Rotating Disk Weft Cutter for Shuttleless Looms
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Solution Overview
Problem
Existing weft thread cutting devices for shuttleless looms, such as guillotine and scissors types, face challenges with high pressure requirements for resilient yarns and difficulty in cutting fancy or multiple yarns, leading to inefficiencies and increased complexity in controlling the cutting phase.
Innovation Solution
A weft thread cutting device that combines a high-speed rotating disk with split feet and levers, a retaining tooth, and a pitch-controlled motor to cut yarns efficiently, allowing for remote phase variation control and minimizing weft waste, using a control software and proximity sensor to synchronize the cutting action with the loom's cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If guillotine or scissors cutting devices are used, then the cutting mechanism is simple in structure, but high pressure is required for resilient yarns which increases device complexity and control difficulty
Solution Approach 1:
The patent replaces the traditional mechanical guillotine or scissors cutting system with a high-speed rotating disk cutting system. The rotating disk with cutting edges cuts the weft thread through rotational motion rather than linear blade movement, eliminating the need for high pressure between stationary blades and reducing the mechanical complexity of the cutting mechanism.
Solution Approach 2:
The cutting device transitions from a static blade system to a dynamic rotating disk system. The rotating disk can be controlled in terms of speed, direction, and timing, allowing flexible adaptation to different yarn types without requiring high pressure, thus resolving the contradiction between structural simplicity and pressure requirements.
2Reliability
If high-speed rotating blade cutting is used, then cutting effectiveness for resilient yarns is improved, but the device cannot handle fancy yarns or multiple wefts of different types which reduces adaptability
Solution Approach 1:
The rotating disk cutting device is designed with multiple cutting edges and adjustable parameters (speed, rotation direction, disk position) that allow it to effectively cut various yarn types including resilient yarns, fancy yarns, and multiple wefts of different titles. This multi-functional capability resolves the contradiction by making the device universally applicable to different yarn types while maintaining reliable cutting performance.
Solution Approach 2:
The cutting device allows for parameter changes such as rotation speed, disk position, and cutting edge configuration to be adjusted according to the specific yarn type being processed. This flexibility enables the same rotating disk mechanism to reliably cut different yarn types without requiring multiple specialized devices, thus improving both reliability and adaptability.
3Ease of operation
If variable regulation motor with inverter is used, then control flexibility of cutting phase is improved, but the mass of mechanical devices increases which affects system response time
Solution Approach 1:
The patent replaces the heavy variable regulation motor and inverter system with a more lightweight rotating disk mechanism driven by a simpler motor. The cutting phase control is achieved through the rotation dynamics of the disk rather than through complex mechanical regulation systems, reducing the overall mass while maintaining control flexibility through electronic timing control.
4Productivity
If cutting blades are positioned to intercept outgoing weft, then new weft insertion is enabled, but re-entry of inserted weft is blocked which increases device complexity
Solution Approach 1:
The rotating disk cutting device dynamically opens and closes the cutting gap during rotation, creating a timing-based control mechanism. The disk rotates to intercept the outgoing weft for cutting, then opens to allow the inserted weft to re-enter, eliminating the need for multiple control devices and wire guiding mechanisms. This dynamic operation resolves the contradiction by using temporal separation rather than mechanical complexity.
Data Source
AI summary
A weft thread cutting device for shuttleless looms is placed between a fabric edge, a comb and a warp mouth, on one side, and a weft thread selector, on the other side. Weft threads, coming from a plurality of eyelets, join at a vertex located at the fabric edge and at the beating line of the comb. The weft thread cutting device has a rotating disk with a cutting edge, configured to cut the weft threads by a motor which keeps the rotating disk in rotation, and a step control motor, which, through a rotating shaft provided with an eccentric, controls motion of a hinged lever swinging with respect to a longitudinal axis of the step control motor. The hinged lever is shaped, at one end, in the form of two arms, respectively resting on the surfaces of two elastic plates, and is connected, at the other end, to the eccentric.