Abstract:
A high velocity ignition system for ammunition including an casing, a primer, a payload, a first propellant region, a flash tube, a second propellant and at least one channel. The casing has a base portion and a forward portion. The primer is provided in the base portion. The payload is provided proximate the forward portion. The first propellant region is located in the casing intermediate the primer and the payload. The flash tube substantially extends between the primer and the first propellant region. The second propellant region is located in the casing intermediate the first propellant region and the base portion. The at least one channel extends between the first propellant region and the second propellant region. A separator with a forward extending cup and a rearward extending cup has a cylindrical portion that engages the inside surface of the casing, spans the internal distance in the casing, and defines flash pathways between the primer and main propellant and between the main propellant and the secondary propellant.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/801,812 filed on Mar. 15, 2013, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention is directed to ammunition. More particularly, the invention is directed to a high velocity ignition system for ammunition. 
     BACKGROUND OF THE INVENTION 
     There are various references directed to the concept of increasing the performance of ammunition such as bullets and shotgun shells. The contents of each of the references discussed herein are incorporated by reference for all purposes. 
     Fibranz, U.S. Pat. No. 4,593,622, describes an industrial cartridge having two propellant sections. A flash tube has a thinner end wall than side wall. As a result of this configuration, the flame passes through the end of the flash tube to ignite the first propellant section. The second propellant charge is adjacent to the first propellant section such that ignition of the first propellant section results in ignition of the second propellant section. 
     Crilly, U.S. Pat. No. 5,880,397, is directed to ammunition having two propellant regions. A first propellant region contains low velocity propellant and is located between the primer and the projectile. A second propellant region contains high velocity propellant and is located around an outer surface of the primer. 
     Dindl, U.S. Pat. No. 7,207,276, discloses non-lethal ammunition having a two-stage firing. The ammunition includes an inner propellant region and an outer propellant region that extends around the inner propellant region. The outer and inner propellant regions are ignited using separate primers. 
     Schluckebier et al., U.S. Pat. No. 8,220,393, is directed to ammunition having two propellant regions. A first propellant region is located along a central axis of the ammunition between the primer and the payload. The second propellant region is located radially outward from the first propellant region such that the second propellant region is between the first propellant region and a casing of the ammunition. 
     Thouin, French Patent No. 78,417, describes ammunition having a first propellant region that is located along a central axis of the ammunition between the primer and the payload. Similar to Schluckebier, which is discussed above, a second propellant region is located radially outward from the first propellant region such that the second propellant region is between the first propellant region and a casing of the ammunition. 
     Chetcuti, Canadian Patent Publication No. 2,173,968, discloses ammunition that is configured to reduce recoil typically associated with shotgun ammunition. The ammunition includes a plurality of toric members mounted to an outer surface of the flash tube. Each of the toric members has an air space therein, which enables the toric members to deflect and thereby absorb the recoil. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention is directed to a high velocity ignition system for ammunition that includes a casing, a primer, a payload, a first propellant region, a flash tube, a second propellant region and at least one channel. 
     The casing has a base portion and a forward portion. The primer is provided in the base portion. The payload is provided proximate the forward portion. The first propellant region is located in the casing intermediate the primer and the payload. 
     The flash tube substantially extends between the primer and the first propellant region. The flash tube may have an extension to extend upwardly near the forward portion of the propellant facilitating a rearward burn. The second propellant region is located in the casing intermediate the first propellant region and the base portion. The at least one channel extends between the first propellant region and the second propellant region. 
     Another embodiment of the invention is directed to a method of increasing velocity of ammunition. A primer is activated to cause a first flame to be emitted therefrom. The first flame is directed through a flash tube towards a first propellant region. The first propellant region is ignited with the first flame. 
     A second flame is directed from the first propellant region to the second propellant region through at least one channel. The second propellant region is in a spaced-apart configuration from the first propellant region. The second propellant region is ignited with the second flame. The payload is propelled away from the casing with a combined force generated by the ignition of the first propellant region and the second propellant region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  is a side view of ammunition that incorporates a high velocity ignition system according to an embodiment of the invention prior to ignition. 
         FIG. 2  is a side view of the ammunition where propellant in a first propellant region has been ignited. 
         FIG. 3  is a side view of the ammunition where the propellant in the first propellant region causes a payload to be pushed out of the ammunition and causes propellant in a second propellant region to be ignited. 
         FIG. 4  is a side view of the ammunition where the ignited propellant in the first propellant region and the second propellant region causes the payload to be pushed out of the ammunition. 
         FIG. 5  is a perspective view of the propellant separator, integral flash tube and wadding. 
         FIG. 6  is a side elevational view of the propellant separator and integral flash tube of  FIG. 5 . 
