Feeding Gripper Inertial Thread Control for Shuttleless Looms
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Solution Overview
Problem
In rapier weaving machines, the high-speed movement of bringer rapiers can cause weft threads to continue moving at transfer points, leading to picking errors as the threads leave their intended position due to inertial forces, especially with heavier threads, making it difficult for taker rapiers to grasp them securely.
Innovation Solution
A bringer rapier equipped with a thread clamp and a guiding/holding device that utilizes inertial forces to control and move a mass, allowing for precise guidance and holding of the weft thread, ensuring it is securely transferred to the taker rapier by activating a resilient guiding element and mass, which can be movable and arranged on both sides of the rapier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bringer rapier moves at high speed during weft insertion, then productivity is improved, but the weft thread continues to move at the transfer point due to mass inertia, causing picking errors
Solution Approach 1:
The guiding and holding element is positioned and configured to preemptively counteract the inertial movement of the weft thread before it can cause picking errors at the transfer point. By applying this preliminary opposing action, the system prevents the thread from running ahead while maintaining high insertion speeds
Solution Approach 2:
The guiding and holding element is designed to be movable rather than fixed, allowing it to dynamically adapt to the changing conditions during weft insertion. This dynamic configuration enables the element to effectively control the weft thread at different phases of the insertion cycle, maintaining both speed and accuracy
2Measurement precision
If a controlled thread brake is provided to decelerate the weft thread, then thread position control is improved, but the inertial forces stretch the thread elastically after the brake, causing it to leave its intended position
Solution Approach 1:
The guiding and holding element is positioned upstream of the transfer point to establish proper thread tension and position before the thread reaches the critical transfer zone. This preliminary positioning action prevents the need for aggressive braking that would cause elastic stretching
Solution Approach 2:
The guiding and holding element acts as an intermediary between the thread brake and the transfer point, providing gradual thread control that eliminates sudden deceleration. This intermediate control mechanism prevents elastic stretching while maintaining precise thread positioning
3Reliability
If the thread clamp and guiding/holding element are arranged at a distance from one another, then the weft thread can be held on both sides of the receiving rapier, but the device complexity increases
Solution Approach 1:
The guiding and holding element is designed to perform multiple functions: it guides the weft thread during insertion, holds the thread at the transfer point, and ensures proper positioning for the receiving rapier. By making this single element multi-functional, the system achieves reliable thread transfer without proportionally increasing complexity
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 enhances the reliability of thread transfer, minimizing the risk of thread advancement and overstretching, allowing for precise and secure transfer even at high speeds, reducing the need for a controlled thread brake and ensuring consistent tension on both sides of the receiver clamp.
Implementation Method 1
a guiding and/or holding device for guiding and/or holding the weft thread with a guiding and/or holding element and a mass, the guiding and/or holding element being activated by inertial forces that occur when the bringer rapier is accelerated or decelerated
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The feeding gripper (1) has a thread clamp (4) for clamping a weft thread, and an auxiliary guiding and/or holding device (10) for guiding and/or holding the weft thread by a feeding and/or guiding element (5) and has a mass (6). The guiding and/ or holding elements are guided and/or moved by the inertia force of the mass by the acceleration or deceleration of the feeding gripper. An independent claim is also included for a method for guiding and holding a weft thread in feeding gripper.