U.S. patent number 3,893,369 [Application Number 05/334,976] was granted by the patent office on 1975-07-08 for inertia device for retarding the unlocking of a bolt assembly.
This patent grant is currently assigned to Benelli S.p.A. Divisione Armi. Invention is credited to Giovanni Benelli.
United States Patent |
3,893,369 |
Benelli |
July 8, 1975 |
Inertia device for retarding the unlocking of a bolt assembly
Abstract
The pistol comprises a bolt provided with ribs extending
transversely to the bolt axis and adapted to engage in and
disengage from corresponding mating grooves provided in the
receiver breech upon a slight rotation of said bolt with respect to
said receiver breech. A locking link provided between the bolt and
the bolt carrier is caused, upon firing, to rotate in such a
direction that said link holds said bolt urged against the receiver
breech, with said ribs engaged in the mating grooves. Once the
inertial force of said bolt carrier has failed, the residual
pressure of exhaust gases applies a force to said bolt which causes
the bolt to rotate with respect to said receiver breech so as to
disengage said ribs from the associated grooves in said receiver
breech.
Inventors: |
Benelli; Giovanni (Urbino,
IT) |
Assignee: |
Benelli S.p.A. Divisione Armi
(Urbino, IT)
|
Family
ID: |
25711124 |
Appl.
No.: |
05/334,976 |
Filed: |
February 23, 1973 |
Foreign Application Priority Data
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|
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Feb 29, 1972 [IT] |
|
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44012/72 |
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Current U.S.
Class: |
89/182; 89/184;
89/196 |
Current CPC
Class: |
F41A
3/32 (20130101) |
Current International
Class: |
F41A
3/32 (20060101); F41A 3/00 (20060101); F41d
001/08 () |
Field of
Search: |
;89/180,181,182,183,184,190,194,195,196,197 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Amster & Rothstein
Claims
What I claim is:
1. An automatic firing and defense pistol comprising
a fixed barrel having an axis;
a bolt carrier axially aligned with said barrel and located
adjacent thereto;
said bolt carrier including a stop element extending transversely
to said axis;
a bolt assembly slidably mounted within said bolt carrier, said
bolt assembly having a plurality of projecting ribs, and said ribs
having faces inclined with respect to said axis;
a receiver breech attached to said barrel and including a plurality
of grooves corresponding to and providing mating engagement with
said ribs prior to firing of the pistol;
a link having one end pivotally mounted on an end of said bolt
assembly remote from said barrel and the other end of said link
freely bearing against said stop element;
a preloaded spring associated with said barrel and applying a bias
to said stop element thereby exerting a thrust force on said link
to maintain engagement of said ribs;
said link having an inclination of approximately 45.degree. to said
axis prior to firing, and said link temporarily maintaining said
inclination and rib engagement upon firing due to inertia force of
said bolt carrier and stop element; and
said link movable to be axially aligned with said barrel due to
force of residual gases following firing thereby allowing
disengagement of said ribs and sliding movement of said bolt
assembly.
2. An automatic firing and defense pistol according to claim 1
wherein said ribs are two in number and have a transverse crescent
configuration.
Description
This invention relates to automatic firing and defense pistols.
Automatic firing and defense pistols heretofore known of the kind
having a fixed barrel and a recoiling bolt carrier are limited in
use to very low pressure ammunition. This kind of weapons is
provided with a striking bolt assembly. In operation the barrel is
stationary, whereas the bolt carrier recoils due to the pressures
developed by the gases on the cartridge cases.
This system generally accepted in almost all of the automatic
firing and defense pistols, has the advantage of being simple in
construction and accurate in firing; however, this system is
suitable only where the pressures are not very high, otherwise it
is necessary to reinforce the locking of the bolt assembly by means
of strong recoil springs or increase the bolt carrier inertia, in
which case the bolt carrier would become very heavy, which results
in the pistol being difficult to operate and of considerable
weight. The above drawbacks practically show the reasons why the
fixed barrel and recoiling bolt carrier system is generally
employed with short-barrel weapons and low muzzle velocity of
bullets.
It is the object of this invention to overcome these drawbacks.
The automatic firing and defense pistol according to the present
invention is characterized in that it comprises a bolt provided
with ribs extending transversely to the bolt axis and adapted to
engage in and disengage from corresponding mating grooves provided
in the receiver breech upon a slight rotation of said bolt relative
to said receiver breech, and a link one end of which is articulated
in a cavity provided in said bolt and the other end of which in
subjected to the pressure exerted thereon by said bolt carrier
under the bias of a preloaded spring, the contact of said link with
said bolt and bolt carrier being established in such locations
relative to the pistol axis that, upon firing, the force applied to
said link by said bolt carrier due to the inertia of the latter and
the force applied to said link by said bolt due to the exhausted
gases will generate a torque which causes said link to rotate in
such a direction that said link holds said bolt urged against the
receiver breech, with said ribs engaged in the mating grooves which
are provided in the receiver breech whereas, once the inertial
force of said bolt carrier has failed, the residual pressure of
exhaust gases applies a force to said bolt which causes the bolt to
rotate relative to said receiver breech so as to disengage said
ribs from the associated grooves provided in said receiver
breech.
By means of the above arrangement a retarded unlocking of the bolt
after firing is obtained without the necessity of using strong
recoil springs or a very heavy bolt carrier for increasing the
inertia thereof.
