-
This invention relates to a method for controlling
restart of weaving operation of a loom that enables to
effectively prevent formation of a filling bar in a fabric in
restarting weaving operation of the loom.
-
When a loom such as a jet loom is brought to a
suspended state due to weft insertion failure or electric
power outage, for example, the loom is driven in a backward
direction to conduct a pick finding, and an improperly
inserted weft yarn or a weft yarn having a possibility of
insertion failure is completely removed. Then, the loom is
brought to a specific start state, and the weaving operation
is restarted.
-
When the weaving operation of the loom is restarted,
there is a disadvantage that the density of the weft yarn may
be varied in the vicinity of the cloth fell, and a filling
bar may be formed in the fabric. In order to prevent such a
drawback, there is proposed an arrangement in which the loom
is restarted while giving vibration to the warp yarn by way
of an eccentric roller (see Japanese Unexamined Patent
Publication No. 8-246296).
-
In the above conventional art, since vibration given to
the warp yarn by way of an eccentric roller is not
sufficiently large, the effect of preventing formation of a
filling bar is insufficient. Specifically, a fabric cannot
have a desired specific weft yarn density by beating only
once, but several times of beating are required to obtain a
desired proper weft yarn density. Therefore, the weft yarn
density varies from rough to tight in the vicinity of the
cloth fell as distanced from the cloth fell. When the loom is
restarted after a temporary stop, and weft yarn insertion is
resumed while giving vibration to the warp yarn, movement of
the weft yarn by beating in the fabric is not the same as in
the normal weaving operation before the temporary stop
because a strain of the warp yarn in the weaving operation
after the temporary stop is not the same as that in the
normal weaving operation before the temporary stop. As a
result, the warp yarn density is not kept constant.
-
It is an object of this invention to provide a method
for controlling restart of weaving operation of a loom which
has overcome the problems residing in the prior art.
-
It is another object of this invention to provide a
method for controlling restart of weaving operation of a loom
that enables to effectively prevent formation of a cloth fell
resulting from varied weft yarn density without rotating a
main shaft, namely by restarting weaving operation of the
loom by moving a heddle frame or frames up and down in a
state that all the devices other than the heddle frames are
kept in an inoperative state.
-
According to an aspect of this invention, a loom is
restarted by moving at least one heddle frame up and down
without a pause while keeping a main shaft non-rotated after
confirming that the main shaft is set to a restart position,
and by rendering all the heddle frames to a synchronous
relation to the main shaft. The "synchronous relation" in
this specification means that each heddle frame is brought to
a certain phase relative to the main shaft so that each
heddle frame is operated in accordance with a shedding
pattern in a normal weaving operation.
-
According to another aspect of this invention, the
heddle frame is selectively moved up and down in accordance
with a heddle frame moving pattern dedicatedly used for the
heddle frame or with a shedding pattern in the normal weaving
operation.
-
According to yet another aspect of this invention,
after the heddle frame is moved up and down, the heddle frame
is rendered to a synchronous relation to the main shaft.
-
According to still another aspect of this invention,
the heddle frame is moved up and down by a certain number of
times, wherein the number is an integer.
-
In the inventive method, the loom is so designed that
the heddle frames are moved up and down without a pause while
keeping the main shaft non-rotated after confirming that the
main shaft is set to the restart position to generate a
sufficient strain in the warp yarn. Subsequently, the weaving
operation of the loom is restarted after all the heddle
frames are rendered to a synchronous relation to the main
shaft. Specifically, in this arrangement, constant weft yarn
density can be secured by properly moving the weft yarn in
the fabric by beating operation after the loom is restarted.
Thereby, a filling bar in the fabric is prevented. Since the
heddle frames are moved up and down without rotating the main
shaft, the heddle frames are driven by a dedicated driving
motor other than a main motor for driving the main shaft, and
the number of times and the speed of moving the heddle frames
up and down are properly set depending on, for example, the
kind of warp yarn and weft yarn.
-
The number of times of moving the heddle frame up and
down may range from several to several tens of times in terms
of a reciprocating motion, and the speed of moving the heddle
frame up and down may be the same as the speed in a normal
weaving operation, or may be slower or faster than the speed
in the normal weaving operation. Specifically, the speed of
moving the heddle frame up and down is preferably set in the
range from about 50 to 200 % relative to that in the normal
weaving operation for the following reasons. If the speed of
the heddle frame is less than 50%, separation of the warp
yarn is deteriorated with the result that a desired warp yarn
strain is not provided. On the other hand, if the speed of
the heddle frame is above 200%, an excessive stress is likely
to be exerted to a driving system for driving the heddle
frames.
