IMPROVEMENTS IN ORNAMENTING PAPER, WOVEN FABRICS, AND OTHER SURFACES, AND IN APPA- RATUS EMPLOYED THEREIN.
Year: 1870

page_text: LETTERS PATENT to Hubert Airy, of Flamsteed House, Greenwich,
in the County of Kent, for the Invention of "IMPROVEMENTS IN
ORNAMENTING PAPER, WOVEN FABRICS, AND OTHER SURFACES, AND IN APPA-
RATUS EMPLOYED THEREIN.
"D
Sealed the 15th September 1870, and dated the 1st July 1870.
PROVISIONAL SPECIFICATION left by the said Hubert Airy at the
Office of the Commissioners of Patents, with his Petition, on the
1st July 1870.
I, HUBERT AIRY, of Flamsteed House, Greenwich, in the County of
Kent, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN ORNAMENTING PAPER, WOVEN FABRICS, AND OTHER SURFACES, AND IN
APPARATUS EMPLOYED THEREIN," to be as follows: :-
ر"
This Invention has for its object improvements in ornamenting paper,
woven fabrics, and other surfaces, and in apparatus employed therein.
I suspend a heavy weight with a tubular glass pen attached to it by two
cords or bands or pairs of bands from two fixed points at some distance
apart; usually I take two hooks in the ceiling of a room. The two
cords or bands can be nipped together at any height by a sliding clamp. ·

page_text: I take some kind of ink into the pen by suction. By means of all this
I draw curves on a sheet of paper suspended below in contact with the
pen point by india-rubber bands attached to the four corners of the
paper from a frame which rests on the floor; I pull the weight to one
side from its position of rest and then let go and leave it to swing free,
and the pen traces its path on the paper. The weight is heavy enough
to overcome the slight friction of the pen on the paper, and the curve
described on the paper exactly represents the curve described by the
weight as it swings in the air. By altering the position of the sliding
clamp the curve is altered, and at certain positions (when the period of
oscillation of the weight to and fro bears some definite ratio to the period
of oscillation crosswise) the curve described is remarkably regular and
beautiful.
By using lithographic ink on transfer paper I can adapt these figures
for lithography. For this purpose I take lithographic ink into my
tubular glass pen (drawing it up gently by suction) and stretch a sheet
of lithographers' transfer paper by india-rubber bands at the four corners
in the frame which rests on the floor beneath the pen, then lowering the
pen or raising the frame till the pen can touch the paper, and pressing
the paper down with one hand while I start the pendulum with the
other, or by some other method, I am able to let pen and paper come
into contact without blotting, and the pen continues to trace its appointed
curve on the paper till I think fit to break the contact by depressing
the paper and checking the pendulum. The drawing thus made with
lithographic ink on transfer paper is transferred to lithographic stone by
pressure, and then by the ordinary process of lithography any number
of copies can be printed from the stone which has thus received the
drawing.
I also imitate these natural figures by machinery which enables me
to engrave them on copper plate or copper rollers or any other metal for
engraving, and thus I apply them to the ornamentation of cambric and
other fabrics.
I arrange machinery for this purpose in the following manner :-)
-For
engraving on a roller I furnish the roller with a central pivot at each
end, and lay it in horizontal bearings so that it can rotate about its axis,
or I fix the roller in a frame so furnished, and I give a movement of
oscillation to the roller or to this frame by a rod at right angles to the
axis of the roller connected with an eccentric adjustable pin in one face

