U.S. patent application number 13/539859 was filed with the patent office on 2013-03-21 for firearm having an indirect gas impingement system.
The applicant listed for this patent is Michael J. Brown. Invention is credited to Michael J. Brown.
Application Number | 20130068089 13/539859 |
Document ID | / |
Family ID | 41463338 |
Filed Date | 2013-03-21 |
United States Patent
Application |
20130068089 |
Kind Code |
A1 |
Brown; Michael J. |
March 21, 2013 |
FIREARM HAVING AN INDIRECT GAS IMPINGEMENT SYSTEM
Abstract
A firearm including a barrel having a breech and a muzzle
defining a length of the barrel is disclosed. The firearm includes
a hand guard having a first end and a second end with a front sight
is attached to at least one of the barrel adjacent the muzzle and
the second end of the hand guard. A housing is coupled to the front
sight and defines a chamber having a piston disposed therein and
movable between static and displaced positions. A receiver is
coupled to the first end and a bolt carrier is disposed within the
receiver and moveable between firing and rearward positions. A
carrier key is attached to the bolt carrier and moves concurrently
with the bolt carrier and a rod is permanently affixed to the
carrier key and extends to a distal end with the piston engaging
the distal end when moving to the displaced position.
Inventors: |
Brown; Michael J.;
(Baltimore, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Brown; Michael J. |
Baltimore |
MD |
US |
|
|
Family ID: |
41463338 |
Appl. No.: |
13/539859 |
Filed: |
July 2, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12496000 |
Jul 1, 2009 |
8210089 |
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13539859 |
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61133624 |
Jul 1, 2008 |
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61211288 |
Mar 27, 2009 |
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Current U.S.
Class: |
89/193 ;
42/71.01; 89/191.01 |
Current CPC
Class: |
F41A 5/26 20130101; F41C
23/16 20130101; F41A 5/18 20130101; F41G 1/02 20130101; F41A 5/24
20130101 |
Class at
Publication: |
89/193 ;
42/71.01; 89/191.01 |
International
Class: |
F41A 5/18 20060101
F41A005/18; F41G 1/02 20060101 F41G001/02; F41A 5/26 20060101
F41A005/26; F41C 23/16 20060101 F41C023/16 |
Claims
1-40. (canceled)
41. A firearm comprising: a barrel defining a first bore extending
along a longitudinal axis and having a breech and a muzzle defining
a length of said barrel; a hand guard defining a second bore
extending substantially parallel to said longitudinal axis and
having a first end coupled to said breech and a second end spaced
from said first end along said longitudinal axis toward said
muzzle; a front sight supported by one of said barrel and said hand
guard; a housing coupled to said front sight; and a support at
least partially disposed between said front sight and said hand
guard with said support being at least partially complementary in
configuration with a portion of said housing for supporting said
housing and said front sight relative to said hand guard when said
hand guard is disposed over said barrel and for allowing removal of
said housing when at least a portion of said hand guard is removed
from said barrel.
42. A firearm as set forth in claim 41 wherein said support
includes a seat supporting said housing with said seat being
disposed within said hand guard between said first and second
ends.
43. A firearm as set forth in claim 41 wherein said support and
said hand guard are integrally formed of a homogenous metal
material.
44. A firearm as set forth in claim 41 wherein said support is
mounted to said second end of said hand guard with said front sight
and said housing being supported by said support.
45. A firearm as set forth in claim 42 wherein said support
includes a projection extending from said second end of said hand
guard toward said muzzle to support said front sight and said
housing.
46. A firearm as set forth in claim 45 wherein said projection
includes a pair of fingers spaced from each other, and wherein said
front sight includes a body disposed between said fingers.
47. A firearm as set forth in claim 45 wherein said projection
includes an opening and wherein said front sight includes a body
with said body defining an orifice, said orifice aligning with said
opening when said body is mounted to said projection, and further
including a mounting pin disposed within said orifice and said
opening to fixedly mount said front sight to said projection with
said mounting pin being removable for selectively detaching said
front sight from said hand guard.
48. A firearm as set forth in claim 47 wherein said projection
includes a pair of fingers spaced from each other with each of said
fingers including a corresponding opening, and wherein said body is
disposed between said fingers.
49. A firearm as set forth in claim 48 wherein a portion of said
hand guard aligns with said openings in said fingers when in an
assembled position to prevent removal of said pin from said
openings and said orifice.
50. A firearm as set forth in claim 41 wherein said housing defines
a chamber extending along a piston axis with a piston disposed
within said chamber and movable along said piston axis between a
static position and a displaced position, with said front sight,
said housing and said piston removable as a unit for selectively
detaching said unit from one of said barrel and said hand
guard.
51. A firearm as set forth in claim 50 wherein said barrel defines
a first port and said housing defines a second port in fluid
communication with said first port for routing exhaust gases into
said chamber of said housing to move said piston from said static
position to said displaced position.
52. A firearm as set forth in claim 51 a regulator partially
disposed in said housing and abutting said piston when said piston
is in said static position with said regulator defining a plurality
of apertures each having a different diameter with one of said
apertures in fluid communication with said second port for routing
exhaust gases from said barrel to said chamber of said housing.
53. A firearm as set forth in claim 41 wherein said support is
further defined as a cradle having a first segment coupled to said
front sight for supporting said housing.
54. A firearm as set forth in claim 53 wherein said cradle further
includes a second segment formed in said hand guard and spaced
substantially parallel to said first segment for supporting said
housing therebetween.
55. A firearm as set forth in claim 53 wherein said housing
includes a front end, a back end and a central portion disposed
between said front and back ends with said housing defining a
chamber extending along a piston axis between said front and back
ends and further including a piston disposed within said chamber
and movable along said piston axis between a static position and a
displaced position, and wherein said first segment includes a first
base engaging said central portion of said housing with said first
base having a pair of base ends and a first flange extending from
one of said base ends and abutting said front end of said
housing.
56. A firearm as set forth in claim 55 wherein said first base
includes a second flange extending from another one of said base
ends and disposed adjacent said back end of said housing.
57. A firearm as set forth in claim 56 wherein said second segment
includes a second base engaging said central portion of said
housing with said second base having a pair of base ends and a
third flange extending from one of said base ends of said second
base and opposing said first flange with said third flange abutting
one of said front end of said housing and said first flange when
said hand guard is disposed over said barrel.
