IMPROVEMENTS IN THE METHOD OF PRODUCING MORE PERMANENT FLATNESS IN THE MANUFACTURE OF CARDBOARD, KNOWN AS DRAWING BOARD AND MOUNTING BOARD
Year: 1877

page_text: LETTERS PATENT to Frederick Turnbull and Samuel Turnbull, of Beaumont
Mills, Leyton, in the County of Essex, Cardboard Manufacturers, for the
Invention of "IMPROVEMENTS IN THE METHOD OF PRODUCING MORE PERMANENT
FLATNESS IN THE MANUFACTURE OF CARDBOARD, KNOWN AS DRAWING BOARD
AND MOUNTING BOARD."
Sealed the 3rd May 1878, and dated the 9th November 1877.
•
PROVISIONAL SPECIFICATION left by the said Frederick Turnbull and
Samuel Turnbull at the Office of the Commissioners of Patents on the 9th
November 1877.
"
FREDERICK TURNBULL and SAMUEL TURNBULL, of Beaumont Mills, Leyton, in
the County of Essex, Cardboard Manufacturers. IMPROVEMENTS IN THE METHOD
OF PRODUCING MORE PERMANENT FLATNESS IN-THE MANUFACTURE OF CARDBOARD,
KNOWN AS DRAWING BOARD AND MOUNTING BOARD."
This Invention relates to a new method of treating cardboard, drawing board, and
mounting board during the operation of drying, and the object is to produce sheets
of cardboard, drawing board, and mounting board, the surface of which shall be
more flat and even, and less liable to become warped or bent than those sheets of
cardboard, drawing board, and mounting board which are dried and finished in the
ordinary way. For this purpose we construct pairs of frames (preferably of gal-
vanised iron) the upper edges of which are milled diagonally. These frames are
made of sizes and shapes corresponding to the sizes and shapes of the sheets of
cardboard, mounting board, and drawing board to be manufactured, and they have
a flange projecting on each side in order that a pair of frames may be firmly secured
one upon the other (the diagonally milled edges face to face) by means of clamps
or other suitable fastenings placed at suitable intervals. In a pair of these frames
of suitable size and shape we secure a sheet of cardboard, drawing board, or
mounting board, and allow it to remain so secured during the operation of
drying.

