US3065694A - Explosive train arming device - Google Patents

Description

Nov. 27, 1962 Filed De c. 15, 1955 D. A. PLANK EXPLOSIVE TRAIN ARMING DEVICE 2 Sheets-Sheet 1 INVENTOR DICK A. PLANK ATTORNEY Nov. 27, 1962 D. A. PLANK 3,065,694

EXPLOSIVE TRAIN ARMING DEVICE Filed Dec. 13, 1955 2 Sheets-Sheet 2 FICA.

INVENTOR DICK A. PLANK BY ATTORN YJ' United States latent Gfifice assess-4f Patented Nov. 27, 1%62 The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to arming devices for ordnance explosive trains and more particularly to an arming system wherein a means is provided for changing the medium separating the various vital components of a primer-detonatorabooster system in order to accomplish the arming operation.

At the present time, primer-detonator-booster trains in underwater ordnance utilize the principle of adequate physical separation of the Various components in air to prevent ultimate detonation of the booster. Components so separated are in a safe condition since shock caused by the detonator is attenuated by traveling through air with the result that it is too weak to cause initiation of the booster charge. To arm such a system, mechanism must be provided to mechanically move the detonator into the critical range where complete detonation will be possible upon firing actuation of the mine or other ordnance device. This arrangement, by its very nature, results in relatively complex mechanical devices inherently subject to malfunctioning,

damage, or improper adjustment. There are indications that certain failures in underwater ordnance are attributable to faulty extender functioning. In order to function properly these complex extender mechanisms must of necessity be in perfect working order. This is difficult to insure in view of the fact that such mechanisms are susceptible to damage from handling and from launching shock. Furthermore, the mechanism components are susceptible to a certain amount of deterioration in storage and this contributes to the possibility of malfunctioning. Also many detonator extender mechanisms used in underwater ordnance are dependent upon water pressure for their operation. This presents serious operational limitations when use in shallow waters is required. The uncertainty of operation coupled with the hazard of accidental arming by improper final assembly leaves much'to be desired in the arming systems now in use.

In general the present invention utilizes the principle that shock waves are conducted more efficiently by a liquid medium such as water than by a gas medium such as air. In employing this principle of difference of eiiiciency in the transmission of energy the present invention provides for a fixed distance of separation between the donor charge (detonator) and the acceptor charge (booster). This distance is so designed as to prevent detonation of the booster when the separating medium is air or other gaseous material. However, in this invention, there is provided means whereby the air separating these two vital components of the explosive train may be displaced by a liquid medium such as water. Once this is accomplished the explosive train is positively armed due to the ability of the liquid medium to permit propogation of the detonating energies with suflicient force to activate the acceptor charge. Means is also provided to reverse the above procedure whereby the arming liquid medium may be drained from the space separating the donor and acceptor charges in which event the explosive train is again rendered safe. The time involved in changing the medium separating the components may be controlled, as will later be more fully described,

so that positive arming of the ordnance device can be appropriately delayed to insure safety of the launching vessel. Furthermore it will be apparent that the mere presence of water in sufficient quantity to fill the detonator chamber will cause arming regardless of the depth of the water in which the ordnance device is placed.

The simple exchange of water for air within the detonator chamber eliminates the necessity of complicated detonator extender mechanisms and provides an arming system which is both reliable and safe.

An object of the present invention is the provision of an arming system in which the changing of the character of the separating medium between the various vital components of an explosive train will change it from a safe to an armed condition.

Another object is to provide an explosive train arming mechanism in which the arming function is completely independent of the water depth of submersion of the parent mine or other underwater ordnance device.

A further object of the invention is the provision of an arming device which eifects the sterilization of a mine or other ordnance by the mere draining oif of the liquid medium separating the components of its explosive train.

Still another object is to provide a new and improved means for arming an ordnance explosive train in which there is adequate time delay in completing the arming operation to insure safety to the launching vessel.