58. A firearm as set forth in claim 57 wherein said second base
includes a fourth flange extending from another one of said base
ends of said second base and opposing said second flange with said
fourth flange adjacent said back end of said housing when said hand
guard is disposed over said barrel.
59. A firearm as set forth in claim 53 further including a support
block attached to said first segment and abutting said barrel for
supporting said housing relative to said front sight and said
barrel.
60. A firearm as set forth in claim 59 further including a stem
attached to said support block and said front sight with said first
segment and said support block each defining a first opening for
receiving said stem and said stem defining a second opening in
fluid communication with said barrel and said housing for routing
exhaust gases from said barrel into said chamber of said housing to
move said piston from said static position to said displaced
position.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The subject patent application claims priority to and the
benefits of U.S. Provisional Patent Application Ser. No.
61/133,624, filed on Jul. 1, 2008 and U.S. Provisional Patent
Application Ser. No. 61/211,228, filed on Mar. 27, 2009.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The subject invention relates to firearms and more
specifically to firearms having an indirect gas impingement
system.
[0004] 2. Description of the Prior Art
[0005] Firearms typically include a receiver that houses several
working components of the firearm, including firing components,
with a barrel extending from the receiver. There are various
classes of firearms that operate in different manners. One class of
firearm utilizes a bolt carrier is disposed in the receiver that is
moveable between a firing position, from which a live round of
ammunition can be fired, and a retracted position, from which a
spent casing is ejected. The movement of the bolt carrier and
ejection of the casing can be accomplished with a direct gas
impingement or indirect gas impingement system. Examples of gas
impingement type firearms include the M16, the M4.RTM., such as the
M4.RTM. carbine, and the AR-15.RTM., such as the AR-15.RTM.
Platform.
[0006] Firearms having the direct gas impingement system typically
include an ejection port defined by the receiver. Direct gas
impingement systems route exhaust gases back through the firearm to
move the bolt carrier toward the retracted position. In particular,
after firing the firearm, the direct gas impingement system routes
exhaust gases, including any associated debris, from the barrel,
back through a return tube to the bolt carrier, and out the
ejection port of the receiver.
[0007] Firearms having the indirect gas impingement system do not
route the exhaust gases back to the bolt carrier in an effort to
reduce fouling caused by the exhaust gases that may occur with
direct gas impingement type firearms. Instead, the exhaust gases
are used to move a device, such as a piston, that engages the bolt
carrier to move the bolt carrier toward the rearward position. The
device of the prior art utilize multiple components to cause
movement of the bolt carrier. Increasing the components causes an
unwanted increase in the weight of the firearm. Further, increasing
the components also causes serviceability problems with the bolt
carrier and the device.
[0008] Therefore there remains a need to develop a firearm that
utilizes an indirect gas impingement system that is light weight
and simplified to provide easy serviceability and/or retro-fitting
of the components.
SUMMARY OF THE INVENTION AND ADVANTAGES
[0009] The present invention provides for a firearm having a barrel
defining a first bore extending along a longitudinal axis. The
barrel includes a breech and a muzzle defining a length of the
barrel. The firearm includes a hand guard defining a second bore
extending substantially parallel to the longitudinal axis and
having a first end coupled to the breech and a second end spaced
from the first end along the longitudinal axis toward the muzzle. A
front sight is attached to at least one of the barrel adjacent the
muzzle and the second end of the hand guard with a housing coupled
to the front sight and defining a chamber extending along a piston
axis. A piston is disposed within the chamber of the housing and
movable along the piston axis between a static position and a
displaced position. The firearm also includes a receiver coupled to
the first end of the hand guard and the breech of the barrel with
the receiver defining a third bore extending substantially parallel
to the longitudinal axis. A bolt carrier is disposed in the third
bore of the receiver and moveable relative to the receiver along
the longitudinal axis between a firing position and a rearward
position. A carrier key is attached to the bolt carrier and moves
concurrently with the bolt carrier between the firing and rearward
positions with the carrier key extending outwardly above the bolt
carrier and along the piston axis. A rod is permanently affixed to
the carrier key and extends along the piston axis to a distal end.
The piston is adjacent the distal end when in the static position
and the piston engages the distal end when moving to the displaced
position for moving the bolt carrier from the firing position to
the rearward position.
[0010] The present invention also provides for a sight assembly for
the firearm having the barrel and the hand guard disposed about the
barrel. The sight assembly includes the front sight having a body
and an extension coupled to the body with the front sight adapted
to be attached to one of the barrel and the hand guard. The sight
assembly further includes the housing attached to the body and
defining the chamber extending along the piston axis. The sight
assembly also includes the piston disposed within the chamber of
the housing and movable along the piston axis between the static
position and the displaced position with the front sight, the
housing and the piston removable as a unit for selectively
detaching the unit from one of the barrel and the hand guard.
[0011] The present invention further provides for a piston housing
support system for the firearm including the barrel defining the
first bore extending along the longitudinal axis. The piston
housing support system further includes the hand guard defining the
second bore extending substantially parallel to the longitudinal
axis with the hand guard coupled to the barrel. The piston housing
support system also includes the front sight attached to at least
one of the barrel and the hand guard and the housing coupled to the
front sight with a cradle disposed between the front sight and the
hand guard. The cradle is complementary in configuration to a
portion of the housing for supporting the housing relative to the
front sight and the hand guard when the hand guard is disposed over
the barrel and for allowing removal of the housing from the front
sight when the hand guard is removed from the barrel.
[0012] Therefore, the present invention provides for a firearm
having an indirect gas impingement system that allows for easy
serviceability and retro-fitting of the components into existing
firearms while maintaining substantially the same weight of
existing firearm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other advantages of the present invention will be readily
appreciated, as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings.
[0014] FIG. 1 is a perspective view of a firearm in accordance with
the subject invention.
[0015] FIG. 2 is an exploded perspective view of the firearm.
[0016] FIG. 3A is a fragmented partial cross-sectional view of the
firearm with a bolt carrier in an initial position and a bolt in a
first position.
[0017] FIG. 3B is a fragmented partial cross-sectional view of the
firearm with the bolt carrier in a mid position and the bolt in a
second position.
[0018] FIG. 4 is a fragmented partial cross-sectional view of the
firearm with the bolt carrier in a firing position and a piston in
a static position.
