CERTAIN IMPROVEMENTS IN SAW MILLS
Year: 1813

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARC
ISAMBARD BRUNEL, of Chelsea, in the County of Middlesex, Civil Engineer,
send greeting.
WHEREAS His most Excellent Majesty King George the Third did,
by His Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Twenty-sixth
day of January, in the fifty-third year of His reign, give and grant unto me,.
the said Marc Isambard Brunel, my exors, adññors, and assigns, His especial
licence, full power, sole privilege and authority, that I, the said Marc Isambard
Brunel, my exors, adññiors, and assigns, should and lawfully might, during
the term of years therein mention, make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, my Invention of
"CERTAIN IMPROVEMENTS IN SAW MILLS;" in which said Letters Patent there
is contained a proviso that if I, the said Marc Isambard Brunel, shall not
particularly describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and cause the same to be inrolled in His Majesty's High
Court of Chancery within two calendar month next and immediately after
the date of the said Letters Patent, that then the said Letters Patent, and
all liberties and advantages whatsoever thereby granted, shall utterly cease,
determine, and become void, as in and by the same, relation being thereunto
had, may more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Mark Isambard Brunel, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are par-
ticularly described and ascertained in and by the Drawings hereunto annexed,
and the following description thereof (that is to say) :-
Fig. 1 represents the front elevation of a saw frame, sliding on three
points A, A, B, as the stretching of a number of saws in a frame has a
tendency to bend in the heads of the frame, and consequently of affecting the
sides in the same manner. The two bolts or ties C, C, are intended to form
a counteraction, which will keep the uprights D parallel to each other. The
lower slide or rod E' is intended to guide the recipracating mation of the
frame. This rod slides within a socket B, and in the direction it is represented
in Fig. 2. It is not parallel with the uprights D. This deviation, how-
ever small, gives to the frame,--when--in-action, a proportionate degree of
oscillation.
I
Fig. 2 represents a lateral section of the frame seen in Fig. 1, and shews at
the same time its inclination with regard to the angle it forms with the
carriage on which the timber to be sawed is laid. This frame is to alter its
inclination at every other stroke. The alteration is given to it by the aid of
the eccentric triangular piece F, which is put in motion by the interposition of
two cog wheels G, H, Figs. 1, 2, and 4, when the eccentric F is brought to the
opposite point to that in which it is now represented. It does in the action
of passing from one point to the other rise by the aid of the swinging frame
within which in revolves by the lever K, and inclines forward the moveable
carriage L, into which the socket B is fixed. This alternative motion alters
the inclination of the frame, as it is desirable that the saws should not press
against the wood when they ascend. propose, in order to accomplish this, to
have the socket A, A, Figs. 1 and 2, fixed to a double hinge or knuckle M,
Figs. 2 and 6. When the frame begins to ascend it carries along with it the
sockets A, which being confined by the hinge M, are drawn back as much as
is found requisite to relieve the pression of the saws against the wood. When
the frame descends, the sockets are returned to their former position. This
receding motion of the frame, which is intended chiefly to relieve the friction
of the face of the saws, may be effected by the aid of a slide similar to that
represented at A, Fig. 7. In lieu of a socket a slide acting upon a double
joint will recede as the side D of the saw frame ascends, and returns to its
former position when it descends. In this case a roller or spring slide is 'to
be applied in front in order to confine the side D close to the face of the

