U.S. patent application number 13/215696 was filed with the patent office on 2012-04-12 for gas piston system actuator assembly for rifle automatic ejection and reload.
This patent application is currently assigned to BRADHART PRODUCTS, INC.. Invention is credited to Karl Thiele, Stephan Thiele.
Application Number | 20120085226 13/215696 |
Document ID | / |
Family ID | 45924088 |
Filed Date | 2012-04-12 |
United States Patent
Application |
20120085226 |
Kind Code |
A1 |
Thiele; Karl ; et
al. |
April 12, 2012 |
Gas Piston System Actuator Assembly for Rifle Automatic Ejection
and Reload
Abstract
An actuator assembly includes a piston chamber assembly having a
piston chamber and a pin receiving tube extending from the piston
chamber. A gas transfer pin has a first end inserted in the pin
receiving tube and a second end received in a rifle sight alignment
bore. The gas transfer pin has a longitudinal bore in communication
with the piston chamber. A piston member is slidably received in
the piston chamber and includes a piston body with a piston member
extension tube. The piston body includes a raised piston portion
having piston rings, and a ring divider slot positioned between the
piston rings. A rod assembly has a rod engagement end received in a
piston member extension tube receiving bore. A piston clip has an
arm extending through both the rod engagement end and the piston
member extension tube connecting the rod assembly and piston member
and a spiral end.
Inventors: |
Thiele; Karl; (Milford,
MI) ; Thiele; Stephan; (Milford, MI) |
Assignee: |
BRADHART PRODUCTS, INC.
Brighton
MI
|
Family ID: |
45924088 |
Appl. No.: |
13/215696 |
Filed: |
August 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61391188 |
Oct 8, 2010 |
|
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|
Current U.S.
Class: |
89/191.01 |
Current CPC
Class: |
F41A 5/18 20130101 |
Class at
Publication: |
89/191.01 |
International
Class: |
F41A 5/18 20060101
F41A005/18; F41C 7/00 20060101 F41C007/00 |
Claims
1. An actuator assembly for a rifle gas piston ejection and reload
system, comprising: a piston chamber assembly having a piston
chamber and a pin receiving tube integrally extending from an end
of the piston chamber; and a piston member slidably received in the
piston chamber, the piston member including: a piston body having a
raised piston portion including at least two piston rings; and a
piston member extension tube extending axially away from the piston
body.
2. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, further including an operating rod assembly
having a rod engagement end slidably received in an engagement end
receiving bore of the piston member extension tube.
3. The actuator assembly for a rifle gas piston ejection and reload
system of claim 2, further including a piston clip having a clip
arm extending through both the rod engagement end and the piston
member extension tube to releasably connect the operating rod
assembly to the piston member.
4. The actuator assembly for a rifle gas piston ejection and reload
system of claim 3, wherein the piston clip further includes a clip
spiral end having a bend leg defining a continuous bend with
respect to a longitudinal axis of the piston clip.
5. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, further including a ring divider slot positioned
directly between the at least two piston rings.
6. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, further including a gas transfer pin having a
first end slidably inserted in the pin receiving tube and a second
end slidably received in a pin alignment bore of a rifle sight, the
gas transfer pin having a pin longitudinal bore in communication
with the piston chamber, wherein a backpressure from an expanding
gas in the piston chamber during an initial use of the actuator
assembly drives the piston chamber assembly forward with respect to
the initially frictionally seated gas transfer pin until the pin
receiving tube self seats against a flat plate portion of a hand
guard cap.
7. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, wherein the raised piston portion is located at
a free end of the piston body.
8. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, wherein the at least two piston rings of the
piston member include first, second and third piston rings having
first and second ring divider slots between successive ones of the
piston rings.
9. The actuator assembly for a rifle gas piston ejection and reload
system of claim 1, wherein the piston member further includes a
transition portion changing an elevation of the piston member
extension tube with respect to a lower face of the piston body.
10. The actuator assembly for a rifle gas piston ejection and
reload system of claim 1, wherein the raised piston portion is in
sliding contact between an upper inner wall and a lower inner wall
of the piston chamber assembly, thereby creating an upper and a
lower clearance space between the piston body and the upper and
lower inner walls, the upper and lower clearance spaces providing a
throttled gas discharge path to atmosphere from the piston chamber
past the raised piston portion during sliding motion of the piston
member.
11. An actuator assembly for a rifle gas piston ejection and reload
system, comprising: a piston chamber assembly having a piston
chamber and a pin receiving tube homogenously extending from an end
of the piston chamber; a piston member slidably received in the
piston chamber, the piston member including a piston body and a
piston member extension tube extending axially away from the piston
body, the piston body having: a raised piston portion having at
least two piston rings; a ring divider slot positioned directly
between the at least two piston rings; a lower face; and a
transition portion changing an elevation of the piston member
extension tube with respect to the lower face; and an operating rod
assembly having a rod engagement end slidably received in an
engagement end receiving bore of the piston member extension
tube.
