On loom weft texturizing

Filament threads such as rayon threads which may be smooth or partly texturized for protection, are texturized or entangled in the loom just prior to their insertion into a loom shed as weft threads. For this purpose a texturizer (4) is positioned between a filament thread supply spool (1) and a weft thread accumulator (3). The accumulator in turn is positioned just upstream of an air insertion nozzle (11) for injecting the weft threads into a loom shed. The texturizing is sufficient to lock the filaments into the filament thread body so that these texturized filaments form threads that can be pneumatically transported through the loom shed without causing so-called blow-outs of individual filaments out of the weft thread body.

PRIORITY CLAIM 
This application is based on and claims the priority under 35 U.S.C. 
.sctn.119 of German Patent Application 196 53 028.8, filed on Dec. 19, 
1996. The entire disclosure of German Patent Application 196 53 028.8 is 
incorporated herein by reference. 
FIELD OF THE INVENTION 
The invention relates to the treatment of smooth or partly textured 
filament thread for use as weft threads in a pneumatic loom. The treatment 
in the form of entangling takes place between a filament thread supply 
spool and a weft accumulator roller while the loom is operating. 
BACKGROUND INFORMATION 
The use of smooth or partly textured weft yarns, particularly synthetic 
filament weft yarns in looms with a pneumatic weft insertion has posed a 
problem because these relatively smooth filament threads have a tendency 
to cause faulty weft insertions into a loom shed, especially into a 
pneumatic weaving loom in which the weft threads are transported through a 
weft insertion channel extending through the loom shed, by a main 
insertion nozzle and a plurality of relay nozzles. This problem is 
relatively small or nonexistent where such smooth or partially textured 
weft threads are used in a gripper loom or in a projectile weaving loom in 
which the transfer of the weft thread takes place mechanically. Thus, in 
such a mechanical transfer it is irrelevant whether the filament threads 
are completely partly or not at all texturized. However, it appears that a 
texturized thread is even preferred in gripper looms compared to smooth 
filament threads. 
In connection with the use of synthetic filament weft yarns as weft threads 
in pneumatic looms, the degree of texturizing of the initially smooth 
yarns is of substantial importance because the thread surface 
characteristers determines the probability of faulty weft insertions. It 
is generally known that synthetic filament weft threads available on the 
market must be treated in a certain texturizing or entangling operation 
prior to using these threads in a pneumatic weft insertion loom in order 
to prevent individual filaments from popping out of the thread. However, 
conventional thread texturizing operations outside a loom achieve a weft 
thread texture that does not take into account the conditions that must be 
met for using such filament yarns in a pneumatic weft insertion loom. 
Practical experience has shown that conventional texturizing outside the 
loom results in yarns which do not meet ideal air insertion requirements 
because the texturizing does not take into account the conditions that 
must be satisfied when these yarns are to be used as weft threads in 
pneumatic weft insertion looms. For example, conventionally texturized 
weft threads are not contemuously texturizing along the entire thread 
length. Actually, conventionally texturized filament threads have only 
texturized points which are relatively widely spaced from one another 
along the length of the filament weft thread. The purpose of such 
texturized points is primarily to avoid an untwisting of the filaments in 
a filament thread such texturized points do not prevent individual 
filaments from becoming loose between texturized points. 
Such conventionally texturized weft threads with widely spaced texturized 
points are only marginally or not at all suitable for use as weft threads 
in a pneumatic weft insertion loom because the formation of so-called 
blown-out weft threads that mar the fabric appearance and frequently 
require the removal of a blown-out thread cannot be avoided. By a 
blown-out thread is meant a weft thread that, due to the pneumatic 
insertion into the shed, has been untwisted at least partly by the weft 
insertion jets, whereby individual filaments pop out of the body of the 
filament thread. This blow-out takes place primarily when the main 
insertion jet or any of the relay jets impacts on the weft thread along a 
section outside a texturized point. Such thread sections can be relatively 
long between two texturized points in the same conventional filament weft 
thread. The term "texturizing" as used herein includes initial texturizing 
where the weft thread is smooth and further or post-texturizing where the 
weft thread is already provided with an initial texturizing. 
OBJECTS OF THE INVENTION 
In view of the above it is the aim of the invention to achieve the 
following objects singly or in combination: 
to make smooth or partly textured filament threads ready for use as weft 
threads in a weaving loom by exposing these filament threads to a 
texturizing or at least to a post-texturizing treatment directly in a loom 
prior to the accumulation of these threads on a weft thread accumulator 
roller in the loom; 
to perform the texturizing or post-texturizing treatment operation in 
response to the operational conditions of the weft thread accumulator; and 
to avoid in connection with the use of filament threads as weft threads in 
a pneumatic loom a so-called over-blowing or blow-out of filaments while 
simultaneously avoiding an excess application of a texturizing or 
post-texturizing treatment. 
