Paper Cutter Hydraulic Valve Checking During Press-Cut Cycles

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Solution Overview

Problem

Existing methods for controlling the hydraulic drive of a paper cutting machine do not effectively check the functionality of valves during operation, leading to potential unsafe movements and performance impairments.

Innovation Solution

Implementing a valve check process that activates and monitors the redundant press and clutch valves during the press-cutting cycle, using a safety controller to ensure only properly functioning valves are used, and detecting faults to prevent dangerous movements by switching to the other operational valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant valves are used in the hydraulic system, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvevalve functionalityVSAvoidhydraulic system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary testing of redundant valves by activating them sequentially during the press-cutting cycle. The first valve is tested before the second valve is activated, allowing the system to verify valve functionality in advance and switch to the other valve if a fault is detected, thus maintaining safety without requiring continuous monitoring of all valves simultaneously.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If continuous monitoring of valve functionality is implemented, then safety is improved, but productivity and cycle time are reduced

Engineering Contradiction:
Improvesafe operationVSAvoidpress-cutting cycle time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic testing of valve functionality at specific intervals during the press-cutting cycle rather than continuous monitoring. The valves are tested at predetermined points in the cycle, allowing the machine to maintain full productivity while ensuring safety through regular functional verification of the redundant valves.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If valve testing is performed during operation, then detection precision is improved, but the press-cutting cycle is interrupted

Engineering Contradiction:
Improvefault detectionVSAvoidcycle interruption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the valve testing function with the normal press-cutting cycle operations. The testing of redundant valves is integrated into the existing cycle steps, such as testing the first valve during the press phase before the cutting phase begins. This allows fault detection to occur without requiring separate testing cycles or interrupting the overall productivity of the machine.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3300868B1Method for controlling a hydraulic drive of a pressing bar, and/or a drive of a cutter bar of a paper cutting machine
Publication Date: 2021.01.27 PERFECTA SCHNEIDEMASCHINENWERK GMBH BAUTZEN
  • EP3300868B1 patent drawingFigure 1a
  • EP3300868B1 patent drawingFigure 1b
  • EP3300868B1 patent drawingFigure 2

AI summary

The invention relates to a method for controlling a hydraulic drive of a press beam and/or a drive of a cutter beam of a cutting machine such as a paper cutting machine, wherein in a press hydraulic circuit a fluid such as oil is circulated by means of a first pump via a first press valve and a second press valve connected in parallel to the first press valve, and/or wherein in a cutting hydraulic circuit a fluid such as oil is circulated by means of a second pump via a first coupling valve and a second coupling valve connected in parallel to the first coupling valve, wherein to start a press cycle the first press valve and the second press valve are actuated to generate a pressing pressure in a press chamber of the hydraulic drive to drive the press beam, and wherein to start a cutting cycle the cutting valves are actuated.to generate a pressing force in a hydraulic coupling cylinder coupled to the drive of the cutter bar. To check the functionality of the press and/or cutting valves, it is provided that the press valves and/or the cutting valves are activated with a time delay at the start of the press or cutting cycle and/or deactivated with a time delay at the end of the press or cutting cycle, and that during a test cycle in which only one of the press valves or coupling valves is activated, the occurrence or non-occurrence of an expected reaction is monitored.