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Claims  |
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What is claimed is:
1. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means for enabling feeding and firing of the cannon;
and
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including a breech ring having means defining a breech
aperture axially therethrough configured for receiving the breech end of
the barrel; first and second elongate, rigid support members having
forward and rearward ends and intermediate portions therebetween, means
for fixing said intermediate portions to the breech ring in laterally
spaced apart, symmetrical relationship with longitudinal axes of the
members parallel to the barrel bore axis when the barrel is received in
the breech ring; forward support means for rigidly interconnecting the
member forward ends with the barrel when the barrel is received in the
breech ring; means for receiving the bolt means and for guiding
reciprocating movement thereof and means for rigidly interconnecting
rearward ends of the support members, said means for interconnecting
rearward ends of the support members including sear means for enabling
searing up of the bolt means at a rearward position thereof.
2. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means for enabling feeding and firing of the cannon;
said bolt means including a bolt carrier, a bolt, means for slidably
mounting the bolt to the bolt carrier for limited relative axial movement
therebetween and locking means mounted to the bolt for locking the bolt
against axial movement at a forwardmost position during firing of the
cannon;
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including a breech ring having means defining a breech
aperture axially therethrough configured for rotatably receiving the
breech end of the barrel; first and second elongate, hollow rigid support
members having forward and rearward ends; means for fixing the support
members to the breech ring in laterally spaced apart, symmetrical
relationship with longitudinal axes of the members parallel to the barrel
bore axis when the barrel is received in the breech ring; forward barrel
support means for rigidly interconnecting the member forward ends, with
the barrel extending through an aperture formed in said support means when
the barrel is received in the breech ring; means for receiving the bolt
means and for guiding reciprocating movement thereof and means for rigidly
interconnecting rearward ends of the support members; and
(d) barrel gas operated recoil means for causing rearward recoil movement
of the bolt carrier relative to the bolt in response to firing of the
cannon, said recoil means including recoil pistons disposed in the support
members and a barrel gas manifold fixed to the barrel forwardly of the
forward barrel support means, the gas manifold being axially separated
from the forward barrel support means and the support members when the
barrel is received into the breech ring, thereby enabling rotational
installation and removal of the barrel.
3. The open-framework cannon according to claim 2, wherein each of the
first and second support members includes means defining an elongate slot
through a side thereof, said slot extending rearwardly from the breech
ring and facing towards the barrel bore axis, and wherein the recoil
pistons include means for engaging opposite side portions of the bolt
carrier through said elongate slots, the piston and the slots thereby also
forming portions of the means for receiving and guiding the bolt assembly
during reciprocating movement thereof.
4. The open-framework receiver cannon according to claim 3, wherein the
barrel gas manifold includes means defining recoil gas passages
therethrough communicating with passageways defined through sidewalls of
the barrel and means responsive to flow through said passages of
pressurized barrel gas caused by firing of the cannon for driving said
pistons, and hence the bolt carrier connected thereto, rearwardly in
recoil.
5. The open-framework receiver cannon according to claim 4, wherein the
piston driving means includes a pair of actuating elements axially
slidably mounted in the manifold forwardly adjacent to, and axially
aligned with, the recoil pistons, said elements being operative for being
driven rearwardly into driving engagement with the recoil pistons by
pressurized barrel gas flowing through said recoil gas passages after
firing of the cannon and being recessed forwardly into the manifold at all
other times.
6. The open-framework receiver cannon according to claim 5, wherein the
weapons system shell feed means includes a gas operated shell feeder,
wherein the barrel gas manifold includes means defining a feeder gas
passage communicating with a gas passage defined through a sidewall of the
barrel; and including means for supplying pressurized barrel gas from the
manifold feeder gas passage to the forward barrel support and thence to
the shell feeder for operation thereof in response to firing of the
cannon, said shell feeder gas supplying means including an actuating
element axially slidably mounted in the manifold, said element being
operative for being driven rearwardly into engagement with the forward
barrel support by pressurized barrel gas flowing through said feeder gas
passage after firing of the cannon and being recessed forwardly into the
manifold at all other times.
7. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means operative for feeding and firing of the
cannon; said bolt means including a bolt carrier, a bolt, means for
slidably mounting the bolt to the bolt carrier for limited relative axial
movement therebetween and locking means mounted to the bolt for locking
the bolt at a forwardmost position during firing of the cannon, the bolt
carrier having portions configured for interfering with the locking means
to prevent unlocking of the bolt when the bolt carrier is at a forward
position;
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including a breech ring having means defining a breech
aperture axially therethrough configured for receiving the breech end of
the barrel; first and second elongate, hollow rigid support members having
forward and rearward ends and intermediate portions therebetween, means
for fixing said intermediate portions to the breech ring in laterally
spaced apart, symmetrical relationship with longitudinal axes of the
members parallel to and coplanar with the barrel bore axis when the barrel
is received in the breech ring; barrel support means for rigidly
interconnecting the member forward ends with the barrel when the barrel is
received in the breech ring; means for receiving the bolt means and for
guiding reciprocating movement thereof and means for rigidly
interconnecting rearward ends of the support members;
(d) sear means responsive to the weapons system triggering means for
searing up the bolt assembly at a position relatively adjacent to the
means interconnecting rearward ends of the support members;
(e) recoil means disposed in the support members for causing rearward
recoil movement of the bolt carrier relative to the bolt in response to
firing of the cannon to thereby move said bolt carrier interfering
portions out of interference with the bolt locking means to enable
unlocking of the bolt; and
(f) drive means disposed inside the support members and connected to said
bolt means for driving the bolt means, upon unsearing thereof, forwardly
towards the breech ring,
said drive means including a pair of elongate coil springs and spring
guides releasably disposed in the support members and extending forwardly
from the rearward ends of the support members for substantially the entire
length thereof, forward ends of the springs being in engaging relationship
with corresponding portions of the recoil means.
8. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means for causing feeding and firing of the cannon;
and
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including a breech ring having means defining a breech
aperture axially therethrough configured for receiving the breech end of
the barrel; first and second elongate, rigid support members having
forward and rearward ends; means for fixing the support members to the
breech ring in laterally spaced apart, symmetrical relationship with
longitudinal axis of the members parallel to, and coplanar with, the
barrel bore axis when the barrel is received in the breech ring, barrel
support means for rigidly interconnecting the member forward ends with the
barrel when the barrel is received in the breech ring; means for rigidly
interconnecting rearward ends of the support members and means for
receiving the bolt means and for guiding reciprocating movement thereof,
said means for receiving and guiding the bolt means including a plate
longitudinally extending between the breech ring and the means for rigidly
interconnecting rearward ends of the support members and disposed below
the barrel bore axis, said plate including bolt means engaging tracks and
means defining an axially elongated ejection port for enabling fired shell
casings to be ejected downwardly therethrough.
9. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means for feeding and firing the cannon; and
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including, a breech ring having means defining a breech
aperture axially therethrough configured for receiving the breech end of
the barrel; first and second elongate, rigid support members having
forward and rearward ends; means for fixing the support members to the
breech ring in laterally spaced apart, symmetrical relationship with
longitudinal axes of the members parallel to, and coplanar with, the
barrel bore axis when the barrel is received in the breech ring; barrel
support means for rigidly interconnecting the member forward ends when the
barrel is received in the breech; means for receiving the bolt means and
for guiding reciprocating movement thereof; means for rigidly
interconnecting rearward ends of the members and means for compliently
mounting the cannon to the cannon mount means for limited axial cannon
recoil and counter recoil movement relative thereto;
said means for compliently mounting the cannon to the cannon mount means
including first and second rigid, tubular recoil cylinders disposed around
portions of the first and second support members, respectively,
intermediate the breech ring and the barrel support means, and including
axially compressable recoil spring means disposed between the recoil
cylinder members and the respective support members and providing
interconnections therebetween, said recoil spring means opposing relative
axial movement between the recoil cylinders and the support members in
both axial directions.
10. The open-framework receiver cannon according to claim 9, wherein the
means for compliently mounting the cannon to the cannon mount means
includes outwardly projecting lugs formed on the first and second recoil
cylinders and fasteners for releasably fastening the lugs to said cannon
mount means, said lugs being formed symmetrically about the barrel bore
axis and coplanar therewith.