page_text: moveable slide.
The back motion of the frame, the chief object of which is
to relieve the friction of the saws when ascending, is to be affected in the
following manner, which in some cases is preferable to the two former before
described, see Fig. 8:-D represents one of the uprights of the frame sliding
through the socket A. This socket (or both if they could be seen, is fixed
on the frame L, which frame rests on a center C, on which it has a motion,
an eccentric wheel B revolving in a manner corresponding with the alter-
native motion of the saw frame; that is, when the frame ascends the narrower
part of the eccentric presents itself to the roller E, and its wider part where
it descends; by this alternative motion the frame is moved forward and back-
ward at pleasure. A saw frame, fixed in the manner represented in Fig. 8,
has the advantage that it may be laid horizontally for the purpose of whetting
and setting the screws with ease by the aid of an instrument. which will be here-
after specified. Two or more saw's might be carried in one single hook, repre-
sented in Figures 9, and stretched into the saw frame, with either screws or.
wedges in the manner specified by me in a former occasion. In order to equalize
the tightness of each of the several saws held by a single hook; small wedges
may be used, as represented in the Figure 9. As the saws I make use of in the
frame here described are stretched to their proper degree of tightness by
means of a lever, it is desirable that when the same saws require to be rectified
and whetted by the assistance of the apparatus represented in Figs. 10, 11,
and 12, which apparatus I have specified in a former occasion, they should
have a degree of tightness nearly equal; in order to produce this effect, I
propose to add to this apparatus a lever A, Fig. 10, resembling the beam of a
steelyard: The lever; by the interposition of the parts D, E, act on the
hook B, which stretches the saws at pleasure by turning the handle H. To
this lever a weight F is applied; and moved at pleasure to any distance from
the fulcrum C: The instrument represented in Figs. 13, 14, and 15 is
intended to assist in whetting the saws; it is added to the moveable car-
riage G, laid on the apparatus represented in Figs. 10 and 11. The .Fig. 13
represents to the lateral view of the instrument, Fig. 15 its plan, and Fig. 14
its section. It is adjusted by means of a screw to any height, according to
the edge of the saw, when they are fixed in the apparatus before mentioned.
A, Fig. 14, represents one of the moveable side pieces seen in the Fig. 15;
each of these side pieces carry a small rest B, of very hard steel, against which
every tooth of the saws lay during the operation of whetting. These moveable
slide pieces A may be used either singly or together. I prefer only one
at a time, as it enables to file with more ease the point of the teeth to any

page_text: angle; the side piece A on the side of the teeth to be filed, and the other
turned up.
These pieces are adjusted by means of small screws C, C, Fig. 15.
It is evident that with the aid of this instrument the teeth of the saws will be
whetted with great precision and uniformity. The carriage G is stopt to its
proper place by means of a small paul D.
It being desirable that the teeth of circular saws should be whetted with an
equal degree of precision, I propose to make use of an instrument constructed
on the same principle, adapted to the size of the saw. Circular files might
be used instead of strait ones, but I give the preference to strait ones.
When a great number of strait saws are fixed in frames, I propose, instead
of taking them off to be set and whetted, to perform the setting and
whetting in place either on the frame itself or on an apparatus capable of
receiving the same. This apparatus is represented in the Figs. 16, 17,
18, and 19. The Figure 16 represents the plan of the instrument; 17,
a longitudinal section; 18, a longitudinal elevation; and 19, a transversal
section.
The saw frame, as seen in part as represented at a, being laid between the
slides A, A, Figs. 16 and 19, the carriage B, B, Figs. 16, 18, and 19, is
brought over, and is moved at pleasure from end to end. The carriage is
composed of slides connected with each other, and framed together by bolts C
and E. The small socket, with a projecting arm D, is intended to slide in a
transverse direction on the bolt C. At the lower point of this arm a small
file is fixed, and in order to regulate the depth of the fileing, the upper extre-
mity of the arm rests on the second bolt E, on which it is adjusted at pleasure
with a screw F. It is obvious that by moving the arm D transversely the
file will act upon the teeth.
In order to guard against the jarring of the saws during the operation of
filing, I propose to introduce some intermediate pieces of the form repre-
sented at G, Figs. 16 and 17. These pieces are intended to move with the
carriage.
The various improvements herein specified refer only to those parts of the
Drawings which are either coloured or shaded.
In witness whereof, I, the said Marc Isambard Brunel, have hereunto
set my hand and seal, this Twenty-sixth day of March, in the
year of
our Lord One thousand eight hundred and thirteen.
MC JD BRUNEL. (L.S.).

page_text: AND BE IT REMEMBERED, that on the Twenty-sixth day of March,
in the year of our Lord 1813, the aforesaid Marc Isambard Brunel came
before our said Lord the King in His Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and
specified, in form above written. And also the Specification aforesaid was
stampt according to the tenor of the Statute made for that purpose.
Inrolled the Twenty-sixth day of March, in the year of our Lord One
thousand eight hundred and thirteen
Inrolled the Twenty-sixth day of March, in the year of our Lord One
thousand eight hundred and thirteen