_AUTOMATIC WEFT-REPLENISHING DEVICES_
The history of the development of the power-loom, from its inception
by Dr. Cartwright, has been written on many occasions. That story
relates how old methods have been improved or else displaced by new
ones of greater efficiency, and how the modern power-loom has, by the
effort and skill of the pioneers of industry, been brought gradually
to its present state of mechanical perfection. This march of progress
goes on steadily, continuously, and almost imperceptibly to those who
are not immediately interested in or affected by the changes that are
thus wrought; until by some special circumstance they suddenly and
unexpectedly arrest attention, and it is realized for the first time
that a new era has dawned and promises changes of great magnitude.
The advent, now fifteen years ago, of what are popularly described
as “automatic looms” marked the beginning of events of considerable
importance to the weaving industry in particular, and to the textile
industry in general. The essential element which distinguishes these
looms from those of ordinary construction consists of special apparatus
attached to, and forming an integral part of, the looms, which are
thereby enabled to replenish weft automatically from a reserved supply
conveniently held in readiness. This briefly constitutes the automatic
element of the looms. There are, of course, many auxiliary attachments
that are incidental to the weft-replenishing devices, and which
increase their efficiency and productiveness.
Notwithstanding the comparatively short period that has elapsed since
the adoption, on a commercial scale, of these looms, such has been the
activity of inventors and loom-makers both at home and abroad, that
looms of this class have already been designed in an almost endless
variety of forms, some of which differ essentially in construction
and operation, whilst many others differ only in minor details of
construction. Most of these, however, have never matured to practical
forms. Many have never escaped the secret confines of the experimenting
room. Others have been doomed to premature failure, whilst some three
or four types of real merit are struggling hard for supremacy. Which
of the competing types will win, ultimately, is at the present time
matter for conjecture. This will depend entirely on the type that will
best meet the requirements of manufacturers, and the one that will
endure the test of experience and time, which alone can be the deciding
factors. But, for certain classes of fabrics for which they are
suitable, it is safe to predict that automatic looms of some approved
type are permanently established in the trade.
Whatever particular character these weft-replenishing devices assume,
they may be broadly classified under one or other of two distinct
types, namely, (1) that in which the same common shuttle is replenished
with cops or bobbins of weft; and (2) that in which a fresh shuttle
replaces the previous one. Each of these two broad divisions comprises
numerous modifications in both their construction and also in the
manner in which they operate.
Of the cop-or bobbin-changing type of loom, the “Northrop” loom,
invented in Hopedale, Mass., U.S.A., by James H. Northrop (a native of
Keighley, Yorks.), has gained a greater measure of success than that
of any other automatic loom; and of the shuttle-changing type, the
“Hattersley” loom, invented by Simeon Jackson, of Geo. Hattersley and
Sons, Limited, Keighley, Yorks., has probably found greater favour than
others of that type. Looms of the Northrop type require essentially
the use of shuttles of special construction that are capable of
self-threading the weft; whereas looms of the Hattersley type may
weave with the same kind of shuttles as those employed in ordinary
power-looms. Looms of both types are constructed so that the change
of weft is effected instantaneously whilst they are running at full
speed, without any loss of time; but when a change of weft takes place
in the Hattersley modification of the shuttle-changing type, the looms
stop running automatically for a few picks to allow more time for the
changing of shuttles, after which the looms re-start automatically and
continue running at full speed.
In addition to the essential elements constituting a successful
weft-replenishing device, this requires to be supplemented by numerous
appliances of a special character to ensure the general efficiency
of the loom. For example, at that side of the loom on which the
replenishment of weft is made, there is fixed a weft-cutting device
to sever the superfluous trail of weft close to the selvedge of
cloth after the insertion of each fresh supply of weft. In some
looms the weft is replenished only when the previous supply fails
either by breaking or becoming exhausted; and some are furnished with
“weft-feeler” motions to put the weft-changing mechanism into operation
and thus replenish the weft just before the previous supply is entirely
depleted, thereby preventing broken or missing picks of weft which
would produce faulty cloth. A warp-stop motion, which is sometimes
applied to ordinary looms, is an almost indispensable accessory to an
automatic loom. Its function is to detect the breakage of warp-ends,
and to stop the loom automatically whenever that occurs. These remarks
apply also to the controlling of the tension and delivery of the warp,
which are sometimes effected automatically in looms of any description.