page_text: of the roller or of the frame, and connected at the other end with an
adjustable crank pin that slides in a radial groove in the face plate of a
spindle that lies parallel to the axis of the roller worked by steam or
other power. When the crank pin is fixed, if the crank rod is of proper
length, the movement given to the roller exactly imitates the to-and-fro
oscillation of a simple pendulum without friction, and by a screw
depending for its motion on the revolution of the spindle the crank pin
may be made to slide slowly in the radial groove towards the centre in
such a manner as to imitate exactly the effect of friction in retarding
the swing of a pendulum. Above the roller I arrange a graving tool
that slides in a fixed horizontal groove parallel to the axis of the roller,
and by a rod connected with an adjustable crank pin on the face plate
of a second spindle, either at right angles to the first or parallel with it,
I give to the graving tool a movement of oscillation exactly imitating
that of a pendulum. Thus I obtain exactly the same conditions that
I have in my compound pendulum in which there are in fact two
systems of oscillation in two planes at right angles, and the figure traced
on paper by the pendulum pen is exactly imitated by the figure graved
on the roller by the graving tool. The second spindle is connected with
the first by toothed wheels, and by varying the number of teeth in the
various wheels I can obtain any desired ratio between the periods of
oscillation of roller and graving tool just as in the compound pendulum
I obtain the same result by means of the sliding clamp. If I place the
second spindle at right angles to the first I connect them by bevelled
gearing; if I place the two spindles parallel I use a right angled lever
or other gear to change the direction of the rod that drives the graving
tool.
By changing the driving gear I change the oscillatory movement of
the roller into uniform rotation, and thus the pattern engraved on the
roller becomes continuous all round the roller.
By using two or more graving tools simultaneously all sliding together
I get two or more patterns intertwined.
For engraving on a plate I fix the plate on a sliding frame which is
moved by gearing similar to that which drives the gearing tool. The
two motions are at right angles and exactly imitate the motion of the
compound pendulum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Hubert Airy in the Great Seal Patent Office on
the 31st December 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUBERT
AIRY, of Flamsteed House, Greenwich, in the County of Kent, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of July, in the year of
our Lord One thousand eight hundred and seventy, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Hubert Airy, Her special license that I,
the said Hubert Airy, my executors, administrators, and assigns, or
such others as I, the said Hubert Airy, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN ORNAMENTING PAPER,
WOVEN FABRICS, AND OTHER SURFACES, AND IN APPARATUS EMPLOYED THEREIN,"
upon the condition (amongst others) that I, the said Hubert Airy, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Hubert Airy, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its object the production for ornamental
purposes (for the ornamentation of paper, calico, cambric, pottery, or
other surfaces) of an extensive series of geometrical figures or patterns
formed by the combination of two motions at right angles, or at any
other definite angle when some definite mathematical proportion holds
between the periods of those motions.
This chient is cained in various ways.

page_text: First, by the swinging of a compound pendulum whereby a great
variety of separate figures is drawn in ink of any kind, or in pencil
on paper of any kind, or on wood or by a pointed instrument on steel
or copper plate, coated with protecting matter for etching, whereby
also these figures are traced by a pointed instrument on the surface of a
copper cylinder coated with protecting matter.
Second, by a machine which closely imitates the natural figures drawn
by the pendulum and also executes a great variety of kindred figures
all coming under the definition given above. The machine is made to
trace or engrave these figures on the surface of a copper cylinder, such
as is used by cotton printers and others or on the surface of copper plate
or other soft metal.
These methods I will now describe more fully, reference being had to
the accompanying Drawings.
First. The compound pendulum (see Figures 1 to 8).
Figure 1 shews a front view of the compound pendulum and the
adjustable table below it; Figure 2, a side view of the same; Figure 3,
a plan of the adjustable table; Figure 4, a plan of sliding clamp c;
Figure 5, a vertical section of penholder and pen; Figure 6, a plan of
apparatus by which the compound pendulum is made to trace its curves
on the surface of a cylinder; Figure 7, a side view of the same shewing
part of the compound pendulum; and Figure 8, an end view of the
same.
In Figures 1, 2, a, a, are the two fixed points of suspension, two
strong hooks in a horizontal beam, from which hang the two pairs of
bands b, b, of hemp or linen, or other tough material attached below
to the cross bar y on the shaft ; which carries the heavy weight d; c
is a sliding clamp by which the two pairs of bands 6, 6, are nipped
together at any desired height. The two halves of the clamp c are
slotted (see Figure 4) to slide on the stiff rod f, which is fixed in the
top of the shaft j to prevent any twisting of the bands below the clamp.
The portion of the shaftj below the weight d is screw cut to receive
the heavy nut e, which is used as a subsidiary weight for fine adjust-
ment. The lower end of the shaft j is bored to serve as a penholder,
and carries the tubular glass pen g which is fixed by the side screw q;
h is the paper hanging by four pairs of elastic bands, one pair at each
corner, from the sliders i, i, on eight vertical rods carried by a tray
which rests on a horizontal table k. This table may be raised or

