Crank enabled airgun

Abstract

A spring action airgun includes a crank system with a rack that drives a piston against the force of the spring. The rack is driven by at least one gear that is driven by a crank gear which is turned by rotating a crank handle. The crank system and any extension of the handle combine to provide a useful mechanical advantage to prime the spring and to store energy in the rack return member that urges the rack to return and a rack release mechanism that can be activated to release engagement between the crank handle and the rack so that the rack can rapidly return to the initial position. The crank handle and gears are positioned to the rear of a grip portion, and the rack has an initial position relative to the grip to ensure that the airgun has a desired balance about the grip.

Description

CRANK ENABLED AIRGUNCross-Reference to Related Application

[0001] This application claims priority to US Provisional Application No. 63 / 535,251, filed August 29, 2023, titled ‘CRANK ENABLED AIRGUN,” the entirety of which is hereby incorporated by reference.Technical Field

[0001] The present disclosure relates to the field of air powered projectile launchers. More particularly, the present disclosure relates to air powered airguns.Background

[0002] Airguns and other air powered projectile launchers have been known for many years and are differentiated from firearms in that airguns use compressed air as a primary propellant. This air may be pre-compressed by a pump such as is known in pre-charged pneumatic (PCP) airguns. Such guns include a reservoir that stores air that has been compressed to pressures that are typically well above 100 bars. When such PCP airguns are fired, an amount of air is released from reservoir and used to propel a projectile, such as a pellet, BB, or bullet.

[0003] PCP airguns exhibit relatively limited recoil and can be capable of semi-automatic fire. However, high pressure pumping equipment is required adding cost and expense to the use of such products. Some airguns have mountings allowing a compressed gas storage vessel to be removably mounted to the airgun to allow for rapid recharging of the airguns. Some examples of this type of airgun use compressed air tanks which offer many of the advantages of PCP airguns, however such removably mountable gas storage vessels can be expensive and require additional hardware that can make such airguns costly and complex.

[0004] Other lower cost airguns of this type use replaceable carbon dioxide cylinders. These cylinders store carbon dioxide at a pressure level that allows a portion of the stored carbon dioxide to remain in liquid form. This allowsa significant mass of carbon dioxide to be stored in the cylinder at a much lower pressure than would be required to store an equivalent mass of compressed air in an equivalent storage volume. When fired, some of the gas from the carbon dioxide escapes from the cylinder and some of the liquid CO2 evaporates returning the pressure in the CO2 to a predetermined level. This provides a unique solution that allows repeated shots at a relatively low cost. However, there are limits to the amount of pressure that CO2 can deliver, and CO2 can be temperature sensitive making it less useful depending on temperature conditions.

[0005] In still other airguns, the airgun is provided with an onboard pumping solution. With this design, multiple pump actions are used to build up a volume of compressed air in an onboard storage chamber. In some cases, the storage chamber is sized to receive and store a single shot volume of compressed gas. To make pumping easier, such airguns typically require multiple pumps to store the single shot volume. This limits the ability’ of the shooter to make a rapid follow up shot and can be fatiguing over time when sighting in the airgun or engaging in target practice.

[0006] Another approach is to use a spring to store energy. The most popular spring type airgun is known as a break barrel airgun. In this common airgun, the barrel is pivotably mounted to the receiver and stock of the airgun. In such airguns, pivoting the barrel relative to the stock simultaneously opens the barrel to permit loading a projectile (e.g., pellet) into the barrel and stores energy in a mechanical spring or gas spring that is used to fire the projectile. The barrel is then rotated to close the barrel against the receiver. When the airgun is fired, energy from the spring drives a piston that is located in a compression tube. This drives any air in the compression tube into a much smaller transfer tube and barrel where the now compressed air thrusts the projectile from the barrel. However, the firing energy must be stored in the spring in a single pivot of the barrel relative to the stock. This can require that a user exerts a significant amount of force in pivoting the barrel to prime the piston. This can make break barrel airgun difficult to use by some people. Further, the motion of the piston can create significant vibration and shock that can make aiming difficult and that can have undesired effects on optics and other equipment mounted to such a break barrel airgun.

[0007] According to still other approaches, crank systems for cocking a spring have been proposed. Such systems may require complex and unusual gearing arrangements that must be robust enough to reliably operate against the high forces imposed by the spring and to survive the shock and vibration caused when the piston is fired. Such arrangements therefore make the airgun heavier and more complex. Further, in such systems, the piston itself carries structures that enable the crank to drive movement of the piston against the spring. These structures add mass to the piston that, in turn, creates inertial resistance to the acceleration of the projectile that the spring must overcome when thrusting the piston during firing.

[0008] Examples of the present disclosure are directed to overcoming the deficiencies described above.Summary7of the Invention

[0009] According to examples of the present disclosure, a spring action airgun includes a crank system with a rack that drives a piston against the force of the spring. The rack is driven by at least one gear that is driven by a crank gear which is turned by rotating a crank handle. The crank system and any extension of the handle combine to provide a useful mechanical advantage to prime the spring and to store energy in the rack return member that urges the rack to return and a rack release mechanism that can be activated to release engagement between the crank handle and the rack so that the rack can rapidly return to the initial position. The crank handle and gears are positioned to the rear of a grip portion and trigger mechanism, and the rack has an initial position relative to the grip to ensure that the airgun has a desired balance about the grip.

[0010] According to one example, an airgun is provided comprising a barrel having a bore through which a projectile travels and a compression tube in fluid communication with the bore. A piston is disposed in the compression tube configured for pushing compressed air from the compression tube into the bore. The piston is moveable from a first piston position in the compression tube to a second piston position in the compression tube. A rack is provided incommunication with the piston, and the rack is configured to move the piston from the first piston position to the second position. A crank is provided in communication with the rack and is configured to move the rack from a first rack position to a second rack position, wherein the first rack position corresponds to the first piston position and the second rack position corresponds to the second piston position.

[0011] According to another example, an airgun is provided comprising a piston movable in a compression tube. A resilient member is positioned to apply a bias resisting movement of the piston in a first direction. A sear mechanism is adapted to hold the piston against the force of the resilient member when the piston has been moved a predetermined distance in the first direction and to release the piston so that the bias of the resilient member can drive the piston to compress air in the compression tube. A barrel is provided in which a projectile can be received with the barrel further adapted to receive the compressed air so that the projectile passes through the barrel. A crank mechanism is provided having a handle rotating at a distance from a crank gear to provide a first mechanical advantage and connected to a movable rack by at least one other gear that provides a second mechanical advantage so that rotation of the handle in a first direction causes the rack to move in a first direction from an initial position to engage and drive the piston in the first direction where the piston is held by the sear mechanism. A rack biasing mechanism is provided urging the rack to move in a second direction and a rack release mechanism is adapted to controllably interrupt the mechanical connection between the handle and rack so that causes the rack biasing member to draw the rack to the initial position.

[0012] According to another example, an airgun is provided comprising a stock with a grip with a trigger well proximate to the grip. A compression tube is provided having a first end and a second end, and a piston is disposed in the compression tube. A spring is positioned between the piston and the second end of the compression tube. A sear mechanism is positioned to capture and hold the spring proximate the second end of the compression tube. A crank gear is positioned rear of the grip and trigger well, and a transmission gear is positioned rear of the grip and trigger well where the transmission gear engages the crank gearto provide a mechanical advantage for moving a rack. The rack is movable from an initial position to a priming position and has an engagement surface that engages a piston engagement surface to move the piston against the force of the spring to a position where the piston is captured by the sear mechanism. A rack return mechanism is provided and is activatable after the piston is captured by the sear mechanism.Brief Description of the Drawings

[0013] FIG. 1 is a right-side view of an airgun, according to examples of the present disclosure.

[0014] FIG. 2 is right-side cross section view of an airgun with a projectile in a loading area and in an unprimed state, according to examples of the present disclosure.

[0015] FIG. 3 is a right-side cross section view of the airgun of FIG. 2 with the projectile in a firing position and in an unprimed state, according to examples of the present disclosure.

[0016] FIG. 4 is a right-side cross section view of the airgun of FIG. 2 with the projectile in a firing position and the piston captured by a sear and an enlarged shot volume, according to examples of the present disclosure.

[0017] FIG. 5 shows a right-side cross section view of the airgun of FIG.2 with the projectile in the firing position and piston captured by sear mechanism, according to examples of the present disclosure.

[0018] FIG. 6 shows a right-side cross section view of the airgun of FIG.2 with a projectile stationary and a compressed shot volume, according to examples of the present disclosure.

[0019] FIG. 7 shows a right-side cross section view of the airgun of FIG.2 with a projectile partially thrust down a bore, according to examples of the present disclosure.

[0020] FIG. 8 is a top, right front perspective view of an airgun according to an alternative example of an airgun with cranking system with certain components removed for clarity, according to examples of the present disclosure.

[0021] FIG. 9 shows a top, left, front perspective view of an alternative airgun, according to examples of the present disclosure.

[0022] FIG. 10 shows a top, right front perspective view of a crank gear of the airgun of FIG. 8, according to examples of the present disclosure.

[0023] FIG. 1 1 is a top, right, front perspective view of an example of a transmission gear, additional transmission gear and drive axle, according to examples of the present disclosure.

