United States Patent [191 Corbin, Jr.
[4 1 Sept. 16, 1975 CARTRIDGE-ACTUATED DEVICE AND LAUNCHING ASSEMBLY USING SANIE George T. Corbin, Jr., Cinnaminson, NJ. 08077 [22] Filed: Apr. 11, 1973 [21] App]. No.: 350,194
[76] Inventor:
2,939,365 6/1960 Vaiden 89/1 D 3,249,049 5/1966 Zimmerman. 102/46 3,618,521 11/1971 Montesi 102/24 R 3,726,220 4/1973 MacDonald et a1. 102/39 3,779,167 12/1973 Irish, Jr. et al.... 102/46 Primary ExaminerVerlin R. Pendegrass Attorney, Agent, or Firm1-lowson and Howson [5 7] ABSTRACT A cartridge-actuated device suitable for use in launching sonobuoys or the like from a launching tube on an aircraft, having improved safety features, A cylindrical container made up of an inner cylindrical shell screwed into an outer cylindrical shell encloses an explosive cartridge and has a gas-metering outlet in the closed end of the inner shell for releasing a propelling gas when the cartridge is detonated by an electrical current to propel the sonobuoy from the launching tube. If the gas-metering outlet should become blocked, high gas pressures will build up in the cartridge container following detonation, which pressures might cause the container to blow apart and injure personnel or equipment at the breech end of the device. The outer cylindrical shell is made of a single metal piece through which the electrical contact for detonating the cartridge extends; threads on the outside of the outer cylindrical shell mate with corresponding threads on a main support frame, so that if any parts of the inner shell should break away they will be propelled in the launch direction rather than towards the breech end of the device. A resilient O- ring seal prevents hot propellant gases in the container from reaching and passing between the threads joining the two cylindrical parts, thereby preventing fusing of the threads and breaking away of the inner cylindrical shell, or bursting of the outer cylindrical shell. A frangible rupture disc at the downstream end of the inner cylindrical shell breaks away to relieve dangerously high pressures which may occur upon blockage of the metering outlet. The electrical contact for the cartridge is recessed in a cylindrical metal-walled depression by a distance at least about one-half the diameter of the depression, to protect against accidental deto nation of the cartridge by static electrical discharges.
4 Claims, 7 Drawing Figures FIG 2 (PRIOR ART) SHEET 1 BF 2 ATENTEBSEP 61975 CARTRIDGE-ACTUATED DEVICE AND LAUNCHING ASSEMBLY USING SAL IE BACKGROUND OF THE INVENTION This invention relates to cartridge-actuated devices and to launching assemblies using the same; it especially relates to improved features which make the cartridge-actuated device safer prior to and during use.
There are many known applications for cartridgeactuated devices of the type in which an explosive cartridge within a container is detonated to produce a sudden strong flow of propellant gases through an outlet in the container. For example, such cartridge-actuated devices have been utilized to launch various types of military stores from a launching tube associated with the cartridge-actuated device. As one example, sonobuoys for detecting underwater submarine operations have been launched from launching tubes in aircraft, such as helicopters, so as to be initially impelled away from the aircraft and then to fall into the water and float in the desired area.
In one known form of such cartridge actuated device, a first cylindrical shell having a gas metering bore extending through one closed end thereof is threaded into another cylindrical cap containing the explosive cartridge, the detonating contact for which is exposed through the closed end of the cap. The inner cylindrical shell is provided on its exterior surface with threads which mate with a breech cap at the breech end of a launch container containing the stores, such as a sonobuoy, which are to be launched out of the opposite muzzle end of the launch container. The supporting frame for the launch container on the aircraft is typically in the form of a tube having inwardly-extending lock tabs for engaging ears on the exterior of the launch container breech cap. The entire launch assembly, including the cartridge-actuated device and the launch container, is manually inserted into the launch tube and rotated to engage the breech cap ears With the protruding tabs in the surrounding tube and thus mount the assembly preparatory to launching. When the launch container is thus installed, the detonating contact associated with the cartridge has moved into electrical contact with an external spring-mounted contact pin, and when the sonobuoy is to be launched an electrical current is passed through the contact pin and contact to the cartridge to cause it to explode. The resultant rush of propelling gases through the metering outlet propels the sonobuoy or other stores outwardly through the launch end of the launch container as desired.