page_text: lowered by the action of the pinion n working in a rack on the pillar 7,
which carries the table and slides in a deep strong socket m. The
table is fixed at any required height by the side screw p. 0, 0, are
milled wheels on the same axle with the pinion n to be worked by hand
(see Figure 3). In Figure 5 the glass pen g is represented as free to
slide in a second tube of glass, which is held by the side screw q.
This is required when the paper or other surface is laid flat and cannot
yield under the pen; j is the screw cut shaft carrying the heavy nut e.
h
I will now proceed to describe more fully the action of the compound
pendulum apparatus. The heavy weight d (of lead or other ponderous
substance) is suspended by two cords or bands or pairs of bands b, b,
from two fixed points a, a, a few feet apart. These bands or pairs of
bands are, as above stated, made to pass through a sliding clamp c, by
which they can be nipped together at any required height. The heavy
weight carries a penholder j, in which is fixed the tubular glass pen g
charged with ink by suction or otherwise, or other suitable instrument,
for purposes hereafter to be mentioned. Beneath the pen is stretched
a sheet of paper by elastic bands attached to the corners of the paper
and to four or more supports i, in a frame that rests on the floor or
on a table k, that can be raised or lowered at pleasure by rack and
pinion or other apparatus. When the paper is raised or the pen
lowered till pen and paper are in contact the oscillation of the heavy
weight, when set swinging, causes the pen to trace a figure on the
paper. The weight is heavy enough to overcome the slight friction
between pen and paper, and the figure described by the pen upon. the
paper exactly represents the figure described by the weight as it swings
in the air. If the weight be set swinging exactly to and fro, backwards
and forwards, across the vertical plane, in which lie the two fixed points
of suspension, it will continue to swing to and fro without deviation
and will swing entirely from the two fixed points of suspension without
any hingeing at the point where the bands are nipped together; but
if set swinging in the vertical plane of suspension (at right angles to
the to-and-fro direction) the swing will continue without deviation as
before, but will hinge entirely from the point where the bands are
nipped together by the sliding clamp, and there will be no motion at
all above that point. Thus we have a long pendulum with a slow
period in one plane, and a short pendulum with a quick period in the
plane at right angles, and these two are combined in one, and when

page_text: .
the weight is set swinging obliquely each of these two component
pendulums asserts its own period of oscillation, and the curve described
by the weight is the result of their combined requirements. By altering
the position of the sliding clamp the curve described by the swinging
weight is altered, and, at certain positions where the period of oscillation
of the weight to and fro bears some definite numerical ratio to the
period of oscillation crosswise, the curve described is one of great
regularity and clegance (see the accompanying specimens shewn at
Figures A, B, and C). The two systems of oscillation consent in the
periodical repetition of the same figure, gradually lessening in both
dimensions as the swing of the pendulum contracts under friction, and
therefore striking its curves in succession, the new within the old, at
regular intervals till the pattern is filled in to the centre where the
weight comes to rest. If I lower the paper before the pattern is filled
in the central portion remains incomplete. The weight in the act of
oscillating descends to its lowest point in crossing the centre of the
figure and rises a little at the margins, so it is necessary that the paper
should be ready to sink under the descent of the pen and rise again
when the pen rises, supposing the pen to be fixed in the holder, but if
the paper is fixed so that it cannot yield then the pen must be ready
to accommodate itself to the change of level. When the pen is fixed
in the holder the paper must be hung by clastic suspension; for this
purpose I employ a pair of india-rubber bands (at right angles) at each
corner of the paper. Each pair of bands is furnished with a hook or
other instrument to hold the corner of the paper, and each band is
attached at the other end to a slider on a separate vertical rod; by the
aid of these sliders the level of the paper can be nicely adjusted under
the pen.
Then lowering the pen to the level of the paper, but
depressing the paper at the same time by hand, I pull the pendulum
from its central position and start it with such dimensions of swing as
I think fit, and let the paper rise to meet the pen at any moment that
I please, or, having started the pendulum, I raise the paper to meet the
pen by the rack and pinion or other apparatus. If my paper is stretched
on a flat unyielding surface, or if the design is to be drawn on wood or
other unyielding material, I make my pen capable of sliding easily in
the penholder, then the paper is pressed only by the weight of the pen
at the margins of the figure; the pen slides a little way down in the
penholder and slides up again in crossing the centre.

