U.S. patent number 3,675,534 [Application Number 05/030,492] was granted by the patent office on 1972-07-11 for automatic rifle.
This patent grant is currently assigned to Fabbrica D'Armi P. Beretta S.p.A.. Invention is credited to Pier Carlo Beretta.
United States Patent |
3,675,534 |
Beretta |
July 11, 1972 |
AUTOMATIC RIFLE
Abstract
An automatic rifle is disclosed, of the type which exploits the
pressure of the explosion gases for cocking the bolt, the
improvement consisting in a simplified arrangement for the guiding
tube in which the gas-actuated plunger or piston is slidably
housed. A limited number of component parts ensures a longer
service life for the rifle and the assembling and disassembling
operations are considerably facilitated. An improved sighting
arrangement is also disclosed.
Inventors: |
Beretta; Pier Carlo (Gardone
Val Trompia, IT) |
Assignee: |
Fabbrica D'Armi P. Beretta
S.p.A. (Gardone Val Trompia (Brescia), IT)
|
Family
ID: |
11148627 |
Appl.
No.: |
05/030,492 |
Filed: |
April 21, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Apr 29, 1969 [IT] |
|
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16212 A/69 |
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Current U.S.
Class: |
89/185;
89/191.01; 89/1.4; 42/148; 42/138 |
Current CPC
Class: |
F41G
1/16 (20130101); F41A 17/66 (20130101); F41A
3/26 (20130101); F41A 5/18 (20130101); F41G
1/48 (20130101); F41A 3/72 (20130101) |
Current International
Class: |
F41G
1/16 (20060101); F41A 3/72 (20060101); F41A
5/00 (20060101); F41A 17/66 (20060101); F41A
5/18 (20060101); F41A 17/00 (20060101); F41G
1/00 (20060101); F41A 3/26 (20060101); F41A
3/00 (20060101); F41G 1/48 (20060101); F41d
005/04 () |
Field of
Search: |
;33/53-58 ;42/1F,16A,17A
;89/185,191,192,193 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bentley; Stephen C.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. An automatic rifle comprising a barrel,
a receiver at one end of said barrel,
a guiding tube mounted parallel to said barrel,
a gas intake duct connecting the bore of said barrel with the front
end of said tube,
an operating rod slidable in said guiding tube,
said tube having a plunger at its front end and a transverse
coupling groove at its rear end,
a compression spring mounted about said rod and interposed between
said receiver and said plunger,
a carrier slidable in said receiver on longitudinal rigid ways and
having a longitudinal bore to receive the rear end of said
operating rod,
a removable locking slider projecting laterally from said receiver
for locking said operating rod to said carrier,
a lever for holding said slider in locked position,
resilient means constantly urging said lever into slider-holding
position,
a breech bolt rotatable and slidable in said receiver and having
two dogs at its front end which, upon rotation of the bolt in one
direction, engage in a groove in said receiver defined by a step
projecting from the internal surface of said receiver to retain
said bolt locked in closed position,
said carrier having in its bottom a groove with a non-rectilinear
axis which is engaged by said step,
a firing pin slidably housed in an axial bore of said bolt and
having at its rear end an outwardly projecting annular edge,
and a pin mounted transversely in said carrier and positioned to
engage said annular edge,
said operating rod having at its rear end a radially projecting pin
positioned to engage an abutment step formed internally of said
receiver,
said abutment step having a groove longitudinally oriented with
respect to said receiver and disposed to allow sliding motion of
said radially projecting pin therethrough, said radially-projecting
pin being on the same side as said transverse coupling groove at
the rear end of said rod.
2. An automatic rifle comprising a barrel,
a receiver at one end of said barrel,
a guiding tube mounted parallel to said barrel,
a gas intake duct connecting the bore of said barrel with the front
end of said tube,
an operating rod slidable in said guiding tube,
said tube having a plunger at its front end and a transverse
coupling groove at its rear end,
a compression spring mounted about said rod and interposed between
said receiver and said plunger,
a carrier slidable in said receiver on longitudinal rigid ways and
having a longitudinal bore to receive the rear end of said
operating rod,
said carrier having in its bottom a groove with a non-rectilinear
axis which is engaged by said step,
a firing pin slidably housed in an axial bore of said bolt and
having at its rear end an outwardly projecting annular edge,
and a pin mounted transversely in said carrier and positioned to
engage said annular edge,
said carrier having a transverse opening aligned with said
transverse groove of said operating rod and forming a seat for said
locking slider, said locking slider having a front bevel which
facilitates its introduction into said opening, and
said slider having a lateral groove therein,
a lever having a latching tooth which slides in said lateral groove
of said slider and in a groove in said carrier, and
a compression spring constantly urging said latching tooth toward
latching position,
said lever having an external knurled surface for manipulation.
