Curved-Head Drywall Nail to Prevent Paper Tearing and Nail Pops

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Solution Overview

Problem

Conventional nails cause tears in the outer paper of gypsum boards and lead to nail pops due to relative movement between the nail and the board, resulting in unsightly and time-consuming issues.

Innovation Solution

A nail with an inwardly tapered annular bottom surface and an inwardly curved top surface, which smoothly draws the outer paper inward without tearing and provides a cavity for joint compound, ensuring a secure attachment and reducing the likelihood of nail pops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat annular lower surface is used on the nail head, then the nail can be manufactured simply, but it tears the outer paper of the gypsum board

Engineering Contradiction:
Improvenail head manufacturing simplicityVSAvoidgypsum board paper tearing
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies curvature by replacing the flat annular lower surface with an inwardly tapered annular bottom surface that curves inward toward the shank. This tapered curved surface allows the nail head to be driven below the gypsum board surface without tearing the outer paper, as the curvature distributes the driving force more gradually across the paper surface rather than concentrating it on a flat plane.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If a flat circular upper surface is used on the nail head, then the nail structure is simple, but it causes nail pops due to relative movement between nail and gypsum board

Engineering Contradiction:
Improvenail head structure simplicityVSAvoidattachment stability preventing nail pops
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies curvature by replacing the flat circular upper surface with an inwardly curved top surface that sags inward toward the shank. This curved surface creates a cavity that allows the nail head to be driven below the gypsum board surface, preventing relative movement between the nail and board that causes nail pops. The curved geometry provides a mechanical interlock that reduces the likelihood of the nail pulling away or creating dimple nail pops.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from a two-dimensional flat surface to a three-dimensional curved surface by introducing the inwardly curved top surface and inwardly tapered bottom surface. This dimensional change creates a cavity volume beneath the original surface plane, allowing the nail head to be recessed into the gypsum board, thereby eliminating the relative movement that causes nail pops while maintaining structural integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the nail head is driven below the gypsum board surface, then a smooth finished surface can be achieved, but the flat head structure causes paper tearing

Engineering Contradiction:
Improvefinished surface smoothnessVSAvoidouter paper tearing
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies curvature through the inwardly tapered annular bottom surface that slopes gradually toward the shank. This tapered geometry allows the nail head to be driven below the gypsum board surface while the gradual slope distributes the driving force across a larger area of the outer paper, preventing tearing. The curved surface geometry enables the nail to be set below flush without concentrating stress on a single flat plane.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3586014B1Nail with a head having an inwardly curved top surface
Publication Date: 2025.03.05 ILLINOIS TOOL WORKS INC
  • EP3586014B1 patent drawingFigure 1~2
  • EP3586014B1 patent drawingFigure 3~4
  • EP3586014B1 patent drawingFigure 5

AI summary

Various embodiments of the present disclosure provide a nail with a head having an inwardly curved top surface. In one embodiment, the nail has a longitudinal axis and comprises a head, a shank, and a tip. The head includes a top portion and a bottom portion. The top portion includes an inwardly curved top surface forming a partially spherical cavity, while the bottom portion includes a radially inwardly tapered annular bottom surface. The shank is integrally connected to and extends from the bottom portion of the head. The tip is integrally connected to and extends from the shank and terminates in a free end.