[0019] FIG. 5 is an perspective view of a sight assembly exploded
from a hand guard having a first hand guard portion and a second
hand guard portion with a receiver coupled to the first hand guard
portion.
[0020] FIG. 6 is a fragmented partial cross-sectional view of the
firearm with the bolt carrier in a rearward position and the piston
in a displaced position.
[0021] FIG. 7 is an exploded perspective view of the sight
assembly.
[0022] FIG. 8 is a perspective view of the sight assembly.
[0023] FIG. 9 is a perspective view of the piston of the sight
assembly.
[0024] FIG. 10 is an enlarged fragmented cross-sectional view of
the sight assembly mounted to the hand guard.
[0025] FIG. 11 is a perspective interior view of the first hand
guard portion.
[0026] FIG. 12 is an end view of the first and second hand guard
portions coupled to each other.
[0027] FIG. 13 is a perspective view of a second embodiment of the
firearm.
[0028] FIG. 14 is a partial cross-sectional view of the second
embodiment of the firearm.
[0029] FIG. 15 is an enlarged partial cross-section view of the
second embodiment of the firearm.
[0030] FIG. 16 is an interior plan view of a first hand guard
portion of the second embodiment of the firearm.
[0031] FIG. 17 is a perspective interior view of the first hand
guard portion of the second embodiment of the firearm.
[0032] FIG. 18 is an exploded perspective view of a third
embodiment of the firearm.
[0033] FIG. 19 is a fragmented partial cross-sectional view of a
piston housing support system of the third embodiment of the
firearm.
[0034] FIG. 20 is a cross-sectional view of the piston housing
support system of the third embodiment of the firearm.
[0035] FIG. 21 is an exploded side view of a piston assembly of the
third embodiment.
[0036] FIG. 22 is a side view of a first segment of a cradle of the
third embodiment.
[0037] FIG. 23 is a side view of the piston assembly disposed
within the first segment of the third embodiment.
[0038] FIG. 24 is a perspective view of the piston assembly
disposed within the first segment of the third embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Referring to the Figures, wherein like numerals indicate
like or corresponding parts throughout the several views, a firearm
30 is generally shown in FIG. 1. As shown in FIGS. 3A and 3B, the
firearm 30 receives and fires a live round 32 of ammunition
(hereinafter "live round"), also referred to as a cartridge, which
includes a casing 33, a bullet 34, and other components to propel
the bullet 34 as known to those skilled in the art.
[0040] The firearm 30 can be of a certain class of firearms 30 that
utilize a direct gas impingement system or an indirect gas
impingement system to eject a spent casing 33 after firing the
firearm 30. Examples of such types of firearms 30 include the M16,
the M4.RTM., such as the M4.RTM. carbine, and the AR-15.RTM., such
as the AR-15.RTM. Platform. However, it should be appreciated that
the firearm 30 can be of any type without departing from the nature
of the present invention. The firearm 30 described herein is
designed to permit easy retro-fitting of the components to a
variety of currently and/or previously manufactured firearm 30
designs. The firearm 30 as disclosed herein is primarily utilized
in the indirect gas impingement system, as further disclosed
below.
[0041] As shown in FIGS. 1 and 2, the firearm 30 includes a
receiver 36 defining a bore 38 extending substantially parallel to
a longitudinal axis L and houses several working components of the
firearm 30, such as the firing components, i.e. the action. The
bore 38 of the receiver 36 will be referred to as a third bore 38
throughout this description. The receiver 36 defines an ejection
port 40 transverse to the longitudinal axis L with the third bore
38 defining an inner surface 42. As known in the art, the receiver
36 is often divided into an upper receiver portion 44 and a lower
receiver portion 46 attached to the upper receiver portion 44. The
upper receiver portion 44 defines the third bore 38 and the
ejection port 40. A hand grip 48 extends downwardly along the lower
receiver portion 46 for gripping by the user. A buttstock 50
extends rearwardly from the receiver 36 for supporting the firearm
30 against a shoulder of the user.
[0042] A magazine 52, also referred to as a clip, is detachably
mounted to the lower receiver portion 46 and can be loaded with a
plurality of live rounds 32. The firearm 30 further includes a
trigger assembly supported by the receiver 36. The trigger 54
assembly includes a trigger 54 and a hammer (not shown). The
trigger 54 is pulled to move the hammer, which, as discussed
further below, ultimately results in the firing of the firearm
30.
[0043] As also shown in FIGS. 3A, 3B and 4, a barrel 56 is coupled
to the receiver 36 and defines a first bore 58 extending along the
longitudinal axis L. As used herein, the phrase "along the
longitudinal axis" includes components and/or movements aligning
with the longitudinal axis L and/or spaced from and substantially
parallel to the longitudinal axis L. The details of how the barrel
56 is coupled to the receiver 36 is further disclosed and claimed
in U.S. patent application Ser. No. ______ filed concurrently with
the present application (attorney docket no. 065111.00145), which
is incorporated herein by reference. The barrel 56 includes a
breech 60 adjacent the receiver 36 and a muzzle 62 spaced from the
breech 60 along the longitudinal axis L. More specifically, the
firearm 30 includes the barrel 56 defining the first bore 58 and
having the breech 60 and the muzzle 62 defining a length of the
barrel 56. The breech 60 defines a chamber 64 extending along the
longitudinal axis L for receiving one of the live rounds 32. The
chamber 64 will be referred to as a barrel chamber 64 throughout
this description. The live rounds 32 are individually loaded into
the barrel chamber 64 from the magazine 52. The barrel chamber 64
aligns with the first bore 58 such that the bullet 34 moves out of
the barrel chamber 64 and the first bore 58 when firing the firearm
30.
[0044] The barrel 56 also defines a first port 66 between the
breech 60 and the muzzle 62. Alternatively, the first port 66 may
be disposed in the muzzle 62 of the barrel 56. The muzzle 62
includes a distal tip 68 which will be discussed further below. A
gas block 70 is attached to the barrel 56 over the first port 66
with the gas block 70 including a tube 72 coupled to the first port
66 for routing exhaust gases away from the barrel 56 after firing
the bullet 34.