11. In an automatic cannon weapons system having shell feed means,
triggering means and cannon mount means having laterally spaced apart
first and second cannon mounting tracks, an open-framework receiver
cannon, which comprises:
(a) a cannon barrel having a shell receiving, breech end and a barrel bore
axis;
(b) reciprocating bolt means for feeding and firing the cannon; and
(c) means for supporting the barrel and bolt means in operative
relationship with the shell feed means and triggering means, said
supporting means including a breech ring having means defining a breech
aperture formed axially therethrough configured for receiving the breech
end of the barrel; first and second elongate, rigid support members having
forward and rearward ends; means for fixing the support members to the
breech ring in laterally spaced apart, symmetrical relationship with
longitudinal axis of the members parallel to, and coplanar with, the
barrel bore axis when the barrel is received in the breech ring; barrel
support means for rigidly interconnecting the member forward ends with the
barrel when the barrel is received in the breech ring; means for receiving
the bolt means and for guiding reciprocating movement thereof and means
for rigidly interconnecting rearward ends of the support members, said
breech ring, barrel support means and means for rigidly interconnecting
rearward ends of the support members each including means for slidably
engaging said tracks, to thereby limit recoil and counterrecoil movement
of the cannon relative to the cannon mount means to movement along side
tracks.
12. The open-framework cannon according to claim 11, wherein said means for
slidably engaging the tracks include track engaging transverse pairs of
lugs formed symmetrically about the barrel bore axis and coplanar
therewith. |
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Claims |
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Description |
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The present invention relates to the field of automatic guns, and more
particularly to receiver portions of automatic cannon.
Gas operated automatic cannon and the like have heretofore been constructed
with comparatively large and massive receivers. In these receivers are
typically installed or "received" such parts of the gun as a reciprocating
bolt and bolt carrier assembly, bolt carrier recoil mechanism, a bolt
recoil buffer, a shell casing ejector, a sear and portions of triggering
apparatus. As such, the receivers function to maintain the received parts
in a predetermined spatial arrangement and to provide tracks, slots and so
forth for guiding movement of parts during firing. Although mechanical and
environmental protection for the received parts is also provided by the
receiver, such protection is usually unnecessary, since receiver portions
of the cannon are ordinarily mounted in enclosures, for example, turrets,
support cradles, or aircraft weapons pods.
Because complex internal configuration is necessary to accommodate and
guide movement of the received parts, receivers are ordinarily the most
difficult and time consuming, and accordingly the most expensive, part of
the cannon to construct. In addition, costly manufacturing equipment is
required, as are skilled manufacturing personnel. As a result of this
internal complexity, receivers for some types of large automatic guns
must, as an example, be constructed of two separately machined half
sections. After machining of the half sections, and after considerable
jigging and clamping, the half sections are welded together to complete
the receiver. Long lead times are routinely required for constructing
receivers of all types; consequently, final assembly of otherwise finished
automatic cannon is often considerably delayed awaiting completion of the
receivers.
Furthermore, due to heavy, box-like construction, gun receivers are usually
one of the heaviest parts, if not the heaviest part, of the gun.
Frequently, receiver portions weigh two or three times as much as the
associated gun barrel. As an illustration, typical 35 mm automatic cannon
have heretofore had a barrel weight of about 300 pounds and a receiver
weight of about 800 pounds.
Although some advantages may be associated with comparatively massive
receivers--barrel recoil is generally reduced as are gun mount reaction
forces--massive receivers are generally disadvantageous. Cannon having
large and massive receivers are difficult to handle and to transport, and
are not well suited to most airborne applications. In the field, where
availability of repair equipment is limited, because heavy receivers of
large automatic cannon are difficult to handle, gun repairs are time
consuming. Routine preventive maintenance, such as inspection, cleaning
and greasing, is also neglected, reliability being thereby affected.
Automatic cannon with massive receivers have limited usefulness not only in
airborne applications, but also in mobile applications in which cannon
carrying vehicle speed, range and maneuverability are important. Even if
having a massive receiver may not preclude use of a particular type of
cannon in such applications, the weight of ammunition that can be carried
is correspondingly reduced with weapon system effectiveness being
adversely affected.
