THE SCUTCHING MACHINE.
(66) After the cotton has been opened by any of the machines just
described it is passed into a machine commonly known as a “scutcher.”
In this it is subjected to a further beating action, which in this
case, however, has the object of cleansing rather than opening it.
Machines of this class may be either single or double, that is, the
cotton may in passing through the machine be subjected to the action of
one or two beaters. Occasionally, but very rarely now, three beaters
are used. It is becoming a more general practice to use an opener and
single beater combined as a first stage and a single beater machine as
a second stage, but there is no fixed rule in this respect, the actual
facts of each case determining the procedure. At one time the opened
cotton was ejected in a loose condition from the opener, and was placed
upon the scutching machine feed-table by hand, often being weighed. As
an English practice this is becoming obsolete, the system of pneumatic
suction being employed to convey the cotton from one machine to
another. Openers have very often attached to them a lap machine, which
forms the cotton into a roll or “lap.” As the “lap” attachment is one
which is common to most cleaning machines a description may be given of
it at this point.
(67) This attachment consists of two fluted rollers (=L L= Fig. 22),
which are suitably revolved, and on which the roll of cotton =M= is
formed, being lapped round a rod or tube by the frictional contact of
its surface with the rollers =L=. Before it reaches this point the
cotton is formed into a sheet on the dust cages, as described in the
preceding chapter. The iron rod or tube is made long enough to act as
an axis for the lap to revolve on, and to enable it to be carried about
from place to place for further treatment by succeeding machines. As
the sheet or fleece leaves the dust cages =J= it is passed between a
pair of smoothly turned rollers, the upper one of which is weighted
so as to calender or compress the lap. This is a matter of some
importance, as it renders the surface of the lap smoother and prevents
the various layers adhering to each other when unrolled. An arrangement
is fitted by which the attainment of a defined diameter of lap releases
the setting on handle, causing the latter to move and transfer the
strap on to the loose pulley stopping the machine. The importance of
forming laps is now well recognised, and will be dealt with at greater
length at the end of this chapter.
(68) Fig. 22 represents a side elevation of a single scutching machine,
as made by Messrs. Lord Brothers, that is, one which beats the cotton
once. It contains a revolving beater =A=, fixed upon a central shaft
and driven at a high velocity from a counter shaft. The beater consists
of arms, forged solid, with a central boss, and having feet at their
outer ends. The arms are keyed firmly on the shaft, and may be either
round or elliptical in shape. There are either two or three arms on
each boss, and a number of them are secured to the shaft along its
length within the beater case. According to its construction the
beater is known as a two or three “winged” beater. However made, it is
carefully shaped and machined, so as to be in perfect balance, and this
is a most important point in the construction of the machine. Too much
stress cannot be laid on the necessity for extreme care in this matter.
Not only should the beater arms be balanced prior to fixing, but after
having been keyed on the shaft the same operation should be carried
out. In order to balance the beaters thoroughly it is better to revolve
them rapidly, while sustained in bearings having freedom of sliding
movement in a frame. The velocity at which they are tested should be
considerably in excess of that at which they work, and no pains ought
to be spared to get the beater in absolutely true balance when working.
Otherwise the vibration set up would be considerable, and the character
of the blow given would be intermittent instead of regular. Before the
final balance is given the blades should be attached to the arms. The
blades are made of steel—or of a combination of steel and iron fused
together—of an irregular section, angularly formed at one side, so as
to present a moderately sharp face to the cotton as it strikes it. The
blade requires to be made with a slight clearance, so as not to rub the
cotton after striking it.
[Illustration: FIG. 22. J.N.]
(69) The question as to which is the better form of beater to use—a two
or three-winged—is one which is difficult to answer. Most makers to-day
are using the former, while others—as for instance, Messrs. Platt,
Brothers and Co.—while employing a two-winged beater for the “breaker,”
use a three-winged for the “finisher” scutching machine. From the
constructor’s point of view the two-winged beater has undoubted
advantages, as it is at once more easily made, and balanced with much
less difficulty. The diameter of a two-winged beater is usually 14
inches across the blades, and of a three-winged 16 to 18 inches. The
velocity of the former is greater than that of the latter, being in
one case 1,200 to 1,500 revolutions per minute, and in the other 900
to 1,000. Thus the peripheral velocity of the two-winged beater is
from 4,314 to 5,497 feet per minute, and that of a three-winged, 4,100
to 4,700 feet per minute. Although a three-winged beater, running at
1,000 revolutions, will strike the cotton 3,000 times per minute, the
two-winged form, running at the higher velocity of 1,500 revolutions,
will give the same number of blows. There is, however, the character
of the blow to be considered. The smaller diameter in the case of the
two-winged enables the higher velocity to be reached, and the blow
given is sharp and quick. In addition to this, the smaller circle
described by this form of beater causes the blade, after having struck
the cotton, to leave it rapidly; whereas the larger diameter of the
three-winged one leads to the blade being longer in contact with the
cotton than it otherwise would be. This, coupled to the comparative
slowness of its peripheral velocity, gives a dragging blow, which is
not a good thing for the cotton, as it is apt to crush or bruise the
fibres. The longer the staple the slower the velocity of the beater
should be, and this has an important bearing on the subject. For
instance, with good cotton, the velocity of a two-winged beater is
sometimes reduced to as low as 1,000 revolutions, while with Indian
cotton the higher velocity is preferable. These considerations tend to
show that the two-winged beater is the most suitable.
