Countersinking Screw With Inclined Protrusions and Knife Sheets

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Solution Overview

Problem

Existing screws face issues with dregs accumulation in drilling holes, leading to hole expansion and cracking, as well as the risk of the screw head embedding causing further damage due to its larger diameter compared to the hole.

Innovation Solution

A screw design featuring a head with inclined protrusions and knife sheets that extend to an enlarged stem portion, allowing for effective dregs removal and hole expansion, ensuring the screw head can be embedded smoothly without cracking, with the knife sheets cutting and expanding the hole to accommodate the screw head's larger diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the screw head has a larger outer diameter than the drilling hole, then the screw head can be securely embedded into the hole, but the hole may crack during embedding

Engineering Contradiction:

Improveembedding securityVSAvoidhole cracking

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The knife sheets perform preliminary cutting and expansion of the drilling hole before the screw head is embedded. This preliminary action creates a smoothly expanded hole that accommodates the larger screw head diameter, preventing cracking during the embedding process while ensuring secure fixation

Inventive Principle:

Principle #10Preliminary action

2Productivity

If dregs are left in the drilling hole, then drilling operation is complete, but the dregs will expand the hole and cause cracking

Engineering Contradiction:

Improvedrilling speedVSAvoidhole expansion and cracking

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The knife sheets extract and remove dregs from the drilling hole during the drilling operation. By continuously removing dregs as they are generated, the hole maintains its intended size and shape, preventing unwanted expansion and cracking while preserving efficient drilling productivity

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If the screw head is embedded into the hole without preliminary cutting and expansion, then the drilling operation is simpler, but the hole edge will be rough and cracking may occur

Engineering Contradiction:

Improvedrilling operation simplicityVSAvoidhole edge smoothness

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The knife sheets merge the functions of cutting, expanding, and smoothing the hole into a single integrated operation. This combination allows the screw head to be securely embedded with a smooth edge finish without requiring separate preliminary operations, thus maintaining operational simplicity while achieving high manufacturing precision

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10626909B2Countersinking screw capable of easily drilling holes and dregs removing

Publication Date: 2020.04.21 HUANG SHU CHIN

AI summary

A screw capable of drilling holes easily and discharging dregs effectively includes a head; and a stem. The head is formed by an upper portion and a lower portion. The upper portion is a round disk. The annular ring of the round disk of the head is formed with a plurality of inclined protrusions. Recesses between the protrusions extend from an inner edge of the round ring to an outer edge of the round ring and are arranged along un-radial paths. A periphery of the lower portion of the head is formed with at least one knife sheet which extends from the annular ring of the round disk of the head to the stem; and the direction of the knife sheet is inclined to an axis of the lower portion of the head. At a connection of the head and stem, the knife sheet has a maximum height and width.