U.S. patent application number 12/384354 was filed with the patent office on 2010-10-07 for versatile buffer/spring assembly for a firearm.
This patent application is currently assigned to Abrams Airborne. Invention is credited to Eric Kincel.
Application Number | 20100251587 12/384354 |
Document ID | / |
Family ID | 42824985 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100251587 |
Kind Code |
A1 |
Kincel; Eric |
October 7, 2010 |
Versatile buffer/spring assembly for a firearm
Abstract
A collapsible stock for a firearm and a firearm therewith. The
firearm uses an action mechanism to discharge a cartridge so that a
bullet travels through a barrel have a length of between seven
inches and twenty four inches. The collapsible stock assists the
action mechanism in ejecting a spent cartridge and injecting a
fresh cartridge into the action. The collapsible stock is a
slidable butt member which engages a stock tube. Within the stock
tube is a uniform spring capable of reliably operating for varying
barrel lengths together with a buffer mechanism working with the
spring.
Inventors: |
Kincel; Eric; (Tucson,
AZ) |
Correspondence
Address: |
Mark E. Ogram
Ste. 110-186, 6990 E. 22nd Street
Tucson
AZ
85710-5192
US
|
Assignee: |
Airborne; Abrams
|
Family ID: |
42824985 |
Appl. No.: |
12/384354 |
Filed: |
April 3, 2009 |
Current U.S.
Class: |
42/1.06 ;
42/71.01; 42/75.03 |
Current CPC
Class: |
F41C 23/06 20130101;
F41C 23/04 20130101; F41A 3/84 20130101 |
Class at
Publication: |
42/1.06 ;
42/71.01; 42/75.03 |
International
Class: |
F41C 23/04 20060101
F41C023/04; F41C 23/06 20060101 F41C023/06; F41C 23/14 20060101
F41C023/14 |
Claims
1. A collapsible stock for a firearm having a barrel having a
length of between seven inches and twenty four inches, said
collapsible stock comprising: a) a slidable butt member; b) a stock
tube having an open end and a closed end, said receiver extension
configured to receive said slidable butt member therearound; c) a
spring positioned within said stock tube; and, d) a buffer
mechanism positioned to engage said spring within said stock tube
proximate to the open end of said stock tube.
2. The collapsible stock according to claim 1, wherein a single
uniform spring is applied irrespective of the barrel length.
3. The collapsible stock according to claim 2, wherein said spring
has a wire diameter of substantially 0.072 inches.
4. The collapsible stock according to claim 3, wherein said spring
has 44 total coils and exerts a spring rate of substantially 1.35
pounds per inch.
5. The collapsible stock according to claim 1, where said buffer
mechanism has a mass between 4.2 and 5.1 ounces.
6. The collapsible stock according to claim 5, wherein said buffer
includes: a) a sleeve member having an open end and a closed end,
except for a collar thereon, said sleeve member having a diameter
less than a diameter of said spring; b) at least four weights
contained within said sleeve member, at least one of said weights
having a mass greater than the mass another weight; and, c) a
bumper secured to and sealing the open end of said sleeve
member.
7. The collapsible stock according to claim 6, wherein an overall
length of said buffer is between 3.8 and 4.1 inches.
8. The collapsible stock according to claim 1, wherein said stock
tube has an internal length of between 7.5 and 8 inches.
9. The collapsible stock according to claim 8, wherein said
internal length of said stock tube is adjustable by an
operator.
10. The collapsible stock according to claim 8, wherein, a) said
stock tube includes a butt stock receiver having at least two
engaging points; and, b) said slidable butt is configured to slide
over an outside of said stock tube and selectively engage one of
said at least six engaging points.
11. A mechanism receiving a slidable butt member for a firearm
having a barrel having a length of between seven inches and twenty
four inches, said collapsible stock comprising: a) a stock tube
having an open end and a closed end, said receiver extension
configured to receive the slidable butt member; b) a uniform spring
being used irrespective of the barrel length; and, c) a buffer
mechanism positioned to contact said spring within said stock tube
proximate to the open end of said stock tube.
12. The mechanism according to claim 11, wherein said spring has a
wire diameter of substantially 0.072 inches and has 44 total coils
and exerts a spring rate of substantially 1.35 pounds per inch.