SUMMARY OF THE INVENTION 
The above objects have been achieved according to the invention by applying 
a texturizing operation or treatment smooth or partially texturized 
filament threads when these threads travel from a filament thread supply 
spool to a weft thread accumulator roller, in a loom whereby the 
application of the texturizing treatment is so controlled that the 
filament threads become useable as weft threads in an air weaving loom. 
Preferably, the control is performed by feedback control signals 
signifying the withdrawal speed of the filament yarns from the filament 
supply spool. By sensing the withdrawal speed the respective signal 
signifies. According to the invention the present apparatus comprises a 
texturizing device positioned between a filament thread supply spool and a 
weft thread accumulator. The texturizing device or simply the texturizer 
applies a pneumatic pressure controlled fluid stream to the filament 
thread to bind the filaments into the thread body. For this purpose the 
texturizer is connected through a controllable pressure control valve to a 
source of fluid under pressure and the controllable valve is connected to 
a central loom control for controlling the valve and thus the fluid 
pressure in the texturizer in response to control values stored as a 
program in a memory of the loom control and/or in response to feedback 
control signals or values received from a sensor that monitors the current 
operational state of the weft thread accumulator. Both the texturizer and 
the weft accumulator are controllable by the loom control either in open 
loop fashion in response to a control program stored in a memory of the 
loom control and/or in closed loop fashion in response to sensed signal 
values representing the operational state of the weft accumulator that it 
operates or that it has stopped. 
In a preferred embodiment the control of the texturizing or 
post-texturizing treatment depends on the withdrawal speed of the weft 
thread, whereby the texturizing is applied on a continuous basis, 
preferably a continuous but variable basis. More specifically, the 
continuous texturizing takes place only as long as the respective weft 
accumulator is operating and the texturizing is switched off when the 
respective accumulator stops. In connection with the use of a plurality of 
different weft threads for example different color and/or pretexturized 
weft threads, one or the other weft thread supply is temporarily switched 
off, the respective texturizer is also switched off in response to a 
signal signifying the respective off-state of the corresponding weft 
accumulator. To that extent, the texturizing is discontinuous. 
According to the entire invention an adequate and uniform texturizing is 
applied along the length of a filament yarn, whereby the adequacy is 
determined by the requirement that the pneumatic weft insertion must not 
result in the above mentioned so-called over-blowing of the weft threads. 
This adequacy is assured if the jets that transport the weft thread 
through the weft insertion channel including the relay jets, impinge on a 
weft thread length that has been provided on its way to the weft 
accumulator with the required texture or entangling, whereby impinging on 
weft thread portions in which the filaments are not adequately locked into 
the thread is avoided.

DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS AND OF THE BEST MODE 
OF THE INVENTION 
FIG. 1 shows a filament thread supply spool 1 for supplying filament thread 
2 to a thread guide 4A which leads the filament thread 2 into a nozzle 
forming a texturizer 4. The texturizer 4 texturizes the filament thread 2 
with a pressurized fluid flow to present a weft thread 2A at the exit of 
the texturizer 4. The sorted thread 2A is suitable for weft insertion in a 
pneumatic loom. For this purpose the filaments must be locked into the 
body of the filament thread so that individual filaments cannot stick out 
of the thread body. The texturized weft thread 2A is pulled onto a thread 
storage drum in a weft thread accumulator 3 provided with at least one 
sensor S. The weft thread accumulator 3 delivers the weft thread 2A to a 
main injection nozzle 11 which receives its fluid under pressure P from a 
pressure source 10 forming part of the loom. The nozzle 11 injects the 
weft thread into the loom shed formed by the warp threads and the 
auxiliary nozzles AN transport the weft thread through the weft insertion 
channel in the loom shed. 
The weft accumulator 3, more specifically the drive motor of the 
accumulator, is electrically controllable through an electrical control 
conductor 5 connecting the motor of the accumulator 3 to the central loom 
control 6. The central loom control 6 has a memory M in which an operation 
program for the accumulator 3 and for the texturizer 4 are stored. 