(70) There is another point which, however, deserves a word or two.
The regularity of the pulsations of a scutcher beater is a matter
requiring consideration. It is a subject not always thought of, but
it has a great influence upon the resultant lap. The cotton—as will
be hereafter shown—is struck from a roller or pedal, and is thrust
into the range of action of the beater blades at a defined and regular
rate. As it is desirable to beat it into small tufts before flinging it
on to the grids, and as the cotton is liable to damage if the pieces
struck off are too large, it follows that the oftener the blades
strike the better. That is, of course, assuming they do not strike so
often as to powder or crush the fibre. Now, there is no reason in this
consideration, for the employment of a three-bladed beater, which does
not strike the cotton more frequently than is the case with one with
two blades.
(71) It is usual to form laps at the termination of each scutching
process. These are first made, in most cases, on the opener, or failing
that, on the breaker scutcher. The laps thus made are fed to a second
machine called the finisher scutcher, where a new lap is made, which
is fed to the carding engine. It is therefore desirable to obtain
the utmost regularity in the last lap named, and for this reason the
pulsations of the beater become important. On this account Messrs.
Platt Bros. and Company use a three-winged beater in their finisher
scutcher, believing that the result is more satisfactory.
(72) Surrounding the beater at its upper portion is a case, made quite
air-tight. Beneath the beater a grid =H= is placed, the bars of which
are set to present a sharp edge to the cotton. The number of these
varies according to the class of cotton used. Careful regard should be
given to this factor. In fixing the bars they should be placed as shown
in Fig. 24. The front bars =C= should have their cleaning edges set a
little in advance of a perpendicular line drawn across an imaginary
line horizontal to the axis. The angularity thus given should decrease
as the bars are further from the feed roller. The reason of this is
obvious. As the cotton is struck from the feed rollers it is desirable
that it should receive a sharp check at once, in order to shake out
the freshly-freed impurities. This requirement becomes less urgent as
the cotton passes onward and the arrestment of its traverse is less
necessary.
(73) The circle described by the top of the bars should not be
concentric with that of the beater blades, but ought to be as shown in
Fig. 24, further from the centre of the beater shaft at the back than
it is at the front of the grid. The reason for this is that the bulk of
the cotton after being scutched becomes greater, owing to its more open
condition, and it naturally requires more room, to avoid any choking or
entanglement. Further, if the grid is comparatively long the distance
between the bars—in other words, their pitch—must be increased. Below
the bars is a chamber into which the dirt can fall freely, and which
is closed by doors from without. The pitch of the bars should be large
enough to permit of the easy passage of the dirt.
[Illustration: FIG. 23. J.N.]
[Illustration: FIG. 24.]
(74) Messrs. Howard and Bullough use, in addition to the fixed bars
shown, the additional bars =D=, which are pivoted at their lower end,
as shown, in a movable plate. This plate is attached to a lever =E=,
which can be operated from the outside. The purpose of these bars is to
admit of the admission of more or less air as desired. The space below
the fixed bars and that below the air bars are separated by a thin
division plate =F=. It is claimed for this arrangement that the fall of
the dirt through the bars =C= is considerably facilitated.
(75) After passing the dirt grids, the cotton falls on to a second
grid, or plate, as preferred, and then between a short “dead” plate
and “beater sheet” to the cage =J= on to which it is drawn. The cage
=J= consists of a skeleton cylinder revolving on a shaft, and having
its periphery formed of finely-perforated sheet metal. Each end of the
cage terminates in an air passage or trunk extending upward as shown.
At the foot of the trunk the fan =I= is placed, which exhausts the air
through the cages, and sucks the cotton on to them so as to form a
continuous sheet or fleece. From the cages the fleece is taken to the
lap attachment, which has been previously described.