A further disadvantage of massive cannon receivers is apparent in uses in
which the cannon are mounted to rotatable turrets or platforms. In such
applications, rapid, precise movement of the turrets or platforms to track
fast moving targets, such as attacking aircraft, is made more difficult;
that is, because of high cannon inertia, rapid acceleration and
deceleration of the turrets or platforms during target tracking is
difficult to achieve and control precisely. To offset this, greater
auxillary power and heavier drive systems must usually be provided for
heavy guns than for light guns, thereby further increasing mass of the
entire weapon system.
Also associated with most heretofore available large automatic cannon,
often a result of trying to minimize receiver size and weight, are
non-symmetrical bolt carrier recoil and drive apparatus. Typically, one or
two recoil cylinders, disposed below the barrel axis, are used to contain
apparatus which impart recoil to the bolt carrier after firing to enable
unlocking of the bolt from the breech, and for driving the bolt carrier
and bolt forwardly from the sear when firing is initiated. As a result,
firing transmits eccentric forces to the cannon barrel and causes whipping
thereof. Such barrel whipping increases dispersion of fired projectiles,
particularly at high firing rates which not not permit the whipping to be
fully damped out between shots.
Other, less conventional automatic cannon, such as multi-barreled,
Galting-gun types and multi-chambered, revolver types, since an axially
reciprocating bolt assembly principle is not utilized, may have less
complex receiver or breech end portions. However, such cannon have various
other disadvantages, such as being otherwise more complex to manufacture,
being also relatively massive and usually requiring external barrel or
cylinder drives. Thus, these types of cannon have not replaced
conventional, bolt actuated gas operated cannon in most ground based
applications, in particular those applications requiring relatively large
calibre cannon, for example, calibres of 35 mm and larger, as used in
anti-aircraft weapons systems.
Because of these and other deficiencies and disadvantages associated with
large and massive receivers of most modern, gas operated automatic cannon,
applicant has invented an open-framework receiver, or substantially
receiverless, gas operated automatic cannon, which is accordingly much
less massive and much less costly and time consuming to manufacture than
comparable conventional cannon, and which can be constructed without use
of the special equipment and skills required for manufacturing
conventional cannon receivers.
In an automatic cannon weapons system having shell feed means, triggering
means and cannon mount means, an open-framework receiver cannon, according
to the present invention, comprises a cannon barrel having a shell
receiving breech end and a barrel box axis, reciprocating bolt means for
enabling firing of the cannon and means for supporting the barrel and bolt
means in operative relationship with the shell feed means and triggering
means.
Included in the supporting means are a breech ring having a breech aperture
formed axially therethrough configured for receiving the breech end of the
barrel, first and second elongate, rigid support members having forward
and rearward ends and intermediate portions therebetween and means for
fixing the support member intermediate portions to the breech ring in
laterally spaced apart, symmetrical relationship with longitudinal axis of
the members parallel to, and coplanar with, the barrel bore axes when the
barrel is received in the breech ring. Barrel support means are also
included in the supporting means for rigidly interconnecting the member
forward ends with the breech ring received barrel, as are means for
receiving the bolt means and for guiding reciprocating movement thereof
and means for rigidly interconnecting rearward ends of the support means.
More specifically, the means for interconnecting rearward ends of the
support members includes buffer means for stopping recoil of the bolt
means after firing of the cannon and for imparting counterrecoil to the
bolt means immediately thereafter. A buffer and a buffer housing are
included in the buffer means, as are means for detachably connecting the
buffer housing to the support member rearward ends to provide rigid
interconnection thereof. The support members each comprise an elongate,
hollow cylinder having an elongate slot extending rearwardly, upon
assembly, from the breech ring and facing the barrel bore axis.
The bolt means includes a bolt carrier, a bolt, means for slidably mounting
the bolt to the bolt carrier for limited relative axial movement
therebetween and locking means mounted to the bolt for causing locking of
the bolt to the breech ring during firing of the cannon. Portions of the
bolt carrier are configured for interfering with the locking means to
prevent unlocking of the bolt from the breech ring when the bolt carrier
is at a forwardmost position relative to the bolt, as is the condition at
the instant of firing.
