Warp Pile Fabrics- Produced with the Aid of Wires
In these cosntructuions, frequently referred to as positive warp pile, only one kind of weft is required but at least two series of warp threads, separately beamed and tensioned are essential viz. ground ends and pile ends.
The Former produce with the weft the ground cloth from which pile ends project and in which they are anchored.
To produce a pile, a wire is inserted across the width of the warp into a shed formed only by pile ends.
When the pile ends are subsequently dropped into the bottom shed and interlaced with the weft, they remain dropped over wired as shown in A and B.
Thus the cross sectional dimensions of the wire determine the height of the pile.
After the insertion of a number of picks and wires the wire farthest away from the cloth fell is withdrawn leaving the loops. The withdrawn wire is reinserted at the front, there being between 12 to 50 wires between the point of withdrawl and insertion.
The special mechanism which controls the wire and movement is designed to insert the wires rapidly as fast as it takes to insert a pick of weft, and to withdraw it slowly. the large number of wires between the two points is necessary mainly to prevent the loops being pulled back by the tension on the pile yarn.
The pile may be looped, if the plain are used or cut, if the wire has a cutting blade at its tip end.
Both types are produced in exactly the same way and the difference in the nature of the pile is created only upon the withdrawl of the wire, the plain wire leaving in the cloths upon withdrawl of the loops, while the cutting wire cuts the loops as it is withdrawn thus leaving the cut tufts in the cloth.
It will be noted, that the wire is inserted into the special high shed formed by the pile yarn, simultaneously with the shuttle which inserts the weft into a low shed fromed by the ground ends.
The loop pile fabrics in this system of weaving are produced mainly for upholstry purpose and are known as uncut moquettes. The cut pile effect are used for apparel wear, curtaining or upholstries and are known as velvets or plushes.