surface, using a die to punch and clinch the nut while maintaining surface contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ring-shaped punching part protrudes above the bearing surface to reliably punch the mating member, then the punching reliability is improved, but the mounting surface position is lowered forming an undesirable recess
Solution Approach 1:
The patent inverts the conventional design by making the bearing surface protrude above the ring-shaped punching part instead of the punching part protruding above the bearing surface. This inversion resolves the contradiction by allowing reliable punching through the protruding punching part while preventing mounting surface recession through the protruding bearing surface that compensates for the gap formation.
2Adaptability or versatility
If the punch is fixed inside the mating member and the die is lowered from outside to clinch the piercing nut, then the attachment to closed sectional shape is enabled, but the mating member is pushed down causing surface lowering
Solution Approach 1:
The patent inverts the conventional driving mechanism arrangement by having the punch fixed inside the mating member and the die lowered from outside, which is necessary for closed sectional shapes. Combined with the inverted height relationship between bearing surface and punching part, this resolves the contradiction by preventing the mating member from being pushed down during the clinching process.
3Reliability
If the height of the ring-shaped punching part is greater than the bearing surface height, then the punching function is improved, but the clinching property deteriorates
Solution Approach 1:
The patent changes the critical parameter of height relationship between the ring-shaped punching part and bearing surface. By setting the bearing surface height to be greater than or equal to the punching part height (H ≥ h), the patent optimizes both punching function and clinching property, resolving the contradiction between these two performance aspects.
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
Prevents surface deformation and recess formation by ensuring the mating member's surface remains flat during nut attachment, enhancing punching and clinching properties without compromising the nut's fixing strength.
Implementation Method 1
causes metal around the through hole to plastically flow into the ring-shaped groove 3 formed around the outer periphery of the ring-shaped punching part 2
Implementation Method 2
the piercing nut is clinched and fixed to the mating member W
Data Source
AI summary
A piercing nut according to the present invention includes an internal thread 11, a ring-shaped punching part 12, a ring-shaped groove 16, and a bearing surface 17. The internal thread 11 is formed at the center of a nut main body 10. The ring-shaped punching part 12 protrudes around the outer periphery of the internal thread 11. The ring-shaped groove 16 is formed around the outer periphery of the ring-shaped punching part 12. The bearing surface 17 protrudes around the outer periphery of the ring-shaped groove 16. The height h of the ring-shaped punching part 12 is equal to or lower than the height H of the bearing surface 17 in the opposite manner to the conventional technique.