Recoil means are provided for causing rearward recoil movement of the bolt
carrier, relative to the bolt, in response to firing of the cannon,
thereby moving the bolt carrier out of interference with the bolt locking
means to enable unlocking of the bolt from the breech ring. Comprising the
recoil means are recoil pistons disposed in each of the support members.
The recoil pistons include means for engaging opposite side portions of
the bolt carrier through the support member slots, the pistons and slots
thereby also forming portions of the means for receiving and guiding the
bolt assembly during reciprocating movement thereof. Also included in the
bolt carrier recoil means is a barrel gas manifold, fixed to the cannon
barrel forwardly of the barrel support means, having gas passages aligned
with gas apertures formed through the barrel and means responsive, after
firing of the cannon, to flow of pressurized barrel gas through the
passages, for driving the pistons and the bolt carrier connected thereto
rearwardly in recoil.
The barrel gas manifold also includes a feeder gas passage communicating
with an aperture through the barrel means for routing pressurized barrel
gas from a manifold feeder gas port to a gas operated shell feeder.
To drive the bolt assembly forwardly from a seared up position, drive means
disposed in the support members are connected to the recoil pistons and
include a pair of elongate coil springs and spring guides extending
forwardly from the rearward ends of the support members for substantially
the entire length thereof. Forward ends of the springs are in engaging
relationship with forward portions of the recoil pistons.
A plate longitudinally extending between the breech ring and the buffer
housing, below the barrel bore axis, includes bolt means engaging tracks
and an axially elongated ejection port for enabling fired shell casings to
be ejected downwardly through the plate.
Compliant mounting of the cannon to cannon mounting means, for limited
axial cannon recoil and counterrecoil movement, is provided by first and
second rigid, elongate, hollow recoil cylinders disposed around portions
of the first and second support members, respectively, between the breech
ring and the barrel support means. Such recoil cylinders have outwardly
projecting lugs formed symmetrically about the barrel bore axis and
coplanar therewith; mounting of the cannon to the cannon mounting means is
by fasteners which pass through recesses in these lugs. Axially
compressible recoil spring means are disposed between the recoil cylinders
and the respective support member cylinders and provide interconnections
therebetween, the spring means opposing relative movement between the
recoil cylinders and the support members in both axial directions.
The cannon mounting means preferably includes laterally spaced apart, first
and second mounting tracks into which the recoil cylinder lugs and
corresponding portions of the breech ring, the barrel support means and
the buffer are axially slidably received, recoil and counterrecoil
movement of the cannon relative to the cannon mounting means being thereby
limited to movement along the tracks.
A better understanding of the present invention may be had from a
consideration of the following detailed description, taken in conjunction
with the accompanying drawings, in which:
FIG. 1 is a perspective drawing of an open-framework receiver automatic
cannon, according to the present invention;
FIG. 2 is a partially cutaway perspective drawing of rearward portions of
the open-framework receiver cannon of FIG. 1, showing a pair of support
members, a breech ring, a bolt assembly and a recoil buffer;
FIG. 3 is a plan view showing major portions of the open-framework receiver
cannon of FIG. 1 in exploded form;
FIG. 4 is a longitudinal, vertical sectional view along line 4--4 of FIG.
2, showing features of the open-framework receiver cannon;
FIG. 5 is a transverse, vertical sectional view along line 5--5 of FIG. 2,
showing means for mounting and guiding the bolt assembly;
FIG. 6 is a partial horizontal sectional view, showing rearward portions of
the open-framework receiver cannon;
FIG. 7 is a partial horizontal section view, generally along line 7--7 of
FIG. 1, FIG. 7(a) showing portions of the breech ring and intermediate
portions of the support members, and FIG. 7(b) showing forward ends of the
support members and interconnection thereof;
FIG. 8 is a perspective drawing, showing, by way of example, means for
mounting the open-framework receiver cannon to a cannon mounting cradle
associated with a weapons system;
FIG. 9 is a horizontal sectional view along line 9--9 of FIG. 8, showing
releasable mounting of the cannon to the mounting cradle;
FIG. 10 is a vertical sectional view along line 10--10 of FIG. 8, showing
slidable mounting of the cannon in the cradle; and
FIG. 11 is a horizontal sectional view similar to FIG. 7, FIG. 11(a)
showing, after firing, full recoil of the cannon relative to the cannon
mount, and FIG. 11(b) showing subsequent full counterrecoil of the cannon
relative to the cannon mount.