Up to the present time weft-replenishing devices are almost exclusively
restricted to single-box looms employed in the production of standard
varieties of fabrics of comparatively simple construction, and
containing but one kind of weft requiring the use of only one shuttle.
These devices have, however, been employed on check-looms weaving
with more than one kind of weft, and therefore requiring the use of
a corresponding number of shuttles at the same time; but automatic
check-looms have not yet passed the experimental stage and become
established on a commercial basis, although there are prospects of this
taking effect in the near future.
Having thus far introduced the reader to what constitutes the chief
elements of an automatic or self-acting loom, it will, at this stage,
and before examining the details of their special mechanism, be both
instructive and profitable to briefly survey the work of pioneers in
this sphere of invention, as revealed in the records of the numerous
Letters Patent that have from time to time been granted for inventions
of devices for the automatic replenishing of weft in looms, and to
trace the origin and development of such devices from the earliest
authentically recorded date of their inception down to the present time.
From a research of the earliest published records of patents relating
to weaving, which records date from 15th July, =1620=, it would appear
that the credit for the first patent for an automatic weft-replenishing
device for looms is due to Messrs. John Paterson Reid and Thomas
Johnson, both of Glasgow, who are the joint patentees of an invention
of such a device described in the Patent Specification, dated 20th
March, =1834=, No. 6579. This is a large document of 69 pages of text
comprising over 35,000 words and 12 sheets of diagrams. It describes in
a very lucid manner several improvements in power-looms, of which that
relating to the automatic replenishing of weft is treated almost as if
it were regarded, by the inventors, as of only secondary importance to
the other improvements which they describe.
In view of the great progress which has been made within recent years
in the development of these looms, and also in consideration of the
fact that a patent, which was granted to Charles Parker nearly seven
years subsequently, and is described in the Specification dated
22nd October, =1840=, No. 8664, has been frequently cited as the
first patent relating to the automatic supply of weft in looms, the
first-named document acquires a special interest, not only as a record
of what is probably the first attempt in that direction, but also
because it establishes, beyond refutation, the date and rightful title
to the first patent granted for such an invention.
In the former specification, the patentees state that their
improvements are applicable to what were then known as Johnson’s
vertical power-looms, in which the warps were extended vertically
from the warp-beam at the bottom to the cloth-roller at the top of
the loom; and the reed, which served as the shuttle-race during the
flight of the shuttle through the warp-shed, moved in a vertical plane
when beating up the weft. These vertical looms were made double, to
permit of two pieces of cloth being woven in them at the same time;
but they had evidently been discarded, and were not then in use
amongst manufacturers. The looms made according to Reid and Johnson’s
specification were so very different from Johnson’s looms as to have
very little in common with them excepting that they also were vertical
power-looms in which the warps extended vertically. The specification
states that the “great object” of their improvements is to enable
=four= webs or pieces of cloth to be woven simultaneously and at
one operation in the same loom, with only one slay which has a vertical
motion, and also that the warps for the four webs are to be wound
on two separate warp-beams. After describing in minute detail the
construction of the improved loom, the patentees proceed to describe
their invention of a device for the =automatic supply of weft to
their looms whilst these continue running=. This part of their
invention is introduced as if it were quite incidental and of little
consequence, and is described as the “accessories and new improvements”
which they apply to their vertical power-looms, as follows:--
“In order to avoid stopping the motion of the loom when any one of the
=four= weft threads break, twice or three times as many shuttles as
are required for constant use are to be lodged in suitable receptacles
or shuttle boxes, which are so arranged that the =breaking of a weft
thread will cause a change of shuttles, and a substitution of spare
shuttles, which have been provided and placed in the said receptacles
ready for such changing=; for instance, the breaking or failure of a
weft thread from either of the two shuttles, which work on the same
reed as one pair, will cause the pair to be removed, and a pair of
spare shuttles to be brought into their place instantaneously, without
any act of the person who attends the loom, and who will therefore
have no occasion to stop the motion thereof when a weft thread breaks
or runs off, but will only have to take care to keep the loom at all
times provided with a sufficient number of spare shuttles ready filled
and inserted into their proper places in the receptacles, leaving it
to the machinery of the loom to remove those shuttles which have been
working, and to substitute others the instant that a change becomes
necessary in consequence of the breakage or failure of weft thread.
