Hybrid airgun

A hybrid airgun includes a compressed gas chamber; a barrel; a firing valve between chamber and barrel; a secondary cylinder divided into front and back volumes by a secondary piston, the front volume connected to the chamber; a liquefied gas chamber connected to the back volume; a valve for transferring liquefied gas into the liquefied gas chamber; a cocking mechanism; and a firing mechanism. The cocking mechanism fills the compressed gas chamber with a compressed first gas, and/or transfers a liquefied second gas into the liquefied gas chamber. The firing mechanism opens the firing valve. During flow of the first gas into the barrel, pressure exerted by the second gas in the back volume moves the secondary piston and partially disengages it from the secondary cylinder, thereby enabling the second gas to flow into the compressed gas chamber, through the firing valve, and into the barrel.

BACKGROUND

The field of the present invention relates to airguns. A hybrid airgun employing compressed gas and/or liquid gas propellants is disclosed herein.

Airguns for hunting or target shooting operate by a variety of mechanisms, each with its respective advantages and shortcomings. Single-stroke pneumatic airguns are convenient to operate, and exhibit consistent performance, but provide limited muzzle energies. Multi-stroke pneumatic airguns may provide greater muzzle energies, but are difficult and/or tiring to operate, and are less consistent in their performance. Pre-charged pneumatic airguns may provide higher muzzle energies and low recoil, but require access to compressed air tanks and associated support facilities. Carbon dioxide airguns may be conveniently supplied with bottled liquid carbon dioxide, but have relatively low muzzle energies which vary significantly with ambient temperature. Spring piston airguns provide higher muzzle energies, but are difficult to cock, and suffer from large recoil.

SUMMARY

A hybrid airgun comprises: a compressed gas chamber; a barrel; a firing valve controlling gas flow between the compressed gas chamber and the barrel; a secondary cylinder divided into front and back volumes by a secondary piston, the front volume being connected to the compressed gas chamber; a liquefied gas chamber connected to the back volume; a valve for transferring a volume of liquefied gas into the liquefied gas chamber; a cocking mechanism; and a firing mechanism. The cocking mechanism i) fills the compressed gas chamber with a first gas at an elevated pressure, and/or ii) transfers a volume of a liquefied second gas into the liquefied gas chamber through the transfer valve. The firing mechanism opens the firing valve. Compressing a first gas in the compressed gas chamber to an elevated pressure moves the secondary piston so as to reduce the back volume. Pressure exerted by a liquefied second gas transferred into the liquefied gas chamber moves the secondary piston so as to reduce the front volume and further compress the first gas to about the saturation pressure of the second gas. Upon firing of the airgun, the first gas flows through the firing valve into the barrel, and pressure exerted by the second gas in the back volume moves the secondary piston so as to reduce the front volume and maintain pressure of the first gas near the saturation pressure of the second gas during at least an initial portion of the flow of the first gas into the barrel (and movement of the projectile down the barrel). During an intermediate portion of the flow of the first gas into the barrel, pressure exerted by the second gas in the back volume moves the secondary piston so as to at least partially disengage the secondary piston from the secondary cylinder, thereby enabling the second gas to flow into the compressed gas chamber, through the firing valve, and into the barrel.

Objects and advantages pertaining to airguns may become apparent upon referring to the disclosed embodiments as illustrated in the drawings and disclosed in the following written description and/or claims.

The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present disclosure and/or appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS

FIGS. 1 through 5illustrate construction and operation of an exemplary embodiment of a hybrid airgun. A compressed gas chamber, also referred to as a firing chamber, is formed by a primary cylinder8A and a primary piston8that moves within cylinder8A. Piston8is mechanically linked to a first lever1by rod6via pins1B and6A. The first lever1is pivotably connected to the airgun at pin1A. Lever1, rod6, and the airgun together form a so-called four-bar mechanism, and form a portion of a cocking mechanism for the exemplary airgun ofFIGS. 1–5(“cocking” generically designating those functions required for preparing the gun to be fired). Pivoting of lever1about pin1A yields reciprocating movement of primary piston8within primary cylinder8A. As lever1swings downward and away from the airgun during cocking of the airgun, piston8moves so that the volume of the compressed gas chamber increases. At the end of this motion, piston8and/or cylinder8A may be suitably adapted for admitting ambient air to serve as a compressed gas, which is compressed within the compressed gas chamber upon completion of cocking the airgun and prior to firing. Suitable adaptations may include groove(s), chamfer(s), or other structural alteration(s) of the cylinder and/or piston so as to enable partial disengagement of the piston from the cylinder near the end of its outward motion, allowing air to enter the compressed gas chamber.