Seen assembled in FIGS. 1 and 2, is an open-framework receiver, gas
operated cannon 10 according to the present invention. Because of the open
configuration of rearward cannon portions, as compared to corresponding
closed receivers of conventional gas operated cannon, the cannon 10 may be
considered to be a "receiverless" cannon, the below described relatively
light weight but rigid open-framework taking the place of a conventional
massive receiver.
In general, the cannon 10 comprises a barrel 12, first and second elongated
rigid tubular support members 14 and 16, respectively, a recoil buffer
assembly 18, a breech ring 20 and a forward barrel support assembly 22.
Also included are a barrel mounted gas manifold assembly 24, a
reciprocating bolt means or assembly 26, first and second cannon recoil
and mounting assemblies 28 and 30, respectively, and a generally
rectangular bottom plate 32.
As more particularly described below, intermediate portions of the support
members 14 and 16 are fixed to the breech ring 20 which receives a breech
or firing chamber end of the barrel 12. Forward ends of the support
members 14 and 16 are interconnected with one another and the barrel 12 by
the barrel support 22. The buffer assembly 18 rigidly interconnects
rearward ends of the support members 14 and 16.
Mounting of the bolt assembly 26, and guiding thereof in recoil and
counterrecoil travel between the breech ring 20 and the recoil buffer 18,
is provided by the support members 14 and 16 and the bottom plate 32.
Means, described below, are disposed within the support members 14 and 16
for causing recoil of portions of the bolt assembly 26 after firing of the
cannon. Also disposed internally of the support members 14 and 16 are
drive means 40 for driving the bolt assembly 26 forwardly upon release
from sear means 42 connected to the buffer 18, in response to conventional
triggering means (not shown) associated with a weapons system (also not
shown) with which the cannon 10 is used.
More particularly, as seen in the exploded drawing of FIG. 3, a
symmetrical, rigid open-framework assembly 44, which may also be
considered as a breech ring assembly, includes the breech ring 20, the
first and second support members 14 and 16 and the forward barrel support
22. Included in the framework assembly 44 are the first and second cannon
recoil and mounting assemblies 28 and 30, which are disposed around
corresponding ones of the support members 14 and 16 between the breech
ring 20 and the barrel support 22. Also included are bolt carrier recoil
means 46, only bolt assembly engaging portions of which are visable in
FIG. 3, mounted within each of the support members 14 and 16.
In order to accommodate the bolt assembly drive means 40 and the recoil
means 46, the support members 14 andd 16 are formed as long hollow,
preferably steel, cylinders. As an illustration, for a 35 mm cannon, the
members 14 and 16 may be about 51/2 feet long and 1 11/16 inches nominal
outside diameter. Construction of the support members 14 and 16 is thus
comparatively simple without requiring complex machinery or a high degree
of skill. For example, the support members 14 and 16 can readily be
fabricated on the same type of conventional barrel turning machinery used
for making the barrel 12.
Fixing of the support members 14 and 16 to the breech ring 20 is by
laterally spaced apart, first and second apertures 48 and 50 formed
longitudinally through opposite sides of the breech ring and into which
intermediate portions of the support members are received. The apertures
48 and 50 are oriented so that when the support members 14 and 16 are
installed therethrough, longitudinal axis of the members are parallel to,
and spaced symmetrically to opposite sides of, a longitudinal framework
assembly axis which coincides, on assembly, with a barrel bore axis 52. In
addition, and importantly, the breech ring apertures 48 and 50 are
positioned so that, longitudinal axes of the received support members 14
and 16 are coplanar with the barrel bore axis 52.