page_text: For the mechanical raising and lowering of the paper (Figures 1, 2, 3,)
I place the paper carrier on a flat table k which is supported by the
pillar of square section which slides in the strong socket m, and is
actuated by rack and pinion n with a clamp screw p in one face of the
socket to fix the sliding pillar at the desired height, or I use some other
mode of raising and lowering the paper to suit the requirements of any
particular case. I provide against twisting in the bands below the
sliding clamp by fixing a stiff rod ƒ of wood or metal of square section
in the weight rising through a slot in the slider where it fits close. For
fine adjustment of the proportion between the two periods of oscillation
I use a heavy nut e working on a screw thread on the penholder below
the weight or above it. A change in the position of this nut causes
a very slight change in the position of the centre of gravity of the
pendulum, and therefore causes a very slight change in the proportion
between the two periods of oscillation.
For the production of symmetrical figures I take the two points of
suspension on the same horizontal line. By taking the two points at
different levels I produce a series of figures somewhat distorted.
I apply the above process to lithographic purposes by using litho-
graphic ink and lithographers' transfer paper. The figure produced is
then transferred from the paper to a lithographic stone, from which
copies can be printed in the ordinary way on paper or parchment or
other surface, or figures or patterns may be drawn directly upon the
lithographic stone or plate.
I etch these curves on steel or copper or other plate by placing the
plate coated with protecting matter under the pendulum, in the pen-
holder I place a sliding pointed instrument, and I increase the weight
so as to overcome sufficiently the friction of the instrument on the
metal; the pattern is traced through the coating of wax by the point
of instrument, and when the acid is applied the metal is eaten into
along the lines thus traced, while elsewhere it is protected by the wax;
the plate is then used for printing. The compound pendulum apparatus
may also be caused to trace its curves on the surface of a copper
cylinder coated with wax or other protecting matter by means of the
apparatus shewn in Figures 6, 7, 8. The tool x is carried by the
frame which slides on the parallel bars u, u. These parallel bars are
connected at their ends by triangular pieces which pivot (t, t,) on the
0

page_text: opposite centres of the mandril that carries the cylinder r. To the
sliding frame is connected by a universal joint the rod w which
slides in the axis of the pendulum. It will be seen that if the weight d
be made sufficiently heavy the oscillations of the pendulum will be
obeyed by the frame which carries the graver x in contact with the
surface of the cylinder.
I also produce these same pendulum curves and others akin to them
in a form suited for printing on paper, muslin, or other woven fabrics
by a machine which engraves any of this series of figures on the
surface of a copper cylinder such as is commonly used by cotton
printers and others, or on copper plate: This I effect by giving an
oscillating to-and-fro motion to the cylinder or plate, and an oscillating
to-and-fro motion to the tool, and by gradually increasing or decreasing
the range of oscillation of the cylinder or plate, and of the length of
the tool's stroke, so as to imitate the result of friction upon the com-
pound pendulum.
The arrangements of machinery I adopt for giving these motions to
the cylinder or plate and to the tool are shewn at Figures 9 to 21 of
the Drawings annexed.
The different forms of machine are represented in the accompanying
Drawings (Figures 9 to 21).
Figure 9 shows a general plan of engraving machine; Figure 10, a
right elevation of same shewing counterpoises w, w; Figure 11 shows a
back elevation of part of same; Figure 12, left elevation of part of same;
Figure 13, front elevation of same; Figure 14 shews apparatus for
engraving on revolving plate; Figure 15, apparatus for engraving on
sliding plate; Figure 16, section through long nut and screw in traveller;
Figure 17, section through travelling crank pin and a cross nut and
screw; Figure 18, section of ratchet gearing through axis of mandril;
Figure 19, front elevation of ditto; Figures 20, 21, winch for turning
screws which carry traveller.
Figures 9, 10, 13 shew an adjustable crank pin on an adjustable crank
plate giving an oscillatory movement.
Figures 14, 18, 19 shew apparatus for giving a movement of successive
onward rotation.
Figure 15 shews apparatus for giving an unequal oscillatory move-

