US20200378716A1

US20200378716A1 - Non-provisional patent application for a projectile

Info

Publication number: US20200378716A1
Application number: US16/831,731
Authority: US
Inventors: Graham Wilson Flint
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-03-26
Filing date: 2020-03-26
Publication date: 2020-12-03

Abstract

The subject application is directed to a projectile apparatus and method for use of the same, wherein the apparatus has a first tubular component formed with a lumen and defines an axis, wherein the first component has an open end and a closed end, a second component engaged with the first component to create an assembly, wherein the assembly provides for a sliding axial movement of the second component in the lumen of the first tubular component, and the assembly establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component, a payload mounted on a selected component of the assembly, and a release valve for regulating the gas-filled compression chamber for safety purposes.

Description

PRIORITY STATEMENT

This Application claims the benefit of U.S. Provisional Patent Application No. 62/823657, filed Mar. 26, 2019, as well as U.S. Provisional Patent Application No. 62/966492, filed Jan. 27, 2020, both of which are incorporated by reference herein in their entirety.

BACKGROUND

The present disclosure pertains generally to projectiles for launching by man-powered devices, and more particularly, to projectiles which incorporate pneumatic energy to increase flight speed and velocity, thus translating to increased capability. Furthermore, the subject disclosure ensures the safe and responsible use of these high-powered projectiles by incorporating various safety elements.
A germane factor in evaluating the performance of a man-powered projectile launcher is the velocity at which a projectile is released from the launcher. Regardless whether the projectile is an arrow, a bolt, or a shot cluster, and regardless of whether the projectile is launched by either a vertical bow, crossbow, or other means, the resultant projectile velocity is an important measure of the launcher's performance. In the event, the resultant projectile velocity will be a function of the amount of energy (i.e. the capacity to perform work) that can be stored in the launcher prior to projectile launch, and thereafter used to propel the projectile onto its flight path.
In the context of vertical bows, increased performance has led to the development of compound bows wherein the application of a shooter's physical strength can impart the greatest possible amount of kinetic energy to an arrow or bolt. Accordingly, the bow can most efficiently use muscle power to propel a projectile at high velocity. Meanwhile, the development of projectiles always has been toward devices for which their method of launch can safely accommodate this maximized kinetic energy.
As the power and efficiency of compound bows have steadily increased, the safe transmission of their power to lightweight arrows has been constrained by a trade-off between a bow's strength and its weight. As the launch velocity of an arrow increases, the stresses imposed on a bow can become so great that they can lead to catastrophic failure of the bow, a circumstance which poses a severe risk to the user and to bystanders.
Energy can be classified as being either thermal energy, potential energy or kinetic energy. Of primary interest here are potential and kinetic energy. Potential energy can be possessed by a body by virtue of its position or condition relative to other bodies. For example, an object weighing one pound, when positioned ten feet above a surface prior to being dropped onto the surface, will expend ten foot-pounds of energy when it impacts against the surface. In this example, by virtue of its position relative to the surface, the one pound object had a potential energy of ten foot-pounds. As another example of potential energy, compressed gas can expend potential energy as it is allowed to expand. On the other hand, unlike potential energy, kinetic energy is the energy (work capacity) that a body possesses by virtue of being in motion. Mathematically expressed, kinetic energy is a function of the velocity of the object. Specifically, a particle having a mass “m”, that is moving with a linear velocity “v”, has a kinetic energy that is mathematically expressed as “½ mv²”. As is well known, potential energy and kinetic energy are interchangeable.
The subject innovation is directed to resolving or mitigating the risk of injury to end users, while preserving the integrity of a bow and allowing for more powerful and longer-ranged projectiles.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the present disclosure.

FIG. 1A is a side perspective view of a projectile and associated trajectory, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 1B iluustrates a side perspective view of a projectile and associated trajectory, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 1C provides a side perspective view of a projectile and associated trajectory, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 2 discloses a side view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 3 provides a side perspective view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 4A is a cross sectional view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 4B is a cross section view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 4C is a cross section view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 5A is a cross section view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 5B is a cross section view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 5C is a cross section view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 6 is an exploded cross section side view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 7A is a detail view as enclosed by line 7A-7 in FIG. 6 depicting a side perspective view of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 7B is a detail view as in FIG. 7A showing one or more elements of a projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 8A is a cross section view of an embodiment of a two-phase projectile as in FIG. 6 showing one or more elements of the projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

FIG. 8B is a cross section view of an embodiment of a two-phase projectile as in FIG. 6 showing one or more elements of the projectile, in accordance with one or more element and/or embodiment of the subject disclosure.