This invention will readily become apparent upon reading the
following specification of one embodiment of the invention given by
way of example only and therefore not limitative, taken in
connection with the accompanying drawing, wherein:
FIG. 1 is a diagrammatic, fragmentary, axial sectional view of a
pistol in accordance with the invention, with the bolt assembly in
a locking position and therefore ready for firing;
FIG. 2 is a sectional view similar to FIG. 1, showing the pistol
after firing;
FIG. 3 is a sectional view similar to FIG. 1 and 2, showing the
pistol with the bolt assembly in an unlocking position;
FIG. 4 is a fragmentary, axial sectional view of the receiver
breech of the pistol shown in FIGS. 1 to 3;
FIG. 5 is a fragmentary cross-section of the receiver breech taken
along the line 5--5 of FIG. 4;
FIG. 6 is a side elevational view of the bolt assembly of the
pistol of FIGS. 1 to 3; and
FIG. 7 is a cross-section of the bolt assembly taken along the line
7--7 of FIG. 6.
As can be seen from FIGS. 1 to 3, the automatic pistol comprises a
fixed barrel 1, rigidly connected to a receiver breech 10 and a
receiver 9 so as to form an unitary body therewith. A bolt assembly
3 has an outer semicylindrical portion at its bottom provided with
two crescent ribs 7 (see FIGS. 6 and 7) exactly aligned with two
mating grooves 8 provided in the receiver breech 10 (see FIGS. 4
and 5). These crescent ribs 7 have inclined surfaces 12 adapted to
cooperate with corresponding inclined surfaces 11 provided in the
grooves 8.
A bolt carrier 2 fastened to a stop element 5 by means of a splined
coupling (not shown) carries at one end a cylindrical spring
housing 15 for receiving a preloaded spring 6 which bears at one
end against the bottom of the spring housing and at the other end
against a washer 16 received on a spring guide rod 17 extending
from an abutment surface 18 of the receiver breech 10, the spring 6
holding the washer 16 against said abutment surface 18.
The bolt assembly 3 has a spherical cavity provided therein, which
houses a spherical end of a locking link 4, the other end of which
bears against the upper wall of the bolt carrier 2 and also against
the stop element 5 by being held in engagement with the latter by
the force of the spring 6. Assuming that the weapon is charged and
ready for firing, then, under these conditions, the link 4 is
inclined about 45.degree. relative to the bolt axis and the link
exerts on the bolt a thrust which causes the latter to be held-down
with the crescent ribs 7 in firm engagement in the mating grooves 8
of the receiver breech 10 and, at the same time, against the bottom
of the cartridge case 20 of the cartridge introduced into the
barrel 1. The bolt 3 has a through hole 21 provided therein (see
FIG. 7), in which a firing pin 13 is received which is intended to
cooperate with a hammer 14, only fragmentarily shown.
The pistol so described operates as follows:
At the time that the firing pin 13 (FIG. 2) is struck by the hammer
14, the firing pin reaches the cartridge detonator causing the
explosion of the charge and the bolt carrier 2 tends by its own
inertia to maintain its position relative to the other parts of the
weapon which recoil against the hand of the shooter.
To the maintenance of this position also the preloaded spring 6
contributes.
If the receiver and barrel assembly 1-9-10 is taken as reference,
then the inertia of the bolt carrier and stop element assembly 2-5
results in a force acting on the link 4 in a location where it is
in contact with the bolt carrier and stop element assembly 2-5.
Simultaneously, the action of gases on the bolt results in a force
acting on the fulcrum of the link 4.
These two forces form a torque which, with the link 4 being
supposed free, would cause the link to rotate in counterclockwise
direction about its gravity center. Due to the constraints of the
mechanical system according to this invention the resultant, will
be a force tending to hold-down the bolt 3 with the crescent ribs 7
in engagement within the mating grooves 8 of the receiver breech
10.
Therefore, at the most dangerous time that the forces developed by
the propelling gases of the cartridge case violently eject the
bullet, the system provides for an extremely stiff locking of the
bolt assembly.
This condition continues as long as the inertial force of the bolt
carrier-stop element assembly 2-5 is present. Once this force has
failed, the only force acting on the system is that due to the
residual gas pressure acting in the direction of the longitudinal
axis of the barrel.
As the bolt is recoiled by the high pressure developed by the
residual gases, it is no longer held-down by the link 4, which now
is no longer subjected to the force generated by the bolt carrier
inertia and the bolt, therefore, due to the mutual action of
inclined surfaces 12 of the ribs 7 provided on the bolt, and the
mating inclined surfaces 11 of the grooves 8 provided in the
receiver breech 10, it slightly pivots upwards, with the crescent
ribs 7 disengaging from the mating grooves 8 of the receiver breech
10, and therefore, it recoils together with the bolt carrier and
stop element assembly, thereby causing the cartridge case 20 to be
ejected from the pistol. The recoil spring 6 then returns the bolt
forward together with the bolt carrier, thereby introducing a new
cartridge in the barrel; in such a manner the weapon will be again
with the bolt in locked position and ready for firing.
From the above description it will be readily apparent that the
bolt cannot unlock until the recoil movement tends to terminate.
Therefore, the system attains the object to provide a positive bolt
locking for the fraction of time necessary for the bullet to be
ejected from the barrel.
* * * * *