It has been found that there are several dangerous features associated with such previously-known cartridge-actuated devices. One such primary danger arises when the gas-metering outlet is by chance partially or completely blocked, and the cartridge is detonated. Under these conditions, extremely high pressures of hot gases occur within the cartridge-actuated device tending to cause it to explode. If the screwed-on cap bursts, parts thereof may be propelled outwardly through the breech end of the device to cause hazard to personnel or equipment located within the aircraft, for example. It has also been found that the hot highpressure gases may leak outwardly between threads joining together the two parts of the cartridge con tainer, fusing the threads and permitting the cap to be blown off along the breech direction, with the same ha- LII zards mentioned above. Additionally, such a flow of hot gases along the threads tends to heat the cap rapidly, thus opposing the strengthening effect which has been found to occur in the absence of such gas flow along the threads, due to the initial more-rapid expansion of the inner threaded shell causing it to lock up against the outer cap and provide a generally firmer and stronger container.
A further hazard arises from the exposure of the cartridge contact to the external environment. If a chance spark should occur in the adjacent environment and strike the cartridge contact, the resultant current can cause the cartridge to explode before it is even placed into position for effecting a launch. For example, static electricity oftens build up in airplanes to such an extent that a person carrying a cartridge-actuating device near the metal frame of the aircraft may encounter a static discharge, causing the cartridge to explode while it is being transported or while it is stored, with resultant hazards to personnel and equipment nearby.
Accordingly, it is an object of the invention to provide a new and useful cartridge-actuated device.
A further object is to provide a launching system utilizing such cartridge-actuated device.
A further object is to provide a cartridge-actuated device which is safer and less hazardous than previously known cartridge-actuated devices.
It is also an object to provide a cartridge-actuated device which is less likely to explode prematurely, with hazard to adjacent personnel and equipment.
It is also an object to provide a cartridge-actuated device which is less susceptible to actuation by stray elec' trical discharges.
SUMMARY OF THE INVENTION In accordance with the invention, one or more of the following features of improvement are employed to enhance the safety of the resultant device. The cartridge container comprises two parts mounted to each other, the end of one of which contains the gas-releasing means; the other part comprises an integral member extending around and about the opposite or breech end of the container and is securely mounted to the adjacent supporting frame both during a normal operation and during an abnormal operation in which the gasreleasing means is blocked. Preferably this mounting is provided by threads on the exterior of the breech-end part of the container. Because of this general arrangement, even if the high internal pressures generated during abnormal operation should cause the explosive separation of the two parts of the container, the upstream or breech-end part of the container Will remain mounted to the supporting frame, and only the other, muzzle end part will be propelled away, in the launch direction. Accordingly, with this kind of a failure the parts of the device will not be propelled in the breech or upstream direction where they might cause injury to personnel or equipment. In addition, resilient gassealing means, such as an O-ring, is provided to prevent the internal pressurized gases from leaking through the threads joining the two parts of the container, thereby to prevent heat-induced damage to the threads which might weaken them and make more likely the abovedescribed separation of the two parts from each other in response to abnormally high internal pressures. The downstream part of the cartridge container has a frangible portion, preferably a rupture disk, designed to burst and release the pressure in the cartridge container before any other portion of the container bursts, so that upon an abnormal operation of the cartridgeactuated device it may be simply and safely removed and replaced with another. Also, the contact responsive to the electric current for detonating the cartridge is positioned in a depression, the walls of which are metal, the contact being recessed below the top of the depression by a distance of at least one-half the average diameter of the depression. Static discharges will then in most cases occur to the walls of the depression if they enter it at all, rather than reaching the contact at the bottom of the depression, and the hazard of chance detonation by static electricity or the like is thus greatly reduced.
