Screw Shank Segmentation for Friction Reduction in Hard Workpieces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional screws with helical threads face significant frictional resistance when driven into hard wooden or cement workpieces, leading to fractures and increased time and strength requirements for assembly.
Innovation Solution
A screw design featuring a shank with a front section of roughly triangular cross-section and raised teeth, a conical drilling tail for wooden workpieces, and a second thread for cement workpieces, reducing friction and facilitating easy insertion by cutting and enlarging holes with reduced contact areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional screw with helical thread is used, then the screw can be driven into workpieces, but considerable frictional resistance is generated causing fractures in hard wooden workpieces
Solution Approach 1:
The screw shank is divided into multiple sections with different cross-sectional shapes: a front section with triangular cross-section and raised teeth for cutting, an intermediate section with circular cross-section for threading, and a rear section for engagement. This segmentation allows each section to perform its specific function - the front section cuts through material with reduced friction, while the intermediate section provides threading engagement.
Solution Approach 2:
Different sections of the screw shank have different local properties: the front section has triangular cross-section with raised teeth for cutting action, the intermediate section has circular cross-section for thread formation, and specific sections have different diameters. This local quality variation optimizes performance for each functional zone - cutting at the front, threading in the middle, and engagement at the rear.
2Ease of operation
If a traditional screw with helical thread is used, then the screw provides coupling function, but it takes much time and consumes more strength to drive the screw into hard cement workpieces
Solution Approach 1:
The front section of the screw with triangular cross-section and raised teeth performs preliminary cutting action on the workpiece material before the threaded sections engage. This preliminary cutting creates a pathway and reduces material resistance, making the subsequent threading process faster and requiring less driving force, especially in hard cement workpieces.
3Productivity
If the screw has a front section with raised teeth for cutting, then the screw can drill and enlarge holes smoothly, but the structure becomes more complex
Solution Approach 1:
The invention merges multiple functions into a single screw component: the front section with raised teeth performs both drilling and hole enlargement, the intermediate section forms threads, and the rear section provides engagement. This merging of functions into one integrated component achieves high productivity without requiring separate drilling and fastening operations, while the complexity is managed through continuous geometric transitions between sections.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A screw (10) includes a shank (12) and at least one thread (26). The shank (12) includes a front section (14), a rear section (16) spaced from the front section (14) along a longitudinal axis (X) of the shank (12), and an intermediate section (18) between the front and rear sections (14, 16). A head (22) is formed at an upper end of the rear section (16). The intermediate section (18) has circular cross sections, and the front section (14) has roughly triangular cross sections. A plurality of separate raised teeth (30) is provided on a circumference of the front section (14), and each of the plurality of raised teeth (30) extends along the longitudinal axis (X) of the shank (12). The thread (26) is spirally formed on the shank (12) and includes a plurality of thread convolutions (28). The screw (10) can be quickly driven into workpieces to be combined without less combination between the screw (10) and the workpieces.