 |
Description  |
|
|
BACKGROUND OF THE INVENTION
Heretofore in self-loading and automatic or semiautomatic firearms designed
to fire high-powered ammunition it has been necessary to utilize a
mechanically locked breech. Such systems are present in most gas or recoil
operated firearms and require somewhat complicated breech and locking
mechanisms in which the tolerances of the various components are critical.
Not only are such weapons more difficult and expensive to manufacture but
because of the close tolerances wear on the parts and subsequent
replacement is often required. In addition, because of the multiplicity of
the components, such weapons are quite heavy and thus somewhat burdensome
for an operator to carry and handle.
A number of simplified self-loading and automatic or semi-automatic weapons
have been proposed in attempts to obviate the disadvantages of
mechanically locked breech operated weapons known as blowback firearms,
which because of their ease of maintenance, relatively few parts and lower
cost, have been used extensively for military purposes. However, such
weapons have necessitated the use of relatively low-powered ammunition
since the gas expanding in the firing chamber cannot reach great enough
pressure before the action of the rearward moving breech results in
significant pressure drop in the firing chamber. Accordingly, the velocity
of the bullets fired from such weapons is relatively low and concomitantly
the accuracy is significantly impaired by the heavy breech block being in
motion compared to weapons incorporating mechanically locked breeches.
In an attempt to overcome this problem, mechanically delayed blowback
weapons have been proposed which incorporate roller locks or similar
devices. However, such weapons have proven extremely expensive to
manufacture because of very close tolerances required in the action as
well the complicated multi-piece breech blocks needed for the delay
system. Gas operated blowback devices for damping or delaying recoil of
the breech or bolt have been proposed, for example, in U.S. Pat. Nos.
1,834,021 and 3,261,264. However, such devices do not provide for adequate
damping of the breech block or bolt during the delayed recoil. Moreover,
these prior art devices do not adequately provide for venting of the hot
gases from the locking chamber. Unless these gases are adequately removed,
the weapon may soon overheat to an extent of malfunction as well as
causing possible permanent deterioration of the components involved.
SUMMARY OF THE INVENTION
It is an object of the present invention to obviate the above-noted
disadvantages by incorporating a blowback action in which the bolt is
temporarily locked in its forward position immediately after firing and
until the bullet has left the barrel. It is also an object of the
invention to provide for a gas breech or bolt locking system in a blowback
action device in which a vented locking chamber yields improved regulation
of the cyclic rate. It is also an object to provide a weapon having an
improved design whereby the malfunction and deterioration of the
components of the blowback and gas locking operation are minimized.
Utilizing such a concept, high powered ammunition can be fired without the
necessity of incorporating mechanically locked breeches or the requirement
of unduly heavy bolts or close tolerance parts. These as well as other
advantages will be evident from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional elevation illustrating the components and features of
the gas locking blowback weapon of the invention at the instant of firing
a cartridge in the chamber;
FIG. 2 is a sectional elevation of the components of FIG. 1 after the shell
has left the weapon and at the termination of bolt recoil; and
FIG. 3 is a section taken along line A--A of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, the invention illustrating a gas lock blowback
operation. The components are shown with a cartridge in the firing chamber
at the moment when the firing pin of a forwardly moving bolt 1 strikes the
cartridge. Bolt 1 has a fixed firing pin 2 on the forward surface thereof,
and a forwardly extending arm 3 and plate 4. Barrel housing 16 includes
shoulder 6 at the upper back portion and which extends into gas locking
chamber 7 at its rearward end with forward shoulder surface 9 defining the
back of the gas locking chamber. Barrel housing 16 may or may not be
constructed as an integral part of the barrel so that they may be cast in
one-piece construction rather than separately as shown. As illustrated in
FIG. 3, barrel housing 16 is provided with a slot 20 extending along its
top surface and a pair of rims 15 having interior slanted surfaces to form
a wedge shaped slot for slidably receiving arm 3 of bolt 1. The slot
extends along the shoulder and may also be provided on the forward barrel
housing, i.e., forward of the gas locking chamber so that the bolt arm may
be received therein substantially or entirely along its length. The bolt
arm is, of course, shaped to slidably fit into the slot. The purpose for
this feature is to prevent bolt arm 3 from being driven upwardly against
receiver 27 when the gases are vented into the locking chamber 7 as will
be more fully discussed hereinafter. Instead of the wedge or slanted
opposing interior surfaces of rims 15 and arm 3, the slot may have, for
example, a flattened rectangular shape or the like defined between rims
which extend upwardly and inwardly with the bolt arm having the same cross
sectional shape of the slot and with the rims extending at least partially
over the bolt arm to prevent its upward movement. Without such a feature,
the bolt arm could be driven upwardly becoming warped and impinging on the
receiver. Any equivalent means for achieving the same advantage may be
used. The receiver is shown schematically for illustration only. For
example, there will normally be no substantial spacing between the upper
arm surface and the receiver in order to reduce the size and bulkiness of
the weapon. The shape of the receiver may also be any varied or modified
design as desired. Moreover, there will be means, not shown, for securing
the components within the receiver.
