U.S. patent application number 11/505689 was filed with the patent office on 2010-07-29 for method and apparatus for an action system for a firearm.
This patent application is currently assigned to SNAKE RIVER MACHINE, INC.. Invention is credited to Jeffrey Hajjar, Warren Stockton.
Application Number | 20100186581 11/505689 |
Document ID | / |
Family ID | 42353082 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100186581 |
Kind Code |
A1 |
Hajjar; Jeffrey ; et
al. |
July 29, 2010 |
METHOD AND APPARATUS FOR AN ACTION SYSTEM FOR A FIREARM
Abstract
A method and apparatus providing an action system for a
semi-automatic shotgun including a receiver having an ejection port
for expelling an empty cartridge of a fired projectile. The action
system includes a bolt attached to a bolt carrier, wherein the bolt
and the bolt carrier are movable within the receiver and
substantially parallel to a longitudinal axis. A surface is
attached to at least the bolt carrier or the receiver, and a roller
is positioned rearward of the ejection port and proximate the
surface, wherein a resistance is provided to rearward movement of
at least the bolt or bolt carrier.
Inventors: |
Hajjar; Jeffrey; (Boise,
ID) ; Stockton; Warren; (Meridian, ID) |
Correspondence
Address: |
FACTOR & LAKE, LTD
1327 W. WASHINGTON BLVD., SUITE 5G/H
CHICAGO
IL
60607
US
|
Assignee: |
SNAKE RIVER MACHINE, INC.
|
Family ID: |
42353082 |
Appl. No.: |
11/505689 |
Filed: |
August 17, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11003073 |
Dec 3, 2004 |
7299737 |
|
|
11505689 |
|
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60526540 |
Dec 3, 2003 |
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Current U.S.
Class: |
89/188 ;
89/180 |
Current CPC
Class: |
F41A 3/46 20130101 |
Class at
Publication: |
89/188 ;
89/180 |
International
Class: |
F41A 3/26 20060101
F41A003/26 |
Claims
1. A roller delayed blowback action system for a semi-automatic
shotgun having a receiver including an ejection port for expelling
an empty cartridge of a fired projectile, the roller delayed
blowback action system comprising: the receiver including a pair of
inserts--a first insert and a second insert--extending within the
receiver; a bolt carrier including a third insert, the bolt carrier
being operatively attached to a bolt, wherein the bolt and the bolt
carrier being movable within the receiver and substantially
parallel to a longitudinal axis; a pair of rollers--a first roller
and a second roller--positioned rearward of the ejection port, the
pair of rollers being substantially contained within the bolt and
proximate the third insert, the first roller being proximate the
first insert and the third insert and the second roller being
proximate the second insert and the third insert, wherein operative
cooperation between the pair of rollers and the first, second, and
third inserts delays movement of the bolt and bolt carrier
subsequent to firing of the shotgun without locking movement of the
bolt or the bolt carrier.
2. The roller delayed blowback action system of claim 1, wherein
each insert includes a surface.
3. The roller delayed blowback action system of claim 1, wherein
each insert is removably attached.
4. The roller delayed blowback action system of claim 1, wherein
each insert includes hardened steel.
5. The roller delayed blowback action system of claim 1, wherein
the pair of rollers are slideably moveable within a plane
substantially perpendicular to the longitudinal axis.
6. The roller delayed blowback action system of claim 2, wherein
each of the surfaces includes an arcuate geometry such that a
plurality of contact angles between the first or second roller and
the surface of its respective proximate inserts cooperate to
provide a variable resistance to rearward movement of the bolt or
bolt carrier.
7. (canceled)
8. A roller delayed blowback action system for a semi-automatic
shotgun having a receiver including an ejection port for expelling
an empty cartridge of a fired projectile, the roller delayed
blowback action system comprising: a bolt operatively attached to a
bolt carrier, the bolt and the bolt carrier being movable within
the receiver and substantially parallel to a longitudinal axis; a
roller-delay assembly comprising: a pair of surfaces--a first
surface and a second surface--extending from within the receiver; a
third surface extending from the bolt carrier; and, a pair of
rollers--a first roller and a second roller--positioned rearward of
the ejection port and substantially contained within the bolt, the
first roller proximate the first and the third surfaces, and the
second roller proximate the second and third surfaces, wherein
operative cooperation between the pair of rollers and the first,
second, and third surfaces delays movement of the bolt and bolt
carrier subsequent to firing of the shotgun without locking
movement of the bolt or the bolt carrier.