13. The mechanism according to claim 12, wherein said buffer
includes: a) a sleeve member having an open end and a closed end,
said sleeve member, except for a collar thereon, has a diameter
less than a diameter of said spring; b) at least four weights
contained within said sleeve member, at least one of said weights
having a mass greater than the mass another weight; and, c) a
bumper secured to and sealing the open end of said sleeve member;
and, d) wherein a mass of said buffer is a mass between 4.2 and 5.1
ounces.
14. The mechanism according to claim 13, wherein an overall length
of said buffer is between 3.8 and 4.1 inches.
15. The mechanism according to claim 11, wherein said stock tube
has an internal length of 7.771 inches.
16. A firearm comprising: a) an action mechanism configured to
engage a cartridge and selectively fire said cartridge; b) a barrel
having a length of between seven inches and twenty four inches,
said barrel receiving a bullet from said cartridge; and, c)
collapsible stock assembly positioned to assist said action
mechanism in ejecting a spent cartridge and injecting a fresh
cartridge into said action in preparation for firing, said
collapsible stock assembly having, 1) a slidable butt member, 2) a
stock tube having an open end and a closed end, said receiver
extension configured to receive said slidable butt member
therearound; 3) a uniform spring positioned within said stock tube,
said uniform spring being used irrespective of the barrel length,
and, 4) a buffer mechanism positioned to engage said spring within
said stock tube proximate to the open end of said stock tube.
17. The firearm according to claim 16, wherein said spring has a
wire diameter of substantially 0.072 inches, 44 total coils and
exerts a spring rate of substantially 1.35 pounds per inch.
18. The firearm according to claim 16, wherein said buffer
mechanism has a mass between 4.2 and 5.1 ounces and an overall
length of said buffer is between 3.8 and 4.1 inches, said buffer
mechanism having: a) a sleeve member having an open end and a
closed end, said sleeve member, except for a collar thereon, having
a diameter less than a diameter of said spring; b) at least four
weights contained within said sleeve member, at least one of said
weights having a mass greater than the mass another weight; and, c)
a bumper secured to and sealing the open end of said sleeve
member.
19. The firearm according to claim 16, wherein said stock tube has
an internal length of between 7.5 and 8 inches.
20. The firearm according to claim 16, wherein, a) said stock tube
includes a butt plate receiver having at least six engaging points;
and, b) said slidable butt is configured to slide over an outside
of said stock tube and selectively engage one of said at least six
engaging points.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to firearms and more
particularly to the stock tube/spring/buffer combination used in
automatic and semi-automatic rifles and carbines and the
M16/AR15.
[0002] The M16/AR15 series of rifles was originally designed to use
a twenty inch barrel; with the gas port located approximately
thirteen inches from the breach. The original design also used an
operating spring and buffer system designed specifically for the
fixed stock.
[0003] As the battlefield changed, so too did the methods and
tactics used by our military forces. These changes demanded that
the individual weapon become shorter, more compact and easier to
handle in confined spaces. This was ultimately accomplished by
shortening the weapon's barrel and developing a telescoping stock
system, which allowed the user to select varying degrees of "length
of pull". This telescoping stock system also used a new shorter
action spring and was/is unable to use the existing action spring
from the rifle version.
[0004] The new, shorter weapon is called a "carbine". One of the
shortcomings of the carbine is that when the barrel is shortened,
the location of the gas port was also moved closer to the breach.
The high pressure gases that are bled off at this port are what
provide the energy for the weapon to operate; however, the gas
pressures of the new shorter carbine system are nearly double what
the original system was designed to do. This causes significantly
higher operating pressures and forces the weapon to operate at much
higher cyclic rates and with a noticeably increased bolt
velocity.
[0005] To counter this, the carbine action spring is stiffer than
the rifle action spring, and the functional length of the carbine
spring is much shorter than the rifle spring. Attempts to run the
longer rifle length barrel on a weapon with the shorter carbine
length recoil system (collapsible stock tube, spring, and buffer)
have proven to be an unreliable design.
[0006] This means that the two weapons, the rifle and carbine,
require different combinations of stock tube, spring, and buffer in
order to operate properly; otherwise, the weapons are not reliable;
thereby forcing an expanded inventory of replacement and
manufacturing parts.
[0007] It is clear there is a need for an improved stock
tube/buffer/spring assembly to improve reliability and also
decrease the complexity of the firearm systems.
SUMMARY OF THE INVENTION
[0008] The invention relates to a collapsible stock for a firearm
and the improved firearm using such stock. While there are many
firearms, this invention is particularly useful for a firearm which
has models ranging from a carbine to a rifle (barrel length between
seven inches and twenty four inches).
