FIELD OF THE INVENTION
[0001] The invention relates to a pile loom for driving a tension roller relative to a pile
warp associated with pile weaving and for setting a pile warp tension at an appropriate
value.
BACKGROUND OF THE INVENTION
[0002] Japanese Patent Publication No. 50-39177 (Sulzer) discloses a technique for passively
driving a tension roller in a pile loom. According to the technique of Sulzer, the
tension roller is supported to be freely swung while the tension roller is biased
by a spring and the like, and a warp is wound around the tension roller and the tension
roller is curved and deformed by a warp tension.
[0003] According to the technique of Sulzer, although the tension roller is structured to
be displaceable while undergoing a variation of tension (hereinafter referred to as
tension variation), the tension roller can not substantially follow a sharp tension
variation such as a shedding motion but operates while delayed from the time of tension
variation. During the weaving operation, the tension roller has to absorb all the
tension variation but there is a limit for the absorption of the tension variation.
Further, as the loom is turned at high speed, the influences caused by such a delay
from the time of tension variation becomes stronger so that the pile warp tension
is sharply increased or reduced, resulting in large tension variation. Such a large
and sharp tension variation can not be completely absorbed, arising a problem that
loom stoppage frequently occurs owing to missing plush loop and mispicking caused
by deflective shedding. In conclusion, according to the technique of Sulzer, the loom
has to be operated at a low revolution speed, resulting in the deterioration of productivity.
[0004] Meanwhile, the technique for positively driving a tension roller for pile warp (hereinafter
referred to as pile warp tension roller) generally comprises a support means for displaceably
supporting the pile warp tension roller, an electromotive actuator for biasing the
tension roller in a direction to apply tension via the supporting means, and a pile
warp tension controller for controlling the pile warp tension at a value lower than
a value at the time of steady operation in synchronization with the relative motion
between a reed and a woven cloth to move toward or away from each other for pile formation.
[0005] As a means for setting the pile warp tension at a value lower a value at the time
of steady operation, there are following two techniques. One technique is disclosed
in Japanese Patent No. 2,622,685 wherein a tension roller is stopped (position holding
state) from a biasing state in synchronization with the relative motion between a
reed and a woven cloth to move toward each other for pile formation, or the tension
roller is moved by a given amount in the direction to reduce the pile warp tension
in synchronization with the relative motion between the reed and the woven cloth to
move away from each other. The other technique is disclosed in Japanese Patent Laid-Open
Publication No. 2001-131845 wherein a biasing force from the electromotive actuator
is set at a value lower than a value at the time of steady operation in synchronization
with the relative motion between a reed and a woven cloth to move toward or away from
each other for pile formation.
[0006] Although the foregoing two techniques are improved somewhat compared with the technique
of Sulzer, these techniques are not complete because inertia of the tension roller
and that of the supporting members thereof act when the biasing force relative to
the tension roller is controlled, there occurs the delay of the motion (delay of displacement)
or excessive motion of the tension roller, resulting in the pile warp tension variation.
Furthermore, when the loom is turned at high revolution speed, such a delay of the
motion or excessive motion becomes large which appears as the sharp increasing or
reducing of the pile warp tension as it is, because the tension roller is formed of
a rigid body, arising problems that quality of a textile is deteriorated owing to
missing plush loop or , mispicking is induced by defective shedding of the pile warp
so as to stop the loom.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an object of the invention to provide a pile loom provided with
a pile warp tension controller capable of setting a pile warp tension at an appropriate
value even at a high speed operation of the pile loom.
[0008] To achieve the above object, a first aspect of the invention is a pile warp tension
controller for controlling a tension roller associated with a relative motion between
a reed and a woven cloth which is effected in accordance with a pile formation, and
it is structured such that the tension roller which is driven as set forth above is
deformable in the range of winding of a pile warp. The pile warp tension controller
of the invention is structured such that an electromotive actuator is torque driven
in response to a torque command value which is set in correspondence with an applied
tension or the electromotive actuator selectively undergoes torque control mode or
positional control mode. Further, a position command value is set at the pile warp
tension controller for executing positional control during a period when a relative
motion between the reed and the woven cloth for pile weaving and a torque command
value corresponding to the applied tension is set during a period other than the period
when the relative motion is performed. Since the pile warp tension controller is varied
in pile warp tension at the time of switchover between the relative motion, at the
time of driving of the electromotive actuator with a control mode corresponding to
respective commands, namely, owing to the driving manner of the tension roller, more
in detail, owing to the factor such as the relative motion between the reed and the
woven cloth or warp shedding motion which is performed for pile weaving, either the
driving for reducing such variation or the driving for rendering the pile warp tension
at a value suitable for the pile formation is included. In the latter driving, as
a more preferable example, at a period when the relative motion is performed and at
least at a prescribed period to include a beating time within a period when the relative
motion is performed for pile formation, the electromotive actuator is controlled for
applying tension at a period other than the predetermined period.
