The rapier loom weaves through the weft insertion of the rapier head and rapier belt. The rapier head and rapier belt are the core components of the rapier loom. This chapter introduces the rapier head, and the next chapter introduces the rapier strap.
1. The function of the rapier head
The rapier head is a main device for completing the weft insertion movement in the rapier loom. It consists of two parts: the weft sending sword and the weft receiving sword. They are installed on two swords respectively. The top end of the belt performs reciprocating motion in the sword walking plate (guide rail) through the sword belt driving device.
The weft-feeding sword clamps the weft yarn sent from the weft selection finger from the left side of the loom, and introduces it into the center of the loom shed. The weft-feeding sword moves from the right side of the loom to the center of the loom, and sends the weft-feeding sword. The weft yarn is hooked and returned to the selvedge on the right side of the shed. The weft-feeding sword also returns to the left side of the shed. The weft-feeding sword completes the first cycle of weft insertion task, and the reed starts beating up.
2. Conditions that the rapier head should meet in terms of weaving technology
(1) Appearance of the rapier head.
①The surface of the sword head should be smooth, without waste edges, burrs, cracks, depressions and bubbles, and there should be no weft breaks.
② The warp yarn contact surface should be smoothly connected, and the yarn passing surface should not have any defects that may lead to yarn breakage.
(2) The weft-feeding sword must work stably and reliably. The crimping plate must be well matched with the contact surface on the left housing. The height of the head of the crimping plate must ensure that various weft yarns are accurately included in the jaws and can be clamped reliably. The weft yarn should not be detached or broken.
(3) The meshing working surface of the weft connecting sword yarn clamping rod and the yarn hooking head should be smooth without burrs, matched and opaque, and open flexibly to ensure reliable weft yarn clamping.
(4) The size of the gap between the yarn guide support arm of the weft sword and the metal head of the yarn hook should be determined according to the thickness of the yarn, generally controlled at 0.3 ~ 1.2mm, to ensure that each yarn can enter smoothly.
(5) The weight of the rapier head should, in principle, be determined during the overall structural design of each type of rapier loom. The weights of several commonly used rapier heads are shown in Table 13-1 for reference.
(6) The rapier head should have good wear resistance and long service life, so as to minimize the user’s machine material consumption, the selection of materials, the accuracy of the processing technology, and the accuracy of the heat treatment and surface treatment technology. Adjustment is crucial to the service life of the sword head.
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