Screw Nail Head Structure for Stable Striking and Torque Engagement
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Solution Overview
Problem
Screw nails used for fastening steel plates face issues with deformation during striking, leading to poor torque transmission and tilting, due to the deformation of annular protrusions and misalignment with rotary tools.
Innovation Solution
A screw nail design featuring a nail shaft with a sharp tip end and an enlarged head portion, equipped with convex and concave portions that allow for orthogonal striking force transmission, preventing deformation and maintaining engagement with rotary tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an annular protrusion is provided on the outer periphery of the head portion to prevent deformation, then the deformation resistance is improved, but the head diameter increases and the appearance deteriorates
Solution Approach 1:
The protrusion is extracted from the outer periphery of the head portion and relocated to the end surface. This removes the harmful effect of increased head diameter while preserving the deformation prevention function. The convex portion is positioned on the end surface opposite to the nail shaft protrusion side, away from the outer periphery that determines head diameter.
Solution Approach 2:
The protrusion is moved from a radial position (affecting head diameter) to an axial position (on the end surface). This dimensional relocation allows the protrusion to maintain its deformation resistance function without increasing the head diameter, as it now extends in the axial direction rather than radially.
2Force
If the convex portion is crushed upon striking, then the striking force transmission is improved, but the engagement between rotary tool and screw nail is hindered
Solution Approach 1:
The convex portion is extracted from the engaging portion area and placed on the end surface. This separation ensures that deformation of the convex portion during striking does not interfere with the rotary tool engagement, as the engaging portion remains distinct and undamaged.
Solution Approach 2:
The head portion is segmented into distinct functional zones: the convex portion on the end surface for striking force reception, and the engaging portion with square or hexagonal recess for rotary tool engagement. This segmentation allows independent optimization of each function without mutual interference.
3Force
If the virtual plane specified by vertexes of the convex portion is orthogonal to the axis direction, then the striking force transmission in axis direction is improved, but the design complexity increases
Solution Approach 1:
The convex portion is designed with asymmetric positioning on the end surface, arranged so that the virtual plane through its vertexes is orthogonal to the axis. This asymmetric arrangement optimizes force transmission while maintaining manufacturing simplicity through standard forming processes.
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
A screw nail (1A) includes a nail shaft portion (2) extending along one direction, and a head portion (3) whose diameter is enlarged along other direction orthogonal to an extension direction. A sharp tip end portion (20) is formed on one end side of the nail shaft portion, and the head portion is formed at an end portion on the other end side. The nail shaft portion is formed with a screw thread (21), and the head portion is formed with an engaging portion (31) capable of engaging with a rotary tool. A convex portion (32) protruding along an axis direction of the nail shaft portion is formed on an end surface of the head portion. A concave portion (33, 34) that is concave with respect to the convex portion is formed between the convex portion and the engaging portion. A virtual plane specified by vertexes of the convex portion is a plane orthogonal to the axis direction.