(76) Messrs. Crighton and Sons, a perspective view of whose machine is
given in Fig. 25, make their cages in a somewhat different manner to
that just described. The ends of the cages are fitted into the framing,
which is recessed at each side to receive them. Their peripheries are
formed of woven wire webbing, instead of the perforated zinc sheets
mostly used. At the end of the cage the webbing is protected by a brass
ring, which keeps it firmly in position. The effect of this arrangement
is two-fold. A greater space is left for the passage of the air than
is possible with a perforated metal covering, and as a result, the
intensity of the current is reduced. In addition to this, the fleece
of cotton is laid on the whole of the face of the cages, because the
manner in which they are fitted into the framing practically causes the
latter to act as a guide, beyond which the cotton cannot spread. In
this way the edge, or “selvedge,” of the lap is rendered very even, a
subject the importance of which is further dealt with in paragraph 99.
[Illustration: FIG. 25.]
(77) Another point of special construction, adopted by the same firm,
is the position of the “dead plate.” This is the name given to a plate
below which the scutched cotton travels, extending across the machine
immediately behind the beater. As the cotton leaves the range of the
beater, it falls upon a plate or sheet called the “beater sheet,”
immediately below the “dead plate.” Now, for reasons to be given, the
position of this plate is important, and in the machine as made by
Messrs. Crighton, its distance from the beater sheet is 2-1/2 inches.
Immediately beyond this point the same firm use an appliance known
as a “leaf extractor,” of which an illustration is given in Fig. 26.
It consists of an endless brattice or canvas band =D=, as wide as
the space between the frames, and having fastened to it transverse
bars of wood =B=. These are shaped as shown, with an edge meeting the
cotton as it moves forward, thus scraping off the leaf, and the space
contained between each pair of these practically forms an air-tight
box for the reception of the leaf. The brattice moves in the direction
of the arrow, and thus meets the cotton as it passes from the beater.
It is kept in tension by means of the rollers =E= =F= and =G=, and as
the bars pass over =E=, which is unattached, its weight causes them
to open, and so drop the leaf into the chamber below. Having thus
described the mechanism of this special arrangement, it is necessary to
say something of the draught regulation and the effect it has upon the
work.
[Illustration: FIG. 26. J.N.]
(78) The regulation of the air current is one of the most important
features in the working of a scutcher. Other things being equal, it is
not too much to say that success or failure largely depends upon it. On
the one hand, it is necessary to provide sufficient suction to draw the
cotton forward and lay it evenly on the cages; on the other, an excess
of suction is very detrimental, as, if the movement of the cotton is
too rapid it will be drawn over the dirt grids _before_ instead of
_after_ the dirt and leaf has fallen. More especially for the sake of
the removal of leaf does the current require to be slow. With any other
procedure the lighter matter cannot fall, and is carried forward to
the cages. An excess of suction further results in the cotton fibres
being drawn into the interstices of the cage surface, and the fleece
does not in that case leave the latter easily. This results in a rough
surface of the lap, and leads when it is rolled up to “licking,” or
adhesion of the different layers.
(79) It is therefore desirable to get the draught as nearly balanced
as is consistent with the required onward movement of the cotton.
What is wanted is rather a large volume of air moving at a slow pace
than a smaller one travelling more quickly. The fan should therefore
be as large as can be conveniently arranged, and should be run at a
comparatively slow velocity. Its exit orifice must be of ample size,
and no obstruction be presented to the current of air. The latter
is delivered into a passage or conduit running below the floor and
terminating either in the open air or a specially-arranged chimney.
All these passages must be made of ample size, and cases are numerous
in which neglect of this requirement has resulted in the inefficient
working of a machine which otherwise ought to have worked well. The
atmospheric changes render it necessary to watch the regulation of the
current so as to suit them, within limits.
[Illustration: FIG. 27. J.N.
(80) The precise effect of the arrangement of the dead-plate and
beater-sheet referred to in paragraph 77 is to decrease the work thrown
upon the fans. The beater, by reason of its rapid rotation, creates a
sufficient current to carry the cotton on to the grids or extractor, if
the space between the dead-plate and sheet is narrowed as described. If
that be increased the effect of the impulse thus given is diminished
proportionately. When so arranged, the cotton impelled as described
passes gently over the leaf extractor, being aided by the slow current
created by the fans, and thus allows the leaf to fall freely and
without difficulty.
(81) In Fig. 27 a diagrammatic representation of Messrs. Platt Brothers
and Company’s arrangement is given. In this case, also, the dead-plate
is arranged so as to narrow the exit orifice from the beater, with a
similar beneficial effect to that described. The cotton then passes
over the bars of a dirt box =L=, into which the leaf can fall, being
periodically removed.
