Hydraulic Sheet Holding Unit for Thickness Variation Stability

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Solution Overview

Problem

Existing sheet holding devices struggle to maintain optimal thrust and calibration due to surface irregularities and thickness variations, leading to poor product quality, tool wear, and apparatus damage.

Innovation Solution

A holding unit with mobile gripping members and a hydraulic actuator system using incompressible fluid to stabilize the sheet position, ensuring uniform holding despite thickness changes and surface irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional gripping members are used to hold the sheet, then the sheet can be held during working, but surface irregularities and thickness variations cause imbalances in thrust leading to poor product quality and tool wear

Engineering Contradiction:
Improveproduct qualityVSAvoidthrust balance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies hydraulic actuation through a piston-cylinder arrangement to control the gripping members. The hydraulic system provides smooth, controlled movement and consistent thrust force, eliminating the imbalances caused by traditional mechanical actuation methods when dealing with sheets of variable thickness or surface irregularities

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent implements adjustable gripping force parameters through the hydraulic system, allowing the thrust magnitude and application rate to be optimized. This enables consistent holding force despite variations in sheet thickness, maintaining both product quality and thrust balance

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If gripping members exert thrust on the sheet to hold it, then the sheet is secured during working, but this causes tool wear, damage to coatings, and sheet breakage

Engineering Contradiction:
Improvesheet position stabilityVSAvoidsheet damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces elastic elements such as springs or elastomeric cushions between the gripping members and the sheet surface. These flexible elements distribute the gripping force over a larger area and absorb peak stresses, preventing damage to the sheet, its coatings, and the working tools while maintaining stable positioning

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The elastic cushioning elements are pre-installed in the gripping members to provide immediate protection against excessive forces. This beforehand cushioning prevents direct rigid contact between the gripping mechanism and the sheet, avoiding damage during the holding operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If stabilizer devices are used to prevent vibrations, then sheet position is stabilized, but it is very difficult to implement predetermined and optimal thrust and calibration values

Engineering Contradiction:
Improvevibration controlVSAvoidthrust calibration
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent incorporates sensors and control systems that monitor the actual gripping force and sheet position in real-time. This feedback enables automatic adjustment of the hydraulic actuation to maintain optimal thrust values, simplifying operation while ensuring consistent vibration control and calibration accuracy

Inventive Principle:
Principle #23Feedback

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 consistent sheet holding, maintaining product quality and extending tool life by absorbing thickness variations and irregularities, reducing vibrations, and preventing apparatus damage.

Implementation Method 1

a feed circuit configured to feed said actuator, wherein said feed circuit comprises: a delivery line and a return line which are fluidically connected to said actuator; a first solenoid valve for the control of said delivery and return lines, wherein said delivery line is configured to feed said actuator with an advantageously incompressible liquid

Methodology Applied
Scientific EffectHydraulic principle: Hydraulic Press

Data Source

PatentEP4577378B1Device and related method for holding a slab
Publication Date: 2026.04.08 FOREL SPA
  • EP4577378B1 patent drawingFigure 1
  • EP4577378B1 patent drawingFigure 2

AI summary

Holding unit (10) for holding a sheet (200) comprising a stabilizer device (11) provided with gripping members (12, 13) of which at least one is mobile with respect to the other along an axis of grip and release (Z) to hold said sheet (200), and a drive unit (14) comprises an actuator (16) associated with the mobile gripping member (12, 13) and a feed circuit (17) configured to feed said actuator (16).