[0009] Such firearms are described in U.S. Pat. No. 6,637,142,
entitled "Firearm Assembly" issued to Reynolds on Oct. 28, 2003;
U.S. Pat. No. 6,487,805, entitled "Firearm Assembly" issued to
Reynolds on Dec. 3, 2002; and U.S. Pat. No. 7,448,307, entitled,
Gas Operated Semi-Automatic Rifle" issued to Dafinov, on Nov. 11,
2008; all of which are incorporated hereinto by reference.
[0010] The firearm uses an action mechanism to discharge a
cartridge so that a bullet travels through the barrel. Those of
ordinary skill in the art readily recognize a variety of action
mechanisms, such as, but not limited to, U.S. Pat. No. 4,433,610,
entitled "Open Bolt Firing Mechanism for Automatic Firearm" issued
to Tatro on Feb. 28, 1984; U.S. Pat. No. 6,722,255, entitled
"Apparatus and Method for Actuating a Bolt Carrier Group as a
Receiver Assembly" issued to Herring on Apr. 20, 2004; U.S. Pat.
No. 7,461,581m, entitled "Self-Cleaning Gas Operating System for a
Firearm" issued to Leitner-Wise on Dec. 9, 2008; U.S. Pat. No.
7,418,898, entitled "M16 Modified With Push Rod Operating System
and Conversion Thereof' issued to Desomma on Sep. 2, 2008; and,
U.S. Pat. No. 6,851,346, entitled "Firearm Bolt Catch Assembly"
issued to Herring on Feb. 8, 2005; all of which are incorporated
hereinto by reference.
[0011] A collapsible stock permits the firearm to be used in a
variety of situations (e.g. to facilitate close quarters operations
such as within a building), by users of varying arm length and
height, and to accommodate other equipment (e.g. thick body
armor).
[0012] Collapsible stocks are well known in the art. Examples of
such are described in U.S. Pat. No. 6,925,744, entitled "Modular
Firearm Buttstock" issued to Kincel on Aug. 9, 2005; and, U.S. Pat.
No. 7,363,740, entitled "Modular Firearm Buttstock" issued to
Kincel on Apr. 29, 2008; both of which are incorporated hereinto by
reference.
[0013] Further, in the case of the M16/AR14 rifle and carbine, the
collapsible stock assembly assists the action mechanism in ejecting
a spent cartridge and injecting a fresh cartridge into the action.
In this context, the collapsible stock slides upon a stock tube.
Within the stock tube is a spring working with a buffer mass which
assists the action mechanism in ejecting the spent cartridge.
[0014] Such collapsible stock assemblies for the M16 and AR14
rifles are described in U.S. Pat. No. 4,057,003, entitled "Open
Bolt Conversion Apparatus" issued to Atchisson on Nov. 8, 1977;
and, U.S. Pat. No. 6,971,202, entitled "Gas Operated Action for
Auto-Loading Firearms" issued to Bender on Dec. 6, 2005; both of
which are incorporated hereinto by reference.
[0015] In the present invention, the stock tube ideally has a
working length of 7.771 inches although a working length of between
7.5 and 8 inches is also operable as indicated below. This is the
length from the open end to the base of the stock tube.
[0016] In some embodiments of the invention, a plate with screw
adjustment is provided in the stock tube, permitting the working
length to be adjusted by user to obtain specific operating
characteristics.
[0017] The present invention provides a system which uses a stock
tube with a single uniform spring and associated buffer regardless
of the length of the barrel of the firearm; hence, a single spring
is used for reliable operation of a firearm whether that firearm is
a carbine (typically requiring a shorter, more durable spring), or
a rifle, (requiring a less durable spring for reliable
operation).
[0018] The preferred spring used for either the carbine (barrel
length as short as seven inches) or the rifle (barrel length up to
twenty-four inches) is that described in MIL-W-13855, incorporated
hereinto by reference.
[0019] The buffer used in this invention is made from a sleeve
member having an open end and a closed end and has a diameter
(except for an engaging collar) less than a diameter of said
spring, thereby allowing the buffer to fit within the spring
(except for the collar at one end of the buffer). In the preferred
embodiment, four weights are contained within the sleeve member and
are chosen so that the total mass of the assembled buffer is
between 4.2 and 5.1 ounces. A bumper (ideally made from plastic) is
secured to the open end of the sleeve member to seal the open end
of said sleeve member and contain the weights therein.
