Device for removing a thread, with rotatable ring and rotatable boom for clamping an end of the thread

A device for removing a thread includes a rotatable ring and a rotatable boom. THe rotatable boom is displaceable toward the rotatable ring to clamp an end of the thread between the inner surface of the rotatable ring and the outer surface of the rotatable boom. The device also includes a driver for (1) displacing the rotatable boom toward the rotatable ring to clamp the end of the thread between the inner surface of the rotatable ring and the outer surface of the rotatable boom and (2) rotating the rotatable boom while the end of the thread is clamped between the inner surface of the rotatable ring and the outer surface of the rotatable boom.

BACKGROUND OF THE INVENTION 1. Field of the Invention 
The invention relates to a device for removing a thread. The invention also 
relates to a weaving machine. 
2. Description of the Related Art 
A jet weaving machine which includes a device for removing an improperly 
picked weft thread is known. The device is mounted at the inlet side of 
the shed between the machine's main inserting nozzle and profiled reed, 
outside the weft path. The device consists of a winding unit formed of 
winding and rotary members coaxially mounted in a tubular case. The 
winding member is rotatably mounted and slides axially on a bar within a 
sliding bearing. The rotary member is rotatably mounted in ball bearings 
and is driven through gears by a motor. 
A free end of the winding member is provided with a circumferential conical 
winding surface. The rotary member has a conical recess and a rotary shaft 
The shape of the conical winding surface of the winding member corresponds 
to the shape of the conical recess of the rotary member. 
The conical recess of the rotary member communicates with an ejecting 
channel within the rotary member's shaft. The ejecting channel opens into 
a waste box. A nozzle is centrally located within the winding member and 
is directed toward the ejecting channel. The nozzle is connected to a 
bushing for distributing pressurized fluid. 
The winding and rotary members face each other within the tubular case. A 
suitable gap separates the winding and rotary members. The winding and 
rotary members are both axially aligned with the longitudinal axis of the 
weft inserting nozzle. A guiding tube is mounted transversely to the case. 
The guiding tube opens into the case at a position corresponding to the 
gap between the winding and rotary members. A guiding nozzle is mounted 
against the orifice of the guiding tube outside the weft path such that 
the weft path is situated therebetween. 
To withdraw an improperly picked weft from the shed, weft is fed from the 
inserting nozzle and blown by the guiding nozzle into the guiding tube 
and, by means of the nozzle in the winding member, into the ejecting 
channel of the rotary member. Thereafter, weft feeding from the inserting 
nozzle is stopped and an auxiliary cutter (situated between the nozzle and 
the guiding tube) separates the weft. The winding member is then displaced 
toward the rotary member until the conical surfaces contact each other. 
The motor then begins to rotate the rotary member through the gearing such 
that the rotary member rotates the winding member (which is in contact 
therewith). As a result, the improperly picked weft is wound onto the 
conical surface of the winding member and is withdrawn from the shed back 
toward the main nozzle in a single length. 
After the improperly picked weft is wound onto the conical surface of the 
winding member, the fuzz ball thus created is blown by the nozzle of the 
winding member through the ejecting channel and into the waste box. 
The above-described device for removing an improperly picked weft is 
disadvantageous because of its positioning at the inlet to the shed. To 
weave under constant conditions, the device must be positioned outside the 
weft path, thus complicating the drawing-in of the thread into the winding 
unit. 
Moreover, the thread is drawn back directly in a single length without 
first being released from the interlacing point of the fabric. Thus, 
particularly with delicate yarns, there exists the danger of surpassing 
the limiting stress of the thread, causing the weft to break before being 
completely withdrawn. This danger is enhanced because the weft rubs 
excessively against an edge of the guiding tube as it changes direction 
through the guide tube while being withdrawn. 
Moreover, the rigid mechanical gearing of the winding unit cannot 
compensate for increased tensile stress in the weft caused, e.g., when the 
thread is locally trapped. This also causes the improperly picked weft to 
break. Thus, the means for driving the rotary member increases the 
exacting character of the prior art design. 
