IMPROVEMENTS IN BREECH-LOADING CANNON
Year: 1871

page_text: LETTERS PATENT to John Cameron Graham, of Ballewan, in the
County of Stirling, Scotland, at present residing at Shalford, in
the County of Surrey, Mechanical Engineer, for the Invention of
"
PROVISIONAL SPECIFICATION left by the said John Cameron Graham
at the Office of the Commissioners of Patents, with his Petition,
on the 29th April 1871.
I, JOHN CAMERON GRAHAM, of Ballewan, in the County of Stirling,
Scotland, at present residing at Shalford, in the County of Surrey,
Mechanical Engineer, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN BREECH-LOADING CANNON," to be as follows:-
My Invention consists in closing the breech end of the cannon which
is bored through by means of a slab of metal, a horizontal section of
which may be a very sharp wedge or a parallelogram made of steel or
other suitable metal, which slides transversely across the open breech
of the cannon in a slot way cut in a cap or breech block, also made of

page_text: steel or other metal, which is screwed by means of a screw thread cut in
the inside of the said breech block or cap upon a coarsely pitched
screw thread which is cut upon the outside of the rear or breech end of
the cannon and works easily upon it. This cap or breech block extends
some distance behind the termination of the cannon barrel, so that after
the transverse slot way has been cut through it there shall still remain
a thickness of metal behind this slot way as great or greater than the
width of the slot way.
The slot way is made of such dimensions as to allow of the slab or
wedge being introduced of sufficient breadth to more than cover the bore
of the cannon, and so cut that when the slab is pushed in it shall just
slide freely past the breech end of the cannon. Through that part of
the breech block or cap which projects beyond the rear or breech end of
the cannon and lies behind the slot way is bored a hole, somewhat larger
than the bore of the cannon and in continuation of the same, so that
when the slab or wedge has been pulled transversely from across the
breech of the barrel, a cartridge may be introduced into the gun through
this hole. When the slab or wedge has been returned to its place, a
rotatory motion round the axis of the cannon is given to it, and the cap
or breech piece by means of a tommy or hand spike screwed into the
end of the slab, which serves also as a handle with which to move the
slab backwards and forwards. The result of this rotatory motion is that
the cap or breech block is made to travel forwards up the cannon by
means of the screw thread, and is brought to rest by jamming the slab
tight against the rear end of the barrel of the cannon.
..
In order to facilitate the sliding of the slab or wedge backwards and
forwards in case it moves too stiffly to be moved easily by a direct pull,
I fix to the upper or lower side of the cap or breech piece (whichever
is most convenient), a bracket carrying a pinion which takes into teeth
cut in the slab or wedge, which when made to revolve causes the slab
or wedge to travel backwards or forwards.
I further have an arrangement consisting of a pin sliding in a hole
parallel to the bore through the rear end of the cap or breech block
which takes into holes in the slab-and prevents it from being withdrawn
too far or pushed too far-in.
And also I have a similar arrangement situated upon the cap which
takes into a hole in the cannon itself, and locks the whole mechanism, so
as to prevent any movement at the moment of discharge. If necessary

page_text: .there may be introduced between the slab and the charge of powder into
the bore of the cannon, chamfered purposely, a conical piece of metal,
which projecting slightly beyond the rear of the cannon becomes
jammed up tightly by the slab or wedge when it is screwed up ready
for firing, and prevents the escape of gas, or any other suitable con-
trivance may be employed for the same purpose. This method of
making the chamber gas-tight I do not, however, claim as part of the
Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Cameron Graham in the Great Scal Patent
Office on the 23rd October 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CAMERON GRAHAM, of Ballewan, in the County of Stirling, Scotland,
at present residing at Shalford, in the County of Surrey, Mechanical
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of April, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Cameron Graham, Her
special licence that I, the said John Cameron Graham, my executors,
administrators, and assigns, or such others as I, the said John Cameron
Graham, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 Inven-
tion for "IMPROVEMENTS IN BREECH-LOADING CANNON," upon the condition
(amongst others) that I, the said John Cameron Graham, 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 Seal Patent