A still further object of the invention is to provide an arming device which is sufficiently rugged to prevent damage during handling or launching and which may not be accidentally armed by improper assembly.

Still other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view of an arming system constructed in accordance with my invention;

FIG. 2 is a sectional view of a modification of the invention illustrating a system in which the arming liquid is contained wholly within the system;

FIG. 3 is a sectional view of a floating moored mine incorporating a modification of the invention;

FIG. 4 is a fragmentary sectional view showing a modification of the invention as applied to projectiletype ordnance, the arming mechanism being in the safe position; and

FIG. 5 is a fragmentary sectional view similar to FIG. 4 showing the device in the armed position.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a portion of a mine or other ordnance weapon having a casing 10 which houses a main charge 11. The periphery of casing 16 has an opening therein to permit the insertion of a detonator-booster housing 12. to a position where it will be surrounded by the main charge. Housing 12 may be of any appropriate configuration but for the purpose of illustration the housing is shown as having a cylindrical hollow center portion 13 having an outwardly extending annular flange 14 which in turn has a stepped outwardly extending annular flange 15 projecting therefrom. Flange 15 may be bolted or secured in any appropriate manner to a recess presented by an inwardly extending annular flange 16 formed in the casing 16.

The housing 12 has a base plate 17 in which is located a centrally disposed opening 18 surrounded by an internally threaded boss 19 located on the inner face of the base plate. Boss 19 is adapted to receive an externally threaded connector member 20 to which is secured the detonator component 21 of the explosive train. Where appropriate connector 20 will also contain a sensitive primer element to actuate the detonator. Thus the detonator is secured within the interior of the housing 12 in a position substantially coaxial with the housing. Appropriate electrical leads 22 connect the detonator or the intermediate primer when used, with the usual firing mechanism such, for example, as the firing mechanism 69 of FIG. 3. This causes electrical detonation of the detonator when the firing mechanism is actuated. The lead wires are separated from the main charge 11 by means of an appropriate conduit such as the hollow tubing 23 secured to the lower face of base plate 17.

In accordance with the principle of the present invention a booster charge 24 is fixed in spaced relation with the primer-detonator component 21. In the embodiment shown in FIG. 1 of the drawings the booster is of a hollow cylindrical shape and is so located as to be substantially coaxial with the detonator and having its inner surface in spaced relation thereto at a distance predetermined in accordance with the composition of both the detonator and booster charges. The booster charge 24 is housed in a container 25 adapted to fit the interior of the detonator-booster housing 12 and having inner and outer cylindrical walls 26 and 27 connected by a transverse portion 23. The outer face of connecting plate 28 is provided with a plurality of protuberances 28' so as to space the booster container from the base plate 17 of the housing in order to permit flow of liquid between the two plates as will hereinafter be more fully described. The diameter of the inner face of wall 26 is slightly greater than that of boss 19 to also permit flow of liquid between these two members.

As will be seen in FIG. 1 the inner wall 26 forms in 'eifect a detonator chamber designated as 29. Inner wall 26 extends longitudinally outward a greater distance than does outer wall 27 and at its outermost end is internally threaded. The outer portion of the detonator chamber is covered by a circular orifice plate 30 which rests on an abutment shoulder 31 formed on the inner surface of wall 26. Adjacent orifice plate 30 lies a circular soluble disc 32 held in place by an externally threaded circular cap member 33. Cap 33 may be constructed of plastic or other suitable material and contains a plurality of orifices 34. These orifices and the orifices 35 located in plate 30 are so designed as to permit a predetermined rate of flow of liquid from the exterior of the casing 10 to the interior of the detonator chamber 29. Various arrangements could be made to insure against premature entrance of liquid into the detonator chamber during storage and handling. For example a water impervious cap could be placed over the end of cylindrical wall 27 and removed when the ordnance is ready for use. Also a protective impervious disc could be placed between cap 33 and the soluble disc until ready for use and removed prior to launching.