12. The actuator assembly for a rifle gas piston ejection and
reload system of claim 11, further including a gas transfer pin
having a first end slidably inserted in the pin receiving tube
during installation of the actuator assembly and a second end
slidably received in a pin alignment bore of a rifle sight.
13. The actuator assembly for a rifle gas piston ejection and
reload system of claim 12, wherein the gas transfer pin includes a
pin longitudinal bore in communication with the piston chamber.
14. The actuator assembly for a rifle gas piston ejection and
reload system of claim 12, wherein backpressure from expanding gas
in the piston chamber initially drives the piston chamber assembly
forward with respect to the initially frictionally seated gas
transfer pin until the pin receiving tube self seats against a flat
plate portion of a hand guard cap, thereafter providing
longitudinal and latitudinal support and stability at a connection
of the gas transfer pin receiving tube and the gas transfer
pin.
15. The actuator assembly for a rifle gas piston ejection and
reload system of claim 14, wherein an axial gap of approximately
0.051 to 0.089 cm (0.020 to 0.035 in) is originally present between
the hand guard cap and an end of the gas transfer pin receiving
tube.
16. The actuator assembly for a rifle gas piston ejection and
reload system of claim 11, further including a piston clip having a
clip arm extending through both the rod engagement end and the
piston member extension tube to releasably connect the operating
rod assembly to the piston member.
17. The actuator assembly for a rifle gas piston ejection and
reload system of claim 16, wherein the piston clip further includes
a clip spiral end having a bend leg including at least one bend
bending at least 120 degrees with respect to a longitudinal axis of
piston clip.
18. An actuator assembly for a rifle gas piston ejection and reload
system, comprising: a piston chamber assembly having a piston
chamber and a pin receiving tube homogenously extending from an end
of the piston chamber; a piston member slidably received in the
piston chamber, the piston member including a piston body and a
piston member extension tube extending axially away from the piston
body, the piston body having: a raised piston portion having at
least two piston rings; and a ring divider slot positioned directly
between the at least two piston rings; an operating rod assembly
having a rod engagement end slidably received in an engagement end
receiving bore of the piston member extension tube; and a piston
clip having a clip arm extending through both the rod engagement
end and the piston member extension tube to releasably connect the
operating rod assembly to the piston member and a clip spiral end
having a bend leg defining a continuous bend of at least 120
degrees with respect to a longitudinal axis of the piston clip.
19. The actuator assembly for a rifle gas piston ejection and
reload system of claim 18, further including gas flow passage
providing for gas communication between the piston chamber and a
receiving tube bore separated by an end wall.
20. The actuator assembly for a rifle gas piston ejection and
reload system of claim 19, wherein a passage diameter of the gas
flow passage is smaller than an opening of the piston chamber and a
diameter of the receiving tube bore.
21. The actuator assembly for a rifle gas piston ejection and
reload system of claim 18, further including an actuator assembly
releasably pinned using the piston clip to the piston member, the
actuator assembly having: a bushing with a bushing bore; the
bushing bore sized to be slidingly received about an outer diameter
of a solid first rod member; and a second rod member having the
first rod member releasably connected to the second rod member
using a rod connecting member.
22. The actuator assembly for a rifle gas piston ejection and
reload system of claim 21, wherein a piston chamber inner length is
predetermined based on a total axial throw required for the
actuator assembly and thereby based on a maximum sliding
displacement of the piston member.
23. The actuator assembly for a rifle gas piston ejection and
reload system of claim 22, wherein the piston chamber inner length
is approximately 3.15 cm (1.24 in).
24. The actuator assembly for a rifle gas piston ejection and
reload system of claim 18, further including a gas transfer pin
having a first end slidably received in the pin receiving tube and
a second end slidably received in a pin alignment bore of a rifle
sight, the gas transfer pin having a pin longitudinal bore in
communication with the piston chamber.
25. The actuator assembly for a rifle gas piston ejection and
reload system of claim 24, wherein an installed position of the
actuator assembly with respect to a front sight and a barrel of a
rifle is defined by: a sliding contact between the first rod member
and an outer surface of a barrel nut; and a transition portion
upper face of the piston member being positioned at a spacing
dimension with respect to a barrel longitudinal axis of the
barrel.
