Web Cut-Off Assembly for Accurate Perforation Breaking
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Solution Overview
Problem
Conventional winders often shut down due to web break faults, leading to production losses and the need for repair services, as existing web breaking methods are inefficient and prone to errors such as incorrect perforation line breaks and high torque requirements.
Innovation Solution
A web cut-off system and method using a conveying surface with a web cut-off assembly featuring movable arms with web gripping surfaces that contact the web at specific points to create a controlled break, minimizing strain and ensuring accurate cutting, even at high speeds and varying web tensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two rotary paddles are used to create strain and break the web, then the web can be broken at the perforation, but the paddles are relatively far apart causing the sheet to break at wrong perforation lines or different locations
Solution Approach 1:
The web breaking function is segmented into multiple contact points along the web width, with each contact point having gripping surfaces that can independently apply strain. This segmentation allows precise control over where breaks occur along the perforation lines while maintaining appropriate spacing between individual gripping elements.
Solution Approach 2:
Different portions of the web experience different strain conditions through the distributed gripping surfaces. The gripping surfaces are positioned to create localized strain zones that correspond to perforation locations, ensuring breaks occur at the correct local positions rather than uniformly across the entire web span.
2Force
If high torque is applied to accelerate paddles within one revolution to create large strain for breaking, then the web can be broken, but the maximum speed of the machine is limited
Solution Approach 1:
The web breaking mechanism transitions from a high-torque, low-speed rotational paddle system to a dynamic, high-speed system where multiple gripping surfaces move with the web at machine speed. The strain is applied dynamically through the relative motion of gripping surfaces rather than through high-torque acceleration, enabling operation at maximum machine speeds without torque limitations.
Solution Approach 2:
The gripping surfaces are positioned and accelerated to match web speed before contact, eliminating the need for high-torque acceleration during the breaking action. The strain is applied through pre-positioned gripping elements that move synchronously with the web, allowing high-speed operation without torque constraints.
3Ease of operation
If the web is conveyed over a long distance between breaking elements, then the breaking mechanism can operate, but web alignment is compromised causing wrinkling and folding
Solution Approach 1:
The web support and breaking function is segmented into multiple distributed contact points along the web width. These segmented gripping surfaces maintain web alignment by providing localized support at each contact zone, preventing wrinkling and folding that would occur with long-span unsupported web sections.
Solution Approach 2:
The gripping surfaces act as intermediary elements between the web and the breaking mechanism. These intermediaries maintain web alignment and tension during the breaking process, preventing instability and misalignment while enabling the breaking operation to proceed effectively.
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 system effectively reduces web break faults by maintaining web alignment and accuracy, minimizing production downtime, and eliminating the need for additional actuation systems, as it applies tension only between the gripping points, preventing wrinkling and ensuring consistent breaks across different web properties.
Implementation Method 1
The first and second web gripping surfaces contact the moving web at a first contact point and a second contact point. The contact points move from a first spaced apart relationship to a second spaced apart relationship causing a break in the web between the first and second contact points.
Data Source
AI summary
A cut-off method and apparatus capable of breaking a moving web is disclosed herein. The cut-off method and apparatus include a conveying surface over which a moving web is conveyed and a web cut-off assembly opposing the conveying surface. The web cut-off assembly includes a first arm with a first web gripping surface and a second arm with a second web gripping surface, the first and second web gripping surfaces being movable relative to one another. To complete a breaking event, the first and second web gripping surfaces contact the moving web at a first contact point and second contact point. The contact points move from a first spaced apart relationship to a second spaced apart relationship causing a break in the web between the first and second web gripping surfaces.