Improvements in or relating to Automatic Guns.
Year: 1895

page_text: Date of Application, 20th Mar., 1895
Complete Specification Left, 19th Dec., 1895--Accepted, 1st Feb., 1896
PROVIDIUNAL DECIFIONTIO
Improvements in or relating to Automatic Guns.
I, HIRAM STEVENS MAXIM, of Baldwyn's Park, Bexley, in the County of
Kent, Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
In automatic or "Maxim" guns as at present constructed there is on the forward
end of the breech-block or lock a cartridge-carrier or sliding piece which acts to
draw the cartridge from the belt, lower it, thrust it into the barrel and extract the
empty case. This carrier in moving forward with the breech-block or lock, rises
as it approaches the breech; in fact, as the centre of the toggle-levers by which
the breech-block is operated is slightly above the centre of the barrel it is
necessary that the cartridge carrier should actually rise after the breech is closed.
It therefore follows that the cartridge-carrier cannot press with any degree of
force against the cartridge-case, otherwise it would bind and prevent the cartridge-
carrier from completely performing its upward movement. Consequently a little
space always has to be left between the cartridge-carrier and the cartridge-case to
avoid this binding and therefore when the breech is closed by the cartridge-carrier
there is not a firm metallic backing to the cartridge.
Moreover, the primers of the new smokeless powder cartridges have to be made
sufficiently thick to resist an enormous pressure, and therefore a very strong blow
of the firing pin is required to make them detonate. The force of this blow not
only pushes the lock back, but also pushes the cartridge forward or away from the
face of the carrier and any lost motion in the parts or any allowance made for
thick or dirty cartridges, serves to increase the space or distance between the face
of the carrier and the head of the cartridge, so that when the cartridge explodes
the head moves back through this space, and this movement together with that
arising from the elasticity of the side plates, the crank and connections, will be
sufficient in many cases, unless the metal of the cartridge case is of the very best
quality, to break the same into two pieces one of which remains in the cartridge
chamber and thereby stops the firing.
In order to obviate this difficulty I have, according to my present invention,
devised means which cause the cartridge carrier or slide to rise and seize the new
cartridge in the belt, and then, after all the parts have assumed their proper
position, cause the breech block or lock to complete its forward movement and
press the carrier or slide firmly against the head of the cartridge in the cartridge
chamber by the action of the toggle-levers, so that at the instant of firing, the
cartridge is firmly pressed into the cartridge-chamber and all the lost motion is
taken up.
66
Heretofore, whatever energy there might be in the crank-handle when the latter
returns into the firing position has been taken up by what is known as the
dead-stop." I propose now to utilize a portion of this energy, through the
intervention of the toggle-levers, to press the cartridge into the cartridge chamber
and to take up all the lost-motion in the various moving parts of the gun. By
this means the cartridge-carrier will be free to rise, because the breech is not
closed while the carrier is moving, and the energy which is generally absorbed in
the dead stop is utilised by the toggle-levers to press the carrier firmly against the
barrel and the cartridge. In order to adjust the mechanism to suit any thickness
of cartridge head, I provide means for lengthening the connecting-rod in such a
manner as to make it easily adjustable to any cartridge.

page_text: In the present most common forms of the Maxim gun, the safety-sear is liberated
at the time that the carrier is moving. This arrangement requires a very fine
adjustment, because the sear has to release the firing pin at the exact instant that
the carrier reaches its highest position, and it is found that when slightly worn the
parts get out of adjustment, but with my improved arrangement, whereby the
carrier first completes its vertical movement and then the crank handle travels
through an appreciable distance after the completion of this movement, such very
fine adjustment is not necessary and this difficulty is therefore entirely obviated.
Moreover there is also occasionally some inconvenience arising from the rebounding
of the carrier after it has been fully raised, thus bringing the firing pin hole in the
carrier a little below the centre of the primer. In such cases the action of the
firing-pin is interfered with and it is sometimes broken. By my present improve-
inents the bell-crank levers, while raising the carrier, have no movement whatsoever
except with the said carrier, their ends exactly fitting and working between the ears
that are on the carrier. I so form the said ends of the bell-crank levers that they
raise the carrier while the crank-pin is still below the centre. When however the
carrier has reached its uppermost position and ceases to rise any further the bell-
crank levers move a certain distance independently of it. In this manner the last
portion of the travel of the toggle-joint (i.e. when it is assuming the position in
which the greatest purchase or effect upon the breech-block is obtained) is
utilised for closing the breech and not for raising the carrier as heretofore.
