U.S. patent number 3,848,510 [Application Number 05/391,701] was granted by the patent office on 1974-11-19 for bolt locking mechanism for reciprocating gun.
This patent grant is currently assigned to The United States of America as represented by the Secretary of the Navy. Invention is credited to John F. Wolpert.
United States Patent |
3,848,510 |
Wolpert |
November 19, 1974 |
BOLT LOCKING MECHANISM FOR RECIPROCATING GUN
Abstract
A bolt locking mechanism for an automatic weapon having a bolt
housing and n accelerator slidably mounted therein. A firing pin is
attached to the accelerator and the bolt housing has a pair of
linear grooves extending outwardly to the sides of the bolt. A
roller lock is provided in each linear groove and these roller
locks are engageable with cams which lock the accelerator with the
bolt during a portion of the bolt travel. A barrel extension has a
pair of locking grooves which are engageable by the roller locks to
lock the bolt housing with the barrel extension during firing of
the automatic weapon.
Inventors: |
Wolpert; John F. (Louisville,
KY) |
Assignee: |
The United States of America as
represented by the Secretary of the Navy (Washington,
DC)
|
Family
ID: |
23547597 |
Appl.
No.: |
05/391,701 |
Filed: |
August 27, 1973 |
Current U.S.
Class: |
89/173;
89/187.02 |
Current CPC
Class: |
F41A
3/46 (20130101) |
Current International
Class: |
F41A
3/00 (20060101); F41A 3/46 (20060101); F41d
005/02 () |
Field of
Search: |
;89/153,173,174,180,182,183,187CB,188 |
Foreign Patent Documents
|
|
|
|
|
|
|
945,216 |
|
Jul 1956 |
|
DT |
|
945,819 |
|
Jul 1956 |
|
DT |
|
955,392 |
|
Jan 1957 |
|
DT |
|
153,875 |
|
Jul 1938 |
|
OE |
|
Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Sciascia; R. S. Collignon; Paul
S.
Claims
I claim:
1. In an automatic firearm, a bolt locking mechanism
comprising,
a breech housing,
a barrel extension connected to said breech housing having means
for attaching a barrel on one end thereof and having locking
grooves therein,
a bolt slidably mounted in said breech housing, said bolt having
opposed linear slots with parallel surfaces in each side
thereof,
an accelerator slidably mounted in said bolt, said accelerator
having a firing pin attached thereto,
first and second roller lock assemblies each said roller lock
assembly having a shaft with at lesst one pair of flat parallel
surfaces on each end thereof and a roller positioned midway between
said shafts ends with said flat parallel surfaces extending
outwardly from each side of said roller, said parallel surfaces on
each end of said shaft being slidably engageable with the parallel
surfaces of said linear slots in said bolt and each said roller
being engageable with said accelerator, said roller lock assemblies
releasably locking said accelerator with said bolt, and
cam means attached to said breech housing engageable with said
roller lock assemblies for locking said accelerator with said bolt
until a round carried by said bolt reaches a battery position and
said roller lock assemblies unlock said accelerator from said bolt
and lock said bolt to said barrel extension and upon recoil of said
bolt said cam means actuates said roller lock assemblies to unlock
said bolt from said barrel extension and to lock said accelerator
with said bolt.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a breech locking mechanism for
automatic weapons. In automatic weapons, such as machine guns, a
breech head or block is provided in a housing and is locked thereto
during the igniting of a cartridge. After firing, the breech block
is automatically unlocked from the housing and then reciprocated by
either recoil or by gas pressure in order to extract a spent
cartridge and the load a live cartridge into the gun chamber. As
modern day weapons may fire five or six hundred rounds per minute,
the design of breech block locking mechanisms is highly critical as
wear and fatique on the contacting elements will cause the weapon
to jam and malfunction.
Various devices have been used to lock a breech to a housing during
firing. For example, in U. S. Pat. No. 3,348,453, which issued Oct.
24, 1967, to Ernest Muhlemann, a pair of bolt locks are pivotally
connected to a bolt mechanism and these locks are engageable with
slots in the breech housing. The bolt mechanism is unlocked by a
control member which moves rearwardly and permits the bolt locks to
retract.
