Paper Towel Cutting Roller With Cam-Guided Knife Carrier
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Solution Overview
Problem
Existing paper towel dispensers struggle to reliably cut paper webs due to varying paper strength and elasticity, often causing the knife to fail to penetrate or resulting in incomplete cuts, especially when the paper is strong or elastic.
Innovation Solution
A knife guide system with a carrier that moves along a non-circular cam track and sliding guide within the cutting roller's slot, ensuring precise pivoting and maximum penetration depth, utilizing a double non-parallel guidance mechanism to maintain smooth operation and reduce play, with a serrated knife edge for enhanced cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the knife is toothed to enhance cutting ability, then the cutting performance on strong or elastic paper is improved, but the knife may fail to penetrate the paper web and only tear off from the roller
Solution Approach 1:
The knife carrier is equipped with a tensioning element that tensions the paper web before the knife reaches it. This preliminary tensioning action ensures the paper web is properly positioned and tensioned, preventing the knife from tearing off the roller without penetrating the paper, thus resolving the contradiction between cutting reliability and harmful tearing effects
Solution Approach 2:
A tensioning element is introduced as an intermediary between the knife and the paper web. This intermediary component prepares the paper web by tensioning it before cutting, ensuring reliable penetration of the toothed knife while preventing the harmful effect of the knife tearing off without cutting the paper
2Ease of operation
If the knife moves in an arc of a circle through the slot, then the knife is guided through the slot, but the carrier pivots about an axis causing uneven movement and reduced cutting precision
Solution Approach 1:
The guidance system is segmented into two independent guidance elements: a first guidance element that guides the carrier in the slot direction, and a second guidance element that prevents pivoting about the axis. This segmentation allows precise control of the knife movement, eliminating the unwanted pivoting while maintaining ease of guidance through the slot
Solution Approach 2:
The guidance system operates in multiple dimensions: the first guidance element controls movement along the slot axis, while the second guidance element constrains rotational movement about the axis. This multi-dimensional guidance approach achieves both ease of operation and high cutting precision by controlling movement in different spatial dimensions
3Productivity
If the knife is extended and retracted in the first part of the roller rotation, then cutting action is provided, but the knife must remain retracted in the remaining second part to avoid damage and ensure smooth operation
Solution Approach 1:
The knife carrier operates with periodic action, being extended during the first part of the roller rotation to perform cutting, and automatically retracted during the remaining second part. This periodic extension and retraction cycle allows continuous cutting action while protecting the knife, achieving high productivity without excessive device complexity through rhythmic, predictable movement patterns
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 ensures reliable cutting of paper webs by tensioning the paper web effectively, allowing the knife to penetrate deeply and maintain cutting performance even with strong or elastic papers, and prevents paper crumpling by managing tension and friction, ensuring clean cuts and reduced waste.
Implementation Method 1
by means of a non-circular, device-fixed cam track is controlled to move in and out through the slot
Implementation Method 2
The sliding guide in the slot of the roller extends essentially parallel to the slot and essentially from the inside to the outside. The guide surfaces can be flat or curved.
Implementation Method 3
Therefore, the further guide surface can preferably also have a tooth system, in which a toothed area of the carrier engages. This not only reduces the play in the two guides
Implementation Method 4
the knife edge can easily carry out a movement leading the roll circumference, since the exit angle of the Messers changed, although the carrier is in one piece
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The guide has a rotatable cutting roller (1) over which a paper web is guided, and a cutter (5) arranged at a carrier (7) that is movable within the cutting roller. The cutter is guided by a non-circular device-fixed cam track (10) so that the cutter is moved through a slit of the roller over a part of rotation of the roller for cutting the paper web. A displacement guide (12) is formed in the slit, and the carrier circulates in the cam track during rotation of the roller and is guided in the displacement guide.