BRIEF DESCRIPTION OF FIGURES Other objects and features of the invention will be more readily understood from a consideration of the following detailed description, taken in connection with the accompanying drawings, in which:
FIG. 1 is a vertical elevational view, partly in section with parts broken away, showing a launching assembly to which the present invention is applicable;
FIG. 2 is an enlarged fragmentary sectional view showing a cartridge-actuated device of the prior art usable in the assembly of FIG. 1;
FIG. 3 is a vertical sectional view of one form of cartridge-actuated device in accordance with the invention, as it may be used in the assembly of FIG. 1;
FIG. 4 is a fragmentary enlarged view of a portion of the device of FIG. 3;
FIG. 5 is a section taken along line 55 of FIG. 3;
FIG. 6 is a fragmentary sectional view illustrating an alternative arrangement of O-ring suitable for use in the inventive device of FIG. 3; and
FIG. 7 is a fragmentary sectional view illustrating an alternative form for the portion of the device shown in FIG. 4.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS FIG. 1 illustrates a launching assembly suitable for launching stores, such as a sonobuoy, from an aircraft. In this example the generally cylindrical sonobuoy 10 is positioned within a cylindrical launch container 12 and held therein, at the muzzle end, by a muzzle breakout insert 14 having shear tabs 16 engaged in slots 17 in a muzzle cap ring 18. The muzzle breakout insert is installed by pressing it into position in the muzzle cap rin g and then rotating it to the position shown for which the shear tabs engage the slots 17, in which position it is appropriately locked against rotation by a spring locking catch (not shown). This portion of the device being well known in the prior-art, it is not necessary to show and describe it in further detail. Suffice it to say that when the sonobuoy is launched through the muzzle end of the launch container 12, the shear tabs 16 are broken by the force of the propulsion and the muzzle breakout insert is swept away as the sonobuoy is launched.
The upper end of the sonobuoy engages a plastic obturator 22 which extends slidably across the inner crosssection of the launch container 12. Above the obturator is a cushioning mass 24 of a material such as urethane foam, compressed by the sliding of the obturator into the position shown. The upper end of the launch container 12 is provided with a metal breech cap 26 having several outwardlyextending ears such as 28 which, when the launch container is placed in the position shown and rotated slightly, engage lock tabs 30 extending inwardly from the surrounding supporting frame 34, in this case comprising a metal launch tube. Launch tube 34 has a mounting flange 36 adjacent the muzzle end thereof, and other appropriate support means (not shown) may be provided along it or near the breech end of the launch tube. The mounting flange 36 may be mounted on the external structure of an aircraft and extends about a launch opening 38 therein, through which launching takes place.
The launch container breech cap 26 is centrally apertured and internally threaded to engage external threads 40 of a cartridge-actuated device 42. An upper closure 44 extends across the upper end of the launch tube 34 and is provided with a central contact pin opening 48 through which a resiliently-mounted contact pin 50 extends. Contact pin 50 is mounted above the closure 44, and extends through opening 48 to engage a corresponding electrical contact within the cartridge-actuated device 42, as will be described hereinafter.
In assembling the launching assembly of FIG. 1, the launch tube 34 is mounted permanently in the aircraft. The cartridge-actuated device 42 is screwed into position in the breech cap 26 before the launch container 12 is inserted into the launch tube. The uncompressed cushioning mass 24 is inserted into the muzzle end of the launch container, the obturator 22 is positioned in and across the interior of the launch container, and the sonobuoy 10 is slid into the launch container through the muzzle end, pushing the obturator 22 and the cushioning mass of urethane foam upward until the upper end of the obturator abuts the shoulder 49 on the inner wall of the launch container. The muzzle cap insert 14 is then inserted and turned into the locked position shown. The entire launch container assembly just described is then inserted into the muzzle end of the launch tube, slid upwardly therein and, when it reaches its uppermost position, is manually rotated to engage the ears 28 in the lock tabs 30. When the launch container is in this position, the contact pin 50 engages an electrical contact in the cartridge-actuated device 42, and the unit is ready for launching of the sonobuoy.
When launching is desired, operation of an electrical switch applies a current to the electrical contact in the cartridge-actuated device 42 by way of the contact pin 50, causing the cartridge in device 42 to explode and generate instantly a high gas pressure of approximately 20,000 psig within the interior of the cartridgeactuated device. This gas immediately begins to flow through a gas-release orifice or metering outlet at the lower end of the cartridge-actuated device, and is released at approximately psig into the upper end of the launch container 12. This pressure acting on the upper side of the obturator 22 urges the sonobuoy 10 against the muzzle breakout insert 13 until the shear tabs 16 shear off and the sonobuoy is launched from the muzzle of the launch tube by the propelling pressure.
