Protective Shield with Moveable Cut-to-Length Knife
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Solution Overview
Problem
Free-cutting tools experience reduced cutting capacity due to wear of flexible plastic cutting filaments, leading to noise generation from excessive filament length and the need for manual readjustment, which can cause operator error and discomfort.
Innovation Solution
A protective shield with a moveable cut-to-length knife that automatically adjusts the cutting filament length by pivoting between a rest and cutting position, utilizing impact energy from the filament to cut it to the nominal radius, reducing noise through increased spacing during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cut-to-length knife is mounted at the peripheral end of the cutting circle with the cutting edge extending perpendicularly to the cutting circle, then the cut-to-length function is effective, but an unwanted high level of noise is generated during operation
Solution Approach 1:
The cut-to-length knife is made movable relative to the cutting circle through a spring mechanism, allowing it to dynamically adjust its position between being inside and outside the cutting circle. This dynamic positioning resolves the contradiction by enabling the knife to be inside the cutting circle only when needed for cutting, and outside during normal operation to minimize noise.
Solution Approach 2:
The cut-to-length knife operates periodically rather than continuously - it enters the cutting circle only when the cutting filament requires length adjustment, and remains outside otherwise. This periodic action pattern allows the system to maintain effective cut-to-length function when needed while minimizing noise generation during the majority of operation time.
2Reliability
If the cutting filament is manually readjusted to compensate for wear, then the cutting capacity is restored, but operator error and discomfort occur
Solution Approach 1:
The system performs self-service through the automatic cut-to-length function that continuously monitors and adjusts the cutting filament length without operator intervention. The spring-loaded knife automatically engages when the filament becomes too long and cuts it to the correct length, eliminating the need for manual readjustment and associated operator discomfort.
Solution Approach 2:
The system incorporates implicit feedback through the spring mechanism that responds to the length of the cutting filament. When the filament exceeds the nominal radius, it contacts the knife and triggers automatic cutting. This feedback loop maintains cutting capacity without requiring operator judgment or manual intervention.
3Reliability
If the cutting filament becomes shortened due to wear, then the cutting capacity is reduced, but the filament requires readjustment to maintain nominal radius
Solution Approach 1:
The cut-to-length knife provides continuous monitoring and adjustment of the cutting filament length, ensuring the cutting capacity is maintained without interruption. Rather than requiring periodic manual intervention, the automatic system continuously keeps the filament at the correct length, eliminating downtime and maintaining productive operation.
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 automatic and precise cutting to length without manual intervention, reducing noise and operator error, while maintaining the cutting capacity and comfort during operation.
Implementation Method 1
The excessively long cutting filament impacts upon the cut-to-length knife in the rest position and moves this knife into the cutting position as a consequence of the impact energy
Implementation Method 2
The cutting filament aligns itself approximately radially to the rotational axis as a consequence of the developed centrifugal forces
Data Source
AI summary
A protective shield (2) is provided for a free-cutting tool (1). The free-cutting tool has a cutterhead (4) rotatable about a rotational axis (3) and carries a cutting filament (5). For a rotating cutterhead (4), the cutting filament (5) rotates in a rotational direction (10), aligns itself approximately radially to the rotational axis (3) and defines a cutting circle (6) having a constructively pregiven nominal radius (R). The cutting radius (6) is at least partially covered by the protective shield (2). A cut-to-length knife (7) having a cutting edge (8) for cutting the cutting filament (5) to length is mounted on the protective shield (2) in the peripheral region thereof. The cut-to-length knife (7) is mounted on the protective shield (2) to be moveable back and forth between a cutting position (11) and a rest position (12). The cutting edge (8) lies in the plane of the cutting circle (6) in the cutting position (11) and has the nominal radius (R) to the rotational axis (3) and, in the rest position (12), the cutting edge (8) lies outside of the cutting circle (6).