SUMMARY OF THE INVENTION
The present invention relates to an improved breech locking device
for an automatic weapon. A bolt housing has an accelerator slidably
mounted therein and a firing pin is attached to the forward end of
the accelerator. A pair of roller locks are mounted in linear
grooves in the bolt housing and cams are provided to hold the
roller locks in engagement with the accelerator to prevent forward
movement. The cams permit the roller locks to move outwardly as the
bolt moves forward and unlocks the accelerator from the bolt
housing. The roller locks are engageable with grooves in a barrel
extension and can lock the bolt housing to the barrel extension
during firing. The roller lock is of a two-piece construction
having a cylindrical ring which is mounted or supported on a shaft
having flats thereon which engage in the linear groove.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a machine gun using the bolt
mechanism of the present invention;
FIG. 2 is a partial sectional view showing a bolt mechanism prior
to entering a barrel extension;
FIG. 3 is a partial sectional view showing a cartridge chambered
and a bolt mechanism unlocked;
FIG. 4 is a partial sectional view showing a bolt mechanism
partially locked to a barrel extension;
FIG. 5 is a partial sectional view showing a bolt mechanism locked
to a barrel extension and a cartridge being fired;
FIG. 6 is a partial sectional view showing a bolt mechanism
unlocked and in a retracting condition; and
FIG. 7 is a side view of a bolt mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 of the drawing, there is shown a machine
gun 11 having a recoil barrel 12 attached to gun housing 13. By way
of example, gun 11 might be an air-cooled weapon that fires from
350 to 600 rounds of ammunition per minute, with the ammunition
being fed into the gun by a mechanical feeder while the rounds are
presented in a continuous link belt.
Referring now to FIGS. 2 through 7 of the drawings, barrel 12 is
attached, as by threading, to barrel extension 14 which is part of
housing 13. Barrel extension 14 is provided with a bore 15 for
receiving a cartridge 16 and is also provided with a chamber 17 for
receiving a bolt 18 which chambers cartridge 17 prior to firing and
extracts the spent cartridge after firing. An accelerator 19 is
slidably mounted in bolt 18 and carries a firing pin 21. Bolt 18 is
provided with a pair of linear grooves 22 and 23 which are opposed
one another and extend to the sides of bolt 18. Roller lock
assemblies 24 and 25 are positioned in grooves 22 and 23,
respectively, and are used to retain accelerator 19 until cartridge
16 is fully chambered. A pair of cams 26 and 27 are provided on the
sides of housing 13 and are used to facilitate locking and
unlocking of roller lock assemblies 24 and 25.
As best shown in FIG. 7 of the drawaings, each roller lock assembly
is comprised of a shaft 28, which has flat sides engageable with
the sides in the groove in which it operates, and a roller 29 is
provided on shaft 28 and is engageable with one of the cams. Barrel
extension 14 is provided with a pair of cam grooves 31 and 32, and
these grooves are engageable by the roller lock assemblies 24 and
25, respectively.
OPERATION
Firing action of the weapon shown in FIG. 1 of the drawings begin
when bolt 18 is released from a sear in a manner well-known in the
art. A round 16 on the lower face of the bolt is chambered, while a
round in the feeder is being picked up on the upper face of the
bolt. A more complete description of this loading operation can be
found in U. S. Pat. No. 3,563,132, which issued FEB. 16, 1971, to
Cashen et al.
Bolt 18 is driven forward by a drive spring (not shown) and, as
bolt 18 moves into battery position, roller lock assemblies 24 and
25 move outwardly into grooves 31 and 32, as best shown in FIG. 4
of the drawings. As shown in FIG. 5 of the drawings, as the roller
lock assemblies move completely into grooves 31 and 32, accelerator
19 is free to move forward, and inertia bar 33 drives accelerator
19 forward thereby forcing firing pin 21 into the primer of round
16. As round 16 fires, the recoil components of weapon 11 begin
their rearward movement, with bolt 18 still being locked to barrel
extension 14. When roller lock assemblies 24 and 25 engage cams 26
and 27, these roller lock assemblies are cammed inwardly and bolt
18 is unlocked from barrel extension 14. Roller lock assemblies 24
and 25 then move accelerator 19 rearwardly with respect to bolt 19
and then again lock accelerator 19 with bolt 18.
By way of example, with weapon 11 being chambered to fire 20mm
ammuition, when bolt 18 begins its rearward movement, bolt 18 pulls
barrel extension assembly about 13/8 inches before roller lock
assemblies are cammed inwardly to free the bolt 18 from barrel
extension 14. A barrel recoil spring then forces barrel extension
14 back into a firing position.
It can be seen that roller lock assemblies 24 and 25 are retained
in linear grooves 22 and 23, respectively, and that shaft 28 has
flats so that there is area contact between shaft 28 and the groove
in which it operates. These features greatly reduce the stress
levels on rollers 29 and thus prevent wear and malfunction.
It can thus be seen that the present invention provides an improved
bolt locking mechanism for an automatic weapon. Obviously many
modifications and variations of the present invention are possible
in the light of the above teachings. It is therefore to be
understood, that within the scope of the appended claims, the
invention may be practiced otherwise than as specifically
described.
* * * * *