(82) The feed apparatus used is now almost universally combined with a
regulator which bears the name of its inventor, the late Mr. E. Lord,
of Todmorden, and is commonly known as the “piano feed.” It is one of
the most effective motions in the whole range of textile mechanics,
and has considerably increased the regular working of this particular
machine. Referring now to Figs. 28 to 31, which are respectively side,
end, and plan views, it will be seen that the cotton is fed from the
lattice =H= over the nose of the pedal lever =A= and under the feed
roller =B=. After this it is struck by the beater =G= in its rotation.
The shape of the pedal nose varies considerably, according to the
length of the cotton used, the modification in Fig. 28 being that used
for short, and the one in Fig. 29 being employed for long stapled
cotton. The pedal lever is hinged upon a rod, and has behind its
fulcrum a long tail piece which terminates in a hook =I=. On to this
a pendant lever =C= is suspended. The lower portion of each of these
pendants is widened so as to form a double taper surface, as shown in
the end view at =D=. Between each pair of pendants, at its lower end,
small runners or bowls are placed, these being fixed in rods sliding in
the double frame =F=, which at the end =E= is tied together. The last
of the series of pendants =C=^{1} is formed with a slot, as shown, with
which a lever is jointed, as will afterwards be described, and as is
further shown in Fig. 23, which is an end view of the machine shown in
Fig. 22. All the pendants can swing freely upon the pedal levers. The
latter are placed, as shown in the plan, in close proximity to each
other, so as to cover the whole space below the feed roller, while at
the same time they have freedom of movement.
(83) Referring now more particularly to Figs. 22 and 23, the last
pendant lever is coupled by the connecting rod =O= and the levers
shown to the two strap levers =E=, which have sectors formed at one
end gearing with each other. These levers carry the guides for the
strap =N=, which is tightly placed upon the cones =D= =D=^{1}. These
are respectively convex and concave, their outline being a parabola.
The cone =D=^{1} is driven by means of the strap shown from a pulley
on a counter shaft, and revolves at a velocity of 600 revolutions. The
other cone =D= is driven from =D=^{1} by the strap =N=, and is fixed
upon a spindle or shaft which is carried upward (Fig. 23). On the upper
end of the shaft is a worm =P= engaging with a worm wheel =R= on the
feed roller, which is driven by these means, or a change wheel may be
interposed if desired.
(84) The action of this mechanism is as follows. As the cotton is
delivered by the lattice it passes over the nose of the pedal and
between it and the feed roller. If there happens to be a thick piece
in the feed it depresses the nose of the pedal over which it passes.
This raises the pendant rod =C=. Now the space between the thinnest
portion of the pendant foot and the bowls is only sufficient to enable
the pendant to rise a little before pressing on the bowl next it.
Its motion being limited in this way, and the tendency to rise still
occurring, either the pendant must become jammed or the bowl must have
liberty to move to one side. This is what occurs, the lateral movement
of the bowl being permissible to the extent which corresponds to the
space between the remaining pedals and their adjoining bowls. After
this is taken up, pressure exercised by the rising pendant upon the
bowl causes the bar in which the latter is fixed to move in the box to
an extent which is regulated by the depression of the pedal nose. In
other words, the pendant swings on the end of the pedal lever either
to the right or the left as may be required, giving a similar movement
to the rest of the series. The movement thus set up is communicated
to the strap levers =E= by means of the connecting rod =O= and its
attachments, and the strap is accordingly raised or lowered as required
by the circumstances of the case. The weight of the parts connected to
the pedal levers are sufficient to press their noses against the feed
roller unless prevented by means of the cotton being fed. Thus a thin
place in the material at any part of the width of the feed roller is
followed by the reverse action to that named, the strap being moved
on the cones in a similar manner. The presence of a thick place in
the feed decreases the velocity of the driven cone and feed roller,
while the reverse action occurs when a thin place is presented. Thus
the retardation of the cotton in the one case leads to any extra
thickness being rapidly beaten out, more blows being given to the same
length fed than would be under ordinary circumstances. On the other
hand, a thin place results in the quickening of the feed roller and
a greater quantity of cotton is beaten off in the same time. In this
way an evenly-weighted delivery takes place, and this, in conjunction
with the lap feed, of which more will be said hereafter, enables a
lap to be finally produced, in which the variations of thickness are
comparatively slight.
[Illustration: FIGS. 28, 29, 30, AND 31. J.N.]
