1. WARP STOP MOTION
Alisha Komal
Roll no# F16TE10
Textile engineering department
Mehran university of engineering and technology
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2. WARP STOP MOTION:
Introduction:
Warp stop motion may be define as, the stop of loom when a warp thread
break. OR
Warp stop motion stop the loom immediately when a warp thread break
during weaving process.
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3. Purpose of warp stop motion:
The main purpose of warp stop motion is to stop the loom when
warp end break or warp thread excessively loose. So that the
unrepeatable faults is avoided.
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4. Reason :
If the breaking of warp thread is not detected immediately, then the loose
thread will tend to become entangled round adjacent thread to break and
create a faults known as a flat in fabric.
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5. Mechanism of warp stop motion:
The system is activated by light weight metallic drop wires which have profile shaped.
Two such drop wires or dropper are used. The large slot at the top is for the movement
of the reciprocating bars which are used both in mechanical or electrical warp stop
motion.
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6. Types of drope wires or dropper:
1. Open-ended drope wire
2. Closed-ended drope wire
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7. 1. Open ended drope wire:
It can be used after the beam gaiting as it has
an open ended hole.
2. Closed ended drope wire:
It can be used when a single end is passed
through a drawing in process .
Types of warp stop motion:
Mechanical warp stop motion
Electrical warp stop motion
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8. MECHANICAL WARP STOP
MOTION
In a mechanical warp stop motion one
reciprocating bar moves (to and fro )in between
the stationary bars .the stationary bars serve the
purpose of holding the drop wire. The drop wire
are supported by a warp thread.
In case of end breakage the drop wire will lose
support from the tight yarn or(warp thread)and
will fall due to gravity. if its fall due to lowest
possible height ,then the reciprocating (back and
forth) movement of the reciprocating bar is
obstructed and the loom is stopped.
This motion is carried out on a conventional
looms. 1/28/2019
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9. MECHANICAL WARP STOP MOTION ON SHUTTLE LOOM
A=ECCENTRIC CAM
B=BOTTOM SHAFT
C=RECIPROCATING BAR
D=FORK LEVER
E=CONNECTING ROD
F=OSCILLATING SHAFT
G=SPRIING
H=FIXED BAR
I=DROP PIN
J=BARS
K=HITTER
L=L - SHAPED LINK
M=CROSS ROD
N=CROSS LEVER
O=KNOCK OFF ROD
P=STRIKER
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11. The eccentric A is fitted on the bottom shaft B rocks the vibrating bar to and
fro through a fork lever D connecting rod E ,oscillating shaft F.
The fork lever D and a connecting rod E are connecting through a spring G
so that the motion imparted to the vibrator bar..
The two side of the vibrator bar has five vertical serrations on each side of
the vibrating bar there is a fixed bar H having vertical serrations on the inner
side.
The drop wires are supported by a warp threads. The slots of the drop wire are
passes through the bar J.
The j bars are stationary and serve the purpose of holding the Drop wires in
the event of end breakage.
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12. Under the normal condition the bottom end of the drop wires are
clear Of the path of the oscillating bar which makes to and fro
movement. Between the fixed bars during the one complete
revolution of the bottom Shaft.
This movement gives complete up and down movement to the hitter
through L-Shaped link L connecting rod M cross lever N and knock
of rod O.
whenever the drop wire falls down on the drop wire bar to a warp
breakage the path of vibrating bar is obstructed.
When its movement is obstructed the hitter K is in the middle of its
path.
The striker P on the slay hits the hitter and the slay moves forward
and the loom is stopped.
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13. ELECTRICAL WARP STOP MOTION
In an electrical warp stop motion the drop
wires acts as a element that that makes or
breaks an electrical circuit.
In case of warp break, the drop wire falls
freely on bar and will complete an
electrical circuit ,thus , activates solenoid.
The solenoid will attract a bar which will
be hit by the knock-off lever. As a result
the bar will disengage the starting handle
through some other lever which is
providing voltage to the main circuit for
running machine. This type is mainly used
in non conventional looms.
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14. In case of warp break, the drop wire falls
freely on bar and will complete an
electrical circuit ,thus , activates
solenoid. The solenoid will attract a bar
which will be hit by the knock-off lever.
As a result the bar will disengage the
starting handle through some other lever
which is providing voltage to the main
circuit for running machine. This type is
mainly used in non conventional looms
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15. CIRCUIT MAKE:
Circuit Make or close circuit:
In the case of circuit make there is a
conduction bar through which current
is flowing. Droppers are hang on warp
yarns and are slightly upward from this
conducting bar. When the warp end
breaks, the drop wire will fall on this
conducting bar (both being conducting
material) ,then maximum current will
pass and the circuit will become short
circuit. 1/28/2019
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16. CIRCUIT BREAK OR OPEN CIRCUIT
In the case of open circuit , there is a
conducting wire rail and dropper. When
the dropper falls on this conducting rail.
Its circuit get disturbed and the signal
will be generated. position of the bar
will be interrupted which stops the
machine immediately.
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18. BENEFITS OF WARP STOP MOTION:
To provide better quality of fabric warp stop motion plays vital role.
1. In the case of excessively loose thread , the warp yarn entangles
with neighboring yarns. Thus generates fault to the fabric.
2. If the warp end is missing in case of yarn breakage , the line space
appears on fabric , which hinders the quality of product.
3. This motion is sensed through sensors, hence less time is required
for removing the fault.
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