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United States Patent 3,921,499
Ginsky November 25, 1975

Ammunition cook-off sensing and prevention system

Abstract

An ammunition "cook-off" sensing and prevention system which is incorporated within a Gatling-type gun and therein indexes the gun barrels so that an ammunition round always is in position under an infra-red temperature sensor at the end of a firing cycle. If imminent "cook-off" of the round is indicated by the temperature sensor the gun is cycled at low speed until the heated ammunition rounds are removed from the high heat transfer area behind the gun barrels and replaced with cool rounds from the ammunition chute. If then necessary the cycle can be repeated. In this manner an extremely dangerous aspect of the Gatling-type gun is removed.


Inventors: Ginsky; Willard R. (San Diego, CA)
Assignee: The United States of America as represented by the Secretary of the Air (Washington, DC)
Appl. No.: 05/439,669
Filed: February 4, 1974


Current U.S. Class: 89/12 ; 89/14.1
Current International Class: F41A 17/00 (20060101); F41A 17/16 (20060101); F41D 011/20 ()
Field of Search: 89/1L,12,13R,13A,14A,135,137,138

References Cited

U.S. Patent Documents
2471806 May 1949 Wilson et al.
3618455 November 1971 Plumer et al.
Foreign Patent Documents
710,250 Jun., 1954 UK
Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Rusz; Joseph E. Erlich; Jacob N.

Claims



I claim:

1. An ammunition cook-off sensing and prevention system adapted for use with an automatic weapon having a plurality of barrels circumferentially arranged about a common axis, a rotor assembly supporting said barrels and a housing circumferentially spaced about and rotatably supporting said rotor assembly, said system comprising drive means for rotating said rotor assembly, means for supplying power to said drive means operably connected thereto, means mounted in a predetermined position adjacent said rotor assembly for sensing the heat emanating from an ammunition round carried by said rotor assembly, said sensing means being operably connected to said power supplying means and regulating means operably connected between said sensing means and said power supplying means for controlling the amount of power supplied to said drive means whereby said rotor assembly is rotated by said drive means when the heat emanating from an ammunition round is deemed to be above a predetermined temperature by said sensing means.

2. An ammunition cook-off sensing and prevention system as defined in claim 1 wherein said regulating means comprises a solenoid operably connected to said power supplying means causing the activation or deactivation thereof, a timer switch operably connecting said senser to said solenoid and an indexing switch operably connecting said rotor assembly to said solenoid.

3. An ammunition cook-off sensing and prevention system as defined in claim 2 wherein said drive means comprises a gear operably connected to said rotor assembly and a drive motor operably connected between said gear and said power supply.

4. An ammunition cook-off sensing and prevention system as defined in claim 3 wherein said gear has a plurality of detents therein and said indexing switch has a biased element thereon which is capable of engaging said detents in said gear, said detents being so positioned in said gear that when said biased element engages a detent said ammunition round is positioned adjacent said sensor.

5. An ammunition cook-off sensing and prevention system as defined in claim 4 wherein said drive motor is hydraulic in operation and said power supply supplies hydraulic fluid thereto.

6. An ammunition cook-off sensing and prevention system as defined in claim 5 wherein said sensor is an infrared temperature sensor.
Description



BACKGROUND OF THE INVENTION

This invention relates generally to high rates of fire automatic weapons of the Gatling-gun type, and, more particularly to a system which detects and is capable of preventing ammunition cook-off.

The typical Gatling-gun type of weapon now in use comprises a housing enclosing and supporting a rotor assembly. The rotor assembly, in turn, supports a plurality of bolt assemblies having individual firing mechanisms for igniting cartridges, electrically or by percussion. When the rotor is caused to revolve, either by means of an electric, hydraulic or gas (cartridge) drive, interaction between the housing and the rotor by means of cams and/or gearing causes the various weapon actions. In this way, the ammunition is fed to the gun, the cartridges chambered, the bolts locked for firing, the cartridges fired, and the empty cartridge cases extracted and ejected. The increasing need for improved multi-barrel, automatic weapons of the Gatling-gun type, having higher and higher rate-of-fire, has raised certain problems in the design of the guns.

