IMPROVEMENTS IN APPARATUS EMPLOYED IN ENLARGING AND REDUCING DRAWINGS AND DESIGNS FOR LITHOGRAPHIC PRINTING AND OTHER PURPOSES
Year: 1878

page_text: LETTERS PATENT to Hector Auguste Dufrené, of No. 10, Rue de la Fidélité,
Paris, and 4, South Street, Finsbury, London, Civil Engineer and Patent
Agent, for the Invention of "IMPROVEMENTS IN APPARATUS EMPLOYED IN
ENLARGING AND REDUCING DRAWINGS AND DESIGNS FOR LITHOGRAPHIC
PRINTING AND OTHER PURPOSES." A communication from Monsieur Auguste
Fougeadoire, of No. 8, Rue des Bons Enfants, Paris, in the Republic of
France
Sealed the 27th May 1879, and dated the 29th November 1878.
PROVISIONAL SPECIFICATION left by the said Hector Auguste Dufrené at
the Office of the Commissioners of Patents on the 29th November 1878.
HECTOR AUGUSTE DUFRENÉ, of No. 10, Rue de la Fidélité, Paris, and 4, South
Street, Finsbury, London, Civil Engineer and Patent Agent. "IMPROVEMENTS IN
APPARATUS EMPLOYED IN ENLARGING AND REDUCING DRAWINGS AND DESIGNS FOR
LITHOGRAPHIC PRINTING AND OTHER PURPOSES." [A communication from Monsieur
Auguste Fougeadoire, of No. 8, Rue des Bons Enfants, Paris, in the Republic of
France.]
The Invention communicated to me consists in the construction of an improved
apparatus for enlarging or reducing the surface of india rubber or other elastic
material on which are Drawings or designs which are to be transferred to stone or
utilized in any other manner.
The apparatus is constructed of an extensible frame, on the sides of which the
edges of the india rubber are fixed by a suitable number of hooks. The bars of the
frame are cylindrical and surrounded with spiral springs stretching or contracting
with the frame, and drawing in their movement the herein before described hooks
ID 837

page_text: so as to insure an uniform tension. Movement is given to the bars of the frame
by means of four screws, each having a right handed thread at one end and a left
handed thread at the other end, so as to draw apart or towards one another, two
and two, the bars of the frame.
Two handles placed on two adjacent sides of the stand of the apparatus connect 5
these screws, two and two, by means of an endless chain, and allow of separately
moving two of the parallel bars, or the two others, or the four at once. A scale
placed on the stand shews the exact measure of the enlargement or reduction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hector Auguste Dufrené in the Great Seal Patent Office on the 29th
May 1879.
HECTOR AUGUSTE DUFRENÉ, of No. 10, Rue de la Fidélité, Paris, aud 4, South
Street, Finsbury, London, Civil Engineer and Patent Agent. "IMPROVEMENTS IN
APPARATUS EMPLOYED IN ENLARGING AND REDUCING DRAWINGS AND DESIGNS FOR
LITHOGRAPHIC PRINTING AND OTHER PUrposes." A communication from Monsieur
Auguste Fougeadoire, of No. 8, Rue des Bons Enfants, Paris, in the Republic of
France.
The Invention communicated to me consists in the construction of an improved
apparatus for enlarging and reducing the surface of india rubber or other elastic
material, on which are drawings or designs which are to be transferred to stone or
utilized in any other manner.
The apparatus is constructed of an extensible frame, on the sides of which the
edges of the india rubber are fixed by a suitable number of hooks. The bars of
the frame are cylindrical and surrounded with spiral springs stretching or con-
tracting with the frame, and drawing in their movement the hereinbefore described
hooks so as to insure an uniform tension. Movement is given to the bars of the
frame by means of four screws, each having a right handed thread at one end and
a left handed thread at the other end, so as to draw apart or towards one another,
two and two, the bars of the frame.
Two handles placed on two adjacent sides of the stand of the apparatus connect
these screws, two and two, by means of an endless chain, and allow of separately
moving two of the parallel bars or the two others, or the four at once. A scale
placed on the stand shews the exact measure of the enlargement or reduction.
But to make the Invention communicated to me better understood I will proceed
to describe the same by reference to the accompanying Drawing which represents
a plan in perspective of the improved apparatus:-A sheet of india rubber P is
placed between four metallic bars A, A, A, A, carried on the flat iron bars x, x, x, x,
and sliding two and two in a parallel direction. Motion is communicated to them
by four double screws E, F, G, H, having alternate right and left handed threads
working in the screw nuts r, s, t, u. These screws are moved by the handles R
and S, also driving the chains L and K, which pass over pinions placed at the end
of the axes of the screws. Divisions marked upon the outer frame indicate the
enlargement or reduction produced at the moment the handle is turned.
The iron frame M, N, O, P, surrounds the apparatus; it receives the ends of the
rotating axes of the screws and the handles, it is mounted on four feet which allow
of raising it above the table on which the apparatus may be placed.
At the four corners of the sheet of india rubber four square headed screws are
provided, as shewn in the Drawing; they serve to produce pressure on the
round bars or rods A, and keep the india rubber at the size to which it has been
brought.
The other four screws C' with round heads adjoining the same pieces serve as
feet to the frame, and allow of raising or lowering at will the sheet of india rubber
to the height of the lithographic stone on which it is wished to place it to transfer
the drawing.
The sheet P of india rubber is hooked to the round rods A by means of a largo
number of hooks m; these hooks hooking at one side on to the edges of the sheet
are placed on the other side between the coils of spiral springs extending from one
corner to the other of the frame A, so that the moving of the corners away from or
towards each other moves the coils away or towards each other, the hooks not being
able to slip or slide because they are passed in the spaces between the coils, no fold
or crease will be produced on the sheet.

page_text: Having thus described the Invention communicated to me what is claimed is,—
Firstly. The general arrangement of the apparatus for enlarging and reducing
drawings and designs transferred or drawn on a sheet of india rubber more or less
stretched for lithographic printing and other purposes, as hereinbefore described,
and represented in the accompanying Drawing.
Secondly. The combination of the screws having right and left handed threads
with the chains moved by the handles for stretching or slackening the shee of
india rubber, as hereinbefore described, and represented in the accompanying
Drawing.
Thirdly. The combination of the locking screws and the screwed feet placed at
the corners of the sheet for moving the sheet of india rubber away from or towards
the stone or table, as hereinbefore described, and represented in the accompanying
Drawing.
Fourthly. The combination of the hooks and the helical springs passed round
the rods of the frame, as herein before described, and represented in the accom-
panying Drawing.
'
In witness whereof, I, the said Hector Auguste Dufrené, have hereto set
my hand and seal, this Twenty-seventh day of May, in the year of our
Lord One thousand eight hundred and seventy-nine.
老
H. A. DUFRENE. (LS.)