[0009] "The relative motion between the reed and the woven cloth" for pile formation includes
an operation for preparing a reed escape amount (appropriate distance between the
position of the cloth fell caused by the movement of a cloth and the original position
of the cloth fell, i.e. beating position of the cloth fell) by moving the reed and
the woven cloth away from each other and an operation for forming a pile by moving
the reed and the woven cloth toward each other. The pile formation process concretely
includes both cloth movable type pile loom (pile loom for displacing a cloth fell
position of the woven cloth back and forth while beating position is fixed), a reed
moving type (sword-beater type) pile loom (pile loom for displacing the beating position
back and forth while the cloth fell of the woven cloth is fixed).
[0010] As set forth in the prior art, in the weaving process, although a biasing force relative
to the tension roller is generally controlled for pile formation, there occurs the
increase or reduction of the pile warp tension owing to inertia of supporting members
of tension roller or inertia of tension roller per se, resulting in the delay of the
motion of the tension roller or excessive motion of the same.
[0011] On the other hand, according to the invention, since the tension roller has been
already in an elastic deformed state while undergoing a biasing force and the tension
roller per se is elastically deformed while undergoing the pile warp tension variation
so as to change warp path length, it is possible to control a sharp warp tension variation.
Accordingly, even if the loom is turned at high speed, a drawback which is caused
by the tension variation and has not been solved so far by the conventional technique,
namely, a drawback that the rate of operation is deteriorated owing to mispick caused
by missing plush loop or the defective shedding of the pile warp can be solved, and
hence it is possible to manufacture a high quality pile fabric with efficiency. The
arrangement for driving the tension roller for reducing the pile warp tension variation
caused by the relative motion between the reed and the woven cloth is not limited
to the structure set forth above, and it may be structured such that the electromotive
actuator is electrically, synchronously driven associated with the relative motion
between the reed and the woven cloth for pile weaving or it may be mechanically driven
via a driving mechanism coupled with the main shaft of the loom or swingably driving
the supporting means associated with the relative motion between the reed and the
woven cloth which is effected in correspondence with the pile weaving. The swingable
driving of the tension roller means that the tension roller is displaceably driven
back and forth relative to the warp in a direction to cancel the increase and reduction
of the warp tension caused by the relative motion between the reed and the woven cloth.
For example, even if there occurs an electric delay of the driving of the tension
roller or a mechanical swingable driving amount is roughly set at a value which is
deviated somewhat from an ideal value and there occurs the pile warp tension variation
owing to the relative motion set forth hereinbefore, the tension roller which has
been in an elastic deformed state while undergoing a biasing forth undergoes such
tension variation in the same manner as set forth above, so that the tension roller
is elastically deformed by it self to change the warp path length, thereby restraining
a sharp warp tension variation.
BRIEF DESCRIPTION OF DRAWINGS
[0012]
Fig. 1 is a side view showing a main portion of a pile loom;
Fig. 2 is an enlarged sectional view of a tension roller;
Fig. 3 is an enlarged sectional view of another tension roller;
Fig. 4 is a block diagram of a pile warp tension controller;
Fig. 5 is a block diagram of another pile warp tension controller;
Fig. 6 is a view showing a step of forming piles and an example of control thereof;
Fig. 7 is a timing chart showing an operation during one repeat cycle;
Fig. 8 is a block diagram of still another pile warp tension controller; and
Fig. 9 is a side view showing a main portion of another pile loom.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0013] Figs. 1 to 4 show an example where a tension roller is driven by an electromotive
actuator, and the electromotive actuator is biased with a torque which is lower than
a torque at the time of steady operation as to set a pile warp tension at a desired
low value during a period of relative motion between a reed and a woven cloth, at
least a given period including a beating time for forming piles, the tension roller
is extended in a direction of weaving width, and the tension roller is formed by a
spring member which is curved and formed in correspondence with a pile warp path.
[0014] First of all, Fig. 1 shows an entire cloth movable type pile loom 1 (hereinafter
referred as simply as pile loom) as an example. The pile loom 1 causes relative motion
between a reed 28 and a woven cloth 7 by moving a cloth fell 7a of the woven cloth
7 back and forth periodically for pile formation by a pile warp 2.
[0015] Many pile warps 2 are wound around an outer periphery of a let-off beam 3 in a sheet
shape in a weaving direction, and it is positively let off by the revolution of a
let-off motor 4, then it is wound around outer peripheries of a guide roll 5 and a
tension roller 6, and thereafter supplied to a direction of the cloth fell 7a. The
guide roll 5 is turnably supported at a fixed position relative to a loom frame 10.