26. The actuator assembly for a rifle gas piston ejection and
reload system of claim 24, further including: a first end of the
gas transfer pin being slidably received in a gas transfer pin
receiving tube of the piston chamber assembly; and a second end of
the gas transfer pin being slidably received in a pin alignment
bore extending partially through the front sight and axis parallel
with the barrel longitudinal axis; the gas transfer pin being
further axially restrained within the pin alignment bore by
extension of a retention pin through a retention pin mating bore
opening into the pin alignment bore.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/391,188, filed on Oct. 8, 2010. The entire
disclosure of the above application is incorporated herein by
reference.
FIELD
[0002] The present disclosure relates to gas piston automatic
ejection and reload operating systems for rifles.
BACKGROUND
[0003] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0004] Automatic and semi-automatically operated rifles, such as
the M16, also known as the AR15 automatic rifle, can include a gas
operating system which uses a portion of the gas pressure generated
during a firing operation to automatically eject a spent cartridge
and in a continuous operation to load a new shell in the chamber
for firing. Known gas operated systems for this purpose use a
combination of a cylinder which receives gas pressure from a bypass
line opening into the rifle barrel, and a piston slidably displaced
in the cylinder by the gas pressure to operate an ejection and
reload device.
[0005] Because of internal geometries of known piston and cylinder
designs, these systems are subject to rapid buildup of gas residue
such as burned gun powder. This buildup causes incomplete
displacement or complete jamming of the piston which inhibits
proper ejection of a spent cartridge and reloading of a new shell.
Frequent cleaning of these systems can be required after as few as
200 rounds or less of operation.
SUMMARY
[0006] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0007] According to several embodiments, an actuator assembly for a
weapon gas piston ejection and reload system includes a piston
chamber assembly having a kidney shaped piston chamber and a pin
receiving tube homogenously extending from an end of the piston
chamber. A gas transfer pin has a first end slidably inserted in
the pin receiving tube and a second end slidably received in a pin
alignment bore of a rifle sight. The gas transfer pin has a pin
longitudinal bore in communication with the piston chamber. A
piston member is slidably received in the piston chamber and
includes a piston body and a piston member extension tube extending
axially away from the piston body. The piston body includes a
raised piston portion having at least two piston rings; and a ring
divider slot positioned directly between the at least two piston
rings. An operating rod assembly has a rod engagement end slidably
received in an engagement end receiving bore of the piston member
extension tube. A piston clip has a clip arm extending through both
the rod engagement end and the piston member extension tube to
releasably connect the operating rod assembly to the piston member,
and a clip spiral end having a bend leg bending greater than 120
degrees with respect to a longitudinal axis of piston clip.
[0008] According to further embodiments, the at least two piston
rings of the piston member include first, second and third piston
rings having first and second ring divider slots between successive
ones of the piston rings. The piston member further includes a
transition portion changing an elevation of the piston member
extension tube with respect to a lower face of the piston body.
[0009] According to still other embodiments, the gas transfer pin
is further slidable within the pin receiving tube during
installation of the actuator assembly in the weapon to accommodate
dimensional tolerances differing between differing ones of the
weapon.
[0010] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0011] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0012] FIG. 1 is a right side elevational view of a rifle having a
gas piston system actuator assembly of the present disclosure;
[0013] FIG. 2 is a left side elevational view of the rifle of FIG.
1;
[0014] FIG. 3 is a right perspective view of a receiver, rifle
barrel and actuator assembly of the present disclosure after
removal of component parts and hand guards from the rifle of FIG.
1;
[0015] FIG. 4 is an exploded assembly view of the receiver, rifle
barrel and actuator assembly of FIG. 3;
[0016] FIG. 5 is a top plan view of the actuator assembly of FIG. 3
proximate a bolt carrier;
[0017] FIG. 6 is a side elevational view of the assembly of FIG.
5;
[0018] FIG. 7 is a top plan view of the actuator assembly of FIG.
3;
[0019] FIG. 8 is a side elevational view of the actuator assembly
of FIG. 7;
[0020] FIG. 9 is an end elevational view of the actuator assembly
of FIG. 7;
[0021] FIG. 10 is a cross sectional side elevational view taken at
section 10 of FIG. 1;
[0022] FIG. 11 is a cross sectional end elevational view taken at
section 11 of FIG. 10;
[0023] FIG. 12 is a cross sectional end elevational view taken at
section 12 of FIG. 10;
[0024] FIG. 13 is a cross sectional side elevational view of area
13 of FIG. 10 showing the actuator assembly in a fully retracted
position;
[0025] FIG. 14 is a cross sectional side elevational view modified
from FIG. 13 showing the actuator assembly in a fully extended
operating position;
[0026] FIG. 15 is a top plan view of a piston chamber assembly of
the present disclosure;
[0027] FIG. 16 is an end elevational view of the piston chamber
assembly of FIG. 15;
[0028] FIG. 17 is a cross sectional side elevational view taken at
section 17 of FIG. 16;
[0029] FIG. 18 is a top plan view of an alternate embodiment piston
member of the present disclosure;
[0030] FIG. 19 is a side elevational view of the piston member of
FIG. 18;
[0031] FIG. 20 is a side elevational view of a gas transfer pin of
the present disclosure;
[0032] FIG. 21 is a bottom plan view of the gas transfer pin of
FIG. 20;
[0033] FIG. 22 is a cross sectional side elevational view taken at
section 22 of FIG. 20; and
[0034] FIG. 23 is top perspective view of a portion of the actuator
assembly and piston clip of the present disclosure.