Referring to FIG. 1 it will be seen that booster container 25 is retained within the housing 12 by means of a cover plate 36. This plate is provided with a central aperture 37 through which extends the cylindrical center portion of the booster container. The cover plate is secured in place by means of bolts 38 or the like which threadingly engage annular flange 14 of the detonatorbooster housing 12.

In order to permit proper drainage of water from the detonator chamber upon recovery of the ordnance device from the water and to also permit flooding of the detonator chamber should the openings provided in cap 33 be buried in the mud, the present system includes at least two auxiliary vents. These vents connect the detonator chamber with the exterior of casing 10 through openings 39 positioned at approximately 120 on either side of the cap 33 and in this manner the casing is provided with independent venting means disbursed about the periphery thereof.

In construction, the auxiliary vents comprise a conducting pipe ti secured in any suitable manner to the detonator-booster housing 12 and a boss 42 secured to the inner face of the casing. Cavity 41 formed with the boss contains liquid flow control elements similar to those located in the outer portion of the detonator chamber. These elements consist of an orifice plate 43, a soluble disc 44 and an externally threaded cap 45 having a plurality of orifices located therethrough.

An explosive train incorporating the present invention remains in an inert or safe condition during storage and handling due to the fact that a selected gaseous substance such as air initially fills the detonator chamber thereby separating the detonator 21 from the booster charge 24. The size of this air gap and the thickness of Wall 26 are so designed in accordance with specific explosive compounds to be used that should the detonator be prematurely activated the booster charge will not be set off due to the poor shock transmitting characteristic of air.

When the ordnance device is launched into a body of Water the orifices located in cap 33 will permit the entrance of water to the soluble disc. In time the disc will dissolve permitting entrance of Water into the detonator chamber 29 by way of the orifices in plate 36 Due to the fact that fluids can transmit higher detonating energies for given distances than can gaseous material, shock waves created by the explosion of the detonator will be transmitted in sufficient force to cause the explosion of the booster charge which in turn activates the main charge to accomplish complete explosion of the ordnance device.

In FIG. 2 there is shown a modified embodiment of. the invention wherein the mine or other ordnance device is provided with an appropriate liquid reservoir and pumping system which will effect the mechanical change of shock transmitting medium located in the detonator chamber. In this embodiment the booster container 46 is surrounded by the main charge 47 and appropriately retained by means of a cover plate 48 secured to a mine casing 49 by bolts 50 or other appropriate fastening means. Plate 48 has secured through an opening therein a threaded coupling 51 which retains the primer-detonator element 52 in a central position substantially coaxial with the cylindrical detonator chamber 53 formed by the inner wall 54 of the booster container. Lead wires 55 connect the primer-detonator with a conventional electrical firing mechanism means such as the firing mechanism 59, FIG. 3. A booster charge 56 is contained between the coaxial inner and outer walls of the booster container.

The base of the booster container is provided with a pair of openings in communication with chamber 53 to which are respectively secured conduits 57 and 58. In a normal position of a moored mine, conduit 57 connects the upper portion of chamber 53 with the upper portion of a reservoir 59 which contains a copious supply of liquid medium such as light oil or water and conduit 58 completes a fiuid connection between the lower part of chamber 53 by way of a pump to the lower portion of reservoir 59. A conduit 69 leads from the lower portion of reservoir 59 and connects with conduit 58 through a conventional two-way pump shown schematically at 61.

A clock device 61a or other appropriate means can be utilized to activate pump 61 whereby liquid from reservoir 59 can be forced into the detonator chamber causing the gaseous or air medium originally contained therein to be evacuated through conduit 57. Thus with the liquid medium filling the space in chamber 53 between detonator 52 and the booster charge 56 the explosive train is in an armed condition. While a simple flow circulation system has been shown for the purpose of illustration other conventional systems employing liquid-air discriminating valves and the like may be used.