Moreover, the bell-crank levers, in moving independently of the carrier as
above stated present their ends to the carrier in such a manner that it is
impossible for the said carrier to descend until released again by these levers, thus
locking the carrier firmly in its elevated position and preventing any damage to
the firing-pin.
A suitable projection is made on each of the bell-crank levers so that when the
breech is opened, the toe-pieces of the side levers of the lock which operate the
said bell-crank levers are brought into contact with the said projections thereby
throwing the bell-crank levers into such a position that they release the carrier and
permit it to descend in the usual manner. By this arrangement, the spring that is
generally attached to one of the inside plates of the gun and that engages with a
notch in the carrier and holds it in its uppermost position at the instant of firing,
may be dispensed with.
By my present invention it will be seen that all the parts that act to hold the
cartridge in the barrel at the instant of firing are put into the best position for
offering the greatest resistance to the stress due to discharge, before the cartridge
is struck by the firing pin.
Improvements in or relating to Automatic Guns.
I, HIRAM STEVENS MAXIM, late of Baldwyn's Park, Bexley in the County of
Kent, but now of 18 Queen's Gate Place, in the County of Middlesex, Mechanical
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
In automatic or "Maxim" guns as heretofore constructed there is on the forward
end of the breech-block or lock a cartridge carrier or sliding piece which acts after
each discharge of the gun to simultaneously withdraw the empty cartridge-case
from the barrel and a fresh or loaded cartridge from the belt, then to lower the said

page_text: cartridge and cartridge case, then to thrust the fresh cartridge into the barrel and
the cartridge case out through the ejecting orifice, and then finally to engage with
another cartridge in the belt ready to repeat its cycle of operations upon the next
discharge of the gun. The said carrier thus has four movements, viz.: a backward
movement with the lock; a downward sliding movement on the lock, a forward
movement with the lock, and lastly an upward sliding movement on the lock. In
order that the last of these four movements may be properly performed it is
necessary to prevent undue pressure between the face of the carrier and the base
of the cartridge otherwise the carrier would bind against the cartridge. Conse-
quently the space usually left between the face of the carrier and the end of the
gun-barrel when the carrier is in its most forward position is slightly in excess of
the thickness of the flange or rim of the cartridge. It follows therefore that when
the breech is closed the cartridge is not firmly supported. This evil is aggravated
when modern smokeless powders are used, for in such instances the primers have
to be made sufficiently thick to resist an enormous pressure, and therefore a very
strong blow of 'he firing pin is required to make them detonate. The force of
this blow not only pushes the lock back but also pushes the cartridge forward or
away from the face of the carrier, and any lost motion in the parts or any
allowance made for thick or dirty cartridges serves to increase the distance
between the face of the carrier and the base of the cartridge. When the
gun is fired the cartridge therefore recoils through such distance, and this
movement together with that arising from the elasticity of the side plates, the
crank, and the connections will be sufficient in many cases when the metal of the
cartridge is not of the very best quality, to break the cartridge into two pieces, one
of which remains in the cartridge chamber and thereby stops the firing.
In order to obviate this difficulty I have according to my present invention,
devised means whereby the cartridge carrier or slide performs five operations
instead of four as heretofore, that is to say it acts (1) to draw a cartridge from
the belt (2) to lower it into position for loading (3) to thrust it into the barrel
(4) to rise and seize a new cartridge and (5) to close firmly against the base of the
cartridge in the cartridge chamber. The energy possessed by the crank at
the moment of closing the breech and heretofore generally absorbed by the "dead
stop" is by this improvement utilized, through the toggle formed by the crank and
its connecting rod,-to press the carrier firmly against the base of the cartridge, so
that, at the instant of firing, the cartridge is firmly held in the cartridge chamber
and all lost motion is taken up. I also provide means for adjusting the length of
the said connecting rod to accommodate cartridges having base flanges of different
thicknesses.
"
In the present most common forms of the " Maxim gun the hand-sear is
released just prior to the completion of the upward movement of the carrier, and
the safety-sear is operated to release the firing pin at the exact instant that the
carrier reaches its highest position. A very fine adjustment of the parts is
therefore necessitated and it is found that, when slightly worn, the parts get out of
adjustment, and do not properly operate. But with my present improvements
whereby the carrier first completes its vertical movement and then the crank
handle or arm travels through an appreciable angle to press the carrier against the
base of the cartridge, such very fine adjustment of the parts is unnecessary and the
difficulty above indicated is avoided. Moreover the present improvements obviate
the inconvenience sometimes heretofore caused by the rebounding of the carrier
after it has been fully raised, thus bringing the firing-pin hole in the carrier a little
below the centre of the primer. In such cases the action of the firing-pin is
interfered with and the said pin is sometimes broken.