[0045] The firearm 30 includes a hand guard 74 that extends from
the receiver 36 circumferentially about the barrel 56 such that a
user can hold the hand guard 74 of the firearm 30. More
specifically, the hand guard 74 defines a second bore 76 extending
substantially parallel to the longitudinal axis L with the hand
guard 74 coupled to the barrel 56 and the barrel 56 disposed in the
second bore 76. Specifically, the hand guard 74 includes a first
end 78 coupled to the breech 60 and a second end 80 spaced from the
first end 78 along the longitudinal axis L toward the muzzle 62
such that the hand guard 74 is disposed about the barrel 56.
[0046] Turning to FIG. 5, the hand guard 74 includes a projection
82 extending from the second end 80 of the hand guard 74. More
specifically, the hand guard 74 includes a first hand guard portion
84 and a second hand guard portion 86 slidably coupled to the first
hand guard portion 84 with the projection 82 extending from the
second end 80 of the first hand guard portion 84. Details of the
hand guard 74 are further disclosed and claimed in U.S. patent
application Ser. No. ______ filed concurrently with the present
application (attorney docket no. 065111.00145), which is
incorporated herein by reference.
[0047] Referring to FIGS. 2, 3A, 3B, 4 and 6, the firearm 30
includes a bolt carrier 88. The receiver 36 is coupled to the first
end 78 of the hand guard 74 and the breech 60 of the barrel 56. The
bolt carrier 88 is disposed in the third bore 38 of the receiver
36. The bolt carrier 88 is moveable relative to the receiver 36
along the longitudinal axis L between a firing position and a
rearward position. A shield 90 is longitudinally affixed to the
bolt carrier 88 and movable with the bolt carrier 88 as a unit
between the firing and rearward positions along the longitudinal
axis L with the shield 90 blocking the ejection port 40 when in the
firing position and the shield 90 sliding along the inner surface
42 of the third bore 38 away from the ejection port 40 when moving
to the rearward position in conjunction with the bolt carrier 88.
Details of the shield 90 are further disclosed and claimed in U.S.
patent application Ser. No. ______
[0048] filed concurrently with the present application (attorney
docket no. 065111.00130), which is incorporated herein by
reference.
[0049] Specifically, a bolt 92 and a firing pin 94 are carried by
the bolt carrier 88. More specifically, the firing pin 94 is
carried by the bolt 92 and is movable along the longitudinal axis L
relative to the bolt 92. The bolt carrier 88 typically has features
for automatically releasing another live round 32 from the magazine
52 into the barrel chamber 64 as the bolt carrier 88 moves toward
the firing position. As the bolt carrier 88 moves from the rearward
position toward the firing position, the bolt carrier 88 catches or
pushes another live round 32 into the barrel chamber 64 of the
barrel 56. In the firing position, the bolt 92 locks to the breech
60 of the barrel 56 to hold the live round 32 in the barrel chamber
64. The firing components can include the bolt carrier 88, the bolt
92, the firing pin 94, the trigger 54, the hammer and other
components as known to those skilled in the art.
[0050] When the bolt carrier 88 is in the firing position, the
trigger 54 can be pulled to release the hammer, which strikes the
firing pin 94. When the hammer strikes the firing pin 94, the
firing pin 94 strikes the live round 32 to fire the live round 32,
which causes the bullet 34 to move through and out of the first
bore 58. After firing the live round 32, the bolt carrier 88 moves
by gas impingement toward the rearward position and the casing 33,
which is now empty, is expelled from the receiver 36 through the
ejection port 40. The bolt carrier 88 automatically moves toward
the firing position thereby automatically loading another live
round 32 from the magazine 52 into the barrel chamber 64.
[0051] Although the firearm 30 shown in the Figures is of the
semi-automatic type or the automatic type, it is appreciated that
the firearm 30 can also be a single-shot firearm 30 without
departing from the nature of the present invention. A
semi-automatic firearm 30 is one that fires a single live round 32
when the trigger 54 is pulled and thereafter automatically loads
another live round 32. An automatic firearm 30 is one that
individually fires multiple live rounds 32 with a single pull of
the trigger 54 and continues to load and fire live rounds 32 until
the trigger 54 is released. A single-shot firearm 30 requires
manual loading of each live round 32 and fires a single live round
32 when the trigger 54 is pulled.
[0052] Referring to FIGS. 3A and 4, the firing position is defined
as when the bolt carrier 88 abuts the breech 60 of the barrel 56
with or without a live round 32 disposed in the barrel chamber 64
of the barrel 56. Referring to FIG. 6, the rearward position is
defined as when the bolt carrier 88 moves away from the breech 60
of the barrel 56. More specifically, the rearward position is
further defined as when the bolt carrier 88 is spaced from the
breech 60 of the barrel 56 after ejecting a spent casing 33 and
prior to catching another live round 32 to reload into the barrel
chamber 64.
[0053] As best shown in FIGS. 3A and 3B, the bolt carrier 88
defines a hole 96 extending along a bolt axis B and moveable
between an initial position and a mid position. The hole 96 will be
referred to as a carrier hole 96 throughout this description. The
initial position of the bolt carrier 88 is defined as the firing
position as discussed above and is shown in FIGS. 3A and 4. The mid
position of the bolt carrier 88 is further defined as being between
the initial/firing positions and the rearward position, as shown in
FIG. 3B. Specifically, the mid position is defined as when the bolt
carrier 88 is spaced from the breech 60 of the barrel 56 and prior
to ejecting the spent casing 33.
[0054] As used herein, the phrase "along the bolt axis" includes
components and/or movements aligning with the bolt axis B and/or
spaced from and substantially parallel to the bolt axis B.
Specifically, the bolt axis B is substantially parallel to the
longitudinal axis L. More specifically, the bolt axis B aligns with
the longitudinal axis L.
[0055] The bolt 92 is disposed in the carrier hole 96 of the bolt
carrier 88. A cotter pin (not shown) is disposed through the bolt
carrier 88 and the carrier hole 96 transverse to the bolt axis B
for coupling the bolt 92 to the bolt carrier 88 while allowing
independent movement of the bolt 92 relative to the bolt carrier
88. The bolt 92 is movable relative to the bolt axis B between a
first position and a second position during movement of the bolt
carrier 88 between the initial and mid positions. The first
position is shown in FIG. 3A and the second position is shown in
FIG. 3B. The first position of the bolt 92 is defined as when the
bolt 92 is locked into the breech 60 of the barrel 56 prior to
firing the firearm 30. Thus, when the bolt carrier 88 is in the
initial position, the bolt 92 is in the first position, which
occurs prior to firing the firearm 30. The second position of the
bolt 92 is defined as when the bolt 92 rotates about the bolt axis
B and unlocks from the breech 60 of the barrel 56 after firing the
firearm 30 thus allowing the bolt carrier 88 and the bolt 92 to
move to the rearward position. Thus, when the bolt carrier 88 in
the mid position, the bolt 92 is in the second position, which
occurs after firing the firearm 30. As the bolt 92 moves from the
first position to the second position, the bolt 92 rotates to
unlock the bolt 92 from the breech 60 of the barrel 56 for allowing
the bolt carrier 88 and the bolt 92 to continue to move to the
rearward position.