SUMMARY OF THE EMBODIMENTS

The subject embodiments provide a projectile apparatus comprising, a first tubular component formed with a lumen and defines an axis, wherein the first component has an open end and a closed end, a second component engaged with the first component to create an assembly, wherein the assembly provides for a sliding axial movement of the second component in the lumen of the first tubular component, and the assembly establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component, a payload mounted on a selected component of the assembly; and a release valve for regulating the gas-filled compression chamber.
In various embodiments, the projectile further comprising a launcher for generating an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.
In other embodiments, during an initial acceleration of the assembly by the driving force, a first kinetic energy is generated for the first component and a second kinetic energy is generated for the second component of the assembly, and a potential energy is generated for the gas in the gas-filled chamber of the assembly.
In additional embodiment, operation of the projectile includes, after the initial acceleration of the assembly, the potential energy of the gas is transferred into kinetic energy with an expansion of the gas to accelerate the payload for separation of the payload from the assembly and to decelerate any remainder of the separated assembly.
In yet additional contemplated embodiments, the apparatus further comprising a pump for filling the gas-filled compression chamber, wherein the pump is attached to the projectile such that only the pump can fill the gas-filled compression chamber.
In some embodiments, the pump is configured for filling the gas-filled compression chamber up to three-hundred pounds-force per square inch.
In further embodiment, the release valve for regulating the gas-filled compression chamber is configured to release pressured air exceeding three-hundred pounds-force per square inch.
Other embodiments detail the second component is a cartridge for holding the payload, and the driving force is generated on the first component, and the payload is separated from the second component, in flight. Furthermore, the payload is mounted on the first component and the driving force is applied to the second component.
In various embodiment, the launcher is man-powered, and selected from the group consisting of a vertical bow, a crossbow, a compound bow, a longbow, and combinations thereof.
In yet further embodiment, the subject projectile further comprising a compression spring in communication with the first tubular component and/or second component, wherein the compression spring acts to communicate a change in a pressure of gas in the gas-filled compression chamber. In this configuration, the change in a pressure of gas in the gas-filled compression chamber corresponds with an expansion or contraction of the second component housed in the first tubular component. Furthermore, the expansion or contraction of the second component housed in the first tubular component is measured from zero to one eighth of an inch as pressure increases from zero pounds-force per square inch to two-hundred and fifty pounds-force per square inch.
The subject innovation also teaches various methods for employing a projectile, one method comprising: providing a projectile, the projectile comprising: a first tubular component formed with a lumen and defines an axis, wherein the first component has an open end and a closed end; a second component engaged with the first component to create an assembly, wherein the assembly provides for a sliding axial movement of the second component in the lumen of the first tubular component, and the assembly establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component; a payload mounted on a selected component of the assembly; and a release valve for regulating the gas-filled compression chamber, providing a launcher configured to launch the projectile; inserting the projectile onto the launcher; and enacting the launcher to launch the projectile.
In various embodiments, the method teaches, that after enactment, the launcher generates an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.
In other embodiments, the method includes, after enactment, an initial acceleration of the assembly by the driving force, a first kinetic energy is generated for the first component and a second kinetic energy is generated for the second component of the assembly, and a potential energy is generated for the gas in the gas-filled chamber of the assembly.
In yet additional embodiment, the method further comprises a pump for filling the gas-filled compression chamber, wherein the pump is attached to the projectile such that only the pump can fill the gas-filled compression chamber. In yet additional embodiments, the pump is limited to three-hundred pounds-force per square inch.
It is further contemplated that the release valve, for regulating the gas-filled compression chamber, releases pressured air when the pressurized air exceeds three-hundred pounds-force per square inch.
In further embodiments, the projectile of the method further comprises a compression spring in communication with the first tubular component and/or second component, wherein the compression spring communicates a change in a pressure of gas in the gas-filled compression chamber.

DETAILED DESCRIPTION

The following description of exemplary embodiment(s) is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.
Processes, techniques, apparatus, and materials as known by one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the enabling description where appropriate. For example, projectile formation and manufacturing may not be discussed in detail, however such processes as known by one of ordinary skill in the art and equivalent methods, processes, and materials would fall within the intended scope of exemplary embodiments. For example, materials, temperatures of formation, sizes of layers, and time increments for steps may be discussed, however other materials, times, temperatures, and sizes are meant to lie within the scope of exemplary embodiments.
In addressing the shortcomings of the existing art and continued advancement of projectile efficiency and performance, one approach involves the design of arrows in which a portion of an arrow's final kinetic energy (and, hence, its ultimate velocity) is stored temporarily in the form of potential energy. This temporary storage within the arrow, in effect, allows an arrow to be launched with a final velocity which exceeds the velocity of the bow's moving parts, thus leading to increased performance while minimizing stress on the bow.
Accordingly, energy can be stored in the form of potential energy within the projectile, wherein pressurized gas within the projectile's shaft can be increased by axial compression within the projectile itself. Subsequent decompression causes the front portion of the arrow to be accelerated in a forward direction; while a detached rear portion is decelerated to near-zero velocity. In this manner, most of a bow's available energy is converted to projectile kinetic energy while, at the same time, subjecting the bow to stresses consistent with the acceleration of a heavier projectile at a lower velocity. This sequential interchange between kinetic energy and potential energy is referred to herein as Acceleration and Separation by Sequential Energy Transfer (“ASSET”).
Prior to the present innovation, the ASSET approach had not been successfully applied to a projectile in the context of crossbows. Failure to make the transition arose for several reasons. First, and foremost is attributed to the far greater power of the crossbow. The internal volume, structural strength, and launch energy of conventional bolts are not compatible with the gas pressures imposed by ASSET technology. This is especially true with respect to the need for greatly increased ASSET-imposed gas pressures. Also, a major concern has been the potentially severe consequences of catastrophic failure. Several such failures were experienced during the present bolt's development.
Referring initially to FIG. 1A, a device in accordance with the present disclosure is shown and is generally designated 10. As shown, the device 10 includes a projectile 12 and a man-powered launcher 14. In the particular case of the device 10 that is shown in FIG. 1A, the launcher 14 is a vertical bow of a type well known in the art. The launcher 14, however, could as well be a crossbow (not shown) or an air gun (not shown), both of which are of types well known in the pertinent art.
As illustrated sequentially in FIGS. 1A, 1B and 1C, a purpose of the present disclosure is to use the launcher 14 to propel the projectile 12 along a flight path (dashed line) 16 toward a target 18. In sequence, FIG. 1A shows the launcher 14 in a configuration for firing the projectile 12. FIG. 1B then shows the projectile 12 as it is being released from the launcher 14. And, FIG. 1C shows the projectile 12, and its payload 20 after it has been separated from the projectile 12 in flight, after launch. In particular, FIG. 1C shows that shortly after launch, the payload 20 continues along the flight path 16 toward the target 18, while the projectile 12, itself, falls to the ground along a separation path (dotted line) 22.
From an energy perspective, FIG. 1A shows a projectile 12 that is ready to be shot from a launcher (vertical bow) 14. In detail, the launcher 14 is configured to have a useable potential energy that can be converted into the kinetic energy of motion for the projectile 12. FIG. 1B on the other hand, shows the projectile 12 at its release point from the launcher 14, after the potential energy in the launcher (FIG. 1A) has been transferred to the projectile 12 as a mixture of potential energy and kinetic energy. In FIG. 1C, the payload 20 is shown after its separation from the projectile 12. In terms of energy transfer, the separation of payload 20 from projectile 12 is caused when a portion of the kinetic energy in the projectile 12 (at launch, FIG. 1B) is pneumatically converted into potential energy of compression inside the projectile 12, and then reconverted into kinetic energy for the payload 20. With this reconverted kinetic energy, the velocity “v” of the payload 20 is increased sufficiently to separate the payload 20 from the projectile 12. Importantly, the payload 20 will substantially maintain the increased velocity “v”.
FIGS. 2 and 3, respectively, show two different embodiments for the present disclosure. In detail, FIG. 2 (with cross reference to FIGS. 4A-C) shows a dual component projectile 12 which includes a proximal component 24 that is nested within a distal component 28. For this embodiment of the present disclosure, a distal component 28 is positioned inside the proximal component 24 (see FIG. 4A). In another embodiment of the present disclosure, which is shown in FIG. 3, the distal component 28′ is positioned on the outside of the proximal component 24′. Both embodiments, respectively, include a nock 30 (30′) that is attached to the proximal component 24 (24′). Further, the embodiment for the device 12′ that is shown in FIG. 3 also includes a plurality of fletches 32 that are attached to the distal component 28′, and a plurality of fletches 34 that can be attached to the proximal component 24′.
With reference to FIG. 4A, it will be appreciated that the proximal component 24 is an elongated tube which is formed with a lumen 36 that extends along the length of the proximal component 24. The lumen 36 has an open end 37, and it has an arresting ring 38 which is located proximate the open end 37. At the other end of the proximal component 24, the nock 30 is affixed to the proximal component 24 to establish a closed end for the lumen 36. FIG. 4A also shows that the distal component 28 of the projectile 12 incorporates a cartridge 40 which may hold a payload 20. For the embodiment of the projectile 12 shown in FIGS. 4A-C, the payload 20 is a shot cluster. Further, the cartridge 40 is shown to include a stabilizing ring 42 and a sealing ring 44 that together maintain an axial alignment for the cartridge 40 as it moves back and forth along the axis 26, inside the lumen 36 of the proximal component 24.
Still referring to FIG. 4A, with the distal component 28 (i.e. cartridge 40) is positioned inside the lumen 36 of the proximal component 24, and a compression chamber 46 is established between the cartridge 40 and the nock 30 of the projectile 12. The sealing ring 44 establishes a substantially air-tight seal for the compression chamber 46. As evidenced by cross reference with FIGS. 4B and 4C, the cartridge 40 is allowed to freely move back and forth inside the lumen 36 of the proximal component 24. Stated differently, it is essential to the operation of the present disclosure that the compression chamber 46 be dimensionally variable.
FIGS. 5A-C show another embodiment of the present disclosure wherein a compression chamber 48 is established in the lumen 36′ of the distal component 28′ of the projectile 12′. Specifically, for this embodiment, a sealing ring 50 is provided on the proximal component 24′ that interacts inside the lumen 36′ with the distal component 28′. With this interaction, a compression chamber 48 is established between the components 24′ and 28′. As with the compression chamber 46 for the embodiment of the projectile 12 (see FIGS. 4A-C), it is essential to the operation of the projectile 12′ of the present disclosure that the proximal component 24′ move freely, and with minimal friction, relative to the distal component 28′, and that the compression chamber 48 thereby also be dimensionally variable.
In an operation of the present disclosure, a driving force 52 (represented by the arrows 52 in FIGS. 4A and 5A) is applied to the projectile 12 (12′) by way of the nock 30 (30′). This occurs during a transformation of the launcher 14 between the consecutive configurations shown in FIG. 1A and FIG. 1B. As shown in FIGS. 4A-C, the effect of this driving force 52 on the projectile 12 is at least three-fold. First, the projectile 12 will be accelerated to a launch velocity “v” for release from the launcher 14. Simultaneously, in a second effect (see FIGS. 4A and 4B), the relatively unrestrained distal component 28 (i.e. cartridge 40) is caused to move forward (i.e. toward nock 30), against the resistance of gas in the compression chamber 46. Thirdly, the gas in the compression chamber 46 is compressed by the relative movement of the distal component 28 (cartridge 40) as the dimensions of the chamber 46 become smaller (see FIG. 4B).
After the projectile 12 has been launched from the launcher 14 (see FIG. 1B), the driving force 52 no longer acts upon the projectile 12 to accelerate the projectile 12. Also, the potential energy that was generated by compressing gas in the compression chamber 46 reaches its maximum. As gas in the compression chamber 46 is then allowed to expand, its potential energy is converted into kinetic energy that is manifested by an increased velocity for the cartridge 40 (and its payload 20) and by a decreased velocity for the proximal component 24. This increasing difference in velocities then causes the payload 20 to separate from the cartridge 40 and to continue along the flight path 16 (see FIG. 1C). At the same time, as gas in the compression chamber 46 expands, the conversion of potential energy into kinetic energy is also manifested as a decrease in the velocity of the proximal component 24.
As intended for the present disclosure, this decrease in velocity of the proximal component 24 will result in the proximal component 24 being launched at a substantially lower velocity than the payload. A special case involves component 24 falling (generally vertically) to the ground along the separation path 22 (see FIG. 1C).
A similar operational scenario occurs for the embodiment of projectile 12′ as shown in FIGS. 5A-C. More specifically, as evidenced by a comparison of FIG. 5A with FIG. 5B, the driving force 52 acts on the nock 30′ to accelerate the projectile 12′. This also compresses gas in the compression chamber 48 in the distal component 28′. In this case, however, the payload 20′ is mounted directly on the distal component 28′ and, thus, both the payload 20′ and distal component 28′ are separated from the proximal component 24′. In this embodiment, expanding gas in the compression chamber 48 acts to increase the velocity of the distal component 28′ (payload 20′) and to diminish the velocity of the proximal component 24′.
FIG. 6 shows another embodiment of a projectile 12 a′ in accordance with the present disclosure. As depicted, the projectile 12 a′ can include a proximal tube 54 and distal tube 56. For the projectile 12 a′, the distal tube 56 is formed with a lumen 58, defines an axis 60, and has an open proximal end 62 and a closed distal end 64. In addition, for the projectile 12 a′, the proximal tube 54 is formed with a lumen 66 and has a proximal end 68 and a distal end 70.
FIG. 6 also shows that a piston 72 which covers the distal end 70 of the proximal tube 54 and is formed with a vent 74. When the projectile 12 a′ is assembled, the piston 72 and distal end 70 of the proximal tube 54 are inserted into the open proximal end 62 of the distal tube 56, as shown. In this arrangement, the proximal tube 54 is engaged with the distal tube 56 to provide for axial movement of the piston 72 in the lumen 58 of the distal tube 56. As shown, this results in the establishment of a compression chamber 76 in the lumen 58 of the distal tube 56, between the axially moveable piston 72 and the closed distal end 64 of the distal tube 56.
Continuing with FIG. 6, it can be seen that a valve 78, which for the article shown is a so-called Schrader valve, is positioned in the lumen 66 at the proximal end 68 of the proximal tube 54. A nock (not shown) can be positioned in the lumen 66 at the proximal end 68 and positioned to extend proximally to the proximal tube 54. For the projectile 12 a′, a source (not shown) of compressed fluid, such as air, can be operably connected to the valve 78 which, in turn, can be employed to regulate the introduction of a filling gas into space 80 in the lumen 66 of the proximal tube 54 between the valve 78 and piston 74. As shown, the space 80 is in fluid communication with the compression chamber 76, through the vent 74 formed in the piston 72, allowing gas flowing through the valve 78 to reach and pressurize the compression chamber 76. For example, in a typical implementation, the space 80 and compression chamber 76 may be pre-pressurized to an initial gauge pressure in the range of about 150 to 250 psi, depending both upon payload weight and launcher force.
With continued reference to FIG. 6, it can be seen that an annular shaped sleeve chamber 82 is established between the inner surface 84 of the distal tube 56 and the outer surface 86 of the proximal tube 54. Axially, the sleeve chamber 82 extends from the friction ring 83 to the piston 72. The friction ring 83 is press-fitted into the open end of the distal tube 56. Also shown, the proximal tube 54 is formed with an opening 88 to establish fluid communication between the space 80 in the proximal tube 54 and the sleeve chamber 82.
As best seen in FIGS. 7A and 7B, an O-ring 90 is disposed between the inner surface 84 of the distal tube 56 and the outer surface 86 of the annular ring 92. Also, the annular ring 92 formed with a ramp surface 94 is positioned in the sleeve chamber 82. The annular ring 92 is permanently sealed to the proximal tube 54. Prior to initial pressurization (FIG. 7A), the O-ring 90 is on the ramp surface 94. During pressurization through the valve 78 (FIG. 6), the sleeve chamber 82 becomes pressurized via the proximal tube opening 88. As the sleeve chamber 82 becomes pressurized, the annular ring 92, together with the proximal tube 54, moves axially in the direction of arrow 96 to compress the O-ring 90 between the inner surface 84 and the annular ring 92 as shown in FIG. 7B. When compressed, as shown in FIG. 7B, a friction force is established between the O-ring 90, the inner surface 84 of the distal tube 56 and the outer surface 86 of the annular ring 92. The friction force between the friction ring 83 and the inner surface 86 of the proximal tube 54 prevents the distal tube 56 from separating from the proximal tube 54, due to pressure in the compression chamber 76 (FIG. 6), prior to launch. On the other hand, the pressure developed in the compression chamber 76 during launch is sufficient, when converted to kinetic energy and momentum, to overcome the friction force provided by the friction ring 83 (FIG. 7A), allowing separation of the proximal tube 54 and distal tube 56.
For this projectile 12 a′ shown in FIG. 6, the vent 74 is sized and/or configured as a constriction such that fluid is able to flow through the vent 74 only at relatively low fluid flow rates. As shown in FIG. 6, the vent 74 can be formed as a small diameter hole (i.e. pinhole) extending through the wall 98 of the piston 72 allowing fluid communication between the space 80 in the proximal tube 54 and the compression chamber 76. In an alternative embodiment, as shown in FIG. 8A, the piston 72′ can include a vent 74′ formed as a labyrinth shaped passageway establishing fluid communication between the space 80′ in the proximal tube 54′ and the compression chamber 76′. More specifically, the labyrinth shaped vent 74′ connects the compression chamber 76′ with the sleeve chamber 82′, and the sleeve chamber 82′ connects with the space 80′ via the opening 88′, as shown.
The pinhole shaped vent 72 (FIG. 6) and labyrinth shaped vent 72′ (FIG. 8A), although constricting, still allow fluid to flow (i.e. at low flow rates) from the space 80, 80′ and into the compression chamber 76, 76′ during initial pressurization. On the other hand, a substantial back flow of gas from the compression chamber 76, 76′ to the space 80, 80′ during launch of the projectile 12 a′ is prevented by the constriction. Because of this, pressure is allowed to build in the compression chamber 76, 76′ during the initial relative movement between the proximal tube 54, 54′ and distal tube 56, 56′ that occurs during launch. This pressure buildup (potential energy) is subsequently imparted to the distal tube 56, 56′ as kinetic energy, in flight, increasing the velocity of the distal tube 56, 56′.
FIG. 8B shows another embodiment of a piston 72″ having an O-ring assembly which includes both an outer ring 100 and an inner ring 102. For purposes of the present disclosure, the outer ring 100 is preferably made of polytetrafluoroethylene (PTFE); more commonly known as Teflon®, a brand name of the DuPont Company. Further, the outer ring 100 can be formed with a diagonal split (not shown) that allows for very slight variations in contraction and expansion of the outer ring 100 during an operation of the projectile 12 a′ (FIG. 6). Also, as an integral part of the O-ring assembly, the inner ring 102 is preferably made of an elastomeric material (e.g. rubber) and it is positioned in the retention groove 104 with the outer ring 100, substantially as shown.
Specifically, in this combination, the inner ring 102 is positioned to urge against the outer ring 100, to thereby force the outer ring 100 into direct contact with the inner surface 84″ of the distal tube 56″. This contact between the outer ring 100 and the distal tube 56″ will create a seal between the sleeve chamber 82″ and the compression chamber 76″ during initial pressurization. However, as envisioned for the present disclosure, in some implementations, slow leakage will occur between the piston 72″ and inner surface 84″ of distal tube 56″ (i.e. leakage past the outer ring 100). As a consequence, this leakage establishes fluid communication between the space 80″ in the proximal tube 54″ and the compression chamber 76″. More specifically, due to the leakage, the compression chamber 76″ is in fluid communication with the sleeve chamber 82″, and the sleeve chamber 82″ connects with the space 80″ via the opening 88″, as shown. With this arrangement, the compression chamber 76″ can be pre-pressurized by pressurizing the space 80″ (i.e. with gas introduced through valve 78 shown in FIG. 6).
More recent versions of the seal between piston 72″ and surface 84″ have dispensed with the need for an elastomeric ring 102. In these later devices, the PTFE ring is precision machined so as to provide a snug slip fit within the distal tube 56″. Such machining can be performed such that a low friction is maintained between 72″ and 84″ while, at the same time, introducing a negligible friction loss to the energy transfer process.
It is important to note that the radial vent 106 in the retention groove 104 can be provided to equalize gas pressure in the compression chamber 76″ with gas pressure against the O-ring assembly (i.e. outer ring 100 and inner ring 102). Specifically, this is done to prevent the rapid build-up of pressure in the gas compression chamber 76″ during a launch from having an adverse effect on the O-ring assembly.
Furthermore, it is germane to the subject innovation to have precise projectile pressurization to maximize trajectory distance, while ensuring safe operation of the projectile.
Accordingly, firing of the projectile when its internal pressurization is too low can cause the device to self-destruct. Conversely, if the fill pressure is too high, the force exerted upon its friction collar becomes excessive; a condition which results in a pneumatic separation of a launch shaft from the rear of its projectile. Although the friction collar has a safety margin of about 3:1, meaning that it would take a minimum of 750 psi to force the collar out during pressurization, whereas our recommended fill pressure is 250 psi.
Primary safety incorporations detailed herein include a uniquely threaded valve thread, which may only be mated to a unique pump which can only pressurize to a specified maximum pressure. In light of the issues outlined above, it is desirable the pressure within an projectile device always be visually apparent. Accordingly, an analog pressure sensor can be incorporated in the form of a compression spring, which controls the extent to which the launch shaft extends beyond the rear end of its projectile. Spring constant (compression versus force) has been selected such that the change in extension increases from zero to approximately one eighth of an inch as pressure increases from zero to a design value in the region of 250 psi.
In one embodiment of the subject projectile device, the launch shaft is provided with a set of axially spaced rings as visual markers, likely screenprinted on the shaft itself. The visual markers are advantageous in indicating the degree of pressurization, which aids in the safer use of the projectile. Alternatively, multicolored rings (graduating from red to green) can be used. Here, pressurization is deemed adequate when the appropriately colored ring becomes visible.
As the subject projectile uses high pressure to allow for maximum performance, the structural integrity of the projectile must be designed and maintained accordingly. As such, circumferentially carbon fiber is employed to ensure adequate integrity. Carbon fiber's primary element is a carbon filament, which is produced from a precursor polymer such as polyacrylonitrile (PAN), rayon, or petroleum pitch. For synthetic polymers such as PAN or rayon, the precursor is first spun into filament yarns, using chemical and mechanical processes to initially align the polymer chains in a way to enhance the final physical properties of the completed carbon fiber. From these fibers, a unidirectional sheet is created. These sheets are layered onto each other in a quasi-isotropic layup, e.g. 0°, +60°, or −60° relative to each other.
From the elementary fiber, a bidirectional or circumferential woven sheet can be created, i.e. a twill with a 2/2 weave. The process by which most carbon fiber is made varies, depending on the piece being created, the finish (outside gloss) required, and how many of the pieces will be produced. In addition, the choice of matrix can have a profound effect on the properties of the finished composite.
Finally, safety concerns become more paramount with the increased pressurization and associated potential damage and/or injury. Accordingly, the subject innovation incorporates a carbon fiber geometry which ensures safe and responsible use of the projectile.
The addition of a selectable launch shaft ballast weight allows the terminal velocity of the launch shaft to be adjusted so as to ensure safe operation. In addition, a built-in pressure sensor is contemplated in the projectile, allowing a method for warning an end user that the pressure exceeds safety standards. The subject projectile and/or projectile launcher will have a nock adaptor employing an unconventional air fill valve. The air fill valve may only be paired with a pump capable of complimenting the air fill valve for pressurization. The proprietary air fill valve is configured for use with the complimenting pump only, thus ensuring only limited pressure is delivered to the air fill valve, wherein the limited pressure is within a prescribed safe range.
In addition, as the transport of projectiles under pressure adds additional risk and potential harm, the complimenting pump is configured to be transportable to allow for transport of the projectile in the unpressurized state, further adding to the safety element. Once the end user has reached the designated location for using the projectile, the pump may then be engaged with the projectile for pressurization.
Furthermore, the nock cap may incorporate a custom nock contour for various bolt manufacturers, which allows for adaptability of the projectile to mate with the desired bolt, thus increasing the utility and adaptability of the projectile, while ensuring the end user uses the complimenting pump. Other design refinements include a conical air blast deflector on the launch shaft piston; a feature which reduces acoustic signature in the forward direction. Also, the subject projectile can use an o-ring-equipped forward shaft insert. This allows the interchange of field points and broad heads in the field. As a safety feature, the o-ring forward shaft allows for depressurization of the projectile without the need to discharge the weapon.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the innovation is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions.
The present invention relates to the design of a novel crossbow projectile. Key features include: A means for accommodating shaft gas pressures in the neighborhood of 10,000 psig. A shaft design which accommodates the higher stresses resulting from the heavy projectiles which are essential in the hunting of large game. The adoption of non-standard screw threads on the device-specific pump used to pressurize bolts; a feature that prevents the user from employing an unsafe fill pressure. A rapid means for depressurizing and collapsing the bolt; a feature which greatly improves safety and portability in the field. A built-in pressure sensor which immediately alerts the user to a loss in shaft pressure; a circumstance which also relates to device safety. A conical air blast deflector that reduces the crossbow's down range acoustic signature. The incorporation of an adjustable ballast weight which limits the final velocity of the launch shaft; thereby increasing the likelihood of shaft recovery.

Claims

1. A projectile apparatus comprising:

a first tubular component formed with a lumen and defines an axis, wherein the first component has an open end and a closed end;

a second component engaged with the first component to create an assembly,

wherein the assembly provides for a sliding axial movement of the second component in the lumen of the first tubular component, and the assembly establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component;

a payload mounted on a selected component of the assembly; and

a release valve for regulating the gas-filled compression chamber.

2. The projectile of claim 1, further comprising a launcher for generating an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.

3. The projectile of claim 2, wherein, during an initial acceleration of the assembly by the driving force, a first kinetic energy is generated for the first component and a second kinetic energy is generated for the second component of the assembly, and a potential energy is generated for the gas in the gas-filled chamber of the assembly.

4. The projectile of claim 3, wherein, after the initial acceleration of the assembly, the potential energy of the gas is transferred into kinetic energy with an expansion of the gas to accelerate the payload for separation of the payload from the assembly and to decelerate any remainder of the separated assembly.

5. The projectile of claim 1, further comprising a pump for filling the gas-filled compression chamber, wherein the pump is attached to the projectile such that only the pump can fill the gas-filled compression chamber.

6. The projectile of claim 5, wherein the pump is configured for filling the gas-filled compression chamber up to three-hundred pounds-force per square inch.

7. The projectile of claim 1, wherein the release valve for regulating the gas-filled compression chamber is configured to release pressured air exceeding three-hundred pounds-force per square inch.

8. The projectile of claim 1, wherein the second component is a cartridge for holding the payload, and the driving force is generated on the first component, and the payload is separated from the second component, in flight.

9. The projectile of claim 1, wherein the payload is mounted on the first component and the driving force is applied to the second component.

10. The projectile of claim 1 wherein the launcher is man-powered, and selected from the group consisting of a vertical bow, a crossbow, a compound bow, a longbow, and combinations thereof.

11. The projectile of claim 1, further comprising a compression spring in communication with the first tubular component and/or second component, wherein the compression spring acts to communicate a change in a pressure of gas in the gas-filled compression chamber.

12. The projectile of claim 11, wherein the change in a pressure of gas in the gas-filled compression chamber corresponds with an expansion or contraction of the second component housed in the first tubular component.

13. The projectile of claim 12, wherein the expansion or contraction of the second component housed in the first tubular component is measured from zero to one eighth of an inch as pressure increases from zero pounds-force per square inch to two-hundred and fifty pounds-force per square inch.

14. A method for employing a projectile, the method comprising:

providing a projectile, the projectile comprising:

a second component engaged with the first component to create an assembly,

a payload mounted on a selected component of the assembly; and

a release valve for regulating the gas-filled compression chamber,

providing a launcher configured to launch the projectile;

inserting the projectile onto the launcher; and

enacting the launcher to launch the projectile.

15. The method of claim 14, wherein, after enactment, the launcher generates an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.

16. The method of claim 15, wherein, after enactment, an initial acceleration of the assembly by the driving force, a first kinetic energy is generated for the first component and a second kinetic energy is generated for the second component of the assembly, and a potential energy is generated for the gas in the gas-filled chamber of the assembly.

17. The method of claim 14, further comprising a pump for filling the gas-filled compression chamber, wherein the pump is attached to the projectile such that only the pump can fill the gas-filled compression chamber.

18. The method of claim 17, wherein filing the gas-filled compression chamber with the pump is limited to three-hundred pounds-force per square inch.

19. The method of claim 14, wherein the release valve for regulating the gas-filled compression chamber releases pressured air when the pressurized air exceeds three-hundred pounds-force per square inch,

20. The method of claim 14, wherein the projectile further comprises a compression spring in communication with the first tubular component and/or second component, wherein the compression spring communicates a change in a pressure of gas in the gas-filled compression chamber.