[0020] The invention, together with various embodiments thereof,
will be more fully explained by the accompanying drawings and the
following descriptions thereof.
DRAWINGS IN BRIEF
[0021] FIG. 1 is an illustration of the parts used in the present
invention.
[0022] FIG. 2 illustrates the spring and buffer placed within the
hollow receiver.
[0023] FIG. 3 illustrates the components of the inventions
preferred buffer.
[0024] FIG. 4 is a perspective view of the assembled firearm.
[0025] FIG. 5 is a view of an embodiment of the hollow receiver
which has an adjustable effective length.
DRAWINGS IN DETAIL
[0026] FIG. 1 is an illustration of the parts used in the present
invention. Upper receiver 12 is configured to engage mechanism 17
and contain the bolt carrier 13 therebetween. Mechanism 17 includes
a stock tuber 16 which is configured to accept butt member 10
(sliding on stock tube 16) and selectively engaging with lower
receiver 15.
[0027] Stock tube 16 is configured to accept spring 11 therein as
well as buffer 14. Spring 11 complies with MIL-W-13855. With a wire
diameter of 0.072 inches, 44 coils, a spring rate 1.35 and a free
length of 12.5 inches, spring 11 reliably operates a firearm having
a barrel length ranging from a carbine length (7 inches) to a rifle
length (24 inches).
[0028] Buffer 14 has an overall length of between 3.8 and 4.1
inches and a mass of between 4.2 and 5.1 ounces. This length/mass
combination of buffer 14 assures that the operation of the firearm,
regardless of the barrel length, is reliable and steady.
[0029] To accommodate spring 11 and buffer 14, stock tube 16 has an
internal operating length of between 7.5 and 8 inches; ideally the
internal operating length is 7.771 inches. This length allows lower
receiver 15 to fully accept the spring 11//buffer 14 combination
and has seven engaging points so that butt member 10 is given seven
degrees of freedom for optimal operator satisfaction.
[0030] FIG. 2 illustrates the spring and buffer placed within the
hollow receiver. Hollow receiver 16 now contains spring 11 and
buffer 14. As noted earlier, the internal length of hollow receiver
16 (operating length) is 7.771 inches, allowing spring 11 and
buffer 14 to be properly contained therein. Placement of spring 11
and buffer 14 within hollow receiver 16 is via opening 20.
[0031] FIG. 3 illustrates the components of the invention's
preferred buffer. Buffer 14 includes collar 35 which is designed to
rest on the end of the spring (not shown) as illustrated in FIG.
2.
[0032] Buffer 14 is hollow and contains weights 32 and 33 therein
which are spearated by discs 34. Tungsten weight 32 is denser and
hence heavier than steel weights 33. By selective application of
the number of tungsten weights 32 and steel weights 33, the overall
mass of buffer 14 is established in the range of 3.8 ounces to 4.1
ounces.
[0033] Plastic plug 31 is used to contain weights 32 and 33 within
buffer 14. Plastic plug 31 is held in place with pin 30.
[0034] FIG. 4 is a perspective view of the assembled firearm. Once
assembled, the firearm of FIG. 4 has a butt member 10, an action 41
(including upper receiver 12), and barrel 40. Internal to mechanism
17 is the stock tube/spring/buffer as discussed before. While the
stock tube/spring/buffer within mechanism 17 is constant, the
barrel length is chosen to meet the specific requirements of the
time or application. The length of barrel 40 is now able to range
from seven inches to twenty-four inches without having to modify
the stock tube/spring/buffer.
[0035] FIG. 5 is a view of an embodiment of the stock tube which
has an adjustable effective length. In this embodiment of the stock
tube, stock tube 50 has opening 51 which permits the insertion of
the spring/buffer as discussed above. This embodiment of hollow
receiver 50 allows the adjustment of the effective length D, 52, by
way of base plate 56 which is moved within the stock tube 50 by
screw mechanism 53. Motion of screw 53, as indicated by arrow 54A,
causes base plate 56 to move, as indicated by arrow 54B. This
allows adjustment of the overall length D, 52, so as to adjust the
tension/response of the spring/buffer (not shown).
[0036] Weep holes 55 permit water which might be collected within
hollow receiver 50 during use in the field to be exhausted.
[0037] It is clear from the foregoing that the present invention
creates a highly reliable and versatile assembly for a firearm such
as the M16/AR14.
* * * * *