[0001] The present invention concerns an improved automatic needle loom of the kind where
the warp thread shed formation is controlled by a Jacquard system.
[0002] More particularly the present invention is directed to a needle loom for the manufacture
of narrow fabrics wherein the operating synchronism between weaving loom and jacquard
system is accomplished by means of separate motors.
[0003] Weaving looms are known in which the shed formation is controlled by a jacquard system.
In said looms the movement is driven by the weaving loom main shaft that, through
appropriated gear connections transmits the movement to Jacquard system allowing shed
formation with a required synchronism.
[0004] Connection between weaving loom driving shaft and corresponding jacquard elements
is quite complicated and it does not allow any independent programming of jacquard
operating speed within a single cycle. Also the cost of the devices necessary to assure
the appropriate operating synchronism is quite high.
[0005] Moreover the mechanical connection system between weaving loom and jacquard requires
a specific attention and care as well as a very qualified personnel to assemble and
disassemble the weaving loom/jacquard system. In addition being the weaving loom/jacquard
system very cumbersome on a vertical direction, it is not possible to transport it
in an assembled form.
[0006] On the other hand using mechanical means to connect jacquard to weaving loom results
in a high operating noisy that may reach levels unacceptable according to the present
law. It has to be taken in consideration that accepted noise values would be more
and more lower because of the authority attention to the noise pollution problem.
Furthermore it has also to consider that the use of mechanical means to connect weaving
loom to jacquard device would result in a rapid wear of the above mechanical mean
which requires frequent repairing to re-establish the weaving loom - jacquard movement
synchronism.
[0007] US - A - 5,613,526 discloses a system consisting of a series of independent motors
controlling shaft movement. Said motors may be of the kind of brushless motors.
[0008] The use of plurality of brushless motors implies quite high costs. Such a high expense
may be justified only by a very specific and expensive product manufacturing.
[0009] It is an object of the present invention a device for textile product manufacture
comprising a jacquard system for warp thread shed formation in which jacquard operation
is driven by a motor independent on the motor which drives the weaving loom movement.
[0010] It is a second object of the present invention a device for narrow fabric manufacture
allowing particularly low noise level, reduced repair necessity to re-establish the
synchronism between Jacquard and weaving looms, a simplified assembly which allows
the joint transportation of the constitutive elements (Jacquard and weaving loom)
without separating same and without requiring qualified personnel to reassemble the
system.
[0011] The above objects are met by the apparatus according to the present invention which
comprises a jacquard system for warp thread shed formation wherein the synchronism
between jacquard and weaving loom is assured by two separate motors, the motor controlling
jacquard movement being a direct current supplied synchronous motor, e.g. a brushless
motor.
[0012] Preferably the synchronism between the jacquard and weaving loom is assured by two
synchronous motors loom supplied by direct current of the kind of brushless motors
or equivalent which allows, in a easy way, the weaving loom shaft movement programming
as well as a very precisely definition of the rotation speed ratio of the driving
shafts.
[0013] The latter embodiment assures a good operation without any overheating, even in the
low running phase (about 60 rpm) of the weaving driving motor, therefore eliminates
the necessity of an auxiliary geared motor and reduces the overall cost and size of
the apparatus.
[0014] Moreover, as abovesaid, the use of direct current supplied synchronous motor as the
brushless motor or an equivalent one, enables, contrary to three-phase motors to prefix
the operating speed with a very high precision. In fact, the ratio of revolution number
of the weaving loom shaft and the revolution number of jacquard is generally two:
i.e. for each revolution of jacquard shaft, the weaving loom shaft makes two revolutions.
In conventional looms such a ratio is obtained by mechanical connection by using gear
wheels connected by means of belts or chains or it has been suggested to use two different
conventional motors (asynchronous, three-phase motors) driven on electrical axis and
controlled by appropriate inverters. Such embodiment has the inconvenient of a reduced
efficiency at low running and an imperfect synchronism.
[0015] Beside of assuring a perfect synchronism of the transmission ratio between jacquard
and weaving loom during all operating conditions (normal running, low running , acceleration
ramp, deceleration ramp, emergency stop), the use of two brushless motors or equivalent
ones, according to the present invention, allows to mantain said synchronism even
varying the speed within a single revolution, of the brushless motor shaft.
[0016] Therefore, even keeping unchanged the overall revolution ratio between revolution
number per time units of the jacquard driving shaft and the weaving loom driving shaft
it is possible to reduce the speed where necessary and then increase the speedy in
order to keep a constant ratio. This embodiment is only obtained with the use of a
brushless motor to drive the jacquard. This embodiment facilitates the jacquard system
operations during the phase in which the knives contact the hooks to select the hooks.
