Abstract:
A top cover and safing blade assembly replaces the prior art top cover and safing sector in 7.62 miniguns. The top cover and aft camming portion of a longitudinal helical track are combined in a single unit, thus permitting the forward camming portion of the helical track, incorporated in the safing blade, to be removed separately. Safing the gun by opening the safing blade and rearming it by closing the safing blade can be accomplished in far less time than is required in prior art safing systems. Live cartridges can be quickly cleared from the minigun by electrically rotating the barrels after the safing blade has been locked in its open position.

Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    This application is related to the subject matter of U.S. patent application Ser. No. 11/585,529 entitled MACHINE GUN filed on Oct. 24, 2006, by the same inventor. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    This invention relates generally to automatic weapons of the Gaffing machine gun type and, more specifically, to the class of such guns known as 7.62 miniguns and improvements therein that serve to make them easier to use by incorporating a safing blade mechanism in the top cover of such guns. 
         [0003]    The 7.62 minigun is a six-barreled, electrically-driven machine gun originally designed and built by General Electric Company in the mid 1960&#39;s for the U.S. military. This gun has been in use since its inception by both U.S. and foreign military forces. 
         [0004]    The 7.62 minigun, hereinafter referred to as either a minigun or machine gun, utilizes a main housing enclosing and supporting a main rotary body known as a rotor assembly. Cartridges, each of which represents a single round of ammunition, are handled within the main housing by bolt assemblies. The minigun includes six bolt assemblies, one associated with each of the six barrels. The six bolt assemblies are attached to and surround the rotor assembly. The rotor assembly comprises the core axis of the minigun. The six barrels are attached to the forward portion of the rotor assembly and are arranged for rotation as a cluster around the core axis of the minigun. As the rotor rotates, the bolt assemblies are driven forward and rearward by a helical track incorporated within the main housing which, in turn, causes cartridges to be delivered to the bolt assemblies, chambered, and fired. The empty cartridges are extracted from the chambers and ejected. The rotor is rotated by means of a series of gears driven by an electric motor. 
         [0005]      FIGS. 1-4  depict a basic prior art top cover and safing sector assembly. The top cover and safing sector assembly is externally attached to the main housing of a minigun. The safing sector forms a portion of the helical track used to drive the minigun bolt assemblies forward and rearward. The top cover is attached to the safing sector by means of a semi-permanent retaining pin that allows the top cover to pivot independently of the safing sector. The pivot feature between the top cover and the safing sector allows the top cover to be opened and closed independently of the safing sector. The top cover opens like a hatch to allow the operator of the minigun quick access to the inner workings thereof. After the top cover has been opened, the safing sector can be either partially or completely removed from the minigun. The purpose of partially removing the safing sector is to dislocate the critical section of the helical track that causes the bolt assemblies to fire the cartridges. After the safing sector has been partially or completely removed, the minigun cannot be fired, hence the term “safing sector.” Disabling the minigun so that it cannot fire is hereinafter referred to as safing the gun. Since their inception, all 7.62 miniguns have employed top covers and safing sectors of the same basic design. 
         [0006]    There are essentially two situations in which it is desirable to safe the gun. The most common is when the minigun is loaded with live cartridges and is not in use. The second situation is when a jam occurs during use of the minigun, causing it to stop firing. In order to safe the gun in either of these situations, a conventional top cover and safing sector system requires the operator to first open the top cover to facilitate removal of the safing sector from its firing position. In a combat or training environment, safing the gun by removing both the top cover and safing sector is a time consuming and physical inconvenience. 
         [0007]    Furthermore, when a jam occurs, the operator may be required to remove live cartridges from the rotor assembly without firing them. Doing so requires rotation of the barrels of the minigun. In order to cycle live cartridges through the minigun without firing them, the top cover and safing sector must be removed prior to rotating the barrels. Following removal of the top cover and safing sector, the barrels can be rotated manually, but not electrically. If the barrels are inadvertently rotated electrically with the safing sector in its partially or completely open position, the bolt assemblies will be damaged and the minigun will become inoperable. The barrels can only be rotated electrically when the safing sector is in its closed and firing position. 
         [0008]    The prior art top cover and safing sector assembly described above and illustrated in  FIGS. 1-4  is disadvantageous in that safing the gun requires opening of the top cover and removal of the safing sector. Simply opening the top cover does not provide improved safety or functionality. In addition, manual rotation of the hot barrels following recent use of the gun is difficult. Thus, safing a prior art minigun is at the very least inconvenient when attempting to do so in combat or training environments. 