3. An automatic rifle comprising a barrel,
a receiver at one end of said barrel,
a guiding tube mounted parallel to said barrel,
a gas intake duct connecting the bore of said barrel with the front
end of said tube,
an operating rod slidable in said guiding tube,
said tube having a plunger at its front end and a transverse
coupling groove at its rear end,
a compression spring mounted about said rod and interposed between
said receiver and said plunger,
a carrier slidable in said receiver on longitudinal rigid ways and
having a longitudinal bore to receive the rear end of said
operating rod,
a removable locking slider projecting laterally from said receiver
for locking said operating rod to said carrier,
a lever for holding said slider in locked position,
resilient means constantly urging said lever into slider-holding
position,
a breech bolt rotatable and slidable in said receiver and having to
dogs at its front end which, upon rotation of the bolt in one
direction, engage in a groove in said receiver defined by a step
projecting from the internal surface of said receiver to retain
said bolt locked in closed position,
said carrier having in its bottom a groove with a non-rectilinear
axis which is engaged by said step,
a firing pin slidably housed in an axial bore of said bolt and
having at its rear end an outwardly projecting annular edge,
and a pin mounted transversely in said carrier and positioned to
engage said annular edge,
and an aiming device comprising
two lateral plates encompassing the upper portion of said
receiver,
a profiled lever pivoted to rotate in a vertical plane with respect
to said lateral plates and carrying an aiming hole,
a supporting member for said lever mounted rotatably between said
lateral plates and having a plurality of surfaces which are at
different distances from the axis of rotation of said supporting
member,
a spring constantly biasing said profiled lever to rest against
said supporting member, and
a backsight leaf pivoted to said supporting member for grenade
throwing and rotatable between an active and an idle position.
Description
This invention relates to an improved automatic rifle which uses a
portion of the explosion gases to open the receiver.
Automatic rifles are already known, in which a portion of the gases
set free by the explosion is drawn from the barrel and sent to act
upon a plunger-like member which brings the bolt back, causing the
opening of the receiver and the subsequent ejection of the spent
shell, a new cartridge being then automatically loaded into the
receiver block. In such rifles, however, one of the most serious
drawbacks, in general, is that one can never be absolutely sure
that the opening of the receiver occurs only after the fired bullet
has left the barrel, and that the explosion gases may not fire back
against the shooter. In addition, in such prior art approaches, the
mechanical connection between the bolt and the bolt-operating rod
is intricate and the overhauling and reassembling operations, even
for the mere upkeep of the weapon, are time-consuming and
cumbersome.
The principal object of the present invention is to provide, in an
automatic rifle, in which the bolt-cocking operation is performed
by a partial intake of the explosion gases, a simple and reliable
connection between the bolt-operating rod and the carrier which, in
turn, controls the movement of the bolt. Another object is to
provide a connection which permits also the manual actuation of the
bolt to open the receiver.
A further object is to ensure a preselected delay time in the
automatic opening of the receiver immediately after a shot has been
fired.
An additional object of the present invention is to provide a
simple and efficient aiming device for an automatic rifle having
means for a partial intake of the explosion gases.
These objects are achieved by the automatic rifle according to the
invention, of the kind comprising a barrel having an explosion
chamber at one end, which is adapted to be closed by a breech-bolt,
and, at the opposite end, an explosion-gas intake, and which has a
guiding tube mounted parallel, of said barrel and communicating at
its front end with said gas intake, an operating rod slidable in
the interior of said guiding tube and whose rear end has a
transverse coupling groove, a compression spring mounted about said
operating rod and urging the latter against the gas intake port, a
carrier slidable in the receiver on longitudinal rigid ways and
having a longitudinal through-bore adapted to receive the rear end
of the operating rod, a locking-slider adapted rigidly to connect
the operating rod to the carrier, said locking slider projecting
laterally from the receiver and being retained in its locked
position by a resiliently biassed lever, a receiver-bolt slidable
in said breech and having an upwardly projecting pin, said carriage
having in its bottom surface a slot whose axis is not rectilinear,
which is adapted to be engaged by said projecting pin of said bolt,
the later having on its front surface two latching dogs adapted to
engage, by longitudinal sliding movement and subsequent rotation, a
groove formed internally of the front portion of the receiver and
extending through an arcuate portion of the cross-section of the
receiver, and a firing pin housed in an axial through bore of said
bolt, the rear end of the firing pin having a projecting edge
adapted to be engaged by a transversely oriented pin integral with
said carrier.