[0035] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0036] Example embodiments will now be described more fully with
reference to the accompanying drawings. Example embodiments are
provided so that this disclosure will be thorough, and will fully
convey the scope to those who are skilled in the art. Numerous
specific details are set forth such as examples of specific
components, devices, and methods, to provide a thorough
understanding of embodiments of the present disclosure. It will be
apparent to those skilled in the art that specific details need not
be employed, that example embodiments may be embodied in many
different forms and that neither should be construed to limit the
scope of the disclosure. In some example embodiments, well-known
processes, well-known device structures, and well-known
technologies are not described in detail.
[0037] The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms "a," "an," and "the"
may be intended to include the plural forms as well, unless the
context clearly indicates otherwise. The terms "comprises,"
"comprising," "including," and "having," are inclusive and
therefore specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. The
method steps, processes, and operations described herein are not to
be construed as necessarily requiring their performance in the
particular order discussed or illustrated, unless specifically
identified as an order of performance. It is also to be understood
that additional or alternative steps may be employed.
[0038] When an element or layer is referred to as being "on,"
"engaged to," "connected to," or "coupled to" another element or
layer, it may be directly on, engaged, connected or coupled to the
other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly engaged to," "directly connected to," or
"directly coupled to" another element or layer, there may be no
intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in
a like fashion (e.g., "between" versus "directly between,"
"adjacent" versus "directly adjacent," etc.). As used herein, the
term "and/or" includes any and all combinations of one or more of
the associated listed items.
[0039] Although the terms first, second, third, etc. may be used
herein to describe various elements, components, regions, layers
and/or sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
[0040] Spatially relative terms, such as "inner," "outer,"
"beneath," "below," "lower," "above," "upper," and the like, may be
used herein for ease of description to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the figures. Spatially relative terms may be
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the example term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
[0041] Referring to FIG. 1, a rifle 10, which according to several
embodiments represents an M16 (also commonly known as an AR15
assault rifle), is depicted. Rifle 10 includes a stock 12 connected
to a receiver 14. The receiver 14 includes a hand grip 16, a
trigger assembly 18, and a magazine receiver 20 for slidably
receiving a magazine 22. An upper receiver portion 24 commonly acts
as a carrying handle as well as a rear sight for rifle 10. An
ejection port 26 provides for ejection of spent shell casings as
rifle 10 is fired. A barrel 28 is connected to receiver 14 having a
hand guard assembly 30 covering a portion of barrel 28 and used for
manually supporting barrel 28 during firing. A front sight 32 is
releasably connected to barrel 28 and establishes a forward support
point for hand guard assembly 30. A flash suppressor 34 can also be
commonly added to a free end of barrel 28.
[0042] Referring to FIG. 2, a left hand side of rifle 10 provides
for a selector switch 36, which can be used to manually select
between manual individual-round and automatic firing operations.
The front sight 32 is connected to barrel 28 using first and second
sight mounting legs 38, 40, which extend at least partially about
the perimeter of barrel 28. Positioned directly between second
sight mounting leg 40 and the forward end of hand guard assembly 30
is a hand guard cap 42. A delta ring 44 is used to connect barrel
28 to receiver 14. Delta ring 44 also provides for a rear
connection or support point for hand guard assembly 30.
[0043] Referring to FIG. 3, and again to FIGS. 1 and 2, the hand
guard assembly 30 is shown removed for clarity. An actuator
assembly 46 of the present disclosure is shown in its installed
position having a portion in contact with delta ring 44. Actuator
assembly 46 is slidably positioned to contact receiver 14 and is
connected to front sight 32 through hand guard cap 42. Actuator
assembly 46 provides a passageway for a portion of the gas
discharged during the firing operation to be returned toward
receiver 14 and converted to a mechanical force to both eject a
spent cartridge from receiver 14 as well as to reload a new
shell.
[0044] Referring to FIG. 4, component parts of actuator assembly 46
include a bushing 48 having a bushing bore 50 sized to be slidingly
received about an outer diameter "A" of a first rod member 52.
