Countersunk Screw Head Structure for Burr and Fiber Cutting

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Solution Overview

Problem

Conventional screws struggle to effectively remove burrs and smooth the ragged edges of workpieces during screwing operations, leading to increased screwing resistance and potential damage to the workpiece.

Innovation Solution

The screw design incorporates cutting units along the outer edge of the head to sever fibers and smooth burrs, while ridge portions assist in cutting fibers and guiding chips into accommodation portions, which expand to accommodate the chips and reduce screwing resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the conical surface of the head is formed to be flat and smooth, then the screwing operation is simple, but the conical surface cannot scrape the burrs and smooth the ragged edge of the workpiece effectively

Engineering Contradiction:

Improveease of manufacturing the conical surfaceVSAvoidquality of edge smoothing and burr removal

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The head is segmented into multiple functional zones: a smooth conical surface for general pressing, cutting units with cutting edges for burr removal, ridge portions for fiber severing, and accommodation portions for chip collection. Each zone performs a specific function to collectively solve the edge quality problem.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the head are given different surface qualities and geometries. The conical surface remains smooth for simplicity, while localized areas (cutting units, ridge portions) are designed with cutting edges and complex geometries to perform burr removal and fiber severing functions.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the conical surface presses the drilling hole, then the screwing operation is completed, but the conical surface cannot sever fibers and the head gets entangled in unsevered fibers

Engineering Contradiction:

Improvesimplicity of screwing operationVSAvoidtight engagement between screw and workpiece

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The cutting units and ridge portions perform preliminary fiber severing and chip formation before the main pressing action of the conical surface. This preliminary action prevents fiber entanglement during the subsequent pressing operation, ensuring reliable engagement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ridge portions act as intermediaries between the cutting units and the conical surface. They sever fibers into chips and guide them into accommodation portions, preventing direct contact between the smooth conical surface and unsevered fibers that would cause entanglement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the head presses unsevered fibers, then the screwing operation continues, but the elastic recovery force increases screwing resistance and prevents tight engagement

Engineering Contradiction:

Improvecontinuity of screwing operationVSAvoidscrewing resistance

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The ridge portions extract fibers from the workpiece and transform them into chips through severing. These chips are then pushed into accommodation portions, removing the source of elastic recovery force that would otherwise increase screwing resistance and prevent tight engagement.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system discards unsevered fibers by cutting them into chips and collecting them in accommodation portions. This prevents the fibers from exerting elastic recovery force during screwing, reducing resistance and enabling tight engagement.

Inventive Principle:

Principle #34Discarding and recovering

4Productivity

If chips accumulate around the head, then the screwing operation continues, but chip accumulation increases screwing resistance and may cause workpiece cracking

Engineering Contradiction:

Improvecontinuity of screwing operationVSAvoidworkpiece cracking and increased resistance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The head incorporates accommodation portions with groove structures that provide porous-like spaces for chip accommodation. These grooves collect and contain chips during the screwing operation, preventing them from accumulating around the head and causing harmful effects.

Inventive Principle:

Principle #31Porous materials

Data Source

PatentUS12215728B2Screw

Publication Date: 2025.02.04 TAIWAN SHAN YIN INT CO LTD

AI summary

A screw includes a shank extending axially from a head and thread convolutions spirally disposed on the shank. The head has a top surface, a conical surface opposite to the top surface, cutting units extending circumferentially of the top surface, accommodation portions recessedly provided in the conical surface, and ridge portions each located between every two adjacent accommodation portions. The accommodation portions and the ridge portions extend between the cutting units and the shank. Accordingly, the cutting units sever fibers and scrape burrs which incur a ragged edge of a workpiece, thereby preventing the entanglement of unsevered fibers. The ridge portions cut fibers into chips and guide chips to the accommodation portions for suitable accommodation of chips inside the accommodation portions, which attains a tight engagement between the screw and the workpiece, reduces screwing resistance, and allows the top surface to fit level with a surface of the workpiece.