Connecting Element Tensioner Reset Using Spring Preload

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing screw tensioning devices require high forces to move components relative to each other, especially when the fluid chamber is vented, making it difficult for operators to shift the engagement element into a reset or starting position, which affects operability and operational safety.

Innovation Solution

A device with a reset unit preloads the engagement element relative to the support element, using a connecting ring and disc springs to apply a preload force, facilitating easier positioning of the engagement element into its reset position and reducing the effort required by operators, while ensuring proper alignment and reducing frictional forces from seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If seals are provided between movable components to ensure leak-tightness of the fluid chamber, then reliability is improved, but high forces are required to move the engagement element relative to the support element, worsening ease of operation

Engineering Contradiction:
Improveleak-tightness of fluid chamberVSAvoideffort to move engagement element
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A reset unit with a spring element is provided to pre-load the engagement element in the retracted position before hydraulic actuation. This preliminary action ensures that when the piston moves during reset, the engagement element is already biased toward retraction, reducing the force needed to overcome seal friction and move the component back to starting position.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring element in the reset unit acts as a counterforce mechanism that opposes the frictional forces generated by the seals. By providing this counteracting force, the operator's effort to move the engagement element is significantly reduced, especially when venting the fluid chamber during reset operations.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Ease of operation

If the engagement element is moved relative to the support element during reset, then operability is improved, but high frictional forces from seals increase the required operator effort, worsening ease of operation

Engineering Contradiction:
Improveability to reset deviceVSAvoidoperator effort required
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The reset unit applies a preliminary preload force to the engagement element via the spring element, positioning it favorably before the reset operation begins. This reduces the additional force the operator must apply during the actual reset movement, making the operation easier despite the presence of frictional seals.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring element acts as an intermediary mechanism between the hydraulic system and the engagement element. It mediates the force transmission by storing and releasing elastic energy to assist in moving the engagement element through the seals, reducing the direct force requirement from the operator.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If strong seals are used to prevent fluid leakage, then reliability is improved, but the device complexity increases due to additional sealing components

Engineering Contradiction:
Improvefluid chamber seal integrityVSAvoidnumber of sealing components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The piston serves multiple functions: it acts as both the hydraulic actuator for moving the engagement element and as part of the sealing system for the fluid chamber. By integrating these functions, the patent reduces the number of separate sealing components needed while maintaining reliable fluid containment during high-pressure operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The preload force assists in setting the device into its reset state, reducing operator effort and improving operability, while ensuring proper positioning and increasing operational safety by counteracting frictional forces and enhancing the device's usability in applications like steel constructions and engine design.

Implementation Method 1

a reset unit comprising a spring element configured to exert a preload force onto the engagement element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3898103B1Device for tensioning a connecting element
Publication Date: 2024.01.24 CATERPILLAR ENERGY SOLUTIONS
  • EP3898103B1 patent drawingFigure 1
  • EP3898103B1 patent drawingFigure 2

AI summary

The present invention refers to a device (10) for tensioning a connecting element (12) fastened to a component (18, 20) to be tightened. The device (10) comprises an engagement element (24) connectable to the connecting element (12), and a support element (40) configured to support the device (10) against the component (20) and to translationally guide the engagement element (24) relative to the component (18, 20). Further, the engagement element (24) is preloaded relative to the support element (40).