[0056] The bolt carrier 88 further defines a slit 98 having a
cammed surface 100 and further includes a cam pin 102 disposed
through the slit 98 and movable along the slit 98. The cam pin 102
is attached to the bolt 92 such that the bolt 92 rotates as the cam
pin 102 rides along the cammed surface 100 as the bolt 92 moves
between the first and second positions. A biasing member 104 is
disposed between the bolt carrier 88 and the bolt 92 for
continuously biasing the bolt 92 into the second position.
Specifically, the bolt carrier 88 includes a first skirt 106
extending into the carrier hole 96 and spaced from the slit 98 and
the bolt 92 includes a second skirt 108 extending outwardly with
the biasing member 104 abutting the first and second skirts 106,
108 for continuously biasing the bolt 92 into the second position.
The biasing member 104 may be further defined as a spring or any
other suitable biasing member 104 for continuously biasing the bolt
92 into the second position. Utilizing the biasing member 104 with
the bolt 92 eliminates the need for gaskets.
[0057] Referring to FIGS. 4, 5 and 7-9, a front sight 110, a
housing 112 and a piston 114 define a sight assembly for the
firearm 30 having the hand guard 74 disposed about the barrel 56.
In addition, the front sight 110, the housing 112, the piston 114,
the barrel 56 and the hand guard 74 disposed over the barrel 56
define a removable sight system. The front sight 110 is attached to
at least one of the barrel 56 adjacent the muzzle 62 and the second
end 80 of the hand guard 74. Specifically, the front sight 110 is
adapted to be attached to one of the barrel 56 and the hand guard
74. More specifically, the front sight 110 is attached to the
second end 80 of the hand guard 74. The front sight 110 includes a
front side 116 and a back side 118 spaced from each other relative
to the longitudinal axis L with the muzzle 62 defined as a distance
from the front side 116 of the front sight 110 to the distal tip
68.
[0058] The front sight 110 further includes a body 120 and an
extension 122 coupled to the body 120 with the projection 82 of the
hand guard 74 supporting the body 120 of the front sight 110. A
sight pin 124 is disposed through the body 120 and the extension
122 for coupling the extension 122 to the body 120. The extension
122 is movable relative to the sight pin 124 between a down
position preventing use of the extension 122 and an up position
allowing use of the extension 122. The up position is shown in
FIGS. 1, 2 and 4-8 and the down position is shown in FIGS. 14 and
15. Referring back to FIGS. 4, 5 and 7, the body 120 defines an
orifice 126 with a mounting pin 128 removably disposed through the
orifice 126 for selectively detaching the front sight 110 from one
of the barrel 56 and the hand guard 74. The body 120 further
defines a passageway 130 and a hollow 132 spaced from each other,
which will be discussed further below.
[0059] The housing 112 is coupled to the front sight 110 and
defines a chamber 134 extending along a piston axis P. The chamber
134 is referred to as a first chamber 134 throughout this
description. Specifically, the housing 112 is attached to the body
120 of the front sight 110 and the body 120 is attached to the
second end 80 of the hand guard 74. More specifically, the housing
112 and the body 120 are integrally formed to each other. As used
herein, the phrase "along the piston axis" includes components
and/or movements aligning with the piston axis P and/or spaced from
and substantially parallel to the piston axis P. Specifically, the
piston axis P is spaced from and substantially parallel to the
longitudinal axis L. The piston 114 is disposed within the first
chamber 134 of the housing 112 and movable along the piston axis P
between a static position and a displaced position. The static
position is shown in FIGS. 4 and 10 and the displaced position is
shown in FIG. 6.
[0060] Turning to FIG. 5, the housing 112 and the piston 114 are
removable as a unit from one of the barrel 56 and the hand guard
74. More specifically, the front sight 110, the housing 112 and the
piston 114 are removable as a unit for selectively detaching the
unit from one of the barrel 56 and the hand guard 74. The mounting
pin 128 is removably disposed through the orifice 126 of the body
120 for selectively detaching the unit from one of the barrel 56
and the hand guard 74. More specifically, the front sight 110, the
housing 112 and the piston 114 are removable as the unit from the
hand guard 74. The housing 112 and the piston 114 as described
herein are easily retro-fitted into existing firearms 30 and
provide easy serviceability due to the components being removable
as a unit. In addition, the housing 112, the piston 114 and the
front sight 110 as described herein are easily retro-fitted into
existing firearms and provide easy serviceability due to the
components being removable as a unit.
[0061] As best shown in FIG. 10, the first chamber 134 of the
housing 112 defines an inner surface 135 and the piston 114 defines
an outer surface 136 with the outer surface 136 of the piston 114
abutting the inner surface 135 of the housing 112. At least one of
the inner and outer surfaces 135, 136 are plated with a self
lubricating material for reducing friction between the housing 112
and the piston 114 as the piston 114 moves between the static and
displaced positions. The self lubricating material is typically a
thermoplastic material. Suitable thermoplastic materials include a
fluoropolymer material, such as polytetrafluoroethylene, e.g. PTFE.
One example of the thermoplastic material is sold under the brand
name Teflon.RTM. commercially available by DuPont.RTM.. Other
suitable plastics include nylon 12, such as Lauramid.RTM. and
Nyaltron.RTM.; polyoxymethylene; phenolic composites; or
combinations thereof. It is to be appreciated that other self
lubricating materials may also be used for the plating of the inner
surface 135 and/or the outer surface 136. In addition, the
self-lubricating material can include a non-galling material.
[0062] The passageway 130 of the body 120 is spaced from the piston
axis P for routing exhaust gases toward the first chamber 134 of
the housing 112 to move the piston 114 to the displaced position.