This form of the invention has the advantage of permitting mechanical sterilization of the explosive train. To achieve this result a clock device 61a or other means aoeaee t may be utilized to actuate pump 61 in a reverse direction whereby the liquid medium will be exhausted from the detonator chamber 53 and the explosive train thus rendered in a safe or unarmed condition.

On FIG. 3 of the drawings is shown the principle involved in the present invention as applied to a moored mine. For purposes of illustration I have shown the mine as comprising a spherical casing 62 having extending therefrom a plurality of firing horns 63 for actuation of the mine upon impact. The mine casing has an appropriate mooring fixture 64 to enable the mine to be held at a predetermined position below the surface of the water by a mooring cable (not shown) affixed thereto. The interior of the mine comprises a main charge 65, a main booster charge 66 and initiating booster 67, a primer-detonator element 68 and a conventional firing mechanism 69. The detonator-booster housing 76 is located in the upper portion of the mine and secured to the casing thereof by bolts 71 or other appropriate fastening means. In to this housing is placed the initiating booster container 72 which is held in place by a retaining plate 73 which in turn is bolted to the housing. The inner cylindrical wall 74 forms a detonator chamber 75 which is defined at its outer end by an orifice plate 76 having openings therein. A soluble disc 77 and a threaded retaining cap 78 having openings therein are located outwardly of the orifice plate.

Detonator 68 is secured to the base plate 7% of the booster-detonator housing by means of a threaded coupling 39 which also connects the detonator and appropriate feed wires 81 which in turn connects with the firing mechanism 69. Firing mechanism 69 is connected to each of the firing horns 63 as shown.

An important feature of this modification is the inclu sion of a plurality of detonator chamber vents which connect the chamber 75 with the exterior of the mine casing. Base plate 79 is provided with an opening 82 therethrough for each of such vents. An appropriate tubing 83 extends through each opening from the detonating chamber 75 to a vent opening provided in the surface of the mine casing. As shown in FIG. 3 each vent opening has associated therewith an appropriate soluble disc 84 located between an orifice plate 85 and a cap member 86 also having orifices therein.

In operation this modification of the invention is armed in a manner similar to that described in connection with FIG. 1 of the drawings. When the mine is immersed in water the liquid enters through the apertures in retaining cap 78 and also in the various cap members 86 covering the vents. In due time the presence of the water attacks the soluble Washers which when dissolved permit the entry of water into the detonator chamber Thus with this medium having high efficiency for transmission of shock energy the initiating booster charge 67 will be detonated upon explosion of the detonator member 68. A distinct advantage of the use of my invention in the moored type of mine lies in the fact that the mine is rendered safe once it breaks free from its mooring and becomes free floating as shown in FIG. 3. As will be seen from FIG. 3, in the free-floating condition of the mine the detonator chamber rides above the normal water line and thus through the use of vents as shown the chamber is automatically drained of water. This positively disarms the mine. This arrangement is decidely advantageous over the present type of disarming device, namely the extender mechanism, since the latter is readily corroded when exposed to sea water for an extended period and cannot always be relied upon to function properly.

FIG. 4 of the drawings illustrates the application of the invention to rocket or gun-projectile type ordnance. The device as shown in FIG. 4 is in the safe position and is adapted to a projectile having a body 87 which carries a nose assembly 83 in which is located a conventional type nose fuze (not shown). The forward portion of body 87 is internally threaded at 89 to receive a booster detonator housing generally indicated at 90. This housing is so positioned as to permit'the main charge 91 of the projectile to substantially surround the housing. The forward portion of housing is bifurcated having an inner cylindrical wall 92 and an outer cylindrical Wall 93. These walls define an annular recess 94 which serves as a container for booster charge 95. The interior of housing 90 comprises an elongated chamber 96 closed at one end by the end Wall 97 and at its opposite end by an externally threaded cap 98. This cap has a threaded central aperture 99 adapted to receive an externally threaded primer-detonator coupler 100. The coupler has extending from the forward face thereof a conventional primer device 101 which may be actuated when struck by a firing pin MP2 or the like of the fuze mechanism. A detonator 103 extends rearwardly of coupler wt) and is positioned coaxially with chamber 96.