[0024] FIG. 12 is a top, right, front perspective view of a pawl system for use with the transmission gear and additional transmission gear, according to examples of the present disclosure.

[0025] FIG. 13 is a top, right, front perspective view of a crank handle, according to examples of the present disclosure.

[0026] FIG. 14 is a nght, front, bottom perspective view of another example of a transmission gear, additional transmission gear, drive gear and drive axle of another example of the invention, according to examples of the present disclosure.

[0027] FIG. 15 is a top. cross section view of a double-barreled airgun, according to examples of the present disclosure.

[0028] FIG. 16 is a top, cross section view of an alternative airgun with selected components removed for clarity, according to examples of the present disclosure.

[0029] FIG. 17 is a top, cross section view of another alternative example of an airgun, according to examples of the present disclosure.

[0030] FIG. 18 is a top cross section view of another alternative example of an airgun, according to examples of the present disclosure.

[0031] FIG. 19 is a right-side cross section view of another alternative example airgun, according to examples of the present disclosure.

[0032] FIG. 20 is a right-side cross section view of another alternative airgun, according to examples of the present disclosure.

[0033] FIG. 21 is a right-side cross section view of the alternative example airgun of FIG. 20, according to examples of the present disclosure.

[0034] FIG. 22 is a right-side cross section view of the airgun of FIG. 2 in an unprimed state, according to examples of the present disclosure.

[0035] FIG. 23 is a right-side cross section view of the airgun of FIG. 2 during priming, according to examples of the present disclosure.

[0036] FIG. 24 is a right-side cross section view of the airgun of FIG. 23, in a primed condition, according to examples of the present disclosure.Detailed Description

[0037] The detailed description is set forth with reference to the accompanying figures. The use of the same reference numbers in different figures indicates similar or identical items or features.

[0038] FIG. 1 is a right-side view of an airgun, according to examples of the present disclosure. FIG. 2 is right-side cross section view of an airgun with a projectile in a loading area and in an unprimed state, according to examples of the present disclosure. According to examples, the airgun 10 is comprised of a number of components. Stock 12 is shown as a multipart stock having a right-side stock half 12a shown in FIG. 1 and a left side stock half 12b shown in FIG. 2. This allows components of airgun 10 that are at least in part positioned between rightside stock half 12a and left side stock half 12b to be assembled into either or both of right-side stock half 12a and left side stock half 12b are assembled together.

[0039] The assembly of right-side stock half 12a and left side stock half 12b may be made directly such as by providing co-designed fasteners and mounting points such as Christmas tree fasteners, rivets or other clips, by way of welding such as spot welding, ultrasonic welding, or other forms of interconnection. Alternatively, adhesives, fasteners, clips or other structures may be used to join right-side stock half 12a to left side stock half 12b. According to examples, right-side stock half 12a and left side stock half 12b can be joined together by way connections to components of airgun 10 positioned between rightside stock half 12a and left side stock half 12b including such components as are descnbed later herein. In still other examples, stock 12 can be formed such that right-side stock half 12a or left side stock half 12b are formed from a commonsubstrate such as being formed using milling or other subtractive fabrication techniques, using additive assembly technologies, by casting, molding or injection molding.

[0040] In this example, grip handle 14. fore stock 16 and trigger guard 20 are shown as part of an integral grip unit 24 which in the example illustrated is formed using the same substrate such as might be achieved through milling, other forms of subtractive manufacturing, additive manufacturing, molding, casting. Other processes may be used. In other examples any or all of grip handle 14, fore stock 16 and trigger guard 20 may be formed separately and joined to stock 12 separately. Grip unit 24 is shown joined to stock 12 for movement generally therewith. In the example of FIG. 1, the grip unit 24 is shown optionally joined to stock 12 at points 25, 27 and 29. Referring still to FIG. 1, at point 25, a fastener 26 is used to join stock 12 and grip unit 24. At point 27, the grip unit 24 is captured between stock right half 12a and stock left half 12b when stock right half 12a and stock left half 12b are joined together to complete stock 12. According to one example of this type, stock 12 can have surface features shaped to engage surface features of grip unit 24 to help locate stock 12 and grip unit 24 relative to each other without the use of fasteners.

[0041] In the example of FIGS. 1 and 2, a shoulder stock 18 extends from stock 12 at least in part in a direction away from the muzzle end 46 of a barrel 40 of airgun 10 to a shoulder contact surface 19 that a user of airgun 10 can press up against her shoulder for enhanced stability and recoil management during firing of airgun 10. Shoulder stock 18 can be mounted to stock 12 directly or by way of other components. Shoulder stock 18 can be integral to stock 12, permanently- fixed to stock 12 or removable.

[0042] According to examples, a fire control system 30 is provided. In the example illustrated, fire control system 30 has a trigger 32, and a safety switch 34, and a fire control mechanism 36. According to examples, fire control system 30 includes a fire control mechanism 36 that is responsive to trigger 32 and safety switch 34 to control operation of a sear mechanism 38. According to one example, the fire control mechanism serves to latch the piston to the sear mechanism and subsequently releases the piston when the trigger 32 is pulled.

[0043] According to examples, the trigger 32 is movable within a range of non-firing positions in which fire control mechanism will not fire airgun 10 and a firing position where fire control mechanism 36 enables firing of airgun 10. The safety switch 34 is movable between two positions including a "fire” setting and a ‘’non-firing” position known as a '‘safe” position. When safety switch 34 is in the non-firing position, safety switch 34 prevents trigger 32 from being moved to the firing position. In the example illustrated, this is done by preventing substantial movement of the trigger from an initial non-firing position.

[0044] The airgun 10 also has a barrel 40 with a muzzle end 46 and a breech end 44 with a bore 42 therebetween. In operation, a projectile 6 is thrust from the breech end through bore 42 through the muzzle end 46 toward a target. In examples, the bore may be grooved or ‘’rifled” to impart a spin on proj ectile 6 as projectile is thrust through barrel 40. In the example illustrated in FIGS. 1 and 2, barrel 40 comprises a steel rod having a bore 42 bored out lengthwise from an opening at breech end 44 of the rod to the muzzle end of the rod. Other types of barrels 40 can be used including but not limited to those in which barrel 40 and bore 42 are formed using extruded tubing, welded metal pipes, or formed in other ways using any other processes capable of creating a barrel 40 and bore 42 that can sustain the pressures delivered by airgun 10. Further, barrel 40 can comprise any known structure that can provide a bore 42 through which a projectile 6 can be thrust. In examples bore 42 can be rifled in any know n fashion to impart a spin on a projectile 6 fired through bore 42.

[0045] A breech 50 is positioned at breech end 44 of barrel 40 with a breech passageway 52 generally aligned with bore 42. Breech passageway 52 extends from a loading position to a muzzle end 46 and is generally sized to conform to the size of bore 42 at breech end 44 and aligned therewith so that projectile 6 can be positioned in breech 50 and thrust through breech passageway 52 into bore 42 without substantial damage to projectile 6 or to barrel 40 and without providing an avenue for air to pass by projectile 6. In the example shown in FIGS. 1 and 2, breech 50 provides a barrel sleeve within which barrel 40 can be positioned and aligned relative to breech passageway 40.

[0046] Referring to FIG. 2, a loading system 60 is provided having a loading area 62 into which projectile 6 can be loaded and, in this example, a bolt 64 is positioned in a slide area 66 within which bolt 64 can be moved between a first loading position and the second loading position. In the first loading position, a projectile contact surface 68 is positioned outside of the loading area 62. This allows projectile 6 to be positioned in loading area 62 for loading. In examples, loading area 62 can be designed to receive manually loaded projectiles, or to receive magazines or clips that can store a plurality of projectiles 6 and that can automatically fill an unoccupied loading area 62 with one of the stored projectiles 6. According to examples, breech 50 also has a breech port 58 in which pressurized air can be injected into breech passageway 52.

[0047] In the example of FIG. 2, a spring type power plant is provided having, in this example, a compression tube 80, a piston 92 within the compression tube and a resilient member 108 connected to piston 92. Compression tube 80 has a transfer tube end with a transfer tube 84 extending from a transfer tube input 86 to a transfer tube output 88. Transfer tube output 88 is configured to be in fluid communication with breech port 58 so that any pressurized air or other gas injected into transfer tube 84 is delivered to breech port 58.

[0048] Referring still to FIG. 2, the barrel 40, breech 50 and loading system 60 are configured so that loading system 60 positions projectile 6 at a position between breech port 58 and muzzle end 46 of barrel 40 so that any high-pressure air flowing from breech port 58 drives projectile 6 out of muzzle end 46 of barrel 40. In the example illustrated, an annular bolt seal 70 is positioned in breech passageway 52 proximate loading end 54 in a manner that provides a sealing engagement with bolt 80 to prevent or substantially limit the flow of high-pressure air or other gases through the loading end 54 of breech passageway 52.

[0049] In the example of FIGS. 1 and 2, compression tube 80 has a compression tube channel 90 with a compression piston 92 positioned therein. Compression piston 92 has a compression seal 96 at an end of piston 92 generally facing transfer tube. Piston seal 96 limits the extent to which the shot volume 110 of gas can escape between piston seal 96 and compression tube channel 90. According to examples, compression piston 92 is biased by a biasing member 94to move within compression tube channel 90. Biasing member 94 may be a gas spring, coil spring, or other resilient member or mechanism that can quickly release energy to move compression piston 92 as described herein or as otherwise known in the art of compression pistons during firing.

