Jacquard Loom

Overview

A jacquard loom weaves figured fabric in which the pattern is built directly into the structure: damasks, brocades, tapestry, labels and intricate upholstery. What sets it apart from an ordinary loom is that it controls every warp thread on its own. A plain loom raises warp ends in fixed groups tied to a few shafts; a jacquard can lift any individual end on any pick, so the design repeat can be as large and as detailed as the number of hooks allows.

The pattern lives as data. Each pick of the design says which of the thousands of warp ends must rise, and the loom realises that selection through an electromagnet for every hook. Driving the selection electronically, rather than from the old punched-card chain, lets a design be loaded from memory and changed without rebuilding the loom.

How it works

The selection happens in the Jacquard Head, mounted high above the warp. For each pick the Loom Control sends the design row to driver boards, which energise the Selection Electromagnet of every end that must rise. An energised electromagnet holds its needle so the hook stays in the path of the Lifting Griffe, a frame of knife bars that lifts once per pick; selected hooks are carried up, unselected ones are left behind.

Each hook connects down through the Harness & Healds to a single warp end. A harness cord runs through the comber board to a mail heald carrying one thread, so lifting the hook lifts exactly that end, and a lead lingoe pulls it back down when released. The lifted and lowered ends together open the shed.

Through that shed the Weft Insertion drives a rigid rapier from each side; the giver carries the weft to mid-shed and hands it to the taker, which draws it across. The Reed & Sley then swings its crank-driven sley so the reed packs the new pick firmly against the fell of the cloth. Warp is fed in by the Warp Beam & Let-Off at controlled tension, while the Cloth Take-Up draws the woven cloth away at the rate that sets pick density and winds it on the cloth beam. A main-shaft encoder keeps the head, rapiers, sley and beams all timed to the same weaving cycle.