Additionally, the central control 6 processes signal values received from 
the sensor S through a conductor 12. These signal values represent for 
example the operational state of the weft thread accumulator 3, the r.p.m. 
of the accumulator motor, and thus indirectly the withdrawal speed of the 
filament thread 2 from the spool 1, and similar values. A first control 
output conductor 8 of the control 6 is connected to a proportional closed 
loop pressure control valve 7 that includes a proportional valve member 7A 
and a pressure regulator 7B responsive in a closed loop fashion to a 
control signal from the control 6 through the control conductor 8. The 
valve member 7A is connected through a pressurized fluid line 9 to the 
pressure source 10 and to the inlet 4B of the texturizer 4. The pressure 
source 10 provides, for example a fluid under a pressure P1 while at the 
exit of the valve 7A the pressure is at a different pressure value P2 
suitable for the tangling operation. The selection of the particular 
pressure will depend on the type of filament thread to be treated in the 
texturizer 4 for texturizing. 
FIG. 2 shows the texturizer 4 in section. The texturizer 4 has a 
longitudinal bore 4C communicating with the inlet 4B so that a fluid flow 
F through the pressure line 9 enters into the bore 4C. The fluid flow F 
impinges on the bore wall opposite the inlet 4B in the bore 4C, whereby 
the flow is divided into two flow portions FA and FB exiting at opposite 
ends of the bore 4C. Each of the flow portions FA and FB may assume a 
spiral flow configuration during the travel from the center of the bore 4C 
to the exits thereof for texturizing and thereby locking the individual 
filaments into the body of the filament thread weft thread 2A. 
In operation, a viscous filament yarn 2 for example of the weight 
characteristic 330 dtex (decigrams per one thousand meters) is stored on 
the coil or spool 1. It is assumed that this filament thread 2 does not 
have any texturizing yet. However, normally these viscous yarns have a 
so-called protection twist of about 70 to 90 turns per meter which may be 
referred to as pretexturizing. However, such protection twist does 
normally not provide the required closure or locking of the individual 
filaments into the thread necessary for pneumatic weft insertion. Thus, a 
so-called blow-out of a filament during a weft insertion by the main 
insertion nozzle 11 cannot be prevented. To avoid a blow-out, further or 
post-texturizing according to the invention is required to provide the 
texture for the weft threads required for faultless pneumatic weft 
insertion. 
In operation the weft thread accumulator 3 is started by a signal from the 
control 6 through the control conductor 5 to cause the accumulator drum 3A 
to rotate. As a result, the filament yarn 2 is withdrawn from the spool 1 
with a defined withdrawal speed that depends on the rotational speed of 
the drum 3A. Simultaneously with the starting of the accumulator 3, the 
closed loop control valve 7 is opened for providing the required fluid 
flow under pressure P2 into the inlet 4B in response to a control signal 
on the control conductor 8 from the control 6. 
The pressure regulator 7B which conventionally is an integral part of the 
valve 7 makes sure that the pressure P2 supplied into the texturizer 4 is 
adjusted in response to the travel speed of the filament thread 2 through 
the texturizer 4 which in turn depends on the r.p.m. of the accumulator 
drum 3A in the accumulator 3. The pressure P2 may be smaller or larger 
than the pressure P1. The arrangement is such, that when a high withdrawal 
speed is applied to the filament thread 2, the pressure P2 at the inlet 4B 
of the texturizer 4 is automatically adjusted in closed loop fashion. If 
the loom operates in a so-called mixed weft insertion, namely the filament 
threads are supplied by two or more accumulators 3 in an alternating 
fashion, the fluid supply to the respective texturizer 4 will be stopped 
when the corresponding accumulator 3 is stopped either in accordance with 
a program stored in the memory M of the central loom control 6 or in 
response to a signal from the sensor S. Stated differently, the supply 
pressure P2 is also reduced to zero when the accumulator 3 stops. This 
feature has the advantage that the filament threads will not be over 
texturized. With the help of the sensor S the valve 7 can be controlled 
independently of any program to stop the supply of fluid under pressure in 
response to a signal signifying that the accumulator 3 has stopped for 
whatever reason. Such a signal will be supplied through the conductor 12 
from the sensor S through the central control 6 to the valve 7 for a 
closed loop control of the texturizing in response to the weft thread 
withdrawal speed. 
The texturizing will be considered to be sufficient as far as sections of 
threads are separated by smooth sections of threads if the auxiliary jets 
from the relay nozzles AN always encounter a texturized or post texturized 
portion of the filament weft threads. The invention is useful in 
connection with fully smooth filament threads and with filament threads 
having so-called protection twists at spaced intervals along the filament 
thread. The treatment providing such twists may be referred to as 
pre-texturizing. 
Although the invention has been described with reference to specific 
example embodiments, it will be appreciated that it is intended to cover 
all modifications and equivalents within the scope of the appended claims. 
It should also be understood that the present disclosure includes all 
possible combinations of any individual features recited in any of the 
appended claims.