The spring that is generally attached to one of the inside plates of the gun
and that engages with a notch in the carrier and holds it in its uppermost
position at the instant of firing, can according to my present. improvements be
dispensed with.
In order that my said invention may be clearly understood and readily carried

page_text: into effect I will proceed to describe the same more fully with reference to the
accompanying drawings, in which:
Figure 1 is a longitudinal section of the rear portion of a gun shewing the
breech mechanism provided with any improved cartridge carrier.
Figure 2 is a detached sectional elevation shewing the breech-block or lock and
parts connected therewith in a firing position.
Figure 3 is a similar view shewing the parts in a recoiled position.
Figures 4 and 5 are sectional elevations similar to Figures 2 and 3 but shew a
modified construction.
Figures 6 and 7 are respectively a longitudinal section and rear end view of a
detail hereinafter more fully referred to.
In all these figures like letters of reference indicate similar parts.
B is the barrel. C is the
A is the frame enclosing the breech mechanism.
breech-block or lock body. D is the crank-shaft. D¹ is the crauk. D2 is the
crank pin. E is the connecting rod coupling the crank to the lock. E' is the pin
connecting the rod E to the lock. F is the cartridge-carrier which is capable of
sliding up and down on the forward end of the lock body. G1 G2 are the arms of
one of the bell crank-levers used for raising and lowering the cartridge carrier;
the said lever is pivoted to the lock body at G. FF are ears or lugs on the side
of the cartridge carrier between which the forward end of the bell-crank-lever
works. H is a toe-piece or finger forming part of the connecting rod and adapted
to operate the bell-crank-lever. There is one such toe-piece or finger and one such
bell-crank-lever on each side of the lock. J is the firing pin. K is the tumbler.
Lis the hand sear. M is the safety sear. Except as hereinafter described the
construction and operation of the above mentioned parts are substantially the
same as heretofore.
Referring now more particularly to Figures 2 and 3 the uppermost ear or lug Ft
of the carrier F is formed with a curved face f the radius of whose curvature is
equal to the length of the arm G2 of the bell crank lever measured from the
centre of the pivot-pin G. The extremity G* of the said arm G2 is also corre-
spondingly curved. At the time the lock is in its recoiled position (Figure 3)
the aforesaid curved extremity Gx of the arm G2 lies between the ears or lugs F
on the cartridge carrier. When the lock moves forward to close the breech the
toe-piece H acts on the face g2 of the arm G1, thereby turning the bell-crank-
lever about its fulcrum and causing the arm G2 to elevate the cartridge carrier.
During the rise of the carrier the curved extremity Gx of the arm G2 gradually
alters its position relatively to the ears or lugs F and when the said carrier has
fully completed its upward movement the end of the arm G2 escapes from between
the ears or lugs and brings its curved extremity GX against the curved face f of
the uppermost ear or lug F. The bell-crank lever continues to turn about its
fulcrum during the final closing movement of the lock and the curved extremity G*
of the arm G2 slides on the curved face f without further raising the carrier.
The parts thus assume the position shewn in Figure 2, the arm G2 of the bell-
crank-lever at this time acting as a strut to firmly support the carrier in its raised
position. The extremity Gx of the arm G2 is provided with a stop G3 which
limits the extent of the upward movement of the bell crank lever and prevents
the possibility of the arm G2 becoming entirely disengaged from the ears on the
cartridge carrier. During the recoil movement of the lock, the toe-piece H
strikes against a projection G on the arm G2 and thereby turns the bell crank
lever about its fulcrum until the curved extremity Gx of the said arm again enters
between the ears F¹. The carrier is thus released and descends in accordance
with the requirements of the working of the gun.
To ensure the proper engagement of the carrier with the rim of a cartridge as
the said carrier ascends, I make the upper end of the flange of the said carrier
inclined as shewn at F2.
According to the modified construction illustrated in Figures 4 and 5 I form
the arm G near its pivot G, with a curved face g¹, the radius of whose curvature

page_text: s equal to the length of the toe-piece H measured from the centre of the
bivot E¹. The extremity of this toe-piece is also curved in correspondence with
the curvature of the face g¹. The corner between the face g¹ and the face 92 may
be recessed as indicated at g³, or the two faces may merge one into the other.
During the first part of the forward movement of the lock from its position of
recoil shown in Figure 5, the extreme end or corner of the nearly vertical arm G¹
of the hell-crank-lever rests against the toe-piece H at a point near the pivot of
the latter. Hence during such movement the bell-crank-lever turns through a
very small angle, but, after the crank pin D2 has passed its lowermost position and
begins to rise towards the position shown in Figure 4 the point of contact between
the toe-piece H and arm G¹ is transferred to the extreme end or corner of the
toe-piece H which then bears against the arm G at a point approximately in the
line joining the centres of the pivots E' and G.
