Shuttleless Loom

Overview

A shuttleless loom weaves cloth without the flying shuttle of an old-style loom. The shuttle carried a weft package back and forth across the warp, which limited speed, made noise, and threw a heavy mass twice per pick. Shuttleless looms instead leave the weft package stationary at the side and carry only the thread across, which lets them run faster, quieter, and with far more flexible weft colour changes. The most common type, described here, is the rapier loom, where two slender rapier heads meet at the centre of the shed and hand the weft from one to the other. Rapier looms suit the widest range of yarns and the most frequent colour changes, which is why they dominate fashion fabric, upholstery, and multi-colour goods.

The loom performs the four weaving motions in time. The Shedding Mechanism opens the shed, the Rapier Insertion inserts the weft fed by the Weft Feeder, the Sley and Reed beats it up, and the Warp Let-off and Cloth Take-up advance warp and cloth. A Leno Selvedge Unit unit binds the cut edges, a Main Drive times everything from the main shaft, and a Control System runs the pattern and protects the cloth.

Rapier weft insertion

The Rapier Insertion is the heart of the loom. Two heads work together: the Giver Rapier enters from the supply side, takes the weft tip, and carries it to the middle of the shed, where it hands off to the Taker Rapier that has come in from the far side. The taker grips the weft and draws it the rest of the way across, then both withdraw and the pick is laid. This double-rapier, centre-transfer design keeps each head's stroke to half the width, which allows wide looms at high speed. Each head rides on a flexible toothed Drive Tape driven by a Drive Wheel, and the tapes are supported across the warp by a Rapier Guide so they stay straight. A Transfer Cam times the handover precisely, because a missed transfer drops the weft and stops the loom.

Weft feeding

Because the weft must accelerate to high speed and stop cleanly every pick, it is not pulled straight from the cone. The Weft Feeder sits between package and loom: a Feeder Motor pre-winds weft onto an Accumulator Drum, building a small reserve, and the rapier draws from that reserve instead of from the package. This decouples the violent insertion from the gentle unwinding of the cone, so tension stays even and the package does not snag. A Yarn Brake holds the weft tip between picks, a Weft Tensioner keeps the pick flat, and a Weft Sensor counts wraps and detects a weft break. Looms that weave coloured patterns carry one feeder per weft colour, and the control selects which colour to insert on each pick.

Shedding

The Shedding Mechanism mechanism decides the weave. Each warp end threads a Heddle Wire eye on a Heald Frame, and raising some frames while lowering others opens the shed. The Electronic Dobby is electronic: a Selection Solenoid latches each frame that the stored program calls for, and a pair of Lifting Knife knives lift the latched frames together. With up to sixteen frames the loom weaves fairly complex structures, and a weave can be changed in software rather than by re-pegging a pattern chain. Coil Spring returns pull the frames back down between picks.

Beat-up, let-off, and take-up

After the pick is laid, the Sley and Reed sley swings forward and the Weaving Reed pushes the new weft up to the cloth fell, its motion driven by the Beat-up Cam and Rocking Shaft. The Warp Let-off releases warp from the Warp Beam with a Let-off Servo servo and a Back Rest Roller roller read by a Pressure Sensor, holding warp tension constant as the beam empties. At the front the Cloth Take-up pulls the cloth over a gritted Emery Roller and winds it onto the Cloth Roll, with the Take-up Servo servo setting the picks per centimetre.

Selvedge and edges

A rapier lays a single thread and cuts it at each edge, so unlike a shuttle it does not leave a continuous looped edge. The Leno Selvedge Unit unit makes a firm edge with a Leno Disc that twists two edge ends around each weft to bind it, after which a Edge Cutter trims the weft loop. A Temple holds the cloth out to full width at the fell so it does not draw in, and a Waste Selvedge holds the weft tail during binding and is cut away.

Drive, control, and use

The Main Drive turns the Main Shaft through a Clutch-Brake that stops the loom on an exact pick for clean restarts. The Control System runs the weave and colour program on an Microcontroller, and a Warp Stop-Motion halts the loom the moment a warp end breaks. The operator sets speed and pattern at the Operator Panel. Rapier shuttleless looms cover the broadest market in weaving, handling fine filament dress goods and coarse upholstery, plain and figured, with quick colour and pattern changes that suit short fashion runs. Air-jet and water-jet looms run faster on plain wide goods, but the rapier wins where yarn variety and colour flexibility matter.