One such problem encountered is a hazard known as cook-off which is the accidental detonation of a round caused by heating components of the round beyond self-ignition temperatures. Occurrence of this hazard is due to excessive heat build-up in the gun barrels. Automatic rapid fire guns by reason of their cyclic fire rapidly develop a large amount of heat. Part of this heat is constantly being transferred from the hot gun gases to the gun barrel which in a short time becomes very hot. The cleared position of automatic rapid fire guns always contains a live round or rounds and on interruption of firing with an excessive heat build-up in the gun barrel, heat detonation of cleared ammunition has been known to occur. This accidental detonation is especially dangerous when the round contains a high explosive. Where the gun is mounted on a plane and is equipped with a revolving firing chamber, rounds not in firing position which have been heat-detonated may cause damage to the plane.

Heretofore the only known successful method of eliminating the cook-off hazard in forward-firing, Gatling-gun cannon installations is by blocking the flow of ram air through the gun barrels. This has been accomplished by installing a door over the gun muzzle opening. Such an installation, however, is not only extremely expensive but also is unreliable in operation since in many instances the door mechanism becomes jammed. Such a malfunction constitutes a hazard in itself which may have more serious consequences than the initial ammunition cook-off problem.

SUMMARY OF THE INVENTION

The ammunition cook-off sensing and prevention system of this invention not only overcomes the problems set forth hereinabove but also introduces no additional hazards to the gun system.

The ammunition cook-off sensing and prevention system of the instant invention is made of an infra-red sensor which is focused upon the shoulder of an ammunition round in the retracted position at the breech of a Gatling-type gun. The gun barrels are indexed after a firing cycle by an indexing switch which continues to keep a solenoid activated and a low flow of hydraulic fluid through the gun drive motor. This operation continues until a detent in the driven gear face allows the indexing switch to open.

Heat stored in the gun barrels as the result of the firing is transferred to ram air flowing through the barrels and this heat is, in turn, transferred to the ammunition round. As the ammunition round case temperature reaches a critical set point a control box initiates a timer switch which activates the solenoid and the gun is rotated at low speed by the hydraulic motor until the heated rounds (at least six rounds) are removed from the breech area. The number of unfired rounds which are cycled through the gun will be a function of the set time of the timer switch and the flow area of the limiting orifice which controls gun rotation speed.

If, at the end of the timed interval, the gun stops in a non-indexed position, the barrel indexing switch will maintain gun rotation until the switch settles in a detent position. Thus, an unheated round will again be targeted under the sensor and, if sufficient heat remains in the barrel to heat this round to the critical temperature, the cycle will be repeated. The hydraulic feed line which provides low speed operation is equipped with a check valve which prevents interference with the normal firing of the gun at any time in the cycle.

It is therefore an object of this invention to provide a system which can be incorporated within a Gatling-type gun and is capable of detecting and thereby preventing ammunition cook-off.

It is another object of this invention to provide an ammunition cook-off sensing and prevention system which introduces no additional hazards to the Gatling-type gun.

It is a further object of this invention to provide an ammunition cook-off sensing and prevention system which is economical to produce, highly reliable in operation and which utilizes conventional currently available components that lend themselves to standard mass producing manufacturing techniques.

For a better understanding of the present invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE DRAWING

The only FIGURE of the drawing illustrates in pictorial and schematic fashion the ammunition cook-off sensing and prevention system of this invention incorporated within a Gatling-type gun.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to the only FIGURE of the drawing which shows in pictorial fashion the ammunition cook-off sensing and prevention system 10 of this invention utilized in co-operation with a conventional rapid fire automatic weapon 12 of the Gatling-gun type such as shown in Air Force Technical Manual TO 11W1-12-4-32 and U.S. Pat. Nos. 3,380,341 and 3,380,342. Gun 12 is typically an air-cooled, six barrel weapon capable of firing between 2,500 - 7,200 shots per minute. It utilizes a rotor assembly 14 which is rotatably mounted within a fixed rear housing assembly 16. Rotor assembly 14 supports a plurality of barrels, the chambers 17 of which are shown, at one end thereof, bolts 18 having individual firing mechanisms (not shown) and a driving means such as gear 19 at the other end thereof. When rotor assembly 14 is caused to revolve interaction between housing 16 and bolts 18 of rotor assembly 14 by means of cams and/or gearing causes the various weapon actions.