(85) At one time it was the universal custom to strike the cotton
directly from the pedal nose Fig. 32, a practice which, however the
latter was shaped, had many defects. A much better method is adopted
by Messrs. Platt Brothers and Company, and is shown in Fig. 33, which
illustrates the new practice. It will be seen that, when the beater
strikes the cotton directly from the pedal nose, the fibres will be
bent sharply round an angle. In the case of long-stapled cottons
especially this is detrimental, as it is liable to lead to rupture or
breakage of the fibre. With the shorter-stapled varieties this is not
so likely to occur, and the use of a pedal and feed-roller is more
permissible. The arrangement shown in Fig. 33 is a much better one, and
consists in the employment of an additional pair of feed rollers placed
between the pedal and the path of the beater. There are two distinct
advantages from this procedure. The cotton is bent round a larger
curve when it is struck by the beater, and is, therefore, less liable
to rupture; and the feed-rollers exercise a certain amount of drawing
action. The latter point is of some value. The cotton in passing under
the feed roller and between it and the pedal nose is held by them. The
correction of thick or thin places and the alteration of the speed of
the feed to meet them is controlled from this point. If the second set
of rollers revolves at a slightly quicker speed than the one above the
pedal the cotton will be a little drawn. In any case, this action will
take place to a greater or less extent, and the thick places will thus
be partially thinned out before being struck by the beater. The shock
of the stroke is thus considerably diminished, and the risk of damage
much lessened.
[Illustration: FIGS. 32-34. J.N.]
(86) It only remains to be said with regard to the Lord pedal motion
shown in Figs. 28 to 31 that it is now amended by the introduction of
two bowls between each pair of pendants, which are acted upon singly by
the pendant they adjoin. The latter point is illustrated in Fig. 34,
which represents the old method of arranging the pendants and rollers,
and an improved plan of Messrs. Howard and Bullough. In the former
case each pendant engaged with one side of a bowl, with the other side
of which the adjoining pendant also engaged. In the event of both of
the latter rising at once, it is apparent that the bowl will tend to
be rotated in opposite directions. In effect it becomes practically
inoperative, and the friction set up is considerable, preventing the
easy movement of either pendant. To obviate this, the three-bowl
arrangement shown in Fig. 34 is adopted. The pendants are made with
one flat face, and with one on which a rib is formed. On the spindle
three bowls are placed, the centre one being of smaller diameter than
the others. The two outer bowls engage with the flat side of one of
the pendants, but are entirely out of contact with the adjoining one.
On the other hand, the central bowl engages with the rib formed on one
pendant, but is too small in diameter to engage with the flat face
of the next of the series. Thus the whole of the pendants could rise
simultaneously without setting up the friction referred to owing to the
cross torsion on the rollers. The sensitiveness of the motion is thus
largely increased. The adoption of two bowls, each independent of and
out of contact with the other, produces a similar result.
[Illustration: FIG. 35. J.N.]
(87) There are several modifications of the pedal motion in use, but,
before passing on, the arrangements used by Messrs. Platt Brothers and
Company may be described. Dealing first with the driving of the cones
reference may be made to Fig. 35. The spindle of the driving cone =B=
is prolonged so as to rest in a footstep and has fixed upon it the
double-grooved pulley =S=. An endless rope or band is passed round the
pulley =I=, which is the driving pulley, and thence passes round the
pulley =G=, carried on a pin, the position of which can be regulated
by the screw shown. After going once over the pulley =G= the band is
conveyed round the upper groove of the pulley =S=, back to =G=, thence
to the carrier pulley shown, again round =S=, and finally returns to
the driving pulley =I=. A little consideration of the course thus
followed will show that there is a pull upon the spindle of the cone
=B= in diametrically opposite directions, and as the pull is in each
case equal, the wear of the shaft and footstep is materially reduced.
The consequence is that high velocities can be attained with the utmost
ease, and without any undue strain upon the ropes or shafts.
(88) Referring now to Fig. 36, which is a front view of the pedal
arrangement, it will be noticed that the levers =P= are each of them
placed between two bowls, which are actuated by their own pendants
only. Instead of coupling the regulating levers to the last of the
series of pendants, a different arrangement is adopted. The hanging
lever =O= is fastened at its upper end on a pin carried by the horn
bracket shown, which is fixed to the bowl box. On the other end of the
pin is a second lever, shorter than =O=, and also fixed to the pin.
