Abstract:
A multi-stage fragmenting projectile has a number of grooves and slots that are strategically placed on and around the periphery of the projectile. After the projectile engages an object, a first set of fragments separates from a main body of the projectile. A second set of fragments separate a short time later after the projectile has traveled farther in the object.

Description:
REFERENCE TO RELATED CASE 
     This application claims priority under 35 U.S.C. §119(e) to provisional application No. 61/980,968, filed on Apr. 17, 2014, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     Projectiles typically are of relatively small diameter and thus create a small opening in an object into which they are projected or fired. While the diameter of the projectile may be increased and openings in the nose of the projectile allow for the projectile to create a larger opening and a larger void in the object, respectively, the openings are still sometimes insufficient for the purposes needed. Other projectiles have been manufactured to allow for some fragmentation, but that fragmentation occurs only once and typically right after entry. Multiple stages of fragmentation would provide for a larger void within the object. 
     Thus, a new fragmenting projectile has multi-stage fragmentation, providing a first stage of fragmentation of the projectile or bullet followed shortly thereafter with a second stage of fragmentation. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a fragmenting projectile that includes a main body having a front end, a back end, and a middle portion therebetween, the main body having a longitudinal axis extending therealong, an opening extending from the front end toward the middle portion, the opening having a bottom, at least two circumferential grooves extending around the main body, a first circumferential groove disposed between the front end and a second circumferential groove, the second circumferential groove being disposed between the first groove and the bottom of the opening, a first plurality of slots disposed around the main body and extending from the front end rearwardly towards the back end and the first circumferential groove, and a second plurality of slots disposed around the main body, the second plurality extending between the first and second circumferential groves. 
     In some embodiments, one of the first plurality of slots is at least partially disposed between two of the second plurality of slots. 
     In other embodiments, the first and second plurality of slots extend at least partially around the main body. 
     In yet other embodiments, the first and second plurality of slots have a constant depth. 
     The present invention is also directed to a fragmenting projectile that includes a main body having a front end, a back end, and a middle portion therebetween, the main body having a longitudinal axis extending therealong, an opening extending from the front end toward the middle portion, the opening having a bottom, a first means for fragmenting at least a portion of the projectile in a first stage after engaging an object, and a second means for fragmenting at least a portion of the projectile in a second stage after engaging the object, the second stage coming after the first stage. 
     In some embodiments, the first means comprises a first circumferential groove and a first plurality of slots extending from the front end of the main body to the first circumferential groove and the second means comprises a second circumferential groove disposed between the first circumferential groove and the back end and a second plurality of slots extending from the first circumferential groove to the second circumferential groove. 
     Additional features and advantages of the invention will be set forth in the detailed description which follows and, in part, will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description, the claims, and the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a fragmenting projectile according to the present invention; 
         FIG. 2  is a cross section view of the fragmenting projectile in  FIG. 1  along the line  2 - 2 ; 
         FIG. 3  is cross section view of the fragmenting projectile in  FIG. 1  along the line  3 - 3 ; 
         FIG. 4  is a perspective view of a cross section of the fragmenting projectile of  FIG. 3  schematically illustrating the first stage of fragmentation; 
         FIG. 5  is a perspective view of a cross section of the fragmenting projectile of  FIG. 2  schematically illustrating the second stage of fragmentation; 
         FIG. 6  is a perspective view of a second embodiment of a fragmenting projectile according to the present invention; 
         FIG. 7  is a perspective view of the fragmenting projectile in  FIG. 6  schematically showing the fragmentation of the projectile as it travels through an object, the object being removed to show approximate paths of the fragments; 
         FIG. 8  is a perspective view of a third embodiment of a fragmenting projectile according to the present invention 
         FIG. 9  is a perspective view of a fourth embodiment of a fragmenting projectile according to the present invention; 
         FIG. 10  is a perspective view of a fifth embodiment of a fragmenting projectile according to the present invention; 
         FIG. 11  is a cross section view of the fragmenting projectile in  FIG. 10  along the line  11 - 11 ; and 
         FIG. 12  is a cross section view of another embodiment of a fragmenting projectile showing a slot with a flat bottom surface. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     One embodiment of a fragmenting projectile  100  is illustrated in  FIGS. 1-5 . The fragmenting projectile  100  has a main body  102  having a front end  104 , a back end  106 , and a middle portion  108  therebetween. The main body  102  has a longitudinal axis A extending therealong. See  FIG. 2 . The main body  102  also has an opening  110  extending from the front end  104  toward the middle portion  108 , the opening  110  having a bottom  112 . See  FIGS. 2-5 . The main body  102  is preferably made of a dense material such as copper, lead or other alloy, but any appropriate material may be used and still fall within the scope of the present invention. Additionally, given the number of different combinations of diameters of the fragmenting projectile  100  and the differences in weights, it should realized that the specific shape of the projectile  100  may be changed and fall within the scope of the present invention as well. 
