Spring Tension Screw Assembly for Repeatable Barrier Boom Break-Off Force

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Solution Overview

Problem

Existing reusable break-off protection mechanisms for barrier booms face challenges in accurately adjusting and maintaining spring tension due to dimensional tolerances, requiring complex and costly measurement processes, and necessitating qualified staff for recalibration after disassembly.

Innovation Solution

A two-piece special screw assembly with adjustable height, utilizing a screw and nut with defined torque and thread pitch to securely fasten and adjust spring tension, allowing for precise and repeatable tensioning without the need for repeated measurement or adjustment, and enabling easy reassembly by unqualified personnel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If spring stacks are used to achieve high break-off force, then the compressive force increases, but the spring deflection becomes too small and dimensional tolerances cause significant variations in tension force

Engineering Contradiction:
Improvebreak-off forceVSAvoidspring tension consistency
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent transitions from static spring stacks with fixed dimensions to a dynamic adjustment mechanism using an adjusting screw that allows modification of spring precompression. This enables the system to compensate for dimensional tolerances and achieve consistent break-off forces despite variations in spring stack height.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of spring precompression force through an adjusting screw mechanism. By modifying the precompression parameter, the system can compensate for dimensional tolerances in spring stacks and achieve consistent tension forces, resolving the contradiction between force magnitude and precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If complex measurement and adjustment processes are implemented to achieve precise spring tension, then manufacturing precision improves, but device complexity and time requirements increase

Engineering Contradiction:
Improvespring tension accuracyVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a self-adjusting mechanism where the adjusting screw allows direct manual adjustment of spring precompression without requiring complex measurement equipment or specialized tools. The mechanism serves itself by providing an intuitive, tool-free adjustment capability that eliminates the need for sophisticated calibration procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs preliminary adjustment of spring tension during the assembly process using the adjusting screw, before the mechanism is put into service. This preliminary action ensures proper tension is set initially, eliminating the need for complex post-installation measurement and adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If qualified staff are required to perform calibration after disassembly, then manufacturing precision is maintained, but loss of time and operational disruption increase

Engineering Contradiction:
Improvetension calibration accuracyVSAvoidrepair time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The adjusting screw mechanism is designed to be operable by unqualified personnel without specialized tools or knowledge. After disassembly, any person can manually adjust the screw to restore spring tension, eliminating the need to wait for qualified staff and significantly reducing repair time.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs a simple, robust adjusting screw mechanism that is inexpensive and easy to replace if needed. This simple mechanism prioritizes quick replacement and adjustment over long-term durability, allowing rapid restoration of functionality without requiring specialized intervention.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Device complexity

If fixed-length screws are used for spring tensioning, then device complexity is reduced, but manufacturing precision and repeatability of tension adjustment deteriorate

Engineering Contradiction:
Improvescrew assembly simplicityVSAvoidtension repeatability
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces fixed-length screws with an adjusting screw that can be modified in length through threading. This dynamic adjustment capability allows precise control of spring precompression while maintaining relative simplicity of the overall assembly, resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #15Dynamics

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

This solution ensures precise and repeatable spring tension adjustment, reduces the need for specialized tools and staff, shortens repair time, and minimizes costs by allowing quick reassembly and maintenance of barrier booms, even after disassembly due to impacts.

Implementation Method 1

an elastic member adjacent to the ball

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the spring elements are placed in a holder

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

a first relevant tightening of a screw is made with the use of a torque wrench

Methodology Applied
Scientific EffectScrew: Screw

Implementation Method 4

a two-piece special screw assembly with adjustable height, utilizing a screw and nut with defined torque and thread pitch

Methodology Applied
Scientific EffectMechanical Fastener: Mechanical Fastener

Data Source

PatentEP3556940B9Method of permanent adjustment of spring elements tension for use under dynamic load
Publication Date: 2021.09.29 BOMBARDIER TRANSPORTATION ZWUS POLSKA
  • EP3556940B9 patent drawingFigure 1(a)~2
  • EP3556940B9 patent drawingFigure 3(a)~3(c)

AI summary

The invention relates to a method of adjusting the tension of spring elements permanently for use under dynamic load, in particular in reusable ball break off protection mechanisms of a barrier boom break off protection system, characterized by the fact that the spring elements (Item 5) are placed in the holder (Item 3) and the first relevant tightening of the screw (Item 1) is made with the use of a torque wrench, whereas the torque value is defined in beforehand either experimentally or analytically through analyzing the relation between the tightening torque and the tension of the screw and it is equivalent to reaching the height of screwing the screw in that corresponds to the target and peak tension of spring elements and this value is within from 30 to 150 Nm. Then from this value the screw (Item 1) is being unscrewed by the defined number of revolutions in order to maintain the appropriate working stroke of the ball (Item 7) and the washer (Item 6) that are being pressed down by the springs and this working stroke results directly from the characteristics of the piece of equipment in order to enable the unobstructed breaking off of the part (Item 4) of the ball break off protection mechanism. In the end the screw (Item1) is secured against changing its fixed position and against untightening with the use of a special nut (Item 2) thereby creating one, integrated and monolithic special screw.