A NEW AND IMPROVED METHOD OF BENDING TIMBER
Year: 1855

page_text: LETTERS PATENT to Thomas Blanchard, Mechanical Engineer, of No. 2,
Rue Drouot, in the City of Paris, in France, for the Invention of "A
NEW AND IMPROVED METHOD OF BENDING TIMBER."
Sealed the 25th September 1855, and dated the 18th June 1855.
PROVISIONAL SPECIFICATION left by the said Thomas Blanchard at
the Office of the Commissioners of Patents, with his Petition, on the
18th June 1855.
I, THOMAS BLANCHARD, Mechanical Engineer, of No. 2, Rue Drouot, in
the City of Paris, in France, do hereby declare the nature of the Invention
for "A NEW AND IMPROVED METHOD OF BENDING TIMBER" to be as follows:-
This Invention consists in so conducting the process of bending wood or
timber that the piece of wood or timber may be subjected to pressure on all
its sides during the process of bending, in place of simply being bent over a
form, as has heretofore been the practise. By this means the wood or timber
is prevented from swelling or bursting, as it is liable to do when bent without
such support.
The apparatus which I employ consists of a lever, which turns on a centre
or axis; to this lever is attached a trough of the curve to which the wood is to
be bent, one side of the trough being moveable, so that it may be pressed -
firmly against the surface of the wood by wedges. Underneath the lever-before

page_text: mentioned is a travelling table, the distance of which from the curved form
can be adjusted by a screw. The piece of timber to be bent is laid on a flexible
band of metal placed on this table and clamped down thereon, so that it is
pressed upon on all sides; one end. of the timber is then clamped to the fore
part of the curved trough on the lever, the flexible band of metal being taken
hold of in the clamp as well as the timber. The other end of the timber buts
against a block, acted on by a screw, which passes through lugs in the
travelling table. When this is all arranged; the lever, is drawii' down, during
which operation the timber passes-into-the curved trough;-when-this is done
the two ends of the piece are connected together by a tie, which takes hold of
the ends of the flexible band before mentioned, and afterwards the wood, still
confined by the curved trough; the flexible band and the tie is removed from
the machine, and is so held until it is set.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Blanchard..ingthe, Great..Seal Patent, Office on the
5th October 1855.
.I
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BLANCHARD, Mechanical Engineer, of-No. 2, Ruo-Drouot, in the City of Paris,
in France, send greeting.
WHEREAS Her most Excellent. Majesty Queen Victoria, by Her, Letters
Patent, bearing date the Eighteenth day of June, in, the. year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of. Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Blanchard, Her special licence, tliat I, the said Thomas Blanchard,
my executors, administrators, and assigns, or such others as I, the said Thomas
Blanchard, 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 "A NEW AND IMPROVED METHOD OF
BENDING TIMBER, upon the condition (amongst others) that 1, the said Thomas
Blanchard, by an instrument in writing under my hand and seal, '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 imme-
diately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Thomas Blanchard, 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, reference being had to the annexed Drawings, that is to say:
Figure 1 is a plan, shewing the timber confined in the machine preparatory
to bending; Figure 2, a plan, shewing the timber after the bending is com-
pleted; Figure 3, a section upon the line A, A, of Figure 1; Figure 4, a section
upon the line B, B, of Figure 1; Figures 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
details which will, be referred to hereafter.
My Invention has for its object the bending of timber, both of small and
large dimensions; and consists in submitting it to pressure upon every side and
upon the ends during the operation. of bending,..by which means it is prevented
from swelling, bursting, or cracking at the point bent, as would otherwise be
the case were the timber bent without being thus confined.
To enable others skilled in the art.to understand. my Invention, I will
procced to describe the manner in which I have carried it out, and the
construction. of my machine. .C, Figure 11, is the bed-piece or foundation
of the machine, upon which. are secured the operating parts of the machine;
D, Figure 12, is the bending lever, which turns upon the centre E, rising from
the bed-piece; Fis, an abutment rising from the bending lever D, against
which the end of the timber. is pressed by the bending screw G, which bears
upon the clamping piece I; the end of the timber being firmly and securely
held.to.the. bending lever by: the pressuré between the abutment F and the
clamping piece I,.as.seen in Figures 1 and 2. Immediately back of the portion
thus held,. the timber is tightly confined in a trough or box, for the purpose,
as..before. mentioned, of preventing it from swelling or bursting; this is
accomplished in the following manner:-The bottom surface of the timber
rests upon the bed-piece..C, or upon the. plate Y', interposed between it and
the bed-piece. Upon one side it is supported by the truss, beam K, seen in
perspective in Figure.8, and upon the opposite side by the back support L
(Figure 9). Attached to this back supporting plate are two sliding clamps
M, which pass through mortices in the bed-piece (Figure 4), and serve, when
drawn up to the bed-piece by the keys a, to hold the back support rigidly in
place, and compress the timber between it and the truss beam. The timber
is confined and compressed. in a vertical direction by the following means:-
N (Figure 10).is.a metallic plate, which I call the "straight follower," (seen
in plan in Figure 1, and in red outline in Figure 2,) which is placed upon the
upper surface of the timber. .c are upright. rods,.which rise from the surface_
of the straight follower, and enter the slots in the hooked uprights d, attached