Specifically, the tube 72 is coupled to the first port 66 and the
passageway 130 for routing exhaust gases from the barrel 56 to the
piston 114. More specifically, the housing 112 defines a port 138
in fluid communication with the first port 66 and the passageway
130 for routing exhaust gases into the first chamber 134 of the
housing 112 to move the piston 114 from the static position to the
displaced position. The port 138 of the housing 112 is referred to
as a second port 138 throughout this description.
[0063] The housing 112 further defines a bleed-off port 140
transverse to the piston axis P for expelling exhaust gases out of
the first chamber 134 and into the hand guard 74 when the piston
114 is in the displaced position. Specifically, the housing 112
includes a front end 142, a back end 144 and a central portion 146
disposed between the front and back ends 142, 144 with the central
portion 146 defining the second port 138 and the bleed-off port
140. The housing 112 also defines a first diameter and a second
diameter less than the first diameter to define a rim 148
therebetween with the first diameter being complimentary in
configuration to the piston 114 and more specifically complimentary
in configuration to the outer surface 136 of the piston 114.
[0064] The piston 114 defines a first cavity 150 disposed along the
piston axis P for receiving gases routed through the second port
138 to move the piston 114 from the static position to the
displaced position. The piston 114 includes a front surface 152 and
a back surface 154 spaced from each other relative to the piston
axis P with the back surface 154 having a shaft 156 extending along
the piston axis P and the first cavity 150 extending from the front
surface 152 toward the back surface 154. The second diameter of the
housing 112 is complimentary in configuration to the shaft 156.
[0065] The housing 112 defines a plurality of gaps 158 between the
second diameter and the shaft 156 for allowing air and/or debris to
expel out of the first chamber 134 as the piston 114 moves from the
static position to the displaced position. A spring 160 is disposed
around the shaft 156 within the housing 112 for continuously
biasing the piston 114 to the static position. The outer surface
136 of the piston 114 defines a groove 162 with a seal 164 or
gasket disposed in the groove 162 and abutting the inner surface
135 of the housing 112 for preventing exhaust gases from leaking
therethrough. A piston assembly is defined by the housing 112, the
piston 114, the spring 160 and the seal 164.
[0066] The sight assembly further includes a regulator 166
partially disposed in the housing 112 with the piston 114 abutting
the regulator 166 when in the static position (as shown in FIGS. 4
and 10) and spaced from the regulator 166 when in the displaced
position (as shown in FIG. 6). Specifically, the front surface 152
of the piston 114 abuts the regulator 166 when in the static
position. Also referring to FIG. 7, the regulator 166 defines a
plurality of apertures 168 each having a different diameter for
regulating pressure on the piston 114 as exhaust gases move through
one of the apertures 168 toward the piston 114. One of the
apertures 168 is in fluid communication with the second port 138 of
the housing 112 for routing exhaust gases from the barrel 56 to the
first chamber 134 of the housing 112. The regulator 166 further
defines a second cavity 170 disposed along the piston axis P and
transverse to the apertures 168 with the second cavity 170 in fluid
communication with the first cavity 150 and the apertures 168. More
specifically, the second cavity 170 aligns with the first cavity
150 for routing exhaust gases from one of the apertures 168 through
the second cavity 170 and into the first cavity 150 to move the
piston 114 from the static position to the displaced position.
[0067] The regulator 166 also defines a plurality of notches 172
adjacent the apertures 168 with one of the notches 172
substantially parallel to the hollow 132 of the body 120. A gas
block pin 174 is dispose through the hollow 132 and abuts one of
the notches 172 for selectively coupling the regulator 166 to the
housing 112. The gas block pin 174 defines a slot 176 with a
retaining pin 178 engaging the slot 176 for allowing the gas block
pin 174 to move back and forth through the hollow 132 while
remaining coupled to the hollow 132. The gas block pin 174
disengages from one of the notches 172 to allow rotation of the
regulator 166 about the piston axis P and the gas block pin 174
engages another one of the notches 172 such that another one of the
apertures 168 is in fluid communication with the second port 138 of
the housing 112 after rotation of the regulator 166. Specifically,
by rotating the regulator 166, another aperture 168 having another
diameter is in fluid communication with the second port 138 and the
first cavity 150 for regulating or adjusting pressure on the piston
114.
[0068] Turning back to FIGS. 4 and 6, the firearm 30 also includes
a carrier key 180 attached to the bolt carrier 88. The carrier key
180 moves concurrently with the bolt carrier 88 between the firing
and rearward positions with the carrier key 180 extending outwardly
above the bolt carrier 88 and along the piston axis P. The carrier
key 180 prevents rotation of the bolt carrier 88 during movement
between the firing and rearward positions and ensures proper
positioning and operation of the shield 90. A plurality of
fasteners 182 are disposed through the carrier key 180 and into the
bolt carrier 88 to attach the carrier key 180 to the bolt carrier
88 to allow concurrent movement of the carrier key 180 and the bolt
carrier 88.
[0069] A rod 184 is permanently affixed to the carrier key 180 and
extends along the piston axis P to a distal end 186. The piston 114
is adjacent the distal end 186 when in the static position and the
piston 114 engages the distal end 186 when moving to the displaced
position for moving the bolt carrier 88 from the firing position to
the rearward position. The shaft 156 of the piston 114 extends
along the piston axis P for engaging the distal end 186 of the rod
184 when exhaust gases move into the first chamber 134. The shaft
156 defines a depression 188 along the piston axis P and faces the
distal end 186 of the rod 184 to define a striking end for
selectively striking the distal end 186 of the rod 184. As the
piston 114 and the shaft 156 move to the displaced position, the
striking end engages the rod 184 to move the bolt carrier 88 to the
rearward position. Once the piston 114 and the shaft 156 are in the
displaced position, the rod 184 and the bolt carrier 88 continue to
move to the rearward position with the rod 184 becoming spaced from
the striking end.