Because longitudinal axes of the support members 14 and 16 are located
symmetrically about, and coplanar with, the barrel bore axis 52, loads on
the assembled cannon 10, for example, firing reaction forces through the
recoil and mounting assemblies 28 and 30 and bolt carrier recoil forces
caused by the recoil means 46, are symmetrically applied to the cannon and
are in the plane of the bore axis 52. As a result, offset or eccentric
loading on the cannon 10, which could cause whipping of the barrel 12, is
virtually non-existant. Projectile dispersion during firing is thus very
small, making the cannon 10 highly accurate, as is very important in
critical weapons systems, such as anti-aircraft gun systems.
Because of this symmetry about a vertical plane through the bore axis 52,
generally only one side of the cannon 10 is described herein, symmetrical
and mirror image features and elements being given identical reference
numbers. An exception is made to this practice where separate
identification of symmetrical or mirror image features or elements is
provided to enable clearer description of the invention.
Typical of the members 14 and 16, the first support member 14 is axially
retained in the breech ring aperture 48 by a generally annular ring or
boss 58 formed around the outside of the member (except for bore axis
facing regions), the boss forwardly abutting a breech ring rear face 60. A
cooperating nut 62, when threaded onto a corresponding exteriorally
threaded portion (not shown in FIG. 3) of the member 14, rearwardly abuts
a breech ring forward face 64.
Predetermined rotational orientation of the support member 14 in the breech
ring aperture 48, is provided by a breech ring mounted key 66 partially
received into a corresponding support member slot 68. A pin 70 is used to
retain the key 66 in such installed position. The second support member 16
is retained in the corresponding breech ring aperture 50 in an identical
manner.
Rearward ends of the support members 14 and 16 are rigidly interconnected
by the buffer assembly 18, which includes a structural buffer housing 78
within which is disposed a buffer 80 (FIG. 2). For the particular type of
buffer assembly 18 illustrated, the sear means 42 is pivotally mounted to
a forwardly projecting buffer portion 82, so the buffer assembly also
functions as a sear buffer. That is, the buffer assembly 18 performs a
first function of stopping recoil of the bolt assembly 26 and imparting
counter-recoil thereto after firing of the cannon 10 and a second function
of buffering or softening searing up of the bolt assembly when firing is
interrupted.
To perform these dual functions, the buffer 80 may utilize mechanical
springs to absorb and release recoil and searing kinetic energy and may be
of generally conventional mechanical construction. Alternatively, the
entire buffer assembly 18 may be of the gas "spring" type described in
copending U.S. patent application Ser. No. 024,185, filed on even date
herewith.
Releasable connection of the buffer assembly 18 to rearward ends of the
support members 14 and 16 is enabled by a two support member receiving
apertures 86 (only one of which is shown) formed through opposite sides of
the housing 78, parallel to, and in a common plane with, the bore axes 52.
After installation onto the support members 14 and 16, the buffer assembly
18 is retained thereon by two locking pins 88 (FIG. 2) installed
downwardly through pin apertures 90 (positioned to intersect the
longitudinal housing apertures 86) into corresponding apertures 92 formed
through the support members 14 and 16. Spring loaded detent means (not
shown) releasably retain the pins 88 in the apertures 90 and 92.
However, prior to installing the buffer assembly 18 onto the support
members 14 and 16 in such manner, the bottom plate 32 and bolt assembly 26
are installed, as described below. Interconnection of forward ends of the
members 14 and 16, by the barrel support 22, is also described below, in
conjunction with description of the recoil and mounting means 28 and 30.
Formed in a generally conventional manner, the barrel 12, to which the gas
manifold 24 is fixed, includes several (for example, five)
circumferentially spaced apart breech ring mounting lugs 94 which
outwardly project from a breech end portion 96. An uppermost one of the
mounting lugs 94 is formed having an axially extending detent slot 98
enabling rotational locking of the barrel 12 to the breech ring 20 by a
detent pin 100 (FIG. 2).
To receive the barrel 12, the breech ring 20 is formed having an axial
aperture 108, around forward regions of which are a plurality of inwardly
projecting lugs 110 corresponding to the barrel lugs 94, width of spacings
or slots 112 between the breech ring lugs being slightly greater than
width of the barrel lugs. To mount the barrel 12 to the breech ring 20,
the barrel is oriented with the barrel lugs 94 aligned with the slots 112.
