Pluri-Lobed Socket Head Screw for Multi-Wrench Tightening

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Solution Overview

Problem

Existing screw designs with socket heads are inefficient when tightened with wrenches other than those with complementary profiles, often causing deformations and reduced efficiency, especially when using hexagonal wrenches.

Innovation Solution

A screw with a pluri-lobed socket head that allows efficient tightening with specific, Torx, and hexagonal wrenches by featuring convex protrusions with inclined side faces and a center flush face, enabling increased axial load and reduced deformation, while maintaining versatility and efficiency according to ISO standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional polygonal or hexagonal wrench is used to tighten the screw, then the operation is simpler and more versatile, but deformation of the socket occurs and tightening efficiency is reduced

Engineering Contradiction:
Improvewrench compatibilityVSAvoidsocket deformation
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The socket profile features localized geometric variations with protrusions having specific convex shapes and inclined faces at predetermined locations, allowing different regions of the socket to interact differently with various wrench types. This local differentiation enables the socket to accommodate multiple wrench profiles while maintaining optimal contact zones that prevent deformation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of designing the wrench to fit a standard socket, the invention inverts the approach by designing a non-standard socket profile that actively accommodates multiple wrench types. The socket's protrusions with inclined faces are designed to guide and support various wrench geometries, reversing the traditional adapter-from-wrench-to-socket paradigm.

Inventive Principle:
Principle #13The other way round (Inversion)

2Manufacturing precision

If a special pluri-lobed wrench with complementary profile is used, then tightening efficiency is maximized and deformation is minimized, but the operation becomes more complex and less versatile

Engineering Contradiction:
Improvesocket deformationVSAvoidwrench profile complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The socket is designed with a multi-functional profile that serves multiple purposes: it provides precise engagement for specialized pluri-lobed wrenches to maximize tightening efficiency, while simultaneously accommodating standard hexagonal and Torx wrenches. The protrusions with inclined faces create contact zones that adapt to different wrench geometries, making the socket universally compatible without requiring a specialized wrench for basic operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If protrusions with inclined side faces meeting at a center edge are used, then wrench insertion is facilitated, but the front length geometry becomes more complex

Engineering Contradiction:
Improvewrench insertionVSAvoidprotrusion geometry
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The inclined side faces of the protrusions are pre-configured to guide the wrench into the correct position during insertion. The faces are angled to naturally direct the wrench toward the center edge contact point, providing self-alignment and facilitating easy insertion without requiring precise manual positioning. This preliminary geometric guidance simplifies the operation while the overall protrusion structure remains relatively simple.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3523545B1Screw with socket head
Publication Date: 2022.05.04 FONTANA FASTENERS RD SRL
  • EP3523545B1 patent drawingFigure 1~2

AI summary

The screw (10) has a longitudinal axis (12) and comprises a threaded shank (13) and a head (14) wherein a socket (16) is formed to be engaged by a wrench and having a pluri-lobed outer profile comprising a series of lobes (18) circumferentially offset and separated by a series of circumferentially offset protrusions (20) of the head (14). Each protrusion is delimited by two flanks (22) and a front length (24) joining the radially inner ends of the flanks (22) and is convex and symmetrical with respect to a center axis (26) radially oriented with respect to the longitudinal axis (12). The front length (24) is formed by a center face (28) and two inclined side faces (30) each of which joins the radially inner end of the respective flank (22) with a respective end of the center face (28), which is oriented orthogonally with respect to the center axis (26) of the protrusion (20).