The outstanding advantage of the structure described above is the
connection between the operating rod and the carrier, which, for
overhauling, only requires that the lever be pressed, the locking
slider withdrawn and the rod rotated through a small arc to
disengage the pin from the groove formed in the receiver.
Another significant advantage of the rifle according to the present
invention lies in that the carrier has now a considerable mass, so
that it behaves like an inertial flywheel and ensures that the
bullet has definitely left the barrel before the bolt may initiate
the receiver-opening motion, irrespective of the so-called "force"
of the propelling charge of the cartridge which has been fired.
Yet another advantage is the simple and sturdy structure of the
several component parts, which ensure a much longer service life of
the rifle.
Other objects and advantages of the present invention will become
more clearly apparent from the ensuing description, given by way of
example only and without limitation, as aided by the accompanying
drawings, wherein:
FIG. 1 is a side-elevational view, partly in cross-section, and
incomplete, of the automatic rifle according to this invention.
FIG. 2 is a cross-sectional view, on an enlarged scale as compared
with FIG. 1, of the mechanical connection between the operating rod
and the carrier-bolt assembly.
FIG. 3 is a plan view, sectioned along the line III--III in FIG.
2.
FIG. 4 is a cross-sectional view taken along the line IV--IV of
FIG. 2.
FIG. 5 is a cross-sectional view taken along the line V--V of FIG.
2.
FIG. 6 is a detail view, fragmentary and in cross-section, taken
along the line VI--VI of FIG. 3.
FIG. 7 is a view, similar to FIG. 3, along the line VII--VII of
FIG. 2, with but the carrier shown in an intermediate stage of the
receiver-opening stroke.
FIG. 8 is a view similar to FIG. 7, in which the carrier-and-bolt
assembly is at the end of the receiver-opening stroke.
FIG. 9 is a cross-sectional view, taken along the line IX--IX of
FIG. 8.
FIG. 10 is a longitudinal cross-sectional view taken along the line
X--X of FIG. 9.
FIGS. 11 and 12 are detail views, in plan and side elevation,
respectively, of an alternative embodiment of the bolt.
FIG. 13 is a front view of the aiming assembly.
FIG. 14 is a side view of the device of FIG. 13, and
FIG. 15 is a partial cross-sectional view taken along the line
XV--XV of FIG. 14.
Having now reference, at the outset, to FIG. 1, the automatic rifle
according to the present invention comprises a barrel 10 which
forms an explosion chamber 11, a receiver 12 carrying the reloading
and firing mechanism, the grip 13, the trigger 14, the automatic
magazine 15 and the aiming assembly 16. The rifle butt is affixed,
in an appropriate manner (not shown) to the receiver 12.
The barrel 10 has, near its front end, a gas-intake port 17,
through which a portion of the explosion gases is drawn.
Parallel to the barrel 10 a guiding tube 18 is mounted thereover,
which communicates, near its own front end, with the gas-intake
port 17. In the interior of the tube 18 is slidably housed a
plunger 19 having a stem 20 and urged by a spring 21 towards the
right as viewed in FIG. 1.
The stem 20 has, at its rear end, a radially projecting pin 22 and
(FIG. 2) has a transverse groove 23. The front portion of the
receiver 12 has a lowermost tapped hole 24 into which the barrel 10
is screwably affixed, and an uppermost bore 25 which offers a seat
to the rear end of the guiding tube 18, which abuts an annular
abutment 26 (see FIG. 10), having a longitudinal groove 27 which is
adapted to allow a sliding motion for the pin 22 during the
insertion of the stem 20 into the receiver. In registry with the
end of the barrel 10, the receiver 12 has an outwardly radially
protruding step 28 which extends along a partial arc along the
receiver section, a longitudinal groove 29 being interposed for a
purpose to be specified hereinafter.
A carrier 31 is housed in the receiver 12 so as to slide along
longitudinal ways 30. The front portion of the carrier 31 has a
hole 32 adapted to receive the rear end of the stem 20, and a
through-opening 33 adapted to match; in transverse alignment, the
opening 23 formed on the stem 20.
