IMPROVEMENTS IN BREECH-LOADING FIRE-ARMS
Year: 1871

page_text: LETTERS PATENT to Alexander Crichton, of 16, Shepperton Cottages,.
Islington, in the County of Middlesex, Millwright, for the Invention
of "IMPROVEMENTS IN BREECH-LOADING FIRE-ARMS."
PROVISIONAL SPECIFICATION left by the said Alexander Crichton at
the Office of the Commissioners of Patents, with his Petition, on the
9th June 1871.
°
I, ALEXANDER CRICHTON, of 16, Shepperton Cottages, Islington, in
the County of Middlesex, Millwright, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN BREECH-LOADING FIRE-ARMS," to be
as follows:-
My improvements relate to the construction of the breech and lock
mechanism of breech-loading fire-arms.
I mount the breech block so as to oscillate on a centre near its hinder
end, rounding the end of the block so as to work in a cylindrical recess
in the lock frame, and thereby to deliver the pressure of the discharge,
not on a pin but on the solid part of the lock frame. The breech block

page_text: contains at its front end a sliding rod pressed lightly backwards by a
spring, which rod is struck forwards by the trigger action, as will here-
after be described. Behind this sliding rod the breech block is hollowed
out, so as to receive in its cavity a cam-shaped lever, the front of which
is made to act as a hammer. This lever is mounted on a pivot and is
pressed forwards by a strong spring. The lever has a tail projecting
downwards like a trigger from the lock frame; it has also a portion of
its boss made cylindrical with two notches on it, one for half-cock and
one for full-cock. A pawl pressed by a spring is fitted to enter either
of these notches, and this pawl can be drawn out of the full-cock notch 1
by the pressure of the finger on a knob projecting downwards from the
lock frame. In the front part of the lock frame there is mounted in a
slot a bent lever to act as an extractor. The one end of this extractor
lever projects into the bore of the breech immediately in front of the
flange of the cartridge. The other end of this extractor lever projects
below the breech block, which comes to bear upon it when it is pulled
down.
The action of the apparatus is as follows:-The breech block, which
oscillates on its end bearing, being down, the breech of the gun is open
to receive a cartridge. At the same time the pawl is in the full-cock
notch. The cartridge being inserted the knob can be pressed by the
finger. This releases the pawl from the notch, and thus leaves the cam
lever free. The strong spring acting on it causes it to turn on its pivot.
Its cam-shaped end working in the cavity of the breech block raises tho
breech block so as to cover the cartridge, and the farther movement of
the cam lever brings its hammer end to strike on the end of the sliding
rod and push it forward so as to discharge the fulminate of the cartridge.
After the discharge the projecting tail of the lever is pushed forward.
The cam end of the lever acting in the cavity of the breech block causes
it to descend so as to uncover the end of the cartridge. The breech
block in descending bears upon the extractor lever, and thereby causes
it to push out the cartridge from the breech. The breech block having
completed its descent is held down by the pawl entering the notch upon
the boss of the lever. Another cartridge can now be inserted and the
action repeated.
When it is desired to have the piece on half-cock the tail end of the
cam lever instead of being pushed quite forward is only pushed far
enough to let the pawl enter the half-cock notch. The piece can then

page_text: be kept in this condition as long as may be required. It can then be
put on full-cock by pushing the tail end of the lever fully forward, when
the discharge of the piece can be effected by pressing the knob as already
described.
I am aware that breech blocks have already been mounted on pivots
at their hinder ends, their front ends oscillating so as to expose and
cover the breech. I therefore lay no claim to such breech blocks unless
when constructed as I have described. The nature of the mechanism
which I have described for moving the breech block and for discharging
the piece enables me so to construct the breech block that it is pivoted
centrally in the line of fire, and that the pressure of the discharge is
received not on a pin but on the solid metal of the lock frame.
I am also aware that extractors have been made in the form of bent
levers acted on by the descent of the breech blocks, and I therefore lay
no claim to such extractors, except in combination with the mechanism
which I have described.
•
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Crichton in the Great Seal Patent Office
on the 9th December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
CRICHTON, of 16, Shepperton Cottages, Islington, in the County, of
Middlesex, Millwright, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her.
Letters Patent, bearing date the Ninth day of June, 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 successors,
give and grant unto me, the said Alexander Crichton, Her special licence
that I, the said Alexander Crichton, my executors, administrators, and
assigns, or such others as I, the said Alexander Crichton, 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
yend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands; and Isle of Man, an Invention for "IMPROVEMENTS IN