page_text: to the top edge of the back support L; the follower N is thus prevented from
being drawn longitudinally out of place; it is forced down upon the timber by
the wedge-shaped keys b, whereby the latter is compressed between it and the
bed-piece of the machine. The timber is thus held compressed in a trough
formed by the bed-piece C, or the interposing plate Y', the straight follower N,
the truss beam K, and the back support L; out of this trough it is drawn as it
is bent into a circular mould, which will be presently explained. The bed-
piece, straight follower, and back support remain stationary while the timber
is withdrawn, but the truss beam follows on with the timber, as will be here-
after more fully described. The circular mould which receives the timber as
it is drawn out of the straight trough is constructed as follows:-It is evident
that the curve of this mould must be struck from the centre of motion of the
bending lever D; and as it is necessary to retain the pressure upon the timber
for some hours after the bending is completed, in order to prevent it from
returning to its former shape or from bursting or cracking, it is desirable that
whilst this circular mould is capable of being so adapted to the bending lever
as to partake of all its motions, it should at the same time be so constructed
that it may be removed from the machine with the timber without relieving
the latter from the compression to which it is subjected; this is accomplished
in the following manner :-The bottom and one side of the circular mould are
formed by what I denominate the "mould "O, seen in perspective in Figure 6,
and in section in Figure 3. This mould is adapted to a recess P, formed for
the purpose in the bending lever D, and is furthermore secured thereto by a
pin attached to the mould which enters the hole g in the bending lever.
When this mould is in place, and the timber is in the machine' ready for the
bending operation, the log is slightly entered into one end of the mould O, as
at a, Figure 1. The "circular follower" Q, seen in red in Figure 2, and in
perspective in Figure 7, is thus placed upon the log, upon which it is confined
by the wedge keys m, driven beneath the hooks n.
I have now described the means by which the log is confined, and prevented
from cracking and splitting upon every side except upon the outside or convex
part of the bend. This portion of the timber-is confined and prevented from
bursting out as it is bent by the following means:-R (Figure 13) is a hoop
or strap which is made to embrace the log upon the outside, as seen in
Figure 2. This strap is flexible, and may be made of iron or of steel. p and q
are returns at right angles to the strap which pass over the ends of the timber,
and against which the upsetting or end pressure is made to bear. S is the
clamping screw, the end of which bears against a block t; this block pivots
round the point, and carries the roller w, which, by the operation of the

page_text: screw S, is forced against the truss beam K; this latter, while it is held up
tightly against the timber, is thus permitted to slide past the roller as the
timber is drawn out of the machine. T, V, X, Y, is a train of gear wheels,
actuated by any sufficient power, and giving motion to a shaft Z, by the
revolution of which through a rope or chain the bending lever is set in
motion. Any other efficient means may be employed for the purpose of
actuating this lever.
By the means above described the timber is confined on every side, and
compressed while being bent; this is necessary for all large timber to prevent
it from cracking and bursting, but it is absolutely essential for all timber,
small as well as large, that it be compressed upon the ends previous to the
commencing of the operation, or that it be not allowed to elongate upon
the outside. This I effect in the bending of timber of moderate size in the
following manner:-The timber is cut of a length just to fit between the
returns p, q, of the strap R; the follower or plunger A² is then caused to rest
against the end of the timber, the return g of the strap R interposing between
the two; a sufficient amount of end pressure is then put upon the log by the
upsetting or beam screw B³, which works in the truss beam K, the other end
of the log being held by the clamping piece I for most light work, and for
nearly all small articles. This upsetting or end pressure is all that is necessary
to enable the wood to be bent to any required curve. Among such articles
may be enumerated plough handles, felloes of wheels, and the different parts
of furniture. Where ships' knees and other heavy timber are to be bent, it
becomes necessary, in addition to the end pressure, to submit the wood to side
pressure, in the manner already described, otherwise there is danger that it will
swell and crack during the bending process, by which its integrity and strength
are greatly impaired, if, indeed, it be not rendered useless.
The timber having been squared or brought into the required form, is cut of
a length that shall just fit into the strap R; it is then placed upon the bed-
piece, as seen in Figure 1; one end of it being clamped to the bending lever
between the abutment F and the clamping piece I, operated by the screw G.
The mould O is then inserted in the recess in the lever D, one end of it just
entering beneath the timber at æ; the curved follower Q is placed upon the
timber and keyed down by the keys m, as already described. The "back
support "L is then placed behind the log, it being made to enter in between
the mould and the curved follower Q, as seen in dotted lines in Figure 1, that
no considerable portion of the log may be left unsupported. The back support is