Moreover, the position of the ejecting nozzle within the winding member is 
inefficient because pressurized fluid acts initially only upon the free 
end of the improperly picked weft. This can cause the winds of the fuzz 
ball to tighten on the conical surface of the winding member such that the 
wound up weft fuzz ball cannot be transported into the waste box. 
SUMMARY OF THE INVENTION 
The invention is directed to a device for removing a thread, including: (A) 
a rotatable ring with an inner surface; (B) a rotatable boom with an outer 
surface, the rotatable boom being displaceable toward the rotatable ring 
to clamp an end of the thread between the inner surface of the rotatable 
ring and the outer surface of the rotatable boom; and (C) driving means 
for (1) displacing the rotatable boom toward the rotatable ring to clamp 
the end of the thread between the inner surface of the rotatable ring and 
the outer surface of the rotatable boom and (2) rotating the rotatable 
boom while the end of the thread is clamped between the inner surface of 
the rotatable ring and the outer surface of the rotatable boom, the 
driving means being directly operatively connected to the rotatable boom. 
Preferably, the thread is an improperly picked weft thread. Preferably, the 
inner surface of the ring is an inner conical surface, the outer surface 
of the boom being an outer conical surface Preferably, the ring, the boom, 
and the driving means are coaxial with each other, the boom being axially 
displaceable toward the ring. Preferably, the driving means includes 
displacing means for axially displacing the boom and a pneumatically 
reactive driving unit for rotating the boom, the displacing means and the 
reactive driving unit being adapted to be driven by a common source of 
pressurized air. Preferably, the displacing means includes a stationary 
piston and a cylinder partially surrounding the piston, the cylinder being 
connected to the boom so as to be axially displaceable and rotatable with 
the boom. Preferably, the reactive driving unit includes a hollow arm 
which extends in a radial direction with respect to the axis of the 
driving means, the arm having an outlet hole which is directed 
transversely with respect to the radial direction, the reactive driving 
unit being adapted to direct air through the arm and the hole to rotate 
the boom. Preferably, the reactive driving unit includes a centrifugal 
governor for controlling the angular velocity of the boom. Preferably, the 
arm includes a limiting nozzle directed oppositely with respect to the 
outlet hole, the reactive driving unit including a control weight slidably 
located on the arm, the control weight being adapted to selectively cover 
the outlet hole to control the angular velocity of the boom. 
Preferably, the device further includes a stationary nozzle for (1) 
directing pressurized air through the ring to draw the end of the thread 
into position to be clamped between the boom and the ring and (2) 
directing pressurized air across the outer conical surface of the boom to 
blow the thread from the boom and through the ring. Preferably, the ring 
includes a second conical surface, the conical surfaces of the ring 
forming a diffuser which is adapted to cooperate with the nozzle to draw 
the end of the thread into position to be clamped between the boom and the 
ring. Preferably, the nozzle is located in the vicinity of the conical 
surface of the boom and is inclined with respect to the axis of the boom. 
Preferably, the device further includes a magnet for urging the ring toward 
the conical surface of the boom. Preferably, the device further includes 
an opening for cooperation with the ring, the ring being movable into and 
out of engagement with the opening, the magnet being adapted to urge the 
ring into engagement with the opening. Preferably, the magnet is 
stationary with respect to the opening, the ring including a central 
portion which extends within the magnet and a radially extending contact 
surface located underneath the magnet. 
The invention is also directed to a weaving machine, including: (A) an 
inlet side of a shed, an outlet side of the shed, and inserting means for 
inserting weft threads through the shed along a weft path, the inserting 
means being located at the inlet side; and (B) a device for removing an 
improperly picked weft thread from the shed, the device being located at 
the outlet side, the device including: (1) a rotatable ring with an inner 
surface; (2) a rotatable boom with an outer surface, the rotatable boom 
being displaceable toward the rotatable ring to clamp an end of the 
improperly picked weft thread between the inner surface of the rotatable 
ring and the outer surface of the rotatable boom; and (3) driving means 
for (a) displacing the rotatable boom toward the rotatable ring to clamp 
the end of the improperly picked weft thread between the inner surface of 
the rotatable ring and the outer surface of the rotatable boom and (b) 
rotating the rotatable boom while the end of the improperly picked weft 
thread is clamped between the inner surface of the rotatable ring and the 
outer surface of the rotatable boom. 
