Abstract:
A liquid propellant gun loading, propellant injection and firing mechanismharacterized by a rotating breech block having a generally spherical contour. The breech block is intermittently rotated to and locked in sequential loading, fuel injection and firing positions.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to liquid propellant guns and particularly to a novel loading, propellant injection and firing mechanism. 
     2. Description of the Prior Art. 
     Generally, liquid propellant guns all contain a mechanism for injecting the propellant. Current designs use injection valves which cannot be exposed to high firing pressures and the injection mechanism is therefore protected from the firing pressures by using a sliding bolt. After injection, for example, the bolt moves forward in the breech, pushing the propellant column and projectile before it down the bore, until a bolt seal is ahead of the injector area. An example of this type of gun is disclosed in assignee&#39;s prior application, Ser. No. 612,817 filed Sept. 12, 1975, and now U.S. Pat. No. 3,992,976 issued Nov. 23, 1976. Although this prior design operates satisfactorily, the bolt actuating and locking system is complicated, has high power requirements and slows the rate of fire because of the start and stop action. 
     SUMMARY OF THE INVENTION 
     According to the present invention, the propellant injection valve mechanism and the firing device are arranged in space relationship within a rotary breech block in the same general plane with a central bore, orthogonal to the axis of rotation of the block. The breech block also includes an axial liquid propellant transfer arrangement designed to supply a liquid fuel and an oxidizer to the injection valve mechanism. The rotary breech block herein disclosed completely protects the injection system by moving the valve mechanism out of register with the firing chamber before ignition. The rotary breech block mechanism is designed to be moved intermittently through at least 3 sequential positions for loading, injection and firing respectively. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal cross sectional view in the breech area of a liquid propellant gun according to the present invention; 
     FIG. 3 is a cross sectional view of the FIG. 1 mechanism taken along line II--II; 
     FIG. 2 is a schematic plan view of the drive mechanism of FIG. 1; 
     FIG. 4 is a view similar to FIG. 2 showing the rotary bolt in the firing position; and 
     FIG. 5 is a view similar to FIG. 2 with the bolt in the loading position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A rotary bolt liquid propellant gun breech area incorporating the present invention is generally indicated at 10 in FIG. 1. The loading end of the breech area is generally indicated at 12; the barrel is generally indicated at 14; and the rotary breech block is generally indicated at 16. A round 18 is shown in the barrel and a round 18a is shown in the load area. 
     The rotary breech block 16 is rotatably mounted in the breech area by means of two bearings 20, 21 and receives fuel and oxidizer through a rotary joint between a transfer housing sleeve 22 fixed on the block and a stationary transfer or feed tube 24. In the embodiment illustrated, the feed tube 24 is divided into two separate channels 26, 28 which supply an oxidizer and fuel respectively. The breech block end of delivery tube 24 rests in a bearing 30 fixed in the face of block 16. 
     Between bearings 20 and 21 the outer surface of breech block 16 is spherical in contour and closely fits within mating concave spherical contours in the loading end 12 and barrel end respectively of breech area 10. In the embodiment shown, block 16 contains two identical poppet valves 32, 32a; two identical firing devices 34, 34a (see FIG. 3) and a central bore 36. 
     The breech block 16 is designed to be driven intermittently and, for this purpose, carries a six lobed geneva wheel 38 integral with the face of breech block 16 opposite feed tube 24, and coaxial thereto. The geneva wheel 38 is driven by a geneva wheel driver 40 which, inturn, may be driven by a constant speed motor (not shown) through shaft 42. FIG. 2 illustrates how a pin 44 on geneva wheel driver 40 cooperates with slots 46 on geneva wheel 38 to intermittently drive wheel 38. Between drive periods, a locking surface or cam 48 cooperates with one of the surfaces 50 between slots on geneva wheel 38 to prevent any movement of wheel 38 during that time. 
     FIGS. 1 and 3 illustrate the device at the beginning of an injection cycle. Valve 32 is in position to receive fuel and oxidizer through ports 26, 28 and when pressure is applied by the fuel and oxidizer the valve body 52 will be pushed back by this pressure against the bias of spring 54 and chamber 56 will be filled with liquid, pushing the round 18 forward in the barrel as shown in FIG. 4. Pressure will also act upon chamber seal 58 to press against the spherical surface of breech block 16. 
     After injection of the measured amount of propellant has been accomplished, the breech block is next rotated to the position shown in FIG. 4 with the igniter 34 in position to ignite the fuel in chamber 56, forcing the round 18 out of the barrel. Following this step, the next increment of rotation of block 6 places the parts in the position shown in FIG. 5, allowing the round 18a to be advanced through the bore 36 into chamber 56. This may be accomplished mechanically, for example, by a ram (not shown) or by pneumatic pressure. 
     The igniter shown in the above embodiment is shown as an electrical spark type but it may, of course, be any type of igniter suitable for the purpose. Similarly, the drive mechanism is shown as a geneva type drive but any intermittent drive which will lock at each position would serve as well. The same rotary breech block concept can be adapted to small or large bore guns. 
     This invention completely protects the injector mechanism from gun gas pressures at ignition by moving the valve mechanism out of the chamber area before firing. The sealing surfaces consist of easily machined spherical contours and no bolt lock mechanism is required. 
     For a firing speed of about a thousand rounds per minute, the shaft 42 of the geneva wheel driver rotates at a constant 3,000 revolutions per minute. At this speed, the geneva mechanism will cause the breech block to dwell at each station for about 13 milliseconds. The six lobed geneva wheel and the duplicate valves and igniters are used to reduce breech block acceleration and drive motor power requirements. For slower rates of fire, a three or four station block could be used with a three or four lobed geneva wheel, for example, to further reduce size and increase dwell time at each position.