Giver Rapier Head Spacing Control for Double Weft Insertion
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Solution Overview
Problem
Existing bringer rapier heads fail to maintain the spacing between two weft threads during double weft insertion, leading to twisting and poor fabric quality, while also limiting the ability to implement a pic-à-pic system without stopping the machine.
Innovation Solution
A bringer rapier head with a first guide device for the first weft thread and a second guide device for the second weft thread, where the second guide device is closed to maintain distance and can be independently actuated to allow for pic-à-pic selection, using a split clamping lever to decouple the gripper clamp and clamping plate movements, ensuring the second weft thread is not released until the rapier head has left the shed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the second guide device is closed to maintain distance between weft threads, then low-twist double weft insertion is achieved, but pic-à-pic system cannot be implemented
Solution Approach 1:
The second guide device is designed to be dynamically switchable between closed and open states. During weft insertion, it remains closed to maintain spacing and prevent twisting. During color changes, it can be opened to allow different weft threads to be threaded through, enabling pic-à-pic system functionality without compromising spacing maintenance during operation.
Solution Approach 2:
The guide device is configured to maintain the spacing of weft threads in advance before insertion into the shed. By pre-establishing the correct spacing position through the closed guide device, the system ensures that weft threads are properly positioned for low-twist insertion while still allowing color changes to be prepared in advance by opening the guide device during idle periods.
2Adaptability or versatility
If the guide device is opened to allow color changes, then pic-à-pic system is enabled, but spacing between weft threads is lost
Solution Approach 1:
The guide device transitions from a static closed state to a dynamic system that can open and close as needed. This allows the spacing function to be activated only when required (during weft insertion) while permitting color changes when the device is opened, resolving the contradiction between maintaining precision and enabling versatility.
3Device complexity
If weft threads are introduced without maintaining spacing, then device complexity is reduced, but fabric quality deteriorates due to twisting
Solution Approach 1:
The guide device is segmented into separate components: a closed guide portion that maintains spacing and an opening mechanism that allows color changes. This segmentation enables the system to maintain spacing functionality without requiring an overly complex integrated structure, while still ensuring fabric quality through consistent spacing maintenance during weft insertion.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a giver rapier head (4) for a rapier loom with double weft insertion, said loom having a first guide device (2) and a second guide device (3) for respective weft threads (7, 8), wherein the two guide devices (2, 3) are arranged at a distance from one another on the front end, in the insertion direction of the weft threads (7, 8), of the giver rapier head (4). The first weft thread (7) is guided in the first open guide device (2), and the second guide device (3) for the second weft thread (8) has a clamping plate (6) to keep it closed. The weft threads (7, 8) are clamped in a yarn clamp (1) during weft insertion. The yarn clamp (1) can be brought, by means of an actuating device (9), from a clamping position into an open, non-clamping position, and the clamping plate can be brought, by means of the actuating device (9), into an open position, not closing the second guide device (3). The actuating device (9) operates the yarn clamp (1) in a double function, either decoupled from the movement of the clamping plate (6) to transfer the weft thread (7, 8) from the yarn clamp (1) or together with the clamping plate (6) to release the second weft thread (8) from the second guide device (3), wherein the times of the release of the particular weft thread can be adjusted. The invention further relates to a rapier loom for double weft insertion with a giver rapier head as described above and to a method for weft insertion by means of a rapier loom with the features described above.