Stitched pile surface structure and process and system for producing the same

A stitching process for forming a pile surface structure using a stitching apparatus having first and second needles, each needle penetrating a backing at respective needle penetration points, the process including the steps of:

• (a) at positions disposed above the first surface of backing, looping a first and a second stitching thread around respective first and second locations along a pile-forming yarn itself formed from a plurality of filaments;
• (b) using the first and second needles, drawing both the first and the second stitching threads toward and through the backing to cause the pile forming yarn to train over a sinker finger thereby to form a plurality of pile loop elements each having a pile height substantially equal to the finger height H and stitching thread underlaps,
• each pile element having a U-shaped root portion, the stitching thread underlaps holding and constricting each root portion against the first surface of backing, the underlaps forming distended regions on each side of the constriction in the root portions of substantially all of the pile elements;
• (c) placing a strand of binder material against the root portion of the pile element such that the binder strand is held by the underlaps;
• and
• (d) thereafter, applying heat to activate the binder material and thereby place a mass of binder material within the pile surface structure such that substantially all of the filaments in the distended regions in the root portions of substantially all of the pile elements have binder material thereon.

A stitching process for forming a pile surface structure using a stitching apparatus having first and second needles, the process including the steps of:

• (a) at positions disposed above the first surface of backing, looping a first and a second stitching thread around respective first and second locations along a pile-forming yarn itself formed from a plurality of filaments;
• (b) using the first and second needles, forming a plurality of pile elements and stitching thread underlaps that hold each pile element, thereby to form a pile surface structure;
• (c) using the first and second needles, drawing both the first and the second stitching threads toward and through the backing to cause the pile forming yarn to train over a sinker finger thereby to form a plurality of pile loop elements each having a pile height substantially equal to the finger height H and stitching thread underlaps,
• each pile element having a U-shaped root portion, the stitching thread underlaps holding and constricting each root portion against the first surface of backing, the underlaps forming distended regions on each side of the constriction in the root portions of substantially all of the pile elements;
• and
• (d) stretching the pile surface structure in the longitudinal direction by at least two to twenty (2%-20%) percent to tighten the stitching threads holding the pile elements;
• and
• (e) thereafter, applying heat to activate the binder material and thereby to place a mass of binder material within the pile surface structure such that substantially all of the filaments in the distended regions in the root portions of substantially all of the pile elements have binder material thereon.

A stitching process for forming a pile surface structure using a stitching apparatus having first and second needles, the process including the steps of:

• (a) at positions disposed above the first surface of backing, looping a first and a second stitching thread around respective first and second locations along a pile-forming yarn itself formed from a plurality of filaments;
• (b) using the first and second needles, forming a plurality of pile elements and stitching thread underlaps that hold each pile element, thereby to form a pile surface structure;
• (c) using the first and second needles, drawing both the first and the second stitching threads toward and through the backing to cause the pile forming yarn to train over a sinker finger thereby to form a plurality of pile loop elements each having a pile height substantially equal to the finger height H and stitching thread underlaps,
• each pile element having a U-shaped root portion, the stitching thread underlaps holding and constricting each root portion against the first surface of backing, the underlaps forming distended regions on each side of the constriction in the root portions of substantially all of the pile elements;
• and
• (d) applying heat sufficient to shrink permanently the stitching threads;
• and
• (e) thereafter, applying heat to activate the binder material and thereby to place a mass of binder material within the pile surface structure such that substantially all of the filaments in the distended regions in the root portions of substantially all of the pile elements have binder material thereon.