IMPROVED MACHINERY OR APPARATUS FOR THE MANUFACTURE OF GUNPOWDER
Year: 1870

page_text: LETTERS PATENT to James Davidson, of Ludenham, in the County
of Kent, Millwright, for the Invention of "IMPROVED MACHINERY OR
APPARATUS FOR THE MANUFACTURE OF GUNPOWDER."
Sealed the 25th April 1871, and dated the 14th November 1870.
'
PROVISIONAL SPECIFICATION left by the said James Davidson at
the Office of the Commissioners of Patents, with his Petition, on
the 14th November 1870.
I, JAMES DAVIDSON, of Ludenham, in the County of Kent, Mill-
wright, do hereby declare the nature of the said Invention for " IMPROVED
MACHINERY OR APPARATUS FOR THE MANUFACTURE OF GUNPOWDER," to be as
follows:-
My Invention relates to that class of gunpowder which is technically
known as "pebble powder," and is used for large guns or ordnance, and
sometimes for blasting purposes. Pebble powder is made in cubes of
5/8 of an inch, more or less, according to the purpose for which it is

page_text: intended to be used, and is usually made up first into long sticks (of the
proper sectional area) which are subsequently cut up by hand by means
of knives into pieces or cubes of the proper size.
The object of my Invention is to effect the cutting up of the cake
powder into cubes of the proper size with greater facility and in a more
economical manner than heretofore, and to this end I first form the
powder into cakes of suitable thickness, and by means of metal plates
provided with V shaped projecting bars I indent or groove the cake
longitudinally, so that it can easily be broken up into long strips
or sticks.
In carrying out my Invention I do not find it necessary to break up
the cake into long sticks as heretofore, but I take it (grooved in the
manner described) and pass it between a pair of rollers or curved
segments provided on the surface or periphery with a series of projecting
longitudinal bars. I prefer to use two rollers or curved surfaces thus
armed, and I connect them together by toothed gearing, so that they
may act in concert. Upon passing the grooved cake of powder or
several sticks placed side by side between the rollers or curved surfaces,
the projecting bars thereon will come in contact with the cake powder,
and will crack it into pieces or cubes of the proper size.
The working parts of this apparatus may be worked either by hand or
by power, and the segmental curved surfaces may be made to reciprocate
by means of a lever or handle, or the cylindrical surfaces may be rotated
either by a winch or actuated by steam or other power.
As a modification of this arrangement I sometimes groove the cake of
powder transversely as well as longitudinally, and by passing the cake
of powder (so grooved or partially divided) between rollers or segmental
surfaces armed with V shaped points, I break up the cake into cubes of
the desired size.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of November, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said James Davidson, Her special licence that I,
the said James. Davidson, my executors, administrators, and assigns, or
such others as I, the said James Davidson, 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 "IMPROVED MACHINERY OR APPARATUS
FOR THE MANUFACTURE OF GUNPOWDER," upon the condition (amongst others)
that I, the said James Davidson, my executors or administrators, 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 Scal Patent Office within six.
calendar months next and immediately after the date of the said Letters.
Patent.
NOW KNOW YE, that I, the said James Davidson, do hereby declare
the nature of my 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 Drawing hereunto
annexed, and to the letters and figures marked thereon (that is
to say)
My Invention relates to that class of gunpowder which is technically
known as "pebble powder," and is used for large guns or ordnance, and
sometimes for blasting purposes. Pebble powder is made in cubes of
five-eighths of an inch, more or less, according to the purpose for which
it is intended to be used, and is usually made up. first into long sticks (of
the proper sectional area) which are subsequently cut up. by hand (by
means of knives) into pieces or cubes of the proper size.
The object of my Invention is to effect the cutting up or dividing of
the cake powder into cubes of the proper size with greater facility and
in a more economical manner than heretofore. The several Figures in
the accompanying Drawing represent the improved machinery whereby
this object is cffected.

