Rollstock Support Spool for Non-Uniform Bag Thickness
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Solution Overview
Problem
Automatic bagging machines struggle to handle rollstock of bags with non-uniform thickness, leading to uneven winding and telescoping issues, which prevents the use of bottom-gusseted pouch-style bags in fully automated systems, requiring manual handling and reducing efficiency.
Innovation Solution
A rollstock support spool with a hollow core and opposed rims, combined with an unwinder assembly that includes a drive motor and photoeye height monitor, ensures uniform winding and constant web height during bagging, accommodating bags of varying thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rollstock of bags with non-uniform thickness is wound onto a conventional spool, then the spool structure is simple, but the rollstock winds unevenly and telescoping occurs
Solution Approach 1:
The spool is segmented into three functional parts: a central hub for mounting, multiple radially extending arms that provide structural support and spacing, and an outer peripheral surface for rollstock contact. This segmentation allows each component to perform its specific function, ensuring uniform winding while maintaining structural integrity.
Solution Approach 2:
The invention transitions from a simple cylindrical spool to a multi-dimensional structure with arms extending in the radial direction. The arms create a three-dimensional framework that provides both structural support and precise spacing, preventing telescoping while accommodating non-uniform bag thickness through the vertical spacing between arms.
2Ease of manufacture
If a simple spool is used for rollstock support, then the device is easy to manufacture, but it cannot maintain uniform rollstock height during unwinding
Solution Approach 1:
The spool is divided into a hub and multiple arms, where the arms are positioned at specific intervals to maintain consistent rollstock height. This segmented design is easier to manufacture than a solid cylindrical spool, as the arms can be attached separately to the hub using standard fastening methods.
Solution Approach 2:
The invention changes the geometric parameters of the spool by introducing arms with specific lengths, spacing, and radial distances from the hub. These parameter variations enable the spool to maintain uniform rollstock height while remaining manufacturable using conventional processes.
3Reliability
If manual handling is used for bags with non-uniform thickness, then telescoping can be prevented, but automation and productivity are reduced
Solution Approach 1:
The spool structure performs the telescoping prevention function automatically through its geometric design. The arms provide fixed spacing that self-regulates the rollstock winding, eliminating the need for manual intervention while maintaining full automation capability for high-volume bagging operations.
4Device complexity
If a conventional spool is used, then the device complexity is low, but it cannot accommodate bags of varying thickness without telescoping
Solution Approach 1:
The segmented spool design with hub and arms provides adaptability to non-uniform bag thickness. The arms create vertical spacing that accommodates thickness variations, while the overall structure remains relatively simple and can be manufactured using conventional processes.
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
Enables the efficient and automated filling of bags with non-uniform thickness, reducing manual intervention and increasing bagging capacity by maintaining a uniform rollstock height and preventing telescoping, thus enhancing the operational efficiency of automatic bagging machines.
Implementation Method 1
a photoeye height monitor that generates signals that are fed back to control the motor to maintain the height of the web of bags essentially constant during bagging
Data Source
AI summary
A rollstock support spool supports rollstock formed from a continuous web of bags of non-uniform thickness along their length. The spool has a hollow core and first and second opposed rims. The hollow core has opposed axial ends, an inner peripheral surface defining a tubular opening configured for mounting over a spindle, and an outer peripheral surface configured to support the rollstock. The rims are located at or near the first and second ends of the core, respectively. A radial spacing between the outer peripheral surface of the core and the outer peripheral surface of each of the rims is greater than a maximum thickness of the rollstock. Also provided are an unwinder assembly incorporating such a rollstock support spool and an automatic bagger incorporating such an unwinder assembly.