To lock the stem 20 to the carriage 31 a locking-slider 34 is
provided, which is adapted to enter the opening 33 and the groove
23 and that has an end which projects laterally outside the
receiver, the latter having, in turn, an elongate hole 12A to allow
the sliding of the slider 34. To facilitate the insertion of the
slider 34 into the opening 33, it has a bevelled end 35, whereas to
latch it (FIG. 6) a notch 36 is provided on the slider 34, so as to
give a seat to a tooth 37 of a lever 38 which slides in a groove
38A, as urged by a compression spring 39 towards the
slider-latching position. As clearly shown in FIG. 6, it suffices,
to set the locking slider 34 free, that the lever 38 be pulled
back, by pushing upon the knurled portion 40 against the bias of
the spring 39.
Through the bottom face 41 of the carriage 31 a groove 42 is
formed, whose axis is not rectilinear and has, instead, the outline
shown in FIG. 3. The groove 42 affords a sliding seat to a pin 44
projecting from the top surface of a bolt 45 having a central
through-bore for housing a firing pin 47: the latter, as the bolt
closes the receiver in the position of FIG. 2, can be driven into
the explosion chamber 11.
The front portion of the bolt 45 has two lateral and diametrically
opposite dogs 48 (FIG. 11) which are adapted to be retained by the
step 28 of the receiver within the groove 49 formed by the step
itself. As shown in FIG. 2, the rear end of the firing pin has a
collar 50 and a bottom abutment 52 and a pin 51 is inserted in the
carrier 31 for a purpose to be clarified hereinafter.
It is appropriate to observe that the longitudinal ways 30 are
terminated in registry with the stp 28 so as to be flush, on one
side, with the longitudinal groove 29 and, on the other side, with
the upper edge of the step 28.
The operation of the rifle is as follows:
Starting from the position of FIG. 2, and assuming that a cartridge
is contained in the explosion chamber 11, by actuating the trigger
14, the firing pin 47 strikes the capsule of the cartridge, so that
the cartridge is fired and thrusts the bullet out of the barrel 10.
Before the bullet leaves the barrel, a portion of the explosion
gases is channeled though the gas intake port 17 and acts on the
plunger 19: the latter is thrust backwards against the bias of the
return spring 21. The operating stem or rod 20 drives the carriage
31 backwards and the latter slides, in correspondence with the
initial rectilinear portion of the groove 42, relative to the bolt
45 and then due to the engagement of the pin 44 with the second,
non aligned portion of the groove 42, causes the bolt to be rotated
about its own longitudinal axis to disengage the teeth 48 from the
step 28 and, more particularly, it brings one tooth to match the
groove 29 of the step and the other tooth to match the portion of
the receiver 12 where the step 28 is lacking. At this stage, both
the carrier and the bolt are in the positions as shown in FIG. 7.
By so doing, the bolt 45 can slide back as controlled by the
carrier 31 and thus the explosion chamber is cleared, and the bolt
effects, in a manner and with the devices as known the conventional
art, the ejection of the spent shell and the automatic loading of
another cartridge, drawn from the magazine 15, into the chamber 11.
At this stage, wherein both the carrier 31 and the bolt 45 are in
the position shown in FIG. 8, the spring 21 thrusts forward the
plunger 19 again and the operating rod 20 therewith. Consequently,
the carrier 31 is driven forward. Inasmuch as the teeth 48 of the
bolt are guided for sliding by the longitudinal ways 30, the return
of the carrier also drives the bolt 45 until the latter is again
with the teeth 48 in the groove 49 as formed by the step 28. At
this stage, due to the sliding motion of the groove 42 relative to
the pin 44, the bolt 45 is rotated about its own longitudinal axis
and locked in the receiver-closing position, in readiness for
firing another cartridge.
On comparing FIGS. 2 and 7, it can be clearly seen that the firing
pin 47 projects frontally from the bolt and is thus in a position
to fire only when the bolt-carrier assembly is closed. Otherwise,
due to the engagement of the pin 51 with it, the assembly is in
retracted position with respect to the bolt and cannot project
ahead of same, any possibility being thus prevented of an
accidental firing before the bolt has thoroughly closed the breech.
Emphasis should also be given to the fact that the groove 42 has a
rectilinear initial portion so that the rotation which is necessary
for clearing the bolt from the step 28 is started with a certain
preselected delay relative to the beginning of the backward motion
of the carrier.
Consequently, one can be assured that the bolt can open the
receiver only when the bullet has left the barrel 10.
