Patent Publication Number: US-7905178-B2

Title: Methods and apparatus for selectable velocity projectile system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains generally to methods and apparatus relating to propulsion systems. 
     2. Description of Related Art 
     Propelling systems find uses in a variety of applications, such as building tools, internal combustion engines, rockets used to launch satellites, missiles, or the like, and ammunition for weapons. Propelling systems have many different types of launch mechanisms. For example, conventional ammunition ignites volatile powders or pellets to produce expanding gases to propel the projectile. The projectile&#39;s velocity depends primarily on the type and amount of propellant used. In systems using cartridges having a cartridge, projectile, and propellant, such as cannon or small arms, the velocity of the projectile is fixed. 
     BRIEF SUMMARY OF THE INVENTION 
     Methods and apparatus according to various aspects of the present invention comprise a propelling system for propelling projectiles with selectable velocity. In one embodiment, the propelling system comprises a cartridge, a propelling system, and a projectile. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the figures, wherein like reference numbers refer to similar elements throughout the figures, and: 
         FIG. 1  is a diagram of an exemplary cartridge. 
         FIGS. 2 and 3  are cross-section diagrams of exemplary cartridges. 
         FIGS. 4 and 5  are diagrams of an exemplary cartridge having two chambers. 
         FIG. 6  is a diagram of an exemplary control system. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The present specification and accompanying drawings show an exemplary embodiment by way of illustration and best mode. While these exemplary embodiments are described, other embodiments may be realized, and logical and mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the detailed description is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the methods or process descriptions may be executed in any suitable order and are not limited to the order presented. Further, conventional mechanical aspects and components of the individual operating components of the systems may not be described in detail. The representations of the various components are intended to represent exemplary functional relationships, positional relationships, and/or physical couplings between the various elements. Many alternative or additional functional relationships, physical relationships, or physical connections may be present in a practical system. 
     The present invention is described partly in terms of functional components and various methods. Such functional components may be realized by any number of components configured to perform the specified functions and achieve the various results. For example, the present invention may employ various materials, explosives, projectiles, propellants, ignition systems, shapes, sizes, and weights for various components, electronic components, mechanical components, and the like, which may carry out a variety of functions. 
     Various aspects of the present invention may be embodied as a customization of an existing system, an add-on product, or a distributed system. Software may be associated with the invention to perform functions such as, for example, timing and control. Accordingly, various aspects of the present invention may take the form of an embodiment combining aspects of both software and hardware. Furthermore, any program or other control functions associated with the present invention, such as for firing and/or controlling the system, may take the form of a computer program executed on any suitable computer, a program executed by dedicated hardware where the program may be stored on any type of medium such as a hard disk, optical storage, and/or the like, or a program embedded in hardware by way of memory or logic. In addition, the present invention may be practiced in conjunction with any number of applications and environments, and the systems described are merely exemplary applications of the invention. Further, the present invention may employ any number of conventional techniques for manufacture, ignition, deployment, and the like. 
     Methods and apparatus according to various aspects of the present invention comprise a munition or other projectile system having a propelling system. The propelling system may be used for any suitable purpose or combination of purposes, such as to move pistons in an internal combustion engine, propel nails from building construction tools, launch satellites into orbit, propel projectiles from weapon systems, or any other suitable application. The methods and apparatus may be adapted for any system propelling and/or moving an object for any purpose. 
     For example, a propelling system according to various aspects of the present invention may be part of a cartridge for a weapon system. In one embodiment, the cartridge comprises a cartridge case, a propelling system, and a projectile attached to the cartridge case. The cartridge may be configured to fire a guided projectile that may require some time between launch and acquiring a desired target. In a system where the muzzle velocity is substantially fixed, the guided projectile launched at a nearby target may pass the desired target before acquiring it, thus decreasing the effectiveness of the guided projectile for targets closer than a certain minimum distance. Accordingly, the propelling system may allow launching a projectile at a variety of launch velocities to enable the guided projectile to be slower and to acquire nearer targets. 