Then, the barrel 12 is pushed rearwardly and rotated to position the
barrel lugs 94 directly rearwardly of the breech ring lugs 110, subsequent
direct forward removal of the barrel from the breech ring being prevented
by interference between the lugs and by the detent pin 100 which prevents
turning the barrel to realign the lugs 94 with the slots 112.
Alternatively, connection of the barrel 12 to the breech ring 20 may be by
conventional interrupted threads (not shown) formed on the barrel and in
the breech ring.
An annular boss or enlarged diameter region 114 is formed on the barrel 12
immediately rearwardly of the gas manifold position for mounting of the
barrel support 22. Forwardly of the gas manifold position, the outside of
the barrel 12 is threaded, in a region 116, for receiving a large threaded
retaining ring 118. Detachably connected to the muzzle end of the barrel
12 is a muzzle brake 120 (FIG. 1), which may be of conventional
configuration.
An open rearward region 122 of the breech ring 20 is configured for
receiving forward portions of the bolt assembly 26 when the bolt assembly
is in a forwardmost, battery position. Breech ring side recesses 128
enable locking of the bolt assembly 26 to the breech ring 20 during firing
of the cannon 10, as described below. A lower portion 130 of the breech
ring region 122 is configured for receiving forward end portions of the
plate 32 (FIG. 4) which provides lower support and axial guiding of the
bolt assembly 26.
Elongate bolt assembly guide recesses or tracks 130 (FIG. 5) are formed
longitudinally along raised sides 132 of the plate 32. In a flat,
transverse bottom portion 134 of the plate 32, an axially elongated port
136 is formed, through which casings 138 of fired shells are automatically
ejected (FIG. 4) during operation. As also seen in FIG. 4, a depending
rearward end portion 142 of the bottom plate 32 is configured for abutting
a mating portion 146 which projects slightly forwardly, in plate engaging
relationship, from the buffer housing 78.
Particular configuration of the bolt assembly 26 may vary according to
specific requirements of the cannon 10. For illustrative purposes,
however, the bolt assembly 26 is shown and described as the type disclosed
in U.S. patent application, Ser. No. 024,188, filed on even date herewith.
As such, the bolt assembly 26 comprises a generally T-shaped bolt carrier
152, an L-shaped bolt 154 and two opposing bolt locking lugs 156 having
rearward ends pivotally mounted to the bolt (FIG. 7a).
An inverted, T-shaped projection 158 (FIG. 5) formed longitudinally along
bottom portions of the bolt carrier 152, and a mating slot 160 formed in
rearward portions of the bolt 154, enable mounting of the bolt and bolt
carrier together for limited axial sliding movement therebetween.
Outwardly projecting lugs 162 on opposite, lower sides of the bolt 154
engage, on assembly, the bottom plate tracks 130, thereby constraining the
bolt assembly 26 to the plate 32 while guiding bolt assembly recoil and
counterrecoil movement between the breech ring 20 and the buffer assembly
18.
Opposing inner surfaces 164 of the bottom plate sides 132 keep the locking
lugs 156 in a retracted condition unless the bolt assembly 26 is forward
at the breech ring 20, at which position the bottom plate sides terminate.
During firing, when the bolt assembly 26 reaches the breech ring 20, a
nose portion 166 (FIG. 7a) of the bolt carrier 152 causes the locking lugs
156 mounted on the stopped bolt 154 to pivot outwardly into locking
engagement with the breech ring recesses 128 in a generally conventional
manner. Then, as bolt carrier forward movement continues to cause firing
of a chambered shell by a bolt carrier mounted firing pin (not shown), an
interfering bolt carrier portion 172 slides between the extended locking
lugs 156 to prevent their retracting from the breech ring recesses 128.
After firing, the bolt carrier 152 is rearwardly recoiled relative to the
bolt 154, by the recoil means 46, out of interference with the locking
lugs 156 to enable bolt unlocking and recoil. Sidewardly projecting bolt
carrier arms 174 mechanically engage corresponding bolt carrier connecting
portions 176 of the recoil means 46 (FIG. 5), through elongate, inwardly
facing slots 178 in the members 14 and 16 rearwardly of the breech ring
20, to enable such bolt carrier recoiling after firing, as more
particularly described below.
Included on each of the bolt carrier arms 174 is a depending lug 180
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