Gear Roll Pitching for Uniform Stretchable Sheet Drawing
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Solution Overview
Problem
The existing gear drawing method for producing stretchable sheets often results in uneven stretchability due to the interaction between the gear roll teeth and embossed sections on the raw sheet, leading to drawing irregularities and locally varying stretchabilities.
Innovation Solution
A method and apparatus using gear rolls with teeth arranged at a specific pitch relative to the embossed sections, where the arrangement pitch of the teeth is greater than the formation pitch of the embossed sections but less than twice that length, to ensure even development of stretchability by minimizing the impact of embossed sections during the drawing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gear drawing is performed on a raw sheet with embossed sections, then stretchability is developed in the raw sheet, but drawing irregularity occurs and stretchability becomes uneven due to the interaction between gear roll teeth and embossed sections
Solution Approach 1:
The invention changes the geometric parameters of the gear roll teeth, specifically setting the tooth height h to satisfy 0.05Pe < h < 0.5Pe where Pe is the embossed section formation pitch. This parameter optimization ensures that the teeth can effectively engage with and draw the fibrous material between embossed sections without causing drawing irregularities, thereby achieving uniform stretchability development across the entire sheet surface.
Solution Approach 2:
The invention optimizes the dynamic interaction between the rotating gear roll teeth and the stationary embossed sections by controlling the tooth height within the specified range. This creates an optimal drawing mechanism where the teeth dynamically engage and pull the material through the embossed regions, transforming the static embossed pattern into a dynamic drawing process that produces uniform stretchability.
2Productivity
If the arrangement pitch of gear roll teeth is too small relative to embossed section formation pitch, then drawing effectiveness increases, but the risk of drawing irregularity and sheet damage increases
Solution Approach 1:
The invention establishes an optimal parameter range for tooth height h where 0.05Pe < h < 0.5Pe. This parameter change balances drawing effectiveness with sheet protection: the teeth are tall enough to effectively engage and draw the fibrous material between embossed sections, yet not so tall that they cause excessive stress concentration or damage to the sheet structure.
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
This approach reduces damage to the sheet and achieves even stretchability across the produced sheet, preventing irregularities and improving the integrity of the stretchable sheet.
Implementation Method 1
the raw sheet is deformed into a shape bent at three points by the teeth of the upper and lower gear rolls that mesh with one another so as to draw the raw sheet in the direction of rotation of the gear rolls
Implementation Method 2
the raw sheet having a plurality of recessed sections formed by pressing
Data Source
AI summary
In a method of producing a stretchable sheet using a pair of gear rolls each having a plurality of teeth arranged on a circumference thereof, a raw sheet is drawn by passing the raw sheet through a gap between the pair of gear rolls. The raw sheet contains a plurality of types of fibers, and has a plurality of recessed sections formed by pressing. The recessed sections are formed collinearly at least along the drawing direction at a predetermined formation pitch in the drawing direction. An arrangement pitch of the teeth in the drawing direction is greater than the formation pitch and smaller than twice the formation pitch.