U.S. patent number 3,693,904 [Application Number 05/095,396] was granted by the patent office on 1972-09-26 for weft bobbin stand.
This patent grant is currently assigned to Sulzer Brothers Limited. Invention is credited to Robert Bucher.
United States Patent |
3,693,904 |
Bucher |
September 26, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
WEFT BOBBIN STAND
Abstract
There is disclosed, for use with looms in which the weft supply
remains outside the shed, a wheeled weft bobbin stand including a
weft bobbin creel, weft thread brakes, and intermediate weft thread
storage devices.
Inventors: |
Bucher; Robert (Winterthur,
CH) |
Assignee: |
Sulzer Brothers Limited
(Winterthur, CH)
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Family
ID: |
4383393 |
Appl.
No.: |
05/095,396 |
Filed: |
December 4, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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756900 |
Sep 3, 1968 |
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Foreign Application Priority Data
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Sep 6, 1967 [CH] |
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12479/67 |
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Current U.S.
Class: |
242/131;
139/450 |
Current CPC
Class: |
D03D
47/00 (20130101) |
Current International
Class: |
D03D
47/00 (20060101); B65h 049/02 (); D02h 001/00 ();
D03j 005/08 () |
Field of
Search: |
;242/131,131.1
;139/122,128 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Christian; Leonard D.
Parent Case Text
This application is a continuation of Ser. No. 756,900, filed Sept.
3, 1968 and now abandoned.
Claims
I claim:
1. A movable weft bobbin stand comprising a base, means to support
a plurality of bobbins on the base, and at least one intermediate
weft thread storage device mounted on the base, each of said
devices including a substantially cylindrical body rotatably
mounted from one end thereof whereby a weft thread wound onto said
body may be pulled off the other and thereof, means to wind a weft
thread onto said body, and means to energize said winding means to
maintain on said body a number of turns of weft thread between
limiting minimum and maximum values.
2. A movable weft bobbin stand according to claim 1 including
wheels for support of said base.
3. A movable weft bobbin stand according to claim 2 including a
brake operating on the wheels thereof.
Description
The present invention pertains to a movable weft thread bobbin
stand for looms of the type in which the weft thread supply is
retained outside the shed, and more particularly for looms of this
type in which wefts of different yarn types or colors are employed,
successive wefts being pulled off the end of weft bobbins of the
various types or colors of yarn for picking through the shed in a
specified sequence and being picked through the shed after passing
through intermediate weft thread storage devices on which there is
stored at least the length of thread necessary for one pick.
In known looms the weft bobbin creel is disposed in the vicinity of
the weaving plane on the picking side of the loom, either in fixed
position or swingably on a hinged supporting frame. This
construction makes it difficult to obtain access to certain
portions of the loom such as the heddle driving mechanism, the
picking mechanism, the yarn feeding device, weft tensioner and
pull-back mechanism, the heddle reversing mechanism and, especially
in looms employing plural wefts, the weft change mechanism.
It has been proposed, in the copending application of Erwin
Pfarrawaller entitled WEFT BOBBIN CREEL, Ser. No. 752,714 filed
Aug. 14, 1968, now U.S. Pat. No. 3,526,253 assigned to the assignee
hereof, to support the weft thread bobbins on a creel affixed to
the loom frame in a position above the picking mechanism of the
loom. In the apparatus disclosed in that application, the bobbins
are disposed in one or more superposed approximately circular
arrays about a vertical axis on inwardly directed stub shafts. The
threads pulled off the ends of the bobbins pass through
thread-guiding eyes in the vicinity of the axis of the creel and
thence downwardly through a hollow hub out of the creel and through
weft thread brakes.
Intermediate weft thread storage devices have moreover been
proposed, especially for use in looms operating at high picking
rates. Such a device pulls the thread from the supply bobbin at a
speed low compared to the speed at which the weft is picked through
the shed and maintains on a drum a length of thread sufficient for
at least one pick, so that when the pick occurs the thread can be
pulled off the end of the drum at the very high speed required by
the actual picking operation. Apparatus of this kind is disclosed
in the copending application of Erwin Pfarrwaller entitled WEFT
THREAD SUPPLY APPARATUS FOR GRIPPER SHUTTLE LOOMS, Ser. No.
584,131, filed Oct. 4, 1966, and assigned to the assignee hereof,
now U.S. Pat. No. 3,411,548.
Provision on the loom of a weft bobbin creel and of intermediate
weft thread storage apparatus however restricts access to various
parts of the loom structure on the picking side thereof. The
present application is intended to surmount this difficulty. It
provides a movable weft bobbin stand which includes a creel and
intermediate weft thread storage apparatus through which the weft
threads pass from the bobbins to the picking mechanism of the
loom.
