Air Jet Loom Weft Insertion Control via Sensor Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In air jet looms, it is difficult to effectively control the air injection of sub-nozzles using weft yarn arrival timing detected by a sensor at an intermediate position, due to the influence of air injection from the main nozzle and the braking mechanism, which affects the stability and efficiency of weft yarn insertion.
Innovation Solution
An air jet loom with a weft insertion control device that includes a weft middle sensor at an intermediate position to detect the weft yarn arrival timing, allowing for the adjustment of sub-nozzle air injection timings to match varying weft yarn traveling conditions, thereby optimizing weft insertion and reducing compressed air consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photoelectric sensor is disposed at an intermediate position in the weft passage to detect weft yarn arrival timing, then the timing detection capability is improved, but it becomes difficult to effectively control the air injection of sub-nozzles due to the influence of main nozzle air injection and braking mechanism
Solution Approach 1:
The patent divides the weft passage into multiple zones with different sensor positions. Specifically, it places a first sensor (S1) upstream and a second sensor (S2) downstream of the brake position, segmenting the detection function to capture weft yarn timing at different stages of traversal, thereby enabling effective control of sub-nozzle air injection despite the complex influences in the passage.
Solution Approach 2:
The patent introduces a microcomputer-based control system as an intermediary that processes timing signals from the sensors and automatically adjusts the air injection timing of sub-nozzles. This intermediary device mediates between the sensor detection and the sub-nozzle control, resolving the difficulty of direct manual control while maintaining precision.
2Productivity
If the traveling speed of weft yarn is increased to improve productivity, then the efficiency of air jet loom operation is improved, but the shock applied to the weft yarn at the end of insertion increases causing yarn breakage
Solution Approach 1:
The patent applies preliminary braking action to the weft yarn before it reaches the end of the insertion passage. The brake is positioned upstream and activates the weft yarn earlier in its trajectory, gradually reducing its speed before the high-speed impact zone, thereby preventing yarn breakage while maintaining high overall traveling speed for productivity.
Solution Approach 2:
The patent implements dynamic speed control of the weft yarn through the braking mechanism, which adjusts the yarn's velocity profile along its path. The brake creates a dynamic deceleration zone that adapts to the yarn's speed, allowing high initial speeds for productivity while ensuring safe deceleration to prevent breakage at the insertion point.
3Reliability
If a brake is applied to the weft yarn before the end of insertion to prevent yarn breakage, then the reliability of weft insertion is improved, but it becomes difficult to figure out the influence of sub-nozzle air injection on weft yarn traveling condition
Solution Approach 1:
The patent segments the measurement function by placing multiple sensors at different positions - one upstream of the brake and one downstream. This segmentation allows independent measurement of weft yarn timing in different zones, enabling the system to isolate and measure the specific influence of sub-nozzle air injection on yarn traveling condition while the brake maintains reliability.
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 solution enables precise control of sub-nozzle air injection, improving the stability and efficiency of weft yarn insertion by aligning air injection timings with the weft yarn's traveling conditions, reducing the risk of yarn breakage and optimizing compressed air usage.
Implementation Method 1
the photoelectric sensor measures the timing at which a weft yarn reaches the detecting position
Implementation Method 2
the air injection of sub-nozzles that carries the weft yarn in the weft insertion passage significantly influences the stability of the weft insertion
Data Source
Figure 1~2B
Figure 3~4
Figure 5
AI summary
A weft insertion control device in an air jet loom including a weft insertion nozzle (2), a plurality of sub-nozzles (7) and a brake (13) braking a weft yarn (Y) before weft insertion end, wherein the weft insertion control device includes a sensor (18) provided within a width of cloth to be woven by the air jet loom so as to detect the weft yarn (Y) and a correction unit (16) correcting air injection start timing (D1, F1, H1) of the sub-nozzles (7), wherein the sensor (18) is disposed between a leading end position (YE) of the weft yarn (Y) that is located at air injection end timing (ME) of the weft insertion nozzle (2) and a leading end position (YB) of the weft yarn (Y) that is located at brake timing (BT) of the brake (13), and wherein the correction unit (16) estimates a weft traveling curve (A, B, C, E, G) based on weft detection timing (IS) of the sensor (18) and corrects the air injection start timing (D1, F1, H1) of the sub-nozzles (7) in accordance with the estimated weft traveling curve (A, B, C, E, G).