Dispenser comprising a separation unit
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Solution Overview
Problem
Existing dispensers for paper towels face challenges in accurately separating web materials along preformed lines of weakness, particularly when dealing with heavy rolls and varying web material lengths, often requiring strong paper that compromises softness and requiring significant space or electrical power.
Innovation Solution
A dispenser with a separation unit featuring two rollers with protrusion elements arranged in a staggered, overlapping configuration to create an undulating passage that optimizes the pinch force, allowing for accurate and smooth separation of web materials without damaging them, and adjustable settings for different types of web materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If strong paper is used to withstand the force necessary to make a full heavy roll to start rotating, then the roll can be accelerated, but the softness of the paper is low
Solution Approach 1:
The continuous web material is divided into individual sheets by preformed lines of weakness (perforations). This segmentation allows the dispenser to handle lighter individual sheets rather than requiring the entire heavy roll to accelerate at once, reducing the strength requirement while maintaining softness.
Solution Approach 2:
The web material is pre-folded into an accordion-like configuration with preformed lines of weakness before being placed in the dispenser. This preliminary preparation allows the separation unit to easily divide sheets along the perforations without requiring excessive force, thus avoiding the need for strong (hard) paper.
2Quantity of substance
If rolls of paper towels are made heavy to provide sufficient material, then the volume is large, but the dispenser demands a large amount of space
Solution Approach 1:
The web material is folded into a compact accordion-like structure that nests within the dispenser housing. Multiple layers of the web are interfolded and stacked vertically, allowing a large quantity of material to be stored in a reduced volume compared to a traditional horizontal roll.
Solution Approach 2:
The web material is arranged vertically in a stacked configuration rather than horizontally as in traditional rolls. This dimensional change allows the dispenser to utilize vertical space more efficiently, reducing the horizontal footprint while maintaining adequate material quantity.
3Force
If the rollers are positioned close together to create strong pinch force for separation, then the web material can be separated, but the preformed lines of weakness may break prematurely
Solution Approach 1:
The protrusion elements on the rollers have varying sizes and are positioned to create localized pinch points. The separation force is concentrated at specific locations along the web material where the preformed lines of weakness are most vulnerable, allowing effective separation without requiring excessive overall pinch force that would cause premature breaking.
Solution Approach 2:
The rollers are designed with rotating protrusion elements that dynamically engage with the web material during rotation. The pinch force is applied intermittently as the protrusions pass through the web, rather than as continuous static pressure. This dynamic application of force allows separation to occur at the intended location without causing premature breaks.
4Device complexity
If the protrusion elements are arranged in a linear pattern on the rollers, then the structure is simple, but the separation accuracy is reduced
Solution Approach 1:
The protrusion elements on the rollers are arranged in asymmetric, staggered patterns rather than simple linear configurations. This asymmetric arrangement creates multiple pinch points at different positions and angles, improving the accuracy of separation by ensuring that the pinch force is applied precisely at the preformed lines of weakness regardless of minor variations in web material positioning.
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 solution enables precise and efficient separation of web materials, minimizing the force required for separation while preventing premature line breaks, and is adaptable for various web materials and lengths, ensuring effective operation without the need for electrical power.
Implementation Method 1
Each of said protrusion elements has a maximum width in said width direction, a maximum radial extension from said rotational axes, an inner portion adjacent to said rotational axes, and an outer portion remote from said rotational axes. The outer portions of the protrusion elements on said first roller are arranged in a staggered relationship with the outer portions of the protrusion elements on said second roller.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3
AI summary
The present invention provides a separation unit for separating a web material along preformed lines of weakness. The separation unit has a width direction and comprises a first roller having a rotational axis extending in the width direction and a web width extending in the width direction, and a second roller having a rotational axis extending parallel with the rotational axis of the first roller and a web width extending in the width direction. The second roller is positioned at a distance from the first roller, the distance extending in a direction perpendicular to the width direction. Each of the first and the second rollers is provided with a plurality of protrusion elements being spaced along the rotational axes and protruding perpendicular from the axes. Each of the protrusion elements has a maximum width in the width direction, a maximum radial extension from the rotational axes, an inner portion adjacent to the rotational axes, and an outer portion remote from the rotational axes. The outer portions of the protrusion elements on the first roller are arranged in a staggered relationship with the outer portions of the protrusion elements on the second roller such that the outer portions of the protrusion elements on the first roller are partially overlapping with the outer portions of the protrusion elements on the second roller with a radial overlap length, thus forming an undulating passage for a web material between the rollers. Each protrusion element has a maximum width along the width direction within the overlap length, and the sum of the maximum widths within the overlap length of all protrusion elements on one of the rollers is between 5-30%, preferably 12-20% of the web width of that roller.