But if, by neglect of the attendant, the loom is not so provided with
a pair of spare shuttles ready filled and placed in preparation for
changing as aforesaid by the machinery on the breakage or failure of
any weft thread, then the loom will stop its own motion, wherefore the
weaving cannot be continued unless all the four webs have their several
wefts duly inserted in a proper manner for working cloth.” From this
description it is of interest to note that what probably constituted
the first automatic loom was of the shuttle-changing type, to which
nearly all subsequent inventors in this particular field have chiefly
devoted their attention.
It was not until an interval of nearly seven years had elapsed after
Reid and Johnson’s patent that a patent was granted to Charles
Parker, of Darlington, for the second invention of an automatic
weft-replenishing device, which, like its predecessor, was also one of
the shuttle-changing type. This device, along with other improvements
in power-looms, is described and illustrated in the specification dated
22nd October, =1840=, No. 8664, in which the fourth claim made by the
patentee is in respect of “means of changing the shuttle when the weft
is broken or the shuttle is empty of weft” without the necessity of
stopping the loom for that purpose.
The next and third patent for an automatic weft-replenishing device,
which, like the two previous devices, was a shuttle-changer, was
that granted to an agent, William Newton, to whom the invention was
communicated from a foreign country not named in the specification
which is dated 28th April, =1852=, No. 14,092. This document states
that the invention relates to improvements in looms for weaving plain,
figured, or fancy fabrics, and that it consists in the employment of
several shuttles arranged in the loom in such a manner that if the
weft failed, or the shuttle missed or flew out of the shuttle-box, a
second shuttle would always be in readiness to take its place, without
it being necessary to stop the loom in order to replace it with a
fresh shuttle. In carrying out the improvement, several shuttles where
placed one above the other in a box, or in guides fixed immediately
above the shuttle-race or box, and held in their place by means of
a stud, plate, or catch, which, when required, was removed so as to
allow a second shuttle to enter the shuttle-box in place of the spent
shuttle, which, by the same motion, was pushed out. In the event of
a shuttle flying out or missing the shuttle-box, the same mechanism
caused a fresh shuttle to supply its place. The special mechanism which
affected the changing of shuttles was put into operation by means of a
weft-stopping device which detected the absence of weft whenever this
failed to pass along the shuttle-race in front of the reed.
After an interval of five years from the granting of the previous
patent, Patrick McFarlane, of Perth, patented an automatic
weft-replenishing device which marks a distinctly new departure from
the previous inventions for the same object, and one, moreover,
which has the distinction of constituting the prototype of cop-or
bobbin-changing devices, of which type a modification has been so
successfully adopted in the construction of Northrop automatic looms.
McFarlane’s invention is described in the Patent Specification dated
13th April, =1857=, No. 1046, which states that “the first part of the
invention consists in means or arrangements by which a loom is made
to supply its shuttle or shuttles with fresh weft when the weft last
placed in the shuttle or shuttles has become broken or exhausted.” The
cop or bobbin of weft was placed in a case which fitted inside the
shuttle in which it was held securely during weaving, but from which it
could be easily ejected and replaced by another weft-case containing a
fresh supply of weft whilst the loom continued weaving. Any practicable
number of these weft-cases were conveniently stored and retained in a
suitable receptacle or hopper, so that the successive weft-cases could
take the place of those removed, as they were each in turn inserted in
the shuttle. The chamber containing the reserve supply of weft-cases
was attached to the framing of the loom opposite the shuttle-box or
boxes, so that when the absence of weft was detected by the weft-fork,
this put into operation the weft-changing mechanism which forced a
weft-case from the hopper into the shuttle, and thereby displaced the
previous weft-case which fell into a box or basket.
