Wrapping Machine Rotating Ring Weight Reduction

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Solution Overview

Problem

Existing wrapping machines face challenges with high inertia due to heavy components, limiting rotation speed and productivity, and require complex and laborious adjustments for varying film tension and prestretching ratios, leading to suboptimal film usage and tension control, especially at high speeds.

Innovation Solution

The wrapping machine design positions motors on the supporting frame to reduce the weight of the rotating ring, allowing independent control of roller speeds to maintain constant tension and prestretching force, using flexible driving means and feedback control to adjust film unwinding speed and tension dynamically, eliminating the need for a dandy roll and simplifying the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If motors are positioned on the rotating ring to drive prestretching rollers, then film prestretching control is achieved, but the weight of the rotating ring increases and rotation speed is limited

Engineering Contradiction:
Improvefilm prestretching controlVSAvoidrotating ring weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The motors for driving the prestretching rollers are extracted from the rotating ring and positioned on the fixed supporting frame instead. This extraction removes the heavy motor components from the rotating mass, significantly reducing the rotating ring weight and enabling higher rotation speeds while maintaining film prestretching control capability through the fixed motor positioning system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The driving system is segmented into fixed motor units on the supporting frame that independently control each prestretching roller. This segmentation allows each roller to be controlled separately for film tension and prestretching ratio, providing precise operational control without requiring heavy integrated motor systems on the rotating ring.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If complex adjustment mechanisms are used to vary transmission ratio for different film tensions, then film tension control is improved, but device complexity increases and adjustments become laborious

Engineering Contradiction:
Improvefilm tension controlVSAvoidtransmission ratio adjustment mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system employs dynamic control of motor rotation speeds rather than mechanical transmission ratio changes. The fixed motors can independently and dynamically adjust their rotation speeds to control film tension and prestretching ratio, eliminating the need for complex mechanical adjustment mechanisms and making the system adaptable to different film types and product requirements through electronic control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Mechanical transmission ratio adjustment mechanisms are replaced with electronic motor speed control systems. The fixed motors use electrical control to adjust rotation speeds, substituting complex mechanical gear or belt adjustment systems with simpler electronic control that provides the same film tension control functionality without the mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If high rotation speed is achieved by reducing rotating ring weight, then productivity increases, but tension control precision may be compromised

Engineering Contradiction:
Improvewrapping speedVSAvoidtension control precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system incorporates feedback control mechanisms where the rotation speeds of the fixed motors are continuously adjusted based on film tension requirements. This feedback control maintains precise tension control even at high rotation speeds by dynamically compensating for speed variations and ensuring consistent film application quality throughout the wrapping process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Each prestretching roller is driven by an independently controlled motor, allowing separate optimization of rotation speeds for tension control and productivity. This segmentation enables precise control of film tension during high-speed operation by independently adjusting each roller's speed to maintain optimal film application conditions.

Inventive Principle:
Principle #1Segmentation

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 design significantly increases rotation speed, optimizes film usage, and maintains constant tension during high-speed wrapping, reducing film breakage and improving productivity by allowing rapid and precise adjustments to prestretching force and tension, enhancing the overall efficiency and quality of the wrapping process.

Implementation Method 1

an unwinding and pre-stretch unit arranged for unwinding and stretching or elongating the film made of plastics. The unwinding and pre-stretch unit is provided with a pair of prestretching rollers comprising a slow and a fast roller, respectively upstream and downstream of the movement of the film, to stretch and unwind the extendible film

Methodology Applied
Scientific EffectPrestretching force: Mechanical Force

Implementation Method 2

The prestretching force enables the thickness of the film to be reduced significantly (typically from approximately 25/23 μm to approximately 6/7 μm) so as to increase the length thereof proportionally

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The unwinding and pre-stretch unit is provided with an electric motor, for example an alternating-current, direct-current or brushless electric motor, which motor is also supported by the reel-holding carriage and is able to rotate one of the two prestretching rollers that act as driving (master) roller

Methodology Applied
Scientific EffectElectric motor rotation: Linear Motor

Implementation Method 4

which roller is typically the fast roller that via a belt transmission unit or cog transmission unit drives the other prestretching roller that acts as a driven (slave) roller

Methodology Applied
Scientific EffectBelt transmission: Pulley

Data Source

PatentEP2463202B1Wrapping machine
Publication Date: 2014.04.02 AETNA GRP SPA
  • EP2463202B1 patent drawingFigure 1
  • EP2463202B1 patent drawingFigure 2~3
  • EP2463202B1 patent drawingFigure 4~5

AI summary

A wrapping machine for wrapping a product (2) with a plastic film (3) comprises, supporting frame means (4) with which ring means (10) is associated that rotates around a wrapping axis (Z) of said film (3) around said product (2) and supports carriage means (6) arranged for supporting a reel (7) of said film (3) and for supporting a first roller (22) and a second roller (23) for unwinding and stretching said film (3), first motor means (25) and second motor means (26) fixed to said supporting frame means (4) and coupled respectively with said first roller (22) and said second roller (23), driving means (28, 29, 35, 36) for coupling said first motor means (25) and said second motor means (26) respectively with said first roller (22) and with said second roller (23), said driving means comprising flexible driving means (28, 29, 35, 36) that includes a first driving belt (28) and a second driving belt (29) rotated respectively by said first motor means (25) and by said second motor means (26) and acting respectively on a first driven belt (35) and on a second driven belt (36) arranged for rotating respectively said first roller (22) and said second roller (23).