[0050] In the example of FIGS. 1 and 2, biasing member 94 takes the form of a gas spring with piston 92 including an interior channel 98 with a piston opening 100 at an end of piston 92 opposite from an end of piston 92 at the piston seal 96. A spring seal support 104 extends through piston opening 100 into interior channel sealing interior channel to form a spring volume 102 in which a spring gas is located.

[0051] FIGS. 3 and 4 show the examples of FIGS. 1 and 2 during a priming operation. FIG. 3 is a right-side cross section view of the airgun of FIG. 2 with the projectile in a firing position and in an unprimed state, according to examples of the present disclosure. FIG. 4 is a right-side cross section view of the airgun of FIG. 2 with the projectile in a firing position and the piston captured by a sear and an enlarged shot volume, according to examples of the present disclosure. As is shown in FIGS. 3 and 4. during a priming operation compression piston 92 is moved in a manner that shrinks spring volume 102. This compresses the spring gas in spring volume 102. The spring gas reacts to this change in volume generally in accordance with the ideal gas law by increasing the pressure that the spring gas exerts against piston 92.

[0052] As spring volume 102 shrinks, the spring gas exerts increasing amounts of force against piston 92 increasing the cranking force necessary to rotate crank handle 122. To enable a user to rotate handle 122 within a predetermined range of force during priming, a gear ratio between crank gear 126, transmission gear 134 and drive gear 140 is defined that reduces the peak forces required to move piston 92 against the increasing resistance of the spring gas in spring volume 102 to a level within that required.

[0053] As is also shown in FIGS. 3 and 4, as piston 92 is moved against the bias of the biasing member 94, a shot volume defined by compression tube channel 90, transfer tube end 82 and piston seal 96 enlarges. As this enlarges, ambient air Hows into shot volume 110. Ultimately, piston 92 is moved to alocation where compression piston 92 engages and is ultimately captured by sear mechanism 38. Airgun 10 is designed so that shot volume 110 and therefore the amount of gas in shot volume 110 reaches a desired level when piston 92 is captured by piston sear 94.

[0054] FIG. 5 shows a right-side cross section view of the airgun of FIG.2 with the projectile in the firing position and piston captured by sear mechanism, according to examples of the present disclosure. To further ready airgun 10, a projectile 6 can be put into a position for firing by moving bolt 64 from the first loading position to the second loading position. This thrusts projectile 6 from loading area 62 into interior passageway 52 of breech 50. When in the loaded position, projectile 6 substantially blocks air flow from between breech port 58 and muzzle end 46 of bore 42 while bolt 64 and bolt seal 70 substantially block movement of air flow from breech port 58 toward breech end of bore 42. Bolt 64 is secured in this location during firing, and a shot volume 110 is provided between compression seal 96 and projectile 6 containing ambient air at generally ambient temperatures and pressures.

[0055] When fire control mechanism 36 determines that conditions are met for firing, fire control mechanism 36 causes latch 38 to release piston 92 for movement. When the piston 92 is released, the force applied by the spring gas against piston 92 is much greater than the force applied by the ambient air in shot volume 110. Accordingly, piston 92 is rapidly accelerated to move toward transfer tube input 86. This has the effect of rapidly reducing the size of shot volume 110 and compressing the air in shot volume 110. This, in turn, causes a rapid increase in the pressure that is applied against projectile 6.

[0056] According to examples, the pressure generated by compressing air in the shot volume 110 may reach a number of desired levels for ultimately pushing the projectile 6 through the barrel bore 42. According to one example, the pressure inside the shot volume 110 (and shot volume 111 discussed below) can be above 170 pounds per square inch (PSI) to an upper limit only limited by the manufactured strength of the internal components of the airgun described herein. For example, the pressure generated in the shot volumes 110, 11 1 may equal orexceed 170 PSI, may equal or exceed 180 PSI, may equal or exceed 190 PSI, may equal or exceed 200 PSI, 250 PSI, 300 PSI, and the like.

[0057] FIG. 6 shows a right-side cross section view of the airgun of FIG.2 with a projectile stationary and a compressed shot volume, according to examples of the present disclosure. FIG. 7 shows a right-side cross section view of the airgun of FIG. 2 with a projectile partially thrust down a bore, according to examples of the present disclosure. As is shown in FIG. 7, once projectile 6 begins to travel through bore 42, shot volume 110 increases substantially causing a concomitant decrease in the pressure that gasses in shot volume 1 10 can provide. According to examples, the best results are typically achieved when piston seal 96 reaches a range of positions proximate to transfer tube input 86 before proj ectile 6 has moved substantially from the firing position.

[0058] In examples, projectile 6 and airgun 10 can be defined in a variety of ways to help projectile 6 to resist being moved substantially out of the firing position while piston 92 constricts the shot volume 110. As an initial matter, an inertia of proj ectile 6 causes proj ectile 6 to resist changes in its state of motion. As projectile 6 begins at rest in barrel 40. any forces that tend to urge projectile 6 from a relatively immobile condition to a mobile one must overcome the inertia associated with projectile 6. Additionally, in some cases, airgun 10 may use a proj ectile 6 with a leading head portion and a trailing skirt portion that is generally conically distributed about the centerline of projectile 6 so that, as higher pressures are delivered to projectile 6, these pressures first confront the skirt causing the skirt to flare outwardly to enhance the seal of the projectile 6 against the sides of bore 42 thus providing a pressurized seal between projectile 6 and bore 42.

[0059] As described above, airgun 10 may be configured with a bore 42 having rifling groves, and projectile 6 may be made from a material that permits the rifling grooves to cut tracks into a portion of projectile 6 to impart a stabilizing spin on projectile 6 during firing. Movement of projectile 6 during this process is limited and does not substantially increase shot volume 110. This process requires that a certain amount of force be applied to projectile 6 over a period of time long enough for the tracks to be cut into any potions of projectile 6 in contact with the rifling grooves. Further, in examples, either or both of loading end 54 of borepassageway 52 of breech end 44 of bore 42 may be tapered to form a diameter sufficient to receive proj ectile 6 to a diameter that is smaller than a minimum cross section diameter of at least a portion of projectile 6. This can be done for example and without limitation where projectile 6 takes the form of a slug or bullet that does not incorporate a skirt.

[0060] As should be appreciated, as the pressure of air in shot volume110 is applied to a projectile 6 from the rear and as the cutting of tracks or compression of projectile 6 in bore 42 begins where projectile 6 first contacts rifling grooves or a tapered section of bore 42, such forces travel the length of projectile 6 and then to the edges of the head of the projectile 6 where the tracks are being cut, if any, and where compression occurs, if any. In some types of projectile 6, the forces may be sufficient to modify the profile or shape of projectile 6. Such modification causes less than all of the force applied to projectile 6 to advance the track cutting process and extends the amount of time required for grooves to be cut or such compression to occur.

[0061] These factors help to ensure that there is a period of time between the moment that projectile 6 begins to experience increasing pressure from the air being compressed in the shot volume and the moment that projectile 6 begins rapid acceleration dow n bore 42 toward muzzle end 46. This opportunity is time limited, however, as once the projectile 6 begins substantial movement, shot volume 110 rapidly increases resulting in a rapid loss of compression of shot volume 110 as is illustrated in FIGS. 6 and 7 in the reduced density of air illustrated as reduced visible fill in shot volume 110. It will be appreciated therefore that high projectile speeds can be achieved in an airgun 10 when pressure behind the projectile 6 reaches high levels within the time available before projectile 6 begins substantial movement down bore 42 toward muzzle end 46.

[0062] Accuracy is an important consideration in the operation of a spring gun type airgun. Several factors impact spring gun accuracy. One is the consistency of the peak pressures reached before projectile 6 moves. To the extent that this varies significantly from shot to shot, it becomes difficult for a shooter to anticipate the effects of crosswinds, gravity and elevation on the trajectory of projectile 6. Further, it will be appreciated that because piston 92 must deliver peakpressures within a very short period of time, piston 92 must move quickly and carry significant momentum. This creates a recoil effect in a spring gun that can impact aim while proj ectile 6 is still being guided through bore 42.

[0063] According to examples, airgun 10 of the examples of FIGS. 1 and2 includes a crank system that makes the benefits of resilient power plants available in a form that may be any of more easily primed, more easily cocked, more easily loaded, fired with greater force and fired more accurately. Other benefits are possible. Returning now to FIGS. 1 and 2. crank system 120 will now be described. In this example, crank system 120 comprises a crank handle 122, a crank bar 124, a crank gear 126, an optional crank bearing 128, a transmission gear 134, an optional transmission gear bearing 138, a drive gear 140 and a rack 150 mechanism.

[0064] According to examples, the crank handle and associated components is positioned rearward of the grip 14 and firing system 30. In the example of FIGS. 1 and 2, crank handle 122 is designed to be grasped by the hand of a user of airgun 10 and is joined to a crank gear 126 by way of a crank extension 124. Crank handle 122 and crank extension 124 can be made from any materials suitable for cranking at forces required by spring type power plant 100. In the example shown in FIGS. 1 and 2, crank gear 126 and crank handle 124 are joined by way of a crank axle 128. Crank axle 128 is positioned by a crank journal 130. Crank journal 130 is sized and shaped to receive crank axle 128 and to position crank axle 128 for rotation in a predetermined orientation relative to stock 12 that permits controlled rotation of crank handle 122, crank extension 124 and crank gear relative to stock 12.