[0016] The tension roller 6 is turnably supported back and forth by a tension lever 8 and
a fulcrum shaft 9 serving as a mechanical supporting system relative to the loom frame
10. The tension roller 6 is structured such that it is elastically deformed when receiving
a pile warp tension in the range of winding of the pile warp 2, described later, and
is supported not to turn relative to the tension lever 8. The tension lever 8 is turnably
supported by the fulcrum shaft 9 at a fixed position of the loom frame 10. The tension
lever 8 may be biased by a spring, not shown, in a direction to always apply a constant
tension relative to the pile warp 2, if need be.
[0017] The fulcrum shaft 9 is driven by an electromotive actuator 15 such as an AC servomotor
or a torque motor via gears 13a, 13b. The electromotive actuator 15 is controlled
by a pile warp tension controller 40, and is turned in either direction to generate
a turning force (torque) as a given force proportional to a current value.
[0018] In such a manner, the pile warp tension controller 40 converts an electric signal
serving as an output of the pile warp tension controller 40 into a turning force which
is proportional to the magnitude of the electric signal by controlling the electromotive
actuator 15, and further converts the turning force into displacement (movement) of
the gears 13a, 13b, the fulcrum shaft 9, the tension lever 8 and the tension roller
6, thereby causing the displacement to act upon the pile warp 2. As a result, a tension
of the pile warp 2 can be adjusted by the output of the pile warp tension controller
40 in a weaving process.
[0019] Meanwhile, the let-off motor 4 is controlled by a let-off controller 16. The let-off
controller 16 indirectly measures amount of consumption of the pile warps 2 as weaving
operation advances by sampling the displacement of the tension roller 6 or tension
lever 8 which is detected by a displacement detector 17 at a prescribed period, and
drives the let-off motor 4 in a let-off direction in correspondence with the thus
measured amount of consumption, and lets off the pile warp 2.
[0020] The let-off controller 16 adds number of revolutions corresponding to the displacement
of the tension roller 6 to a basic number of revolutions (revolution speed) of the
let-off motor 4 or subtracts number of revolutions corresponding to the displacement
of the tension roller 6 from the basic number of revolutions of the let-off motor
4, and drives the let-off motor 4 by the total number of revolutions so as to always
let off the pile warp 2 during weaving operation. Since the let-off controller 16
is a feed back control system and normally responds by a large time constant, and
hence it does not control a temporal displacement of the tension roller 6 back and
forth at the time of shedding motion or at the time of pile formation.
[0021] Meanwhile, a ground warp 18 is supplied by a ground warp let-off beam 19 as in the
past, and it is wound around a back roll 20, and guided forward to insert into heddles
21, and forms a shedding 22 together with the pile warp 2 by the vertical movement
of the heddles 21. The ground warp 18 crosses with a weft 23 at the position of the
shedding 22 and forms the woven cloth 7 of a pile textile together with the weft 23
which is beaten by the reed 28. The woven cloth 7 is wound around an outer periphery
of a take-up beam 27 after passing through a take-up roll 25 which is displaceable
back and forth, a take-up roll 26 at a fixed position, and a plurality of guide rolls
25a, 25b.
[0022] Owing to the movable type pile loom 1, the back roll 20 is also displaceably supported
back and forth by a ground warp tension lever 29 which is freely turnable relative
to a fulcrum shaft 30 in the same manner as the take-up roll 25, and it is biased
by a tension spring 31 in a direction to apply a given tension to the ground warp
18. Further, the fulcrum shaft 30 is supported by a fulcrum shaft 30b so as to swing
by a supporting arm 30a back and forth relative to the loom frame 10.
[0023] The take-up roll 25 is swingably supported by a lever 25c and a lever shaft 25d back
and forth, and is coupled with the supporting arm 30a by a link 25e, and it is moved
back and forth by a terry motion mechanism 24 such as a terry cam which is driven
by a main shaft 41 of the pile loom 1. In such a manner, both the back roll 20 and
the take-up roll 25 swing back and forth associated with the pile formation cycle,
and cause the woven cloth 7 and cloth fell 7a to move back and forth.
[0024] Although a beating position is always constant in the portable type pile loom 1,
both the woven cloth 7 and the cloth fell 7a are moved back and forth. Both the take-up
roll 25 relative to the woven cloth 7 and the back roll 20 relative to the ground
warp 18 are supported in a state to be displaceable back and forth as set forth above,
and when they move back and forth after a first pick beating in a state where they
are synchronous with the turning of the main shaft 41 by the terry motion mechanism
24, the cloth fell 7a is caused to move forward (cloth take up side) and an appropriate
reed escape amount is given by two times of loose picking. In the meantime, "first
pick" means beating the weft 23 until the weft 23 reaches the cloth fell 7a while
"loose picking" means beating until the weft 23 reaches merely up to a position corresponding
to the reed escape amount in front of the cloth fell 7a but not to beat completely
the weft 23 to reach the cloth fell 7a.