page_text: The manner of securing a sheet of cardboard, drawing board, or mounting board
is as follows-One of these frames is first placed upon a bench or table with its
diagonally milled edges uppermost, and the opening within this frame is filled in
with any clean and flat substance (by preference with a wooden board) the height
of which shall be as nearly as possible level with the upper part of the diagonally
milled edges of the said frame. Upon this wooden board a sheet of cardboard,
drawing board, or mounting board is so placed that it extends beyond the wooden
board in all directions, and covers the diagonally milled edges of the said frame.
Another frame of similar construction is next placed with its diagonally milled edges
downward upon the sheet of cardboard, but the direction of the milling of the edges
should be opposite to the direction of the milling of the edges of the first-named
frame, that is to say, that the diagonal milling of the one should cross the diagonal
milling of the other diagonally. In this position the pair of frames are secured by
means of the clamps above referred to. The sheet of cardboard being thus firmly
secured between the diagonally milled edges of a pair of frames is effectually pre-
vented from warping while drying, and the result is necessarily the production of
a sheet of cardboard which is flat and even, and which also is less liable to warp or
bend through change of temperature or other fluctuations of the atmosphere than
sheets of the same material which are allowed to warp during the operation of
drying. We use frames with diagonally milled edges because the milling, as above
described, forms a series of channels through which the air circulates freely, and
thus the whole sheet of cardboard is thoroughly dried.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Turnbull and Samuel Turnbull in the Great Seal Patent
Office on the 7th May 1878.
FREDERICK TURNBULL and SAMUEL TURNBULL, of Beaumont Mills, Leyton, in
the County of Essex, Cardboard Manufacturers. "IMPROVEMENTS IN THE METHOD
OF PRODUCING MORE PERMANENT FLATNESS IN THE MANUFACTURE OF CARDBOARD,
KNOWN AS DRAWING BOARD AND MOUNTING BOARD."
This Invention relates to a new method of treating cardboard, drawing board,
and mounting board during the operation of drying, and the object is to produce
sheets of cardboard, drawing board, and mounting board, the surface of which
shall be more flat and even, and less liable to become warped or bent than those
sheets of cardboard, drawing board, and mounting board which are dried and
finished in the ordinary way. For this purpose we construct pairs of frames (pre-
ferably of galvanised iron) the upper edges of which are milled diagonally. These
frames are made of sizes and shapes corresponding to the sizes and shapes of the
sheets of cardboard, mounting board, and drawing board to be manufactured, and
they have a flange projecting on each side in order that a pair of frames may be
firmly secured one upon the other (the diagonally milled edges face to face) by
means of clamps or other suitable fastenings placed at suitable intervals. In a pair
of these frames of suitable size and shape we secure a sheet of cardboard, drawing
board, or mounting board, and allow it to remain so secured during the operation
of drying.
The manner of securing a sheet of cardboard, drawing board, or mounting board
is as follows: One of these frames is first placed upon a bench or table, with its
diagonally milled edges uppermost, and the opening within this frame is filled in
with any clean and flat substance (by preference with a wooden board) the height
of which shall be as nearly as possible level with the upper part of the diagonally
milled edges of the said frame. Upon this wooden board a sheet of cardboard,
drawing board, or mounting board is so placed that it extends beyond the wooden
board in all directions, and covers the diagonally milled edges of the said frame.
Another frame of similar construction is next placed with its diagonally milled edges
downward upon the sheet of cardboard, but the direction of the milling of its edges
should be opposite to the milling of the edges of the first-named frame, that is to
say, that the diagonal milling of the one should cross the diagonal milling of the
other diagonally. In this position the pair of frames are secured by means of the
clamps above referred to. The sheet of cardboard being thus firmly secured between
the diagonally milled edges of a pair of frames is effectually prevented from warping
while drying, and the result is necessarily the production of a sheet of cardboard,
which is flat and even, and which also is less liable to warp or bend through change
of temperature or other fluctuations of the atmosphere than those sheets of the
same material which are allowed to warp during the operation of drying.
We use
frames with diagonally milled edges, because the milling, as above described, forms a
series of channels through which the air circulates freely, and thus the whole sheet
of cardboard is thoroughly dried.
This improved method of drying cardboard, drawing board, or mounting board
will be clearly understood by reference to the accompanying Drawings, which
represent one of the frames above referred to.
Fig. 1 is a plan shewing top side of a frame, with the diagonally milled
edge A.
Fig. 2, a side view shewing the flanges B, which receive the clamps for the pur-
pose of fastening two frames together, as above described. Fig. 3 represents a
clamp used for this purpose.
Having now described the nature of our said Invention and the manner in which
the same is to be performed, we wish it to be understood that we do not claim

page_text: the drying of cardboard, drawing board, or mounting board held at tension, but
what we do claim as new and useful, and as our Invention, is,—
1st. The construction of frames of any suitable material, with suitable fastenings
to hold them together in pairs for the purpose of holding sheets of cardboard,
drawing board, or mounting board at tension during the operation of drying.
2nd. The use of frames with diagonally milled edges, which milled edges not only
constitute a good form of edge for procuring a firm bite in holding the cardboard,
drawing board, or mounting board, but make a series of channels through which
the air circulates during the operation of drying, so that the whole sheet of card-
board, drawing board, or mounting board may be thoroughly and expeditiously
dried.
In witness whereof, I, the said Frederick Turnbull, have hereunto set my
hand and seal, this Seventh day of May, in the year of our Lord One
thousand eight hundred and seventy-eight.
FREDERICK TURNBULL. (L.S.)