         FIG. 7  is a top plan view of the propellant separator and integral flash tube of  FIG. 5 . 
         FIG. 8  is a bottom plan view of the propellant separator and integral flash tube of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the invention is directed to ammunition that exhibits enhanced payload velocity when compared to prior art ammunition. The ammunition is identified at  10  in the figures. 
     The prior art ammunition generates a payload velocity that is limited by a maximum pressure rating for the gun system in which the ammunition is intended to be used. The ammunition produced according to this invention is able to achieve a payload velocity that is greater than the prior art by using two propellant chambers, which are ignited in sequence as is discussed in more detail below. 
     The ammunition  10  includes a casing  20 , as illustrated in  FIG. 1 . In certain embodiments, the casing  20  has a generally cylindrical shape and includes a base portion  22  and a forward load exit portion  24 . 
     The casing  20  is formed with a size, a shape and from a material based upon a type of gun system (not shown) in which the ammunition  10  is intended to be used. In certain embodiments, the ammunition  10  is designed for use in small caliber gun systems. In other embodiments, the ammunition  10  is designed for use in a shotgun or a rifle. A principal embodiment is utilized for 12 gauge and 20 gauge shotgun shells. 
     In certain configurations, the base portion or head  22  includes an outwardly extending flange  26  that facilitates retaining the ammunition  10  in a desired position within the gun system during the firing process. A person of skill in the art will appreciate that the outwardly extending flange  26  may have a variety of shapes and sizes depending on the gun system in which the ammunition  10  is intended to be used. The illustrated flange is suitable for shotgun shell applications. 
     The casing  20  may have a generally tubular configuration in which the other components of the ammunition  10  are placed. A primer  30  may be placed in the base portion  22 , along a central axis of the ammunition  10 . A propellant separator and flashtube unit  23  provides a flash tube  34  to directly transfer the flash of the primer to the forward propellant, and further flash pathways  50 , which may be channels or tubes in certain embodiments, extend from the rearward region of the forward propellant chamber to the rearward propellant chamber. Positioned around the primer  30  in the base portion  22  may be a spacer configured as a basewad  32  assembled with the cartridge, or the spacer may be an integral or unitary part of the head of the cartridge. In certain embodiments, the basewad or spacer  32  may have a height that is similar to or equal to a height of the primer  30 . An edge of the basewad  32  that is opposite the base portion  22  may be cupped so that proximate the casing  20 , the basewad  32  has a greater height than proximate the primer  30 . Using such a configuration may cause a force generated by the ignition of the propellant in the first propellant region  40  and the second propellant region  42  to be directed towards the payload  60  to thereby increase a velocity at which the payload  60  is propelled from the gun system. 
     The ammunition  10  includes at least two propellant regions  40 ,  42 , in a forward chamber and a rearward chamber, that are separated from each other to facilitate sequential, that is, staged, igniting of the propellant regions. The first propellant region  40  may contain the primary propellant that is used to initially launch and propel the payload  60 . As such, a volume of the first propellant region  40  may be greater than a volume of the second propellant region  42 . 
     The first propellant region  40  may be located proximate to a lower end of the payload  60  such that the first propellant region  40  and the payload  60  are on opposite sides of a payload cup that may function as a gas obturating wad  44 . 
     A volume of the first propellant region  40  may be selected based upon a variety of factors. Examples of these factors include the type of gun system in which the ammunition  10  is intended to be used, the maximum pressure intended to be generated, and the weight and type of payload. 
     In particular embodiments, there is a distance between the first propellant region  40  and the primer  30 . A flash tube  34  may be provided between the primer  30  and the first propellant region  40 . The flash tube  34  directs a flame that is emitted when the primer  30  is ignited towards the first propellant region  40 . 
     The flash tube  34  thereby prevents the second propellant region  42  from igniting when the first propellant region  40  is ignited. A person of skill in the art will appreciate that a variety of configurations and materials may be used for fabricating the propellant separator and flash tube  34 . As indicated in  FIG. 5 , the flash tube can have an extending portion extend toward the forward portion of the main propellant region facilitating a rearward burn and likely delaying the ignition of the secondary propellant. 
     In certain embodiments, the flash tube  34  has a substantially tubular profile with a diameter that is generally consistent between the primer  30  and the first propellant region  40 . In other embodiments, the flash tube  34  tapers so that a diameter of the flash tube  34  proximate the primer  30  is greater than a diameter of the flash tube  34  proximate the first propellant region  40 . The flash tube is advantageously integral with the structure providing the propellant separation and flash pathways between the main forward propellant and the rearward secondary propellant. 
