Patent ID: 11952682
Assignee: CANDIANI S.P.A.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC D | IPC D

Claim 0:
1. A method for making an elastic core yarn comprising the steps of:
prearranging a source of an elastic core comprising an elastic fiber made of a natural rubber containing more than 80% of cis-1,4-polyisoprene, wherein said elastic fiber has an elastic fiber linear mass density set between 200 dtex and 1000 dtex;
prearranging at least one covering yarn comprising cotton at a weight percentage higher than 50%, wherein said covering yarn has a covering yarn linear mass density set between 6 Nm and 100 Nm, said covering yarn prearranged with an initial twist direction selected between “Z” and “S”;
conveying said elastic core and said covering yarn up to a collecting spool, at a predetermined elastic core conveying speed and at a predetermined covering yarn speed, respectively, wherein:
said elastic core conveying speed ranges from an initial elastic core conveying speed, at said source of elastic core, to a final elastic core conveying speed at least twice said initial elastic core conveying speed, at said collecting spool, and
wherein said step of conveying is carried out in such a way that said covering yarn laterally attains a proximity of said elastic core in a wrapping space; and

helically wrapping said covering yarn about said elastic core in said wrapping space, thus obtaining said elastic core yarn;
wherein:
said elastic core conveying speeds and said covering yarn conveying speed are selected in such a way that, in said step of helically wrapping:
said covering yarn becomes twisted with a final twist direction opposite to said initial twist direction;

a number T of coils of said covering yarn set between a predetermined minimum value T0 and a predetermined maximum value T1, said minimum and maximum values T0,T1 depending upon said covering yarn linear mass density, is wrapped about one length unit of said elastic core yarn, and
said wrapping space is a protected space enclosed by a container.