Thus any oscillation of the lever =O= is followed by a similar movement
of the second lever. The lever =O= is long enough to enter the bowl
box, and any lateral movement of the bowls causes a similar movement
in the lever. This is repeated by the shorter lever, which is coupled
to a connecting rod =Q=. The latter is made in two parts, connected
by a nut, with a right and left handed thread, so as to permit of
any adjustment necessary, which is also aided by the slots shown as
existing in the various levers in the series. The rod =Q= is jointed to
an =L= lever =R=, on the horizontal limb of which the balance weight
=T= is fastened by means of a pin passing through the slot. To the
extremity of this limb of the lever =R= a chain =F= is coupled, which,
passing over a grooved pulley placed above the cone box, is attached to
each of the strap levers =O P= (Fig. 35). These levers are hinged in
the manner shown, and carry strap forks acting upon the strap =C=. The
relative positions of the strap and levers, at a point midway of the
length of the cones, are shown by the dotted lines in Fig. 35. On the
spindle of the cone =A= is the worm =L=, by which the feed rollers are
driven, the three roller arrangement being in this case used, one of
them revolving above the nose of the pedal lever.
[Illustration: FIG. 36. J.N.]
(89) The action of this mechanism is easily explained. As the pedals
are depressed or elevated the bowls are moved laterally, as previously
described. The last of the series being in contact with the lever =O=
causes it to oscillate, and, in consequence, the shorter lever jointed
to the rod =Q= is moved. This motion is communicated to the chain
=F=, which exerts a pull upon the strap guides, and raises or allows
them to fall as described. One cardinal feature in this arrangement
is the power of adjustment which is given at every point, the balance
weight =T= being easily set to give the exact amount of pressure of
the lever =O= upon the last bowl, while at the same time permitting
it to oscillate without an excessive power being required. This makes
the motion very sensitive, which is assisted by the size of the cones,
and by placing the pedals on knife-edged supports instead of a shaft.
Usually the cones are made about 4 inches diameter at the large end and
2-1/2 inches at the smaller. In the machine, as made by Messrs. Platt,
the cones are 8 and 5 inches diameter respectively at each end, and,
as their velocity is high, a slight pull upon the strap vertically is
sufficient to move it up or down the cones.
(90) A special arrangement, made by Messrs. Dobson and Barlow, is
shown in Figs. 37 and 38 in elevation and plan. Here the pedals =W=
=W=^{1} are all of the same shape, and the last of the series =W= is
not coupled to a connecting rod, as shown in Fig. 22. Instead of this,
three bowls, =R R T=, are placed upon a pin which passes through the
forked end of the small frame =Z=. The rollers =R R= roll in the groove
in the box, and are provided with broad flanges which keep them in
position laterally. The roller =T= is in contact with one edge of the
last pendant =W=, and when the latter is pushed to one side it presses
upon the roller and causes it and the cradle =Z= to move in the same
direction. A pin in the other end of the cradle passes through the end
of a lever =Y=, which fits between the fork in =Z= and passes through
a hole in the cross-piece of the bowl-box. The thrust upon the rod =Y=
is therefore given in the centre of the pendants, and these are not
liable to be twisted. The rod =Y= is jointed to the =L= lever shown,
which forms part of the series connecting the pedals and strap guide
levers. As shown in the detached sectional view, Messrs. Dobson and
Barlow employ between each pair of pendants three anti-friction bowls,
=U V U=, which work loosely upon the pin =X=. The latter is made in the
centre with a boss, eccentric to its main portion, and in this way the
central bowl =V= is caused to engage with the pendant =W=, while the
other two =U= engage only with the pendant =W=^{1}. The pin =X= cannot
revolve by reason of being fitted into a square hole in one of the
bowls sliding in the groove in the box, so that the relative positions
of =U= and =V= are always maintained.
(91) In Figs. 39 and 40 a front and side elevation of the pedal
regulator as made by Messrs. Asa Lees and Co. Limited, is illustrated.
The pedals =E= are hinged at one end, and rest upon vertical rods =J=,
the lower ends of which press on the extremities of the balanced plates
=B=. Each of these is suspended on a larger plate =C=, of similar
construction, which in turn rests on the extremity of a plate =D=. The
latter is suspended by its centre from a lever, =F=, which is fulcrumed
on a knife edge at =H=. The lever =F= is coupled in the manner shown to
the strap guide lever =I=, which is moved by means of the horizontal
bar shown, which slides upon guide runners. The cones =A= =A=^{1}, are
placed horizontally, the advantage claimed for this position being that
the strap has a much easier motion along the cones than is the case
when the latter are vertical. It will be observed that the whole of the
balanced plates are in equilibrium, and are suspended on the end of the
lever =F=. Thus a slight movement of one of the smaller plates, =B=, is
multiplied before it acts upon the lever =F=, and the regulation of the
strap is thus rendered more sensitive.
(92) In Fig. 41 a side elevation of the driving gear used by Messrs.