9. The action system of claim 8, wherein each of the surfaces
includes an arcuate geometry.
10. The action system of claim 9, wherein the arcuate geometry is a
curve facilitating a variable resistance to rearward movement of
the bolt carrier and/or bolt.
11. The action system of claim 9, wherein the arcuate geometry is a
curve facilitating a decreasing resistance to rearward movement of
the bolt carrier and/or bolt.
12. (canceled)
13. The action system of claim 8, wherein the first surface is
integral to a first insert operatively attached to the receiver and
the second surface is integral to a second insert operatively
attached to the receiver.
14. The action system of claim 13, wherein the first and second
inserts are removably attached within the receiver.
15. The action system of claim 8, wherein the third surface is
integral to a third insert operatively attached to the bolt
carrier.
16. The action system of claim 15, wherein the third insert is
removably attached to the bolt carrier.
17-23. (canceled)
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part that claims the
benefit of U.S. patent application Ser. No. 11/003,073, filed Dec.
3, 2004; which claims the benefit of U.S. Provisional Patent App.
No. 60/526,540, filed Dec. 3, 2003; the contents of which are
expressly incorporated herein by reference.
TECHNICAL FIELD
[0002] The invention relates generally to the field of firearms,
and more specifically to the operating system of a firearm.
BACKGROUND OF THE INVENTION
[0003] The roller-lock delayed blowback action system has been
employed in rifles and sub-machine guns since the 1950's and is
well known to those familiar with firearm design, but it has not
previously been employed in a semi-automatic shotgun. This is
likely because the large diameter of the cartridge would require a
disproportionately bulky mechanism and would interfere with the
space necessary for feeding and ejecting the cartridges when
situated near the front of the bolt--as in all previous known
designs. However, it is desirable to provide a roller-lock delayed
blowback action system for a shotgun because it would offer an
alternative to: gas-operated systems that are subject to fouling;
recoil-operated systems that are notoriously unreliable; and
straight blowback systems that require an undesirable heavy
bolt.
[0004] Additionally, a firearm incorporating known delayed-blowback
roller-lock action system generally uses the same size or type of
ammunition. As such, utilizing a constant resistance to impede
rearward movement of the bolt and/or bolt carrier works well. In
contrast, employing a constant or fixed amount of rearward
resistance for use in a shotgun that is capable of firing a wide
range of ammunition sizes and types e.g., 23/4 inch light target
loads, 3 inch magnum slug loads, non-lethal projectiles--does not
work as well. Thus, to accommodate the wide range of ammunition
utilized in a semi-automatic shotgun, there is a need for a delayed
roller-lock action system capable of providing a variable amount of
resistance to rearward movement of the bolt and/or bolt
carrier.
[0005] The present invention is provided to address these and other
considerations.
SUMMARY OF THE INVENTION
[0006] The present invention is a roller-lock delayed blowback
mechanism providing a compact, low-maintenance, reliable, and
lightweight action system for a firearm, preferably a
semi-automatic shotgun. A primary roller-lock mechanism is located
to the rear of the feeding and ejecting ports of the firearm and
preferably contained within the approximate diameter of a
cartridge.
[0007] An alternative embodiment of the present invention further
incorporates a secondary, or compounding, roller-lock mechanism
within the action system to further delay the opening of the
firearm chamber. This is advantageous because locating the locking
rollers to the rear of the ejection port obviates the use of a
relatively long and proportionately heavy bolt in which the rollers
are caged. Thus, a relatively lighter bolt carrier--to be
accelerated past inwardly pinching rollers--provides less inertial
resistance to the accelerating force than prior conventional
designs wherein the bolt carrier is proportionately larger,
heavier, and more resistant to acceleration. That is, the reduced
delaying effect of the primary roller-lock mechanism brought about
by the necessarily diminished physical space requirements, has been
increased by compounding the primary roller-lock mechanism rather
than by adding mass. In the preferred embodiment, the inertia of a
relatively lesser mass (the firing pin and striking hammer)
sufficiently delays the opening of the firing chamber until the
explosive pressure within is reduced to a safe level by retarding
the movement of the bolt carrier relative to the bolt, which in
turn retards the movement of the bolt relative to the barrel and
receiver of the shotgun. The compounding or additional stage of
roller-lock delay is increased similar in effect to compounding a
1:10 gear ratio to produce a 1:100 ratio.
