IMPROVED APPARATUS FOR ENLARGING AND REDUCING DESIGNS, PRINTS, AND OTHER DELINEATIONS
Year: 1875

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVED APPARATUS FOR ENLARGING AND REDUCING DESIGNS, PRINTS, AND
OTHER DELINEATIONS."-A communication from abroad by Victor
Guérin of Paris France.
Sealed the 13th August 1875, and dated the 26th February 1875.
PROVISIONAL SPECIFICATION left by the said Alexander Melvillo
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 26th February 1875.
.I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVED APPARATUS FOR ENLARGING AND REDUCING
DESIGNS, PRINTS, AND OTHER DELINEATIONS," to be as follows:-
This Invention relates to improved apparatus for reducing or enlarging
drawings, designs for labels, lithographic and typographic prints, and
other delineations.

page_text: The Invention is designed to obviate the objections to other apparatus
of the kind heretofore proposed, being of simple construction, and so
arranged that any print or design may be rapidly reduced or enlarged
without liability of distortion.
The apparatus consists of a circular sheet of india-rubber thickened
around its circumference to form a kind of beaded edge, which is firmly
clamped between two metal rings forming a circular frame. The elastic
sheet is drawn over a fixed disc mounted on the end of a screw pillar
attached to any suitable foot or pedestal. On this screw a nut is caused
to travel up and down by means of a hand wheel or otherwise, said nut
being fitted to turn between collars in a plate, to which is attached the
circular frame in which the elastic sheet is clamped. The whole being
thus arranged to stretch the sheet, the nut is turned so as to draw down
the said frame, whereby the sheet is stretched over the fixed disc above
mentioned. The frame simply rises and falls without turning. It will
be seen that the elastic sheet will be uniformly stretched, inasmuch as
the tension is equally applied at all points of its circumference, thereby
enabling perfectly correct reductions or enlargements of the design,
which is transferred on to the sheet of india-rubber, to be obtained.
It will be understood that instead of a stationary disc or screw the
latter may be made to turn, the nut and frame being stationary; instead
of a screw, a rack or other mechanical equivalent may be employed.
Further, in order that the elastic sheet may be uniformly stretched in
every direction and ensure its being properly applied upon the disc I
force air into the chamber formed beneath the sheet of india-rubber at
an opening provided for the purpose, whereby the elastic sheet is raised
and detached from the stretching disc, so that its free extension or con-
traction is not impeded by its adhesion to the said disc. To reduce the
size of design the sheet is stretched before it is impressed thereon,
while for enlarging the design is transferred before the sheet is
stretched.
The Invention is illustrated, by way of example only, in the accom-
panying Drawings, in which,—
Figure 1 is a front elevation of the apparatus, and Figure 2 a plan of
same showing the elastic disc before it is stretched with the design to
be enlarged thereon; Figure 3 is a vertical section on line 1-2,
Figure 2; Figure 4 is a similar section with the elastic disc distended;

page_text: and Figure 5 is a plan of Figure 4 showing the same design as in
Figure 2, enlarged. The same reference letters apply to all these
Figures.
a, foot or pedestal; b, screw pillar fixed thereon and surmounted by
the stretching disc c; d, nut travelling on b; e, wheel with handles f
for turning nut d; g, plate in which nut d is fitted to turn loosely, as
shown. To this plate is affixed ring h, between which and another
ring i the edge of the elastic sheet j is clamped by the aid of nuts k;
or a circular groove may be made around the plate 9, and the edge of
the elastic sheet be secured either by tying or by an elastic ring. The
central portion of the disc or sheet on which the design is transferred
is made of thin india-rubber, while the outer portion which does not
require to be stretched radially is made of rubber fabric, which will
stretch circularly, but not otherwise. 1, aperture for inflating the
elastic sheet with air. The air for this purpose may also be admitted
through a passago m made in the foot a and the screw b, as shown in
dotted lines in Figure 3.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 14th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of February, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Melville Clark,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great