[0017] In fact by slowing down the impact speed between rising knives and hooks fastened
to magnets and reducing therefore hooks selection time a more safe operation is obtained
together with a reduction of mechanical stress of rotation elements that makes possible
an increase of the jacquard operating speed.
[0018] Even though the present invention is applicable to any weaving system using a jacquard
system for the warp thread shed formation, the device according to this invention
is advantageously applicable to needle weaving looms for the manufacture of narrow
ribbons, preferably the needle weaving looms for the label production.
[0019] Therefore the attached drawing cannot be interpreted as a limitation of the present
invention but only as illustrative thereof.
Fig 1 is a schematic view of a jacquard system applied to a needle weaving loom according
to the present invention for the manufacture of ribbon labels.
Fig 2 is a diagram showing the speed course of the jacquard and the needle weaving
loom motors asa function of the time.
Fig 3 is a schematic view of a mechanical system for the control of the jacquard upward
position in the assembling phase.
[0020] In the figures analogous elements have the same numerical reference.
[0021] In fig. 1, 1 is brushless motor shaft driving the drum rotation for the hook movement
and selection; 2 is the brushless motor driving the needle weaving loom, 3 is the
complex of the jacquard comprising elements; 4 is the warp beam supplying warp thread,
while 5 and 6 are smaller beam supplying the selvedge thread. 7 is the jacquard system
supporting plate as well as its brushless motor. Plated 7 can be lowered down as it
is illustrated in fig. 3 showing the jacquard-waving loom complex in a ready for shipping
phase. The lowered jacquard-waving loom complex can be shipped using standard size
containers. Fig. 2 is a diagram reporting on the axis of abscissa the angles relevant
to the rotation of the jacquard and weaving loom driving motor shafts. As ordinates
the shafts rotation speed in revolutions per minute is reported.
[0022] As it is evident from the figure, the jacquard driving motor shaft rotates at an
average speed that is one half of the speed of the weaving loom driving motor shaft.
However, while the rotation speed of the weaving loom driving motor shaft is always
constant, the rotation speed of the jacquard driving motor shaft change within each
single revolution angle. As a matter of fact, while the rotation speed of the weaving
loom driving motor shaft is shown as a straight line parallel to axis of abscissae
(A), the speed of jacquard driving motor shaft is shown as a sinusoidal line (C) since
said speed is higher in the ranges 0° to 90° and 180° to 270°, but is lower in the
in the ranges 90° to 180° and 270 to 360°. As it can be derived from fig. 2, the speed
ratio of two speeds: weaving loom and jacquard driving shafts is equal to two at beginning
and the end of each cycle, while during the cycle it oscillates around his value.
In fig. 2 it has been indicated with (B) the course of conventional jacquard system
wherein the Jacquard driving shaft rotates at constant speed.
1. A device for textile product manufacture comprising a jacquard system for warp thread
shed formation characterised in that the jacquard operation is driven by a synchronous
motor separated from the motor which drives the weaving loom movement and synchronised
with the same.
2. A device for textile product manufacture comprising a jacquard system according to
claim 1, characterised in that the movement synchronism between jacquard and weaving
loom is assured by two separate motors, the jacquard driving motor being a synchronous
direct current operated motor of the kind of brushless motor.
3. A device for textile product manufacture comprising a jacquard system for warp thread
shed formation according to one or more of preceding claims characterised in that
the synchronism of the jacquard system and weaving loom movements is assured by two
synchronous direct current operated motors of the kind of the brushless motors or
equivalent.
4. A device for textile product manufacture comprising a jacquard system for warp thread
shed formation according to one or more of preceding claims characterised in that
the overall ratio between the number of revolutions per time unit of the jacquard
driving motor shaft and weaving loom driving motor shaft is kept constant, but said
ratio is changed within each single cycle.
5. A device for textile product manufacture comprising a jacquard system for warp thread
shed formation according to claim 4 characterised in that the ratio between the speed
of the jacquard driving motor shaft and weaving loom driving motor shaft is changed
by reducing the jacquard driving motor shaft in the phase in which the knives are
in contact with hooks for the hook selection and by increasing such a speed in the
subsequent phases.
6. A device for textile product manufacture comprising a jacquard system for warp thread
shed formation according to one or more of preceding claims characterised in that
the jacquard system and its driving motor are placed on a plate that can be lowered
in order to reduce its size when the device has to be shipped.