         [0009]    It would therefore be advantageous to provide a replacement for top cover and safing sectors of the prior art that will enable an operator to safe a minigun without opening the top cover and to rotate the barrels electrically after the minigun has been safed. 
         [0010]    In accordance with the illustrated preferred embodiment of the present invention, a one-piece top cover and safing blade assembly replaces the prior art two-piece top cover and safing sector. The top cover and safing blade assembly is arranged to be mounted using existing locating features within the main housing of the minigun, thereby facilitating its ready adaptation to existing miniguns. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a pictorial diagram of a prior art machine gun top cover and safing sector assembly installed on a machine gun main housing. 
           [0012]      FIG. 2  is a pictorial diagram of the prior art top cover and safing sector assembly of  FIG. 1 , illustrating the top cover in its open position. 
           [0013]      FIG. 3  is a pictorial diagram of the prior art top cover and sating sector assembly of  FIG. 1 , illustrating both the top cover and the safing sector in their open positions. 
           [0014]      FIG. 4  is a pictorial diagram of the underside of the prior art top cover and safing sector assembly of  FIG. 1 , removed from the minigun main housing. 
           [0015]      FIG. 5  is a pictorial diagram of a machine gun top cover and safing blade assembly constructed in accordance with the present invention. 
           [0016]      FIG. 6  is an assembly diagram of the top cover and safing blade assembly of  FIG. 5 . 
           [0017]      FIG. 7  is a pictorial diagram of the machine gun top cover and safing blade assembly of  FIGS. 5 and 6 , illustrating its installation on a machine gun main housing. 
           [0018]      FIG. 8  is a pictorial diagram of the machine gun top cover and safing blade assembly of  FIGS. 5 and 6 , installed on a machine gun housing, as in  FIG. 7 , illustrating the safing blade in its open position. 
           [0019]      FIG. 9  is a pictorial diagram of the machine gun top cover and safing blade assembly of  FIGS. 5-8 , illustrating the locking mechanism that retains the safing blade in its open position. 
           [0020]      FIG. 10  is a pictorial diagram of the underside of the machine gun top cover and safing blade assembly of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring generally to  FIGS. 1-4 , there is shown a prior art top cover  30  and safing sector  31  and the way in which they are hingedly connected adjacent each other and to a main housing  8  of a conventional minigun. As illustrated in  FIGS. 3 and 4 , a helical track  20  is provided in sating sector  31 . Helical track  20  extends longitudinally within main housing  8 . Conventional bolt assemblies include a roller bearing that rides in helical track  20 . As the barrels of the minigun rotate, the bolt assemblies enter helical track  20  at location  23  of  FIG. 4  and exit helical track  20  at location  24 . Helical track  20  includes forward and aft camming portions  21 ,  22 , respectively. Camming portions  21 ,  22  of helical track  20  are both bearing surfaces that force the bolt assemblies in forward and aft directions, respectively. A straight section of helical track  20 , illustrated by sidewalls  25  of  FIG. 4 , serves as a guide between forward and aft camming portions  21 ,  22  and does not produce a camming action. As the bolt assemblies enter helical track  20  at location  23  and are forced forward by forward camming portion  21  thereof, the firing pin of each bolt assembly is placed under heavy spring pressure in preparation for firing a respective cartridge. Just prior to a given bolt assembly cresting forward camming portion  21  of helical track  20  and entering the straight section thereof defined by sidewalls  25 , the cartridge is fired and the spring pressure is released. The bolt assembly continues through the straight section of helical track  20  defined by sidewalls  25  until reaching aft camming portion  22  of helical track  20 , at which point the bolt assembly is forced in the aft direction, guiding the bolt assembly back into the portion of helical track  20  within main housing  8 . It is forward camming portion  21  of helical track  20  that causes the cartridge to be fired and aft camming portion  22  of helical track  20  that redirects the bolt assembly and guides it back into the helical track  20  within main housing  8 . When safing the gun by partially or completely removing the prior art safing sector  31 , it is the removal of forward camming portion  21  of helical track  20  that inhibits the minigun from firing. In addition, when safing the gun, aft camming portion  22  of helical track  20  is also removed, further inhibiting the barrels from being rotated electrically. If the safing sector  31  is removed and the barrels are rotated electrically, the bolt assemblies will be damaged as the result of not being properly guided back into the portion of helical track  20  within main housing  8  by aft camming portion  22  of helical track  20 . 