-
Moving the heddle frames up and down in accordance with
the dedicated vertical movement pattern makes it possible to
move the heddle frames up and down without a pause
irrespective of a required weaving pattern. Thus, the time
required for vertical movement of the heddle frames can be
minimized.
-
By moving the heddle frames up and down in accordance
with the shedding pattern in the normal weaving operation, a
warp yarn strain given by the vertical movement can be made
closer to the warp yarn strain given by the normal weaving
operation.
-
Rendering the heddle frames to a synchronous relation
to the main shaft after moving the heddle frames up and down
is advantageous as follows. The shedding pattern after
restart of the loom can be securely shifted to the shedding
pattern before stop of the loom even in such a condition that
the weaving operation of the loom is suspended by electric
power outage with the result that a synchronous relation of
the heddle frames to the main shaft is collapsed, or that the
heddle frames are independently and arbitrarily moved up and
down without considering a synchronous relation to the main
shaft. It should be appreciated that the heddle frames are
rendered to a synchronous relation to the main shaft based on
the cycle number corresponding to the restart position and
the crank angle of the main shaft so as to attain a desired
shedding pattern in the normal weaving operation.
-
In the above arrangement, moving the heddle frames up
and down by a certain number of times (the number is an
integer) makes it possible to securely return the heddle
frames to the initial position before start of the vertical
movement where the heddle frames have been set to a
synchronous relation to the main shaft upon termination of
the vertical movement. This arrangement can dispense with a
synchronizing operation after the vertical movement. Note
that the loom is so designed that the heddle frames are
stopped in a synchronous relation to the main shaft.
-
These and other objects, features and advantages of the
present invention will become clear upon a reading of the
following description of the preferred embodiments thereof,
taken in connection with the accompanying drawings, in which:
- FIG. 1 is a block diagram schematically showing an
entire system of a loom embodying the invention;
- FIG. 2 is a block diagram showing essential elements of
a control system of the loom;
- FIGS. 3A and 3B are diagrams showing a weaving pattern
and a shedding pattern, respectively;
- FIG. 4 is a timing chart of controlling operation of
the loom;
- FIG. 5 is a chart showing a relationship between time
and operation of a heddle frame;
- FIG. 6 is a block diagram schematically showing
essential elements of a modified control system;
- FIG. 7 is a block diagram schematically showing another
modified control system; and
- FIGS. 8A and 8B are timing charts showing altered
operations of the control system.
-
-
Referring to FIG. 1, a loom includes a shedding motion
section provided with a normal operating device 11, a
synchronizing device 12 , a vertical driving device 13, and a
driving controller 21. In FIG. 1, a tension roller R1
disposed at a feeding side of warp yarn Y, a reed R2 , and a
guide roller R3 disposed 'at a winding side of fabric Ya are
exemplified as primary elements of the loom. The warp yarns Y
form a shed by four heddle frames WF. Each of the heddle
frames WF is driven by a driving mechanism WM including a
dedicated driving motor M and a crank mechanism.
-
A crank angle provided from an encoder EN coupled to
a main shaft A of the loom is inputted to the normal
operating device 11 as a pulse train signal. The main shaft A
is coupled to an unillustrated main motor. A stop signal Sa
is inputted from an unillustrated loom control circuit to the
normal operating device 11. The normal operating device 11
outputs to the driving controller 21 a target rotating amount
Poi (i=1, 2, 3, 4) for driving the corresponding driving
motor M as a pulse train signal. Outputs from the driving
controller 21 are individually sent to the respective driving
motors M. The actual rotating amount Pf of the corresponding
driving motor M is fed back to the driving controller 21.
-
The synchronizing device 12 receives a restart signal
Sb from the loom control circuit (not shown) and a current
position Gi (i=1, 2, 3, 4) of the corresponding heddle frame
WF, as well as the crank angle provided from the encoder EN.
The current position Gi represents a current height of the
relevant heddle frame WF which is detected based on the
rotated position of the corresponding driving motor M. The
synchronizing device 12 outputs to the driving controller 21
an adjusted rotating amount Psi (i=1, 2, 3, 4) for
correctively driving the corresponding driving motor M as a
pulse train signal. The synchronizing device 12 receives an
output such as Ksi from the normal operating device 11, which
will be described in a later section.
