Grooved Screw Nail Structure for Removable Drywall Fixing
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Solution Overview
Problem
Existing screw nails used in dry construction for connecting plane components to metallic substructures often fail to be removed without damaging the materials, as the thread slips in thin holding plates, leading to inefficient unscrewing and increased costs due to incorrect insertions and material displacement.
Innovation Solution
The screw nail design features axially aligned grooves on its shaft to allow penetration without rotational movement, creating material projections for grip and thread cutting during unscrewing, along with a fine thread and self-cutting thread flanks for secure removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional screw nail with a standard thread is used to connect plane components to a metallic substructure, then the connection is initially secure, but the screw nail cannot be removed without damaging the materials because the thread slips in thin holding plates
Solution Approach 1:
The thread is divided into two distinct segments: a fine thread for initial penetration and material displacement, and a steep thread for final anchoring. This segmentation allows the screw nail to perform different functions at different stages of insertion, enabling both secure connection and subsequent removability.
Solution Approach 2:
The screw nail design incorporates a dynamic insertion process where the functional characteristics change during insertion. The fine thread operates first to displace material, then the steep thread engages to provide anchoring. This dynamic behavior allows the same fastener to achieve both secure connection and controlled removal.
2Reliability
If the screw nail rotates during insertion to cut a thread in the material, then anchoring is improved, but the thin sheet metal is chipped away or material is totally displaced, preventing subsequent thread formation and removal
Solution Approach 1:
The insertion process is segmented into two phases: first the fine thread displaces material without rotation, preserving material integrity; then the steep thread provides anchoring. This segmentation prevents the chipping and total displacement that would occur with conventional rotating insertion.
Solution Approach 2:
Instead of rotating the screw nail during insertion to cut a thread (conventional approach), the invention inverts the approach by using a fine thread that penetrates without rotation, displacing material in the direction of insertion. The anchoring is then achieved through the steep thread geometry rather than through rotational thread cutting.
3Ease of manufacture
If a fine thread is provided on the screw nail shaft to prevent material structure destruction, then material integrity is maintained, but the screw nail cannot be sufficiently unscrewed because only the metallic substructure has sufficient strength to form a thread
Solution Approach 1:
The thread structure is segmented into a fine thread for material-friendly penetration and a steep thread for extraction. The fine thread maintains material integrity by preventing structural destruction, while the steep thread provides the necessary anchoring geometry for subsequent unscrewing, solving the contradiction between material preservation and extraction capability.
Solution Approach 2:
The thread geometry parameters are changed along the shaft length. The fine thread has small pitch and depth for gentle material engagement, while the steep thread has larger pitch and depth for strong anchoring. This parameter change enables the screw nail to achieve both material integrity preservation and sufficient extraction capability.
Data Source
AI summary
The present invention relates to attachment mean (1) for connecting plane components in dry construction, in particular for fixing two-dimensional construction material to a metallic substructure, having a shaft (2) on one end region of which a point (3) and on the other end region of which a head (4) are formed, a fine thread (5) being formed on the shaft (2) in order to increase extraction values of the attachment means (1), at least in regions, a number of grooves (6) being provided on the shaft (2) which extend substantially parallel to the central axis (X) of the shaft (2).