During the firing cycle of weapon 12 rotor assembly 14 rotates and bolt assembly 18 follows the elliptical main cam path 20 formed in the inner surface of housing 16. This action cams bolt 18 forward along the rotor tracks (not shown) and each bolt 18 in turn picks up a round 22 of ammunition for firing. After round 22 has been fired bolt 18 remains locked during the locking cam period until the projectile leaves the barrels 17 and gas pressure in the barrels 17 is reduced. As the bolt 18 nears the end of the front dwell of the cam path, front and rear unlocking cams (not shown) lift bolt 18 upward. The upward movement of bolt 18 disengages the bolt from the front locking dwell of the rotor assembly 14.

The clearing cycle of automatic weapon 12 begins when a clearing signal is supplied and bolt 18 continues along the clearing cam path 24. In this manner the unfired rounds 22 are cammed out of an extracter lip and ejected from the gun.

The ammunition cook-off sensing and prevention system of this invention is made up of a conventional infrared sensor 26 mounted in any suitable fashion so as to focus upon the shoulder of an ammunition round 22 in the retracted position as shown in the drawing. The same drive motor 28, which may be hydraulic, for example, and which operates gun 12 under normal conditions is also utilized with the instant invention. Motor 28 is operatively connected to drive gear 19 in any suitable manner such as by gear and pinion arrangement 30. An aircraft power source 32, for example, may provide the hydraulic fluid necessary for driving motor 28 in a manner to be described hereinbelow.

With the instant invention gear 19 has formed therein a plurality of detents 34 equal in number to the number of barrel chambers 17 contained within gun 12. In most cases there are six such detents 34. Any conventional "on-off switch" hereinafter referred to as indexing switch 36 is located adjacent gear 19 and has a spring biased element 38 thereon capable of engaging detents 34. When element 38 engages detent 34 indexing switch 36 is in the off position and signals a solenoid 37 thereby stopping the flow of fluid to drive motor 28. The stop signal from switch 36 to solenoid 37 can be overridden by a signal from sensor 26 in a manner to be described hereinbelow. Detents 34 are so positioned around gear 19 so that when element 38 engages a detent 34, a round of ammunition 22 has its shoulder adjacent sensor 26.

Sensor 26 is operatively connected by any conventional electrical wiring 39 to a conventional power supply and controller 40, a conventional timer switch 42, indexing switch 36 and a solenoid 37. If desired a check valve 46 may be associated with the sensing and prevention system 10 in order to prevent interference with the normal firing of gun 12 at any time during the cycle.

Under normal circumstances during the firing cycle described hereinabove, gun 12 is driven by motor 28 under the flow of hydraulic fluid from source 32 through lines 48 and 50 with the cook-off sensing and prevention system of this invention being inoperative. After completion of the firing cycle by the removal of the trigger force, for example, a signal to indexing switch 36 from gun 12 keeps solenoid 37 activated. In this manner a low flow of hydraulic fluid flows from source 32 through line 52 and through gun drive motor 28 for operation of the clearing cycles. This operation continues until a detent 34 within gear 29 allows element 38 of indexing switch 36 to open thereby stopping an ammunition round 22 adjacent infrared sensor 26. In this position the shoulder of ammunition round 22 is sensed by infrared sensor 26.

If the heat emanating from round 22 is insufficient to constitute a hazard, gun 12 returns to the firing cycle in a conventional manner. If, however, the heat reaches a critical temperature infrared sensor 26 sends a signal to control box 40 which initiates a timer 42 which in turn activates solenoid 37 so that the gun rotor assembly 14 is rotated in the clearing cycle at low speed by the hydraulic motor 28 until the heated rounds 22 are removed from weapon 12. The number of unfired rounds 22 which are cycled through the gun are determined by the set time of timer 42 and the flow area of the limiting orifice of line 52 which controls the gun rotation speed. If, at the end of the predetermined timed interval the gun rotor assembly 14 stops in a non-indexed position the indexing switch 36 will maintain the gun rotor assembly rotation until element 38 of switch 36 settles within a detent 34. In this manner a presumably unheated round 22 will again be targeted under sensor 26. If, however, sufficient heat remains in the gun barrel to heat this round to the critical temperature the above cycle will be repeated. The hydraulic feed line 52 which provides this low speed operation is equipped with a check value 46 which prevents interference with normal firing of the gun at any time during the cycle.

Although this invention has been described with reference to a particular embodiment it will be understood to those skilled in the art that this invention is also capable of a variety of alternative embodiments within the spirit and scope of the appended claims.

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