page_text: BREECH-LOADING FIRE-ARMS," upon the condition (amongst others) that I,
the said Alexander Crichton, 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 i
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alexander Crichton, do hereby declare
the nature of my said Invention, and in what manner the same is to 1
be performed, to be particularly described and ascertained in and by
the following statement thereof, reference being had to the Drawings,
hereunto annexed, that is to say :-
This Invention rclates to certain improvements in those fire-arms
known as the "drop block" arm, whereby, firstly, the thrust or recoil 1
of the discharge is received upon a solid portion of the breech and
directly in line with the axis of the bore, in lieu of upon a pin and above
or below the line of the axis of the bore, as is the case with the arms
of this system hitherto constructed; and, secondly, to simplifying the
working portions of the lock mechanism to obtain easier opening 2
and closing of the block and a more efficient striking action for the
discharge.
The Invention will be well understood by reference to the accom-
panying Drawings, and to the following detailed description thereof :-
Figure 1 represents a sectional view of the breech portion of a gun
with my improvements applied thereto, the block being closed and in the
position it would occupy after a cartridge had been discharged. Figure 2,
which is also a sectional. view, showing the same block open and in the
position it is brought into by the cam to permit of the insertion of a
fresh cartridge.
a is the barrel, which is secured to the breech break off in the usual
manner, and b is a kind of box in which the block c is free to rise and
fall for closing and opening the arm, the face of the tang lump & being
recessed to receive the rear end e of the block to form a joint upon
which the block can oscillate, the joint being so made that the knuckle e
touches the recess fat all parts to ensure a good bearing, not only to
hold the block firmly within the recess but to form a solid connection,
so to speak, to resist the force of the recoil during the discharge of the
ย

page_text: arm, the centre of the knuckle being in line with the central line or
axis of the bore. The under side of. the block c has a chamber or
cavity g, in which a cam j on the upper end of the lever h is free to
move upon its supporting pin i when the breech has to be opened or
closed, the ends of the chamber forming butts or lugs against which
the head j can act. One portion of the head; is nose-shaped for
the free end of a single ended mainspring k to take against, another
portion / forming the hammer head by which the striker pin m is caused
to impinge against and puncture the cap in the base of the cartridge for
exploding the charge. The mainspring k is secured to the side walls of
the box so that by loosening one screw nail n the whole of the
mechanism can be removed in a body. The mainspring k has an extra
tail piece o forming a sear spring which causes the trigger lever or
paul p to bear against a rounded boss or shoulder q of the lever h and
to take into the half or the full bent which are cut in its face according
to the distance the lever is thrown forward to half or to full cock the
piece. The shoulder q'is formed in a slotted hole in the lever h, and
the end of the paul is protected by the side walls of the slot, so that
it cannot be caught to be acted upon under any circumstance and
relieved accidentally. The lever handle can be carried down to any
distance and be made to any shape for giving a good hand purchase for
opening purposes, the handle being thrown to the front to accomplish
this.
In the arm shown in Figures 1 and 2 it will be seen that no inde-
pendent closing of the block is necessary, consequently a great saving
of time is effected when rapid firing is being carried on, it being only
necessary to open the breech, when the empty cartridge case will be
withdrawn and ejected by the extractor r, the tail & of which is suddenly
struck by the block c in its descent; a fresh cartridge can then be
inserted and the trigger pulled, when the strength of the mainspring k
will cause the head j to lift the block into position, and then be
suddenly shot to the front and act upon the striker to discharge the
cartridge. Thus three motions only are required to accomplish the
object. These are, firstly, to throw the lever h to the front; secondly,
to insert a fresh cartridge; and, thirdly, to pull the trigger. In some
cases I divide the head or upper part of the lever / and use one portion
only to act upon the striker pin, the other portion being employed to
open and to close the breech without the trigger paul being interfered
with.

page_text: This modification permits of the block being closed or re-opened
while the striking mechanism is at full or half cock, and it also allows
of the mechanism being shifted from the full to the half cock position
without the opening lever being touched, an advantage not possessed by
other drop block arms at present in use without the employment of
special devices.
This modification is clearly shown in Figures 3 and 4, Figure 4
being a detached view of one of the striking portion of the lever h¹.
It will be seen that this piece, which I call the striker tumbler, is
fulcrumed upon the same pin i as the lever h, and its bottom has a
projection or lip t, which is borne against by a flat portion u of the
lever to cause it to turn to compress the mainspring and to allow of
the paul p taking into the half or the full bent as desired; the striker
tumbler then becomes locked, so, to speak, but the lever can be
returned and the block closed and re-opened as often as necessary
without fear of the tumbler escaping and causing an accidental
discharge should the barrel be loaded.
The lever tail 1, Figure 3, is shown curved towards the rear, so as
not to interfere with the movement of a soldier should the arm be
a military one, but it may be curved or shaped in any convenient
manner.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,—
Firstly. Hinging or jointing the block of drop-block firc-arms in a
recess in the breech and in line with the axis of the bore in the manner
shown and for the purposes described.
Secondly. I claim the employment of an opening, closing, and
striking cam j in drop-block arms acting in the manner shown and
described.
Thirdly. I claim the employment of a single-ended spring secured
behind the block for giving the direct impact to the striker cam of
drop-block arms, as described and shown.
Fourthly. I claim, the arrangement of mechanism for accomplishing
the opening and closing the blocks of drop-block arms, as described and
shown.

page_text: Fifthly. I claim the employment of a striker tumbler in combination
with and worked by the lever tail piece h, and when such tumbler has
the full and the half bents in it, for the purposes set forth.
In witness whereof, I, the said Alexander Crichton, have here-
unto set my hand and seal, this Eighth day of December One
thousand eight hundred and seventy-one.
ALEXANDER CRICHTON. (L.S.)