Shearing is a process that involves cutting and homogenizing the surface fur of the fabric at a certain height. It is normally carried out in dry conditions and on almost all fabrics. Her intensity varies from the complete excision of the superficial filaments to a simple blurring of the
The fabric passes in succession, through a tensioner (see figure A, point 1), a metal detector
(fig. A, 2) and a center piece (fig. A, 3), dragged by cylinders, some in neutral and others driven. Two
spreading cylinders (fig. A, 4), perfectly stretch the pieces and avoid creases and swellings
before access at the velvety point (fig. A, a), where they are found
a cylindrical brush (fig. A, 5) with adjustable speed, which straightens the hair with steel tips
flexible, and a movable wedge bar (fig. A, 6), which controls the approach of the fabric to the brush
and at the cutting point (fig. A, b) where a metal cloth holder (figs. A and B, 7), always wedge-shaped,
keeps the fabric stretched close to the group
trimmer, whose distance from the fabric, adjustable, determines the length of the hair.
The pruning unit (fig. B) which is the most important part of the pruning machine, consists of:
a rotating shearing cylinder (figs. A and B, 8 and fig. 8, detail), called male, which according to
of its own diameter, can accommodate from 16 to 32 hardened steel helical blades placed on
an adjustable blade, called knife (fig. B, 9 and fig. 9, detail), as long as the cylinder and locked
on the appropriate support (fig. B, 10).
The helical blades of the pruner cylinder, in contact with the underlying fixed blade (knife) create
a contrasting point of hair cut. When the pruning cylinder has made the turn, the blade
with the propeller fixed there, he cut the hair from one selvedge to another. The helical blades can be
wound on the cylinder from right to left or vice versa. The direction of the propellers on multi-cylinder toppers
it is alternated to avoid deviations of the piece and stabilize it in the center.
The hair produced with the topping is removed by an aspirator (fig. A, 12).
A pneumatic lifter (fig. A, 11) intervenes at the passage of the end of the seam.
In addition to the velvety machine and topping groups, there are:
horsehair-coated brushes (fig. A, 13); particularly important is the one placed before the group
trimmer which, acting on the reverse side, removes any threads or fibers from the surface of the fabric;
feelers, which actuate the lifting of the cylinders when seams pass wide;
a thick felt soaked in a special oil that rests on the trimming cylinder, which keeps the helical threads and the fixed blade efficient longer;
a series of dragging cylinders, which bring the pieces to the welder.
The pruning machine configurations can include: 1) single machine; 2) multiple machines in line; 3)
machines arranged on a chain of different processes (for example raising and topping).
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