Self-Drilling Screw Groove Structure for Faster Chip Removal
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Solution Overview
Problem
Conventional screws lack sufficient spaces for accommodating and moving chips generated during screwing operations, leading to increased screwing resistance, slow operation, potential workpiece cracking, and poor engagement due to chip accumulation.
Innovation Solution
The screw design incorporates a groove and slot region in the shank, providing enlarged spaces for chip discharge and accommodation, reducing resistance, and ensuring quick chip removal, thereby enhancing screwing speed and achieving a tight engagement with the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional screw design is used, then the structure is simple, but the chip discharge space is insufficient leading to increased screwing resistance
Solution Approach 1:
The screw shank surface is segmented into multiple functional zones: thread convolutions for fastening, groove for chip discharge, and slot region for chip accommodation. This segmentation allows each zone to perform its specific function efficiently, resolving the contradiction between operational smoothness and structural simplicity.
Solution Approach 2:
The invention adds a radial dimension to chip discharge by creating groove and slot regions that extend from the axial thread spaces into the radial surface of the shank. This dimensional expansion provides additional chip discharge pathways, reducing screwing resistance without overly complicating the basic screw structure.
2Productivity
If chip discharge spaces are enlarged, then screwing resistance is reduced, but the thread engagement area is decreased
Solution Approach 1:
The groove and slot regions are strategically positioned in specific local areas of the shank surface, primarily in the intermediate and lower sections. This localized modification provides chip discharge functionality where most needed while preserving thread engagement area in the critical upper sections, thus balancing screwing speed and engagement reliability.
Solution Approach 2:
The groove and slot regions are nested within the overall thread structure, with the groove situated between thread convolutions and the slot region arranged along the spiral direction. This nesting allows chip discharge spaces to be integrated within the thread geometry without significantly reducing the external thread engagement dimensions.
3Object-affected harmful factors
If chips are discharged only through narrow spaces between thread convolutions, then the screw structure remains simple, but chip discharge is slow causing workpiece cracking
Solution Approach 1:
The chip discharge function is segmented into two distinct structures: groove for primary chip discharge and slot region for secondary chip accommodation. This segmentation creates multiple egress paths for chips, preventing accumulation and workpiece cracking while maintaining reasonable structural complexity.
Solution Approach 2:
The groove acts as an intermediary channel that collects chips from the thread convolutions and directs them toward the slot region for final discharge. This intermediary structure efficiently manages chip flow, preventing direct pressure on the workpiece while adding moderate structural complexity.
Data Source
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AI summary
A screw (3) includes a shank (31) defining an exposed surface portion (311), a head (32) and a drill section (33) disposed at two opposite ends of the shank (31), and thread convolutions (34A) spirally disposed in a spiral direction and axially spaced apart. Each thread convolution (34A) has an upper thread flank (341) and a lower thread flank (342). A groove (35) is recessedly formed in the surface portion (311) and extends annularly in the spiral direction, and a plurality of slots (361) are recessedly formed in the surface portion (311) and extends axially from at least one lower thread flank (342) to meet the groove (35). Accordingly, the groove (35) and the slots (361) are adapted to enlarge spaces for moving and accommodating chips, thereby attaining a quick removal of chips, reducing screwing resistance, and accelerating a screwing operation. The accumulation of remaining chips within the groove (35) and the slots (361) facilitates a tight engagement between the screw (3) and a workpiece (4) and attains an anti-loosening effect.