     The main body  102  also includes at least two circumferential grooves extending around the main body  102 . A first circumferential groove  120  is disposed between the front end  104  and a second circumferential groove  122 . The first and second circumferential grooves  120 , 122  extend from an outer surface  114  of the main body  102  toward the opening  100 , which has an axis that coincides with the longitudinal axis A of the main body  102 . The second circumferential groove  122  being disposed between the first groove and the back end  106  of the main body  102 . The second circumferential groove  122  may also be more preferably disposed between the first circumferential groove  120  and the bottom  112  of the opening  110 . 
     The main body  102  also includes a first plurality of slots  130  disposed around the main body  102  and extending from the front end  104  rearwardly towards the back end  106  and the first circumferential groove  120 . As illustrated in  FIGS. 1-5 , there are two slots  130  in the first plurality of slots in the first embodiment of the fragmenting projectile  100 . See in particular  FIG. 2 . As described in more detail below, there can be additional slots in the plurality of slots, e.g., three or four in each of the plurality of slots. See  FIGS. 6 &amp; 8 . There is also a second plurality of slots  132  disposed around the main body  102 , the second plurality of slots  132  extending between the first and second circumferential groves  120 , 122 . See in particular  FIG. 3 . As illustrated in  FIG. 1 , the first plurality of slots  130  extend between the front end  104  and at least the first circumferential groove  120 , and the second plurality of slots  132  extend between at least the first and second circumferential grooves  120 , 122 . The reason for these positionings will become more clear in the discussion related to  FIGS. 4 and 5  below. 
     As the fragmenting projectile  100  enters an object (not illustrated for clarity), the opening  110  in combination with the first plurality of slots  130  and the first circumferential groove  120  allow the front portion  140  of the fragmenting projectile  100  to be detached from the main body  102  after interacting with the object in two pieces. See  FIG. 4 . As the fragmenting projectile  100  travels farther into the object, and with the front portion  140  of the fragmenting projectile  100  now detached, the second portion  150  of the fragmenting projectile  100  engage the object and two more pieces detach as well. See  FIG. 5 . 
     As illustrated, the first and second plurality of slots  130 ,  132  have a generally circular shape, with the bottom surface  134  of the slots being curved relative to the longitudinal axis A. Also, given the shape of the outer surface  114  of the main body  102 , and the need to have at least a portion of the main body disposed between the first and second plurality of slots  130 ,  132  and the opening  110 , the first and second plurality of slots  130 ,  132  have a variable depth. However, the first and second plurality of slots  130 ,  132  may also be made so that the depth thereof is constant. See, e.g, slots  532  in  FIG. 11 . 
     Another embodiment of a fragmenting projectile  200  is illustrated in  FIGS. 6 and 7 . Fragmenting projectile  200  has a main body  202  having a front end  204 , a back end  206 , and a middle portion  208  therebetween. The main body  202  also has an opening  210  extending from the front end  204  toward the middle portion  208 , the opening  210  also having a bottom (not shown). 