Asa Lees and Co. is shown. In this case the whole of the essential
movements are driven by means of one endless rope. This plan obviates
the difficulties which arise if a beater strap breaks and the feed
continues, or if the delivery ceases from the same cause and under
the same circumstances. In this case the lap attachment and cages are
driven from the pulley =D=, the beater and the cones also by the same
rope. The direction of the rope’s movement is indicated by the arrows,
and a tightening screw is provided to keep the band in tension. On the
shaft of the beater is a friction clutch, one-half of which is formed
into a grooved pulley. By disconnecting the clutch, the beater can be
stopped independently of the rest of the machine.
[Illustration: FIG. 41. J.N.]
[Illustration: FIGS. 37 AND 38. J.N.]
[Illustration: FIG. 39.]
[Illustration: FIG. 40. J.N.]
[Illustration: FIG. 42. J.N.]
[Illustration: FIG. 43. J.N.]
(93) Having thus described the principal methods of arranging the
mechanism adopted by various machinists, there are one or two words to
be said with reference to combined machines. These are very numerous
and various, being arranged in several ways to suit the requirements
of particular spinners. For instance, in Fig. 9, described in the last
chapter, there is a combined machine, viz., an opener and lapper. The
machine shown in Fig. 20 is an instance of a combined opener, scutcher,
and lap machine. So, again, the machines shown in Figs. 13 and 14 are
similar combinations, and in Fig. 8 is an example of a breaker feed
combined with an opening cylinder—in different rooms but coupled by an
air pipe—used as an aid in forming a stack of mixed cotton partially
cleaned. In Fig. 13 a representation of the arrangement of a scutching
room with a mixing room above it is given in section, and in Fig. 42 a
plan of the mixing lattices. In this the bale breaker =A= delivers the
cotton to a double ascending lattice =B= by which it is transferred to
the series of longitudinal aprons =C=. Openings are placed above each
bin =E= so that the cotton can be discharged into any of them at will.
Alongside the mixing bins is a longitudinal lattice =F=, on to which
the cotton is placed as it is taken from the stacks, and is carried
to the porcupine feed table =G=. Immediately after being treated by
that machine the material passes into the dust trunks =D=, over the
dirt grids at =K=, to the cylinder of the opener =H=. The laps there
formed are placed in the scutcher =L=, and those made in that machine
are fed to =M=. The laps formed on the opener are fed to the scutchers,
as shown in Fig. 22. In Fig. 43 a plan is given of one arrangement of
a scutching room, showing a complete set of machines for dealing with
Indian or other dirty cotton. For long stapled clean cotton, such as
Egyptian, only the two machines enclosed within the dotted lines are
necessary. Most of the figures dealing with these combinations are
representations of actual arrangements carried out by Messrs. Platt
Brothers. It is obvious that some plan must be adopted by which the
supply of cotton must be stopped when the scutching machine is knocked
off. If this was not the case, the air tubes and dust trunks would
speedily become full, and there would be the risk of a breakdown when
the machine was re-started. In view of this difficulty, Messrs. Platt
arranged that when the machine is being stopped, the porcupine feed
roller is stopped so much before the opener cylinder that the whole of
the cotton delivered by it is drawn out of the dust trunks. Conversely,
when the machine is being re-started, the feed mechanism is the first
to begin operations, so as to ensure an ample supply of cotton to the
cylinder, and thus avoid any thin places or failure in the resultant
lap. This is a matter of some importance, as upon it depends very
largely the regularity of the laps.
(94) It is of extreme importance to produce laps at an early stage,
as they play a great part in effective spinning. Before dealing with
this point a few words may be said about the necessity for care in
feeding the cotton. The fibre is easily ruptured, more especially
at the points, which, owing to their distance from the seed during
growth, are often solid. It is conceivable that the cotton might
be fed at precisely the same speed as that of the periphery of the
beater blades. In that case it would simply pass through the machine
without any treatment whatsoever. Or it might be fed so rapidly that
the beater in its rotation would knock it off the end of the lap in
tufts or lumps. As the blow of the beater is given transversely of the
fibre, such a treatment would produce a large amount of broken fibre.
It is, therefore, of importance to feed so that the cotton is neither
broken by overfeeding or pulverised by underfeeding, and in fixing the
right velocity the length of the fibre requires carefully taking into
account. The conditions of successful and economical work are well
known, and may be stated as follows: The blow given must be sharp,
and not dragging; the beater blades must be shaped to detach, without
rupturing, the fibres; the rate of the feed roller must be regulated
to insure the thorough detachment of the material; and, finally, the
cotton should not be struck from a sharply angular surface. It is,
of course, impossible so long as revolving beaters are used to avoid
bending the fibres, but it is quite possible to so shape the surface
from which they are struck as to minimise the risk of damage.