[0025] The pile warp 2 is let off while the let-off amount is increased or decreased in
response to the movement of the tension roller 6 during the let off operation at a
basic speed without direct relation with the back and forth motion of the back roll
20 and the take-up roll 25. On the other hand, although the turning of the ground
warp let-off beam 19, the take-up roll 26 and the take-up beam 27 is performed by
the driving of the electric motor or a mechanical let-off mechanism or a winding mechanism,
the arrangements thereof are the same as the prior technique, and hence the explanation
thereof is omitted.
[0026] When the pile loom 1 operates to progress the weaving, the pile warp 2 is woven in
the woven cloth 7, and hence the weaving sequentially advances forward so that the
tension of the pile warp 2 gradually increases. Since the tension roller 6 moves forwards
associated therewith, the tension lever 8 is turned clockwise in Fig. 1. The displacement
of tension roller 6 or the tension lever 8 at this time is always detected by the
displacement detector 17 as an electric signal which is proportional to the displacement
amount. Although the detection is always continuously performed, the detected electric
signal is utilized for the let-off control every prescribed sampling cycle by a sampling
technique, described later.
[0027] Since the signal detected by the displacement detector 17 becomes an input of the
let-off controller 16, the let-off controller 16 samples the detected signal at a
prescribed timing and finds an average value at a prescribed units of picking and
also calculates the command speed based on a deviation amount relative to a standard
value, so that when the let-off motor 4 is positively turned, the let-off beam 3 of
the pile warp 2 is turned in the let-off direction so as to let off the pile warp
2 to restrain the increase of the tension of the pile warp 2, thereby cancelling a
sharp tension variation of the pile warp 2 caused by the displacement of the tension
roller 6 or the tension lever 8.
[0028] The let-off motion of the ground warp 18 is let off by the electric motor type let-off
mechanism or mechanical let-off mechanism. Provided that the ground warp 18 is performed
by the electric motor type let-off mechanism, the controller thereof always continuously
lets off the ground warp 18 in response to the command speed corresponding to a basic
speed, detects the tension of the ground warp 18 during a let-off process, compares
the detected tension with a target tension, corrects the basic speed so that the tension
of the ground warp 18 is equal to the target tension value, and finally outputs the
corrected results as the command speed. Thus the let-off motion of the ground warp
18 is always continuously performed, and the let-off motion speed is varied in response
to the deviation relative to a target tension value.
[0029] Figs. 2 and 3 largely show the main portion of elastically deformable tension roller
6. First of all, the tension roller 6 shown in Fig. 2 is structured such that a sheet
metal cylindrical spring member 6b is eccentrically fixed to a bar 6a which extends
in a weaving width direction so as to envelope from the outside by a bolt 6c and a
holder 6d. The pile warp 2 is wound around a deformed circumferential surface of the
cylindrical spring member 6b and undergoes the increase of the tension so as to render
the spring member 6b flat. Since the spring member 6b is rendered elastically deformed
in flat, the tension of the pile warp 2 is reduced at the time of sharp variation.
The material, thickness, curvature (radius) of the cylindrical spring member 6b serving
as a typical constituent of the tension roller 6 are determined considering the tension
value or the variation range of the pile warp 2.
[0030] The tension roller 6 shown in Fig. 3 is structured such that one end of a sheet metal
C-shaped prismatic spring member 6b is eccentrically fixed to chamfered surface of
a bar 6a which extends in a weaving width direction so as to envelope from the outside
by a bolt 6c and a holder 6d. The pile warp 2 is wound around an elastically deformable
portion of the C-shaped prismatic spring member 6b and undergoes the increase of the
tension so that a free end of the spring member 6b is deformed. The tension of the
pile warp 2 is reduced by the elastic deformation of the spring member 6b at the time
of a sharp variation. The material, thickness, curvature (radius) of the spring member
6b serving as a typical constituent of the tension roller 6 are determined considering
the tension value or the variation range of the pile warp 2.
[0031] Fig. 4 shows an example of an internal construction of the pile warp tension controller
40. In this example, the pile warp tension controller 40 displaces the tension roller
6 into the tension application direction relative to the pile warp 2 in accordance
with the target torque while setting the target torques which is changed for every
period within one repeat period for forming a pile and driving the fulcrum shaft 9
of the tension lever 8 by the electromotive actuator 15 with the target torque for
every plural periods within one repeat period at the weaving time.
[0032] A driving control portion 42 shown in Fig. 4 receives plural, e.g., two commands
of target torques T1, T2 from a tension setting portion 43 and drives the electromotive
actuator 15 in a prescribed turning direction. The target torques T1, T2 correspond
to a target tension value which is applied to the pile warp 2 during a specific period
within one repeat and they are given by a setting device 44. A selection signal generator
45 receives a setting content given by a setting device 47 and a turning angle θ of
a main shaft 41 from an angle detector 46 which is coupled to the main shaft 41, and
outputs a selection signal for torque switching to the tension setting portion 43
at a prescribed timing in synchronization with a pile formation.