[0065] Crank journal 130 can be formed as a part of stock 12 as shown in the examples of FIGS. 1 and 2. However, in other examples crank journal 130 can comprise a separate journal structure that is joined to stock 12 or other components of airgun 10. In examples, crank journal 130 may comprise an arrangement of one or more surfaces of stock 12 shaped to position and align crank axle 128 for rotation as described herein and designed to resist the forces created by use of the crank system 120 as described herein. In other examples, crank journal 130 can be provided by other components of airgun 10 that are joined ormounted to stock 12 directly or indirectly. In examples, crank journal 130 may include a bearing to reduce friction and lower the wear experienced by stock 12 and crank axle 128 during rotation. Such a bearing may be, but is not limited to, a solid surface bearing, a sleeve bearing, a ball bearing, a pin bearing, a magnetic bearing, an air bearing or any other type of bearing.

[0066] In the example shown in FIGS. 1 and 2, crank system 120 further comprises a transmission gear 134, a drive axle and a drive gear 140. In the example shown in FIGS. 1 and 2, transmission gear 134 and drive gear 140 are mounted to drive axle 138. In examples, transmission gear 134 and drive gear 140 are mounted to drive axle 138 such that transmission gear 134, drive gear 140 and drive axle 138 rotate in unison. In other examples, transmission gear 134 and drive gear 140 can be mounted to drive axle 138 so that transmission gear 134 and drive gear 140 can rotate independently of drive axle 138 with, for example, at least one bearing (not show n) linking transmission gear 134 and drive gear 140 to drive axle 138.

[0067] Drive axle 138 is positioned by a drive journal 130. Drive journal132 is sized and shaped to receive drive axle 138 and to position drive axle 138 for rotation in a predetermined orientation and location relative to stock 12 that, in the example of FIGS. 1 and 2 permits transmission gear 134 to engage crank gear 126 so that rotation of crank gear 126 causes rotation of transmission gear 134. Transmission gear 134 and drive gear 140 are linked so that rotation of transmission gear 134 causes rotation of drive gear 140. In examples, drive journal 138 may comprise an arrangement of one or more surfaces of stock 12 shaped to position and align drive journal 132 for rotation as described herein and designed to resist the forces created by use of the crank system 120 as described herein.

[0068] In other examples, drive journal 130 can be provided by other components of airgun 10. In other examples, drive journal can be some other part of airgun 10 that is joined to stock 12 directly or by w ay of other components of airgun 10. In examples, drive journal 132 may include a bearing to reduce friction and lower the wear experienced by stock 12 and drive axle 138 during rotation. Such a bearing may be but is not limited to a solid surface bearing, a sleeve bearing,a ball bearing, a pin bearing, a magnetic bearing, an air bearing, or any other type of bearing.

[0069] In examples, transmission gear 134 and drive gear 140 can be positioned on separate axles and arranged by separate journals provided that transmission gear 134 is caused to rotate when crank gear 126 rotates and provided that transmission gear 134 further causes drive gear 140 to rotate when transmission gear 134 rotates. Crank gear 126, transmission gear 134 and drive gear 140 may be selected so that a first mechanical advantage is provided and a distance between crank gear 126 and crank handle 122 is selected so that the range of force required to rotate crank handle 122 is a fraction of the force required to move piston 92 toward sear mechanism 38. In examples, the system may give a mechanical advantage of between 3: 1 and 10: 1.

[0070] Crank system 120 further comprises a rack system 150. Rack system 150 comprises a rack 152. Rack 152 has a geared surface that is engages drive gear 140. In this example, rack 152 is positioned by a guide system 160 that positions rack 152 so that rack 152 engages drive gear 140 such that rotation of drive gear 140 causes rack 152 to move at least in part between a starting position and a searing position. In the example shown in FIGS. 1 and 2, guide structure 160 is shown having rack guides 162, 164, 166 and 168 that are optionally formed as part of stock 12. In other examples rack guides 162, 164, 166 and 168 can be formed separately and joined to stock 12 by other components of airgun 10.

[0071] When a user wishes to prime airgun 10 so that piston 92 is positioned and latched for firing, the user turns crank handle 122 relative to airgun 10. This moves rack 152 from an initial position shown in FIG. 2 through the position shown in FIG. 3 to the searing position shown in FIG. 4. Piston 92 has a piston engagement surface 148. and rack 152 has a rack engagement surface 158. Rack guide system 160 is configured to cause rack engagement surface to come into contact with piston engagement surface 148 as rack 152 is moved from the initial position toward the searing position and to drive piston 92 against the force of the resilient member 108 toward the searing position.

[0072] According to examples, piston engagement surface 148 is designed to engage rack engagement surface 158 and has sufficient strength toallow rack engagement surface 158 to drive piston 92 against the force of resilient member 108 to a searing position where piston 92 is captured by sear mechanism 38. In the example show n, piston engagement surface 148 is also the structure that is captured by searing system 38. As should be appreciated, other features of piston 92 may be captured by sear mechanism 38. As is also discussed with reference to FIGS. 2, 3 and 4 movement of piston 92 in this direction is resisted by the resilient member 108 with the force of this resistance being highest immediately prior to reaching the latching position.

[0073] Accordingly, crank gear 126, transmission gear 134, drive gear140 and rack 152 are geared such that a mechanical advantage is provided to the person operating crank handle 122. Here the mechanical advantage is about 4:1. However other ratios can be used, for example and without limitation, 6: 1 and 10: 1. Further mechanical advantage may be provided by the length of crank extension 124 between handle 122 and crank gear 126. By varying the length of the crank extension 124, the mechanical advantage may be even larger, for example, 8:1 or more. While a high mechanical advantage is desirable when forces are higher such as just before piston 92 is secured to sear mechanism 38, the number of rotations required to prime airgun 10 will increase in proportion to the extent of the mechanical advantage. Thus, with higher levels of mechanical advantage, more rotation of crank handle 122 is required during priming.

[0074] As discussed generally above, after piston 92 is captured by sear mechanism 38, rack 152 is no longer required to resist the force supplied by biasing member 94 against piston 92. However, rack engagement surface 158 remains in a path of travel of piston engagement surface 148 and must be moved before piston 92 is released by searing system 38 and, in this example, fire control mechanism 36 can include a beartrap mechanism that prevents sear mechanism 38 from releasing piston 92 until rack has been returned to an initial priming position at which rack 152 is positioned so that rack engagement surface 158 is positioned proximate to where piston engagement surface 148 will be positioned after firing of airgun 10. One example of such an initial position is shown in FIGS. 1 and 2. To accomplish this, in examples, rotation of handle 122 in a reverse direction allows rack 152 to be returned to an initial position so that rack 152 returns to aninitial position that is outside of the path of travel of piston catch when piston 92 is released by sear mechanism 38 during firing.

[0075] It will be appreciated that the use of a cranking system 120 having a rack 152 that does not travel with piston 92 limits the mass of piston 92 during firing. This allows for a convenient priming solution while also not significantly increasing the static inertia of piston 92. This allows piston 92 to react more quickly when released by sear mechanism 38 and thus to build up greater pressure in the time available before projectile 6 begins to move. This also reduces the amount of kinetic energy that is available to generate recoil in airgun 10 during firing as compared to systems that add mass to the piston to enable cranking.

[0076] According to examples of FIGS. 1 and 2, an automatic rack return system 112 can optionally be provided. In this example, automatic rack return system 112 comprises a rack return biasing member 114 and a rack release mechanism 116. Rack return biasing member 1 14 is connected to rack 152 and urges rack 152 to move tow ard an initial position shown in FIG. 2. A portion of the energy supplied by a user in rotating crank handle 122 to move piston 92 into engagement with sear mechanism 38 is stored as potential energy in rack return biasing member 114. In the example illustrated, rack return biasing member takes the form of a clock spring.

[0077] According to examples, rack return mechanism 112 is a mechanism that can be activated to eliminate or sufficiently attenuate the forces supplied by drive gear 140 against rack 152 to a level that allows the potential energy stored in rack return biasing member 114 to return rack 152 to the initial position. In the example of FIGS. 1 and 2, the bias supplied by rack return biasing member 114 against rack 152 is principally resisted by any forces supplied at crank handle 122 as transmitted through crank gear 126, transmission gear 134. and drive gear 140. Thus, in this example, rack release mechanism 116 temporarily prevents the forces applied at handle 122 from resisting movement of rack 152 from the position shown in FIG. 4 to the position shown in FIG. 2 where rack engagement surface 158 is positioned outside of the path of travel of piston engagement surface 148 during firing.

[0078] Rack release mechanism 116 can perform these functions in a variety' of ways. In the example of FIGS. 1 and 2, rack return system 112 is configured to move crank gear 126 and crank axle 128 between a first position where crank gear 126 engages transmission gear 134 (shown in FIGS. 2, 3, and 4) and a second position where crank gear 126 is disengaged from transmission gear 134 (shown in FIG. 5). Similarly, in other examples rack release mechanism 116 can enable transmission gear 134 to be movable into or out of engagement with either of crank gear 126 and drive gear 140, and either of rack 152 and drive gear 140 may be movable into and out of engagement with each other. In such examples, rack release 116 moves the relevant gear or rack in a manner that causes engagement during priming and releases this engagement after priming.