page_text: Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said John Cameron Graham, 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 thercof, reference being had to the accom-
panying Drawing, and to the figures and letters marked thereon, that is
to say :-
My Invention consists in closing the breech end of the cannon which
is bored through by means of a slab of metal, a horizontal section of
which may be a very sharp wedge or a parallelogram made of steel or
other suitable metal, which slides transversely across the open breech
of the cannon-in a slot way or mortice cut in a cap or breech block also
made of steel or other suitable metal, which is screwed by means of a
screw thread or screw threads cut in the inside of the said breech block or
cap upon a screw thread or threads cut upon the outside of the rear
or breech end of the cannon, and works easily upon it. This cap or
breech block extends some distance behind the termination of the
cannon barrel, so that after the transverse slot way or mortice has been
cut in it there shall still remain the necessary thickness of metal behind.
this mortice, which may be as great or greater than the width of the
mortice.
The slot way or mortice is made of such dimensions as to allow of
the slab or wedge being introduced of sufficient breadth to more than
cover the bore of the cannon, and so cut that when the slab is pushed
in it shall just slide freely past the breech end of the cannon. Through
that part of the breech block or cap which projects beyond the rear or
breech end of the cannon, and lies behind the slot way or mortice is
bored a hole somewhat larger than the bore of the cannon and in con-
tinuation of the same, so that when the slab or wedge has been pulled
transversely from across the breech of the cannon a cartridge may be
introduced into the cannon through this hole. When the slab has been
returned to its place a rotary motion round the axis of the cannon is
given to it, and the cap or breech piece, by means of a suitable tappet
motion, or by means of a tommy or handspike screwed into the end of
the slab, which serves also as a handle with which to move the slab back-.
wards and forwards. The result of this rotary movement is that the
cap or breech block is made to travel forwards up the cannon by means

page_text: of the screw thread or threads, and is brought to rest by jamming the
slab tight against the rear end of the barrel of the cannon.
In order to facilitate the sliding of the slab or wedge backwards and
forwards in case it moves too stiffly to be moved easily by a direct pull,
I in some cases fix to the upper or lower side of the cap, whichever is
most convenient, a bracket carrying a pinion which takes into teeth cut
in the slab or wedge, which, when made to revolve, causes the slab to
travel backwards or forwards.
I also employ an arrangement consisting of a pin sliding in a hole
parallel to the bore through the rear end of the cap or breech block,
which takes into holes in the slab and prevents it from being withdrawn
too far or pushed too far in.
In some cases I employ a similar arrangement situated upon the cap
which takes into a hole in the cannon itself, thereby preventing the cap
and slab from rotating through the weight of the slab, when the slab
is drawn out for loading. If necessary there may be introduced
between the slab and the charge of powder into the bore of the cannon,
chamfered purposely, a conical piece of metal which projects slightly
beyond the rear of the cannon, and becomes jammed up tightly by the
slab or wedge when it is screwed up ready for firing, and prevents the
escape of gas, or any other suitable contrivance may be employed for the
same purpose. This method of making the chamber gas-tight I do not
however claim as part of the Invention.
The powder may be exploded by means of a pin passing through the
slab in the centre line of the cannon, or by any other suitable means.
In order that my Invention may be more fully understood I have
annexed Drawings hereto which I now proceed to describe.
In all the six Figures C represents the breech end of the cannon;
D, the cap or breech block; and E, the slab or wedge; F, the arrange-
ment for locking the slab; and H, the arrangement for locking the cap.
Fig. 1 represents the side elevation of a cannon with the breech
mechanism actuated by the tappet motion, and Fig. 2 the end elevation
of the same arrangement closed for firing; Fig. 3 is a section of the
same through the line A, B.
In Figs. 1, 2, 3, K is a wrought iron or a steel ring moving freely
round the cap D, but kept in its place by means of the two stops L, L',
which are screwed on to the cap D. Upon this ring are fixed two

page_text: weights W, W¹. When the ring and weights are made to revolve by
the handles M and M', they swing through nearly half a turn, and the
weights come into contact with the stops L, L, either tightening up the
cap or loosening it according to the side of the stops which have been
struck.
Figs. 4, 5, 6, represent the arrangement when a tommy or handspike
is used for opening the breech; Fig. 4 represents the side elevation;
Fig. 5 represents the cannon when the slab E has been withdrawn
ready for loading, and Fig. 6 represents the same arrangement when
the slab E has been returned to its place, and it and the cap screwed up
by means of the tommy T ready for firing.
Having now described my Invention and the manner in which it is to
be performed, I claim, —
First. The combination of parts forming the breech-loading cannon
constructed and arranged as herein described.
Second. I claim the use of the rotating breech block, in which a slab
or wedge slides transversely in a slot or mortice arranged as and acting
in the manner herein-before described.
In witness whereof, I, the said John Cameron Graham, have here-
unto set my hand and seal, this Twenty-third day of October,
in the year of our Lord One thousand eight hundred and seventy-
onc.