[0033] Fig. 5 shows control examples (1), (2), (3) relative to back and forth movements
of the woven cloth 7 and the cloth fell 7a within one repeat period (three picks),
the position of the tension roller 6, and turning intervals R1, R2, R3. In Fig. 5,
the control example [1] corresponds to the completion of the pile formation and the
state depicted by (2), (3), (4) correspond to a loose picking and a state depicted
by (5), (6) correspond to a first pick, and the pile formation is completed during
these states.
[0034] Fig. 7 shows the relation between the turning angle θ of the main shaft 41 within
one repeat period (three picks) shown on a lateral axis and a beating timing, weft
timing, shedding of the ground warp, shedding of a pile warp, movement of a woven
cloth, a selection signal, and a target torque shown on a vertical axis.
[0035] The driving control portion 42 shown in Fig. 4 sets the target torque T2 within the
turning intervals R1, R3 which are determined to include the relative motion between
the woven cloth 7 and the reed 28 based on the control example [1], namely, corresponding
to the low tension value of the pile warp 2 in a shedding state of the pile warp 2,
and also sets the target torque T1 corresponding to a normal tension value of the
pile warp 2 at the turning interval R2. It is needless to say that the target torque
T2 is smaller than the target torque T1.
[0036] In the first pick depicted by (5), (6), there does not occur missing plush loop by
such a setting of the tension so that a pile formation is ensured. It is needless
to say that the low tension value of the pile warp 2 can be appropriately changed
considering the shedding state of the pile warp 2 and the moving condition of the
woven cloth 7. Further, the selection period of the target torques T1, T2 is not limited
to those as illustrated, which can be changed, if need be. It is needless to say that
plural torques can be set even in the turning interval R2, if need be, and these torques
may be switched over therebetween.
[0037] With the pile loom 1 having such a construction, the pile warp tension is preferably
set at a high value to stabilize the operation of the pile loom 1 to prevent the mispicking
caused by the inferior warp shedding at the turning interval R2 so as to perform the
pile formation at a desired height and maintains at a low tension suitable for the
pile formation at the turning intervals R3, R1 so as to perform the pile formation
at a desired height. Accordingly, the pile warp tension controller 40 changes the
torque which biases the tension roller 6 for every period of the pile formation cycle,
and the tension roller 6 is structured to be displaced such that the applied torque
balances with the pile warp tension.
[0038] However, inertia of the tension roller 6 acts on the tension roller 6 so that there
occurs a delayed movement or excessive motion of the movement of the tension roller
6. If the tension roller 6 is formed of a rigid body as made conventionally, the tension
variation becomes prominent associated with such a delayed or excessive motion of
the movement of the tension roller 6 so that the missing plush loop or mispicking
occurs as described in the prior art. Whereupon, according to the pile loom of the
invention, the tension roller 6 is structured such that it is elastically deformed
while undergoing warp tension shown in Figs. 2 and 3 and it has been already deformed
somewhat by the biased or applied torque. Accordingly, when the tension roller 6 undergoes
tension variation, it is elastically deformed by itself so that the warp path length
is changed, resulting in the slackness of a sharp tension variation. This is described
more in detail next.
[0039] Before the beating for a pile formation, the relative motion between the reed 28
and woven cloth 7 to move toward each other is effected for effecting the pile formation,
wherein (1) when the tension roller 6 is delayed relative to the relative motion between
the reed 28 and woven cloth 7, the pile is hardly formed because the tension of the
pile warp 2 increases and there occurs missing plush loop. At this time, the tension
is prone to increase instantly but the tension roller 6 undergoes the increase of
the tension and is deformed so that the path length of the pile warp 2 is shortened
to restrain the increase of the tension. The tension lever 8 undergoes the increase
of reaction force from the tension roller 6 and moves in a direction to restrain the
increase of the tension, and also undergoes the decrease of reaction force by the
movement thereof so that the tension roller 6 returns the deformation to the original
state. Accordingly, the tension of the pile warp 2 during the period of relative motion
between the reed and woven cloth is maintained at a desired low value so as to reduce
the sharp increase of tension which has occurred so fat so that a pile is formed in
accordance with the reed escape amount at the beating time caused by the relative
motion between the reed 28 and the woven cloth woven cloth 7.
[0040] On the other hand, (2) when the tension roller 6 is rendered excessive relative to
the relative motion between the reed 28 and the woven cloth woven cloth 7, the tension
of the pile warp 2 lowers opposite to the previous case (1), so that it stops owing
to the mispicking caused by the defective shedding of the pile warp 2. Although the
tension of the pile warp 2 lowers instantaneously but the tension roller 6 which is
in the tension applied state has been already deformed, and hence it undergoes the
reduction of tension to recover to original state so that the warp path length is
deformed so as to extend, thereby restraining the reduction of tension. The support
member such as the tension lever 8 undergoes the decrease of reaction force from the
tension roller 6 and moves in a direction to restrain the reduction of tension, then
undergoes the increase of reaction force by the movement thereof so that the tension
roller 6 returns the deformation to the original state. Accordingly, the pile warp
tension is maintained at the desired low value during the period of relative motion
between the reed 28 and woven cloth 7 so that the sharp reduction of tension which
has occurred so far is reduced, ensuring the picking which is performed in parallel
with the relative motion.