-
As shown in FIG. 2, the vertical driving device 13
includes a vertical movement command section 13a, a first
setting section 13b, and a second setting section 13c. The
vertical movement command section 13a receives the restart
signal Sb from the loom control circuit (not shown), and
outputs to the driving controller 21 a rotating amount Pq for
moving the corresponding heddle frame WF up and down as a
pulse train signal. When the integrated pulse number
corresponding to the rotating amount Pq reaches a
predetermined target rotating amount Pqm outputted from the
first setting section 13b, the vertical movement command
section 13a stops outputting the rotating amount Pq to the
driving controller 21. The vertical movement command section
13a determines the pulse frequency of the rotating amount Pq
based on a velocity vq of moving the heddle frame WF up and
down. The velocity vq is outputted from the second setting
section 13c.
-
The normal operating device 11 has a memory storing,
for example, a weaving pattern (see FIG. 3A) of fabric Ya
which is formed in terms of one repeat consisting of a
certain number of cycles (cycle number n=1, 2 , ... , 6) with
use of four heddle frames WF (frame number m=1, 2, 3, 4), and
a predetermined shedding pattern Ksi (i=1, 2, 3, 4) (see FIG.
3B) of each heddle frame WF which is defined based on the
weaving pattern. The heddle frames WF are numbered in the
order of m=1, 2, 3, 4 from the reed R2 toward downstream with
respect to the warp yarn feeding side. Referring to FIG. 3A,
it should be appreciated that the heddle frame of the number
m and at the cycle number n indicated by a square with a
cross is shifted to an uppermost position, whereas the heddle
frame indicated by a blank square is shifted to a lowermost
position for forming and closing a shed.
-
While the loom is in a normal weaving operation, the
crank angle is outputted from the encoder EN to the normal
operating device 11 in response to rotation of the main shaft
A. Upon receiving the crank angle , the normal operating
device 11 specifies the cycle number n (n=1,2, ..., 6) in one
repeat of a designated weaving pattern based on the crank
angle , and updates (increments) the cycle number n.
Further, the normal operating device 11 is allowed to output
the target rotating amount Poi of each driving motor M to the
driving controller 21 in conformity to the crank angle .
Upon receiving the target rotating amount Poi, the driving
controller 21 controls the relevant driving motor M in such a
manner that the actual rotating amount Pf of the relevant
driving motor M attain the target rotating amount Poi. Under
the control of the driving controller 21, each driving motor
M moves the corresponding heddle frame WF upward or downward
based on the shedding pattern Ksi so that the heddle frames
WF are moved up and down in synchronism with rotation of the
main shaft A for forming and closing a shed.
-
If a weft yarn insertion failure occurs at the cycle
number n=n1 during a normal weaving operation of the loom,
the stop signal Sa is generated from the loom control circuit
to suspend driving of the main motor so as to suspend the
weaving operation of the loom. Upon receiving the stop signal
Sa, the normal operating device 11 is allowed to store the
incremented cycle number n=n1+1 at the time when the weaving
operation of the loom is suspended. This is for the reason
that if a weft yarn insertion failure occurs, a loom is
generally controlled to suspend a next weft yarn insertion
and to stop the weaving operation when the loom is brought to
a next cycle. In suspending weaving operation of the loom,
driving of each driving motor M is suspended together with
driving of the main shaft A while keeping a synchronous
relation to the main shaft A.
-
In restarting the loom for normal weaving operation,
the main shaft A is rotated in a backward direction for pick
finding to the position where the weft yarn insertion failure
occurred at the cycle number n=n1, while keeping the
functions of the normal operating device 11 and the driving
controller 21. After the pick finding and removal of the
defective weft yarn, the main shaft A is rotated further in
the backward direction to the restart position corresponding
to the cycle number n=n1 - 1. At this time, the normal
operating device 11 decrements the cycle number n based on
the crank angle in conformity to the backward rotation of
the main shaft A from the stop position to the restart
position. As shown in FIG. 4, in response to generation of
the restart signal Sb in the loom control circuit, the loom
is controlled to proceed to a normal weaving operation by the
normal operating device 11 after vertical movement of the
heddle frames WF by the vertical driving device 13 and
synchronizing operation by the synchronizing device 12 are
implemented in this order.