Preferably, the driving means is directly operatively connected to the 
rotatable boom. Preferably, the device is located in the weft path. 
Preferably, the machine is a jet weaving machine, the inserting means 
including an inserting nozzle. 
The preferred embodiment is advantageous because of its simple design and 
its ability to operate without an external mechanical drive. To evenly 
withdraw the weft, the device provides a constant angular velocity and a 
torque which can be readily adjusted by air pressure control. A further 
advantage of the device is the positioning of the blow off nozzle, whereby 
reliable removal of the weft fuzz ball is obtained. 
Other features and advantages of the invention will become apparent from 
the following description of a preferred embodiment of the invention, with 
reference to the accompanying drawings

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A device 38 in accordance with the preferred embodiment of the invention is 
mounted in the weft path on the end side of a weaving machine shed 37. The 
device 38 is fastened outside of the range of operation of a beat-up reed 
39. 
The device 38 includes a body 1 and a hub 2 which is slidably mounted 
within the body 1. A shaft 4 is rotatably mounted in a cylindrical 
interior of the hub 2 by a pair of radial bearings 3. The bearings 3 are 
braced inside the hub 2 by a tubular clearance filler 5. 
In a lower part of the device 38, a boom 7 is fastened to the shaft 4 by a 
screw 6. The boom 7 has an outer conical surface 8. The boom 7 is 
displaceable into engagement with an inner conical surface 9 of a contact 
ring 10 which is mounted in the body 1. The contact ring 10 is biased 
toward the body 1 by a magnet 11. Another conical surface 12 of opposite 
conicity cooperates with the inner conical surface 9 of the ring 10 and 
forms a diffuser therein. A free part of the outer conical surface 8 
engages the inner conical surface 9 in a weft inlet hole 13. The inner 
conical surface 9 forms, together with the conical surface 12, an opening 
14 through the ring 10 and a suction chamber 15 in the bottom of the body 
1. The suction chamber 15 is connected to a suction mechanism (not 
illustrated) by a hose 16. A sensor 17 is located at the orifice of the 
inlet hole 13. The sensor 17 records the presence of the improperly picked 
weft 36. A pneumatic nozzle 18 communicates with the inlet hole 13 through 
an inclined opening. The opening of the nozzle 18 is directed toward the 
opening 14. 
An upper part of the hub 2 extends as far as the inner circumference of a 
cylindrical shell 19 which is fastened to the body 1. The shell 19 is 
covered by a cover 20. In the central part of the cover 20, a hollow 
projection is drawn into the device 38 to form a stationary piston 21 of 
an air damper 22 for displacing the rotatable boom 7. A cylinder 23 of the 
damper 22 is loosely positioned on the piston 21 and fastened to the shaft 
4 of the boom 7. Four hollow arms 24 of a reactive driving unit 25 project 
radially from a lower part of the cylinder 23. Each arm 24 has a blindage 
26 located at its end. Each blindage 26 extends beyond the outer 
circumference of each respective arm 24. 
Each arm 24 has a transversal outlet hole 27 in the vicinity of its 
blindage 26. The outlet holes 27 form nozzles for rotating the driving 
unit 25. The outlet holes 27 are commonly situated so as to cooperate to 
rotate the unit 25 in a winding direction. Each arm 24 also has an 
opposite direction limiting nozzle 28 which opens into the hollow of the 
arm 24. The nozzles 28 are directed oppositely relative to the outlet 
holes 27. A control weight 29 is displaceably mounted on each of the arms 
24. The control weights 29 form a centrifugal governor 30 for controlling 
the angular velocity of the driving unit 25. The faces of each control 
weight 29 are beveled. Bevels toward the sides of the blindages 26 are 
internal and, from the side of the cylinder 23, external. 