[0041] After the beating for the pile formation, the relative motion between the woven cloth
7 and reed 28 is performed so as to move away from each other in order to prepare
the reed escape amount for the pile formation, wherein (3) when the tension roller
6 is delayed relative to the relative motion between the woven cloth 7 and the reed
28, the pile warp tension increases to pull out the pile warp 2 from the already formed
pile so that the pile height is reduced, resulting in the occurrence of missing plush
loop. In the same operation as the case (1), the increase of the pile warp tension
is reduced to prevent the pile warp 2 from being pulled out so that the occurrence
of missing plush loop can be prevented. (4) When the tension roller 6 operates earlier
than the relative motion between the woven cloth 7 and the reed 28, the tension reduces
so that the weft 23 is caught by the pile warp 2 which is in defective shedding so
that mispicking occurs and the pile loom 1 stops. As a result, in the same operation
as the case (2), reduction of the pile warp tension is reduced. Since the pile warp
tension is not reduced from the desired low tension during the period of time of relative
motion between the woven cloth 7 and the reed 28, the picking which is performed in
parallel with the relative motion is ensured.
[0042] Even if there occurs delayed or excessive motion of the tension roller 6 before or
after the beating for the pile formation, instantaneous increase of reduction of tension
is reduced to maintain a desired low tension so that a desired pile is formed and
a drawback that the operation of the pile loom 1 is damaged by the mispicking is solved.
As a result, a weaving can be performed even at a high revolution of the pile loom
1 which has not been realized so far, thereby improving a productivity and quality
of the woven cloth 7.
[0043] Fig. 6 shows an example of an internal construction of another pile warp tension
controller 40. In this example, the pile warp tension controller 40 has a speed command
portion 48 and a stop command portion 49 in addition to a tension setting portion
43, wherein the outputs of these constituents are selectively switched over therebetween
by a switching portion 50 to output the switched output to a driving control portion
42. A selection signal generator 45 receives a setting content given by a setting
device 47 and a turning angle θ of a main shaft 41 and outputs a selection signal
to the switching portion 50 so as to switch over the switching portion 50 at a prescribed
timing in synchronization with the pile formation.
[0044] During weaving, the pile warp tension controller 40 drives a electromotive actuator
15 while a torque control step, a speed control step, and a stop control step are
switched over therebetween in accordance with a period of time to include the relative
motion between a woven cloth 7 and a reed 28 within one repeat period of time for
the pile formation so that a force acting act upon a tension roller 6, a moving speed
of the tension roller 6 and a stopping position of the tension roller 6 are controlled.
[0045] The torque control is executed in response to a command value of a torque T which
is an output of the tension setting portion 43 so as to bias the tension roller 6
with a prescribed torque in a tension application direction at the time of sharp tension
variation of the pile warp 2. The speed control is executed in response to a command
of speed V which is an output of the speed command portion 48 by forcible movement
in the direction to reduce the tension of the pile warp 2. Further, a stop position
control is executed in response to a command of speed B from the stop command portion
49 so as to maintain the tension roller 6 in a stop state at a prescribed position.
The command of the speed B includes zero speed for stop operation.
[0046] The selection signal generator 45 executes the control example [2] upon receipt of
the turning angle θ of the main shaft 41 from the angle detector 46 and outputs either
the selection signal from the torque control, speed control, the stop control to the
switching portion 50 at a prescribed timing during the pile formation. A timing for
switching over between the torque control, the stop control, the speed control is
set by the setting device 47. Accordingly, the switching portion 50 selects a control
mode in response to the turning angle θ of the main shaft 41 and selectively outputs
the command value of torque T, a command of speed V and a command of speed B to the
driving control portion 42. The driving control portion 42 controls the driving of
the electromotive actuator 15 with a control mode corresponding to respective commands.