-
Specifically, referring to FIG. 4, upon receiving the
restart signal Sb, the vertical movement command section 13a
of the vertical driving device 13 outputs, to the driving
controller 21, the rotating amount Pq for moving the relevant
heddle frame WF up and down at the pulse frequency which is
defined based on the velocity vq outputted from the second
setting section 13c. This operation is performed in the
condition: t ≧t1. Upon receiving the rotating amount Pq, the
driving controller 21 drives the relevant driving motor M
based on a constant rotating speed corresponding to the
velocity vq of the relevant heddle frame WF in such a manner
that the heddle frames WF are moved up and down altogether
without a pause in accordance with a specific vertical
movement pattern dedicatedly used for the heddle frames WF.
This operation is implemented under the condition: t1≦t<t2.
During this operation, a sufficient strain is given to the
warp yarns Y. It should be appreciated that each velocity vq
is so regulated that the rotating speed of the corresponding
driving motor M during the vertical movement falls in the
range from 50 to 200% relative to the rotating speed of the
motor M during a normal weaving operation.
-
When the integrated pulse number of the rotating amount
Pq reaches the predetermined target rotating amount Pqm, the
vertical movement command section 13a suspends the output of
the rotating amount Pq to stop driving the relevant motor M
so as to terminate the vertical movement of the corresponding
heddle frame WF at the time t=t2. It should be appreciated
that merely the operation of a single heddle frame WF is
illustrated in FIG. 4.
-
Subsequently, the synchronizing device 12 reads the
current cycle number n, namely, the cycle number n=n1 - 1
corresponding to the restart position, as well as the
shedding pattern Ksi from the normal operating device 11, and
finds the shedding pattern Ksi=f(n, ) based on the crank
angle corresponding to the restart position. Then, the
synchronizing device 12 calculates the adjusted rotating
amount Psi of the relevant driving motor M that enables the
corresponding heddle frame WF at the current position Gi to
attain the required shedding pattern Ksi, and outputs the
calculated rotating amount Psi to the driving controller 21.
This operation is implemented under the condition: t ≧ t2a,
wherein t2a - t2 ≒ 0. Upon receiving the adjusted rotating
amount Psi, the driving controller 21 drives the relevant
driving motor M by the adjusted rotating amount Psi to bring
the corresponding heddle frame WF to a synchronous relation
to the main shaft A during the time t2a ≦ t<t3. Thus, the
required shedding pattern Ksi is realized. It should be noted
that the heddle frame WF is shifted to a lowermost position
to be rendered to a synchronous relation to the main shaft A
in FIG. 4.
-
In FIG. 4, the velocity of the heddle frame WF during a
synchronizing operation may be the same as the velocity vq of
the heddle frame WF during a vertical movement or may be
faster or slower than the velocity vq, as far as the heddle
frame WF is securely rendered to a synchronous relation to
the main shaft A. Alternatively, the time (t3 - t2a) required
for a synchronizing operation may be minimized by
automatically selecting the driving direction of the heddle
frame WF for the synchronizing operation that secures a less
adjusted rotating amount Psi for attaining the required
shedding pattern Ksi, in place of making the driving
direction of the heddle frame WF for the synchronizing
operation identical to the driving direction during the
vertical movement, as shown in FIG. 4.
-
After restart of the loom, the loom is proceeded to a
normal weaving operation in which each heddle frame WF is set
to such a position as to continue the shedding pattern Ksi
before the loom is suspended by rotating the relevant driving
motor M in conformity to the rotation of the main shaft A by
way of the normal operating device 11 during the time t≧t3.
-
Alternatively, after the vertical driving device 13
moves the heddle frames WF up and down, the synchronizing
device 12 may bring the heddle frames WF to a synchronous
relation to the main shaft A without suspending the heddle
frames WF during the time t2≦t<t3 in FIG. 5. In FIG. 5,
merely the operation of a single heddle frame WF is
illustrated, and the heddle frame WF is shifted to an
uppermost position during a synchronizing operation to be
rendered to a synchronous relation to the main shaft A by
driving the heddle frame WF in the same direction as in the
vertical movement at a speed slower than the velocity vq. The
synchronizing device 12 outputs the adjusted rotating amount
Psi of the relevant driving motor M required for attaining
the shedding pattern Ksi based on the current position Gi of
the corresponding heddle frame WF at the time when the
vertical movement of the heddle frame WF is terminated.
