Experience: How to avoid wear and tear on the rapier head and strap of a rapier loom?

The rapier loom is a type of shuttleless loom, which is a universal loom for weaving small and medium-sized fabrics with frequent variety changes. During the production process, the rapier loom uses high-speed weft insertion, and the consumption of the rapier head and rapier belt accounts for more than half of the total material consumption of the rapier loom. Therefore, it is crucial to avoid wear and tear on the rapier head and strap in order to save production costs.

1. The hazards of wear and tear

The rapier head and rapier belt are key components for weft insertion in rapier looms. During the weft insertion process of the rapier loom, the weft yarn is always actively controlled by the rapier, resulting in smaller weft insertion errors and higher reliability. Once the rapier head is worn, it can lead to weft insertion failure, and in severe cases, there may even be a large number of broken ends in the warp yarn, affecting the quality of the fabric.

The parts of the sword head that are prone to wear and tear are the head, wings, and bottom. Every time the weft is inserted, the rapier head is subjected to friction from the warp, rapier guide hook, rapier plate, and guide rail when entering and exiting the rapier. When the two wings of the rapier head are severely worn and form a knife like shape, it is easy to cause warp breakage, and even without the control of the guide hook, the rapier head can jump out of the shuttle, causing a large number of breakage.

2. Reasons for wear and tear

Practice has found that most of the damage to the rapier head is caused by fracture damage caused by the collision between the weft sending rapier head and the weft receiving rapier head. This situation is due to the gap formed by long-term wear and tear between the transmission device and the rapier belt, causing the rapier head to deviate.

The wear of the rapier head in a rapier loom is also closely related to the variety of weaving. The wear and tear of the rapier head varies greatly among different varieties. For fabrics with coarse yarn count and high warp density, the rapier is severely worn and has a short service life. However, the service life of the rapier head in chemical fiber products is relatively short. This is because the rapier head rubs back and forth on the synthetic warp yarn, generating static electricity, causing a layer of hardened material to condense at the bottom of the rapier head, making it easy to hang the warp yarn.

The composition of the sizing material used for warp sizing also has a significant impact on the wear of the rapier head, and different sizing components have different effects on the wear of the rapier head.

The process structure of a rapier loom is also related to the wear of the rapier head, especially the higher the height of the back beam, the greater the tension at the bottom warp, and the more severe the wear of the rapier head. Due to the high tension of the lower warp yarn, as the shed gradually closes, the lifting force of the lower warp yarn on the supporting rapier head correspondingly increases, and the squeezing friction force on the rapier guide hook is greater, resulting in greater wear on the rapier head.

The transmission between the rapier belt and the rapier wheel of a rapier loom is a special type of belt transmission: the rapier belt has rectangular holes. During the transmission process, there is meshing transmission between the tooth root and the wall of the rapier hole, and friction transmission between the rapier belt and the inner surface of the rapier wheel; The meshing angle between the sword belt and the sword wheel is usually 120 ° to 180 °. When the pitch is equal, there is no relative sliding between the sword wheel and the sword belt, and the pitch line velocity is equal. When the sword wheel swings, it forms a reciprocating linear motion of the sword belt. Due to the rigidity of the flexible composite belt, the sword belt needs to withstand a certain bending stress during bending. Therefore, an arc-shaped pressure plate is designed to move the sword belt closer to the surface of the sword wheel. However, the use of the arc-shaped pressure plate greatly increases the friction force between the rear half of the sword belt, making it thinner.