Web Conveying Apparatus for Diaper Crotch Crease Prevention
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Solution Overview
Problem
In the manufacturing process of pants-type disposable diapers, the non-continuous crotch portions tend to contract towards the continuous waistline portions, leading to creases and defects when the web is conveyed from one apparatus to another, especially at the leg-surrounding portions with leg gathers.
Innovation Solution
A web conveying apparatus with a hold mechanism that stretches the crotch portions away from the waistline portions and a conveying mechanism that hands over the web to downstream apparatuses while maintaining the crotch portions' alignment, preventing contraction and creases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suction belt is used to attract the web to prevent contraction, then the web can be held stable during conveyance, but the web gets away from the belt conveyor at handover locations causing creases and defects
Solution Approach 1:
A guide member is introduced as an intermediary component between the suction belt and the downstream apparatus. The guide member extends in the width direction of the web and guides the web from the suction belt to the downstream apparatus, preventing the web from getting away and causing creases at handover locations
Solution Approach 2:
The guide member is configured as a thin, flexible component that can adapt to the web's position while maintaining guidance. This thin film structure allows the guide member to follow the web's contour and prevent creases without interfering with the suction belt's holding function
2Device complexity
If the web is conveyed without restrictions, then the conveyance process is simple, but the non-continuous crotch portions contract towards the waistline portions causing creases
Solution Approach 1:
The guide member acts as a simple intermediary structure that prevents web contraction and creases without adding complex control systems. It maintains web flatness through its physical presence as a guiding element rather than through active control mechanisms
Solution Approach 2:
The guide member changes the physical parameters of the web conveyance path by providing a fixed geometric reference in the width direction. This geometric constraint prevents the web from contracting sideways while maintaining conveyance simplicity
Data Source
AI summary
A web conveying apparatus configured to convey a pair of webs folded in the cross direction CD with reference to a folding line. The web conveying apparatus includes a crotch hold bar configured to hold an intermediate web in a conveyable manner with the folded intermediate web stretched in a direction in which the crotch portions get away from the waistline portions; and a conveying mechanism configured to convey the intermediate web and hands over the intermediate web to a joint apparatus and a cutting apparatus, while the crotch portions are being held by the crotch hold bar.