A secondary cylinder is connected to the compressed gas chamber, and is divided into a front volume9A and a back volume9B by a secondary piston9(also referred to as an equalization piston). It should be noted that the terms “front” and “back” are functional in nature, and need not be related to the front and back ends of the airgun. The front volume9A is connected to the compressed gas chamber, while the back volume is connected to a passage22. When fully engaged with the secondary cylinder, the secondary piston9substantially prevents gas flow between the front volume9A and the back volume9B. Secondary piston9and/or the secondary cylinder within which it moves may be adapted so that as the secondary piston9moves to reduce the front volume9A, at some point the secondary piston9becomes at least partially disengaged from the secondary cylinder, allowing gas flow between the front volume9A and the back volume9B. A return spring prevents secondary piston9from completely leaving the secondary cylinder, and in the absence of sufficient pressure in the back volume fully re-engages the secondary piston9within the secondary cylinder. Suitable adaptation(s) of the secondary cylinder and/or secondary piston9may include groove(s), chamfer(s), and/or other suitable structural alteration(s) that enable partial disengagement of the piston and cylinder.

In the exemplary embodiment of the hybrid airgun, lever1is provided with a sliding handle2, shown including slider pins3sliding within slots in lever1. The sliding handle2includes a tongue24for engaging safety latch4, serving as a safety mechanism to ensure that various cocking actions occur in the proper sequence. Lever1cannot be pivoted away from the airgun to cock it until handle2slides backwards to disengage the tongue24from safety latch4. Sliding of handle2actuates several components of the cocking mechanism necessary for cocking the gun by pushing back on rod5(via a groove25received within a slot on the sliding handle2), which is mechanically linked to a second lever15(also referred to as a pivot plate, which pivots about pin15A). Pivot plate15is mechanically linked to cocking bar14at pin14A, so that when handle2is pulled back to begin cocking the gun, cocking bar14is pulled back by pivoting of pivot plate15. This backward motion of the cocking bar14pulls a striker11back against a spring13until striker11is retained against the force of spring13by trigger7. Backward movement of the striker11allows a return spring to close firing valve10, isolating the compressed air chamber from the barrel20. An alternative mechanism for pulling striker11back may include a pin or other mechanical link between bolt12and striker11, so that pulling back the bolt12to load the gun also acts to pull back striker11and allow firing valve10to close (in this instance bolt12functions as a portion of the cocking mechanism, and cocking bar14may act as a stop to prevent cocking of the airgun prior to pulling back bolt12). Another alternative mechanism may include a return spring for automatically closed firing valve10after firing the airgun. Such a return spring would therefore form a portion of the cocking mechanism (which would require no action on the part of a user).

Pivot plate15is also mechanically linked to rod18at pin18A. Rod18reciprocates within a passage44within the stock of the gun, and is adapted at its lower end to act as a shuttle valve19for transferring liquefied gas through passage22to the second volume9B of the secondary cylinder. The shuttle valve19comprises a pair of enlarged chambers46and50of passage44, four O-ring seals (45/47/49/51) variously engaged between rod18and passage44, and a reduced-diameter segment48of rod18between the second and third O-ring seals47and49. Enlarged chamber50is connected to back volume9B through passage22, while enlarged chamber46is connected to a liquefied gas reservoir16through passage43. As handle2slides backwards and rod5causes pivoting of pivot plate15, rod18is pushed downward through passage44into a filling position, illustrated inFIG. 4. Enlarged chamber46is sealed at each end by O-rings45and49engaged with passage44, and a liquefied second gas (liquid carbon dioxide in this example) flows out of reservoir16, through passage43and into chamber46. In this position enlarged chamber50, passage22, and back volume9B are open to the atmosphere through the upper end of passage44. When rod5is drawn forward again (later in the cocking sequence; described further hereinbelow), a volume of liquefied gas is trapped between O-rings47and49when O-ring47leaves enlarged chamber46and engages passage44. The volume of liquefied gas transferred is defined by passage44, O-rings47and49, and the reduced diameter segment48of rod44. As rod44is drawn further forward, O-ring51leaves enlarged chamber50engages passage44, while O-ring49enters enlarged chamber50, disengaging from passage44. In this position (referred to as the charging position; illustrated inFIG. 5), liquefied gas and/or its vapor may flow through passage22into back volume9B. Engaged O-ring51isolates the enlarged chamber50(also referred to as a liquefied gas chamber) from the atmosphere, while engaged O-ring47isolates the liquefied gas chamber from the liquefied gas reservoir16.