-
In this embodiment, the loom is so designed that the
heddle frames WF are suspended in a synchronous relation to
the main shaft A even if the loom is suspended due to a
reason other than weft yarn insertion failure such as
shortage of warp yarn and forcible manual stop operation. In
restarting the loom in such a condition, the loom is returned
to a normal weaving operation by setting the main shaft A to
the restart position after eliminating the cause of
suspending operation of the loom, and by moving the heddle
frames WF up and down so as to render all the heddle frames
WF to a synchronous relation to the main shaft A.
-
If the loom is suspended owning to electric power
outage, there is a likelihood that the loom is suspended in
an asynchronous state to the main shaft A because the
rotating amount of the main shaft A resulting from inertia
force is not identical to that of the respective driving
motors M resulting from inertia force. Further, it is highly
likely that the weft yarn inserted immediately before the
power outage has insertion failure. Even in such a case, the
heddle frames WF are rendered to a synchronous relation to
the main shaft A with use of the synchronizing device 12, and
pick finding is conducted to remove the defective weft yarn.
After setting the main shaft A to the restart position, and
moving each heddle frame WF up and down by the vertical
driving device 13 to render all the heddle frame WF to a
synchronous relation to the main shaft A again, the loom is
proceeded to a normal weaving operation.
-
In the above embodiment, it is possible to move at
least one heddle frame WF up and down by the vertical driving
device 13, in place of moving all the heddle frames WF. In
such an altered arrangement, the synchronizing device 12
performs synchronizing operation merely with respect to the
relevant heddle frame WF. Further, it is possible to move the
heddle frames WF up and down individually in accordance with
a vertical movement pattern individually set for each of the
heddle frames WF by providing a vertical driving device 13
for each of the driving motors M. In such an altered
arrangement, a smoother separating operation of the warp
yarns Y can be effectuated by, for example, moving the heddle
frames WF up and down in such a manner that the adjoining
heddle frames WF are set in opposite phase to each other, or
by simply moving the adjoining heddle frames WF up and down
alternately.
-
The normal operating device 11 has a function of
storing a unit shedding pattern Ksj (j=1, 2, ... ) which is
defined per cycle, and a shedding pattern Ksi in one repeat,
which is a combination of a plurality of unit shedding
patterns Ksj, in place of storing a shedding pattern Ksi
which is defined with respect to each of the heddle frames WF,
and a function of creating a shedding pattern Ksi of each of
the heddle frames WF based on the combination of the unit
shedding patterns Ksj. Since the unit shedding pattern
Ksj=f ( ) is usable in common among the heddle frames WF at
the cycle number n, there is no need of providing a memory
having an exceedingly large capacity capable of storing an
increased number of the heddle frames WF and an increased
number of the cycles constituting one repeat.
-
Alternatively, the vertical driving device 13 may allow
each heddle frame WF to automatically return to its initial
position where the heddle frame WF is in a synchronous
relation to the main shaft A by moving the relevant heddle
frame WF up and down by a certain number i of times (i is an
integer). This arrangement makes it possible to omit
synchronizing operation by the synchronizing device 12 which
is implemented after the vertical movement. Each heddle frame
WF is controlled to be moved up and down exactly by the
number i of times by setting in the first setting section 13b
the predetermined target rotating amount Pqm which is equal
to an integral multiple of the actual rotating amount Pf of
the corresponding driving motor M required for reciprocating
the heddle frame WF once.
-
In the following, described are modifications of the
embodiment with reference to FIGS. 6 through 8. It should be
appreciated that elements in the modifications identical to
those in the embodiment are denoted at the same reference
numerals.
-
Referring to FIG. 6, a pseudo crank angle a is
outputted from a vertical movement command section 13a to a
normal operating device 11, in place of the arrangement that
the vertical driving device 13 outputs the rotating amount Pq
for moving the relevant heddle frame WF up and down to the
driving controller 21. The pseudo crank angle a is a pulse
train signal having the same waveform as a crank angle
provided from an encoder EN (not shown). In the altered
arrangement, the vertical movement command section 13a in a
vertical driving device 13 activates driving motors M by way
of the normal operating device 11 and a driving controller 21
by outputting to the normal operating device 11 the pseudo
crank angle a of a pulse frequency which is defined based on
a velocity vq of a relevant heddle frame WF so as to move the
heddle frames WF up and down in accordance with a shedding
pattern Ksi during a normal weaving operation.