First rod member 52 is a solid rod of a metal such as steel or
aluminum. First rod member 52 is releasably connected to a second
rod member 54 also made of a metal such as steel or aluminum using
a rod connecting member 56. The combination of first and second rod
members 52, 54 and rod connecting member 56 forms an operating rod
assembly 58. Operating rod assembly 58 is in turn releasably pinned
to a piston member 60.
[0045] Piston member 60 includes a piston body 62 having a raised
piston portion 64 at a free end thereof. Raised piston portion 64,
as well as piston body 62, is kidney-shaped to be slidably received
within a kidney-shaped piston chamber 66 of a piston chamber
assembly 68. Operating rod assembly 58 is releasably connected to
piston member 60 as follows. A piston clip 70 of a steel material
such as spring steel is used to releasably join operating rod
assembly 58 to piston member 60. First, a second rod engagement end
72 of second rod member 54 has a diameter which is sized to be
slidably received within an engagement end receiving bore 74 of a
piston member extension tube 76 extending axially from piston
member 60. Second rod engagement end 72 is slidably disposed within
engagement end receiving bore 74 until a contact portion 77 of
second rod member 54 contacts an end face of piston member
extension tube 76. At this time, a first clip receiving bore 78
created through second rod engagement end 72 is co-axially aligned
with a second clip receiving bore 80 transversely created through
piston member extension tube 76. A clip arm 82 of piston clip 70 is
slidably inserted through both second clip receiving bore 80 and
simultaneously through first clip receiving bore 78 to releasably
couple operating rod assembly 58 to piston member 60. By rotating
piston clip 70 with respect to a longitudinal axis of clip arm 82,
a clip spiral end 84 can be engaged to the outer perimeter of
second rod member 54 preventing removal of clip arm 82 and thereby
acting as a locking device to releasably lock piston clip 70 onto
second rod member 54.
[0046] Once piston member 60 is releasably connected to operating
rod assembly 58 using piston clip 70, a gas transfer pin 86 has a
first end slidably inserted into a gas transfer pin receiving tube
88 of piston chamber assembly 68 until friction forces restrict
further insertion. To retain gas transfer pin 86 and piston chamber
assembly 68, a retention pin 90 is frictionally received in a
retention pin bore 92 proximate a free end of gas transfer pin 86,
which will be described in better detail with reference to FIG. 10.
The raised piston portion 64 and piston body 62 of piston chamber
assembly 68 are then slidably inserted into the piston chamber
66.
[0047] With actuator assembly 46 thus assembled, a bolt carrier 94
is slidably inserted into a barrel port 96 of receiver 14 such that
a chamber 97 of receiver 14 is aligned with a shell port 98 of bolt
carrier 94. With bolt carrier 94 thus positioned, an impactor end
100 of first rod member 52 is co-axially aligned such that impactor
end 100 can strike an impact member 102 of bolt carrier 94 to
axially displace bolt carrier 94 within receiver 14. A threaded
bore 104 of a barrel nut 106 connected to barrel 28 is threadably
connected to a plurality of male threads 108 of delta ring 44 to
threadably connect barrel 28 using threaded bore 104 to delta ring
44.
[0048] Referring to FIG. 5 and again to FIG. 4, impact member 102
includes an impact face 114. Bushing 48 includes a bushing end face
115 such that an axial position of bushing 48 along first rod
member 52 positions bushing end face 115 to act as a stop for axial
travel of operating rod assembly 58 and piston member 60. First and
second rod members 52, 54 are solid circular-shaped rods or if
hollow have wall thicknesses selected to minimize axial bending as
operating rod assembly 58 axially displaces bolt carrier 94. The
piston clip 70 is shown with clip arm in its inserted position and
clip spiral end 84 in frictional contact with second rod member 54.
Contact portion 77 of second rod member 54 can have at least one
flat surface providing for application of a tool such as a wrench
to rotate second rod member 54 to co-axially align first and second
clip receiving bores 78, 80 permitting installation of clip arm 82
of piston clip 70.
[0049] Referring to FIG. 6 and again to FIG. 1, in order to
accommodate offset dimensions of rifle 10, a pin longitudinal axis
116 of gas transfer pin 86 is offset by an axial offset dimension
"B" with respect to a first rod longitudinal axis 118 of first rod
member 52. Piston member 60 therefore includes a transition portion
120, which provides for the axial offset dimension "B".
