Intermittent Feed Device for Web Print Pitch Alignment
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Solution Overview
Problem
Existing intermittent feed devices for superposing webs in bag making apparatuses face challenges in aligning print patterns due to minor errors in print pitches, requiring either heat application or large slide roller mechanisms, which are unfavorable or impractical.
Innovation Solution
An intermittent feed device with sensors, feed rollers, and a parallelogram linkage that uses tension rollers to correct print pitches by stretching the web with the shorter pitch, ensuring alignment without heat or large slide rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heat is applied to stretch the web to correct print pitch, then print pitch correction is achieved, but the web may be damaged or the process becomes unfavorable
Solution Approach 1:
The patent replaces the thermal field (heat application) with a mechanical field (tension application). Instead of using heat to stretch the web and correct print pitch, the invention applies mechanical tension through tension rollers to achieve the same stretching effect, thereby avoiding web damage from heat while maintaining print pitch correction capability
Solution Approach 2:
The patent changes the physical state parameter from thermal (temperature) to mechanical (tension). By applying tension force instead of heat, the web can be stretched to correct print pitch variations without the harmful effects of thermal processing, thus resolving the contradiction between achieving precision and avoiding damage
2Manufacturing precision
If slide rollers are used to stretch the web for print pitch correction, then print pitch alignment is improved, but a large slide roller drive mechanism is required
Solution Approach 1:
The patent extracts the essential function of print pitch correction from the complex slide roller drive mechanism. Instead of using a large, complex mechanism to stretch the web, the invention uses simple tension rollers that apply tension directly to the web, thereby achieving the same correction function with minimal device complexity
Solution Approach 2:
The patent replaces the expensive and complex slide roller drive mechanism with simple, inexpensive tension rollers. These tension rollers perform the necessary function of stretching the web to correct print pitch without requiring a large drive mechanism, thus resolving the contradiction between achieving precision and reducing device complexity
3Manufacturing precision
If a parallelogram linkage is used to maintain web alignment, then positional relationship is preserved, but the linkage is only applicable when a wide web is slit into webs
Solution Approach 1:
The patent makes the tension roller system universal by enabling it to function with any web configuration (single wide web or multiple slitted webs). The tension rollers can be positioned to engage with the web at any location, making the alignment correction capability applicable to both wide webs and slit webs, thus resolving the contradiction between precision and versatility
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
Effectively aligns print patterns of two webs with different print pitches by applying tension through a biasing member, ensuring accurate superposition and correction of print pitches without the need for heat or large drive mechanisms.
Implementation Method 1
a biasing member for biasing the first tension roller and the second tension roller via the parallelogram linkage to apply tension to the first web and the second web
Implementation Method 2
at least a web with a shorter print pitch of the first web and the second web is stretched by the tension generated by the biasing member such that the print pitch of the first web and the print pitch of the second web are aligned with each other
Data Source
AI summary
Webs include print patterns repeated at print pitches. The first web is intermittently fed at the print pitch of the first web by a first pair of feed rollers to a section. The second web is fed at the print pitch of the second web by a second pair of feed rollers to the section. The first web and the second web are fed in a superposed state by a downstream pair of feed rollers from the section. A first tension roller and a second tension roller engaging with the first web and the second web are biased by a biasing member via a linkage.