Clamping Screw Torque Distribution in Switching Devices

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Solution Overview

Problem

Existing installation switching devices face challenges in distributing the tightening torque of clamping screws without loading the housing parts excessively, leading to potential distortion or breakage, and require higher material costs for a stable connection plate.

Innovation Solution

A connection plate with a holding section that locks a separate, independently designed threaded element, allowing the torque to be absorbed by the plate rather than the housing, using a threaded element like a nut, and distributing the force to prevent local peaks, enabling a high-quality, thin metal connection plate with reduced material costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the threaded element is integrated into the connection plate, then the connection plate provides sufficient stability to absorb tightening torque, but the material costs increase and production becomes more complex

Engineering Contradiction:
Improvestability of connection plateVSAvoidproduction complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The threaded element is separated from the connection plate into an independent component. The connection plate contains only a through hole for the screw shaft, while the threaded element (nut) is a separate part that receives the clamping screw. This segmentation allows the connection plate to be made of thin, high-quality metal with high electrical conductivity without requiring integrated threading, thus reducing material costs and simplifying production while maintaining stability through the separate threaded element.

Inventive Principle:
Principle #1Segmentation

2Strength

If the threaded element is integrated into the housing, then the housing provides structural support, but the tightening torque causes excessive housing loads leading to distortion or breakage

Engineering Contradiction:
Improvestructural supportVSAvoidhousing distortion
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The threaded element is extracted from the housing structure and positioned on the connection plate instead. The holding section on the connection plate locks the threaded element, creating a dedicated load-bearing path for the tightening torque. This extraction prevents the housing from bearing the full tightening load, eliminating the risk of housing distortion or breakage while maintaining structural support through the connection plate assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the connection plate is made of thin high-quality metal, then material costs are reduced and electrical conductivity is improved, but the plate cannot absorb high tightening torque without warping

Engineering Contradiction:
Improvematerial costVSAvoidtorque absorption
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The connection plate is designed without integrated threading, allowing it to be made of thin, high-quality metal with high electrical conductivity. The threading function is segmented into a separate threaded element that handles the mechanical torque loads. This division allows the connection plate to be optimized for electrical conductivity and cost-effectiveness while the separate threaded element provides the necessary torque absorption capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2424045B1Installation device with a connection clamp assembly
Publication Date: 2016.05.18 ABB AG(DE)
  • EP2424045B1 patent drawingFigure 1
  • EP2424045B1 patent drawingFigure 2
  • EP2424045B1 patent drawingFigure 3

AI summary

The invention relates to an installation switching device (1) with an insulating housing (2) and a terminal arrangement (11) for connecting a conductor (12) with an annular terminal shoe (14) to a terminal plate (16) mounted inside the device, with a clamping screw (15) having a screw head (17) and a screw shank (18), wherein the screw shank (18) penetrates the annular terminal shoe (14) when the conductor (12) is clamped and engages with a threaded element (50), comprising a terminal receiving chamber (10) with an insertion opening (27) for the conductor (12) and an access opening (28) to the screw head (17) for actuating it. The terminal plate (16) has a retaining section (51) for locking the threaded element (50).