The apparatus of the invention can be employed with looms not
having intermediate weft thread storage apparatus in order to fit
them for higher picking rates without necessarily removing
therefrom the original weft bobbin supporting apparatus, which
retains its utility for weaving at lower picking rates.
When cloth is to be woven with wefts of plural colors or yarn
types, there are customarily provided two weft bobbins for each
color. While thread is drawn from one bobbin of each color, the
second bobbin of that color is held in reserve, the outer end of
its thread being knotted to the inner end of the thread on the
bobbin currently in use, so that when the first bobbin is
exhausted, the thread will be automatically drawn from the second
without interruption of the weaving process. A four-color loom
therefore customarily requires at least eight weft bobbins, making
up an assembly of substantial weight and bulk.
When a loom is shifted from weaving of one type of cloth to
another, all of the weft bobbins must customarily be replaced. The
weft thread bobbin stand of the invention possesses in this respect
the advantage that such a stand can be prepared in advance for a
new type of cloth. When the type of cloth to be woven is to be
changed, the weft bobbin stand previously employed can be replaced
with a fresh one having the desired weft bobbins suitably mounted
therein, with minimum loss of weaving time.
The bobbin stand of the invention does not need to be positioned
with high accuracy with respect to its loom, the essential
requirement being simply that the threads from the several weft
bobbins or weft bobbin pairs shall pass freely from exit guide eyes
on the stand into an entrance eye or eyes on the loom.
The stand of the invention may include for each weft thread (e.g.
for each pair of weft thread bobbins) a weft thread brake, which
may be of any suitable type. These brakes are disposed downstream
of the bobbins, in the sense of weft thread motion, and their
function is to hold constant the tension of the threads as pulled
from those bobbins and to prevent premature withdrawal of coils
therefrom.
In a preferred embodiment thereof, the bobbin stand of the
invention includes for each of the separate types or colors of weft
to be woven into the cloth, or alternatively for each group of such
threads to be simultaneously picked through the shed as by means of
a common shuttle, a separate intermediate weft thread storage
device having its own exit guide eye disposed adjacent the
corresponding inlet eye of the loom.
The drive or drives for the intermediate weft thread storage
devices are desirably disposed in the stand immediately adjacent
those devices, each of those devices including desirably its own
automatic control, such as the photoelectric control disclosed in
the copending application Ser. No. 584,131, now Pat. No. 3,411,548
whereby there is maintained in storage in each of those devices a
length of thread between a minimum and a maximum. The intermediate
weft thread storage devices are driven by an electric motor or
motors connected via a flexible cable to an electric power
receptacle on the loom.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further described in terms of a
non-limitative exemplary embodiment thereof and with reference to
the accompanying drawings, in which:
FIG. 1 is an end elevation of a loom with a weft bobbin stand in
accordance with the invention, the loom being seen from the cloth
end thereof;
FIG. 2 is a view in elevation at an enlarged scale of the weft
bobbin creel of the stand of the invention, seen at an enlarged
scale and partially in cross-section;
FIG. 3 is a diagrammatic plan view of the creel of FIG. 2;
FIG. 4 is a view partly in vertical elevation and partly in
section, illustrating an intermediate weft thread storage device
which can be used in the weft bobbin stand of the invention;
and
FIG. 5 is a sectional view taken on the line 2--2 of FIG. 4.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 1, the stand of the invention is generally
indicated at 1, disposed at the picking side of a loom generally
indicated at 2. In the loom, reference character 3 identifies the
cloth beam, the picking and catching side frame members thereof
being identified at reference characters 30 and 31. The main drive
motor 4 drives the main loom shaft through a belt connection to a
combined flywheel and clutch 5. Reference character 6 identifies
heddle frames for formation of a shed. The picking mechanism is
indicated at 7 and a gripper shuttle is shown at 9 passing through
the shed to a catcher 8. One or more weft threads 23 may be
simultaneously picked through the shed by means of the same
shuttle. If narrower widths of cloth are to be woven, the catching
mechanism 8 may be moved back towards the picking side, for example
to the position indicated at 8a in dot-dash lines. After it has
been picked through the shed, the shuttle is braked to a stop in
the catcher and is returned or restored a short distance toward the
picking side of the loom in order to compensate for irregularities
in the distance required for braking. In this process the weft is
similarly drawn back toward the picking side by means of a thread
tensioner 10. It is then grasped by edge clamps not shown and cut
off on the picking side. The weft so inserted is then beaten up by
the reed and is bound into the cloth with the next shed change. The
weft ends initially extending beyond the edges of the cloth are
tucked into the next shed by means of tuck-in needles not shown and
are beaten up with the next weft to form a secure selvage. For
achievement of various forms of weave the heddles 6 are driven by a
dobby 11, for example of the card or eccentric type, which can also
control the weft feeders for selection in proper order of wefts
from the various pairs of weft bobbins 22 (FIG. 2) in the creel 13
of the stand 1 in FIG. 1. According to the prescribed succession of
weft colors, one or more wefts may be drawn in succession from the
same bobbin 22 while the other bobbins are waiting, or
alternatively the weft color or yarn type can be changed with each
pick.
