Servomotor Sheet Deceleration for Knife Folding Accuracy

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Solution Overview

Problem

Conventional knife folding machines face challenges in achieving accurate folding operations without damaging or wrinkling sheets, especially at high processing speeds, due to sheet rebounding and misalignment issues caused by deceleration methods that apply dynamic friction.

Innovation Solution

A knife folding machine equipped with a servomotor-controlled conveyer belt system that decelerates the sheet at a constant acceleration before it reaches the stopper, preventing rebounding and ensuring accurate positioning at the fold point, using sensors and control units to adjust the deceleration start position and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the feed speed of the sheet is increased to improve processing efficiency, then productivity is improved, but the sheet cannot be accurately set at the fold position due to rebounding from the stopper and may be damaged or wrinkled

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidpositioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The deceleration means is activated before the sheet reaches the stopper to reduce its speed in advance. This preliminary deceleration prevents the sheet from rebounding when it contacts the stopper, allowing high-speed feeding while maintaining accurate positioning at the fold position.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The deceleration means acts as an intermediary between the high-speed conveyer belt and the stopper. It gradually reduces the sheet's speed before it reaches the stopper, mediating the transition from high speed to zero speed to prevent rebounding and positioning errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If deceleration means is used to reduce sheet speed before stopping, then positioning accuracy is improved, but the sheet may slip on the feed surface and become misaligned

Engineering Contradiction:
Improvepositioning accuracyVSAvoidalignment accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The deceleration means changes the speed parameter of the sheet gradually rather than abruptly. This controlled parameter change prevents sudden movements that could cause the sheet to slip or become misaligned on the feed surface, maintaining both positioning and alignment accuracy.

Inventive Principle:
Principle #35Parameter changes

3Speed

If conventional deceleration means applying dynamic friction is used, then sheet speed is reduced, but it is difficult to control the position of the sheet during deceleration

Engineering Contradiction:
Improvesheet speedVSAvoidposition control
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The control unit receives information about the sheet's position and speed during deceleration and adjusts the deceleration means accordingly. This feedback control enables precise position control during the deceleration process, ensuring the sheet stops accurately at the fold position without rebounding or misalignment.

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

This solution allows for high-speed processing while maintaining accurate sheet folding, preventing rebound and misalignment, and enhancing the overall precision of the folding process.

Implementation Method 1

The deceleration means decelerate the sheet conveyed by the conveyer belt by applying dynamic friction to the sheet

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a sensor disposed in the middle way of the feed path to detect a passage of the sheet

Methodology Applied
Scientific EffectOptical detection:

Data Source

PatentEP2527279B1Knife folding device
Publication Date: 2016.05.11 HORIZON INTERNATIONAL INC
  • EP2527279B1 patent drawingFigure 1
  • EP2527279B1 patent drawingFigure 2
  • EP2527279B1 patent drawingFigure 3

AI summary

A knife folding machine comprises: a support surface (4) for supporting a lower surface of a sheet (S); a knife blade (5); a pair of folding rollers (6a, 6b) opposed to the knife blade (5) at a fold position with the support surface (4) therebetween. The knife blade (5) is reciprocated between first and second positions by a knife drive unit 7. The first position is away from an upper surface of the support surface, and the second position is adjacent a gap between the folding rollers. The reciprocal movement of the knife blade (5) effects a folding operation every time the sheet S is set at the fold position. The sheet (S) is conveyed to the fold position by the conveyer belt (13). The conveyer belt (13) is driven by a first servomotor (11). The control unit (12) controls the rotation of the first servomotor (11) so as to decelerate the sheet (S) before its abutment against the stopper (14) without its rebounding against the stopper (14).