Abstract:
A dual action retention pawl for securing ammunition in a breech loading gun having a bore along a longitudinal axis of a barrel of the gun and a breech opening with a moveable breech block at a rear of the bore. The dual action retention pawl includes a base, a pawl arm, and an activation arm operably attached to the base. The pawl arm pivots to a retracted position in response to ammunition engaging the activation arm when the ammunition is loaded into the breech opening and returns to a retention position once the ammunition is loaded to retain the ammunition within the barrel of the gun. The pawl arm pivots to the retracted position in response to the breech block engaging the activation arm when the breech block is moved to close the breech opening.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to a propellant retention device. More particularly, the present invention relates to a retention pawl for retaining modular propellant increments in a gun barrel during a loading process.  
         BACKGROUND OF THE INVENTION  
         [0002]    Traditionally, most larger caliber guns, such as guns having a caliber of greater than 105 millimeters, are loaded with ammunition from a breech end of the gun barrel. This process typically involves removing a breech block from the breech end of the gun barrel to provide access to the breech end of the gun barrel. Next, a projectile is inserted into the gun barrel. Propellant is then placed into the gun barrel and the breech block is positioned over the breech end of the gun barrel.  
           [0003]    To enhance the ease of loading propellant into the gun barrel, the propellant is usually packaged in modular increments. By changing the number of increments loaded, the amount of force imparted to the projectile during the firing process can be varied.  
           [0004]    In most breech loading guns that separately load propellant, a lower surface of the gun barrel has a depression that forms a lip in the gun barrel. This lip is often referred to as a Swiss notch. As propellant increments are inserted into the gun barrel, the propellant increments are prevented from sliding backwardly out of the gun barrel by the lip. Once all of the propellant increments are loaded into the gun barrel, the breech block is moved into position behind the breech end of the gun barrel and thereby prepare the gun for firing.  
           [0005]    In order for the lip to be effective at retaining the propellant increments in the gun barrel, the gun barrel must be rotated to a substantially horizontal orientation before initiating the loading process. Such a procedure is particularly suited for manual loading processes because it is difficult for a person performing the loading process to insert the projectile and the propellant into the gun barrel when the gun barrel is oriented at an angle that substantially deviates from horizontal.  
           [0006]    It can be appreciated that the time needed to perform the loading operation is significantly increased by lowering the gun barrel from the desired firing orientation to a horizontal loading orientation. Additionally, once the gun is reloaded it must be raised from the loading orientation to the desired firing orientation before firing the gun.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention relates to a dual action retention pawl for securing ammunition components in a breech loading gun. The gun has a barrel with a bore along a longitudinal axis of the barrel. The gun also has a breech opening with a moveable breech block at a rear of the bore. The dual action retention pawl includes a base, a pawl arm and an activation arm.  
           [0008]    The base is operably attached to the barrel of the gun. The pawl arm and an activation arm are operably attached to the base such that the pawl arm pivots to a retracted position in response to an ammunition component engaging the activation arm when the ammunition component is loaded into the breech opening and returns to a retention position once the ammunition component is loaded to retain the ammunition component within the barrel of the gun. The pawl arm pivots to the retracted position in response to the breech block engaging the activation arm when the breech block is moved to close the breech opening. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a side view of a propellant retention device of the present invention attached to a gun barrel.  
         [0010]    [0010]FIG. 2 is a front view of the propellant retention device attached to the gun barrel.  
         [0011]    [0011]FIG. 3 is a perspective view of the propellant retention device in a retention configuration.  
         [0012]    [0012]FIG. 4 is a side view of the propellant retention device in the retention position.  
         [0013]    [0013]FIG. 5 is a side view of the propellant retention device in a fully retracted position.  
         [0014]    [0014]FIG. 6 is a side view of the propellant retention device in a partially retracted position. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0015]    The present invention is directed to a propellant retention device, as most clearly illustrated at 10 in FIGS. 1 and 2. The propellant retention device  10  retains ammunition components  12  as they are loaded into a gun barrel  14 . Ammunition components  12  can include one or more projectile and one or more modular propellant packets or increments.  
         [0016]    The propellant retention device  10  prevents ammunition components  12  from falling out of a breech end  16  of the gun barrel  14  during manual or automated loading processes. The propellant retention device  10  of the present invention thereby enhances the ease and safety of the loading process. The propellant retention device  10  also enhances the ability to reload the gun at a variety of orientations including orientations that are near vertical.  
         [0017]    The propellant retention device  10  is particularly suited for use with larger size guns where the propellant is loaded separately from the projectile. The gun barrel  14  preferably has a caliber of greater than 50 millimeters and, more preferably, is about 155 millimeters.  
