Recessed Head Screw Driving Socket Geometry for Secure Tool Engagement

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Solution Overview

Problem

Conventional screws experience loose engagement with driving tools, leading to inefficient force transfer and increased risk of the screw falling off, especially due to loose fitting and slanted socket designs, which complicates operations and reduces working efficiency.

Innovation Solution

A recessed head screw design featuring a precision-processed driving socket located between the driving recess and the top face, allowing for close-fitting engagement with variously shaped driving tools, ensuring secure retention and even force delivery, thereby preventing tool escape and screw drop-off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the driving socket dimension is made slightly less than the driving tool dimension for easy insertion, then the ease of operation is improved, but the engagement firmness deteriorates

Engineering Contradiction:
Improveease of insertionVSAvoidengagement firmness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The driving socket is divided into two functional zones: an upper engagement portion with a smaller diameter that provides firm engagement with the driving tool, and a lower insertion portion with a larger diameter that facilitates easy insertion. This segmentation allows the socket to simultaneously achieve both easy insertion and firm engagement without compromise.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the driving socket has slanting walls to accommodate various socket types, then the adaptability is improved, but the force transfer efficiency deteriorates

Engineering Contradiction:
Improvesocket type compatibilityVSAvoidforce transfer efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The driving socket employs different wall geometries in different regions: the upper engagement portion has substantially vertical walls to ensure efficient force transfer and prevent tool slippage, while the lower insertion portion maintains slanting walls for adaptability. This local differentiation allows the socket to maintain both versatility and force transfer efficiency.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If magnetic force is used to attract the screw head for engagement, then the ease of operation is improved, but the magnetic force deteriorates over time due to iron debris

Engineering Contradiction:
Improveengagement easeVSAvoidmagnetic force stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention extracts and eliminates the magnetic attraction mechanism from the driving socket design. Instead of relying on magnetic force to hold the screw head, the design uses a purely mechanical engagement system where the upper engagement portion of the socket provides firm physical retention. This eliminates the problem of magnetic force degradation from iron debris while maintaining ease of operation through the optimized geometry.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3150867B1Recessed head screw
Publication Date: 2019.03.27 HUMBOLDT STATE UNIVERSITY
  • EP3150867B1 patent drawingFigure 1
  • EP3150867B1 patent drawingFigure 2
  • EP3150867B1 patent drawingFigure 3

AI summary

A recessed head screw (3) includes a shank (31), a head (32), a drilling portion (33) and threads (34). The head (32) includes a top face (321) where a socket portion (323) is formed. The socket portion (323) has a driving recess (3231) and a driving socket (3232) formed between the driving recess (3231) and the top face (321). The driving socket (3232) communicates with the driving recess (3231). A diameter value (r1) of the driving socket (3232) is a maximum circumscribed circle diameter value (r2) of the driving recess (3231) plus a value within 20% of the maximum circumscribed circle diameter value (r2). When a driving tool (5) engages the socket portion (323), the driving socket (3232) can be in close-fitting engagement with the driving tool (5) to increase the engagement between the driving tool (5) and the head (32).