[0079] Alternatively, crank gear 126 may be mounted to crank axle 128 by way of a controllable clutch or releasable ratchet system that can be released after priming so that crank gear 126 can spin relative to crank axle 128. Similarly, transmission gear 134 or drive gear 140 may be mounted to drive axle 138 by way of a controllable clutch, releasable ratchet system or other known system that can be released after priming so that transmission gear 134 or drive gear 140. respectively, may spin freely relative to drive axle 138. In still other examples, drive gear 140 may be adapted to spin freely relative to drive axle 138, and rack release mechanism 116 may control a mechanism that links transmission gear 132 to drive gear 140 for common rotation during priming. In other examples, crank handle 122 and crank extension 124 can incorporate a mounting (not shown in the example of FIGS. 1 and 2) that cooperates with crank axle 128 to enable transfer of force from rotation of crank handle 122 and crank extension 124 during priming and that interrupts such a transfer of force to enable return of rack 152 to the initial position.

[0080] In examples, rack release mechanism 116 may be activated and deactivated under manual user control. In examples, rack release mechanism 116 may have a priming sensor mechanism that determines when rack 152 has been moved to complete the priming process. In response, the rack release mechanism 116 may automatically activate so that rack 152 can be moved to the initial position. In examples, rack release mechanism 116 may include a return sensorelement that triggers rack release mechanism 116 to automatically deactivate when rack 152 is returned to the initial position, and thus re-engaging the mechanical connection between handle 122 and rack 152. In still other examples, rack release mechanism 116 may be activated by fire control system 30 or sear mechanism 38 and, in examples, rack release mechanism 116 may be integrated with or share components with fire control system 30 or sear mechanism 38.

[0081] It will be appreciated that, by use of an automatic rack return system 112, a user of airgun 10 will not be required to turn crank handle 122 about crank axle 128 to return the rack 152 back to a starting position. In examples, this may reduce the effects of wear and loading on crank gear 126, transmission gear 134 and drive gear 140. Further, this approach enables crank gear 126, transmission gear 134 and drive gear 140 to be principally operated to drive in only one direction so that these gears do not experience a rapid transition from being driven in one direction to being driven in another direction.

[0082] FIG. 8 is a top, right front perspective view of an airgun according to an alternative example of an airgun with cranking system with certain components removed for clarity, according to examples of the present disclosure. FIG. 9 shows a top, left, front perspective view of an alternative airgun, according to examples of the present disclosure. It will be appreciated that in some examples, the amount of force applied against piston 92 may be significant. In some circumstances, using a single rack 152, as described above, to prime piston 92 can create unbalanced loads that may complicate movement of piston 92 or that may place concentrated loads on portions of crank gear 126. Accordingly, an example of a cranking system 120 shown for the alternative airgun 11 in FIGS. 8 and 9 is arranged to drive piston 92 in a manner that reduces the potential that unbalanced loading or concentrated loadings will interfere with operation of cranking system 120.

[0083] In this alternative example, reducing the potential that unbalanced loading or concentrated loadings may interfere with operation of the cranking system 120 is performed by driving piston 92 with a first rack 152, and a second rack 164. In the example of FIGS. 8 and 9, second rack 153 is shown located in contact with a portion of crank gear 126 separated from the portion of crank gear126 that is in contact with first rack 162. In the example of FIGS. 8 and 9, cranking system 120 is configured to drive both first rack 152 and second rack 153 substantially in parallel when a user turns crank handle 122. This reduces the loads experienced by an interface between first rack 152 and crank gear 126 thus lowering the risk of stress concentrations at that interface.

[0084] Additionally, as is shown in FIG. 9, in the example illustrated, a gear engagement area 180 where crank gear 126 and rack 152 engage is provided on one side of a centerline of piston 92 while an additional gear engagement area 186 is positioned on another side of a centerline of piston 92. This helps to balance the loads applied to crank gear 126 and reduce the extent of any bending moments or other effects of unbalanced loading during priming. A gear engagement area 180 and additional gear engagement area 186 may be generally directly opposite from each other and equally spaced apart from the centerline of piston 92 but is not so limited. That is, any a positioning of a gear engagement area 180 and an additional gear engagement area 186 on opposite sides of centerline, even if not directly oppositional, can reduce the extent of any unbalance.

[0085] As is shown in FIGS. 8 and 9, in this alternative example, piston92 provides a piston engagement surface 148 in a location where movement of rack 152 will bring a rack engagement surface 158 into contact with piston engagement surface 148 during priming as is generally described above. Further, piston 92 provides an additional piston engagement surface 149 in a location where movement of the second rack 153 will bring the rack into contact with an additional piston engagement surface 149 during priming. The piston engagement surface 148 and piston engagement surface 149 may comprise features fabricated into piston 92 or features j oined or mounted to piston 92. In examples, piston engagement surface 148 and piston engagement surface 149 may perform some other function and may extend across a midline of piston 92 so that, for example, a single structure can provide both piston engagement surface 148 and piston engagement surface 149.

[0086] As will be observed in this example, compression cylinder 80 is provided with slots 190 and 191 to permit movement of piston engagement surface 148 and piston engagement surface 149 relative to compression cylinder 80 andthat piston engagement surface 148 and piston engagement surface 149 are provided to project through slots 190 and 191 and into the path of rack 152 and second rack 153, respectively. It will also be observed that piston engagement surface 148 and piston engagement surface 149 are provided so that rack engagement surface 158 and additional rack engagement surface 159 can engage during priming but separate after piston 92 is seared so that rack engagement surface 158 and rack engagement surface 159 can be retracted out of a path of travel of piston engagement surfaces 148 and 149 prior to firing as is generally described above.

[0087] FIG. 10 shows a top, right front perspective view of a crank gear of the airgun of FIG. 8, according to examples of the present disclosure. As is shown in FIGS. 9 and 10, in this example, crank gear 126 has gear teeth in gear engagement area 180 and additional gear teeth in additional gear engagement area 186. Crank gear 126 and transmission gear 134 are further positioned in alternative airgun 11 so that gear teeth engage rack 152 and so that additional gear teeth engage additional rack 153. As is shown in FIGS. 9 and 10, in this example, this outcome is made more readily achievable from a manufacturing standpoint by use of a crank gear 126 with crank gear teeth that extend along a length of crank gear 126 at least through gear engagement area 180 and through additional gear engagement area 186. When such a crank gear is used, lateral alignment of crank gear 126 with both transmission gear 134 and additional transmission gear 136 is assured. In other examples, crank gear 126 can be provided with a segment of gear teeth in gear engagement area 180, an additional segment of gear teeth in gear engagement area 186 and a mechanical linkage causing the segments of crank gear 126 to move generally in concert. In examples, crank axle 128 can provide this mechanical linkage, however other approaches are possible.

[0088] FIG. 1 1 is a top, right, front perspective view of an example of a transmission gear, additional transmission gear and drive axle, according to examples of the present disclosure. That is, FIG. 11 is a top, front, right-side perspective view of a twin gear transmission system 133 with a drive axle transmission gear 134 and an additional transmission gear 136 useful in the example of FIGS. 8 and 9. As is shown in FIG. 11, in this example, transmissiongear 134 and additional transmission gear 136 are larger in diameter than crank gear 126. In this example, transmission gear 134 directly engages both crank gear 126 and rack 152 and additional transmission gear 136 directly engages both crank gear 126 and additional rack 153. An optional spacer 137 is shown in this example between transmission gear 134 and additional transmission gear 136.

[0089] As will be observed, the transmission gear 134 and additional transmission gear 136 are larger in diameter than crank gear 126. The extent of this size differential is determined by the desired mechanical advantage to be provided by crank gear 126 as is generally described elsewhere herein. The presence of the relatively large transmission gear 134 and additional transmission gear 136 can impact the design and appearance of airgun 11. However, as is shown in FIGS. 8 and 9, in examples, transmission gear 134 and additional transmission gear 136 can be separated by a distance that permits a portion of a length of transmission gear 134 and second transmission gear 136 to have an overlap with a portion of a length of other components of airgun 11 such as breech 50 as is shown. In other examples such overlap can include other components, such as fire control system 30, piston 92, and loading system 60.

[0090] FIG. 12 is a top, right, front perspective view of a pawl system for use with the transmission gear and additional transmission gear, according to examples of the present disclosure. Referring back to FIGS. 8 and 9 and now to FIG. 12. according to this example, a pawl system 200 has a pair of pawls 192 and 194. Each of Pawls 192 and 194 has a free end with at least one transmission gear engagement feature 196 shaped to engage teeth of transmission gear 134. As is shown in FIG. 9, pawl 194 has a free end with at least one additional transmission gear engagement feature 198 to engage additional transmission gear 136.

[0091] Pawls 192 and 194 arejoined by abody 202 having apawl control surface 204 and spring mounts 206 and 208. Body 202 is mechanically associated with a pawl axle 210 so that paw l 192, pawl 194, pawl control surface 204, and body 202 rotate together about pawl axle 210. Coil spring 212 and coil spring 214 are mounted to stock 12 (not shown) to urge body 202 to rotate in a first direction about pawl axle 210. Pawl control surface 204 is configured so that a user can exertpressure against pawl control surface 204 to cause body 202 to rotate in a second direction about pawl axle 210.

