Weft Detection in Air-Jet Loom Reed Passage
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Solution Overview
Problem
Existing weft detecting devices for air-jet looms are costly and have durability issues due to the use of multiple light-sensitive elements, which are vulnerable to vibrations and impacts during the weaving process.
Innovation Solution
A weft detecting device that incorporates a reflective photoelectric sensor with a light projector and receiver, positioned to detect the weft within the reed passage, using the light amount level of reflected light to determine the weft's position relative to the reed passage, reducing the need for multiple sensors and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light-sensitive elements are used to detect weft position, then detection precision is improved, but device cost increases and durability decreases
Solution Approach 1:
The single light-sensitive element is divided into multiple detection regions (first detection region and second detection region) along the depthwise direction, allowing position detection in different zones without requiring multiple separate sensors. This maintains detection precision while reducing the number of physical sensors needed.
Solution Approach 2:
The single light-sensitive element is designed to perform multiple detection functions by detecting light from different directions (first direction and second direction) corresponding to different depth positions. This multi-functional design eliminates the need for multiple specialized sensors, reducing cost and improving reliability.
2Adaptability or versatility
If multiple light-sensitive elements are mounted in the reed passage region, then weft position detection capability is enhanced, but the device complexity increases
Solution Approach 1:
The detection space is segmented into different depthwise regions, with each region detected by a specific direction of light detection from the single sensor. This virtual segmentation achieves comprehensive coverage without adding physical complexity.
Solution Approach 2:
The single light-sensitive element detects light from multiple directions (first direction and second direction) corresponding to different depth positions. By utilizing the directional dimension, the sensor achieves three-dimensional detection capability without requiring multiple sensors arranged in space.
3Measurement precision
If light-sensitive elements are positioned to detect weft through the reed passage, then detection accuracy is improved, but vulnerability to reed vibration impacts increases
Solution Approach 1:
The patent introduces a light field as an intermediary medium between the sensor and the weft. The light-sensitive element detects light that has interacted with the weft at different depth positions, rather than directly contacting or being physically close to the weft path. This indirect detection method maintains accuracy while reducing vulnerability to mechanical vibrations and impacts.
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 configuration allows for accurate and cost-effective detection of the weft's position, enhancing durability and reducing errors in weft insertion, while also simplifying the system by eliminating the need for separate sensors to estimate fully-strained timing.
Implementation Method 1
The light receiver receives reflected light that has been reflected by the weft
Implementation Method 2
The reflective photoelectric sensor includes a light projector and a light receiver
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A weft detecting device for an air-jet loom includes a main nozzle, an auxiliary nozzle, a reed including a plurality of dents, a reflective photoelectric sensor, and a determination unit. The dents each include a guide recess, and the guide recesses define a reed passage. The main nozzle and the auxiliary nozzle eject air to insert a weft through the reed passage. The reflective photoelectric sensor is located at a position that allows for detection of the weft . The reflective photoelectric sensor includes a light projector and a light receiver. The light projector emits light. The light receiver receives reflected light that has been reflected by the weft. The determination unit is configured to determine a position of the weft relative to the reed passage in a depthwise direction based on a light amount level of the reflected light.