An interval of only three years elapsed before the next patent was
granted for a weft-replenishing device patented by Thomas Ingram, of
Bradford, for which the specification is dated 4th April, =1860=, No.
861. In this specification, the patentee describes a device which
combines the elements of both a shuttle-changing and also a cop-or
bobbin-changing loom. The invention relates to mechanism for effecting
a continuous action in looms without stopping them to change the
bobbins or cops, or for an additional supply of weft, whether that is
all used up or only broken. This was effected by forming an opening
or aperture in the front, back, top or bottom of the shuttle-box
“large enough to admit a shuttle, or a case containing a spool or
spools of weft, to pass through to be inserted within the box.” Also,
“when the weft is broken or used up, or a change of weft is required,
the shuttle, or the case within the shuttle containing the weft, is
immediately expelled through one of the openings in the shuttle-box,
and supplied through another of the openings with another shuttle or a
case containing a further supply of weft.” The patentee states later
that he is aware of a patent for a previous device “to exchange the cop
of weft by means of a portable case, whilst the loom was in action,”
and does not claim that device as a part of his own invention; but what
he claims “is the combination and the general arrangement of apparatus
or mechanism for producing or effecting continuous action in looms for
weaving.”
A device of a different character from any of those previously
described was one that formed the subject of a communication from
Julius Boeddinghaus, of Elberfeld, Prussia, to an agent, William
Brookes, and is described in the specification dated 14th November,
=1860=, No. 2787. The function of this device was merely that of
=ejecting= the shuttle automatically when the weft failed; but the
replenishing of weft required to be performed by hand in the usual
manner. The ejecting of the shuttle was effected by causing it to shoot
downward through an opening in the base of the shuttle-box at one end
of the slay, and on the occurrence of which the loom would stop.
A patent for the next device which, although not strictly belonging to
the present category of inventions, is, nevertheless, closely allied to
them, was that granted to John Leeming, Bradford, and described in the
specification dated 5th February, =1861=, No. 301. The specific object
of this device was to effect changes of weft of different kinds or
colours for the production of check fabrics. Weft-cases, as introduced
by Patrick McFarlane in =1857=, were employed to contain the weft,
and the weft-cases were exchanged automatically in the =same shuttle=
according to a prearranged scheme of decoration, but not on the failure
of weft, in which event the loom would stop as usual. The device was,
therefore, a checking motion to effect changes of different kinds of
weft by changing cops or bobbins, instead of employing a number of
separate chambers, each containing a shuttle with a different kind of
weft, and bringing these in line with the race-board, as required. In
this respect, therefore, the present device may be regarded as the
first recorded attempt to adapt the automatic weft-replenishing element
to perform the function of a checking motion.
The next following patent for a weft-replenishing device was that
granted to three Crawfords and Robert Templeton, of Beith, Ayr, and
described in the specification dated =17th= February, =1862=, No. 419.
This invention, which is of the shuttle-changing type, introduces
two distinctly novel departures from any previous invention of the
same class, namely, the employment of a six-chambered revolving
shuttle-box to bring fresh shuttles into working position, and also
what corresponds to a weft-feeling motion to effect the replenishing
of weft before the supply in use is quite depleted. The chambers of
the multiple shuttle-box are charged with reserve shuttles contained
in a hopper. At each change of shuttles the boxes revolved on
their common axis for one-sixth of a revolution to receive a fresh
shuttle in readiness for the next change. On arriving at the bottom
of its circuit, the discarded shuttle fell out of its chamber into
a receptacle. The weft-feeling motion operated the weft-changing
mechanism when the weft was nearly depleted. This was effected by
constructing the weft pirns or bobbins with a longitudinal slot to
receive a curved blade-spring fitting inside the shuttle so that it
entered the slot in the bobbin and passed underneath the weft. On the
weft becoming exhausted to a certain fixed point on the bobbin, the
blade-spring was automatically released, on which it projected through
a slot formed in the shuttle side. Thus, on the shuttle arriving in
its chamber of the rotary boxes, the blade-spring came into contact
with a part of the weft-changing mechanism which was thereby put into
operation to change the shuttles.