[0092] Body 202 positions pawl 192 and pawl 194 so that pawls 192 and194 present engagement features 196 and 198 within a predetermined range of angles relative to pawl axle 210. Pawl axle 210 is mounted to airgun 1 1, for example to stock 12 (not shown in FIG. 9) so that engagement features 196 engage or release transmission gear 134 at substantially the same time that engagement features 198 engage or release transmission gear 136. In examples, this predetermined range may be between 0 and 5 degrees. In other examples this predetermined range may be between 0 and 10 degrees. Body 202 is biased by coil spring 212 and coil spring 214 to move pawls 192 and 194 into engagement to prevent unwanted movement of transmission gear 134 and additional transmission gear 136. In examples, pawl system 200 can have engagement features 196 and 198 that may engage transmission gear 134 and additional transmission gear 136 in a manner that permits rotation in a first direction but blocks rotation in a second direction.

[0093] FIG. 13 is a top. right, front perspective view of a crank handle, according to examples of the present disclosure. In this example, crank handle 122 is designed to be grasped by the hand of a user of airgun 10 and is j oined to a crank axle mount 129 (FIG. 10) by w ay of crank extension 124. Crank extension 124 and crank handle mount 146 are joined for common rotation. Crank handle mount 146 has a crank handle mounting surface 147 that may engage either of a crank axle mount 129 and additional crank axle mount 131 as shown in FIG. 10. Crank axle mount 129 and additional crank axle mount 131 are positioned on opposite sides of crank axle 128 and may be co-formed with crank axle mount surface 147 to enable cranking of the crank axle 128 as described herein. This arrangement permits crank handle mount 146 to be mounted on either side of crank axle 128 to enable a user to drive rotation of crank axle 128 from one side or another side of crank axle 128 as may be the user’s preference.

[0094] FIG. 14 is a right, front, bottom perspective view of another example of a transmission gear, additional transmission gear, drive gear and drive axle of another example of the invention, according to examples of the presentdisclosure. This arrangement may be used in the example of FIGS. 1 and 2 to reduce the local stresses experienced by portions of a crank gear 126 that engage transmission gear 134 by transferring a portion of the cranking load to additional transmission gear 136 as generally described above.

[0095] FIGS. 15 - 21 illustrate alternative examples of an airgun as described herein. For purposes of understanding, components, parts or systems that are the same as example airguns illustrated in FIGS. 1 - 14 and 22 - 24 are shown with the same numbering throughout all figures. FIG. 15 is a top, cross section view of a double-barreled airgun, according to examples of the present disclosure. In the example of FIG. 15, the alternate airgun 13 includes stock 12 that is formed by two stock halves 12a and 12b joined together in the same or similar manner as described above with reference to FIGS. 1 and 2. In this example, stock 12 is connected to a first firing system having a sear mechanism 38, barrel 40, breech50, loading system 60, spring type power plant 78 as well as an additional firing system having an additional sear system 39, additional barrel 41, additional breech51, additional loading system 61, additional spring type power plant 79, additional compression tube 81, and additional piston 93.

[0096] This example optionally uses the arrangement of drive axle 138, transmission gear 134, additional transmission gear 136 and drive gear 154 shown in FIG. 14 to drive a rack 152 that has a rack engagement feature 158 configured to engage piston engagement feature 148 of piston 92 and an additional rack engagement feature 159 configured to engage a piston engagement feature 149 of an additional piston 93. In general, this example works in a manner similar to those described elsewhere herein. To prime airgun 13, crank gear 126 is turned to advance rack 152 and therefore drive both of piston 92 and additional piston 93 against the force of a biasing member 94 and biasing member 95 respectively and into engagement with sear mechanism 38 and sear system 39, respectively. Rack 152 is then retracted. Fire control mechanism 36 then controls the release of piston 92 and piston 93 by way of the control that fire control mechanism 36 exerts over sear mechanism 38 and similarly over additional sear system 39 as illustrated and described above. Optionally, an additional fire control system can be provided to control additional sear system 39.

[0097] Airgun 13 of FIG. 15 therefore has the capacity to fire one round from each barrel before it must be reprimed. According to examples, fire control system 36 can be adapted to release one, or the other, or both of pistons 92 and 93 in response to a trigger pull when the safety selector is set to fire. In examples, an additional fire control system 36 can have and additional trigger (not shown) to allow the user to selectively fire a round from either of barrel 40 or additional barrel 41. In examples, the fire control system 36 can incorporate a beartrap mechanism that prevents release of either piston when either rack engagement surface 158 or rack engagement surface 159 is in a path of travel of piston engagement surface 148 or piston engagement surface 149, respectively. It will be appreciated that in this example, the concurrent priming of spring type power plants 78 and 79 is made possible based upon the significant range of mechanical advantage provided by cranking system 120. Use of power plants 78 and 79 additionally create spring volumes 102, 103, in the same manner as described above.

[0098] FIG. 16 is a top, cross section view of an alternative airgun with selected components removed for clarity, according to examples of the present disclosure. In the example of FIG. 16, stock 12 is connected to a sear system 39. additional breech 51, additional spring type power plant 79, additional compression tube 81, and additional piston 93. This example works in a manner similar to those described above, however, in this example, power plant 78 has a transfer tube 87 and additional power plant 79 has a transfer tube 83 that are configured to provide compressed air from shot volume 110 and from an additional shot volume 11 1 in combination to thrust a single projectile 6 from airgun 14.

[0099] In examples, compressed air from each of power plant 78 and power plant 79 can be timed to arrive at projectile 6 achieve a desired pressure profile in thrusting projectile 6. In this regard, the relative timing at which fire control system 30 causes latch mechanism 38 and additional latch mechanism 39 to release piston 94 and the configuration and lengths of transfer tube 84 and additional transfer tube 84 can be configured to achieve such results.

[0100] FIG. 17 is a top, cross section view of another alternative example of an airgun, according to examples of the present disclosure. FIG. 18 is atop cross section view of another alternative example of an airgun, according to examples ofthe present disclosure. As is shown in FIG. 17, two spring type power plants 78 and 79 are primed by way of cocking system 120 and, as is described above, rack 152 can be returned from the priming position to an initial position by using an automatic rack return system 112 having, in this example, a rack return biasing member 1 14, optionally using, in this example, a clock spring 1 18 to urge rack to return to the initial position and a rack release mechanism 116 that, in this example, separates crank axle 128 and crank gear 126 from engagement with transfer gear 134 and additional transfer gear 136.

[0101] As shown in FIGS. 17 and 18, a first firing step occurs when first power plant 78 compresses shot volume 110 into transfer tube 109 and into additional shot volume 111. In the example shown, an optional anti -backflow valve 240 substantially prevents compressed air from returning to shot volume 110 and an exit valve 242 prevents compressed air that has not been further compressed by additional piston 93 and additional compression tube 81 from exiting additional shot volume. This substantially increases the starting pressure in additional shot volume 111.

[0102] FIG. 19 is a right-side cross section view of another alternative example airgun, according to examples of the present disclosure. As is shown in FIG. 19, fire control system 30 (FIG. 2) can cause additional sear mechanism 39 to release additional piston 95 thereby compressing shot volume 111 and increasing the pressure of the gas trapped in additional shot volume 111. In this example, exit valve 272 may have a pressure dependent opening mechanism such as a poppet valve that opens when the pressure of the gas in additional shot volume 111 reaches a desired level. In other examples, exit valve can 272 can take the form of a shutter system that is opened in response to movement of additional piston 93. Other methods and mechanisms for opening exit valve in concert with rising pressure levels in additional shot volume 111. As with the examples illustrated in FIG. 18, first power plant 78 compresses shot volume 110 into transfer tube 107 and into additional shot volume 111. According to examples, however, a timing valve 270 may control entry of this high-pressure air into the shot volume 111 until the exit valve 272 opens, or alternatively, before the exit valve opens if additional pressure in the shot volume 111 is desired.

[0103] FIG. 20 is a right-side cross section view of another alternative airgun, according to examples of the present disclosure. FIG. 21 is a right-side cross section view of the alternative example airgun of FIG. 20, according to examples of the present disclosure. The example airgun 17 shown in FIG. 20. includes stock 12, fire control system 30, barrel 40, breech 50, and loading system 60 a spring action power plant 78, compression tube 80, transfer tube 84, and piston 92 positioned in transfer tube 80. In addition, the example airgun shown in FIG. 20 includes a crank system 120 with a crank handle 120, and crank extension 124. Also included are a crank gear 126 mounted for rotation about a crank axle 128 that is positioned by a crank journal 130 which may be connected to stock 12, a transmission gear 134 and a drive gear 140 mounted for common rotation about a drive axle which may be connected to stock 12. Crank system 120 further includes an automatic rack return mechanism with a rack return biasing member 114 and a rack release mechanism 116. These components work as is generally described above with reference to the example of FIGS. 1 and 2.

[0104] In this example, additional po er plant 79 operates in a similar fashion to power plant 78, however additional power plant 79 is arranged so that additional piston 93 moves within additional compression tube 81 in a direction that is at least in part opposite to the direction of movement of piston 92 in compression tube 80. According to examples, when fired, such oppositely- configured power plants can generate more power while offsetting some of the effects of recoil.