FIG. 2 shows a cartridge-actuated device of the prior art which has been used in the past in the launch assembly of FIG. 1. The cartridge-actuated device comprises a cartridge container containing an explosive cartridge 51 and comprising a cylinder chamber 52 having a closed lower end and an open upper end. The cylinder chamber 52 is providednear its lower end with external threads 56 engaging corresponding threads in the breech cap 26, into which it can be tightly screwed by means of the wrench flats 58, until the flange 60 thereof abuts the upper surface of the breech cap. The exterior of the upper end of the cylinder chamber 52 is provided with external threads 64 on which the internally-threaded cap 66 is tightly screwed.
The cap 66 is centrally apertured and provided with an insulating bushing 70 into which there extends the electrical contact or firing pin 72 for actuating the cartridge. The contact pin 50 extends against the firing pin or contact 72, as described in connection with FIG. 1, when the device is in position for launch.
The lower end of the cylinder chamber 52 is provided with gas-releasing orifice device 76 in the form of a large hex-headed screw, which is screwed into threads 78 in a large bore through the bottom end of the cylinder chamber 52 until the head of the orifice device 76 bears against the bottom interior wall of the cylinder chamber, as shown. Orifice device 76 is provided with a dead-ended longitudinal bore 80, and with a plurality of transverse bores such as 82 intersecting it, providing a flow passage for gases in the cartridge-actuated device to be metered to the exterior.
In the arrangement of FIG. 2, if the longitudinal bore 80, or even one or more of the transverse bores 82, of the orifice device 76 are blocked by foreign matter or by imperfection in manufacture, upon explosion of the cartridge 51 extremely high gas pressures will be produced within the cylinder chamber 52. This can cause the cap 66 to be blown off toward the upper, or breech end, of the launching tube 34, damaging the upper closure 44 in FIG. 1 or breaking through it with consequent hazard to personnel and equipment in the aircraft.
The blowing off of the cap 66 is in some cases expedited by the hot high-pressure gases flowing along the external cartridge walls at the upper end of the cylinder chamber 52 and then along the space between the threads 64 to the exterior. These hot gases can weaken or even fuse the threads holding on the cap 66, in such a way as to facilitate blowing off of the cap. Also, if the cartridge 51 explodes and in fact there is substantially no gas leakage from the cartridge-actuated device, there is the problem of disposing of the highlypressurized device upon such a failure. Furthermore, when the cartridge-actuated device of FIG. 2 is stored, or is being carried about before its installation in the launch tube, a static discharge of electricity may on occasion strike the firing pin 72, causing the cartridge 51 to explode with resultant possible harm to personnel and equipment nearby.
FIGS. 36 illustrate an embodiment of the invention comprising a cartridge-actuated device of improved safety suitable for replacing the prior-art cartridgeactuated device of FIG. 2 in assemblies such as that shown in FIG. 1. Parts of FIGS. 36 corresponding to parts in FIGS. 1 and 2 are designated by corresponding numerals.
In this embodiment the cartridge container is again made in two parts, an outer unitary metal part 90 having an open, threaded, lower end extending integrally about the upper end of the cartridge-actuated device. In this example the cartridge container part 90 is a cylinder or shell, and is provided at its lower end with external threads 40 engaging corresponding internal threads of the breech cap 26 to mount the cartridgeactuated device in the upper end of the launch containerfThe other cartridge container part comprises an inner metal cylinder or shell 96 provided near its lower end with external threads 98 mating with corresponding internal threads of the outer cylinder and having an open upper end for receiving the explosive cartridge assembly.
The bottom of the inner cylinder 96 is provided with the orifice device 76, which may be like that in the prior-art device of FIG. 2. The lower end of the inner cylinder 96 is also provided not only with the spanner wrench holes 99, but also with a concentric annular recess 100 forming a weakened frangible portion near the center of the lower end of cylinder 96, thereby providing in effect a rupture ring so that the weakened bottom wall will break out in response to abnormally high pressures produced inside the cartridge-actuated device in the event of explosion of the cartridge with the orifice device blocked.
