[0001] The present invention refers to a device for enlarging and straightening the structure
of a fabric.
[0002] The prior art shows devices that take care of enlarging a fabric and removing small
longitudinal pleats by using cylinders with staves. These cylinders are equipped on
their external surface with a plurality of staves arranged longitudinally to the rotation
axis of the cylinder itself and able to slide according to an alternative movement
controlled by two flanges arranged diagonally to the cylinder ends and aimed to guide
the alternate and symmetric movement of the staves themselves.
[0003] In order to straighten the weft of a fabric, the prior art provides for more or less
efficient devices. As an example, it is useful to mention here machines equipped with
at least two idle wheels with pins keyed onto a transmission shaft, through which
a transverse tension with respect to the weft direction is applied to the fabric,
due to the relative speed change that can be generated between the two wheels.
[0004] From what is stated above, it is clear that, in the textile field, in case both a
straightening and an enlargement of a fabric must be carried out, there occurs the
problem of having to always arrange in series a straightening device and an enlarging
device, with obvious problems of costs and space.
[0005] In another situation, there could be a need of having to enlarge a fabric that is
only affected by a slight weft distortion, whose correction would not justify the
use, and above all the cost, of a straightening device
ad hoc, thereby having to do without the necessary corrective interventions.
[0006] Another problem that very often occurs depends on the fact that often the various
fabric working machines are relatively spaced away one from another; due to such distances
that the fabric must travel in order to access the various phases of its working cycle,
the fabric weft, though already subjected to a straightening and/or enlarging treatment
by means of the known machines, tends to assume again distortions, making thereby
the previous corrective workings partially useless.
[0007] Object of the present invention is solving the above prior-art problems by providing
a device that allows simultaneously performing both functions of enlarging and straightening
a textile structure in order to enlarge the fabric and correct possible weft distortions
of the fabric weft itself.
[0008] Another object of the present invention is providing a device that can be easily
arranged next to any textile machine in order to supply such machine with a fabric
whose distortions have been corrected a few seconds before, without thereby giving
them time to be formed again.
[0009] The above and other objects and advantages of the invention, as will appear from
the following description, are obtained by a device for enlarging and straightening
a textile structure as claimed in Claim 1. Preferred embodiments and non-trivial variations
of the present invention are claimed in the dependent Claims.
[0010] The present invention will be better described by some preferred embodiments thereof,
given as a non-limiting example, with reference to the enclosed drawings, in which:
- Figure 1 shows a side view of an embodiment of the enlarging and straightening device
according to the present invention;
- Figure 2 shows a top view of an embodiment of the enlarging and straightening device
according to the present invention;
- Figure 3 shows a sectional view along the dashed line A-A shown in Fig. 1 of an embodiment
of the enlarging and straightening device according to the present invention; and
- Figure 4 shows a sectional view along the dashed line B-B shown in Fig. 3 of an embodiment
of the enlarging and straightening device according to the present invention.
[0011] With reference to the Figures, it can be noted that the device 1 according to the
present invention is composed of a carrier axle 10 on which a first roller 2 and a
second roller 3 are keyed-in side by side, each roller 2, 3 being equipped on its
external surface with a plurality of staves 4, 6 that are sliding along the direction
parallel to the longitudinal axis of the rollers themselves, and with a plurality
of fixed staves 5, 7. The rollers 2, 3 are keyed-in onto the carrier axle 10 so that
the respective fixed staves 5 and 7 are side by side, while the sliding staves 4 and
6 can, during their movement, be partially extended outside the surface of their own
roller 2, 3. Each sliding stave 4 slides along the same direction of its own homologous
stave 6 but along the opposite sense; such alternate symmetric sliding movement of
the staves 4 and 6 is caused by two lateral rotating flanges 8, 9 that are symmetrically
slanted with respect to the rotation axis of the carrier axle 10, arranged at the
two end sides of the rollers 2, 3 and to which the sliding staves 4 and 6 are respectively
connected, at one of their ends. Each roller 2, 3 further cooperates with the carrier
axle 10, by interposing at least one free wheel 11, 12 for each roller 2, 3.