The bolt arm 3 is also provided with a vented plate 4. This member has a
vent 17 extending entirely therethrough and a lip 14 extending forwardly
from the plate. A groove or cavity 22 is formed on the forward portion of
the vented plate. Extending across the cavity is a cross pin 13 secured to
the receiver or barrel housing and received and seated in the cavity so
that lip 14 underlies and engages the pin when the plate and bolt are in
the forwardmost position shown in FIG. 1. This feature provides additional
means for preventing the bolt arm from being forced upwardly when gas
expands rapidly in the locking chamber 7. The purpose of vent 17 is to
allow gas in the locking chamber to bleed or slowly pass through the vent
at the end of the firing cycle as shown in FIG. 3.
The barrel is provided with a gas port 8 which communicates with the barrel
interior and locking chamber 7 defined between the forward extending bolt
arm 3, the upper exterior barrel surface, and between the forward surface
9 of shoulder 6 and rear surface 10 of plate 4. Port 8 is preferably
located immediately forward of the cartridge, i.e., more than one
cartridge length but less than 2 cartridge lengths from the end of the
firing chamber. The close proximity of the port to the cartridge or firing
chamber end is to provide for entry of gas from the fired cartridge
through the port and into the gas locking chamber 7 as soon as possible.
In operation, a cartridge located in firing chamber 11 will be fired when
firing pin 2 of bolt 1 strikes the head of the cartridge case in response
to trigger pull which releases the bolt from the rearward position. As the
bolt moves forward, arm 3 advances and slides along slot 20 on barrel
shoulder 6. The bolt position shown in FIG. 1 is in the forward position
as it strikes a cartridge during the firing cycle and at the same time lip
14 on plate 4 locks under cross pin 13 in order to prevent upward movement
of arm 3 during peak gas pressure. On firing, the bolt will tend to be
forced rearwardly by the cartridge case, opening the breech, which
immediately after firing would be premature. However, there will be
sufficient initial delay of the bolt rearward movement due to its weight
as well as recoil spring 12 urging the bolt in its forward position until
the bullet has cleared gas port 8. Gas from the exploded cartridge charge
enters locking chamber 7 and against surface 10 of the plate 4. This high
pressure urges the plate 4 in the forward position and thus arm 3
maintains the bolt 1 in a locked forward position until the projectile has
left the muzzle allowing the gas pressure to drop. When the gas pressure
in the barrel and locking chamber has decreased sufficiently, the rearward
momentum of the cartridge case against the forward bolt surface causes the
bolt to be driven rearwardly. As the bolt nears the rearward position as
shown in FIG. 2, plate 4 passes over and closes gas port 8 trapping and
compressing the remaining gas in the rear portion 24 of the gas locking
chamber to cushion the movement of the bolt 1 as it reaches the end of its
remaining rearward travel. Thus, the gas present in locking chamber
portion 24 acts as a buffer or air valve in retarding the blowback action
and preventing the bolt from slamming to its fully recoiled position. Vent
17 which had been blocked closed with the bolt in its forward position
(FIG. 1) by cross pin 13 is now exposed and allows this remaining gas to
vent slowly into chamber portion 26 (FIG. 2) as the bolt comes to rest at
the end of its cycle. Port 18 in arm 3 now communicates with the chamber
position thereby venting any remaining gases into the atmosphere. This
provides for fully venting the hot gases from the locking chamber which
also improves the cooling of the weapon during the firing cycle.
It will be appreciated that the use of the gas locking chambers, as
described hereinabove, will yield weapons which are relatively easy to
manufacture, have few assembly parts, and are simple to break down and
repair, and at the same time utilize high-powered cartridges without the
necessity of complicated mechanical breech assemblies or unduly heavy
bolts or barrels. Again, any type of trigger or recoil spring assembly, as
well as other components, may be incorporated in to such weapons, as will
be appreciated by those skilled in the art. Further, the concept herein
may be used in rifles, pistols, shotguns, submachine guns, machine guns
and automatic cannon of various sorts.
* * * * *
|
|
 |
|
 |
Description |
|