The foregoing brief descriptions of the first eight patented devices
for the automatic replenishing of weft in looms will serve to indicate
the general character which those devices assumed down to February,
=1862=. Although since that date to the present time the number of
patents for devices of that class of inventions number many hundreds,
yet it is significant that none of these later devices differ in any
essential element from those of earlier inventions. The table on
page 209 gives a list of weft-replenishing devices for which Letters
Patent have been granted, down to =1894=, with the date and number of
specification, the names of patentees, and type of device.
LIST OF PATENTS FOR AUTOMATIC WEFT-REPLENISHING DEVICES.
--------------------+--------------+--------------------------+----------------------------
| No of | |
Date of Patent. |Specification.| Name of Patentee. | Type of Device.
--------------------+--------------+--------------------------+----------------------------
(1) 1834, Mar. 20 | 6,579 | J. P. Reid and T. Johnson| Shuttle-changing
(2) 1840, Oct. 22 | 8,664 | Charles Parker | Shuttle-changing
(3) 1852, Apr. 28 | 14,092 | William Newton | Shuttle-changing
(4) 1857, Apr. 13 | 1,046 | Patrick McFarlane | Cop- or Bobbin-changing
(5) 1860, Apr. 4 | 861 | Thomas Ingram | Shuttle-changing }
| | | or Cop- or }Optional.
| | | Bobbin-changing }
(6) 1860, Nov. 14 | 2,787 | Julius Boeddinghaus | Shuttle-ejecting
(7) 1861, Feb. 5 | 301 | John Leeming | Bobbin-changing
| | | for Check Fabrics
(8) 1862, Feb. 17 | 419 | H., J., and R. Crawford | Shuttle-changing
| | and R. Templeton |
(9) 1863, Jan. 27 | 239 | J. Edmondson and T. | Cop- or Bobbin-changing
| | Ingram |
(10) 1864, Mar. 17 | 688 | J. Edmondson and T. | Cop- or Bobbin-changing
| | Ingram |
(11) 1864, July 19 | 1,803 | John Maynes | Cop- or Bobbin-changing
(12) 1865, Feb. 2 | 293 | John Maynes | Cop- or Bobbin-changing
(13) 1865, Sept. 20 | 2,395 | Joseph Edmondson | Shuttle-changing
(14) 1866, Jan. 1 | 1 | J. Bullough and W. | Shuttle-changing
| | Rossetter |
(15) 1866, Apr. 16 | 1,069 | Alf. Vincent Newton | Shuttle-changing
(16) 1866, Sept. 6 | 2,292 | John Bullough | Shuttle-changing
(17) 1866, Oct. 13 | 2,654 | Wm. Rossetter | Shuttle-changing
(18) 1868, July 28 | 2,366 | John Bullough | Shuttle-changing
(19) 1868, Sept. 10 | 2,788 | John Maynes | Shuttle-changing
(20) 1869, Sept. 28 | 2,820 | John Bullough | Shuttle-changing
(21) 1870, May 26 | 1,530 | Benjamin Cooper | Shuttle-changing
(22) 1872, Mar. 12 | 757 | A. M. Clark, from Paul | Shuttle-changing
| | Heilmann |
(23) 1874, May 1 | 1,542 | J. H. Johnson, from | Shuttle-changing
| | Arthur Villeminot |
(24) 1877, Jan. 27 | 356 | J. S. and B. A. Raworth | Semi-automatic
| | | Shuttle-changing
(25) 1888, Mar. 31 | 4,850 | Jacob Jucker | Shuttle-changing
(26)} {| 10,633 |}A. G. Brookes, from {| Cop- or Bobbin-changing
(27)}1891, June 23 {| 10,634 |} W. F. Draper {| Shuttle-changing
(28)} {| 10,635 |} {| Cop- or Bobbin-changing
(29) 1894, Apr. 26 | 8,251 | H. Bourgeois | Shuttle-changing
(30) 1894, Oct. 2 | 18,611 | G. O. Draper | Cop- or Bobbin-changing
(31) _1894, Nov. 27_| _22,939_ | _A. G. Brookes, from | _Northrop device for
| | W. F. Draper_ | Cop- or Bobbin-changing_
--------------------+--------------+--------------------------+----------------------------
During the periods of four years ending December, =1900= and
=1904=, there were 34 and 163 British patents respectively
granted for inventions relating to devices for the replenishing of
weft automatically in looms, which figures bear striking evidence of
the amount of energy and inventive talent which have been expended in
this direction during the past few years. And how forceful are these
figures when contrasted with the number of patents (31) extending over
the first period of 61 years. It was, however, not until after the
advent, in =1894=, of the Northrop automatic loom, which received
such favourable reception by American manufacturers, that the adoption
of automatic looms was taken into earnest consideration by British
manufacturers, many of whom now recognize that in one form or another
such looms have a definite sphere of usefulness in the manufacture of
a great variety of different classes of fabrics of simple construction
and embodying one series each of warp and weft threads.