At rest, the rotatable boom 7 is inserted into the hollow of the body 1 by 
a coil spring 31 mounted in a circular groove 32. One end of the spring 31 
is supported against the bottom of the circular groove 32 and the other 
end is supported against an enlarged part of the hub 2. In the rest 
position, the upper end of the cylinder 23 is situated in a circular 
groove 33 in the cover 20. An opening 34 is provided in the cover 20 to 
permit pressurized air to freely exit during operation of the driving unit 
25. The damper 22, driving unit 25, and centrifugal governor 30 thus 
constitute the device's driving mechanism. 
The free end of the improperly picked weft 36 is first sucked into the 
device 38 by the pneumatic nozzle 18 and the diffuser (the opening 14). 
The weft 36 is sucked in through the inlet hole 13, through the opening 
14, and into the suction chamber 15. Thereafter, pressurized air is 
introduced through the piston 21 and into the cylinder 23. The pressurized 
air overcomes the resistance of the coil spring 31 and displaces the 
rotatable boom 7 into the inlet hole 13. Thus, the outer conical surface 8 
of the rotatable boom 7 comes into contact with the inner conical surface 
9 of the ring 10 such that the end of the weft 36 is stationarily clamped 
therebetween. 
Displacing the rotatable boom 7 into engagement with the contact ring 10 
causes the contact ring 10 to be removed from the permanent magnet 11. 
Simultaneously, as the compressed air begins to flow out through the 
transversal outlet holes 27 of the arms 24, the reactive driving unit 25 
begins to rotate the boom 7. The driving unit 25 rotates the rotatable 
boom 7 at a constant angular velocity. That is, as the rotational speed of 
the boom increases, the control weights 29 of the centrifugal governor 30 
are displaced radially outwardly by centrifugal force, thus closing the 
outlet holes 27. Simultaneously with the displacement of the control 
weights 29, the oppositely directed limiting nozzles 28 reduce the angular 
velocity of the boom 7. As the velocity decreases, the pressurized air 
acts on the inner bevels of the control weights 29 to overcome their 
centrifugal force and to displace the control weights 29 inwardly. Thus, 
an equilibrium state is obtained. In this manner, the weft 36 is wound 
onto the rotatable boom 7 at an absolutely uniform, guaranteed angular 
velocity without impacts. If necessary, the torque of the rotatable boom 7 
can be easily adjusted by controlling the pressure of the air entering the 
driving unit 25. The torque is independent of the angular velocity of the 
rotatable boom 7. 
While winding the improperly picked weft 36, the contact ring 10 is removed 
from the magnet 11 and rotates in its magnetic field with the boom 7 
without any undesirable friction Yet the weft 36 remains clamped between 
the conical surfaces 8 and 9 by the constant force of the magnetic field. 
After winding is completed, introduction of pressurized air into the 
cylinder 23 is stopped and the coil spring 31 returns the rotatable boom 
7, together with the driving unit 25, to the rest position. When the boom 
7 returns to the rest position, the ring 10 again bears against the magnet 
11 such that the outer conical surface 8 and the inner conical surface 9 
no longer engage each other. 
The fuzz ball is then removed by introducing pressurized air into the 
pneumatic nozzle 18 such that the air flows over the outer conical surface 
8 of the rotatable boom 7 and through the opening 14 of the ring 10. The 
weft 36 is sucked into the suction chamber 15 and exits the device through 
the hose 16. 
The magnet 11, which retains both the ring 10 in the body 1 of the device 
38 and clamps the ring 10 to the boom 7 while permitting free rotation 
therewith, can be either a permanent magnet or an electromagnet. The 
magnet 11 can be a continuous ring, or it may be formed of separate bodies 
distributed about the circumference of the body 1 in the vicinity of the 
opening 14. 
The device specified above can be used in all types of weaving machines. 
Its position with respect to the weaving machine need not be only in the 
weft path. 
Although the invention has been described in connection with a preferred 
embodiment thereof, many variations, modifications, and other uses will 
become apparent to those skilled in the art. It is preferred, therefore, 
that the invention be limited not by the specific disclosure herein, but 
only by the appended claims.