page_text: I fix the cylinder a on an axle or mandril and place it horizontally
with the ends of the mandril resting in V bearings or in round bearings
or otherwise b, b, in the two upright standards which support the
horizontal bed of the slider which carries the tool. One end of the
mandril is in bearing against an adjustable lathe centre c; the other end
carries a collar d in bearing against the face of the bed of the V bearing b,
so that the cylinder is kept from end-shake between the collar and
centre bearing. This end of the mandril projects beyond its bearings
through a large vertical slot in the upright standard far enough to
receive the various pieces of driving gear to be mentioned hereafter.
Above the cylinder and parallel with its axis lies the strong horizontal
bed e, which is slotted to receive the long slider f. The tool is carried
by the box g, which can be clamped at any point along the slider f.
Now if we give a regular to-and-fro motion to the slider which carries
the tool, and at the same time a regular oscillating motion to the cylinder
under the tool, we shall have a figure traced on the surface of the
cylinder by the tool, and the shape of that figure will depend on the
proportion that holds between the rate of the tool's stroke and the rate
of the cylinder's oscillation, and will accurately resemble the corresponding
figure produced by the compound pendulum when the same proportion
holds between its two periods of oscillation to and fro and crosswise.
The stroke of the tool represents one of the component oscillations of
the pendulum as above described, and the motion of the cylinder
represents the other, and the two combined conspire to produce the same
series of curves that were before obtained from the pendulum. If at the
same time we employ means for diminishing the length of the tool's
stroke and diminishing the range of the cylinder's oscillation continuously
we shall obtain an imitation of the gradual lessening of the dimensions
of the curve as produced by the pendulum.
These two main purposes (1) to give proportionate periods to the
motions of tool and cylinder, (2) to effect a gradual diminution in the
range of those motions are served in the following manner :-)
-The tool
and cylinder are driven respectively by the connecting rods ; and k
from the crank pins t, t, carried by the spindles m and n. The inter-
mediate driving spindle is put in gear with the two working spindles
m and n by pairs of toothed wheels o, o, with certain definite numerical
proportions between the numbers of their teeth, and these pairs of
wheels are so arranged according to their proportions as to cause the

page_text: 3
4
two working spindles m, n, to revolve with the desired proportion
between their rates of revolution. The same effect would be produced
more simply by using only the two working spindles m, n, gearing together
by one pair of wheels of the requisite proportion, but the introduction
of the intermediate spindle gives much greater range and variety of
combination with fewer change wheels. (It is sufficient to have thirteen
pairs of change wheels with the following proportions (equal numbers)
b.) This system of spindles is supported
by fixed standards p, p. Power is applied to the driving spindle 7
either by hand at the crank q or by a strap on the drum r. The change
wheels are carried at one end, and at the other each of the working
spindles carries a strong face plate with a travelling crank pin to be
shortly described. The upper of these two spindles m drives the tool by a
jointed connecting rod j and bell crank h, the lower n drives the cylinder
by a connecting rod k working a crank i on the projecting end of the
mandril. Hence the proportion between the rates of motion of tool
and cylinder is determined by the proportionate rates of revolution of
the two working spindles, which depend on the arrangement of the
toothed wheels by which they are in gearing with one another. The
gradual diminution of the range of stroke of tool or cylinder is obtained
by the following apparatus. The face plates at the end of either working
spindle m or n (the apparatus is the same for both) carries a pair of
bosses u, u, at opposite ends of its diameter which give support to a
pair of parallel screws v, v, one right handed the other left. These
two screws carry two long nuts x, x, which carry while they revolve in
the platform in which the crank pin t is based, and are toothed between
their bearings to gear with a central worm on the head of the con-
necting rod. The revolution of the face plate about the unrevolving
head of the connecting rod causes a slow rotation of the two nuts,
one to right the other to the left, so that they slowly travel along
the parallel screws carrying with them the platform of the crank pin,
and gradually altering (diminishing or increasing) the distance of the
crank pin from the centre of the face plate, and therefore gradually
altering the length of stroke of the connecting rod and with it the
range of motion of tool or cylinder.