=The Northrop Weft-replenishing Device.=
The most characteristic features and essential elements of this device,
and also those which distinguish it from all previous inventions of
this class, consist of the removal of cops or bobbins of weft that
are conveniently retained in a =circular rotary hopper= or
magazine, and of their insertion into a =self-threading shuttle=,
by mechanical means operated automatically either on the breakage or
depletion of weft, or else when the weft is depleted to a predetermined
amount, as may be elected. The magazine containing the reserve
supply of weft is always mounted above the shuttle-box situated on
the right-hand side of the loom, as represented perspectively in Fig.
167, which shows a bobbin-hopper A from which a pusher B is in the act
of removing a full bobbin of weft and inserting it into the shuttle,
thereby ejecting the previous bobbin C which falls down a chute into a
box D.
[Illustration: FIG. 167.]
[Illustration: FIG. 168.]
The parts of this device are better represented by the sectional view
shown in Fig. 168, which illustrates a cop-hopper A freely mounted on a
stud E to permit of its partial rotation, intermittently, immediately
after each successive change of weft, so as to bring into position
another cop to be in readiness for the next change of weft. The hopper
here shown is one constructed with sockets for 28 cops, F; but the
space occupied by the pusher reduces its actual capacity to 25 cops.
These are previously placed upon skewers, G, of special construction,
after which they are disposed in a horizontal position around and
between the rims of two discs or plates that are formed with notches
for the reception of the skewers, as represented in the diagram.
The conditions under which a change of weft is effected depends
entirely on the equipment of the loom, which may be adapted so that a
change will take place only when the weft either breaks or otherwise
fails in its supply; or else the loom may be furnished with an
attachment known as a “weft-feeling” device which effects a change of
weft immediately before the previous supply is completely consumed,
albeit, in this case, if the weft should break, the loom will stop
automatically, as under ordinary conditions. The object of this device
is to avoid such defects as are liable to be caused in cloth in
consequence of broken and missing picks of weft, and so produce cloth
of superior merit. If, however, such a device is not employed, the
weft-changing mechanism is put into action, on the failure of weft,
by the weft-fork hammer pulling backward the weft-fork, as usual. But
whether the operation of the weft-changing device is controlled by
the weft-fork or by the weft-feeler, the object in either case is to
cause the notched and free end of a trip-finger H to tilt upward from
its normal position, as shown in the diagram, so that on the forward
stroke of the slay K the finger will be struck by a bunter J fixed on
the front of the slay-baulk. The trip-finger is loosely mounted on a
stud fixed at the bottom of a short arm of an L-lever which constitutes
the pusher B, fulcrumed freely on a stud L. Thus, in the event of the
trip-finger being tilted on the forward stroke of the slay, the free
end of the pusher, which reaches over the ready-positioned cop in the
hopper, is suddenly depressed when the slay is at its extreme _forward_
position, thereby removing that cop from the hopper, and forcing
it into the shuttle M, through the bottom of which the previous
cop-skewer is expelled and passed down a chute N. The next flight of
the shuttle causes the weft thread to pass through a slit formed in a
brass casting fixed in the upper side of the shuttle, and then to enter
the shuttle eye automatically. At the same time, the remnants of both
weft threads are severed near to the selvedge of cloth and also at a
point near to the hopper, so that they shall not become obstructive
or involve the risk of being carried along accidentally into the
warp-shed. All these operations occur in proper rhythmical sequence
whilst the loom continues to run at full speed, which, for a loom of 36
inches reed-space, may be up to 150 picks per minute.
