Anti-Loss Device for Machine Part Screws Using Rigid Disk and Elastic Strip

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Solution Overview

Problem

Existing anti-loss devices for machine parts are prone to screw loss during disassembly, lack reproducibility, and are not effectively secured due to the use of resilient materials that can yield over time, especially under environmental stresses, and require modifications to existing structures for installation.

Innovation Solution

An anti-loss device featuring a security unit with a rigid disk and an elastic strip, where the screw is captively held by the elastic strip, allowing for defined and reproducible attachment without disturbing the object's optics or space, and can be easily retrofitted without structural revisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If resilient material is used for captive devices, then the screw can be received resiliently, but the attachment is not reproducible and the connection can be released gradually over time

Engineering Contradiction:
Improveresilient reception of screwVSAvoidattachment reproducibility
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the physical state of the support structure from resilient to rigid, transforming the attachment mechanism from elastic deformation to precise geometric positioning. This ensures reproducible attachment conditions while maintaining ease of operation through the rigid disk's stable screw reception.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention combines rigid disk (for stable positioning) with elastic strip (for flexible connection), creating a composite structure that achieves both reproducible attachment and ease of operation. The rigid disk provides precise screw reception while the elastic strip connects it to the protective cover.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If resilient material is used for captive devices, then the screw can be received resiliently, but the elastic material can yield and lead to overload of the elastic material and/or the thread

Engineering Contradiction:
Improveresilient reception of screwVSAvoidresistance to overload
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent changes the mechanical properties of the support structure from resilient to rigid, eliminating the risk of material yielding and thread overload. The rigid disk provides stable support that prevents excessive deformation under load while maintaining the elastic strip's flexibility for connection purposes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If precise drill holes are used for positioning captive devices, then the threaded holes can be accurately positioned, but no room is left for finding the threaded holes during assembly

Engineering Contradiction:
Improvethreaded hole positioningVSAvoidassembly flexibility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention separates the positioning function (rigid disk with precise geometry) from the connection function (elastic strip). The rigid disk provides accurate positioning through its geometric features, while the elastic strip allows flexibility during assembly by accommodating minor misalignments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rigid disk acts as an intermediary between the protective cover and the screw, providing a stable positioning surface that guides the screw into the threaded hole. This intermediary structure facilitates easier assembly by reducing the precision requirements for direct hole alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If lock nut is added to bolt, then the securing is improved, but assembly in tight areas is severely limited

Engineering Contradiction:
Improvesecuring strengthVSAvoidassembly space requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the positioning function and the securing function into a single integrated structure (rigid disk with geometric features). This eliminates the need for separate components like lock nuts, maintaining securing reliability while reducing device complexity and space requirements.

Inventive Principle:
Principle #5Merging (Combining)

5Device complexity

If shaft circlips or washers are used, then the structure is simple, but the axial forces of the screw fastening can overcome the securing force

Engineering Contradiction:
Improvestructure simplicityVSAvoidsecuring force
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the mechanism of securing from friction-based (washers, circlips) to geometry-based (rigid disk with positioning features). This provides reliable securing that can resist axial forces without increasing device complexity, as the rigid disk's geometric features inherently prevent screw displacement.

Inventive Principle:
Principle #35Parameter changes

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

Ensures secure, reproducible, and flexible attachment of protective covers to machine parts, preventing screw loss and allowing for easy handling and removal, while maintaining structural integrity and avoiding material overload or brittleness issues.

Implementation Method 1

The security unit includes a rigid disk to support the screw and a resilient strip to make the security unit flexible and to rigidly support the screw

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2278177B1Device preventing loss with a screw and protection device for a machine part
Publication Date: 2016.10.12 HAVER & BOECKER OHG
  • EP2278177B1 patent drawingFigure 1~3
  • EP2278177B1 patent drawingFigure 4A~4D
  • EP2278177B1 patent drawingFigure 5~8

AI summary

The protecting device (1) has a screw (4) for fastening a protective lining (3) e.g. protective cover, to a screw hole (13) of a machine part. A securing device (6) is connected with the protective lining at a connection point (7) or connected to the machine part. The securing device is connected with the screw over a flexible securing unit (8) i.e. elastic strip, to retain the screw at the lining or the machine part. The securing unit is fastened to a screw shaft via a through hole. Smaller free inner diameter of the through hole is smaller than outer diameter of the shaft.