Trapezoidal Corrugation Roller Train Reducing Web Stress
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Solution Overview
Problem
Conventional corrugating machines struggle to produce trapezoidal corrugations in webs due to the introduction of excessive stress and structural damage caused by sharp edges on the corrugating rollers, resulting in inferior quality layered cardboard structures compared to those with sinusoidal corrugations.
Innovation Solution
A roller train with four corrugating rollers, each set having teeth with progressive geometries that progressively impart trapezoidal corrugations to the web, minimizing stress by using rounded and flattened distal faces and edges to reduce friction and tension, allowing the web to follow specific paths through interlaced nips to achieve trapezoidal corrugations without material stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional corrugating rollers with sharp edges are used to produce trapezoidal corrugations, then the corrugation shape is achieved, but excessive stress and structural damage are introduced to the web
Solution Approach 1:
The corrugating process is divided into multiple stages using a roller train with four rollers, each having teeth with progressively different geometries. The first pair produces initial corrugations, the second pair refines them, and the third pair finalizes the trapezoidal shape. This segmentation allows gradual transformation of the web shape, minimizing abrupt stress changes that would occur with a single-stage process using sharp-edged rollers.
Solution Approach 2:
Different regions of the corrugating rollers have different tooth geometries tailored to specific functions. The first rollers have teeth optimized for initial corrugation formation, while subsequent rollers have teeth optimized for shaping and refining. Each roller's tooth profile is locally optimized to reduce stress concentration at edges while achieving the desired trapezoidal shape in the web.
2Object-affected harmful factors
If sinusoidal corrugations are used to minimize stress, then web structural damage is reduced, but the strength and adhesion of the layered cardboard structure deteriorates
Solution Approach 1:
The invention changes the geometric parameters of the corrugations from sinusoidal to trapezoidal by controlling the tooth profiles of the corrugating rollers. Specifically, the teeth are designed with rounded distal faces and flattened leading and trailing flanks, which transforms the corrugation shape while controlling stress distribution. This parameter change enables the web to achieve both reduced stress and enhanced structural strength.
Solution Approach 2:
The distal faces of the corrugating roller teeth are designed with rounded geometries rather than sharp edges. This curvature at the critical interfaces where the web contacts the rollers reduces stress concentration and prevents structural damage to the web during corrugation, while still achieving the desired trapezoidal shape through the combination of rounded distal faces with flattened flanks.
3Object-affected harmful factors
If a roller train with four corrugating rollers is used to produce trapezoidal corrugations, then stress and friction are reduced, but device complexity increases
Solution Approach 1:
The corrugating function is segmented across four rollers arranged in a train, with each roller contributing a specific stage of the corrugation process. This segmentation distributes the mechanical action over multiple contact points, reducing the stress and friction concentration that would occur with a single roller, while the modular nature of the roller train allows for manageable complexity through repetition of similar components.
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 effectively produces trapezoidal corrugations with reduced stress and friction, enhancing the strength and adhesion of the corrugated web, leading to a more rigid and resistant cardboard structure compared to sinusoidal corrugations.
Implementation Method 1
As the web is drawn through the corrugating labyrinth it is forced to conform to the configuration thereof, thus introducing into the web flutes or corrugations
Implementation Method 2
Corrugating a web in this manner can introduce a substantial amount of oscillatory frictional and tension forces to the web leading into and while traversing the corrugating nip
Implementation Method 3
The distal faces of each of the first and second sets of teeth are rounded. The distal faces of each of the third and fourth sets of teeth are flattened
Data Source
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AI summary
An apparatus for introducing transverse trapezoidal corrugations into a traveling web is provided, and includes a plurality of corrugating rollers for imparting corrugations to the web. In disclosed embodiments four such rollers are provided in a roller train defining respective first, second and third nips therebetween, wherein the teeth of the first and second rollers have rounded distal faces and those of the third and fourth rollers have flattened distal faces. Methods of yielding a trapezoidal corrugated web also are disclosed.