Since to obtain a weave it is necessary that, of all the warp threads, one part rises and another
is lowered at the passage of each plot, it is evident that in the simplest case to obtain a plot
very basic in a loom two healds are sufficient, so that when one rises the other
it lowers and vice versa (“canvas” armor).
The angle created by the series of raised threads with that of the lowered threads constitutes the so-called mouth
of warp or shed, which has a height such as to allow the passage of the previously transported weft
by the shuttle, today by forceps, projectiles and, for certain types of fabrics, by jets of air or water, which increase
the production capacity of the loom considerably.
The comb, made up of a large number of steel plates welded to a metal frame, is made up of
by a series of teeth through which one or more warp threads are passed. The comb
has the purpose of keeping the threads parallel and giving the comb height of the fabric between the first and last thread
to frame. The comb is fixed on the beater case which serves to guide the shuttle or the gripper into the
step and to match the inserted wefts to the part of the already formed fabric.