     In particular, referring to  FIGS. 1 and 2 , a cartridge  100  according to various aspects of the present invention comprises a projectile  110 , a cartridge case  112 , and a propelling system  114 . The projectile  110  is positioned at one end of the cartridge case  112 , forming an interior enclosure within the cartridge case  112 . When the propelling system  114  is activated, the propelling system  114  rapidly expands and pushes the projectile  110  away from the cartridge case  112 . 
     The projectile  110  may comprise any appropriate component to be fired from the cartridge case  112 , and may be of any type, shape, and material for a particular application or environment. For example, the projectile  110  may be guided or unguided, may be ballistically or aerodynamically shaped, and may comprise any material suitable for the purpose of the projectile, for example, lead, steel, titanium, plastic, rubber, Teflon, or any combination of materials. The projectile  110  may be guided in any manner, for example, by barrel rifling, barrel aim, wire control, and/or autonomous guiding apparatus. In an exemplary embodiment, the projectile  110  comprises an autonomous guided projectile, made primarily from metal, weighing between 40 and 50 pounds and configured to be launched through a gun barrel. The projectile  110  may have fins  144  ( FIG. 4 ), to aid accuracy of flight and provide flight control surfaces. The projectile  110  may be similar in shape, size, and weight to projectiles used in conventional fixed ammunition weapon systems, such as cannon and small arms. 
     The cartridge case  112  may comprise any suitable system for holding the propelling system  114  and/or the projectile  110  in position. The cartridge case  112  may be of any type, shape, and material appropriate for the particular environment or application. The cartridge case  112  may fasten securely to the projectile  110  until launch, and may be single-use or reloadable. The exterior of the cartridge case  112  may be similar in shape, size, and materials to conventional fixed ammunitions for use in conventional weapon systems, such as conventional cannon and small arms. In one embodiment, the cartridge case  112  holds the projectile  110  in an immobile, non-adjustable position until the projectile is launched, such that the cartridge case  112  and the exposed part of the projectile  110  (if any) form a single integrated unit for pre-launch handling. 
     The propelling system  114  may be configured in any suitable manner to project the projectile  110 . The propelling system  114  may be of any type and may be activated in any suitable manner. The propelling system  114  may also be positioned in any location with respect to the cartridge case  112  and the projectile  110 . In the present exemplary embodiment, the propelling system  114  is largely inside the cartridge case  112 . In an alternative embodiment, the propelling system  114  may be located external to the cartridge case  112  and the cartridge case  112  functions as a conduit between the propelling system  114  and the projectile  110 . 
     Referring to  FIG. 3 , the propelling system  114  of the present embodiment is configured to provide a selectable launch velocity for the projectile  110  by providing multiple propellants or zones of propellants that may be individually activated to propel the projectile. For example, the propelling system  114  may comprise multiple chambers  116  within the cartridge case  112 , each containing a propellant  118 , and an activation system  120 . The chambers  116  divide and separate the propellant  118  into separately ignitable increments of propulsion power, such that the launch velocity of the projectile  110  is controlled by the number of chambers of propellant that may be substantially simultaneously ignited. Igniting a single chamber  116  launches the projectile  110  at minimum velocity. Igniting all chambers  116  substantially simultaneously launches the projectile  110  at maximum velocity. Igniting more than one chamber  116 , but less than the maximum number of chambers  116  propels the projectile  110  at a launch velocity greater than the minimum velocity and less than the maximum velocity. 
     The physical arrangement of the chambers  116  may be selected according to any suitable criteria. Any number of chambers  116  may be partially or fully enclosed within a larger chamber  116 . Additionally, any number of chambers  116  may be enclosed in a nested fashion where a smaller chamber  116  is enclosed in a larger chamber, which in turn is enclosed by an even larger chamber, and so forth. For example, referring to  FIG. 4 , in one embodiment, chamber  122  is placed at least partially inside chamber  124 , such that the smaller chamber  122  is partially enclosed within the larger chamber  124 . Referring again to  FIG. 3 , the chambers  116  may also be placed adjacent to and/or nearby other chambers  116 . For example, one chamber  116  may have multiple chambers around its circumference, or chambers  116  may be layered adjacent to each other. Each chamber  116  may be of any appropriate volume, and various chambers  116  may have substantially equivalent volumes. The volume of each chamber  116  may be selected according to any relevant criteria, such as the volume available for a propelling system  114  in the cartridge case  112 , the placement of each chamber, or controlling the ignition of the propellant  118  in the chambers  116 . 