=The Hattersley Weft-replenishing Device.=
(_Patent No. 22,523, 11th December_, 1900.)
The chief characteristic element which distinguishes this device--which
is one of the most successful modifications of the shuttle-changing
type--from other weft-changing devices, is the stopping of the loom
to effect the change of shuttles, and then the restarting of it,
automatically. The object of that course is to allow more time to
accomplish the change, and so avert the straining and breaking of the
mechanical parts, which are more liable to occur when the changing of
weft is effected whilst the loom continues to run at full speed, as in
all other automatic looms. It is also claimed that this arrangement
enables a loom to be run at the same speed as an ordinary loom of the
same width and construction, whereas continuous-acting looms require to
be worked at a slower velocity.
[Illustration: FIG. 169.]
[Illustration: FIG. 170.]
In the Hattersley loom, the reserve supply of shuttles that have been
previously furnished with weft are retained in a hopper or magazine
which is mounted on the breast-beam and facing the shuttle-box on
either the right-or left-hand side of the loom. The changing of
shuttles may be effected either by the action of the weft-fork only
when the weft actually fails from any cause, or else by the operation
of a weft-feeler, before the weft completely fails, as desired. In
either case a change of shuttles involves a series of six distinct
operations which occur in the following sequence, namely: (1) stopping
the loom, (2) raising the shuttle-box fender, (3) ejecting the
failing shuttle from its box, (4) removing from the magazine another
shuttle and placing it in the emptied shuttle-box, (5) lowering the
shuttle-box fender back into its normal position, and (6) restarting
the loom. These operations, of which the second, third, and fourth are
represented by diagrams in Figs. 169, 170, and 171, are accomplished by
means of a series of four tappets governed by an indented clutch-wheel,
all of which are loosely mounted together on the second-motion or
picking-shaft, at the same side of the loom as that on which the
driving-pulleys are situated. The clutch-wheel is driven by means of a
pinion carried by the loose driving-pulley, and revolves continuously,
so that when a change of shuttles is called for, an indent or notch
in the clutch-wheel becomes engaged by a lug which, being secured to
the tappets, turns these for one revolution, and thereby performs the
series of operations just enumerated. Thus, in the event of weft either
failing or becoming nearly depleted, either the weft-fork hammer or
else the weft-feeler motion, according to the equipment of the loom,
first disengages the starting-handle to pass the driving-belt from
the fast or driving-pulley to the loose pulley, thereby stopping all
the primary movements of the loom, and at the same time putting into
operation the series of four tappets which effect the changing of
shuttles. Then one of the four tappets raises the shuttle-box front, C,
above the shuttle B, as shown in Fig. 169, to permit of the removal of
the shuttle. A second tappet then operates the pusher D, which advances
to eject the discarded shuttle from its box, whence it falls into a
receptacle, as shown in Fig. 170. A third tappet next operates the
feeder E, which removes the bottom shuttle from the hopper A and places
it in the same shuttle-box as that previously occupied by the ejected
shuttle, as represented in Fig. 171. The shuttle-box fender now falls
sufficiently to prevent the withdrawal of the newly inserted shuttle
from the box as the feeder withdraws and returns to the magazine to
receive another shuttle in readiness for the next change, after which
the shuttle-box front falls to its normal position, and finally the
fourth tappet replaces the starting-handle into its operative position
to transfer the driving-belt back again from the loose to the fast
driving-pulley and thereby re-start the loom.
[Illustration: FIG. 171.]
All the movements just described are performed during one complete
revolution of the tappets, and involve a stoppage for six picks,
corresponding to six revolutions of the crank-shaft. Therefore, in
a loom running at a speed of 180 picks per minute, the changing of
shuttles would involve a stoppage of the loom for only two seconds.