Tobacco Cutting Apparatus with Dynamic Knife Grinding
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Solution Overview
Problem
Existing methods for cutting tobacco leaves into controlled strand lengths using ribbed or castellated knives are costly due to expensive machining operations, and there is a need for an inexpensive apparatus and process to limit the maximum length of tobacco strands effectively.
Innovation Solution
A cutting apparatus using standard plain knives with a grinder that moves in both parallel and perpendicular directions to the axis of rotation of the cutting drum, allowing for a controlled strand length without the need for expensive machining, and a method involving a grinder with controlled movements to create a castellated or undulating profile on the knives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ribbed or castellated knives are used to limit maximum strand length, then the maximum length of tobacco strands is limited effectively, but the manufacturing cost increases significantly due to expensive machining operations
Solution Approach 1:
The knife is pre-formed with a straight edge using standard manufacturing processes, and the castellated profile is created during operation by the grinder removing material in a controlled manner. This preliminary preparation avoids the need for complex pre-machining of the knife to the final castellated shape.
Solution Approach 2:
A grinder is introduced as an intermediary device that creates the castellated profile on the knife during operation. Instead of machining the complex shape directly into the knife, the grinder acts as a mediator that transforms the simple straight-edged knife into the required castellated form through controlled material removal.
2Ease of manufacture
If standard plain knives are used instead of castellated knives, then the manufacturing cost is reduced, but the maximum strand length cannot be limited effectively
Solution Approach 1:
The system transitions from a static knife geometry to a dynamic profile creation process. The grinder moves relative to the rotating knife, dynamically creating the castellated profile during operation. This allows standard knives to be transformed into effective strand-length-controlling tools through a controlled dynamic process.
Solution Approach 2:
The grinder operates in periodic cycles, advancing along the knife edge and creating castellations at regular intervals. This periodic action of the grinder relative to the rotating knife produces the repeating castellated pattern that limits strand length while using simple standard knives.
3Manufacturing precision
If expensive and accurate machining operations are performed during knife manufacture, then the castellated profile is achieved, but the overall cost of the cutting apparatus increases and replacement parts become less accessible
Solution Approach 1:
The system uses standard, inexpensive knives that can be easily replaced rather than expensive custom-machined knives. The cost of the knife itself is secondary to the cost of the machining operation, so using cheap standard knives that require only simple grinding to create the castellated profile reduces overall system cost and improves parts availability.
Solution Approach 2:
Complex mechanical machining operations are replaced with a simpler grinding process. Instead of using expensive CNC machining or precision milling to create the castellated profile during knife manufacturing, a conventional grinder is used to create the profile through controlled material removal, simplifying the overall manufacturing system.
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 the overall cost of the cutting apparatus and allows for repeatable, reliable cuts with easily obtainable replacement parts, improving the free-flowing nature and uniformity of tobacco strands, enhancing processing and cigarette manufacturing efficiency.
Implementation Method 1
a grinder which is movable relative to the cutting drum and which can be brought into contact with the cutting edge to grind the cutting edge with a movement in a direction substantially parallel to the axis of rotation of the cutting drum and with a movement in a direction substantially perpendicular to the axis of rotation of the cutting drum
Data Source
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AI summary
A cutting apparatus for producing a controlled strand length effect using a tobacco cutting machine fitted with standard, non-profiled knives is disclosed. The cutting apparatus comprises a mouth defined by a jaw assembly for delivering the material to be cut to a cutting position at the mouth and a cutting drum. The cutting drum is provided with a least one knife the, or each, knife having a cutting edge. The cutting drum comprises drive means and is rotatable about an axis arranged substantially parallel to the mouth such that the cutting edge of the at least one knife is arranged substantially perpendicularly to the material to be cut. A grinder is provided for removing material from the cutting edge of the at least one knife, wherein the grinder is configured to be brought into contact with the cutting edge with a movement in a direction substantially parallel to the axis of rotation of the cutting drum and with a movement in a direction substantially perpendicular to the axis of rotation of the cutting drum. The cutting apparatus allows the maximum length of strands of cut tobacco to be limited, by employing standard plain knives combined with a special mode of operation of a cutting machine knife grinding system.