page_text: embracing the lower part of the crank pin t by a tubular prolongation d
which carries the worm piece 6 by a feather and slot. By a change of
screws and nuts the alteration of the length of stroke can be made quicker
or slower. The parallel screws are held fast by small side screws where
they lie in the bosses. The crank pin may be brought rapidly to the
desired distance from the centre by freeing these parallel screws and
rotating them one to right the other to left by means of the small winch
gearing temporarily in a pair of small cog wheels 2, 2, on the projecting
ends of the parallel screws and then fixing again by the side screws.
The small winch is shewn in Figures 20, 21, it fits into the boss u by a
couple of pins p, p, and carries a pair of cog wheels q, q, which then
gear in with the wheels z, z. By turning the handler the wheels z, z,
and the screws v, v, with them are made to rotate in opposite directions
and the traverse is drawn forwards or driven backwards as desired.
The closest imitation of the natural pendulum curves is obtained when
both these travellers are in operation, but figures akin to them are
produced by putting only one traveller in operation. This is simply
done by removing the worm piece from the head of that connecting rod
which is intended to retain its original length of stroke, or both travellers
may be put out of operation when it is only desired to produce a simple
outline or skeleton figure. These travellers disturb the balance of the
working spindles, and it is necessary to adapt counterpoises w on either
side which are worked by rack and pinion in the opposite direction to the
movement of the traveller.
I employ various means for transmitting the motion of the connecting
rod to the mandril which carries the cylinder. The simplest of these is
a common crank with adjustable crank pin, provided the distance of the
crank pin from the centre of the mandril be greater than the distance
of the crank pin at the other end of the connecting rod from the centre
of the working spindle. But the crank pin is required to be adjustable
angularly as well as radially, and for this purpose a graduated circular
face plate is fixed on the projecting end of the mandril, and the crank
pin is made adjustable in a radial groove in a crank plate which can
revolve about the centre, and can be clamped in any desired position to
the face plate (Figures 9, 10, 13).
A greater range of oscillation is obtained by using another piece of
apparatus. The connecting rod is prolonged so as to ride in a furrow
between flanges on the top of an adjustable disc clamped to a circular

page_text: face plate which is fixed on the mandril.
The connecting rod is
attached to the rim of the disc by a pair of steel bands or chains crossing.
This arrangement admits of oscillation through more than one hundred
and eighty degrees, which is not possible with a crank. (This simple
piece of apparatus is not shewn in the Drawings.).
By forking the connecting rod, as shewn at Figures 18 and 19, and
attaching the two branches of the fork, one above and the other below,
by two pairs of steel bands or chains to two side discs, which are free
to revolve about the mandril on either side of a ratchet wheel which is
fixed to the mandril, and the discs overlapping the teeth of the ratchet
wheel halfway from opposite sides, and carrying pawl bits gearing in
those teeth, the motion of the cylinder becomes by these means one
of successive onward rotation by successive steps, and if these steps are
aliquot parts of the circumference the pattern is repeated continuously
round the cylinder without break. In this case it is necessary that the
travelling crank pin at the other end of the connecting rod should be
fixed and not allowed to travel when this gearing is used, but the
traveller appropriate to the tool may be left to operate. Other analagous
means for producing the same effect may also be adopted.
In Figures 18, 19, a is the projecting end of the spindle or mandril;
is a strong ratchet wheel (with sixty teeth) embracing the spindle by
projecting sockets, and keyed fast to the spindle; c, d, are a pair of side
discs capable of rotation about the projecting sockets of the ratchet wheel,
and overlapping the tecth of that wheel so as to come in friction contact
over the middle line. Each of these side discs carries a pawl bit or
click e; an oscillatory movement is given to these side discs in opposite
directions alternately by the two bars f, g, which ride between the
flanges of the discs, and are kept parallel to themselves by horizontal
guides o, o. These bars are connected with the side discs by pairs of
steel bands h, h, i, i, the upper bar driving one disc and the lower the
other. The two clicks relieve each other, one taking up the stroke as
the other retires from it, and so the desired motion is obtained. The
bars f, g, are driven by the connecting rod k.
Instead of an equal oscillatory motion an unequal one with back
strokes shorter than forward stroke may be given to the cylinder by
making the two branches of the connecting rod act (by means of steel
bands and overlapping side discs) on two ratchet wheels of unequal
diameters, one branch acting upon the smaller wheel in the forward