Once the handle2is pulled back and tongue24is disengaged from safety latch4, firing valve10is closed and liquefied gas fills chamber46through the action of rod5and pivot plate15. At this point a first gas (ambient air in this example) may be drawn into the compressed gas chamber and then compressed to an elevated pressure. Air is drawn into the cylinder8A (through the secondary cylinder around the partially disengaged secondary piston9) as the lever1is pivoted downward and away from the airgun. If the primary cylinder and primary piston are suitably adapted (as described hereinabove), air may enter the compressed gas chamber when the primary piston8partially disengages from the primary cylinder8A. The air (or other first gas) is then compressed to an elevated pressure within the compressed gas chamber as the lever1swings back up toward the airgun and the primary piston moves within the primary cylinder to reduce the volume of the compressed gas chamber. The compressed gas is substantially confined within the compressed gas chamber by the closed firing valve10, and by re-engagement of the secondary piston9within the secondary cylinder (as described hereinabove). As the first gas is compressed within the compressed gas chamber, the elevated pressure causes the secondary piston9to move within the secondary cylinder to maximize the front volume9A. Residual air and/or gas(es) in the back volume9B are vented through passage22, chamber50, and the upper portion of passage44(as inFIG. 4). As the lever1pivots back up toward the airgun, the four-bar mechanism undergoes an inversion that forces the lever1into its starting position.

Once the lever1is pulled back up to the airgun, thereby maximally compressing the first gas in the compressed air chamber, the slot in the handle2re-engages the groove25of rod5. The sliding handle2slides forward, re-engaging tongue24and safety latch4, and pulling rod5forward to its original position. Re-engagement of tongue24and safety latch4ensures that the four-bar mechanism cannot accidentally release from the inversion and violently spring apart (the so-called “bear trap effect”). This safety mechanism is even more important later when the liquefied gas chamber50is filled with the second gas, further increasing the pressure within the compressed gas chamber. Forward movement of rod5in turn causes forward movement of pivot plate15, pulling the cocking bar14forward and pulling rod18up through passage44. Forward movement of cocking bar14removes it as an obstacle to forward motion of the striker11when released by the trigger7, so that the airgun is ready for firing.

Movement of rod18up through passage44to the charging position (FIG. 5) transfers a volume of liquefied second gas into the chamber50, through passage22, and into back volume9B of the secondary cylinder (as described hereinabove). A portion of the liquefied second gas changes to vapor at the saturation pressure, which typically exceeds the elevated pressure of the compressed gas chamber. As a result, pressure exerted by the second gas in the back volume9B moves the secondary piston9so as to reduce the front volume9A and further compress the first gas to about the saturation pressure of the second gas. The range of movement of the secondary piston9, the amount of the liquefied second gas converted to vapor, and the final pressure achieved in the compressed gas chamber depend on the identity of the second gas and the operating temperature of the airgun (discussed further hereinbelow).

At this point the airgun is fully charged and ready for loading and firing. A pellet is inserted into the breach at the rear of the barrel20, and bolt12is closed and locked into place. A push rod at the end of bolt12pushes the pellet past passage21, which connects the barrel20and the compressed gas chamber. To fire the airgun, trigger7is pulled, releasing striker11to move forward under the impetus of spring13. Striker11hits the stem of firing valve10, breaking its seal and pushing it forward against its return spring. Spring13holds the firing valve10open against the force exerted by the weaker return spring. The compressed first gas in the compressed gas chamber is now free to flow through the firing valve and passage21and into barrel20. The flow of compressed first gas into the barrel accelerates the pellet forward through the barrel. During an initial portion of the flow of the first gas into the barrel20from the compressed gas chamber, pressure exerted by the second gas in the back volume9B moves the secondary piston9so as to reduce the front volume9A and maintain pressure of the first gas near the saturation pressure of the second gas during an initial portion of the flow of the first gas into the barrel20. How close to the second gas saturation pressure the compressed gas chamber remains depends on a variety of variables, such as the mass of and friction on the secondary piston9and the stiffness of its return spring, and the flow resistances of the passages21and22.