(95) The various illustrations given of both opening and scutching
machines show that it is the practice to form the cotton at as early a
stage as possible into a lap. Not only is this course more convenient,
but it is decidedly preferable where good work is required. In cases
where it is the custom to eject the cotton from the opener in its
opened condition, it is necessary to lay it on the feed lattice of
the scutcher, either manually or by means of a lattice. A practice
which is now almost obsolete is to weigh the cotton by means of
scales adjoining the feed apron, and spread it on the latter by hand.
Even with expert attendants, the risk of uneven feeding by this
plan is great, and uneven feeding means unevenly-weighted laps as a
result. By the exercise of a little care, and more especially if the
piano-feed be fitted to the opener, a lap it produced on that machine
the inequalities of which are much reduced. The author recently saw
a lap, paragraph 52, produced on the combined feed, opener, and
scutcher of Messrs. Platt, which was the first made on the particular
machine employed, and which was remarkably regular in thickness. The
same result has been seen in other cases, and by obtaining a regular
sheet at this early stage many advantages arise. Whether an opener be
employed in conjunction with a breaker scutcher or not, the formation
of a lap is a great help to good work. Where such a combination exists,
it is customary to fit pedal regulators immediately before the scutcher
beater is reached, so that the inequalities existing in the sheet
as it is taken from the first pair of cages are at once corrected.
A reference to Figs. 10 and 20 will show this application fitted
respectively to the opener feed and the scutcher beater.
(96) Whatever may be the practice with regard to the opener, the
breaker scutching machine is invariably provided with the lap
attachment, and the finisher scutcher is fed from laps. A reference to
Fig. 22 will show that the machine is fed from three laps =F=, which
are laid upon the travelling lattice apron =G=. The forward movement of
this lattice unrolls the laps and delivers them to the feed rollers,
they being prevented from moving forward by the rods through their
centres, which press against the vertical projections on the lattice
frame. It is often customary to use four laps instead of three,
especially in passing them through the last machine.
(97) It will be apparent on reflection that the laps as produced will
vary considerably in weight and substance. When first formed, and
taken from the machine, each lap is weighed, and a record kept of its
weight. In selecting the laps from which the finisher scutcher is to be
fed, regard is paid to these variations. If one or two laps are under
weight to a certain extent, while others are over it to a corresponding
amount, the machine is supplied with both. As they are all fed at the
same time, it follows that to a large extent the irregularity existing
in one is corrected by the converse irregularity of another. This is,
of course, a matter of degree, but roughly speaking, the correction is
an effective one. By this system of doubling, as it is called, and by
the regulation afforded by the pedal motion, the lap produced finally
has rarely more variation than 5 per cent., and in many cases the
variation does not exceed 1-1/2 per cent.
(98) There must be with a machine fed from four laps, as there is even
in the opener, a considerable amount of draught existing, for it is
obvious that the resultant lap will be no heavier than one of those
fed, and is in most cases lighter. That is to say, the lap is elongated
so that an equal length of the finished lap weighs less than that of
those fed. Thus the irregularities of thickness existing in any of the
laps fed to the machine are diminished by the draught of the machine,
and when this factor is combined with that arising from the treatment
of four laps together, the result is found in the regularity stated. It
is desirable to get as many doublings as possible, and where very good
work is required the material is passed through three machines before
the final laps are produced. This part of the subject is so easily
understood that it is not necessary to further treat it.
(99) A point which is almost as important is the necessity for getting
even selvedges to the laps when produced. The lap referred to in
paragraph 52 had this feature, and there can be little doubt that the
regulation of the air current plays an important part in this respect.
It is of the highest importance that no thin places shall be found
in the selvedges, as their effect is afterwards seen through every
succeeding stage in spinning. Messrs. Platt Brothers have adopted a
construction of their various machines, by which a gradually decreasing
width is found in each of the series. Thus, if the opener produces a
lap 48 inches wide, it will be fed to a scutcher 47 inches wide only,
the lap so produced being that width. A similar or greater reduction
is effected in the last of the series, the width being correspondingly
reduced. In this way a very even selvedge is produced, with the
consequent advantages.
(100) The weight of a lap is determined by weighing one or two yards.
If it be afterwards desired to see what “hank” the lap is, the weight
of the piece is obtained, and the weight of a pound calculated from
it. That is divided into a constant number, obtained as afterwards
described, and the resulting decimal gives the hank lap.
(101) The draught in a scutching machine takes place at the following
points: 1st, between the feed lattice and rollers; 2nd, between the
feed and the lap rollers.
(102) It only remains to be said that by the employment of air trunks
and combined machines the finished laps can be produced by the aid of
only two or three workpeople. The cotton requires no handling from the
mixing room till the first lap is produced, and only then requires
weighing and placing upon the finisher scutcher lattice table.