[0012] During the operation of the device 1, the fabric 13 is inserted onto the rollers
2, 3 that are rotated by the sliding movement of the fabric 13 itself, imposed by
the working process. During the rotation of rollers 2, 3, the connection of the sliding
staves 4 and 6 to their respective slanted flanges 8, 9 generates an alternate symmetric
sliding movement of the staves 4, 6 themselves that generates an enlarging effect
of the fabric 13.
[0013] The free wheels 11 and 12 allow the two rollers 2, 3 to rotate independently one
from the other but along a single direction. In this way a relative speed can be created
between the two rollers 2, 3 that generates a transverse tension to the weft, creating
a straightening effect for the threads of the weft itself. The straightening effect
efficiency according to the present invention can be increased by placing upstream
(or downstream) of the device 1 a known adjusting cylinder 14; such adjusting cylinder
14 is a rotating roller that is free of assuming different slants and is able to supply
the fabric 13 to the device 1 removing possible excessive tensions on the fabric caused
by the straightening effect itself. This adjusting cylinder 14 is hinged with two
degrees of freedom and, in another possible application, can be adapted to also perform
the function of a dancer cylinder, thereby saving parts and costs when manufacturing
the device of the invention.
[0014] The device 1 according to the present invention, in another preferred embodiment,
can be coupled with a motor 15, for example an electric motor, aimed to rotate the
carrier axle 10; in this way it is possible to control the longitudinal tension of
the fabric 13 without impairing, due to the presence of the free wheels 11, 12, the
freedom of independent movement of the rollers 2, 3.
[0015] The device 1, due to its reduced encumbrances and to the different functions that
distinguish it, can be easily arranged upstream, downstream or integrated with any
other textile machine in order to be able to always guarantee, in any working phase,
an efficient straightening of the fabric and the absence of pleats and weft distortions.
1. Device (1) for enlarging and straightening a fabric (13),
characterised in that it further comprises:
- a first roller (2) equipped on an external surface thereof with a plurality of sliding
staves (4) adapted to slide along a direction that is parallel to a longitudinal rotation
axis of said roller (2), and with a plurality of fixed staves (5);
- a second roller (3) equipped on an external surface thereof with a plurality of
sliding staves (6) adapted to slide along a direction that is parallel to a longitudinal
rotation axis of said roller (3), and with a plurality of fixed staves (7);
- at least two free wheels (11, 12);
- a carrier axle (10), said first roller (2) cooperating with said carrier axle (10)
by interposing at least one of said free wheels (11, 12), said second roller (3) cooperating
with said carrier axle (10) by interposing at least one of said free wheels (11, 12),
said free wheels (11, 12) being adapted to allow a relative rotation speed between
said first roller (2) and said second roller (3);
- two lateral rotating flanges (8, 9), said flanges (8, 9) being symmetrically slanted
with respect to a rotation axis of said carrier axle (10), each one of said flanges
(8, 9) being respectively arranged on one external side of said first roller (2) and
of said second roller (3), each one of said sliding staves (4) being connected at
one of its ends to said flange (8) and each one of said sliding staves (6) being connected
at one of its end to said flange (9), said flanges (8, 9) being further adapted to
realise an alternate symmetric sliding movement of said sliding staves (4, 6).
2. Device (1) for enlarging and straightening a fabric (13) according to claim 1, characterised in that it comprises a motor (15) connected to said carrier axle (10) adapted to drive the
rotation of said carrier axle (10).
3. Device (1) for enlarging and straightening a fabric (13) according to claim 1 or 2,
characterised in that it comprises, upstream of said device (1), at least one adjusting cylinder (14),
said adjusting cylinder (14) being a rotating roller that is free of assuming different
slants and is able to supply the fabric (13) to said device (1) removing possible
tensile differences on said fabric.
4. Device (1) for enlarging and straightening a fabric (13) according to claim 1 or 2,
characterised in that it comprises, upstream of said device (1), at least one adjusting cylinder (14),
said adjusting cylinder (14) being a rotating roller that is free of assuming different
slants and is able to supply the fabric (13) to said device (1) removing possible
excessive weft tensile differences on said fabric, said adjusting cylinder (14) being
further hinged so that it is adapted to operate as dancer cylinder.