Caged Nut Connection for One-Sided Plate Assembly

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Solution Overview

Problem

Existing connection systems for plate-like components often require access from both sides, making it difficult to assemble components with limited space, especially when tools cannot be easily applied to the mother component.

Innovation Solution

A connecting system comprising a screw and a mother with a screw canal and a cage to hold the mother, allowing for easy attachment from one side without the need for counter-fixation with a screwdriver. The mother has a foot section and a head section with a larger cross-sectional area at the foot section, enabling lateral force absorption and secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional screw and nut connection is used, then the connection is secure and can absorb lateral forces, but access from both sides is required making assembly difficult in confined spaces

Engineering Contradiction:
Improveassembly accessibilityVSAvoidconnection system structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The nut is segmented into two distinct parts: a head section with a screw channel for receiving the screw, and a base section with a larger cross-sectional area that protrudes beyond the head section. This segmentation allows the nut to function as both a fastening element and a lateral force absorber, eliminating the need for access from both sides while maintaining connection security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a conventional two-sided access requirement to one-sided access by adding dimensional complexity to the nut structure. The base section extending perpendicular to the screw axis creates a hammerhead configuration that absorbs lateral forces in a different dimensional plane, allowing secure connection from a single access side.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the nut is held in a cage during screwing, then handling from one side is easy without counter-fixation, but the device complexity increases

Engineering Contradiction:
Improvenut handlingVSAvoidconnection system components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A cage is introduced as an intermediary component that holds the nut during the screwing process. The cage provides a receiving space for the nut and allows the screw to be inserted through it, enabling one-handed operation without requiring a second tool to hold the nut. The cage acts as a temporary holding structure that facilitates easy assembly from one side.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the base section has a larger cross-sectional area than the head section, then lateral forces are absorbed effectively, but the manufacturing complexity increases

Engineering Contradiction:
Improvelateral force absorptionVSAvoidnut geometry
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The nut is designed with an asymmetric hammerhead configuration where the base section has a larger cross-sectional area than the head section. This asymmetric design is optimized for lateral force absorption while the stepped transition between sections provides clear manufacturing guidelines. The asymmetric shape is achieved through standard forming processes that create the two distinct sections with different cross-sectional areas.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3971427B1Connection system for connecting at least two, in particular plate-like elements, arrangement with such a connection system
Publication Date: 2025.05.14 J SCHMALZ GMBH
  • EP3971427B1 patent drawingFigure 1
  • EP3971427B1 patent drawingFigure 2
  • EP3971427B1 patent drawingFigure 3

AI summary

The invention relates to a connection system (10) for connecting at least two elements, in particular plate-like elements. The connection system (10) comprises a screw (12), a nut (14) corresponding to the screw (12) with a screw channel (17) extending along a screw axis (15) into which the screw (12) can be screwed, and a cage (16) for receiving the nut (14). The nut (14) has a base section (22) and a head section (20) extending along the screw axis (15), the base section (22) projecting at least partially beyond the head section (20) in a direction perpendicular to the screw axis (15). The invention also relates to an arrangement (11) comprising such a connection system (10).