page_text: stroke, and the other branch upon the larger wheel in the back stroke,
provision being made for lifting the click from the larger wheel during
the forward stroke. The teeth of the two wheels are set in opposito
directions. The branches of the connecting rod are both above or both
below, both on the same side of the mandril.
An arrangement such as above described is shewn at Figure 15.
Other means for giving an unequal oscillatory movement to the cylinder
may also be adopted.
A similar arrangement is employed for giving the cylinder a motion
of unequal successive onward rotation, proceeding by successive unequal
steps, alternately long and short. In this case one branch of the
connecting rod is above and the other below, and the teeth of the two
unequal ratchet wheels are set in the same direction, or other means may
be adopted for giving a like motion to the cylinder.
By using only one ratchet wheel, actuated by the unbranched con-
necting rod and revolving disc, the cylinder is left at rest during the
back stroke and the motion is one of intermittent onward rotation, or
a like motion may be given to the cylinder in other ways.
A motion of continuous uniform onward rotation is given to the
cylinder by the aid of a strap and pair of drums, or by chain and wheels,
or by toothed gearing between the lower working spindle and the mandril
of the cylinder, or by other suitable means.
For engraving these geometrical patterns straightforward on flat
copper plate, the plate is fixed on a flat table capable of sliding in a
direction at right angles to the stroke of the tool, and a to-and-fro
motion is given to this table by a mandril actuated by a connecting rod
as above, and carrying two or more discs connected with the under
surface of the sliding table by pairs of steel bands. Such an arrange-
ment is shewn at Figure 15, where a is a horizontal table made to slide
in bearings b, b, by the wheels d, d, which are connected with its
under surface by pairs of steel bands. These wheels are carried by a
spindle taking the place of the cylinder axle (Figure 13) and driven by
connecting rod h and apparatus i, which is drawn as adapted for giving
a movement of unequal oscillation, alternately long and short.
Similar patterns are engraved on flat copper plate in a circular
direction, by fixing the plate on a flat horizontal table capable of
revolving about a central vertical axis, as shown at Figure 14, and

page_text: giving to this table a motion of equal or unequal oscillation, equal or
unequal successive onward rotation, uniform onward rotation, or inter-
mittent onward rotation, by gearing similar to what has been already
described in the case of the cylinder.
In Figure 14, a is a horizontal circular table carrying the plate to be
engraved and capable of rotation about a vertical axis in the strong
socket 6. It is actuated by the horizontal spindle d by means of the
bevilled gearing c. i is the apparatus used for giving the spindle d a
movement of successive onward rotation, shown enlarged in Figuers
18 and 19.
Conical rollers may also be engraved in a similar manner to what has
been described above for the cylinder. The slider that carries the tool
must then work parallel to the upper surface of the cone, and the axis
of the cone must be set obliquely.
In all the above-mentioned cases there may be only one tool or there
may be two or more executing the same pattern simultaneously on
different parts of the roller or plate. The tool or tools may be of any
approved shape, and they may be brought down to their work or lifted
from it by a screw motion ready to the hand, and be fixed at their work
by a simple clamp. They are kept to their work by the pressure of a
spring at the back or otherwise, and they may act without being made
to revolve, or a motion of revolution may be given to them by a cord or
cords passing round a large grooved wheel on the driving spindle or
driven by independent power.
An alternative mode of arranging the driving spindles and face plates
is to lay the three spindles in a plane inclined to the vertical (each
spindle lying horizontally) so as to give more room for a pair of drums
on the middle spindle between the other two, and at the same time
allow the requisite difference of level between the two working spindles,
one of which ought to be at the level of the axle of the cylinder and
the other at the level of the tool carrier. The spindle appropriate to
the tool is in gearing by two bevilled wheels with a secondary spindle at
right angles, and this secondary spindle carries the face plate with its
travelling crank pin. By this arrangement the necessity for a jointed
connecting rod and bell crank lever is done away with, and the spindles
are in a firmer position.
Another mode is to make the two travelling crank pins work in
vertical slots in two strong vertical bars which are otherwise free to