As seen in FIG. 4 a piston-like sliding safety block 104 is located Within chamber 96 and in the safe position is adapted to surround detonator 103 thus effectively separating the detonator and the booster charge by a mass of shock absorbing material. Block 104 is preferably made of soft steel or other material having poor shock transmitting characteristic. The rear face of the block is formed with a circular recess 105 within which is secured a spring 106 for normally maintaining the block 104 in the safe position. In response to a sustained acceleration of a predetermined magnitude, a rearward movement will be imparted to block 104 whereupon the liquid disposed in the after chamber will be transmitted through apertures 167 into the forward or arming chamber. The size and number of the apertures may be so designed as to permit the exchange of the liquid medium for the solid medium within the time limitations of sustained acceleration. Once the sliding safety block has been moved and retained in the after chamber the liquid medium completely surrounds the detonator thus arming the explosive train, as shown in FIG. 5. The time factor required in the arming cycle will prevent premature arming of the train due to accidental dropping of the round. Obviously the time of deceleration caused in dropping would be too short an interval to allow any appreciable quantity of liquid to be transferred. Also the same safety advantage would apply if the round struck an object such as the edge of a barricade or limb of an over-hanging tree which might be too close to the launcher or gun. Furthermore once the safety block has been fully retracted the snap ring device 108 engages the forward collar of an annular groove 109 formed in housing 90 which prevents the block from later returning and disarming the train. This is an improvement over the use of the rotating principle for arming gun projectiles since the latter begin to fail at extreme ranges or when the gun rifling begins to appreciably wear and fails to give the round a sufiiciently high rate of initial rotation.

From the foregoing description it is apparent that a means has been provided whereby the shock transmitting medium which exists between the various vital components of a primer-detonattor-booster system may be changed in character to arm or disarm an ordnance device without the necessity of providing a mechanical means for bringing the components closer together for this purpose. This simple and positive arming operation utilizes the fact that different materials have different degrees of effectiveness in transmitting shock wave energies from a detonator to a booster charge spaced therefrom. Thus the simple exchange of shock transmitting medium obviates difficulties presented by complex mechanical extended mechanisms, simplifies the design of certain types of underwater 0rdnance, and insures positive arming of an explosive train irrespective of the depth of water in which the ordnance device is launched,

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within 7 the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed a new and desired to be secured by Letters Patent of the United States is:

1. In an explosive train arming means the combination of a body member, said body having a chamber therein, a donor charge supported in said chamber in spaced relation to the sides thereof, an acceptor charge surrounding said chamber in part, said donor charge and acceptor charge being so spaced as to render shock waves caused by explosion of said donor charge ineffective to cause explosion of said acceptor charge when the chamber is filled with air, and means for introducing a liquid into said chamber to increase the shock transmission to the acceptor charge upon explosition of the donor charge.

2. In an explosive train the combination of a body member, a detonator, means for exploding said detonator, a booster charge spaced from said detonator, said body member having a chamber therein within which said detonator and said booster charge are disposed, said chamber being normally substantially filled with a medium characterized by sufiiciently poor shock-transmitting quality to prevent ignition of said booster charge by the explosion of the detonator, and means for replacing said medium with a second medium having a better shocktransmission characteristic whereby shock waves caused by explosion of said detonator will explode the booster charge.

3. The invention as set forth in claim 2, wherein the first said medium is a gaseous substance.

4. The invention as set forth in claim 2 wherein said second medium is a liquid.

5. The invention as set forth in claim 2 wherein the first said medium is a gaseous substance and said second medium is a liquid,

6. In an explosive train the combination of a body member, a detonator, means for exploding said detonator, a booster charge spaced from said detonator, said body iiiember' having a chamber therein within which said detonator and said booster charge are disposed, said chamber being normally substantially filled with a medium characterized by poor shock-transmitting quality, means connecting said chamber with a liquid supply and means for introducing said liquid into said chamber to increase shock-transmission to the booster charge upon explosion of the detonator.