[0070] The rod 184 is further defined as a solid rod 184. The solid
rod 184 defines a first outer diameter and a second outer diameter
less than the first outer diameter to define a shoulder 190
therebetween. Preferably, the solid rod 184 and the carrier key 180
are integrally formed of a homogeneous metal material with the bolt
carrier 88, the carrier key 180 and the solid rod 184 removable as
a unit from the receiver 36. More specifically, the bolt carrier
88, the bolt 92, the carrier key 180 and the solid rod 184 are
removable as a unit from the receiver 36. The homogenous metal
material of the solid rod 184 and the carrier key 180 is typically
an alloy. Suitable alloys include aluminum and/or iron alloys, e.g.
steel. It is to be appreciated that other metal materials may also
be used for the solid rod 184 and the carrier key 180. The bolt
carrier 88, the bolt 92, the carrier key 180 and the solid rod 184
as described herein are easily retro-fitted into existing firearms
30. In addition, the bolt carrier 88, the bolt 92, the carrier key
180 and the solid rod 184 are easily removed from the firearm 30 by
merely separating the upper and lower receiver portions 44, 46 and
pulling the bolt carrier 88 out of the third bore 38, thus
providing easy serviceability of the components.
[0071] As best shown in FIGS. 4 and 6, the firearm 30 further
includes a first bushing 192 coupled to the hand guard 74 adjacent
the first end 78 and a second bushing 194 coupled to the hand guard
74 adjacent the second end 80. Also referring to FIG. 11, the first
bushing 192 defines a first hole 196 along the piston axis P with
the solid rod 184 continuously disposed through the first hole 196
for guiding the solid rod 184 during movement between the firing
and rearward positions. The first bushing 192 further defines a
plurality of splines 198 spaced from each other within the first
hole 196 for reducing heat buildup and expelling debris as the
solid rod 184 moves back and forth through the first bushing 192
between the firing and rearward positions. The first bushing 192
and the hand guard 74 are integrally formed of a homogeneous metal
material. The homogenous metal material of the first bushing 192
and the hand guard 74 is typically an alloy. Suitable alloys
include aluminum and/or iron alloys, e.g. steel. It is to be
appreciated that other metal materials may also be used for the
first bushing 192 and the hand guard 74.
[0072] The second bushing 194 defines a second hole 200 along the
piston axis P with the solid rod 184 disposed in the second hole
200 when in the firing position and the solid rod 184 spaced from
the second hole 200 when in the rearward position. The second
bushing 194 is further defined as a base 201 slideably supported by
the hand guard 74 and movable between a charging motion and a
forward assist motion. The base 201 is adjacent the back end 144 of
the housing 112. The base 201 is a component of a handle assembly
and details of the handle assembly are further disclosed and
claimed in U.S. patent application Ser. No. ______ filed
concurrently with the present application (attorney docket no.
065111.00129), which is incorporated herein by reference. As best
shown in FIG. 10, the second hole 200 of the second bushing 194
defines a first inner diameter and a second inner diameter less
than the first inner diameter to define a lip 202 therebetween with
the shoulder 190 of the solid rod 184 and the lip 202 engaging each
other when in the firing position.
[0073] As best shown in FIGS. 5, 11 and 12, the firearm 30 includes
a first support 204 coupled to the hand guard 74 adjacent the
second end 80 with the front sight 110 and the housing 112 being
supported by the first support 204. Specifically, the first support
204 and the hand guard 74 are integrally formed of a homogenous
metal material. The homogenous metal material of the first support
204 and the hand guard 74 is typically an alloy. Suitable alloys
include aluminum and/or iron alloys, e.g. steel. It is to be
appreciated that other metal materials may also be used for the
first support 204 and the hand guard 74. Alternatively, the first
support 204 can be attached to the hand guard 74 by fasteners,
welding, adhesive or any other suitable method. The first support
204 includes a seat 206 supporting the housing 112. The first
support 204 further includes the projection 82 extending from the
second end 80 of the hand guard 74 and supporting the body 120 of
the front sight 110. The seat 206 extends more than half way around
the central portion 146 of the housing 112 for supporting the
housing 112. In the most preferred embodiment, the projection 82
includes a pair of fingers 208 with the body 120 disposed between
the fingers 208.
[0074] The first embodiment of the firearm 30 can be a version of
the M4.RTM., including a shorter barrel 56 typically associated
with the M4.RTM., is shown in FIGS. 1-12. A second embodiment of
the firearm 30 can be a version of the M16, including a longer
barrel 210 typically associated with the M16, is shown in FIGS.
13-17. As shown in FIGS. 13-15, both the barrel 210 and a hand
guard 211 are elongated. The back end 144 of the housing 112 is now
spaced a greater distance from the base 201. As such, a shaft 212
of a piston 214 extends out of the housing 112 along the piston
axis P a greater distance toward the distal end 186 of the rod 184
for engaging the distal end 186 as discussed above. In other words,
the shaft 212 of the piston 214 is elongated for allowing a
striking end 216 of the shaft 212 to engage the distal end 186 of
the rod 184.
[0075] As best shown in FIGS. 15-17, a second support 218 and a
third support 220 are utilized for supporting and guiding the
elongated shaft 212 during movement between the static and
displaced positions. The second and third supports 218, 220 are
spaced from each other and coupled to the hand guard 211.
Specifically, the second and third supports 218, 220 and the hand
guard 211 are integrally formed of a homogenous metal material. The
homogenous metal material of the second and third supports 218, 220
and the hand guard 211 is typically an alloy. Suitable alloys
include aluminum and/or iron alloys, e.g. steel. It is to be
appreciated that other metal materials may also be used for the
second and third supports 218, 220 and the hand guard 211.
Alternatively, the second and third supports 218, 220 can be
attached to the hand guard 211 by fasteners, welding, adhesive or
any other suitable method.
[0076] The second support 218 is coupled to the hand guard 211 and
spaced from the first support 204 with the second support 218
defining a first passage 222 along the piston axis P. The shaft 212
is continuously disposed through the first passage 222 during
movement of the piston 214 between the static and displaced
positions. The third support 220 is coupled to the hand guard 211
adjacent the distal end 186 of the rod 184 with the second support
218 disposed between the first and third supports 204, 220.
Specifically, the third support 220 is adjacent the base 201. The
third support 220 defines a second passage 224 along the piston
axis P and the shaft 212 is continuously disposed through the
second passage 224 during movement of the piston 214 between the
static and displaced positions.