[0050] Referring to FIG. 7 and again to FIG. 4, actuator assembly
46, having piston member 60 fully slidably received within piston
chamber assembly 68, provides for an actuator assembly minimum
length "C". It is also noted that gas transfer pin 86, which is
slidably received in a pin insertion direction "D" within gas
transfer pin receiving tube 88, can extend outwardly with respect
to gas transfer pin receiving tube 88 to varying lengths upon
initial installation. This variable extension length (VEL) is
provided so that when actuator assembly 46 is assembled into the
rifle, the actual dimensional tolerances for the specific rifle are
accommodated by further insertion of gas transfer pin 86 into gas
transfer pin receiving tube 88 as the barrel 28 is fixed to rifle
10.
[0051] Referring to FIG. 8 and again to FIG. 1, when piston member
60 is fully slidably received within piston chamber assembly 68, an
actuator assembly maximum height "E" is defined between a
transition portion upper face 122 of piston member 60 and a lower
face 124 of piston chamber assembly 68. Lower face 124 can also be
co-linearly aligned with a similar lower face of transition portion
120. The actuator assembly maximum height "E" is maintained to
provide for interior clearance and motion between piston member 60
and piston chamber assembly 68 when hand guard assembly 30 is
installed on rifle 10.
[0052] Referring to FIG. 9, an actuator assembly maximum width "F"
is defined by outside facing walls of piston chamber assembly 68.
Also visible in FIG. 9 is that lower face 124 is defined at two
locations of piston chamber assembly 68 due to the kidney shape of
piston chamber assembly 68.
[0053] Referring to FIG. 10 and again to FIGS. 3 and 4, actuator
assembly 46 is shown in its installed position with respect to
front sight 32 and barrel 28. The installed position is defined by
sliding contact between first rod member 52 and an outer surface of
barrel nut 106. In the installed position, the transition portion
upper face 122 of piston member 60 is positioned at a spacing
dimension "G" with respect to a barrel longitudinal axis 128 of
barrel 28. The gas transfer pin 86 has a first end 125 slidably
received in gas transfer pin receiving tube 88 of piston chamber
assembly 68, and a second end 126 slidably received in a pin
alignment bore 127 extending partially through front sight 32 and
axis parallel with a barrel longitudinal axis 128. Raised piston
portion 64, at its maximum inserted position in piston chamber 66
of piston chamber assembly 68, minimizes a free volume of piston
chamber 66. An alignment height "H" is also established in this
position between an upper surface of first rod member 52 and barrel
longitudinal axis 128 allowing sliding motion of first rod member
52. Gas transfer pin 86 is further axially restrained within pin
alignment bore 127 by extension of retention pin 90 through a
corresponding retention pin mating bore 129 created through front
sight 32 and opening into pin alignment bore 127.
[0054] Referring to FIG. 11 and again to FIG. 10, the spacing
dimension "G" between piston member extension tube 76 and barrel
longitudinal axis 128 maintains clearance between piston member
extension tube 76 and barrel 28. Clearance is therefore provided at
a minimum diameter of barrel 28 shown, as well as at a maximum
barrel diameter shown in FIG. 10 proximate to barrel nut 106.
[0055] Referring to FIG. 12, the kidney shape of piston body 62
includes an inner arc surface "J" whose radius starts at the center
defining the diameter of barrel 28 such that continuous clearance
is maintained to barrel 28 throughout the inner arc surface "J" of
piston body 62. A minimum outer diameter "K" of barrel 28 is shown.
The kidney shape of piston body 62 allows the inner arc surface "J"
to be positioned at the closest point of approach while also
allowing sliding motion of piston body 62 in a direction into and
out of the page for FIG. 12.
[0056] Referring to FIG. 13, operation of actuator assembly 46 is
accomplished as follows. Raised piston portion 64 is in sliding
contact between upper and lower inner walls 130, 132 of piston
chamber assembly 68. Upper and lower clearance spaces 134, 136 are
maintained between piston body 62 and upper and lower inner walls
130, 132. Upper and lower clearance spaces 134, 136 provide a gas
discharge path to atmosphere from piston chamber 66 past raised
piston portion 64 during sliding motion of piston member 60. This
provides for a throttling effect to reduce a pressure within piston
chamber 66 over time. The pressure in piston chamber 66 is normally
equal to atmospheric pressure until the rifle is fired. A biasing
force provided by a spring (not shown) is therefore provided to
normally bias piston member 60 in a piston return direction "M" to
hold piston member 60 in direct contact with piston chamber
assembly 68.
[0057] A pin longitudinal bore 138 extending axially within gas
transfer pin 86 opens into piston chamber 66. A gas entrance bore
140 created in gas transfer pin 86 is oriented perpendicular with
respect to and opens into pin longitudinal bore 138, and is aligned
to open into a gas transfer chamber 142. Gas transfer chamber 142
is created in a leg portion 144 of second sight mounting leg 40.