At an intermediate point in the flow of the first gas through the firing valve10into the barrel20, the secondary piston9moves to reduce the front volume9A and reaches a position where it becomes partially disengaged from the secondary cylinder. Any remaining liquefied second gas promptly vaporizes, and the second gas flows past piston9from the back volume9B into the front volume9A, into the compressed gas chamber, through passage21and the firing valve10, and into barrel20, mixing with the first gas. The flow of the second gas into the barrel20increases the acceleration of the pellet over the acceleration that would be obtained from expansion of the first gas alone.

After firing, when the flows of first and second gases have ceased and all pressures have returned to near atmospheric pressure, the return spring re-engages secondary piston9within the secondary cylinder, separating the front volume9A from the back volume9B. Elevated pressure within the compressed gas chamber from the next cocking sequence forces the secondary piston through the secondary cylinder to minimize the back volume9B, with residual gases vented through passage22, chamber50, and passage44(as described earlier). The firing valve10will not close until the cocking bar14pulls back the striker13when the handle2is pulled back for the next cocking sequence. In this way, the cocking mechanism ensures unless firing valve10is closed, the first gas cannot be compressed within the compressed gas chamber, and the liquefied second gas is not charged into chamber50or back volume9B.

For optimal operation of the airgun, the secondary piston9must respond quickly to any pressure differential between front volume9A and back volume9B. The entire flow of the first and second gases through the firing valve typically occurs in about 5 msec or less. The mass of secondary piston9should be as small as practicable, while resistance to movement or tendency to bind within the secondary cylinder should be as small as practicable. Lengthening the secondary piston reduces its tendency to bind, while the mass may be reduced by hollowing out the back end of the piston and using a suitable lightweight material (aluminum for example; other material may be employed). The overall volume of the back volume9B should be as small as practicable, to reduce the volume of liquefied gas consumed per shot. If the backside of secondary piston9is hollowed out to reduce its mass, the secondary cylinder may be provided with a corresponding protrusion which “fills in” the hollowed out backside of the piston when the back volume9B is at its minimum. Many sizes, masses, materials, and/or configurations for piston9may be employed while remaining within the scope of the present disclosure and/or appended claims. A suitable adaptation for enabling partial disengagement of the secondary piston9from the secondary cylinder may comprise a slightly widened end portion of front volume9A, and one or more longitudinal groove(s) along secondary piston9behind an O-ring seal. Piston9becomes partly disengaged from the secondary cylinder when the O-ring seal reaches the widened portion of the front volume9A, and the second gas flows along the longitudinal groove(s) and past the O-ring seal and into the front volume. After gas flow has ended, the return spring re-engages the O-ring seal with the narrower portion of the secondary cylinder. Many other adaptations of piston9and/or the secondary cylinder may be employed for providing partial disengagement and flow of gas from the back volume to the front volume while remaining within the scope of the present disclosure and/or appended claims.

The particular mechanical arrangements shown for the four bar mechanism, the trigger7, sliding handle2, rod5, pivot plate15, the cocking bar14, striker13, firing valve10, shuttle valve19, liquefied gas reservoir16, and so forth are exemplary, and should not be construed as limiting the scope of the present disclosure or the appended claims. It is well known that there exist myriad equivalents, variants, and/or alternatives to these particular structures and mechanisms, and any suitable combination of such equivalents, variants, and/or alternatives shall fall within the scope of the present disclosure and/or appended claims. In particular, a phrase such as “cocking mechanism”, “safety mechanism”, or “firing mechanism” may not always indicate a single component or a group of coupled components, but shall also encompass a group of independently actuated components for achieving the necessary functions for cocking and/or firing the airgun.

