Variable Speed Bag Transport for Cross-Bottom Welding
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Solution Overview
Problem
The throughput of bag making systems is limited by the cyclical operation and fixed repeat distance between tubular bag bodies, leading to inefficient use of processing stations and energy wastage in hot air welding devices, especially with smaller bag widths.
Innovation Solution
A device and method that adjust the feed distance and speed of bag bodies during transport to set a predefined distance between successive bag bodies, allowing for variable repeat lengths and optimizing the use of processing stations, including hot air welding, by using a transfer device with controlled movement and holding mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transport speed of bag bodies is increased to improve throughput, then productivity increases, but the performance limits of cross-bottom forming equipment and hot-air welding equipment are exceeded
Solution Approach 1:
The patent introduces variable speed sections in the transport line, allowing different segments to operate at different speeds. The feed section operates at a higher speed to reduce spacing between bag bodies, while processing sections maintain optimal speeds for their operations, creating a dynamic speed profile that optimizes both throughput and equipment performance
Solution Approach 2:
The transport line is divided into multiple independent speed-controlled sections: a feed section for reducing spacing, processing sections for bottom formation and welding, and an output section. Each section can be independently controlled to optimize its specific function while contributing to overall throughput improvement
2Productivity
If a fixed repeat distance is used between bag bodies, then the system is simple to operate, but the transport potential is not fully exploited and processing stations run idle
Solution Approach 1:
The repeat distance between bag bodies is changed from fixed to variable, allowing optimization of spacing based on bag width and processing requirements. The system dynamically adjusts the feed distance to minimize idle time at processing stations while maintaining operational simplicity through automated control
Solution Approach 2:
The system uses sensors to detect bag body positions and widths, and the control unit automatically calculates and adjusts the feed distance to optimize spacing. This feedback mechanism ensures that processing stations are fully utilized without requiring manual intervention to maintain optimal repeat distances
3Loss of energy
If the distance between successive bag bodies is large, then there is sufficient space for processing operations, but energy is wasted and throughput is reduced
Solution Approach 1:
The spacing between bag bodies is dynamically optimized to be as small as possible while still allowing processing operations. The variable speed feed section reduces the distance between successive bag bodies to minimize the idle time of hot-air welding devices and reduce energy wastage, while the processing sections maintain adequate working space
4Productivity
If cyclical operation is used to process bag ends, then the system is simple to control, but the throughput is limited by the cycle time
Solution Approach 1:
The patent transitions from cyclical batch processing to continuous processing, where bag bodies are constantly fed through the system at optimized speeds. The variable speed control and automated positioning enable continuous operation without the stop-start nature of cyclical processes, significantly improving throughput while the control unit manages the complexity of coordinating multiple speed variations
Data Source
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AI summary
A device (1) for producing bags from tubular bag bodies (10) comprises a transport device (2) that transports the bag bodies in a flat position transverse to their longitudinal extent (L) at a transport speed (V) in a transport direction (T). During their transport, the bag bodies pass through processing stations (30, 40, 50, 60, 70, 80) in which at least one end region (13) of each bag body is formed into a cross bottom and optionally a cover sheet (19) is applied to the cross bottom. The bag bodies preferably have a fabric made of stretched plastic strips or a plastic film or composites of the fabric and plastic films and may be coated with polymer.A transfer device (4) moves the bag holders (10) to be transported by the transport device with a transfer speed (U) by a feed distance (Δy) in the transport direction (T) relative to bag holders transported at transport speed (V) and then transfers them to the transport device (2).