     The second propellant region  42  may be formed in a donut-shape that extends around at least a portion of the flash tube  34 . Forming the second propellant region  42  to extend around the flash tube  34  enhances the ability to apply an even force to the payload  60  to thereby cause the payload  60  to be propelled in a linear direction. 
     In certain embodiments, the second propellant region  42  substantially fills a region between the first propellant region  40  and the basewad  32  that is outside of the primer  30 . In other embodiments, at least one filler material such as a wad  62  may be provided in this region when it is desired for a smaller volume of the second propellant region  42  to be used. 
     A height of the second propellant region  42  is less than the height of the flash tube  34 . Using such a configuration, there is a separation of the first propellant region  40  and the second propellant region  42 . 
     At least one flash tube channel  50 , defined by structure  51  of the propellant separator and flashtube unit  23 , substantially extends between the first propellant region  40  and the second propellant region  42 . The at least one channel  50  thereby directs flame emitted from the first propellant bed or region  40  to the second propellant bed or region  42  to cause efficient and reproducible ignition of the second propellant bed or region  42 . 
     The at least one channel  50  may thereby be used to control a delay between ignition of the first propellant region  40  and the second propellant region  42  by varying a number and/or a size of the at least one channel  50 . The channels could also be configured as tubes. 
     For example, when the at least one channel  50  is formed with a greater area and/or there are a greater number of the at least one channel  50 , the delay between ignition of the first propellant region  40  and the second propellant region  42  may be decreased. Conversely, decreasing the area of the at least one channel  50  and/or the number of the at least one channel  50  may increase the delay between ignition of the first propellant region  40  and the second propellant region  42 . 
     In certain embodiments there are a plurality of generally cylindrically shaped channels  50  that substantially extend between the first propellant region  40  and the second propellant region  42 . Each of these channels may have a diameter that is less than a thickness of each side of the second propellant region  42 , as illustrated in the figures. 
     In other embodiments, the at least one channel  50  has a cylindrical shape with an inner diameter that is larger than an inner diameter of the second propellant region  42  and an outer diameter that is smaller than an outer diameter of the second propellant region  42 . Using such a configuration, the at least one channel  50  limits the ability of the flames emitted from the first propellant region  40  to reach the second propellant region  42 . 
     The delay between ignition of first propellant region  40  and the second propellant region  42  may be selected to flatten a pressure time curve generated by the ammunition  10 . A factor that may affect the desired delay include the maximum pressure of the gun system. For example, if the delay is too short, the combined pressure exerted by the first propellant region  40  and the second propellant region  42  may exceed the maximum pressure of the gun system. 
     In certain embodiments, the propellant in the first propellant region  40  may be the same as the propellant in the second propellant region  42 . In other embodiments, the propellant in the first propellant region  40  may be formed from a different material than the propellant in the second propellant region  42 . For example, the propellants may be selected to have different combustion rates. An example of one suitable propellant that may be used in the first propellant region  40  and the second propellant region  42  is gun powder. 
     A payload  60  is provided proximate the forward portion  24 . The payload  60  is the portion of the ammunition  10  that is propelled when the first propellant region  40  and the second propellant region  42  are ignited. The payload  60  may assume a variety of forms depending on the type of gun system in which the ammunition is intended to be used. 
     An example of one type of payload  60  is a plurality of shot pellets  62  that are loosely placed within the forward portion  24  when the ammunition is a shotgun shell. Another example of the payload  60  is a slug that is attached to the forward portion  24  when the ammunition is a bullet. 
     In operation, the primer  30  is ignited as illustrated in  FIG. 2 . This ignition causes a flame to be emitted from the primer  30 . This flame passes through the flash tube  32  and into the first propellant region  40  to cause the first propellant region  40  to be ignited. 
     Ignition of the first propellant region  40  causes the payload  60  to be forced out of the casing  20 , as illustrated in  FIG. 3 . Ignition of the first propellant region  40  also causes flames to pass through the at least one channel  50 . 
     The flames passing through the at least one channel  50  then cause the second propellant region  42  to ignite. This process causes the wadding and the payload  60  to be accelerated forward out of the gun system. 
     As noted above, the configuration of the ammunition  10  causes a delay between the ignition of the first propellant region  40  and the second propellant region  42 . This delay in ignition increases the pressure behind the payload  60  without the combined pressure from the first propellant region  40  and the second propellant region exceeding the maximum pressure of the gun system. This process thereby increases the velocity of the payload  60  as the payload exits the gun system. 
     In the preceding detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The preceding detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
     It is contemplated that features disclosed in this application, as well as those described in the above applications incorporated by reference, can be mixed and matched to suit particular circumstances. Various other modifications and changes will be apparent to those of ordinary skill.