It should also be observed that the two ends of the guiding tube
are equal to one another so that the tube can be reassembled
without any special care over the barrel. As a matter of fact, the
holes 53 for venting the explosion gases are formed at both ends of
the tube 18.
In the alternative embodiment shown in FIGS. 11 and 12, the bolt
145 has a pin 144 for cooperating with the groove 142 formed in the
carrier wherein the pin 144 has a polygonal outline, so that,
according to which of the portions of the groove 142 is engaged by
the pin, different surfaces of the pin 144 will be engaged. More
particularly, observing FIG. 11, where the groove 142 has been
shown in dash and dot lines, it can be seen that the groove
comprises a portion 142A and a portion 142B: in the first portion
there will be slidably engaged and thus subjected to forces the two
opposite planar surfaces 144A of the pin 144, whereas the second
portion 142B will engage the opposite surfaces of the pin 144B. By
so doing it is possible, at each carrier stroke, i.e. for each
cartridge fired, to prevent the pin 144 from being stressed over
the same engagement area with the groove 142, the stresses being
conversely distributed around the entire contour of the pin
throughout.
Referring now to FIGS. 13, 14 and 15, the aiming device 16 is
shown, which is a dioptrical sighting device mounted astride the
receiver 12 and comprising two side plates 61 shaped so as to
encompass the top portion of the receiver and to adhere to same. At
a first end, between the plates 61, a pin 62 is mounted, on which,
in an intermediate position between the plates, a lever 63 is
pivotally mounted, which is terminated, at the opposite end of the
aiming device, by a wing 64 having an aiming pinhole 65 formed
therethrough.
As clearly shown in FIG. 14, one of the base sides 66 of the lever
63 is cut so as to receive, by resting thereover, a support 67
which is pivotally mounted between the plates 61 and is an integral
part of a pin 68: the latter is terminated, on the one side, by a
knurled actuating knob 69 and, at the other side, it carries a
resilient locking washer 70 held in position by a plug 71.
Between the two sides 66 and 72 of the lever 63, a pin 73 is
provided, which is integrally affixed to the sides and is acted
upon by the end of a coil spring 74 wound about the pin 68, the
opposite end of the spring engaging the front plate 75 which
interconnects the side plates 61. FIG. 14 clearly shows that the
spring 74 holds the lever 63 against the pin 68 and, more
detailedly, the side 66 thereof against the supporting member 67.
Emphasis should be given to the fact that the supporting member 67
has a polygonal, preferably triangular, cross-sectional outline, in
which the planes of the sides are set at different distances from
the axis of the pin 68. By so doing, according to which face of the
supporting member 67 is the supporting surface for the base side of
the lever 63, the latter is more or less raised with respect to the
pin 68 and thus the effective firing distance range can be varied.
Once the several faces have been calibrated according to the
distances corresponding thereto, the calibration remains unvaried
during the whole service life of the rifle.
The aiming device comprises, in addition, a back-sight leaf 76,
pivoted for rotation about the pin 68 and intended for grenade
throwing. The leaf 76 comprises a front plate 77 having two holes
78 and a notch 81 for aiming, and two side wings, interconnected by
the plate 77, one of said wings having a projection 79 adapted to
engage either recess 80 of the two formed in one of the plates 61
and which serves for retaining the portion 76 in the two positions,
active and inactive, respectively, shown in solid lines and in
dotted lines in FIG. 14.
It remains to emphasize the fact that, with the fastening system
between the operating rod and the carrier-bolt assembly according
to the present invention, the bolt can be made lighter in weight,
whereas a considerably heavier mass can be attributed to the
interconnecting carrier: the latter thus operates like an inertial
flywheel for adjusting the opening of the receiver by the bolt.
As a matter of fact, since the carrier has a considerable mass, it
immediately stores all the power set free by the explosion gases
and yields it evenly for the opening stroke of the bolt, without
the bolt being influenced by the different "force" of the
cartridges being fired.
It should not be overlooked, in addition, that the action of the
gases unfolds itself during an extremely short time and for a
slight fraction of the carrier return stroke, so that the inertia
of the carrier takes a considerable meaning.
It is appropriate to emphasize, lastly, that the sliding ways 30
for the carrier and the bolt dogs are also a reinforcing and
stiffening member for the breech.
The invention has been described in connection with a preferred
embodiment thereof, it being understood, however, that a number of
modifications and changes, ideally and constructionally equivalent
thereto, can be introduced therein without departing from the scope
of this invention.
* * * * *