In the case of high speed looms account must be taken of the fact
that the time available for picking is a small fraction of the loom
cycle. The speed of the shuttle and of the weft attached thereto is
therefore high during their passage through the shed, whereas the
end of the weft next to be inserted is practically stationary until
picking time therefor. In order to achieve dependable operation
with this discontinuous motion of the wefts, one or more
intermediate weft thread storage devices 12 are provided in
accordance with the invention in the stand 1, downstream (in the
sense of weft thread motion) of the bobbins 22 or of their
respective thread-guiding eyes 24 in the creel. These intermediate
weft thread storage devices may be of the type disclosed in the
copending application Ser. No. 584,131 now U.S. Pat. No. 3,411,548
hereinabove referred to. A weft thread brake 24a, disposed in the
stand 1 between each of the eyes 24 and its intermediate weft
thread storage device 12 serves to effect withdrawal of the weft
threads in optimum fashion and with formation of a thread balloon
between the bobbins 22 and eye 24, for delivery at substantially
constant tension through the devices 12 and the exit guide eyes 29
of the stand to the entrance eyes 32 of the loom. The devices 12
are driven by means of common motor 12a, mounted on the stand, the
motor being energized via a flexible cord l2b connecting to a power
outlet l2c on the loom. The creel 13 is fastened to the base 27 of
the stand 1 by means of a strut 14 and is so disposed that in
operating condition it is located above the thread -feeding devices
10 of the loom at the picking side thereof. The base 27 is
supported on wheels 35. As illustrated in FIG. 2, the creel 13 is
disposed above the weaving plane and is rotatable about a vertical
axis on a bearing 15.
Apparatus suitable to constitute each of the intermediate weft
thread storage devices 12 is shown in FIG. 4. The device of FIG. 4
includes a set of bearings generally indicated at 124 supported on
the arm 123. The ball bearings proper are shown at 125. A hollow
shaft 126 is supported by means of ball bearing races from the
bearing support 124. At the left end of the shaft as seen in FIG.
4, there is provided a pulley 127 mounted to turn freely on the
shaft 126. This pulley is driven by means of a belt 128 from the
drive pulley 129 of a motor 12a.
The pulley 127 has affixed thereto a clutch plate 132 which
cooperates by means of a magnetic coupling with a disc 133 fixed on
the shaft 126. The disc 133 includes electromagnets 134 which can
be energized via brushes 135 in a circuit including a switching
device 136. When the magnetic coupling is energized, rotation of
the disc 132 is imparted to the shaft 126.
At the right end of the shaft 126 as seen in FIG. 4, there is
provided an eye 137 and a bore 138 through which the weft thread
110 passes from the inside to the outside of shaft 126. This shaft
has affixed to its right end a hollow conical body 139 which
functions as a flyer arm. At the outer edge of the latter is
provided a thread-feeding eye 141 through which the weft thread is
passed.
The shaft 126 includes an extension 142 inside the hollow cone 139.
A drum 144 is rotatably supported with respect to the shaft in this
space via ball bearings 143. Whereas the shaft 126 with its end 142
rotates, the drum 144 is held stationary as will hereinafter be
further explained.
At its left end as seen in FIG. 4, the drum 144 includes a conical
enlargement 145 disposed substantially in the plane defined by the
rotating eye 141, which plane is normally vertical.
The right end of the drum 144 as seen in FIG. 4 is disposed within
a ring 146 affixed to the support arm 123 so as to leave an annular
space 147 between the ring and the drum. The ring 146 supports two
permanent magnets 148 as shown in FIG. 5. The cylinder 144 carries
two armatures or keepers 149 which cooperate with the magnets 148.
In this way the drum 144 is prevented from following the rotation
of the elements 126, 139, 141 and 142.
The support arm 123 additionally carries a light source 151 whose
beam 152 is obliquely incident on the drum 144. The reflected beam
153 impinges on a photocell 154 which is shielded from the source
151 by means of a mask 150. The photocell is connected by
conductors 155 to the switching device 136. The source 151 and
switching device are additionally connected via conductors 156 and
157 to a source of voltage 158.
