Terry Towel Loom

Overview

A terry towel loom weaves the looped pile fabric that gives towels and bathrobes their soft, absorbent surface. The loop, called terry pile, stands up from a base cloth and is what holds water. Making those loops needs a special weaving action that an ordinary loom cannot do, so the terry loom carries two separate warps and a mechanism that builds loops by controlling how far the reed beats the weft home. It is built on a rapier loom base, since the loops form during weaving rather than from any extra cutting or knitting step.

The loop forms from the interaction of three things: the Terry Pile Motion that beats up in groups, the slack Pile Warp Let-off that frees the pile warp, and the firm Ground Warp Let-off that anchors it. Weft is laid by the Rapier Insertion through sheds opened by the Shedding Mechanism mechanism, the Cloth Take-up advances the towelling, the Selvedge and Cutter unit edges it, and a Main Drive and Control System run the towel program.

How the loop is made

Terry weaving runs on a three-pick cycle controlled by the Terry Pile Motion. Two of the three picks are loose picks: the Weaving Reed beats them only part way, stopping short of the cloth fell, so the weft sits a little distance from the cloth. On the third pick, the fast pick, the reed beats fully home, and as it drives that weft forward it pushes the two loose picks along with it the rest of the way to the fell. The pile warp, held slack by the Pile Warp Let-off, cannot resist this push, so it buckles up out of the cloth plane and forms a loop, while the ground warp, held firm by the Ground Warp Let-off, stays flat and locks the loop in place. The Terry Cam sets this cycle, the Loose-Pick Servo sets how far the reed falls short on the loose picks, and a Cloth-Fell Shifter moves the fell back and forth to complete the action. Loop height is simply how far the reed under-beats, so it is adjustable in the program.

The two warps

A terry loom needs two warp beams because the pile and the ground are under different tension. The Pile Warp Let-off holds the Pile Warp Beam at low tension through a Pile Let-off Servo servo and a floating Pile Back Rest, read by a Pressure Sensor, with a Tension Compensating Roller taking up the slack that swings between loose and fast picks. The Ground Warp Let-off holds the Ground Warp Beam at firm normal weaving tension through its own Ground Let-off Servo and Ground Back Rest. The difference in tension between the two warps is exactly what decides which one loops and which one stays flat.

Weft insertion and shedding

The Rapier Insertion inserts weft like any rapier loom: a Giver Rapier carries the weft to the centre and a Taker Rapier draws it across, both riding Drive Tape tapes driven by a Drive Wheel. A Weft Feeder meters weft smoothly from its Accumulator Drum. The Shedding Mechanism mechanism opens the sheds, and on a terry loom it must control the ground and pile frames separately so the two warps interlace correctly. An electronic Electronic Dobby selects the frames with a Selection Solenoid per frame, lifted by a Lifting Knife, which also lets the loom weave plain bands, dobby borders, and a flat hem where the towel will be cut and stitched.

Borders, hems, and edges

A towel is not uniform pile. It has flat woven borders and a flat hem band at each end, woven by suppressing the pile motion in those zones so the fabric is dense and firm for hemming. The Control System programs where pile turns on and off along the length, and the Cloth Take-up coordinates the cloth advance, gripping the looped fabric on a gritted Emery Roller without crushing the pile. The Selvedge and Cutter unit binds the side edges with a Leno Disc and holds the cloth out to width with a ring Full-Width Temple designed not to flatten the loops, and a Fringe Cutter can separate towels at a fringe band.

Drive, control, and use

The Main Drive turns the Main Shaft through a Clutch-Brake for clean pick-accurate stops. The Control System holds the towel recipe, loop height, border layout, and weft colours on an Microcontroller, and a Warp Stop-Motion halts the loom when a ground or pile end breaks. The operator works at the Operator Panel. Terry looms make bath, hand, and kitchen towels, bathrobes, and beach towels, in cotton and cotton blends, with pile on one or both faces and dobby or jacquard borders. The same loop principle, varied in height and density, gives everything from a thin tea towel to a heavy plush bath sheet.