7. The invention as set forth in claim 6 wherein said means for introducing liquid comprises an apertured plate initially sealed by a soluble disc.

8. The invention as set forth in claim 6 wherein said means for introducing said liquid includes a pump and means for actuating said pump.

9. The invention as set forth in claim 6 wherein the first said medium consists of a sliding block adapted to be moved from an initial position between said detonator and booster, said block having apertures therein for introducing liquid into said chamber upon movement of the block.

10. In an explosive train arming means for use in an underwater ordnance device the combination of a casing having a main charge therein, a booster charge in proximity with said main charge, a detonator in spaced relation with said booster charge, said space between the detonator and booster charge comprising a chamber adapted to be filled with a gaseous substance in the unarmed condition of the explosive train, said casing having an opening therein connecting said chamber with the exterior of the ordnance device, a soluble disc arranged transverse of said opening, apertured retaining means for said disc, said disc being adapted to dissolve upon immersion in water to permit entry of Water into said chamber, and means for actuating said detonator.

11. The invention as set forth in claim 10 wherein said 8 casing is provided with BUXlllZll'Y means for connecting said chamber with the exterior of the casing, said auxiliary connecting means having a soluble disc therein adapted to dissolve when submerged in water.

12. An ordnance explosive train comprising a booster charge, a detonator in spaced relation with said booster charge, the space between the detonator and booster charge comprising a chamber adapted to be filled with a gaseous substance in the unarmed condition of the explosive train, a liquid reservoir, conduit means connecting said chamber with said reservoir, a pump located in said conduit means and adapted to transfer liquid from said reservoir to said chamber, and means for actuating said detonator.

13. The invention as set forth in claim 12 wherein said pump is reversible to withdraw liquid from said chamber thereby to disarm the explosive train.

14. In an explosive train arming means for use in an underwater ordnance device, the combination of a casing having a mean charge therein, a booster charge in proximity with said main charge, a detonator in spaced relation with said booster charge, the space between the detonator and booster charge comprising a chamber adapted to be filled with a gaseous substance in the unarmed condition of the explosive train, said casing having an opening therein connecting said chamber with the exterior of the ordnance device, a soluble disc arranged transverse of said opening, apertured retaining means for said disc, said disc being adapted to dissolve upon immersion in water to permit entry of water into said chamber, means for actuating said detonator, drain means connecting said chamber with the exterior of said casing, said drain means being located below the plane of said chamber, and a soluble disc located in said drain means.

15. In an explosive train arming device for projectiles, the combination of a casing, a booster charge within said casing, a detonator in spaced relation to said booster charge, the space between the detonator and booster charge comprising the forward portion of a chamber, said chamber extending rearwardly of the detonator and booster charge, a slidable piston within said chamber, said piston being composed of a material having poor shocktransmission characteristic, spring means for normally holding said piston in the forward portion of said chamber intermediate said detonator and booster charge, a quantity of liquid located in the rearward portion of said chamber, said piston having longitudinal apertures therein to permit said liquid to flow to the forward portion of said chamber upon rearward movement of said piston, means for locking said piston in its rearward position, and means for actuating said detonator.

16. An explosive train arming means comprising a body member having a donor charge and an acceptor charge therein, said charges being in spaced relation to one another, a separating medium located in the space between said charges, said medium being a substance having a poor shock-transmission characteristic, and means for replacing said medium with a liquid medium having better shock-transmission characteristic.

17. An explosive train arming means comprising a body member having a donor charge and an acceptor charge therein, said charges being in spaced relation to one another, a gaseous medium having a poor shocktransmission characteristic located in the space between said charges, and means for replacing said gaseous medium with a liquid medium having better shock-transmission characteristic.

References (listed in the file of this patent UNITED STATES PATENTS 1,751,616 Brayton Mar. 25, 1930

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