[0008] A further aspect of the present invention is directed to an
action system for a semi-automatic shotgun having a receiver
including an ejection port for expelling an empty cartridge of a
fired projectile. The action system includes a bolt attached to a
bolt carrier, wherein the bolt and the bolt carrier are movable
within the receiver and substantially parallel to a longitudinal
axis. A surface is attached to the bolt carrier or the receiver,
and, a roller is positioned rearward of the ejection port and
proximate the surface.
[0009] Another further aspect of the present invention includes the
surface having an arcuate geometry to provide a variable resistance
to rearward movement of at least the bolt or bolt carrier. The
surface can be at least a portion of an insert comprised of
hardened steel and be removably attached to firearm's receiver,
bolt, or bolt carrier.
[0010] Yet another further aspect of the present invention includes
an action system for a semi-automatic shotgun having a receiver
including an ejection port for expelling an empty cartridge of a
fired projectile. The action system includes a bolt attached to a
bolt carrier, wherein the bolt and the bolt carrier are movable
within the receiver and substantially parallel to a longitudinal
axis. The action system further includes a roller-lock assembly
comprising a roller positioned rearward of the ejection port, and a
pair of surfaces--an inner surface and an outer surface--positioned
proximate the roller, wherein the roller and the pair of surfaces
cooperate to provide a resistance to rearward movement of at least
the bolt or bolt carrier. The action system may further include
another roller-lock assembly, wherein the pair of roller-lock
assemblies is symmetrically positioned about a longitudinal plane
including the longitudinal axis.
[0011] A still further aspect of the present invention is directed
to a method for delaying movement of a bolt in response to firing
of the semi-automatic shotgun. The method includes: positioning a
roller rearward of the ejection port; providing a resistance to
rearward movement of the bolt in response to the firing of the
semi-automatic shotgun; and, varying the resistance.
[0012] These and other aspects and attributes of the present
invention will be discussed with reference to the following
drawings and accompanying specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of a semi-automatic
shotgun;
[0014] FIG. 2 is a partial horizontal cross-sectional view of the
action system of the present invention;
[0015] FIG. 3 is a partial vertical cross-sectional view of the
action system of the present invention;
[0016] FIG. 4 is a partial perspective view of the action system of
the present invention in battery position;
[0017] FIG. 5 is a partial perspective view of the action system of
the present invention in open position;
[0018] FIG. 6 is a partial perspective horizontal cross-sectional
view of the action system of the present invention in battery
position;
[0019] FIG. 7 is a partial perspective vertical cross-sectional
view of the action system of the present invention in battery
position; and,
[0020] FIG. 8 is a perspective view of one embodiment of the
present invention; and,
[0021] FIG. 9 is a partial perspective cross-section view of an
alternate embodiment of the present invention;
[0022] FIG. 10 is a partial perspective view of the alternate
embodiment shown in FIG. 9;
[0023] FIG. 11 is a partial cross-section plan view of one aspect
of the present invention wherein the firearm is shown in battery
position;
[0024] FIG. 12 is a partial cross-section plan view of one aspect
of the present invention wherein the firearm is shown in rearward
transition;
[0025] FIG. 13 is a partial cross-section plan view of one aspect
of the present invention wherein the firearm is shown near the
terminus of its rearward transition; and,
[0026] FIGS. 14A-14C are partial cross-section plan views depicting
the roller-lock assembly's various angles of contact during various
positions of the action system.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0027] While the present invention is susceptible of embodiment in
many different forms, there is shown in the drawings and will
herein be described in detail preferred embodiments of the
invention with the understanding that the present disclosure is to
be considered as an exemplification of the principles of the
invention and is not intended to limit the broad aspect of the
invention to the embodiments illustrated.
[0028] FIG. 1 depicts a semi-automatic shotgun having a roller-lock
mechanism deployed within a reinforcing boss 4 on a receiver 2. A
bolt 1 rides within the receiver 2 to close a firing chamber 20 in
a barrel 5. The bolt 1 extends rearward past an ejection port 3
when out of battery position. It should be noted that in this and
other figures, certain details of the firearm not related to the
patentable aspects of the present invention--such as the trigger
mechanism and magazine--are not enumerated.
