The present invention relates to a device for lubricating the weft
thread for weaving looms.
It is known that in high-speed weaving processes performed with modern
shuttle-less air jet looms, projectile looms, and the like, the weft thread is
unwound from the spool by a weft pre-feeder interposed between the spool and the
loom which accumulates a reserve of thread in the form of turns that unwind from
the feeder when requested by the loom.
In many cases, in order to achieve perfect insertion of the weft
between the warp threads, it is necessary, due to the high beating rates of the
loom, to lubricate the weft thread to eliminate, or at least reduce, the sliding
friction of said weft on the warp threads. Weft lubrication also allows to obtain
a thread that is more uniform and consequently can be better processed, is less
subject to jamming and therefore to breakage, and can be handled more easily by
the pre-feeder too, since lubrication generally facilitates sliding and attenuates
sudden variations in the sliding speed caused by localized friction variations.
Normally, the thread is lubricated when it is taken from the spool to be woven
immediately, with vegetable low-viscosity oils or mixtures of oils, and the treatment
must be performed in such a manner to ensure uniform lubrication despite the thread
unwinding speed, avoiding both excessive and insufficient impregnation.
The principal aim of the present invention is to provide a lubrication
device that can provide, industrially and without using labor, the lubrication
of the weft thread when taken from the spool with the above-mentioned uniform
treatment methods, regardless of the unwinding speed of said thread and of any
Another object of the invention is to provide a lubrication device
having an extremely simplified structure, being highly reliable in operation, and
A further object of the invention is to provide a lubrication device
requiring an occasional monitoring substantially aimed at merely restoring the
level of the lubricating fluid.
According to the present invention, this aim, these important objects,
and others which will better appear hereinafter are achieved with a weft thread
lubrication device having the specific features given in the appended claims.
Substantially, the device according to the invention is constituted
by a container for holding the lubricating fluid, in which a strip of spongy material,
such as felt or the like, is immersed; by capillary action, said strip becomes
impregnated with said fluid. This strip, having an adequate width, for example
between 100 and 150 millimeters, wraps around a nonrotating supporting roller
having a cylindrical sector which protrudes with respect to the surface of a lid
of the container, so that a respective portion of said strip, shaped like a cylindrical
sector and impregnated with lubricant, correspondingly protrudes with respect
to the surface of said lid and is exposed.
The weft thread to be lubricated is made to slide on the cylindrical-sector
portion, or exposed portion, of the strip of felt or the like; a guiding bush,
which can move transversely to the thread sliding direction with a reciprocating
motion imparted by a motorized screw, moves said thread in a cyclic manner from
one end to the other of said strip portion, so as to utilize its entire impregnated
surface. The supporting roller is subjected to manual angular movements imparted
by means of an external knob and having the purpose of replacing the exposed surface
of the felt strip when it shows signs of wear.
According to a further embodiment of the invention, which is aimed
at simplifying the device by avoiding its motorization, the cyclic motion for shifting
the thread from one end to the other of the exposed portion of the impregnated
strip is produced by the so-called "balloon" that the thread forms by unwinding
from the spool; in this case the guiding bush is eliminated and replaced with a
simple thread guiding slot.
The characteristics, purposes, and advantages of the device according
to the invention will become apparent from the following detailed description and
with reference to the accompanying drawings, given by way of non-limitative example,
- figure 1 is a perspective view of the lubrication device according to an embodiment
of the invention;
- figure 2 is a partially sectional side view of the device of figure 1;
- figure 3 is a perspective view, similar to figure 1, showing a different embodiment
of the device according to the invention.
With reference to figures 1 and 2, the lubrication device 10 comprises
a parallelepiped-shaped container 11, for holding the lubricating fluid 12, which
constists in a known manner of a vegetable low-viscosity oil or mixture of oils.
A strip 13 of felt, or other spongy material capable of absorbtion by capillary
action, is immersed in the mass of the lubricating fluid 12 and has a width of
for example 150 to 200 millimeters; one of its ends protrudes beyond a lid 14
of the container 11 to wrap partially around a support 15, which is shaped like
a cylindrical roller, is rigidly coupled to said lid, and can perform angular
movements, preferably in a stepwise manner, that are imparted manually by virtue
of a knob 16.
The roller 15 has a cylindrical portion protruding from an opening
of the lid 14 beyond the surface of said lid, so that a respective cylindrical
portion 13a of the strip 13, impregnated with lubricant, correspondingly protrudes
beyond said lid and is exposed. Two lips 17, preferably made of elastomeric material,
cover the gaps between the strip 13 and the lid 14 to prevent the entry of dust,
lint, and the like in the container 11. The thread F, that unwinds directly from
the spool, is made to slide, with a slight contact pressure, on the exposed portion
13a of the strip of felt 13. A bush 18, movable in a reciprocating manner, guides
the entry of the thread in the device and moves said thread in a cyclic manner
transversely to its sliding direction from one end to the other of the exposed
portion 13a of the felt strip 13, so as to utilize the entire impregnated surface
of said strip; a thread guiding slot 19 is arranged at the exit of the device.
For this purpose, the bush 18 is provided with a fixed female thread
in which a correspondingly threaded screw 20 engages; said screw is turned by a
reversible electric motor 21 controlled by limit switches (not shown) that are
sensitive for example to electrical input. The rotation of the supporting roller
15 allows to periodically change the exposed surface 13a of the felt strip when
it shows signs of wear.
The embodiment of figure 3, in which similar or corresponding parts
are designated by the same reference numeral, differs in that the bush 18, with
the corresponding kinematic system and actuation motor 20 and 21, are omitted
in favour of greater simplification. In this case, the cyclic transverse motion
of the thread is produced by the so-called thread "balloon", that is to say, by
the rotation which, when unwinding, said thread performs about the spool R, passing
in a cyclic manner in diametrically opposite points, such as A and B, and moving
from one side to the other of said spool.
A second thread guiding slot 22 is also provided at the inlet of
the device 10 in replacement of the bush 18, in order to control the transverse
movement of the thread and keep it in contact with the portion 13a of the strip
Without altering the concept of the invention, the details of execution
and the embodiments may of course vary extensively with respect to what has been
described and illustrated by way of non-limitative example without thereby abandoning
the scope of the invention that is defined by the appended claims.
Where technical features mentioned in any claim are followed by reference
signs, those reference signs have been included for the sole purpose of increasing
the intelligibility of the claims and accordingly such reference signs do not
have any limiting effect on the interpretation of each element identified by way
of example by such reference signs.