page_text: Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVED APPARATUS FOR ENLARGING AND REDUCING DESIGNS, PRINTS,
AND OTHER DELINEATIONS," a communication to me from abroad by
Victor Guérin, of Paris, France, upon the condition (amongst others)
that I, the said Alexander Melville Clark, my executors or admi-
nistrators, 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 to 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 Alexander Melville Clark, 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, reference being had to the two accom-
panying Sheets of Drawings, and to the letters and figures marked
thereon (that is to say) :-
This Invention relates to improved apparatus for reducing or enlarging
drawings, designs, labels, lithographic, typographic, and other prints.
The reduction and enlargement of such designs is usually effected by
hand, which is a tedious and expensive process, requiring the aid of
specially skilled labor. An apparatus has however already been devised
for the purpose composed of a thin sheet of india-rubber of square form
bearing the design to be reduced or enlarged. In making a reduction
the elastic sheet is stretched previous to the application of the design,
and when allowed to contract the design is also reduced to a corre-
sponding extent. If on the contrary it is desired to enlarge the design
it is transferred to the elastic sheet before the latter is stretched. The
mechanism employed to distend the india-rubber sheet is however
complicated and the apparatus consequently expensive, which has
hitherto prevented it coming into general use.
Another great disadvantage is that owing to the square form of the
elastic sheet the tension is irregular, being greater near the middle of
the four sides than at the four angles, in consequence of which the
design is distorted, instead of being uniformly acted on at all parts.
The present Invention is designed to obviate these objections, the
apparatus being of simple construction, and so arranged that any print

page_text: or design may be rapidly reduced or enlarged without liability of
distortion.
The apparatus is composed of a circular sheet of india-rubber thickened
around its circumference to form a kind of beaded edge, which is firmly
clamped between two metal rings forming a circular frame. The elastic
sheet is drawn over a fixed disc or circular table mounted on the end of
a screw pillar fixed upon a suitable pedestal. On this screw a nut is
caused to travel up and down by means of a hand wheel or otherwise,
said nut being fitted to turn freely between collars on a plate, to which
is attached the circular frame in which the elastic sheet is clamped, so
that the frame will be caused to move up and down with the nut without
partaking in its rotary motion. The whole being thus arranged to
distend the sheet, the nut is turned so as to draw down the said frame,
and with it the edges of the sheet, whereby it is stretched over the fixed
disc or table above mentioned, the extent to which the sheet is stretched.
being regulated by the distance traversed by the nut upon the screw.
It will be seen that the elastic sheet will be uniformly distended as the
tension is equally applied at all parts of its circumference, and therefore
perfectly correct reductions or enlargements of the design transferred on
to the sheet of india-rubber will be obtained.
'
It will be understood that the disc instead of being fixed may be
movable, the screw only being made to turn, the nut remaining
stationary; instead of a screw, a rack or other mechanical equivalent may
be employed.
The rise and fall of the disc for stretching the elastic sheet may also
be obtained by means of an arrangement of spiral springs, which are
compressed and retained in that position. The design being applied
upon the clastic sheet the springs are then released so as to raise the
disc and distend the india-rubber, whereby the design becomes enlarged.
The action is reversed if the design is to be' reduced.
Further, in order that the elastic sheet may be uniformly stretched in
every direction and to ensure that it bears properly upon the disc I blow
or force air into the chamber formed beneath the sheet of india-rubber
at an opening provided for the purpose, whereby the elastic sheet is
raised and detached from the stretching disc, so that its free extension
or contraction is not impeded by its adhesion to the said disc.