[0029] FIGS. 2 and 6 depict a partial horizontal cross-sectional
view about the centerline of the firearm barrel 5 showing the
primary roller-lock mechanism of one embodiment of the present
invention. The primary roller-lock mechanism is positioned rearward
of the ejection port 3 and preferably comprises the bolt 1, a bolt
carrier 6, primary bearing(s) 7 (e.g., roller(s)), and a barrel
extension 13. When the cartridge 19 is fired by a hammer 9
impinging on a firing pin 8, the explosive gas pressure in the
firing chamber 20 forces the bolt 1--which cages the rollers
7--rearward; thus pinching the rollers between detents 12, e.g.,
angled ramps, in the fixed barrel extension 13 and detents 11,
e.g., angled ramps, in the moveable bolt carrier 6. This results in
the bolt carrier 6 being rapidly accelerated rearward past the
inwardly pinching rollers 7 until the rollers 7 clear the fixed
ramps 12 in the barrel extension 13 wherein the bolt 1 is free to
travel rearward to eject the spent cartridge 19 through the
ejection port 3 and compress the return spring 10.
[0030] At the terminus of its rearward travel within the receiver
2, the bolt 1 is impelled forward by the return spring 10 to pick
up a new cartridge 19 and load it into the firing chamber 20. When
the bolt 1 reaches its forward terminus (in battery), the return
spring 10 and inertia continue to drive the bolt carrier 6 forward
until its inclined ramps 11 have forced the rollers 7 outward
against the inclined ramps 12 of the barrel extension 13, thus
wedging the bolt 1 firmly in battery against the barrel 5. This
primary roller-lock delay mechanism serves to delay the opening of
the firing chamber 20 until the gas pressure is reduced to a
predetermined, e.g., safe, level.
[0031] Because the delay effect of the primary roller-lock
mechanism is chiefly dependant on the inertial resistance of the
mass of the bolt carrier (6) and it is undesirable to increase that
mass to augment the delay, an alternative embodiment of the present
invention incorporates a secondary roller-lock mechanism within the
bolt itself.
[0032] FIGS. 3 and 7 depict a partial vertical cross-sectional view
of the secondary, or compounding, roller-lock mechanism comprising
a secondary bearing 16, e.g., roller(s), caged within the bolt
carrier 6 between detents 14, e.g., inclined ramps, in the bolt 1
and detents 15, e.g., inclined ramps, in the firing pin 8. When a
striking hammer 9 is released by the trigger mechanism (not shown),
it drives the firing pin 8 forward to ignite the cartridge 19. At
the forward terminus of its 8 travel, angled ramps 15 in the firing
pin 8 force the secondary rollers 16 caged in the bolt carrier 6
outward against the angled ramps 14 in the bolt 1--effectively
wedging the bolt carrier 6 into the bolt 1. When the cartridge 19
is fired, the resulting gas pressure in the firing chamber 20
applies rearward force to the bolt 1. The bolt's movement is
delayed by the primary roller-lock mechanism of FIG. 2 described
above, and the bolt carrier 6 therein described is delayed from
moving relative to the bolt 1 until the secondary rollers 16 caged
within the bolt carrier 6 are pinched inward by the inclined ramps
14 in the bolt 1 against the inclined ramps 15 in the firing pin
8--thus accelerating the firing pin 8 rearward against the striking
hammer 9. The result of this compounding mechanism is the
relatively small inertial mass of the firing pin 8 and striking
hammer 9 can effectively and securely delay the opening of the bolt
1 until the gas pressure in the firing chamber 20 has dropped to a
safe level.
[0033] FIG. 4 depicts a partial perspective view of the action
system of the present invention in battery position, specifically
showing the primary rollers 7 wedged outward by the ramps 11 in the
bolt carrier 6 into receiving pocket(s) 22 in the barrel extension
13, and the position of the primary roller-lock mechanism relative
to the ejection port 3.
[0034] FIG. 5 depicts a partial perspective view of the action
system of the present invention out of battery position,
specifically showing the rollers 7 in the cage 17 in the bolt 1,
pinched inward against the ramps in the bolt carrier 6, which is
extended rearward relative to the bolt 1.
[0035] FIG. 8 depicts the relative positions of the primary 7 and
secondary 16 rollers to the firing pin 8, which is coaxial with the
barrel 5, bolt 1, and bolt carrier 6. It is noted here that the
primary and secondary rollers need not necessarily be located in
perpendicular planes, or symmetrically opposed about the common
centerline, or in a particular forward/rearward orientation, but
are so oriented in the preferred embodiment for simplicity and ease
of manufacture.
[0036] It is to be understood that the present invention preferably
utilizes a pair of rollers for the primary roller-lock mechanism,
but that a single bearing, e.g., roller, can be utilized to
effectively delay the opening of the firing chamber until the
explosive pressure within is reduced to a safe level. Similarly, a
single bearing or roller can be utilized for the secondary
roller-lock mechanism.