     One or more chambers  116  contain the propellant  118 . The propellant  118  may comprise any suitable material for driving the projectile, such as explosive or combustible substances. The quantity of propellant  118  in each chamber  116  may be related to the volume of each chamber  116 . For example, referring to  FIG. 5 , a rear chamber  122  is fully loaded with propellant  126 , but the rear chamber  122  may not hold as much propellant  128  as a fully loaded larger forward chamber  124 . Each chamber  116  may hold the same or different amount and/or type of propellant  118 . Therefore, the propellant  118  type may be selected to enable each chamber  116 , regardless of size, to produce substantially equivalent propelling force or other desired propelling force upon ignition. 
     For example, referring again to  FIG. 5 , the rear propellant  126  of the rear chamber  122  may have greater explosive power than the forward propellant  128  of the forward chamber  124 , such that the propelling force provided by igniting the rear propellant  126  is greater than or equal to the propelling force provided by igniting the forward propellant  128 , even though the rear chamber  122  may be smaller in volume than the forward chamber  124 . Additionally, any suitable mixture of propellant  118  may be placed in any chamber  116  to provide a desired propelling force at ignition. 
     The number of possible launch velocities may correspond to the number of propellant  118  zones. A greater number of independently ignitable zones may provide a wider selection of launch velocities. The composition of the propellant  118  in the propelling system may also contribute to a variety of selectable launch velocities. For example, chambers  116  of smaller size may have propellant  118  that is proportionally stronger in firepower, such that a larger chamber  116  may have substantially equivalent firepower as a smaller chamber  116 . Each chamber  116  may propel the projectile with substantially the same amount of force, creating a substantially linear relationship between the number of chambers  116  fired and the launch velocity. Additionally, chamber construction may provide additional variables to select launch velocity. For example, some chambers  116  may be constructed to remain intact until the propellant  118  ignited inside the chamber  116  attains greater pressure, thus enabling some chambers  116  to provide greater propelling power than others and a greater variety of launch velocities when used in combination. 
     Referring to  FIG. 5 , the present exemplary propelling system  114  includes two chambers  122 ,  124 . At least one of the chambers  122 ,  124  contains a propellant  126 ,  128  that may be ignited without igniting the propellant in the other chamber. To generate a high projectile  110  velocity, the propellants  126 ,  128  in both chambers  122 ,  124  are ignited substantially simultaneously. For a lower velocity, only the forward propellant  128  in the forward chamber  124  is ignited. 
     The activation system  120  controls the activation of the propellant  118  in the chambers  116 . The activation system  120  may control the activation of the propellant in the chambers  116  in any way, and may ignite the various chambers  116  according to any appropriate process and/or sequence. For example, the activation system  120  may comprise, referring to  FIG. 3 , one or more igniters  130  and a control system  132 . The igniters  130  ignite the propellant  118  in the chambers  116 , and the control system  132  controls the activation of the igniters  130 . 
     In an exemplary embodiment, each chamber  116  has at least one igniter  130 , though a chamber  116  may not have an igniter  130  if the propellant  118  in the chamber  116  is configured to react to another stimulus, such as ignition of propellant  118  an adjacent chamber  116 . For example, referring to  FIG. 5 , the forward chamber  124  may be positioned such that the pressure and heat caused by igniting the rear propellant  126  in the rear chamber  122  using a rear igniter  134  causes the forward propellant  128  in the forward chamber  124  to ignite without using a forward second igniter  136 . Any method may be used to ignite the propellants  118  in the various chambers  116 , including direct ignition by an igniter  130  directly controlled by the control system  132  or by placement of the chambers  116  such that the ignited propellant  118  ignites propellant  118  in other chambers  116 . 