Leg portion 144 is in direct contact with an outer perimeter
portion of barrel 28. Front sight 32 is positioned on barrel 28 to
align transfer chamber 142 with an exhaust gas bypass port 146
which is oriented transverse to barrel longitudinal axis 128 and
opens into a rifle bore 148. As a shell 150 travels through rifle
bore 148 of barrel 28 to the right as viewed in FIG. 13, shell 150
is propelled by a gas pressure "P.sub.1" in rifle bore 148. As
shell 150 passes the entrance into exhaust gas bypass port 146, a
portion of the gas pressure "P.sub.1" in rifle bore 148, shown as
pressure "P.sub.2", is directed into exhaust gas bypass port 146 in
a gas inlet flow direction "L". This pressurized gas flows from
exhaust gas bypass port 146 into gas transfer chamber 142, through
gas entrance bore 140 and pin longitudinal bore 138, and into
piston chamber 66. Gas pressure "P.sub.2" in piston chamber 66 acts
on raised piston portion 64 to force piston member 60 in a piston
operating direction "N".
[0058] With continuing reference to FIG. 13 and again to FIG. 4,
the piston chamber assembly 68 is substantially fixed in position
by frictional engagement with gas transfer pin 86 which is
frictionally engaged with the bore wall of pin alignment bore 127.
An axial gap of approximately 0.051 to 0.089 cm (0.020 to 0.035 in)
is originally present between hand guard cap 42 and an end 149 of
gas transfer pin receiving tube 88 prior to firing a first round or
shell 150. After approximately 2 to 4 rounds are fired,
backpressure from the expanding gas in piston chamber 66 drives
piston chamber assembly 68 forward in the piston return direction
"M" with respect to the frictionally seated and pinned gas transfer
pin 86 until gas transfer pin receiving tube 88 self seats against
a flat plate portion 151 of hand guard cap 42. This "self seating"
action provides subsequent longitudinal and latitudinal support and
stability at the connection of gas transfer pin receiving tube 88
and gas transfer pin 86, enhances operation of the system including
actuator assembly 46 in general, and minimizes stress risers at the
junction of gas transfer pin 86 and flat plate portion 151.
[0059] Referring to FIG. 14 and again to FIG. 13, both piston
member 60 and operating rod assembly 58 are shown after their full
displacement in the piston operating direction "N". At this time,
the pressure within piston chamber 66 is reduced to a pressure
"P.sub.3", which is less than pressure "P.sub.2" due to gas
expansion within piston chamber 66, as well as escape of a portion
of the gas via upper and lower clearance spaces 134, 136 during
sliding motion of raised piston portion 64. With further reference
again to FIG. 4, the displacement of operating rod assembly 58 in
the piston operating direction "N" produces an impact between
impactor end 100 of first rod member 52 and impact member 102 of
bolt carrier 94. Axial displacement of bolt carrier 94 in the
piston operating direction "N" acts to eject a spent cartridge from
shell port 98 via chamber 97 of receiver 14. A new shell is then
automatically loaded into shell port 98 via a spring biasing force
provided in the magazine as well known.
[0060] After shell 150 exits rifle bore 148, the pressure within
rifle bore 148 quickly returns to atmospheric pressure, which also
allows a remaining portion of the gas within piston chamber 66 to
return through an opposite path and via exhaust gas bypass port 146
to equalize with atmospheric pressure in rifle bore 148. At this
time, a biasing force acting on operating rod assembly 58 via bolt
carrier 94 returns both operating rod assembly 58 and piston member
60 to the fully extended position shown in FIG. 13. The actuator
assembly 46 repositioned to the fully extended position shown in
FIG. 13 is thereafter ready for a next firing operation.
[0061] Referring to FIG. 15, according to several embodiments,
piston chamber assembly 68 is a one-piece homogenous body having a
kidney shaped chamber perimeter surface 152. The gas transfer pin
receiving tube 88 homogeneously extending from piston chamber
assembly 68 is substantially circular having a receiving tube
diameter "0".
[0062] Referring to FIG. 16, the kidney shape of piston chamber
assembly 68 is more clearly visible having a curved chamber upper
outer wall 154 and a curved chamber lower outer wall 156, which
correspond in curvature to the upper and lower inner walls 130,
132. Each of the upper and lower inner walls 130, 132, as well as
the chamber upper and lower outer walls 154, 156, share a common
center of curvature. The opposed sides of piston chamber assembly
68 are mirror image curved surfaces, including a chamber side inner
wall 158 and a chamber side outer wall 160 shown as the right hand
sides as viewed in FIG. 16, which are duplicated on the left hand
side. A gas flow passage 162 is created through an end wall 163
separating piston chamber 66 from gas transfer pin receiving tube
88. The common center of curvature is located at a distance "R"
with respect to an axial centerline of gas flow passage 162 and an
exemplary one of the radii "S" defining upper inner wall 130
extending from the center of curvature is shown.