-
As shown in FIG. 6, a time tq during which a relevant
heddle frame WF is moved up and down is set in a first
setting section 13b of the vertical driving device 13, in
place of setting the predetermined target rotating amount Pqm
for moving the relevant heddle frame WF up and down. In such
an altered arrangement, the vertical movement command section
13a outputs the pseudo crank angle a or the rotating amount
Pq during the time tq so as to move the relevant heddle frame
WF up and down.
-
Further, as shown in FIG. 6, a synchronizing device 12
inputs an original point signal Sci (i=1, 2, 3, 4) indicating
the initial position of each heddle frame WF in place of
inputting the current position Gi of each heddle frame WF. In
such an altered arrangement, the synchronizing device 12
outputs a signal corresponding to a moved amount of each
heddle frame WF from its initial position to such a position
as to attain a required shedding pattern Ksi=f(n, ) in terms
of an adjusted rotating amount Psi of each driving motor M.
Specifically, after activating each driving motor M and
receiving the original point signal Sci, the synchronizing
device 12 rotates each driving motor M by the adjusted
rotating amount Psi to render each heddle frame WF to a
synchronous relation to a main shaft A. Thus, a required
shedding pattern Ksi is provided.
-
Referring to FIG. 7 showing another modification, the
heddle frames WF are moved up and down by a common driving
motor M by way of a common driving mechanism WM such as a cam
mechanism. The driving mechanism WM is coupled to the driving
motor M by way of a clutch CL1, and is coupled to a main
shaft A by way of a clutch CL2. The driving mechanism WM has
a function of controlling shedding operation during a normal
weaving operation. In such an altered arrangement, the normal
operating device 11 is omitted. Further, the clutch CL2 is a
so-called one-point clutch which is selectively coupled to
the main shaft A at a specific crank angle .
-
In the above modification, in response to suspending
operation of the loom, the driving motor M is coupled to the
driving mechanism WM by way of the clutch CL1, and at the
same time, linkage of the driving mechanism WM to the main
shaft A is released by way of the clutch CL2. Then, a
vertical driving device 13 outputs to a driving controller 21
a rotating amount Pq for moving the relevant heddle frame WF
up and down to move the heddle frames WF up and down
altogether in accordance with a shedding pattern Ksi during a
normal weaving operation by way of the driving motor M and
the driving mechanism WM. Further, the driving controller 21
sets the driving mechanism WM to such a position as to be
engageable with the clutch CL2 by way of the driving motor M
in response to receiving the adjusted rotating amount Ps from
the synchronizing device 12 so as to render the heddle frames
WF to a synchronous relation to the main shaft A. The loom is
brought to a restart state after engaging the clutch CL2 with
the driving mechanism WM to couple the driving mechanism WM
to the main shaft A while disengaging the clutch CL1 from the
driving motor M.
-
In the above modifications, the velocity vq of moving
each heddle frame WF up and down which is set in the second
setting section 13c is properly determined depending on the
kind of warp yarn Y and weft yarn. Further, as shown in FIGS.
8A and 8B, a vertical driving device 13 may drive a driving
motor M at a varied speed in place of driving the driving
motor M at a constant speed. Specifically, the vertical
driving device 13 may stepwise (see FIG. 8A) or continuously
(see FIG. 8B) change the rotating speed v of each driving
motor M during a vertical movement of the heddle frames WF by
altering the rotating amount Pq for moving the relevant
heddle frame WF up and down or the pulse frequency of the
pseudo crank angle a in time-series.
-
As described above, a sufficient strain is given to
warp yarns by moving the heddle frames up and down while
keeping the main shaft non-rotated in restarting weaving
operation of the loom. This arrangement is advantageous in
eliminating a drawback that constant weft yarn density is not
secured in the vicinity of a cloth fell immediately after
restart of the loom and in effectively suppressing formation
of a filling bar in the fabric resulting from a varied weft
yarn density at the restart of the loom.
-
As this invention may be embodied in several forms
without departing from the spirit of essential
characteristics thereof, the present embodiment is therefore
illustrative an not restrictive, since the scope of the
invention is defined by the appended claims rather than by
the description preceding them, and all changes that fall
within metes and bounds of the claims, or equivalence of such
metes and bounds are therefore intended to be embraced by the
claims.