The cartridge 51 with its associated detonator 104 is provided with an upper flange member 106 overlapping the walls of the inner cylinder 96 at the top thereof to prevent the cartridge from moving downwardly within cylinder 96. An annular groove 110 in the inner wall of inner cylinder 96 near its upper end receives a resilient O-ring l 12 and a plastic backup ring 114 providing a high-pressure gas seal between the outer wall of the cartridge 51 and the inner wall of the upper end of cylinder 96. This O-ring is so located that when hot high-pressure gases are formed by explosion of the cartridge device, they are prevented from passing between the outer walls of the cartridge and the inner walls of the inner cylinder 96, and thence along the junction between the inner walls of the outer cylinder 90 and the outer walls of the inner cylinder 96 and along the threads 98 to the exterior of the cartridge-actuated device.
As best shown in FIG. 4, an electric contact or firing pin 1 16 having a conical depression in its upper surface is force-fitted into an electrically insulating plastic bushing 1 18, which itself fits closely with a corresponding counterbore in the interior surface of the upper end wall of the outer cylinder 90. The lower end of the firing pin 116 protrudes downwardly into contact with the metal boss 124 at the top of the detonator 104 of cartridge 51, and into electrical contact therewith, when the inner cylinder 96 has been screwed completely into the outer cylinder 90. An insulating covering extends into the detonator and serves to electrically insulate the firing pin and electrical parts connected thereto from the surrounding metal structure.
F IG, 6 shows an alternate location for the O-ring gas sealing arrangement. In this case the annular groove 130 is formed in the outer wall of the upper end of the inner cylinder 96, and the resilient O-ring 112a and associated plastic backup ring 114a are positioned therein as shown so as to provide a gas seal isolating the interior of the inner cylinder 96 below cartridge 51 from the threads 98 between the inner and outer cylinders.
It is further noted that a concentric cylinder depression or bore is provided in the outer surface of the top end of the outer cylinder 90, through which bore the resiliently-mounted contacting pin 50 enters to make contact with the firing pin 116. As shown, the
depth of the depression 140 is such that the top of the firing pin 116 is recessed below the level of the exterior surface of the depression by a distance which is greater than one-half the diameter of the cylindrical depression 140.
FIG. 7 shows a modification of the portion of the device illustrated in FIGS. 3 and 4, corresponding numerals indicating corresponding parts. The version of FIG. 4 is particularly useful where a monitoring device such as a computer is used to sense the time of detonation by sensing the opening of the electrical circuit though which current is supplied to the firing pin 116. When detonation occurs, the firing pin moves slightly upward as viewed in FIG. 4, breaking contact with the detonator boss 124 and providing the desired electrical indication that detonation has occurred. However, where such breaking of contact is not required, the construction of FIG. 7 is preferred, since it eliminates the possibility that the firing pin 116 may be propelled upward at high velocity out of the cartridge container upon detonation.
Thus in FIG. 7 the firing pin 116A is in the form of a metal rivet within an insulating bushing 118A, the head 130 of the rivet making contact with detonator boss 124. The bushing 118A is provided with a head portion 132 recessed in a counter-bore 134 in cartridge container part 90, and the head of the rivet overlaps the head of the bushing. Accordingly both bushing and rivet are restrained against blow-out from the cartridge container.
In the normal operation of the cartridge-actuated device shown in FIGS. 3-7, the device is assembled as shown and when a launch is to be made an electrical current is passed through contacting pin 50 to firing pin 116 to explode the cartridge 51. The hot propellant gases thereby formed are metered through the longitudinal and transverse orifices 80 and 82 in the orifice device 76 to launch the adjacent stores in the launch container, such as a sonobuoy for example.
However, should there be a blockage in the orifice device, the resultant abnormally high instantaneous internal pressures generated will tend to blow the inner and outer cylinders 90 and 96 apart. When this occurs, the frangible portion of the lower end of the inner cylinder 96 will break away, relieving the internal pressure and discharging parts of the cartridge-actuated device only downstream, in the launch direction, and not in the upstream or breech-end direction where damage to adjacent personnel and equipment might occur.