[0105] Accordingly, as shown in this example, cranking system 120 has a rack 152 with an engagement surface 158 as is described above, and piston 92 has a piston engagement surface 148. Movement of the rack in a first direction brings engagement surface 158 into contact with piston engagement surface 148 and thereafter drives piston engagement surface 148 to a position where sear 38 captures piston 92. According to examples, the cranking system 120 has an additional rack 153 with an additional rack engagement surface 159, and an additional piston 93 has an additional piston engagement surface 149. Additional rack 153 is configured so that movement of additional rack 153 in a second direction opposite from the first direction brings additional engagement surface159 into contact with additional piston engagement surface 149 and thereafter drives additional piston engagement surface 149 to aposition where additional sear 39 captures additional piston 93.

[0106] According to this example, the guide system 160 includes guides 1 2, 1 4, 166 and 1 8 that position rack 152 to engage drive gear 140 on one side of drive gear 140 and additional guides 163, 165, 167 and 169 to position additional rack 153 to engage drive gear 140 on an opposite side of drive gear 140 from rack 152. This engagement causes additional rack 153 to move in a direction that at least in part is opposite from a direction of rack 152 when drive gear 140 is rotated.

[0107] In the example shown in FIG. 20, a rack return biasing member 114 is positioned in a path of travel of rack 152 such that movement of rack 152 from an initial position shown in FIG. 20 in the first direction causes a resilient compression of rack return biasing member 114. Similarly, an additional rack return biasing member 115 is positioned in a path of travel of additional rack 153 such that movement of additional rack 153 from an initial position shown in FIG. 20 in the second direction causes a resilient compression of additional rack return biasing member 115. The resilient compression of rack return biasing member 114 and additional rack return biasing member 115 stores potential energy as rack 152 and additional rack 153 are moved to cause piston 92 to be captured by sear mechanism 38 and to cause additional piston 93 to be captured by additional sear mechanism 39.

[0108] When a rack release mechanism 116 is activated, rack return biasing member 114 and additional rack return biasing member resiliently expand and drive rack 152 and additional rack 153, respectively, to their initial positions shown in FIG. 20. However, it will be observed that in this example, both power plant 78 and piston 92 supply compressed air to a barrel port 58 that is proximate to the firing position of projectile 6 and power plant 79 supplies pressurized air to an additional barrel port 59 closer to a muzzle end 46 of barrel 40.

[0109] In this example, when fire control mechanism 36 fires airgun 17, sear mechanism 38 and sear mechanism 39 are released. When this occurs first power plant 78 creates high pressure air that travels through additional transfer port and exits into barrel bore 42 by way of barrel port 58. This thrusts projectile 6along bore 42. However, as projectile 6 travels through bore, the volume between proj ectile 6, bore 42, transfer tube 58, compression tube 80 and a piston seal moved by piston 92 increases rapidly. This in turn rapidly decreases the pressure behind projectile 6. As illustrated in FIG. 21, with the release of sear mechanism 39. the second power plant 79 creates high pressure air that travels through the transfer tube 113 through exit valve 280 and barrel port 59 into bore 42 to push projectile 6 out of the barrel 40.

[0110] FIGS. 22, 23, and 24 illustrated additional example aspects of the airgun 10 of FIG. 2. Referring to FIG. 22, the airgun 10 has a stock 12, fire control system 30, barrel 40, breech 50, and loading system 60. Also included are a power plant 78, compression tube 80, transfer tube 84, piston 92 and piston seal 96 positioned in transfer tube 80, an automatic rack return mechanism 112 and a crank system 120 with a crank handle 120, crank extension 124. In addition, the airgun 10 of FIG. 22 includes a crank gear 126 mounted for rotation about a crank axle 128 that is positioned by a crank journal 130 which may be connected to stock 12, a transmission gear 134 and a drive gear 140 mounted for common rotation about a drive axle 138 shown here joined to stock 12 at a drive axle mount 142. These components work as is generally described above with reference to the example of FIGS. 1 and 2.

[0111] Referring still to FIGS. 22-24, a support surface 222 is positioned on an opposite side of rack 152 from drive gear 140. A support surface 222 is shown as a component of a roller 220 that rotates about a support 224. According to examples, support 224 may be mounted in a slot (not shown) for movement within the slot between a first position and a second position. In examples support surface 222 can be positioned in a priming position where there is a sized drive gap between drive gear and support surface 222 to permit movement of rack 152 through the drive gap. Optionally, the size of this drive gap may include extra space to accommodate a range of variations in the position of rack 152 relative to drive gear 140 along a gap axis such as for example and without limitation to provide 4 to 6 thousandths of an inch of variation in such positioning during priming. The exact extent of permissible variation, however, may be a function of the geometriesof the teeth on first rack surface 224 and teeth on gear 140 and the required efficiency of cranking system 120.

[0112] As is shown in FIGS. 22-24 a pair of guides 166 and 168 are provided in this example to guide rack 152 so rack 152 drives rack engagement feature 158 into contact with rack engagement feature 148 in a desired manner. A minimum gap between guides 166 and 168 can provide limitations on the position of rack 152 between guides 166 and 168 that may be similar to the limitations imposed at a gap between drive gear 140 and support surface 222.

[0113] In this regard, drive gear 140 and support surface 222 can perform functions of guides shown in other examples and can be supported in this by guides 166 and 168 that in this example help to confine movement of rack 152 to ensure efficient engagement between drive gear 140 and rack 152 and to that rack 152 is guided substantially along a path that brings rack engagement surface 158 into a desired contact with rack engagement surface 148. In other examples, support surface 222 can be provided using other structures including but not limited to wheels, slides, guides, and other structures that limit the extent of movement of rack 152 relative to drive gear 140 on an axis other than an axis of movement of the rack 152 used to move piston 92. As is also shown in FIG. 22, when rack 152 is at the priming position, rack return biasing member 114 is resiliently stretched and has stored potential energy that can be released to urge rack 152 to return.

[0114] To reduce the amount of potential energy’ that must be stored in rack return biasing member 114 to enable return of rack 152 and to enable rapid return of rack 152 from the priming position, separation of rack 152 and reduction of the number of components of cocking system 120 that must be moved to return rack 152 can be beneficial. In this example, disengagement of rack 152 from the forces applied through cocking handle 122. crank gear 124, transmission gear 134 and drive gear 140 is provided by enabling rack 152 to separate from drive gear 140.

[0115] According to examples, this is accomplished using a rack release mechanism 116 comprising roller 250, roller surface 222 and a slot 260 within which roller 250 can be moved between a first priming position having roller 250 located so that surface 222 performs the functions described above and a returnposition allowing rack 152 to substantially separate from drive gear 140. Other guides may be configured to both perform the functions described above and to permit rack 152 to be arranged or oriented as necessary to both prime piston 92 and to permit separation of rack 152 from drive gear 140. For example, in the example of FIGS. 22-24, guide 168 is configured to define a minimum gap relative to guide 166 through which rack 152 is thrust in order to properly align rack 152 for priming. However, guide 168 has a taper relative to guide 166 that permits rack 152 to have other orientations during return. Optionally, rack release mechanism 114 can include a biasing mechanism including but not limited to a spring-based mechanism to bias support surface 222 to remain in the priming position unless rack release mechanism 116 is activated.

[0116] When rack return mechanism 116 is activated and support surface 222 is moved to a return position, a return gap between support surface 222 and drive gear 140 comes into existence. The return gap is sufficiently larger than the drive gap to permit movement of rack 152 between support surface 222 and drive gear 140 without substantial engagement with drive gear 140. According to examples, it will also be observed that in this example, rack return biasing member 114 is mounted to a mounting 119 so that rack return biasing member 114 urges rack 152 in both a direction that returns rack 152 to the initial position and in a direction that urges rack 152 against support surface 222 during the return to minimize the risk of contact with drive gear 140.

[0117] In other examples, crank system 120 can interact with airgun 10 in other ways so that operation of crank system 120 can cause operations beyond priming to occur. In this regard, an airgun operating system can be developed that allows the turning of crank system 120 to provide energy’ to enable and optionally synchronize execution of airgun operations such as reloading, resetting fire control system 30 to a state where a pull of the trigger can cause airgun 10 to fire such as by cocking airgun 10.

[0118] For example, referring back to FIG. 22, airgun 10 has a loading system 60 adapted to receive a magazine 232 holding a plurality of projectiles 6 in a manner that permits projectiles 6 to be supplied to a loading area one at a time. Loading system 60 may also have an automatic loading mechanism 252 with aninput wheel 242 that engages support surface 222 of input wheel 254 such that rotation of surface 222 causes rotation of input wheel 254. Loading system 60 receives the energy supplied by input wheel 254 and uses this energy to power loading system 60 so as to cause bolt 64 to retract out of loading area 62 to enable a projectile 6 to be moved into loading area 62 and then to use to drive bolt 64 to thrust projectile 6 from loading area 62 into a firing position (see also FIG. 2).