During the continued forward movement of the lock, therefore, the bell-crank-
lever is rapidly turned about its fulcrum and the carrier F is caused to rise into a
position where it engages with a fresh cartridge in the belt.
Since the bell-crank-lever turns about the fulcrum G and the toe-piece H turns
about the pivot E¹ it follows that during the rising movement of the cartridge-
carrier the point of contact of the toe-piece H and arm G¹ moves away from the
line joining the centres of the pivots E' and G and hence the corner of the toe-
piece H gradually moves over the portion g of the arm G¹ until it escapes past the
corner where the said portion g meets the curved face g¹. The carrier F then
ceases to rise, and the end of the toe-piece H, during the last stage of the forward
movement of the lock, moves over the curved face g¹ without producing any
further movement of the bell crank lever and firmly supports the carrier F in its
raised position.
It is during this final stage of the movement of the lock after the carrier F has
risen to its highest position that the connecting rod E operates to raise the safety
sear M thereby enabling the gun to be fired when the button that operates the
hand sear L is pressed in the usual manner. Moreover during this final stage of
the movement of the lock the face of the carrier F is pressed tightly against the
base of the cartridge and the end of the barrel by the toggle-like action of the
crank D¹ and connecting rod E.
In order to regulate this action as may be required I provide for varying slightly
the length of the connecting rod as follows. The rear end of the part of the said
rod shown in Figures 6 and 7 is made tubular and is furnished with inwardly
projecting lugs e equally spaced as shown in Figure 7 and adapted to engage with
similar equally spaced lugs e¹ (Figure 4) on the stem e2 of the other part of the
connecting rod. The said stem enters the tubular part and is enlarged at its rear
end to form an eye through which the crank pin D2 is passed. By sliding the
tubular part of the connecting rod over the stem e² so that the lugs e pass through
the spaces between the lugs e¹ on the stem e², and then by turning the tubular part
of the connecting rod through a fraction of a revolution so that the lugs e pass
behind the lugs e¹, the said tubular part of the rod can be locked to the other part
of the rod. The stem e² is screw threaded at e³ to receive a nut et which forms an
abutment for the end of the tubular part of the rod E. By screwing this nut one
way or the other the distance between the centres D2, E¹ can be increased or
diminished and the pressure of the lock against the end of the cartridge or of the
barrel, when the breech is closed, be thereby regulated.
The length of the neck or annular space formed in the stem e² behind the lugs el
is greater than the length of the lugs e and hence the latter can move axially on the
spindle in accordance with the adjustments of the nut et. A hardened steel
washer eis introduced between the nut e and the shoulder e to receive the thrust.
Washers of different thicknesses are used in accordance with the thickness of the
flange of the cartridges.
Instead of making the face g¹ curved as shewn in Figures 4 and 5 it may be
made straight.

page_text: In both of the above described devices it will be seen that the last portion of the
travel of the toggle-joint formed by the crank and connecting rod (i.e. when it is
assuming the position in which the greatest purchase or effect upon the breech-
block is obtained) is utilized for closing the breech and not for raising the
carrier.
Moreover it is impossible for the carrier after being raised to its highest point to
descend until released by the recoil movement of the connecting rod, thus preventing
any damage to the firing-pin.
By the present improvements it will also be seen that before the cartridge is
struck by the firing pin all of the parts that not to hold the cartridge in the barrel
at the instant of firing are put into the best position for offering the greatest
resistance to the stress due to discharge.
These improvements are applicable to guns wherein the energy for working the
parts is derived from the recoil of the barrel or from the recoil of the barrel
assisted by the pressure of the escaping gases acting on a piston arranged near the
muzzle of the gun, or from such pressure alone.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In an automatic gun a breech-block or lock "provided with a transversely
sliding cartridge-carrier which after each discharge performs the following cycle of
operations that is to say it acts first to draw a cartridge from the belt, secondly to
lower the cartridge into position for loading, thirdly to thrust it into the barrel,
fourthly to rise and seize a new cartridge, and fifthly to close firmly against the
base of the cartridge in the cartridge chamber after having fully completed its
upward movement substantially as described.
2. In an automatic gun the means whereby the upward movement of the
cartridge-carrier is completed before the termination of the forward movement of
the breech-block or lock, substantially as described with reference to Figures
and 3 or Figures 4 and 5 of the accompanying drawings.
3. The combination with the breech-block or lock of a connecting rod whose
length is capable of variation substantially as described and for the purpose
specified.
TX
101 1
1005
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.