The primary piston8and cylinder8A, along with the four-bar mechanism, may be arranged to yield compression of ambient air to between about 400 psig and about 600 psig with a single stroke, typically around 500 psig. Pressures outside this range may be used as well, however, lower pressures tend to yield lower muzzle energies, while higher pressures may be physically demanding for a user to achieve. Any9suitable gas may be employed as the first gas compressed within the compressed gas chamber, and ambient air may be the most conveniently available first gas. Other mechanisms for compressing the first gas, or sources of the compressed first gas, shall fall within the scope of the present disclosure and/or appended claims. While mechanical compression of the first gas by primary piston8within cylinder8A has been disclosed for providing the first gas at an elevated pressure, other methods or devices may be employed for this purpose while remaining within the scope of the present disclosure and/or appended claims. An external source of compressed gas may be employed, for example, for charging the compressed gas chamber to an elevated pressure during the cocking sequence, prior to charging the back volume with liquefied second gas.

A typical liquefied second gas is liquid carbon dioxide. Any other suitable liquefied second gas may be employed as well. An 88 gram reservoir of liquid carbon dioxide is readily available commercially, for example, and is of a physical size consistent with storage of the reservoir within the stock of the airgun. The stock and/or butt of the airgun may be adapted in any suitable way for facilitating storage of the liquefied gas and/or changing/refilling of the reservoir. While such self-contained storage of the liquefied second gas is not strictly necessary, it is more convenient than the need for an external gas supply characteristic of many previous pre-charged pneumatic airguns. Other suitable sources of liquefied gas may be equivalently employed. The saturation pressure of liquid carbon dioxide (and most other liquefied gases) varies strongly with temperature, ranging from about 600 psi at about 45° F. to about 1000 psi at about 85° F. The hybrid operation of the airgun ofFIGS. 1 through 5typically produces higher muzzle energies than simple adiabatic expansion of either the compressed air or the carbon dioxide alone, and in addition may be optimized to at least partially compensate for the saturation pressure variation to reduce the temperature variation of the airgun muzzle energy. A hybrid airgun as disclosed herein may produce muzzle energies that remain between about 12 ft-lb and about 14 ft-lb over a temperature range between about 45° F. and about 85° F. These muzzle energies are equivalent to muzzle velocities between about 820 ft/sec and about 890 ft/sec for an 8 grain pellet. The muzzle velocity range varies accordingly with the mass of the pellet.

FIG. 6illustrates schematically this compensation mechanism. At lower temperatures, corresponding to the curves601and602, the saturation pressure of carbon dioxide (or other liquefied second gas) is relatively low. There is only a small increase in pressure in the compressed gas chamber, relatively little vaporization of liquefied carbon dioxide, and relatively little motion of secondary piston9within the secondary cylinder. Upon firing, the initial portion of gas flow through the firing valve10, comprising the compressed first gas only flowing at a nearly constant pressure near the second gas saturation pressure, lasts for a relatively long distance of movement of the pellet through the barrel, up to about the region603. Near the region603, the secondary piston9partially disengages from the secondary cylinder, the remaining liquid carbon dioxide vaporizes, and the carbon dioxide begins to flow into the compressed gas chamber and mix and expand with the compressed air (or other first gas). Curve601represents schematically the further substantially adiabatic expansion of the compressed air only, while curve602represents schematically mixing and further expansion of the mixture of air and carbon dioxide. The area under these curves is proportional to the work done on the pellet as it is propelled down the barrel (i.e., the muzzle energy, which in turn with the pellet mass determines the muzzle velocity of the pellet). It is easily seen that the release of the carbon dioxide into the compressed air increases the energy transferred to the pellet, and that both curves601and602represent significantly larger muzzle energies than adiabatic expansion of the compressed air alone (curve620) or of the carbon dioxide alone (curve621).

At higher temperatures, corresponding to curves604and605, the saturation pressure of carbon dioxide may be much higher. There is a relatively larger increase in pressure within the compressed gas chamber, a relatively large amount of vaporization of liquid carbon dioxide, and relatively larger movement of secondary piston9within the secondary cylinder. Upon firing, the initial portion of gas flow through the firing valve10, comprising the compressed first gas only flowing at a nearly constant pressure near the second gas saturation pressure, lasts for a relatively short distance of movement of the pellet through the barrel, up to about the region606. Near the region606, the secondary piston9partially disengages from the secondary cylinder, the (relatively little) remaining liquid carbon dioxide vaporizes, and the carbon dioxide begins to flow into the compressed gas chamber and mix with the compressed air. Curve604represents schematically the further substantially adiabatic expansion of the compressed air only, while curve605represents schematically mixing and further expansion of the mixture of air and carbon dioxide. It is easily seen that both curves604and605represent significantly larger muzzle energies than adiabatic expansion of the compressed air alone (curve620) or of the carbon dioxide alone (curve622).