         [0018]    The propellant retention device  10  generally includes a base  20  and an arm assembly  22 . The base  20  is mounted to an outer surface  24  of the gun barrel  14  proximate to the breech end  16  of the gun barrel  14 .  
         [0019]    The arm assembly  22  preferably has an over center configuration. When in a retention position, the arm assembly  22  extends preferably about 30 millimeters into the gun barrel  14 . When in the retracted position, the arm assembly  22  does not intrude into the gun barrel  14  to thereby permit the breech end  16  of the gun barrel  14  to be sealed for firing.  
         [0020]    The arm assembly  22  generally includes activation arm  30  and a retention pawl  32 , as most clearly illustrated in FIGS. 3 and 4. The retention pawl  32  is operably attached to the activation arm  30  such that movement of the activation arm  30  between the retention position, as illustrated in FIG. 4, and a retracted position, as illustrated in FIG. 5, causes the retention pawl  32  to move between the retention position, as illustrated in FIG. 4, and a retracted position, as illustrated in FIG. 5.  
         [0021]    The activation arm  30  preferably has a generally U-shaped configuration, as most clearly illustrated in FIGS. 3 and 4. A first leg  34  of the activation arm  30  is used for moving the propellant retention device  10  between the retention and retracted positions. A second leg  36  operably connects the activation arm  30  to the retention pawl  32 .  
         [0022]    The activation arm  30  is pivotally attached to the base  20  intermediate the first leg  34  and the second leg  36  for rotation about a first mounting shaft  40 . A biasing mechanism  42 , such as a spring, urges the activation arm  30  to the retention position.  
         [0023]    Opposite the first mounting shaft  40 , the first leg  34  preferably includes a roller  42  rotatably mounted thereto. The roller  42  has a diameter that is slightly greater than a thickness of the first leg  34  so that the roller  42  extends above the side and end surfaces of the first leg  34 . The roller  42  enhances the ability to slide the ammunition components  12  past the activation arm  30 .  
         [0024]    To further enhance the ability to move the ammunition components  12  past the activation arm  30 , the activation arm  30  preferably includes a lower region  46  and an upper region  44  that are oriented at an angle with respect to each other. The angle a between the lower region  46  and the upper region  44  is less than 180°, preferably between 120° and 170°, and more preferably about 140°.  
         [0025]    The retention pawl  32  is preferably operatively attached to the second leg  36  of the activation arm  30  using a first connecting member  60 . A first end  62  of the first connecting member  60  is pivotally attached to the second leg  36  using a second mounting shaft  64 . A second end  66  of the first connecting member  60  is pivotally attached to the retention pawl  32  with a third mounting shaft  68 . The second leg  36  preferably includes two leg sections that are oriented on either side of the first connecting member  60 .  
         [0026]    The retention pawl  32  is preferably operatively attached to the base  20  using a second connecting member  70 . A first end  72  of the second connecting member  70  is pivotally attached to the base using a fourth mounting shaft  74 . A second end  76  of the second connecting member  70  is pivotally attached to the retention pawl  32  with the third mounting shaft  68 .  
         [0027]    The second connecting member  70  preferably includes two sections that are attached on either side of the retention pawl  32 . The two sections are preferably shaped substantially identical to each other. Using the two section configuration enhances the lateral stability of the retention pawl  32 .  
         [0028]    The third mounting shaft  68  also pivotally attaches the first connecting member  60  to the second connecting member  70 . A biasing mechanism  80 , such as a spring, urges the retention pawl  32  to pivot away from the second connecting member  70  towards the retention position.  
         [0029]    The retention pawl  32  preferably includes an elongated main portion  82  and an end portion  84 . The end portion  84  is oriented substantially perpendicular to the main portion  82  and thereby provides a relatively large surface that retains the ammunition components  12  in the gun barrel  14 .  
         [0030]    The propellant retention mechanism  10  also preferably includes a sensor mechanism  90  that senses whether the propellant retention mechanism  10  is in the retention position. The sensor mechanism  90  thereby provides an additional level of safety during the propellant loading process. For example, if the sensor mechanism  90  senses that the propellant retention mechanism  10  does not return to the retention position after the insertion of the ammunition components  12  into the gun barrel  14 , the sensor mechanism  90  notifies the operator of the error and halts the automatic loading process.  
         [0031]    The sensor mechanism  90  preferably includes a cam  92  attached to an end of the first mounting shaft  40 . The cam  92  includes at least one region that has a greater height. The sensor mechanism  90  also includes a sensor  94  that is attached to the base  20 . Certain angular orientations of the cam  92  engage the sensor  94  and thereby indicate that the propellant retention device  10  is in an appropriate angular orientation. A person of ordinary skill in the art will appreciate that it is possible to sense the position of the propellant retention device  10  using a variety of techniques using the concepts of the present invention.  
         [0032]    The components of the propellant retention device  10  are preferably fabricated from high strength metallic materials such as steel. The thickness of the individual components is selected such that the components do not exhibit deformation over repeated uses of the propellant retention device  10 . A person of ordinary skill in the art will appreciate that care must be taken selecting components with sufficient structural integrity to withstand deformation as failure of the propellant retention device  10  can lead to damage of the ammunition components  12  thereby creating a significant risk of injury to people or equipment in close proximity thereto.  
         [0033]    In operation, the propellant retention device  10  is initially in the retention position, as illustrated in FIGS. 1 and 4. During the process of inserting the ammunition components  12 , the ammunition component  12  slides along a central axis  118  of the gun barrel  14 , as indicated by arrow  120  in FIG. 1, and contacts the upper portion  44  of the activation arm  30 . The ammunition component  12  urges the activation arm  30  to pivot towards the base  20 , as indicated by arrow  100 . As noted above, the term ammunition component  12  encompasses both the projectile and the propellant increments.  
         [0034]    Pivoting of the activation arm  30  towards the base  20  causes the first connecting arm  60  to pivot the second connecting member  70  towards the activation arm  30 , as indicated by arrow  102 . Continued pivoting of the activation arm  30  causes the arm assembly  22  to be further retracted into the base  20 .  
         [0035]    The activation arm  30  then contacts the retention pawl  32  and causes the retention pawl  32  to be further pivoted into the base  20 , as illustrated in FIG. 6. Pivoting continues until the ammunition component  12  may slide past the activation arm  30  and into the gun barrel  14 .  
         [0036]    Once the ammunition component  12  moves past the end of the activation arm  30 , the force of the spring  42  causes the activation arm  30  to pivot back to the retention position. Pivoting of the activation arm  30  causes the second connecting member  70  to pivot with respect to the base  20 . This process continues until the activation arm  30  is in the retention position. The spring  80  biases the retention pawl  32  away from the second connecting member  70 . The retention pawl  32  is thereby positioned in the breech end  16 , as illustrated in FIG. 1, of the gun barrel  14  to prevent the propellant packet from falling out of the gun barrel  14 .  
         [0037]    During this process, the projectile and from  1  to  6  propellant increments  12  are loaded into the gun barrel  14 . The structure of the propellant retention device  10  of the present invention is particularly suited for automatic propellant loading operations to thereby increase the safety associated with this process.  
         [0038]    After all of the ammunition components  12  have been inserted into the gun barrel  14 , it is necessary for a breech block  110  to be moved into position over the breech end  16  of the gun barrel  14  prior to firing. The breech block  110  is preferably slid along an axis that is substantially perpendicular to the central axis  118  of the gun barrel  14 , as indicated by arrow  122  in FIG. 1, and contacts the lower portion  46  of the activation arm  30  and urges the activation arm  30  to pivot towards the base  20 , as indicated by arrow  100  in FIG. 4.  
         [0039]    Pivoting of the activation arm  30  towards the base  20  causes the first connecting arm  60  to pivot the second connecting member  70  towards the activation arm  30  as indicated by arrow  102 . Continued pivoting of the activation arm  30  causes the components of the propellant retention device  10  to be further retracted into the base  20 .  
         [0040]    The activation arm  30  then contacts the retention pawl  32  and causes the retention pawl  32  to be further pivoted into the base  20 , as illustrated in FIG. 6. Pivoting continues until the activation arm  30  and the retention pawl  32  are located substantially within the base  20 , as illustrated in FIG. 5. At this point, the breech block  110  is fully closed and ready to fire.  
         [0041]    After the gun is fired and it is necessary to reload the gun, the breech block  110  is slid away from the breech end  16  of the gun barrel  14 . As the breech block  110  moves away from the propellant retention device  10 , the force of the spring  42  causes the activation arm  30  to pivot towards the retention position. Pivoting of the activation arm  30  causes the second connecting member  70  to pivot with respect to the base  20 . This process continues until the activation arm  30  is in the retention position. The spring  80  biases the retention pawl  32  away from the second connecting member  70 . The retention pawl  32  is thereby positioned in the breech end  16 , as illustrated in FIG. 1.  
         [0042]    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.