[0047] According to the control example [2] shown in Fig. 5, the electromotive actuator
15 undergoes speed control by speed V1 which is outputted corresponding to the amount
of movement during almost period of a turning interval R1 at the time of forward movement
of the woven cloth 7, namely, when the reed 28 and cloth fell 7a are moved away from
each other, so that the tension roller 6 is displaced while maintaining the pile warp
tension at the original low tension T2, subsequently, the electromotive actuator 15
undergoes stop control in response to the command of speed B at the end period of
the turning interval R1 so as to immediately stop the tension roller 6 so as to eliminate
the movement caused by inertia of the tension roller 6. Thereafter, the torque control
is executed in response to the command value of the torque T during a turning interval
R2 upon completion of the forward movement of the woven cloth 7 so as to maintain
the tension of the pile warp 2 at a target torque T1 which is set higher than the
low tension T2. Thereafter, the stop control is executed in response to the command
of the speed B to immediately stop the tension roller 6 during the period of turning
interval R3 so as to eliminate the movement caused by inertia of the tension roller
6, thereby rendering the tension of the pile warp 2 at the tension T2 to fit for the
pile formation which is lower than the target torque T1 by reducing the pile warp
tension while interlocking with the relative motion between the reed 28 and the woven
cloth 7 to move toward each other while the stop state is maintained. Thereafter,
the pile warp 2 is beaten toward the cloth fell 7a where the first picked weft 23
is moved backward, thereby forming a fresh pile. Then, the step is returned to the
initial step where the woven cloth 7 performs the forward movement so that the electromotive
actuator 15 undergoes speed control in response to the speed V1 which is outputted
corresponding to the amount of movement or momentum, and hence the pile warp tension
is maintained at the original low tension T2 as it is. That is, since the warp tension
fitted for pile formation is maintained even after the beating for pile formation,
the pile warp 2 can be pulled out from the newly formed pile, so that there does not
occur a drawback that the pile height lowers. Since the tension roller 6 is driven
so that the pile warp tension is varied corresponding to the pile formation cycle
in the same manner as the control example [1] shown in Fig. 5, and the tension roller
6 is structured to be elastically deformable, inertia of the tension roller 6 or inertia
of the supporting member such as the tension lever 8 for supporting the tension roller
6 acts on the driving of the tension roller 6 during a front or rear period of beating
for pile formation, resulting in the occurrence of delayed or excessive motion of
the tension roller 6. As a result, even if a sharp tension variation occurs, the tension
roller 6 undergoes such a tension variation and it is elastically deformed so as to
change the warp path length so that the tension variation is reduced.
[0048] According to the control example [3] shown in Fig. 5, the electromotive actuator
15 undergoes the stop control in response to the command of the speed B during the
turning interval R1, and undergoes torque control in response to the command value
of the torque T during the turning interval R2 so as to maintain the tension of the
pile warp 2 at the target value, thereafter undergoes the stop control in response
to the command of the speed B during the turning interval R3 so as to eliminate inertia
caused by the movement of the tension roller 6 so that the tension roller 6 is immediately
stopped and the tension of the pile warp 2 is maintained at a low value by the set
value.
[0049] The control examples [1] to [3] are formed to set the pile warp tension at values
fitted for pile formation and they are preferable for pile formation. However, according
to a pile fabric which is relatively easily woven, various command values can be set
so as to always apply the same applied tension to the pile warp 2 without limiting
to a beating period for pile formation and also without limiting to such control examples.
Further, it is possible to simplify the construction so as to position and drive the
tension roller 6 relative to the movement of the woven cloth 7. The driving means
of the tension roller 6 is exemplified hereinafter.
[0050] The first concrete example is an example to electrically and synchronously driving
an electromotive actuator 15 in correspondence with the relative motion between the
reed 28 and the woven cloth 7. Fig. 8 shows an example of an internal construction
of a pile warp tension controller 40 corresponding to the electrical and synchronous
driving of the electromotive actuator 15. This example is similar to the device shown
in Fig. 4 but the former is different from the latter in respect of the arrangement
of a speed command portion 56 instead of the tension setting portion 43 shown in Fig.
4.
[0051] The pile warp tension controller 40 includes a speed command portion 56 in addition
to a reference voltage supply 54 for setting the amount of movement 11 for moving
the tension roller 6 in correspondence with the amount of relative motion between
a reed 28 and a woven cloth 7, and outputs an output of the speed command portion
56 to a driving control portion 42. A selection signal generator 45 switches over
a command speed at a timing corresponding to the setting of the relative motion between
the reed 28 and the woven cloth 7 to move toward or away from each other upon reception
of a setting content which is given by a setting device 47 and a turning angle θ of
a main shaft 41, and outputs a selection signal to the speed command portion 56. More
in detail, a period when the woven cloth 7 is moved forwards and a period when the
woven cloth 7 is moved backwards are set in the setting device 47 as respective timings.
The selection signal generator 45 recognizes a first pick period or loose picking
period based on the turning angle θ, and outputs the selection signal which corresponds
to respective set periods to the speed command portion 56. Meanwhile, the amount of
movement 11 for moving the tension roller 6 is inputted to the speed command portion
56 via the reference voltage supply 54 and the speed command portion 56 can output
a positional command value corresponding to the amount of movement 11 and the moving
direction as a speed command value. The speed command portion 56 outputs a speed command
value V1 (V1 > 0) during the turning interval R1 where the woven cloth 7 is moved
forwards, for example, as illustrated in the control example [4] shown in Fig. 5,
and displaces the tension roller 6 in conformity with the movement of the woven cloth
7 while it outputs a speed command value V3 (V3 < 0) during the turning interval R3
where the woven cloth 7 is moved backwards to displace the tension roller 6 backwards,
and it outputs a speed command value V2 (V2 = 0) during the turning interval R2 where
the woven cloth 7 is not moved, to stop the tension roller 6. In such a manner, the
tension variation associated by the movement of the woven cloth 7 can be more reduced
compared with the device in which a conventional tension roller is passively driven
by moving and displacing the tension roller 6 in conformity with the amount of movement
of the woven cloth 7.