It may also be seen from the curves ofFIG. 6that hybrid operation may be employed for reducing variation of muzzle energy over a specified temperature range. The high initial pressure and relatively rapid pressure drop characteristic of curve605may yield an area under the curve (i.e., the amount of energy imparted to the pellet) that may be nearly equal to the corresponding area under curve602, which starts at a lower pressure but maintains that pressure over a longer barrel distance and ends at a higher pressure than curve605. Many variables may be optimized against one another for maintaining similar areas under the curves, thereby achieving a desired reduction of the temperature variation of the muzzle energy. Crude equilibrium thermodynamic models may be employed for estimating parameters, but exact calculations are difficult due to the dynamic nature of the expansion and mixing, and due to the nearness of phase transitions and/or critical points of one or more gases involved. It may prove that systematic experimentation is the most efficient route toward finding optimized sets of operating parameters. Parameters to be optimized include (but are not necessarily limited to): identity of first and second gases; volume and pressure of compressed first gas; volume of liquefied second gas transferred; volume of the secondary cylinder9a; mass and friction of the secondary piston9; flow resistance through passages21and22, firing valve10, and around secondary piston9; diameter and length of barrel20; and so forth. It may well be the case that multiple different sets of operating parameters may yield similar muzzle energy performance characteristics, and/or that different sets of operating parameters may be preferred depending on the operating conditions and performance objectives. Such optimizations of hybrid airgun performance shall fall within the scope of the present disclosure and/or appended claims.

Exemplary parameters for a hybrid airgun are:first gas is ambient air compressed to about 500 psig, with the primary piston and primary cylinder being about 1 inch in diameter and yielding a compressed gas chamber about 1.8 milliliters in volume (upon compression);second gas is liquefied carbon dioxide, with the shuttle valve transferring about 0.6 milliliters of liquefied gas;the secondary cylinder is about 0.75 in long with a diameter of about 0.45 in;the secondary piston is about ¼ in long with a diameter of about 0.45 in, is constructed from aluminum, and is bored on its back side to reduce its mass to about 1.5 g;passage21, the passage through firing valve10, and the groove along the secondary piston all have a diameter of about ⅛ in, and passage21is about ¼ in long; andthe barrel is about 20 in long with a diameter of about 0.18 in.

The airgun may be fired using only compressed gas, if no liquefied gas is transferred into the liquefied gas chamber before firing the airgun. This may be achieved by removing pin18A, thereby decoupling the shuttle valve19from the pivot plate15. Alternatively, passage43may be closed with a suitable valve, or the liquefied gas reservoir16may be disconnected or removed. Lever1is pivoted to compress the first gas (ambient air, for example) within primary cylinder8A. Muzzle energy is reduced relative to hybrid use (i.e., both compressed first gas and liquefied second gas); accordingly, such use may be best suited to short distance shooting.

The airgun may be fired using only liquefied gas, if no gas is compressed in the compressed gas chamber before firing the airgun. This may be achieved by sliding the handle2backward and then forward to charge the back volume9B with liquefied gas, without pivoting the lever1to compress gas within the primary cylinder. With no elevated pressure in the compressed gas chamber, secondary piston9immediately moves until it partially disengages from the secondary cylinder, and the second gas vaporizes and pressurizes the compressed gas chamber to an elevated pressure (typically somewhat less than the second gas saturation pressure, since typically all of the liquefied gas vaporizes under these operating conditions). Muzzle energy is reduced relative to hybrid use (i.e., both compressed first gas and liquefied second gas); accordingly, such use may be best suited to short distance shooting. Muzzle energy varies with temperature due to the temperature variation of the elevated pressure of the second gas; accordingly, such use may be best suited for indoor shooting. An 88 gram liquid carbon dioxide reservoir (readily available commercially and of a convenient physical size) may provide hundreds of shots under such use conditions. Other liquefied gas sources may be equivalently employed.

It is intended that equivalents of the disclosed exemplary embodiments and methods shall fall within the scope of the present disclosure. It is intended that the disclosed exemplary embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure.