Piston/rocket projectile with frangible casing

Abstract

A piston/rocket projectile for use within a launcher system having a barrel and method of firing such are presented herein. The projectile comprises a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston. A casing is secured to the base of the projectile body, enclosing the piston and vents prior to the ignition of propellant, and a frangible joint is disposed between the casing and the base of the projectile body. Upon ignition of propellant in the combustion chamber, the projectile piston is forced against the casing and causes the frangible joint to break, leaving the casing in the barrel. After the piston completes exertion of propulsion force against the casing, combustion products of the ignition of propellant are expelled through the vents out of a lower end of the projectile and solid combustion byproducts from the ignition of the propellant are collected in the casing.

Claims

1. A projectile for use with a launcher system having a barrel comprising: a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston; a casing secured to the base of the projectile body enclosing the piston and vents prior to the ignition of propellant; and a frangible joint between the casing and the base of the projectile body, wherein, upon ignition of propellant in the combustion chamber, the piston is forced against the casing and causes the frangible joint to break, leaving the casing in the barrel such that after the piston completes exertion of propulsion force against the casing, combustion products of the ignition of propellant are expelled through the vents out of a lower end of the projectile and solid combustion byproducts from the ignition of the propellant are collected in the casing.

2. The projectile of claim 1 wherein the frangible joint comprises a flange in one of the casing or projectile base secured in a groove in the other of the casing or projectile base, the flange being shearable upon a predetermined force to separate the casing from the projectile body upon ignition of propellant in the combustion chamber and extension of the piston out of the projectile base.

3. The projectile of claim 1 wherein the vents are non-circular and are formed in part by walls of an inner surface of the projectile body and in part by an outer surface of the piston.

4. The projectile of claim 1 wherein the projectile body is formed of an electrically non-conductive material and propellant in the combustion chamber is ignited electrically, said projectile further including an electrode extending through the projectile body and into the combustion chamber.

5. The projectile of claim 4 further including a gel-type propellant in the combustion chamber, and wherein the electrode extends into the gel-type propellant in the combustion chamber.

6. The projectile of claim 1 wherein the projectile includes a nose portion at an end opposite said projectile base, said nose portion having a rupture capsule disposed in an interior surface of said nose portion, wherein said nose portion is configured to open said rupture capsule upon contact with a target.

7. The projectile of claim 6 wherein the nose portion further includes tear joints on an exterior surface to facilitate opening of said rupture capsule.

8. The projectile of claim 6 wherein a diameter of the nose portion is smaller than a diameter of said projectile body.

9. The projectile of claim 6 further including sticky chip on said projectile body such that said sticky chip will adhere to a target upon impact with said projectile.

10. A method of launching a projectile from a launcher system having a barrel and a breech comprising: providing a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston; providing a casing secured to the base of the projectile body by a frangible joint between the casing and the projectile body base, the casing enclosing the piston and vents prior to the ignition of propellant; igniting propellant in the combustion chamber, causing the piston to be forced against the casing and causing the joint to break, thereby leaving the casing in the barrel such that after the piston completes exertion of propulsion force against the casing, combustion products of the ignition of propellant are expelled through the vents out of a lower end of the projectile and solid combustion products from the ignition of propellant are collected in the casing.

11. The method of claim 10 wherein the frangible joint comprises a flange in one of the casing or projectile base secured in a groove in the other of the casing or projectile base, and wherein the flange is sheared upon a predetermined force by the piston to separate the casing from the projectile body upon ignition of propellant in the combustion chamber and extension of the piston out of the projectile base.

12. The method of claim 10 wherein the flange in the casing is sheared upon a predetermined force by the piston to separate the casing from the projectile body upon ignition of propellant in the combustion chamber and extension of the piston out of the projectile base.

13. The method of claim 10 wherein the vents are non-circular and are formed in part by walls of an inner surface of the projectile body and in part by an outer surface of the piston by extrusion, and wherein the vents are exposed before the piston reaches the limit of its travel within the projectile body.

14. The method of claim 10 wherein the projectile body is formed of an electrically non-conductive material and propellant in the combustion chamber is ignited electrically, said projectile further including an electrode extending through the projectile body and into the combustion chamber.

15. The method of claim 14 further including a gel-type propellant in the combustion chamber, and wherein the electrode extends into the gel-type propellant in the combustion chamber, said method including igniting the gel-type propellant in the combustion chamber.

16. A projectile for use with a launcher system having a barrel comprising: a projectile body formed of an electrically non-conductive material having a combustion chamber for propellant, the combustion chamber having a gel-type propellant therein and an electrode extending through the projectile body and into the combustion chamber for electrically igniting the gel-type propellant, a piston moveable to extend out a base of the projectile as a result of ignition of said gel-type propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of said gel-type propellant out of the projectile base after initial movement of the piston; a casing secured to the base of the projectile body enclosing the piston and vents prior to the ignition of the gel-type propellant; and a frangible joint between the casing and the base of the projectile body, wherein, upon ignition of the gel-type propellant by the electrode in the combustion chamber, the piston is forced against the casing and causes the joint to break, leaving the casing in the barrel such that after the piston completes exertion of propulsion force against the casing, combustion products of the ignition of the propellant are expelled through the vents out of the lower end of the projectile and solid combustion byproducts from the ignition of the propellant are collected in the casing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may bests be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:

(2) FIG. 1 is a side view of the projectile of the present invention.

(3) FIG. 2 is a cross-sectional view taken along the A-A axis of FIG. 1.

(4) FIG. 3 is a bottom view of the projectile of the present invention having the casing removed for clarity.

(5) FIG. 4 is a perspective view of the lower inner sleeve of the present invention.

(6) FIG. 5 is a cross-sectional view of the projectile as initially loaded within the launching system, including a schematic presentation of the launching system's circuit diagram.

(7) FIG. 6 is a cross-sectional view of the projectile within the launching system after initial ignition of the projectile.

(8) FIG. 7 is a cross-sectional view of the projectile within the launching system as the projectile is leaving the launching system.

(9) FIG. 8 is an enlarged cross-sectional view of the casing and body configuration of the projectile of the present invention.

(10) FIG. 9 is an enlarged cross-sectional view of the casing and body configuration of the projectile after firing of the projectile within the launching system.

(11) FIG. 10 is an enlarged cross-sectional view of the projectile ogive section.

(12) FIG. 11 is a side view of the electrically non-conductive layer.

(13) FIG. 12 is a cross-sectional view taken along the A-A axis of FIG. 11.

(14) FIG. 13 is a top view of the electrically conductive layer.

(15) FIG. 14 is a cross-sectional view taken along the A-A axis of FIG. 13.

(16) FIG. 15 is a perspective view of an embodiment of the non-lethal projectile of the present invention.

(17) FIG. 16 is an enlarged cross-sectional view of the nose of the projectile in FIG. 15.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

(18) In describing the embodiment of the present invention, reference will be made herein to FIGS. 1-16 of the drawings in which like numerals refer to like features of the invention.

(19) Certain terminology is used herein for convenience only and is not to be taken as a limitation of the invention. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “upward,” “downward,” or the like, merely describe the configuration shown in the drawings. Indeed, the referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.

(20) Additionally, in the subject description, the words “exemplary,” “illustrative,” or the like, are used to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or “illustrative” is not necessarily intended to be construed as preferred or advantageus over other aspects or design. Rather, the use of the words “exemplary” or “illustrative” is merely intended to present concepts in a concrete fashion.

(21) The exemplary piston/rocket projectile 40 of the present invention as shown in FIGS. 1 and 2 includes a cylindrically shaped outer body 60 having an ogive or blunt shaped dome 62 at its nose or front end and a casing 50 secured to body 60 at its opposite, lower or base end to seal the projectile base 61. Casing 50 has a flat base 59 and on its periphery above the base, an extractor groove 58 and an outer cylindrical extension 54 above the groove. Inserted within body 60 are lower inner sleeve 70 and upper inner sleeve 80, which each have cylindrically shaped inner surfaces that slidingly receive piston 90, which may slide therein with a slight interference. Body 60 may be made from any suitable material such as a composite or polymer. Lower inner sleeve 70 may be made from a metal or alloy such as extrudable 6061-T6 aluminum. Upper inner sleeve 80 may be made from a metal or alloy such as steel. Piston 90 may be made from a metal or alloy such as 7075-T6 aluminum. Casing 50 may be made from a metal or alloy such as aluminum or may have a composite construction of a polymer with a metallic insert molded into a plastic casing body with annular ring, as discussed further below.

(22) The connection or joint between projectile body 60 and casing 50 is achieved by an interlocking, annular structure comprising a cylindrical extension 64 extending from the lower or rear end of body 60 within an outer cylindrical extension 54 extending up or forward from casing 50, with the outer diameter of extension 54 being comparable to the outer diameter of projectile body 60, as shown in FIGS. 2 and 8. Outwardly extending body flange 66 and inwardly extending casing flange 56 fit snugly within complimentarily shaped grooves in casing extension 54 and body extension 64, respectively. The flanges and grooves, positioned adjacent the outer diameter of casing 50 and body 60, are configured to be able to have a snap fit as they are pushed together during assembly of the casing to the projectile body. While the above flange and groove configuration are preferred, other configurations are not precluded, for example, having the body flange extending inwardly and casing flange extending outwardly. It should be understood by a person skilled in the art that any configuration sealing the casing 50 and the body 60 could be permissible, including acceptance of a flange within an annular channel.

(23) Lower inner sleeve 70 is received in a tight fit within the lower portion of outer body 60. Upper inner sleeve 80 is likewise received in a tight fit within the upper portion of the outer body 60, and the lower end of sleeve 80 is stepped in with a smaller diameter to fit within the upper end of sleeve 70. In some embodiments, upper sleeve 80 and lower sleeve 70 may be of a single construction within body 60. Piston 90 has a cylindrical elongated body sized to slide freely within the inner bore of lower inner sleeve 70 and a cylindrical head 96 of larger diameter sized to slide freely within the inner bore of upper inner sleeve 80. The cylindrical construction of piston 90 and head 96 is exemplary only, and may be of any construction so that sliding within the inner bore of sleeve 80 is permitted. As depicted in FIGS. 3 and 4, channels 72 are formed in the inner surface of lower inner sleeve 70, for example by extrusion along the entire inner bore thereof, and are enclosed along their length at the upper end in part by the stepped-in portion of upper inner sleeve 80 and at the lower end in part by the outer surface of the elongated body of piston 90. The channels 72 in the lower portion of sleeve 70 form in cross-section non-circular passageways along approximately one-half of the length of the sleeve 70. Three of these channels 72 are shown in the example as a “Y” shape equally spaced around the periphery of piston 90. These lower end channels 72 and the mating portions of the outer wall of the piston 90 elongated body form gas vents, as will be described further below.

(24) Combustion chamber 100 as shown in FIGS. 2 and 5 is formed between the upper end of the interior of upper inner sleeve 80 and the upper end 94 of piston head 96. Propellant 101 in combustion chamber 100 may be electrically ignited by applying a current from a battery 132 and capacitor 134 power source via a circuit extending along or through the launcher barrel (FIG. 5). As shown in the schematic, one leg of the circuit in the launcher barrel connects via contact 126 with an upper portion of projectile body 60. A metal electrode 110 or any other suitable conductive means is provided with an exposed outer end portion adjacent ogive 62 that connects to contact 126 and extends inwardly and has a 90-degree turned contact tab that travels through an opening in the forward end of upper inner sleeve 80. The opposite inner end portion 112 of electrode 110 makes contact with an electronic primer at the forward end of combustion chamber 100. Electrode 110 may be inserted or molded into body 60. The other ground leg of the circuit in the launcher barrel includes contact 128 that connects with casing 50, which is in contact with the lower end 92 of piston 90. If casing 50 is not made from a metal or alloy, it may have a composite construction of a polymer or similarly non-conductive material with a metallic electrode slug or terminal bridge insert forming contact 128 molded therein and extending from the outer surface of casing base 59 to the casing inner surface 52 for conductivity with the lower end of piston 90. Because of the use of electrode 110 as the first circuit leg, no electrically insulating coating is needed on piston 90 as part of the ground leg.

(25) When projectile 40 is loaded into launcher 120, ignition of the propellant is achieved by closing switch 130 and discharging the ignition circuit which travels in one leg from a contact 126 in the launcher barrel through electrode 110 and in the other ground leg from a contact 128 in the launcher barrel breech through the casing 50 and piston 90. For example, a 150V capacitor 134 may be discharged to supply current to energize a primer, such as the Remington ETRONX primer, and ignite the propellant charge in the combustion chamber 100. It should be understood by those skilled in the art that the use of 150V capacitors to energize Remington ETRONX primers are only one example of providing ignition of a propellant charge within a combustion, and that other ways of providing a propellant charge within a combustion chamber are not precluded.

(26) FIG. 6 depicts the initial piston thrust portion of the launch of projectile 40 from launcher 120. As the propellant explodes, the hot combustion gases 102 force piston 90 downward. Instead of directly contacting the barrel breech face as in U.S. Pat. No. 8,342,097, piston lower end 92 instead contacts casing inner surface 52 and applies force against the casing 50 structure to propel the remainder of the projectile forward. The joint between the projectile body 60 and casing 50 provides a type of shear flange in which column thickness of the joint materials regulates shear strength to control the release of the projectile from the casing at optimal internal pressures. In the embodiment shown in FIG. 9, the casing flange 56 is configured to be frangible, i.e., to shear at a desired force substantially along line S, for example, 5 to 8 lbs. of linear force in the direction along the axis of the projectile. The joint may be configured via selection of materials and shape and thickness to achieve any desired separation force. Alternatively, the projectile body flange 66 may be configured to be frangible to shear along line S′. Other frangible geometrical configurations may be used in place of the joint configuration shown herein. For example, the shear flange may be interrupted and extend around only a portion of the circumference of the casing and projectile body, to reduce the force needed to separate the joint. The length of casing 50 relative to the length of projectile body 60 may be increased beyond that shown, so that the height of casing extension 54 may be greater than that depicted in the drawings. Thus, it will be understood by a person skilled in the art that other configurations of releasing a casing from a projectile are not precluded, and the above cited configurations are exemplary. A shear flange might be obsoleted because of retention within the base cap; or might be minimized in elevation to just hold the piston in assembly.

(27) After the shear flange S of the joint between casing 50 and projectile body 60 is broken, projectile 40 is free to move forward by virtue of the force applied by piston 90 out of the projectile base 61 against casing 50, the latter being thrust against and remaining in the breech of the launcher barrel. As the piston initially travels downward and rearward, mechanical force of the piston thrust alone propels the projectile 40, which initially carries with it the sheared-off casing flange portion 56 of casing extension 54. As shown in FIG. 6, before the piston reaches the limit of its travel, at approximately 90% of the total distance of travel of the piston, the upper or forward end 94 of the piston passes the lower end of upper inner sleeve 80 and reaches the forward end of gas channels or vents 72 formed in lower inner sleeve 70, which extend to the lower end of projectile body 60. The exposure of the three channels 72 shown in the “Y” shape around the periphery of piston 90 as the top of piston passes by act as valves for the second stage propulsion of the projectile. Once channels and vents 72 begin to open to the exploding propellant, the combustion products 102 expel out of the lower end of the vents 72 of the projectile, and further expel rocket energy from the ignition charge. Piston 90 continues to move downward until it is fully extended, as shown in FIG. 7. Once the piston 90 is fully extended and the piston base 92 lifts off and separates from contact with the casing 50, the force of the combustion gases 102 out of the base 91 of projectile 40 alone add further force to propel the projectile from the launcher barrel 124, as shown in FIG. 7. For non-lethal rounds, the projectile speed may be in the range of about 300-400 ft./sec. The barrel may have a rifled interior surface to impart twist to the projectile as it moves through during the rocket propulsion stage of launch.

(28) With a typical charge of 35 mg of gunpowder, and even if the composition is high in nitrogen-based compounds, there still is produced considerable carbon and other solid combustion residue 104, which is captured in the defined contained area inside the internal cup shape of broken-off casing 50 as shown in FIG. 7. The casing 50 remaining in the launcher barrel breech 122 provides the means to contain and hold the burnt, expelled gunpowder residue 104 of each projectile round, thereby keeping the barrel 120 chamber relatively clean and greatly extending the duty/cleaning cycle of the launcher.

(29) As an alternative to the ETRONX primer and propellant system described above, a gel-type explosive may be employed, which combines the primer and main charge of the propellant. In such case, as shown in FIG. 2, the primer may be eliminated, the electrode may be surrounded by annular insulator 114, and the electrode end 112 in combustion chamber 100 may be extended into a gel-type propellant itself to ignite the propellant 101.

(30) In a further modification shown in FIG. 10, an electrically non-conductive layer 115 (see also FIGS. 11 and 12) is disposed between the gel-type propellant 101 and the upper end of combustion chamber 100 opposite upper end 94 of piston 90, and has a central opening 116 for receiving electrode end 112. Electrically non-conductive layer 115 may be made of a polymer with a thickness of approximately 0.15 in. (0.4 mm) and may form a layer within combustion chamber 100 extending up to the entire width of combustion chamber 100, and may further extend 117 in a cup shape (FIGS. 11 and 12) along the side walls of combustion chamber 100. An electrically conductive layer 118 is disposed adjacent electrically non-conductive layer 115 and may similarly extend up to the entire width of the combustion chamber to form a layer between the electrically non-conductive layer and the gel-type propellant 101. Electrically conductive layer 118, shown in the form of a metal disk or plate of stainless steel or aluminum of approximately 0.3 in. (0.8 mm) thickness (FIGS. 13 and 14), may have a stamped or otherwise formed projection 119 extending from the center of the surface opposite the propellant to facilitate good electrical contact with end 112 of electrode 110. Electrically non-conductive layer 115 and side walls 117 form an insulative liner to ensure that the igniting electrical current is transferred directly to the gel-type propellant 101 and not dissipated into the metal walls of the upper portion of inner sleeve 80 surrounding the combustion chamber 100. Electrically conductive layer or plate 118 ensures that the igniting electrical current is transferred uniformly along the end of the gel-type propellant within the upper end of the combustion chamber and further acts as a pressure-directing shutoff, to ensure that the force of the ignited combustion products is in the direction of piston 90.

(31) The gel-type explosive provides an improvement over gunpowder-type primer and propellant systems because the pressure vs. time curve is flatter. For low velocity projectiles, the ignition thrusts the projectile into the rifling of the barrel with a slower, more uniform combustion rate. As a result of the elimination of the ETRONX primer ignition and the direct contact of the electrode 110 or the electrically conductive disk 118 with the gel propellant 101, the energy is transferred more rapidly to the piston, thereby increasing efficiency of the piston propulsion stage and increased velocity with less propellant. Additionally, the combustion byproducts are water vapor, hydrogen and reduced solids, so that less residue remains in the barrel and weapon duty cycles is increased.

(32) The domed ogive of projectile 40 shown may be further modified in accordance with the intended use of the projectile. While the projectile shown in FIGS. 1-14 may be employed as a non-lethal projectile with the blunt trauma ogive 62 and body 60, further modifications may include the additions of a die marker round, as shown in FIGS. 15 and 16. Ogive 62′ of projectile 40′ may house, for example, a ⅜ in. diameter rupture capsule 140 that can hold various marker/paint formulation, as shown in FIG. 16 in cross-section. As best shown in FIG. 15, the nose 62′ cover may also be pre-molded with tear joints 142 extending from the tip of the nose down a portion of the side, to aid in opening of capsule 140 upon contact with the intended target. In some embodiments, the die marker nose 62′ may have a smaller diameter than that of the body 60′ so that the rifling of the launcher barrel does not disturb the perforations 142 during loading and firing of round 40′. The die marker round 40′ has the same headspace as the blunt trauma jacket 40, thus permitting interchangeability of rounds 40,40′ within a single launching system. The different use body jackets 60, 60′ may be configured to fit over a common combustion assembly of upper inner sleeve 80, lower inner sleeve 70 and the combustion chamber 100 and piston 90 therein, and to connect the lower end to a common casing 50. Additionally, other variant body jackets 60, 60′ may include a sticky chip that will have some electronics with an adhesive to stick to a target, to monitor location thereof.

(33) The casing may be headstamped with identifying information such as caliber, round type, manufacturing date and/or other data. The casing also hermetically seals the projectile round from air or water invasive contamination, thus extending the shelf life significantly.

(34) Upon activation of a bolt handle, slide, charging handle, or other similar device known in the art, the casing may be extracted at the end of the bolt stroke via a knockout rod and extractor system engaging casing extractor groove 58. Casing groove 58 or another extractor groove molded or formed into the projectile body or jacket 60 may be used to enable mechanical means to eject a live cartridge that has malfunctioned.

(35) The present invention advantageously reduces and/or significantly eliminates fouling residue on a bolt face electrode inside the barrel chamber. The present invention provides the advantage of a method and apparatus that may be used with an electrically energized two stage piston/rocket projectile that captures the majority of the ignition debris and further may be readily evacuated with each round, thereby leaving the chamber with little to no propellant residue. This method and apparatus increases the duty cycle and fired projectile round count before operational field cleaning is needed. In addition, clue to the larger diameter of shearing between the base cap and projectile joint, the present invention offers a more accurate release of the projectile within the launching system.

(36) While the present invention has been particularly described, in conjunction with one or more specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.