[0052] Although the electromotive actuator 15 is driven in synchronization with the turning
of the main shaft 41 in the foregoing examples, the tension roller 6 can be driven
by a swing motion mechanism having a driving source of the main shaft 41, namely,
by a driving mechanism. Fig. 9 shows an entire pile loom 1 provided with such a driving
mechanism which is different from the pile loom 1 in Fig. 1 in respect of the provision
of a driving mechanism 60 in place of driving mechanisms 13a, 13b, serving as members
for driving a fulcrum shaft 9, an electromotive actuator 15 and a pile warp tension
controller 40. The driving mechanism 60 is a mechanism for converting a turning movement
from the main shaft 41 into a swing motion corresponding to the movement of the woven
cloth 7 which is in turn acts on a fulcrum shaft 9 so as to produce motion like the
terry motion mechanism 24. The pile loom 1 can be more simplified by omitting the
driving mechanism 60 and the movement of a terry motion mechanism 24 is transmitted
to the fulcrum shaft 9 via some type of mechanical means to drive the fulcrum shaft
9.
[0053] Even if there occurs the pile warp tension variation by the occurrence of electric
delay caused by the driving of the tension roller 6 or by setting roughly the amount
of mechanical swingable driving which is somewhat deviated from an ideal value, or
by the relative motion between a reed 28 and the woven cloth 7, the tension roller
6 is provided to be elastically deformable as shown in Fig. 2 or Fig. 3 so that the
tension roller 6 which is in an elastically deformable state upon reception of a biased
force in the same manner as the previous embodiment, and it undergoes tension variation
and is elastically deformed by itself so that the warp path length is changed, thereby
restraining the warp tension variation.
[0054] The invention is not limited to the cloth moving type pile loom 1 but can be applied
to a sword-beater type (reed moving type) pile loom 1.
[0055] According to the first aspect of the invention, the pile warp tension controller
40 controls the driving of the electromotive actuator during a period when the relative
motion between the reed and the woven cloth is performed and the tension roller is
structured to be elastically deformable in the winding range of the pile warp.
[0056] Accordingly, the tension roller is driven in a tension swinging direction during
a period before beating for pile formation which is important to the pile formation
and during a period after beating for pile formation, and hence even if there occurs
a delayed or excessive motion of the tension roller with respect to the relative motion
between the reed and the woven cloth, resulting in the occurrence of a sharp pile
warp tension variation, the tension roller which is in an elastically deformable state
upon reception of the biased force undergoes such a tension variation and is elastically
deformable so as to change the warp pass length, thereby reducing the tension variation.
Accordingly, a desired low tension state is maintained so that the pile having a given
pile height can be formed reliably and inconvenience of damaging the operation of
the pile loom caused by mispicking can be solved. It is possible to perform weaving
even at high speed of revolution which has not been realized so far, thereby improving
productivity and quality of the woven cloth.
[0057] According to the second aspect of the invention, a torque command value corresponding
to an applied tension is set for every period and the electromotive actuator can be
torque driven while selecting an appropriate command value so that the tension control
of the pile warp can be ideally performed.
[0058] According to the third aspect of the invention, since the pile warp tension controller
is structured to select either the torque control mode or positional control mode
so that an appropriate control mode is performed reliably by selecting either control
mode, ensuring the pile formation.
[0059] According to the forth and fifth aspects of the invention, the electromotive actuator
is driven at a tension which is suitable for pile formation at a value lower than
the normal pile warp tension during a period including a period before or after the
beating for pile formation which is a period important for the pile formation, the
pile formation is more ensured.
[0060] According to the sixth and seventh aspects of the invention, the arrangement for
driving the tension roller is more simplified, and even if there occurs a delayed
or excessive motion of the tension roller or a mechanical swingable driving amount
is roughly set at a value which is deviated somewhat from an ideal value and there
occurs the pile warp tension variation owing to the relative motion set forth hereinbefore,
the tension roller undergoes such a tension variation and is elastically deformed
by itself to change the warp pass length, thereby restraining sharp warp tension variation.
[0061] According to the eighth aspect of the invention, since the tension roller is structured
by a leaf spring member which extends in a direction of width of weaving and is curved
in correspondence with the warp path, the warp tension variation in the direction
of width of weaving is prevented by the elastic deformation of the leaf spring member,
thereby correcting a locally minute tension variation.