page_text: drawn up to the log by the keys a, which pass through the sliding clamps M,
projecting from its lower edge, and serve to hold it to the bed-piece.
The straight follower N, which covers the log, is so made as to adapt it to
the curved follower. Qat the point y, that the timber may at no moment be
relieved from pressure as it is drawn from the straight follower, and enters
beneath the curved follower Q. To the other side of the timber is applied the
truss beam K, which, unlike the other side supports of the log, is not made
fast to the bed-piece, but moves with the log as the bending proceeds; the truss
beam is made to bear upon the log by the key, and also by the clamp screw S,
the roller W permitting the truss beam to move freely along with the log.
The plunger A is now laid in, as seen in Figures 1 and 2, and by means of
the upsetting screw B² is made to bear against the end of the log with the
required force. Upon the outside of the strap R are projections C², D², which
enter corresponding recesses in the clamping piece I and truss beam K, by
which means not only is the timber forced to move with the bending lever D,
but the. truss beam and upsetting screw are caused to follow and move with
the timber:
In bending heavy timber, and where great strength is required, a strong flat
chain may be employed to surround. the outside of the log; this may be used
either in conjunction with the strap R, or it may be employed alone; in such
case, as the chain cannot yield, it is evident that the outside of the timber, as
well as the inside will be compressed, unless some means be resorted to
to relieve the end pressure as the bending proceeds; this may be effected by
turning back the upsetting screw by hand or by self-acting machinery, actuated
by the motion of the bending lever. To facilitate this operation, I have
adopted the arrangement represented in Figure 14; in which H is the timber
to be bent; A³, a metallic plunger, which receives the pressure of the upsetting
screw B³ this plunger passes through the return q' of the strap, which
encircles the timber and bears upon the metallic follower r, which rests
against the end of the timber. Outside of the interior strap is a secondary
strap or chains, which is secured, as before explained of the strap R, to the
beam K and clamping piece I. As now the bending proceeds,-and-it becomes
necessary to permit the timber to elongate to prevent the compression and
crippling of the outer surface, the end pressure is gradually relieved by
relaxing the screw E³, and is thus prevented from increasing to an injurious
or useless degree.
The parts being arranged as above described, motion is communicated to
the lever D around its centre E by the means described, or in any other
suitable manner, and this lever is brought into the position seen in Figure 2,

page_text: the timber being gradually bent and drawn out of the straight box in which
it was first confined and transferred to the circular mould O, in which it still
remains clamped. It is now necessary that the timber remain compressed
and confined for several hours; and in order that the machine may be used
for the purpose of bending another stick, the bent timber is removed in the
following manner from the machine:-H³ is a bar, having hooks upon its ends,
which are made to enter hooks or eyes in the returns p and q of the strap R.
The timber is thus prevented from springing back when it is relieved from
the end pressure, and it may then, with the parts in which it is confined
(Figure 5), be removed from the machine, which may then be used to bend
another stick.
What I claim as my Invention, and desire to secure by Letters
Patent, is,
First, subjecting the timber to pressure upon all sides during the opera-
tion of bending, in the manner and for the purpose substantially as herein
set forth.
Second, the within-described machine for the purpose of bending timber,
consisting essentially of the following elements, or their equivalents, in combina-
tion: First, the bending lever; second, the device for compressing the timber
while it is being bent; third, the curved mould in which the pressure is
continued, and in which the timber is removed from the machine after the
bending operation is completed.
Third, transferring the timber, during the operation of bending from the
straight box in which it is first compressed to the curved mould in which
it is removed from the machine, in the manner substantially as herein
set forth.
In witness whereof, I, the said Thomas Blanchard, have hereunto set
my hand and seal, this Twenty-seventh day of September, in the year
of our Lord One thousand eight hundred and fifty-five.
0
THOS BLANCHARD. (L.S.)
Witness,
T. BASSET, of Paris.