     The igniters  130  may comprise any suitable device or system for activating the propellant  118 , such as an electrical igniter, a thermal igniter, a concussive igniter, an actuator, or other suitable system. Different types of igniters  130  may be used for different chambers  116  and/or types of propellants  118 . For example, the igniter  130  may comprise a firing cap used in a conventional center-fire ammunition cartridge. Heat and pressure from a firing cap may be used to ignite the propellant  118  in the chamber  116 . The activation system  120  may also include wires, conduits, mechanical connections, and the like through the cartridge case  112  to transport heat, electrical signals, force, pressure, or other suitable trigger signals from a firing cap or other mechanism to a chamber  116  within the cartridge case  112  or enclosed by another chamber  116 . Alternatively, the igniters  130  may activate the propellant  118  and/or be activated by electrical and/or electronic signals. Electrical and/or electronic igniters  130  may be analog or digital by nature and may use any suitable voltage, current, frequency, or other parameter. 
     In the present embodiment, the igniters  134 ,  136  ignite the propellant  118  of the respective chambers  122 ,  124  independently of each other. Igniting the propellant in selected chambers  116  independently of other chambers  116  may allow the projectile  110  to launch at selectable launch speeds. For example, igniting the propellant  126 ,  128  in the rear chamber  122  and forward chamber  124  substantially simultaneously may launch the projectile  110  at a substantially maximum velocity. Igniting the forward propellant  128  of the forward chamber  124  without concurrently igniting the rear propellant  126  in the rear chamber  122  may launch the projectile  110  with a lower velocity. In an exemplary embodiment, igniting only the forward propellant  128  launches the projectile  110  at about 300 meters per second, whereas igniting both propellants  126 ,  128  launches the projectile  110  at 600 meters per second. 
     The control system  132  controls the igniters  130  to selectively activate the propellants  118  in the various chambers  116 . Any type of connector may be used between the control system  132  and the igniter  130 . The control system  132  may control each igniter individually, subsets of igniters, or all igniters simultaneously. Where individual or separate groups of igniters  130  may be controlled, the control system  132  may impose any appropriate timing relationship on the ignition of any igniter  130  and/or group of igniters  130  with respect to any other igniter  130  and/or group of igniters  130 . For example, the control system  132  may impose a wait period between the activation of the various igniters  130 , and the igniters  130  may be activated in any suitable order. 
     In a propelling system  114  where each igniter  130  may be activated exclusive of any other igniter  130 , any method may be used to control the activation of the igniters  130 . For example, the control system  132  may include an activation circuit for generating and/or routing signals to selected igniters  130 . For example, separate, individual wires or other connections may connect the control system  132  to each igniter  130 , and the control system  132  may generate individual signals to selectively activate each igniter  130 . 
     Referring to  FIG. 6 , the control system  132  may comprise a diode steering network  138  comprising first and second diodes  140 ,  142  that directs electrical firing pulses to the igniters  130 . In the present embodiment, a positive pulse applied to the diode steering network  138  activates causes first diode  142  to conduct, causing the electrical signal to be applied to the rear igniter  134  and ignites the rear propellant  126  in the rear chamber  122 . The heat and pressure from the ignited rear propellant  126  in turn ignites the forward propellant  128  in the chamber  124  without using igniter  136 . In another embodiment, the forward and rear propellants  126 ,  128  in the chambers  122 ,  124  may be ignited substantially simultaneously by substantially simultaneously activating the igniters  134 ,  136 . 
     Conversely, a negative firing pulse causes the second diode  140  to conduct and apply the signal to the forward igniter  136 , which in turn ignites the propellant  128  in the forward chamber  124 . The pressure and heat from the forward propellant  128  detonating in the forward chamber  124  do not ignite the rear propellant  126  in the rear chamber  122 . Consequently, the projectile  110  is propelled using the propulsive force of only the propellant  128 . 