         [0022]    Referring now generally to  FIGS. 5-10 , there is shown a top cover and safing blade assembly  1  in accordance with the present invention. Top cover and safing blade assembly  1  is adapted for attachment to main housing  8  of a conventional minigun and includes a top cover  2  and a safing blade  3 . Top cover  2  includes a pair of side retainer pin housings  13 ,  14 , a pair of spring-loaded retainer pins  4 ,  9 , a pair of retainer pin springs  32 , a bearing bushing  10 , a latching mechanism retainer  18 , and a plunger keeper  16 . Spring-loaded retainer pins  4 ,  9  serve to attach top cover and safing blade assembly  1  to main housing  8 . Retainer pins  4 ,  9  are spring loaded in their open or retracted position and extend through forward holes  6  of top cover  2  into locator holes in main housing  8 . Top cover and safing blade assembly  1  is attached to main housing  8  by pushing the retainer pins  4 ,  9  forward, against the pressure applied by retainer pin springs  32 , into the locator holes within main housing  8  and then locking them into the forward position by rotating a thumb tab  12 ,  19  of each of the retainer pins  4 ,  9  into their respective pin retainer notches  11 . Safing blade  3  is secured by and allowed to pivot about retainer pin  4  and retainer bushing  10  through an opening  5  in safing blade  3 . Safing blade  3  is secured in its closed position by a latching mechanism  17  thereof and a latching mechanism retainer  18  of top cover  2 . Latching mechanism  17  is spring-loaded in its extended or locked position and is retracted by depressing a tab  7 . When tab  7  is depressed, latching mechanism  17  is retracted to clear latching mechanism retainer  18  and allowing safing blade  3  to be rotated to its open position. 
         [0023]    In order to safe the gun, the safing blade  3  must be rotated from its closed position, as illustrated in  FIG. 7 , to its open position, as illustrated in  FIGS. 8 and 9 . The operator accomplishes this by depressing tab  7  and rotating safing blade  3  outward to its open position. When the safing blade  3  is fully open, a spring-loaded plunger  15 , incorporated in safing blade  3 , snaps into engagement with a plunger keeper  16  that is provided in top cover  2 . Safing blade  3  will remain open, and the gun will remain safed until the operator depresses plunger  15  to release its engagement with plunger keeper  16  and permit rotation of safing blade  3  to its closed position. Safing blade  3  may be locked in its closed position by first depressing tab  7  or by the preferred method of rapidly rotating safing blade  3  downward to thereby force latching mechanism  17  past latching mechanism retainer  18 . 
         [0024]    Referring now to  FIG. 10 , there is shown an underside view of top cover and safing blade assembly  1  of  FIG. 5 . The underside of safing blade  3  is depicted by the hatched area illustrated in  FIG. 10 . The geometry of forward and aft camming portions  21 ,  22  of helical track  20  is similar to the geometry of those same elements as depicted in  FIG. 4 . When safing blade  3  is in its open position or, in other words, when the gun is safed, as illustrated in  FIGS. 8 and 9 , forward camming portion  21  of helical track  20  is removed from the overall length of helical track  20 , leaving aft camming portion  22  thereof in place. With the forward camming portion  21  of helical track  20  removed and the aft camming portion  22  retained in its operational position, the barrels of the minigun may be rotated electrically without it firing and without the bolt assemblies thereof being damaged. 
         [0025]    In contrast to the prior art two-piece top cover  30  and safing sector  31  illustrated in  FIGS. 1-4 , the present invention combines the top cover  30  and aft camming portion  22  of helical track  20  into a single unit, top cover  2  of  FIGS. 5-10 , allowing forward camming portion  21  of helical track  20 , which is incorporated in safing blade  3 , to be removed separately. Safing the gun by means of opening safing blade  3  requires far less time and effort than prior art safing systems. Likewise, far less time is required to transition the minigun back to its armed and ready condition. In the event it becomes necessary for the operator to remove live cartridges from the minigun without firing them, safing blade  3  can be locked in its open position, and the minigun barrels can be rotated electrically to thereby quickly clear the minigun of live cartridges. 
         [0026]    To remove the top cover and safing blade assembly  1  from main housing  8 , thumb tabs  12 ,  19  of retainer pins  4 ,  9 , respectively, are rotated out of their pin retainer notches  11  and allowed to retract, under pressure exerted by locking pin spring  32 , from the locator holes within main housing  8 . This permits top cover and safing blade assembly  1  to be removed in its entirety from main housing  8 .