Folding Roll Suction Hole Arrangement for Wrinkle Reduction
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Solution Overview
Problem
Existing paper folding machines suffer from delays in suction due to atmospheric pressure in longitudinal channels, leading to wrinkles and reduced productivity, and parallel-oriented suction holes fail to control sheet release accurately, resulting in suboptimal folding quality.
Innovation Solution
A folding roll with suction groups comprising intersecting close longitudinal rows of suction holes, arranged to intersect at specific angles, allowing for precise control of sheet adhesion and release, enhancing vacuum distribution and reducing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If longitudinal channels are used to distribute vacuum, then vacuum can be distributed to multiple suction holes, but a delay occurs in suction activation due to atmospheric pressure in the channels
Solution Approach 1:
The patent extracts and eliminates the intermediate longitudinal channels that cause delay. Instead of using channels to distribute vacuum, the invention connects suction holes directly to the vacuum source through a bell distributor, removing the atmospheric pressure barrier that causes activation delay.
Solution Approach 2:
The bell distributor is pre-configured with multiple suction holes positioned at different angular locations, allowing immediate suction activation when vacuum is applied, without waiting for pressure equalization through channels.
2Manufacturing precision
If parallel-oriented suction holes are used, then the roll structure is simple, but sheet release accuracy is poor resulting in wrinkles
Solution Approach 1:
The patent applies asymmetry by arranging suction holes in incident planes that intersect at specific angles rather than in parallel orientations. This asymmetric angular arrangement enables precise control of sheet adhesion and release, preventing wrinkles while maintaining structural feasibility.
Solution Approach 2:
Different suction holes are positioned at specific angular intervals to create localized suction zones. This allows differential control of sheet adhesion at different locations, enabling precise sheet release timing and preventing wrinkles through localized quality variation.
3Productivity
If high-speed operation is implemented, then productivity increases, but folding accuracy decreases due to insufficient sheet control
Solution Approach 1:
The intersecting incident planes of suction holes create periodic suction zones as the roll rotates, providing rhythmic adhesion and release cycles that maintain precise sheet control even at high operating speeds, ensuring folding accuracy is preserved.
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 high-speed operation with improved folding accuracy and quality by ensuring synchronized sheet release and adhesion, reducing wrinkles and enhancing the final product's quality.
Implementation Method 1
a suction roll (1), in particular a folding, or interfolding, roll, providing a particular arrangement of the suction holes, which connected to a vacuum generation system, cause the sheet, or web, of paper to adhere on the roll surface
Data Source
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AI summary
A roll (1) for folding, or interfolding, a web, or sheet, of paper, (100) fed along an advancing direction in a paper converting machine, or similar machines, comprises a tubular body (10) configured to rotate about a longitudinal rotation axis (101), and having an external lateral surface (11) and an internal lateral surface (12) pneumatically communicating through a plurality of suction holes (3a, 3b) organized in a predetermined number of suction groups (60). Each suction group (60) comprises a predetermined number of close longitudinal rows (30a, 30b) of suction holes (3a, 3b) distributed along the tubular body (10). A suction chamber (20) is, then, provided arranged internally to the roll (1) for folding, or interfolding, and pneumatically connected to a suction device generating a predetermined vacuum level. Each suction group (60) comprises at least 3 close longitudinal rows (30a, 30b, 30c) of suction holes (3a, 3b, 3c) configured to hold each sheet, or web, of paper (100) on the roll (1) at a respective portion of the external lateral surface (11).