     In an exemplary embodiment, firing the variable-speed projectile  110  comprises loading the cartridge  100  into a weapon system, selecting the desired launch velocity, activating the propelling system  114  in a manner to launch a projectile  110  at a desired launch speed, and launching the projectile  110 . The propelling process may further include igniting propellant  118  in all unignited chambers  116  to expend all propellants  118  in the propelling system  114  to increase the safety of handling the spent cartridge  100 , and removing the inert cartridge  100  from the weapon system. 
     Loading the cartridge  100  into a weapon system may be done in any suitable manner. For example, the cartridge  100  may be loaded manually by a single operator or multiple operators, automatically using equipment that requires no human intervention, and/or by a combination of automatic and manual methods. The method of loading ammunition in a weapon system may be combined with the process of unloading a previously fired cartridge case. In the present embodiment, an autoloader places the cartridge  100  into the weapon system. 
     Any available information may be used to determine a suitable launch velocity, and actual selection of the desired launch velocity may be accomplished in any suitable manner. For example, launch velocity may be related to a desired range, proximity of a target, time for a guided projectile to acquire the target, and desire to avoid detection. Once the desired velocity is determined, the velocity may be selected or communicated to the control system  132 , for example by manually setting switches, automatic transfer from range finding equipment, transfer from separate location over a secure or insecure link, and a combination of automatic and manual techniques. 
     The propelling system  114  may be activated in any suitable manner that enables the projectile  110  to be launched at the selected launch velocity. The propelling system  114  may be activated, for example, by pulling a trigger to activate the igniters  130 , waiting for the weapon system to acquire a target and automatically activating the propelling system  114  electronically, and manually activating the control system  132  that electrically activates the propelling system  114 . In the present embodiment, selecting a high velocity causes the control system  132  to generate a positive electric pulse through the second diode  142  and rear igniter  134 , which ignites the rear propellant  126  in the rear chamber  122 . The detonation of the rear propellant  126  in the rear chamber  122  causes the forward propellant  128  in the forward chamber  124  to also detonate, propelling the projectile  110  with the combined force of both propellants  126 ,  128 . The cartridge case  112  is inert after launch because all propellant  118  has been expended. Selecting a low velocity causes the control system  132  to generate a negative electric pulse that routes a signal through the first diode  140  and forward igniter  136 , igniting the forward propellant  128  in the forward chamber  124 . The projectile  110  is propelled with the force generated by forward propellant  128  alone. 
     After the projectile is launched at the desired velocity, propellant  118  remaining in propelling system  114  may be expended to make the cartridge  100  safer to handle. Expending remaining propellant  118  may be accomplished in any suitable manner. For example, the operator or control system  132  may track which chambers  116  were ignited to propel the projectile  110  and ignite the propellant  118  in chambers  116  that were not ignited. Alternatively, the operator or control system  132  may ignite all chambers  116  after the projectile  110  is launched to ensure the propelling system  114  is inert. In the present embodiment, propelling projectile  110  at a low speed leaves the rear propellant  126  intact in the rear chamber  122 . After the projectile  110  is launched and has cleared the weapons system, the control system  132  may generate a positive electric pulse to ignite the rear propellant  126 . The expanding gas generated by detonating propellant  126  exhausts out the barrel of the weapon system. 
     The used cartridge  100  may be unloaded from the weapon system in any suitable manner, for example, either mechanically, manually, or a combination of mechanical and manual activities. The unloading procedure may be, for example, the inverse of the loading procedure. The unloading procedure may be combined with the loading procedure for the next cartridge  100 . In the present embodiment, an autoloader ejects the inert cartridge  100  from the weapon system. 
     Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the exemplary embodiments of this invention. The scope of the present invention fully encompasses other embodiments, and is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described exemplary embodiments are expressly incorporated by reference and are intended, unless otherwise specified, to be encompassed by the claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.” The terms “comprises”, “comprising”, or any other variation, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.