page_text: The Invention is illustrated in the accompanying Drawings, which
show two arrangements of the apparatus, by way of example only.
Figure 1, Sheet 1, is a front elevation of the apparatus, and Figure 2
a plan of same showing the elastic sheet before it is stretched, with the
design to be enlarged thereon; Figure 3 is a vertical section on line 1-2,
Figure 2; Figure 4 is a similar section with the elastic disc distended;
and Figure 5 is a plan of Figure 4 showing the same design as in
Figure 2 enlarged. The same reference letters apply to all these
Figures.
a, foot or pedestal; b, screw pillar fixed thereon and surmounted
by the stretching disc c; d, nut travelling on b; c, wheel with handles f
for turning nut d; g, plate in which nut d is fitted to turn loosely, as
shown. To this plate is affixed ring h, between which and another
ring i the edge of the elastic sheet j is clamped by the aid of nuts k;
or a circular groove may be made around the plate g, and the edge of 1
the elastic sheet be secured either by a ligature or by an elastic ring.
The central portion of the sheet on to which the design is transferred is
made of thin india-rubber, while the outer portion, which does not
require to be stretched radially, is made of rubber-coated fabric, which
will stretch circularly, but not otherwise. 1, aperture for inflating the 2
clastic sheet with air, or a passage m may be made in the foot a and
the screw b, as shown in dotted lines in Figure 3 for the same purpose.
Sheet 2 of the Drawings shows the second arrangement of the
apparatus, which differs from that above described only in certain details,
designed to facilitate the use of the apparatus.
These modifications relate,-
First. To the fixed disc or table, which is encircled by a removable
ring for a purpose herein-after described.
2nd. To the substitution of a valve for the plug shown in the former
arrangement.
And. 3rd. To the employment of two hoons or bands. the one for
2

page_text: UI VO заще допоп що 149
Figures 1 and 2.
Figure 3 shows the elastic sheet unstretched, and Figure 4 shows the
same distended.
Figure 5 shows in cross section the ring detached with the rubber
sheet stretched upon it and retained by the hoop or band above referred
to in readiness to be applied to the lithographic stone.
The same letters of reference indicate the same parts in these five
Figures.
a, foot; b, screw pillar mounted thereon surmounted by the stationary
disc c; d, nut travelling on screw b; e, movable plate, in which nut d
is fitted to turn loosely; f, handles for turning nut d; g, valve for inlet
and exit of air; h, ring encircling the stationary disc; i hoop for
clamping the edges of the elastic sheet to the rim of plate e; h, hoop
for securing the said sheet in its distended condition upon the ring h.
The following is the action of the apparatus:-To enlarge, it is first
necessary to produce the design upon the elastic sheet j, which is then
secured by its edges to the plate e by means of the hoop i. This is done
whilst the plate e is in the raised position, Figure 3, and the nut d is then
turned by handles f to draw down the plate e until the elastic sheet is
sufficiently distended. During the descent of the plate air enters at
valve g, which opens automatically. The elastic sheet ; having been
thus stretched and the design thereon correspondinly enlarged, the
hoop is then applied and tightened up if necessary so as to firmly
retain the elastic sheet upon ring h. The plate e is now raised to release
the edges of the sheet from tension, and enable it to be detached from
the plate by removing hoop i, but before doing this the valve g is raised
to allow the air within to escape. The central part only of the elastic
sheet being now retained by the hoop k upon ring / the latter is removed,
as shown in Figure 5, in order to transfer or apply the enlarged design
in any convenient manner to the stone, which is then prepared for
obtaining prints by the ordinary means employed in lithography. In
order to reduce a drawing or design the action is reversed, that is to
say, the elastic sheet is stretched before the design is applied or traced
thereon, and on releasing the sheet the reduction is effected.

page_text: Having described the nature of the Invention and the manner of per-
forming the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is, an
apparatus substantially as described in which a circular elastic sheet is
employed, the apparatus being adapted to stretch the sheet or allow it.
to contract uniformly at all parts of its surface, whereby a design or
delineation upon such surface may be uniformly enlarged or reduced,
whether means be or be not provided to facilitate the removal of the
elastic sheet for copying or transferring the design so enlarged or reduced
to stone, all as herein-before shown and described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Fourteenth day of August, in
the year of our Lord One thousand eight hundred and seventy-
five.