Automated Bag Former With Variable-Pitch Sealing Drum
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Solution Overview
Problem
Existing bag forming processes lack the precision and speed required to consistently produce individual bags from a web material with accurate seal placement, leading to potential faults and inefficiencies in bag production.
Innovation Solution
An automated bag forming system featuring a rotatable drum assembly with variable-pitch sealing assemblies and a computer-based PID feedback loop, which adjusts the working diameter of the drum and position of sealing assemblies for precise seal placement, combined with an optical detection system for real-time adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional bag forming process is used, then the production speed can be maintained at a moderate level, but the precision of seal placement and reproducibility of bag dimensions deteriorate
Solution Approach 1:
The patent implements a feedback control system using an optical detection system to detect registration marks on the web, a drum angle encoder to measure the actual drum rotation angle, and a control system that compares the measured angle with the optimal angle to generate corrective signals. This closed-loop feedback mechanism continuously monitors and adjusts the sealing process to maintain precise seal placement despite variations in web tension, drum speed, or material properties.
Solution Approach 2:
The patent employs a dynamic variable-pitch mechanism where the distance between sealing assemblies can be adjusted during operation. The radially-translatable frame members allow the sealing assemblies to shift radially in response to control signals, enabling real-time adjustment of the effective drum diameter and seal spacing. This dynamic adjustment capability allows the system to adapt to different bag sizes and maintain precision across varying production conditions.
2Productivity
If the drum rotation speed is increased to improve productivity, then the production speed improves, but the precision of seal placement deteriorates due to timing errors
Solution Approach 1:
The feedback control system continuously monitors the drum rotation angle via the angle encoder and compares it with the optimal angle for seal placement. When the web enters the sealing zone, the system detects the registration mark and measures the actual drum angle, then calculates the deviation from the optimal angle and applies corrective radial adjustment to the sealing assemblies to compensate for timing errors caused by high-speed rotation variations.
Solution Approach 2:
The optical detection system detects the registration mark on the web before the sealing operation occurs, allowing the control system to predict the required drum angle and pre-position the sealing assemblies at the correct radial location. This preliminary detection and positioning action ensures that even at high rotation speeds, the seals are placed precisely at the intended locations on the bags.
3Adaptability or versatility
If fixed seal spacing is used to simplify the device, then the device complexity is reduced, but the adaptability to different bag sizes and the precision of seal placement deteriorate
Solution Approach 1:
The variable-pitch mechanism uses radially-translatable frame members that can dynamically adjust the spacing between sealing assemblies during operation. Each sealing assembly is independently controllable, allowing the system to adapt to different bag sizes and seal spacing requirements. The dynamic adjustment is achieved through controlled radial movement of the frame members, enabling flexible configuration without requiring multiple fixed-spacing drums.
Solution Approach 2:
The control system integrates multiple functions into a single unified controller that manages drum rotation, monitors registration marks, measures drum angle, calculates optimal seal positions, and controls radial adjustment of sealing assemblies. This multi-functional control system replaces what would otherwise require separate mechanisms for each function, achieving adaptability to different bag sizes while minimizing overall system complexity through functional integration.
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 system enables high-speed production of bags with precise seal placement and reproducible dimensions, significantly reducing faulty bags by allowing for quick adjustments and precise control over seal placement.
Implementation Method 1
The seal bar can be heated to a temperature necessary to seal the web in a specified location
Implementation Method 2
The drive bar includes a cam follower configured to ride in the sinusoidal groove as the rotatable drum rotates to cause the drive bar to shift
Data Source
AI summary
Automated bag forming systems and methods for their use are disclosed. The automated bag forming systems described herein can be configured to receive a web of bag material and produce individual bags through a sealing and cutting process possessing a high degree of speed, precision, and reproducibility.