[0077] Turning to FIGS. 18-24, a third embodiment of the firearm 30
is disclosed. Specifically, this third embodiment discloses a
piston housing support system for the firearm 30. The piston
housing support system includes the barrel 56 as discussed above
with a slightly modified hand guard 226. The hand guard 226 of this
embodiment includes a first hand guard portion 228 without the
projection 82 as discussed above. The hand guard 226 defines a
second bore 230 extending substantially parallel to the
longitudinal axis L with the hand guard 226 coupled to the barrel
56. Specifically, the hand guard 226 includes a first end 232
coupled to the breech 60 of the barrel 56 and a second end 234
spaced from the first end 232 along the longitudinal axis L toward
the muzzle 62 of the barrel 56 such that the hand guard 226 is
disposed about the barrel 56.
[0078] The piston housing support system further includes a front
sight 236 attached to at least one of the barrel 56 and the hand
guard 226. More specifically, the front sight 236 is attached to
the barrel 56 and includes a front side 238 and a back side 240
spaced from each other relative to the longitudinal axis L.
[0079] Referring to FIGS. 19-21, the piston housing support system
further includes a housing 242 coupled to the front sight 236 and
more specifically, the housing 242 is coupled to the back side 240
of the front sight 236. The housing 242 includes a front end 244, a
back end 246 and a central portion 248 disposed between the front
and back ends 244, 246 with the front end 244 defining a second
port 249. The back end 246 of the housing 242 defines a cutout 250
extending a first predetermined distance toward the front end 244
which will be discussed further below. The housing 242 defines a
chamber 252 extending along a piston axis P between the front and
back ends 244, 246. The chamber 252 is referred to as a first
chamber 252 throughout this description. The piston housing support
system further includes a piston 254 disposed within the first
chamber 252 and movable along the piston axis P between a static
position and a displaced position. A piston assembly includes the
housing 242, the piston 254, a spring and a seal.
[0080] The piston housing support system further includes a cradle
256 disposed between the front sight 236 and the hand guard 226.
The cradle 256 is complementary in configuration to a portion of
the housing 242 for supporting the housing 242 relative to the
front sight 236 and the hand guard 226 when the hand guard 226 is
disposed over the barrel 56 and for allowing removal of the housing
242 from the front sight 236 when the hand guard 226 is removed
from the barrel 56.
[0081] Also referring to FIGS. 22-24, the cradle 256 further
includes a first segment 258 coupled to the front sight 236 for
supporting the housing 242. The first segment 258 includes a first
base 260 engaging the central portion 248 of the housing 242 with
the first base 260 having a pair of base ends 262 and a first
flange 264 extending from one of the base ends 262 and abutting the
front end 244 of the housing 242. The first base 260 further
includes a second flange 266 extending from another one of the base
ends 262 and disposed adjacent the back end 246 of the housing
242.
[0082] The first flange 264 includes an edge 268 extending
outwardly a second predetermined distance toward the back end 246
of the housing 242 with the edge 268 engaging the central portion
248 of the housing 242 for supporting the housing 242. The edge 268
and the first base 260 are substantially parallel to each other
with the housing 242 disposed therebetween with the second flange
266 extending into the cutout 250 of the second end 234. The first
and second predetermined distances of the cutout 250 and the edge
268 respectively are substantially equal for moving the housing 242
into and out of the first base 260. For example, when removing the
housing 242 from the first segment 258, the housing 242 is moved
backward to disengage the edge 268 of the first flange 264 from the
central portion 248 of the housing 242 and the cutout 250 of the
housing 242 moves backward until the housing 242 abuts the second
flange 266, at which time the housing 242 is removable from the
first base 260.
[0083] Referring to FIGS. 19 and 20, the cradle 256 also includes a
second segment 270 formed in the hand guard 226 and spaced
substantially parallel to the first segment 258 for supporting the
housing 242 therebetween. Specifically, the second segment 270 is
formed in the second end 234 of the hand guard 226. More
specifically, the second segment 270 is formed in the second end
234 of the first hand guard portion 228. Once the first hand guard
portion 228 is removed, the second segment 270 is spaced from the
housing 242 and the first segment 258. Spacing the second segment
270 from the first segment 258 allows the housing 242 and the
piston 254 to be removable from the first segment 258 as a unit for
providing easy serviceability of the housing 242 and the piston
254.
[0084] The second segment 270 includes a second base 272 engaging
the central portion 248 of the housing 242 with the second base 272
having a pair of base ends 274 and a third flange 276 extending
from one of the base ends 274 of the second base 272. The third
flange 276 opposes the first flange 264 with the third flange 276
abutting one of the front end 244 of the housing 242 and the first
flange 264 when the hand guard 226 is disposed over the barrel 56.
More specifically, the third flange 276 abuts the first flange 264
with the edge 268 of the first flange 264 abutting the second base
272. The second base 272 further includes a fourth flange 278
extending from another one of the base ends 274 of the second base
272. The fourth flange 278 opposes the second flange 266 with the
fourth flange 278 adjacent the back end 246 of the housing 242 when
the hand guard 226 is disposed over the barrel 56.
[0085] The piston housing support system further includes a support
block 280 attached to the first segment 258 and abutting the barrel
56 for supporting the housing 242 relative to the front sight 236
and the barrel 56. More specifically, the support block 280 is
attached to at least one of the first base 260 and the first flange
264. Most specifically, the support block 280 is attached to the
first flange 264. The support block 280 can be attached to the
first segment 258 by fasteners, welding, adhesive or any other
suitable method. Alternatively, the support block 280 and the first
segment 258 may be integrally formed to each other.
[0086] The piston housing support system also includes a stem 282
attached to the support block 280 and the front sight 236. More
specifically, the stem 282 is pinned to the front sight 236 and the
stem 282 is attached to the support block 280 by any suitable
method, such as fasteners, welding, adhesive, etc. The first
segment 258 and the support block 280 each define a first opening
284 for receiving the stem 282. The stem 282 defines a second
opening 286 in fluid communication with the barrel 56 and the
housing 242 for routing exhaust gases from the barrel 56 into the
first chamber 252 of the housing 242 to move the piston 254 from
the static position to the displaced position. More specifically,
the second opening 286 is in fluid communication with the first
port 66 of the barrel 56 and the second port 249 of the housing
242.
[0087] Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. The
foregoing invention has been described in accordance with the
relevant legal standards; thus, the description is exemplary rather
than limiting in nature. Variations and modifications to the
disclosed embodiment may become apparent to those skilled in the
art and do come within the scope of the invention. Accordingly, the
scope of legal protection afforded this invention can only be
determined by studying the following claims.
* * * * *