[0037] It is further to be noted that although the present
invention is preferably devised to enable a roller-lock delayed
blowback action system for a semi-automatic shotgun, the present
invention can easily be employed by one of ordinary skill in the
art to firearms other than semi-automatic shotguns.
[0038] The linear surface(s) 11, 12 provides a constant, limited
range of applied resistant-force to rearward movement of the bolt 1
and/or bolt carrier 6. In other words, if the straight surfaces 11,
12 were angled so as to provide a low amount of resistance--and
therefore allow very low-powered ammunition to cycle the firearm's
action--a similar amount of resistance would correspondingly be
provided to very high-powered ammunition, and thus be insufficient
to prevent bulging or fracturing of the firearm. Likewise, if the
straight surface(s) 11, 12 were angled so as to initially provide a
high amount of resistance--and therefore provide sufficient
rearward resistance to the bolt 1 and/or bolt carrier 6 in response
to high-powered ammunition--a similar amount of rearward resistance
to the bolt 1 and/or bolt carrier 6 would correspondingly be
provided in response to low-powered ammunition, and thus
unsatisfactorily prolong the delay to cycle the firearm's action,
or prevent it altogether.
[0039] In reference to the delayed roller-lock system incorporating
a linear ramp or surface 11, 12 described above and depicted in
FIGS. 1-8, certain modifications are now described that relate
directly to the functional aspects of the ramp(s)/surface(s).
Namely, the ramp(s)/surface(s) includes an arcuate geometry, e.g.,
a curvature including a constant or variable radius, that is
capable of providing a varied amount of resistance to rearward
movement of the bolt 1 and/or bolt carrier 6.
[0040] FIGS. 9-13 depict an action system for a semi-automatic
shotgun including a receiver 2 having an ejection port 3 for
expelling an empty cartridge 19 of a fired projectile. As shown in
FIGS. 9 and 10, the action system includes a bolt 1 operatively
attached to a bolt carrier 6. Both the bolt 1 and the bolt carrier
6 are movable within the receiver 2 and substantially parallel to a
longitudinal axis 30 infinitely extending from the firearm's barrel
5. The action system further includes a means for providing an
amount of resistance to rearward movement of the bolt 1 and bolt
carrier 6. The resistance to the rearward movement of the bolt 1 is
provided by a roller-lock assembly 32 including a roller 7
positioned rearward of the ejection port 2 and a pair of
surfaces--inner 34 and outer 36--are positioned proximate the
roller. In addition, another roller-lock assembly 32' can be
symmetrically positioned about the opposing side of the
longitudinal axis 30.
[0041] Although the inner surface 34 may be a portion of the bolt
carrier 6 and the outer surface 36 may be a portion of the receiver
2, it is preferable however that at least one of the inner or outer
surfaces is at least a portion of an insert 38, 38'. The inserts
38, 38' may include hardened steel and be removably attached to the
receiver 2 or bolt carrier 6. Additionally, it is possible for one
insert 38, 38' to contain more than one inner surface 34, or outer
surface 36.
[0042] FIGS. 11-13 depict movement of the rollers 7--substantially
contained within the bolt 1 and within a plane perpendicular to the
longitudinal axis 30--with respect to the surfaces 34, 36 wherein
resistance to rearward movement of the bolt 1 and/or bolt carrier 6
is provided. Initially, rearward movement of the bolt 1 pushes the
rollers 7 rearward, i.e., downward with respect to FIG. 11. Upon
continued rearward urging by the bolt 1, the rollers 7 impinge upon
the inner 34 and outer 36 surfaces of the inserts 38, 38' and
eventually slide towards the longitudinal axis 30 (see FIG. 12),
further applying pressure to the inner surfaces 34 to urge the bolt
carrier 6 rearward (see FIG. 13).
[0043] As seen in FIGS. 11-13, inner 34 and outer 36 surfaces
include a portion having an arcuate surface for cooperative
engagement with the rollers 7. The arcuate surfaces provide an
amount of resistance to rearward movement of the bolt 1 and bolt
carrier 6. The arcuate surfaces shown in FIGS. 9-13 include a curve
having a constant or variable radius. Because the angle of contact
.alpha., .beta. between the rollers 7 and the surfaces 34, 36
changes throughout rearward movement of the rollers, the radius of
curvature of the surfaces can be designed in consideration of the
amount of resistance desired to be applied to the rearwardly moving
bolt 1 and bolt carrier 6.