[0119] In examples, automatic loading mechanism 60 may optionally be arranged so that movement of rack 152 in a first direction can cause bolt 64 to retreat from a firing position to clear the loading position while movement of rack 152 in a second direction can then cause bolt 64 to advance through the loading area to move projectile 6 to the firing position. Automatic loading mechanism can comprise any known type. The operation of crank system 120 cause an automatic type loading system 60 to load a projectile 6 into a firing position and optionally to further position a bolt in a firing position. Further, the operation of crank system can cause elements of a fire control system 30 to reset from a post-firing condition to a ready to fire condition.

[0120] According to examples, crank gear 126, transmission gear 134. drive gear 140 or rack 152 or any other components of crank system 120 may be enabled to interact with other gears or drive surfaces that mechanically interact with such other systems of airgun 10 to power the operation of other systems of airgun 10 to perfonn loading, cocking and other actions necessary for firing a subsequent projectile. In examples, crank system 120 may integrate with fire control system 30 so as to enable a projectile 6 to be fired each time that the crank system 120 is rotated through a predetermined number of revolutions. In examples, synchronization as to when various components of airgun 10 activate or perfonn various functions including but not limited to fire control system 30 and loading system 60 can be achieved based upon interaction of those systems with the operation of crank system 120.

[0121] In other examples, crank system 120 may include a dynamo that generates sufficient electrical charge during operation of crank system 120 to operate components of airgun 10 through electromechanical systems or to supply energy7to accessories such as scopes, red dot sights, and any other electricalsystems. It will also be appreciated that in the examples shown herein, crank system 120 is positioned with crank handle 122, crank extension 124, crank gear 126, crank axle 128, transmission gear 134, drive axle 138 and drive gear 140 and a portion of rack 152 between a grip handle 14 of airgun 10 and a shoulder stock 18 of airgun 1 . This configuration helps to balance the weight of airgun 10 about grip handle 14 at a time of firing.

[0122] It will also be appreciated that in examples, a distance between a center of crank gear and center of grip handle 14 can be between about 75 to 130 mm rearward from the center of grip handle 14. Here too the disconnect between rack 152 and piston 92 at a time of firing assists in achieving this balance in that the weight of rack 152 is backward shifted on return. In other examples a distance between a center of mass of cranking system 120 and a center of mass of barrel and power plant 78 can be between 50 and 150mm. In still further examples a position crank system 120 is selected so that the center of mass forward of handle 14 of an airgun 10 is at least 50% balanced by the weight and positioning of crank system 120 to the rear of grip handle 14.

[0123] The examples shown herein are for illustrative purposes only and are not to be considered as limiting. Unless stated otherwise herein, the drawings are not necessarily to scale. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more examples. In the preceding description, numerous specific details have been provided, such as examples of various configurations to provide a thorough understanding of examples of the described technology. One skilled in the relevant art will recognize, however, that the technology' may be practiced without one or more of the specific details, or with other methods, components, devices, etc. In other instances, well-known structures or operations are not shown or descnbed in detail to avoid obscuring aspects of the technology.Although the subject matter has been described in language specific to structural features, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features described. Rather, the specific features are disclosed as illustrative forms of implementing the claims. While aspects of the present disclosure have been particularly shown and describedwith reference to the examples above, it will be understood by those skilled in the art that various additional examples may be contemplated by the modification of the disclosed machines, systems, and methods without departing from the spirit and scope of what is disclosed. Such examples should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

Claims1. An airgun, comprising: a barrel having a bore through which a projectile travels; a compression tube in fluid communication with the bore; a piston disposed in the compression tube configured for pushing compressed air from the compression tube into the bore, the piston moveable from a first piston position in the compression tube to a second piston position in the compression tube; a rack in communication with the piston, the rack configured to move the piston from the first piston position to the second position; and a crank in communication with the rack configured to move the rack from a first rack position to a second rack position, wherein the first rack position corresponds to the first piston position and the second rack position corresponds to the second piston position.

2. The airgun of claim 1, wherein a movement of the piston from the second piston position to the first piston position generates compressed air in the compression tube, the compressed air communicating to the bore for moving the projectile through the bore.

3. The airgun of claim 2, wherein the compressed air in the compression tube is generated in a shot volume, and the compressed air in the shot volume is compressed to a compression level equal to or greater than 170 pounds per square inch (PSI).

4. The airgun of claim 2, wherein the compressed air in the compression tube is generated in a shot volume, and the compressed air in the shot volume is compressed to a compression level equal to or greater than 180 pounds per square inch (PSI).

5. The airgun of claim 1. further comprising:a compression seal configured for preventing a release of compressed air from the compression tube as the piston moves from a second piston position in the compression tube to a first piston position in the compression tube.

6. The airgun of claim 1 , further comprising a transfer tube disposed between the compression tube and the bore, the transfer tube configured for communicating compressed air from the compression tube to the bore.

7. The airgun of claim 1, further comprising: a biasing member configured to resist movement of the piston from the first piston position to the second piston position.

8. The airgun of claim 1, further comprising: a fire control mechanism including a trigger mechanism configured for releasing the piston from the second piston position to the first piston position; and the crank being positioned rearward of the trigger mechanism.

9. The airgun of claim 8, the fire control mechanism further comprising: a sear configured for holding the piston at the second piston position; and the sear further configured to release the piston to allow the piston to move from the second piston position to the first piston position.

10. The airgun of claim 9, wherein: the sear includes a sear latch configured for holding the piston at the second piston position against the biasing member; and the fire control mechanism in communication with the sear latch, the fire control mechanism configured for releasing the sear latch to release the piston to allow the piston to move from the second piston position to the first piston position.11 . The airgun of claim 1, the crank comprising: a crank handle;a crank extension disposed between the crank handle and a crank gear, the crank gear configured to rotate a transmission gear when the crank handle and the crank extension are rotated; the transmission gear in communication with a drive gear wherein rotation of the transmission gear causes rotation of the drive gear; and the drive gear configured for moving the rack from the first piston position to the second position when the drive gear is rotated by the transmission gear.

12. The airgun of claim 11, the rack comprising: a geared surface in communication with the drive gear wherein rotation of the drive gear causes the rack to move at least in part between the first piston position to the second piston position; and one or more rack guides configured for positioning the geared surface of the rack into communication with the drive gear.

13. The airgun of claim 12, the rack guides are further configured to cause the rack to contact with a piston engagement surface, wherein contact with the piston engagement surface causes the rack to move the piston from the first piston position to the second position.

14. The airgun of claim 13, further comprising: a rack release configured to release the contact of the rack with the piston engagement surface after the piston is moved from the first piston position to the second position; and wherein the rack release causes contact of the rack with the piston engagement surface to be released by causing the crank gear to disengage from the transmission gear.

15. The airgun of claim 13, further comprising: a rack release configured to release the contact of the rack with the piston engagement surface after the piston is moved from the first piston position to the second position; andwherein the rack release causes contact of the rack with the piston engagement surface to be released by causing the transmission gear to move out of engagement with the drive gear.

16. The airgun of claim 1, further comprising: a second a barrel having a second bore through which a second projectile travels; a second compression tube in fluid communication with the second bore; a second piston disposed in the second compression tube configured for pushing compressed air from the second compression tube into the second bore, the second piston moveable from a first piston position in the second compression tube to a second piston position in the second compression tube; and the rack in communication with the second piston, the rack configured to move the second piston from the first piston position in the second compression tube to a second piston position in the second compression tube.

17. The airgun of claim 1. further comprising: a second compression tube in fluid communication with the bore; and a second piston disposed in the second compression tube configured for pushing compressed air from the second compression tube into the bore via a transfer tube in communication with the bore.

18. The airgun of claim 1, the compression tube being a first compression tube, and further comprising: a second compression tube in fluid communication with the first compression tube; and a second piston disposed in the second compression tube configured for pushing compressed air from the second compression tube into the first compression tube via a transfer tube in communication with the first compression tube.

19. An airgun, comprising:a piston movable in a compression tube; a resilient member positioned to apply a bias resisting movement of the piston in a first direction; a sear mechanism adapted to hold the piston against the force of the resilient member when the piston has been moved a predetermined distance in the first direction and to release the piston so that the bias of the resilient member can drive the piston to compress air in the compression tube; a barrel in which a projectile can be received, with the barrel further adapted to receive the compressed air so that the projectile passes through the barrel; a crank mechanism having a handle rotating at a distance from a crank gear to provide a first mechanical advantage and connected to a movable rack by at least one other gear that provides a second mechanical advantage so that rotation of the handle in a first direction causes the rack to move in a first direction from an initial position to engage and drive the piston in the first direction where the piston is held by the sear mechanism; and a rack biasing mechanism urging the rack to move in a second direction and a rack release mechanism adapted to controllably interrupt the mechanical connection between the handle and rack so that causes the rack biasing member to draw the rack to the initial position.

20. An airgun, comprising: a stock with a grip with a trigger well proximate the grip; a compression tube having a first end and a second end; a piston disposed in the compression tube; a spring positioned between the piston and the second end of the compression tube; a sear mechanism positioned to capture and hold the spring proximate the second end of the compression tube, a crank gear rear of the grip; a transmission gear rear of the grip, the transmission gear engaging the crank gear and providing a mechanical advantage for moving a rack;the rack movable from an initial position to a priming position and having an engagement surface that engages a piston engagement surface to move the piston against the force of the spring to a position where the piston is captured by the sear mechanism; and a rack return mechanism activatable after the piston is captured by the sear mechanism.

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