The mode of operation is as follows: The motor 12a is energized
from a voltage source 130, and rotates. Hence the hollow shaft 126
rotates with its cone 139 at uniform speed. The weft thread 110 is
fed from the bobbin 22 through an eye 24 and through a thread
tensioner 164 into the hollow shaft 126. The thread emerges from
the shaft at 138 to pass outside the cone 139 and then through the
rotating eye 141 toward the axis of the shaft. By virtue of the
rotation of the cone 139 and eye 141 with respect to the stationary
drum 144, a number of turns of the weft thread are built up on the
drum. The arrangement is such that the turn nearest the eye 141 is
formed on the conical enlargement 145 of the drum. The drum has a
polished surface so that the arriving coils cause those already
wound to slip to the right in FIG. 4 and thus move onto the
cylindrical portion of the drum. After a number of revolutions have
been executed by the shaft, several such turns will build up on
that cylindrical portion. By reason of the polished nature of the
drum surface and because of the looseness with which the turns are
wound, each turn will be shifted to the right by the turn to the
left of it.
During weft thread insertion, the thread 110 is pulled off the
stationary drum 144 toward the right, in FIG. 4, passing through
the annular space 147. As may be seen from FIG. 4, no balloon of
thread forms in the region 110a. The thread then passes through an
eye 29.
The average axial length 173 of the space occupied by the turns of
thread on the drum 144, which axial length is so far as possible to
be maintained constant, is desirably made of such size that the
length of the thread wound up on the drum corresponds approximately
to the width of the cloth, i.e. to the length of one pick. If the
axial length 173 of the space occupied by the coils on the drum
extends to the right so as to cover the point 174 at which the
light beam 152 is reflected, the reflected beam 153 will be
interrupted, reflection occurring at most in a diffuse manner from
the thread on the drum. The photocell 154 and the switching device
136 are so adjusted that with this reduction of light incident on
the photocell, the supply of current to the magnetic coupling 132,
133, 134 is interrupted. The hollow shaft 126 and cone 139
accordingly come to rest and the further accumulation of thread on
the drum 144 is temporarily halted, whereas the elements 131, 129,
127 and 132 continue to rotate.
When after one or more additional picks or, according to the width
of the cloth during the course of a subsequent pick, enough coils
are withdrawn from the drum so as to uncover the spot 174 at which
the light beam is incident on the drum, the photocell will again
receive the reflected beam so that the magnetic coupling will be
restored by operation of the photocell 154 and switching device
136. The cone 139 resumes rotation so that once more the weft
thread is withdrawn from the bobbin 22 and wound up on the drum
144.
The construction of the creel itself may be of the type disclosed
in the copending application entitled WEFT BOBBIN CREEL,
above-identified. Details thereof are shown in FIGS. 2 and 3. The
creel includes a hub 16 resting on the bearing 15 with a cam 18 on
the hub and a notch 18a on the bearing to prevent inadvertent
rotation of the creel and consequent tangling of the threads.
Spoke-like arms 17 are affixed to the hub 16. At the end of each
arm there is provided a hinge 20 rotatable about a vertical axis
and having affixed thereto an arm 19 carrying at its end a stub
shaft 21. In operative position the arms 19 are substantially
tangential to the circular array of bobbins, so that the stub
shafts 21 are directed radially inward for support of the bobbins
22. In FIG. 2 two adjacent bobbins 22 are shown combined into a
pair with the inner end of the thread of the first bobbin connected
to the outer end of the second. The two bobbins of each pair are
disposed inside a screen 25 which limits the size of the thread
balloon formed from thread pulled from either of those spools. A
partition wall 26 is disposed between the two spools of each pair
with a pad of felt 26a on its upper edge and onto which there may
be laid the connecting thread between the two spools. The screen 25
and partition 26 are advantageously made of transparent material
and fastened to the arm 17. The thread, after passing through the
eye 24, passes downwardly through the hub 16 and the hollow bearing
15, through a thread brake 24a and thence to the intermediate weft
thread storage device 12 and to its exit eye 29 from the stand
1.
The stand can be fastened to the loom by means of a coupler or
linkage 28. Since however the only forces exerted between the stand
and the loom are those produced by the weft threads being pulled
from the creel, which forces are negligible, the coupling 28 can be
dispensed with and the stand can be fixed in position with respect
to the loom by means of a brake 33, operating on the wheels 35
thereof.
The invention is not limited to the embodiment disclosed. For
example, a plurality of creels 13 can be provided superposed one
above another. Moreover the bobbins 22 can be supported in a
movable stand to be positioned substantially in the weaving plane
to the left of the intermediate weft thread storage devices 12 as
seen in FIG. 1. More generally, the invention includes all
modifications of and departures from the embodiment shown properly
falling within the spirit and scope of the appended claims.
* * * * *