[0063] Referring to FIG. 17 and again to FIG. 4, gas flow passage
162 provides for gas communication between piston chamber 66 and a
receiving tube bore 164 separated by end wall 163. Because gas flow
passage 162 is intended only for gas flow, a passage diameter "T"
of gas flow passage 162 is smaller than the opening of piston
chamber 66 and the diameter of receiving tube bore 164 which are
sized to slidably receive piston member 60 and gas transfer pin 86
respectfully. A piston chamber inner length "U" of piston chamber
66 is predetermined based on the total axial throw required for
actuator assembly 46 and therefore the maximum sliding displacement
of piston member 60. According to several embodiments, piston
chamber inner length "U" can be 3.15 cm (1.24 inches) when applied
to an M16 rifle, but can vary at the discretion of the
manufacturer.
[0064] Referring to FIG. 18 and again to FIGS. 4 and 6, an
alternate embodiment piston member 166 functions to create a
tortuous path for gas within piston chamber 66 escaping past the
piston member 166. Piston member 166 includes a second clip
receiving bore 168 which is substantially identical to piston
member extension tube 76. A transition portion 170 is substantially
identical to transition portion 120. A piston body 172, similar to
piston body 62, occupies a smaller space envelope than a raised
piston portion 174. Raised piston portion 174 is modified from
raised piston portion 64 and includes at least two piston rings,
and according to several embodiments includes first, second and
third piston rings 176, 178, 180. The first, second, and third
piston rings 176, 178, 180 are positioned proximate to a piston end
wall 182.
[0065] Referring to FIG. 19 and again to FIG. 4, successive ones of
the piston rings are separated by a ring divider slot, which can
include first and second ring divider slots 188, 190. The purpose
for separating the piston rings using the ring divider slots is to
increase the turbulence in the gas flowing past the first, second
and third piston rings 176, 178, 180, thereby further restricting
gas flow escaping to atmosphere and maximizing the pressure
available for displacement of piston member 166. Piston member 166
is connected to operating rod assembly 58 using piston clip 70 in
the same manner as previously described with respect to piston
member 60.
[0066] Referring to FIG. 20 and again to FIG. 7, gas transfer pin
86 includes a pin length "V", which is predetermined to provide
variable extension length (VEL) when inserted into gas transfer pin
receiving tube 88 of piston chamber assembly 68. According to
several embodiments, pin length "V" is 4.249 cm (1.673 inches) when
used in an M16 rifle. To provide for ease of installation of gas
transfer pin 86, a first and second chamfered end 192, 194 are
provided at opposite ends. A recessed area 196 is spatially
separated from retention pin bore 92. Recessed area 196 has a
radius defining a recess arc of curvature "X". A retention pin bore
diameter "W" of retention pin bore 92 according to several
embodiments is 0.201 cm (0.0790 inches) when used in an M16 rifle.
A pin diameter "Y" of gas transfer pin 86 is controlled to a
tolerance varying within multiple ten thousandths of an inch to
permit the gas transfer pin 86 to be slidably received and then
frictionally retained within gas transfer pin receiving tube
88.
[0067] Referring to FIG. 21, pin gas entrance bore 140 defines a
substantially oval shape when created through recessed area 196. A
circumferential slot 198 extends about a perimeter of gas transfer
pin 86.
[0068] Referring to FIG. 22, pin longitudinal bore 138 of gas
transfer pin 86 has a bore diameter "Z". According to several
embodiments, bore diameter "Z" is approximately 0.178 cm (0.070
inches) when used in an M16 rifle.
[0069] Referring to FIG. 23, piston clip 70 includes a bend 200 of
approximately 90 degrees at the junction with clip arm 82 to align
clip arm 82 for perpendicular positioning with respect to piston
member extension tube 76 and second rod engagement end 72 (not
visible in this view) of second rod member 54. No bends less than
120 degrees with respect to a longitudinal axis of piston clip 70
are used at a continuous bend clip spiral end 84 so that axial
forces from movement of second rod member 54 do not create stress
risers in clip spiral end 84. Clip spiral end 84 includes at least
one bend leg 202 having a bend angle greater than 120 degrees, and
according to several embodiments can further include a second bend
leg 204 having a bend angle greater than 120 degrees.
[0070] Features and dimensions of the actuator assembly 46 of the
present disclosure are described herein with respect to use with an
M16 rifle. It should be evident these features and dimensions are
not limited to the M16 rifle and can be varied to use an actuator
assembly of the present disclosure in other rifles or weapon
systems.
[0071] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
* * * * *