Furthermore, because of the use of the gas-sealing means in the form of O-ring 112, or 112a, the gases at high internal pressure created by explosion of the cartridge during abnormal operation cannot reach the threads 98 joining the inner and outer cylinders 90 and 96, and hence cannot weaken or fuse these threads in a manner which would permit their ready disengagement and resultant blowing apart of the inner and outer cylinder. Importantly, even if these threads should be weakened and the container should be blown apart, the secure holding of the upstream outer cylinder 90 by the breech cap 26 will prevent cylinder 90 from being propelled towards the breech end where personnel and equipment might be damaged, permitting only the possiblity of the inner cylinder 96 being propelled toward the muzzle-end of the launch container, without harm to personnel or equipment.
I have also determined that Where hot gases are prevented from flowing between the inner and outer cylinders during an abnormal operation with the gasreleasing orifice blocked, the inner cylinder will be heated first, will expand more than the outer cylinder, and will thereby cause the small opening betweeen inner and outer cylinders to close tightly, locking the two cylinders together and producing a stronger assembly to resist blowing apart of the entire cartridge container.
In addition, prior to insertion of the cartridgeactuated device in the launch position shown with the contact pin 50 in contact with the firing pin 1 16, the recessing of the firing pin below the outer surface of the metal-walled depression by a distance of at least about one-half the diameter of the depression greatly reduces the chances that a chance electrical discharge, due for example to static electricity, may pass into the cylindrical depression 140 and reach the firing pin 116 so as to explode the cartridge. This is because the metal walls of the depression will be closer to any entering spark discharge than is the firing pin 116, with the result that the discharge will normally occur to the walls of the depression, which are essentially grounded in the construction shown, rather than passing to the detonator and actuating the cartridge. Accordingly, harmful chance explosions of the cartridge actuated device during storage or transportation are substantially eliminated. It will be understood that the depression need not be cylindrical, so long as the top of the firing pin is recessed by at least about one-half the average diameter of the depression.
Using the cartridge-actuated device of the invention, it has been found that the above-described primary sources of hazard due to explosion of the cartridge during complete or partial blocking of the gas-releasing orifice are greatly mitigated. Although preferably all of the features of the invention are used in the cartridgeactuated device, some advantage is obtained by using less than all of these features. The cartridge-actuated device may be used to launch any of a variety of stores such as flares, propaganda materials, etc.
While the invention has been described with particular reference to specific embodiments thereof in the interest of complete definiteness, it will be understood that it may be embodied in a variety of forms diverse from those specifically shown and described, without departing from the spirit and scope of the invention as defined by the appended claims.
What is claimed is:
1. In a cartridge-actuated device for releasing explosively-propelled gas through gas-releasing means located at one end thereof in response to electrical detonation of an explosive cartridge in said device to launch military stores from an aircraft, wherein said device comprises: a multipart container containing said cartridge and intended to maintain its structural integrity upon actuation of said cartridge; an electrical contact exposed to the exterior of said container within a depression at the opposite end of said container from said gas-releasing means, and responsive to an electric current supplied thereto to detonate said cartridge; said container comprising a first part extending integrally about said opposite end of said device adjacent said contact, and a second part threadedly secured to said first part and extending about said one end of said device and supporting said gas-releasing means; and
means for securing said container to a mounting strucresistant gas-sealing means positioned to prevent ture without substantial external breech support of said gas under high pressure in said container adjacent device against forces generated by actuation of said said cartridge from flowing between the threads cartridge; the improvement according to which: holding together said first and second parts of said said means for securing said container to said mountcontainer.
ing structure comprises mounting means on said 2. The device of claim 1, in which said first part of first part of said container for securely mounting said container comprises a first generally-cylindrical said first part to said mounting structure during a metal shell with interior threads thereon and said secnormal operation thereof, and during an abnormal 0nd part comprises a second generally-cylindrical operation thereof in which said cartridge is aetumetal shell having exterior threads mating with said inated when said gas-releasing means is not fully opterior threads, said mounting means comprising exteerative; a portion of said second part of said conrior threads on said first shell.. tainer is frangible to burst and relieve pressure in 3. The device of claim 1, in which said frangible porsaid container before other parts thereof burst durtion comprises weakened regions in a wall of said secing said abnormal operation; and the walls of said 0nd part of said container adjacent said gas-releasing depression are of metal and said contact is recessed means. below the top of said depression by a distance at 4. The device of claim 1, in which said gas-sealing least about one-half the average diameter of said means comprises an O-ring of resilient material. depression; said device also comprising pressure-