[0044] Referring now to FIGS. 14A-14C, the angle of contact a
involving the roller 7 and the inner surface 34 is defined between
the longitudinal axis 30 and a line L.sub.1 tangent to the roller
and including the point of contact of the roller and the inner
surface. The angle of contact .beta. involving the roller 7 and the
outer surface 36 is defined between a line L.sub.O tangent to the
roller and including the point of contact of the roller and the
outer surface, and a line L.sub..perp. extending perpendicular to
the longitudinal axis 30 at the intersection of the longitudinal
axis and the tangent line L.sub.O.
[0045] The arcuate geometry of the inner 34 and outer 36 surfaces
is capable of providing a variable amount of resistance to the
rearward movement of at least the bolt 1 or bolt carrier 6. That
is, the curved inner 34 and outer 36 surfaces can initially provide
a higher amount of resistance to the rearward movement of the bolt
1 that subsequently decreases, and vice versa. Depending on the
desired amount and application of resistance, the radius of
curvature of the arcuate surface 34, 36 can be designed
accordingly, e.g., the radius can be fixed or variable--radii.
[0046] In contrast to the linearly straight ramp 11, 12 utilized in
FIGS. 1-8, the arcuate, radiused surfaces 34, 36 include a convex
geometry capable of having a continually changing contact angle and
providing a variable amount of resistance to the rearward movement
of at least the bolt 1 or bolt carrier 6. That is, the radiused
surfaces 34, 36 initially provide a higher amount of resistance to
the rearward movement of at least the bolt 1 or bolt carrier 6 that
subsequently decreases.
[0047] Initially providing a greater amount of resistance to the
rearward movement of at least the bolt 1 or bolt carrier 6 is
beneficial when firing extremely high-powered shotgun ammunition.
Similarly, subsequently decreasing the resistance to the rearward
movement of at least the bolt 1 or bolt carrier 6 provides the
firearm's action system with the ability to cycle low-powered
shotgun ammunition.
[0048] In FIGS. 9-13, symmetrically opposed hardened steel inserts
38' are fixed in the receiver 2 of the firearm along the path of
the bolt 1--substantially parallel with the longitudinal axis
30--which substantially cages the rollers 7 and slides over the
bolt carrier 6 in which is fixed a hardened steel insert 34 upon
which the rollers impinge. When the bolt 1 is in battery--depicted
in FIG. 11--the radiused inner surfaces 34 of the insert 38 in the
bolt carrier 6 impinge outwardly on the rollers 7, which in turn
impinge on the radiused outer surfaces 36 of the inserts 38' fixed
in the receiver 2 and on the flat surfaces 17 of the bolt 1, which
holds the shotgun shell in the chamber of the firearm. When the
shell is fired, the bolt 1 is forced rearward, applying force from
the flat surface 17 to the roller 7, which applies force to the
outer surfaces 36 of the insert 38' attached to the receiver 2 and
the inner surfaces 34 of the insert 38 attached to the bolt carrier
6 until the bolt carrier is accelerated rearward as depicted in
FIGS. 12 and 13, in which the rearward motion of the bolt 1 is no
longer resisted or delayed and the bolt opens to eject the fired
shell and cycle the action.
[0049] As depicted in FIG. 11, the initial resistance to the
applied force is dependant on the contact angles .alpha., .beta. at
the points of contact between the rollers 7 and the radiused
surfaces 34, 36 of the inserts 38, 38'. The resistance is inversely
proportional to the angles of contact .alpha., .beta.. That is, as
the angles of contact .alpha., .beta. decrease, the resistance
increases; and as the bolt carrier 6 begins to move, the angles of
contact .alpha., .beta. increase and the resistance decreases.
Thus, the arcuate surfaces 34, 36--in combination with the rollers
7--provide the firearm with the ability to safely and reliably
cycle the action system in response to both very high powered and
very low powered ammunition, i.e., providing a sufficient initial
resistance that decreases rapidly. As such, the present invention
provides firearms, e.g., shotguns, utilizing a delayed roller-lock
action system with the ability to operate safely and reliably over
a wide range of ammunition.
[0050] It is also to be understood that the present invention may
be embodied in other specific forms without departing from the
spirit or central characteristics thereof. The present embodiments,
therefore, are to be considered in all respects as illustrative and
not restrictive, and the present invention is not to be limited to
the details provided herein. While specific embodiments have been
illustrated and described, numerous modification come to mind
without significantly departing form the characteristics of the
present invention and the scope of protection is only limited by
the scope of the accompanying claims.
* * * * *