     The main body  202  also includes two circumferential grooves extending around the main body  202 . A first circumferential groove  220  is disposed between the front end  204  and a second circumferential groove  222 . The first and second circumferential grooves  220 , 222  extend from an outer surface  214  of the main body  202  toward the opening  200 . The second circumferential groove  222  being disposed between the first groove and the back end  206  of the main body  202 . The second circumferential groove  222  may also be more preferably disposed between the first circumferential groove  220  and the bottom  212  of the opening  210 . 
     The main body  202  also includes a first plurality of slots  230  disposed around the main body  202  and extending from the front end  204  rearwardly towards the back end  206  and the first circumferential groove  220 . As illustrated in  FIG. 6 , there are now three slots  230  in the first plurality of slots in the first embodiment of the fragmenting projectile  200 . There is also a second plurality of slots  232  disposed around the main body  202 , the second plurality of slots  232  extending between the first and second circumferential groves  220 , 222 . There are three slots in the second plurality of slots  232 . 
       FIG. 7  illustrates in a three dimensional representation how the first and the second portions detach after entering the object (not shown). The front portion  240  of the fragmenting projectile  200  detaches first (three pieces in the first portion with the three slots  230 ), and then the second portion  250  of the fragmenting projectile  200  engages the object and three more pieces detach as well, leaving only a portion of the main body  202 ′. 
     Another fragmenting projectile  300  is illustrated in  FIG. 8 . In this embodiment, the fragmenting projectile  300  has the same number of circumferential grooves extending around the main body  302 . A first circumferential groove  320  is disposed behind the front end  304  and also has a more rearward second circumferential groove  322 . The circumferential grooves  320 ,  322  determine the number of stages of fragmentation. The fragmenting projectile  300  also has a first and second plurality of slots  330 , 332 , which number four in this embodiment. As can be recognized, it is preferable that the plurality of slots in the embodiments are equally distributed around the periphery of the projectiles. However, provided that the projectiles could be otherwised balanced for rotation, the plurality of slots could be spaced in other ways. Fragmentation of the fragmenting projectile  300  leads to four pieces in the first and second stages, referring to  FIG. 7   
     Another fragmenting projectile  400  is illustrated in  FIG. 9 . The main body  402  of the fragmenting projectile  400  may be the same as those described above. However, in this embodiment, the first and second plurality of slots  430 , 432  extend at least partially around the main body  402 . Thus, the first and second plurality of slots  430 , 432  are more helical, rather than the linear slots noted above. While only two slots are illustrated in each of the plurality of slots  430 , 432 , there could be three, four or even more and still fall within the scope of the present invention. 
     Another fragmenting projectile  500  is illustrated in  FIGS. 10 and 11 . The main body  502  of the fragmenting projectile  500  may be the same as those described above. However, in this embodiment, the first and second plurality of slots  530 , 532  extend along the length of the main body  502  differently. Looking at  FIG. 11 , the first plurality of slots  530  extend only between the front end  504  and the first circumferential groove  520 . The second plurality of slots  532  extend only between the first and the second circumferential grooves  520 , 522 . In this embodiment, the slots do not cross over the circumferential grooves. It should be noted that while two grooves are illustrated for each of the first and second plurality of slots  530 , 532 , there may more slots in either or each of the plurality of slots and still fall within the scope of the present invention. 
     Another fragmenting projectile  500 ′ is illustrated in  FIG. 12 . The main body  502 ′ of the fragmenting projectile  500 ′ is the same as in  FIGS. 10 and 11 , with a the plurality of slots  530 ′, 532 ′ and first and the second circumferential grooves  520 ′, 522 ′. However, the bottom surface  534 ′ of the plurality of slots  530 ′, 532 ′ is flat along at least a portion thereof. The bottom of the other embodiments may also be flat along at least a portion thereof, even if they are slanted relative to the longitudinal axis of the projectiles. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.