page_text: Fig. 1 is a longitudinal vertical section of the machine; Fig. 2 is an
end elevation, and Fig. 3 a side elevation showing the driving gear
whereby the several working parts are actuated. I first form the
powder into cakes of suitable thickness, and by means of metal plates
provided with V shaped projecting bars I indent or groove the cake
longitudinally, so that it can easily be broken up into long strips
or sticks.
In carrying out my Invention I do not find it necessary to break up
the cake into long sticks, as heretofore; but I take it (grooved in
the manner described) and pass it through the machine shown in the
Drawings.
The indented slabs or cakes of powder are placed on the inclined
fecding board a, a, Fig. 1, which conducts the slabs in succession to a
pair of rollers 6, b, provided on the surface or periphery with a series of
projecting longitudinal bars made of brass, and shewn best at Fig. 4,
which is a detached view of part of the periphery of these two rollers
drawn upon an enlarged scale. I prefer to use two rollers, as shewn in
the Drawing, and thus armed I connect them together by toothed
gearing b¹, b', as shown at Figures 2 and 3, so that they may act in
concert, but the same object may be effected by segments of cylinders,
which may be worked in concert by means of segmental racks and a
rocking or vibrating motion must be given to them instead of a con-
tinuous rotary motion. Upon passing the grooved cake of powder
or several sticks placed side by side between the rollers or curved
surfaces b, b, the projecting bars thereon will come in contact with the
cake powder, and will crack it into pieces or cubes of the proper size.
These cubical pieces of powder fall down into a screen f, to which a
vibrating or shaking motion is communicated by a band or strap f",
secured at its lower end to the screen f, and by its upper end to a crank
on the shaft g, which is rotated by means of a driving band h, which
passes from a pulley i on the main driving shaft to a similar pulley on
the crank shaft above. By the vibrating motion of the screen-f, the
cubes of powder are shaken down into any suitable receptacle beneath
the dust from the powder being allowed to pass through the screen and
fall into another receptacle below.
In practice it is found that the cakes or sticks of powder will sometimes
vary slightly in thickness, and therefore if the shafts of the rollers b, b,
were both mounted in rigid and unyielding bearings they would some-

page_text: times crush instead of simply cracking the powder. To obviate this I
mount the upper roller in a bearing fixed on the cross beam j, which
being mounted on a centre pin j¹ is capable of rising and yielding to a
certain extent when any hard substance is passed between the rollers.
If the entire weight of the roller and its accessories were allowed to
press on the cake powder it would be crushed, and the cubes would
be spoiled in shape. To obviate this a portion of the weight of the
roller is counterbalanced by means of the weights k, which are capable
of regulation and adjustment.
It will be evident that springs may, if preferred, be used to effect the
same object. In order to keep the rollers b, b, clean and prevent the
grains of powder from being retained between the projecting nipping
edges, copper knives , l, are adapted to each roller and made to lay near
or against the surface so as to remove any grains of powder which
may adhere thereto.
The working parts of this apparatus may be worked either by hand or
by power, and the segmental curved surfaces may be made to reciprocate
by means of a lever or handle, or the cylindrical surfaces may be rotated
either by a winch, or actuated by steam, or other power by means of
pullies and bands, as shewn in the Drawing. To this end a fast and
loose pulley c, c, are mounted on the main driving shaft d, and aro
actuated by any prime mover. On the shaft d is keyed a pinion e, which
gears into one of the large toothed wheels b', 61, and thereby actuates
the cylinders b, b.
As a modification of this arrangement shewn in the Drawing and
just described, I sometimes groove the cake of powder transversely
instead of longitudinally, and by passing the cake of powder (so grooved
or partially divided) between rollers or segmental surfaces armed with
V shaped points I break up the cake into cubes of the desired size.
Having now described my Invention of improved machinery or
apparatus for the manufacture of gunpowder, and having explained
the manner of carrying the same into effect, I claim as the Invention
secured to me by Letters Patent as aforesaid, the construction and
arrangement of parts herein shown and described, or any mere modifi-
cation thereof, in which rollers or curved or segmental surfaces armed
with projecting bars or points are employed to crack or break up cakes,

page_text: or sticks made of a gunpowder composition into cubes, as herein set
forth, so as to produce what is technically called "pebble powder."
In witness whereof, I, the said James Davidson, have hereunto
set my hand and seal, the Eleventh day of May, in the year of
our Lord One thousand eight hundred and seventy-one.
E