Positioning Cone Nut for Flush Borehole Alignment and Torque

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing screw nuts cannot be pre-positioned on a workpiece without external positioning and holding forces, and applying torque to create a screw connection often results in the nut being pushed out of position or not allowing torque application.

Innovation Solution

A screw nut design featuring a positioning cone with a tapered opening and a stop washer extending transversely to the screw axis, allowing alignment and wedging into a borehole without blocking the alignment, enabling torque application and preventing loosening, with optional features like longitudinal grooves and locking pins for additional support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the nut is simply placed flush with a drilled hole without external positioning forces, then the installation process is simplified, but the fastener pushes the nut out of position due to lacking external fixing force

Engineering Contradiction:
Improveinstallation simplicityVSAvoidnut positioning accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The positioning cone enables the nut to self-position and self-wedge into the workpiece bore without requiring external positioning fixtures or holding forces. The conical geometry automatically guides the nut into correct alignment and secures it through wedging action when the fastener is inserted.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The positioning cone utilizes a conical (curved) surface instead of a flat or prismatic end section. This curved geometry provides the necessary guidance and wedging characteristics to maintain nut position during fastener insertion while allowing simple flush placement against the workpiece surface.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If the nut is driven into the workpiece with a positioning cone to enable pre-positioning, then the nut can be aligned over the borehole, but applying torque to create the screw connection becomes blocked

Engineering Contradiction:
Improvenut alignment accuracyVSAvoidtorque application capability
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The nut is segmented into two functional parts: a positioning cone for alignment and wedging, and a prismatic base body for torque application. This segmentation allows each part to perform its specific function without interfering with the other - the cone provides positioning while the flat base body surfaces enable tool engagement for torque application.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the nut have different geometric properties tailored to their specific functions. The positioning cone has a tapered geometry optimized for alignment and wedging, while the base body has flat surfaces optimized for tool engagement. This local differentiation of geometric quality resolves the contradiction between positioning and torque application.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the wall thickness at the free end of the positioning cone is made thin to facilitate driving into the workpiece, then insertion becomes easier, but the structural stability of the cone is reduced

Engineering Contradiction:
Improveinsertion easeVSAvoidpositioning cone stability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The positioning cone performs its guiding and alignment function before the main fastening action occurs. The thin-walled design is sufficient for the preliminary insertion and positioning phase, after which the fastener provides the primary structural support. The cone's stability requirement is reduced because its main function is completed early in the assembly process.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables secure alignment and torque application without external positioning, reduces loosening, and provides stable screw connections even with varying workpiece materials, accommodating longer fasteners and distributing forces evenly.

Implementation Method 1

Due to the conical shape of the positioning cone, the nut wedges itself in the workpiece without blocking the alignment between the borehole and the threaded hole

Methodology Applied
Scientific EffectWedge: Wedge

Implementation Method 2

the opening of the positioning cone, which tapers towards the base body and leads into the threaded hole, serves several functions: First, it directs the applied force on the nut away from the screw axis when a fastener is inserted into a borehole

Methodology Applied
Scientific EffectForce direction through geometric taper: Geometry

Implementation Method 3

the positioning cone has a striking edge at its free end section for driving into a workpiece

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP4375520B1Nut having a base body and a threaded bore
Publication Date: 2025.11.12 STELZHAMMER BERND
  • EP4375520B1 patent drawingFigure 1
  • EP4375520B1 patent drawingFigure 2
  • EP4375520B1 patent drawingFigure 3

AI summary

A screw nut is described, comprising a base body (1) and a positioning cone (2) connected to the base body (1), the positioning cone having a threaded bore (3) and an opening (8) that tapers towards the base body (1) and opens into the threaded bore (3). To design a screw nut of the aforementioned type so that it can be positioned flush over a borehole in a workpiece without external positioning and holding forces, and yet still allow the necessary torque to be applied to the screw nut for creating the screw connection, it is proposed that the positioning cone (2) for driving into a workpiece (5) has a striking edge (7) at its free end section (6) that limits the opening (8).