US3709148A

US3709148A - Drill mine

Info

Publication number: US3709148A
Application number: US00130141A
Authority: US
Inventors: V Costley; S Wolf
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1971-04-01
Filing date: 1971-04-01
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

A drill mine, having the same operational and physical characteristics as a service mine is provided with apparatus for indicating mine actuation and for providing retrieval thereof. A buoyant float assembly is provided which shortly after water entry separates from the drill mine body but remains tethered thereto. Upon mine actuation a smoke generating signal float is released from the float assembly and rises to the surface thereby giving an indication of mine actuation. After a preset time, the float assembly is released from its tethered mode and floats to the surface carrying a recovery line therewith. Upon surfacing, recovery personnel may use the recovery line to remove a heavy retrieval line stored and fixed within the mine case. The retrieval line is employed to pull the mine from the bottom onto a recovery vessel.

Description

Unite States Patent 1191 Costley et a1.

[ 1 Jan. 9, 1973 54] DRILL MINE Inventors: vivian fif fiostley, kensington iiigfitsjfiaffs' ivih Wolf, Silver Spring, Md.

[73] Assignee: The United States of America as represented by the Secretary of the Navy 22 P111511? A hirl 1113571 [21] Appl. No.: 130,141

[52] U.S. Cl. ..l02/10, 102/13 [51] Int. Cl ..F42b 22/00 [58] Field of Search ..102/10,l3,14

[56] References Cited UNITED STATES PATENTS 2,775,939 1/1957 Fogal ..l02/13 2,813,486 11/1957 Goth... 2,949,853 8/1960 Vogt..... 3,017,831 1/1962 Barry 4/1963 Butler et al ....102/l0 Primary Examiner-Samuel W. Engle Attorney-R. S. Sciascia, J. A. Cooke, R. J. Erickson and M. G. Raskin [57] ABSTRACT A drill mine, having the same operational and physical characteristics as a service mine is provided with apparatus for indicating mine actuation and for providing retrieval thereof. A buoyant float assembly is provided which shortly after water entry separates from the drill mine body but remains tethered thereto.

Upon mine actuation a smoke generating signal float is released from the float assembly and rises to the surface thereby giving an indication of mine actuation. After a preset time, the float assembly is released from its tethered mode and floats to the surface carrying a recovery line therewith. Upon surfacing, recovery personnel may use the recovery line to remove a heavy retrieval line stored and fixed within the mine case. The retrieval line is employed to pull the mine from the bottom onto a recovery vessel.

5 Claims, 5 Drawing Figures- PAIENTEfim '9 m3 3.709.148

INVENTORS Vivian G. Costley ylvan Wolf BY 7 iZwfl/ ATTORNEY HQJZMCT 405m DRILL MINE BACKGROUND OF THE INVENTION This invention relates generally to drill mine apparatus and more particularly to a realistically configured drill mine which provides a visual signal indicative of mine actuation and further provides for retrieval of the drill mine.

In the past, drill mines have been used in orderto provide operational training devices for personnel who normally would operate the actual service mine counterparts. In previous air launched bottom drill mines, an extension section was provided between the tail of the mine case and the disposable flight gear to house the mine actuation signal and recovery equipment. The

rn ine case explosive compartment is usually filledwith inert material. The extension section with the signal and recovery equipment appreciably changed the length, weight and center of gravity of the mine. It further altered its handling and loading characteristics aboard the launching aircraft and often decreased the number of drill mines that could be carried relative to service mines. Further, the changed physical characteristics caused the maximum planting speed, the ballistic characteristics and the underwater trajectory to differ from the service mine. Other problems inherent in drill mines having extended drill sections provided at the ends thereof include necessitating the use of a different type of parachute pack and release mechanism and fairing than employed on the service mine. All of these changes affect the realism of the drill mines thereby greatly reducing their training value.

The mine actuation signal mentioned hereinabove indicates when the drill mine is actuated during tests and usually take the form of buoyant smoke and flame producing float devices releasably connected to the mine case. Upon actuation of the mine by the passage of a target ship or the like, these float devices may be released thereby rising to the surface to provide a visual indication of mine actuation. The conventional drill mines as described hereinabove create a number of difficulties, however. It has not been uncommon for a test mine upon reaching the floor of the body of water to become buried in the soft, muddy surface thereof. When this occurred, frequently, the float was prevented from releasing itself from the mine body due to the muddy environment. In these cases, for all intents and purposes, the mine served no further use. Still another problem was inherent in the prior recovery procedures used in drill mine operations. In the past, divers were necessarily employed in order to accomplish retrieval of the mine, often entailing a great expenditure of time between test runs.

SUMMARY OF THE INVENTION Accordingly, one object of this invention is to provide a new and improved drill mine having the same physical and operational characteristics as its service mine counterpart.

Another object of the invention is the provision of a new and improved drill mine including apparatus for providing visual signals indicative of mine actuation.

A further object of the instant invention is to provide a new and improved float assembly which separates from the drill mine prior to the mine settling on the bottom of the body of water.

A still further object of this invention is the provision of a new and improved system for facilitating and effecting retrieval of the drill mine from a surface ship without the use of divers.

Briefly, in accordance with one embodiment of this invention, these and other objects are attained by providing in a portion of a drill mine having an identical configuration to its service mine counterpart, a positively buoyant float assembly adapted to be expelled from the drill mine shortly after water entry. The float assembly is tethered to the drill mine and remains suspended a relatively short distance thereabove as the mine descends and finally settles to the bottom of the sea. The float assembly is provided with a buoyant signal float and a primary recovery line. The primary "recovery line is connected at its end to a recovery cable stored in another part of the drill mine body. Upon mine actuation, the signal float is expelled from the float assembly and rises, entirely free from the drill mine body, to the surface where suitable visual displays are caused to occur, thereby indicating the actuation of the mine. The tethering line connecting the float assembly to the drill mine is caused to be severed by one ofa number of possible methods such, for example, as a timer actuated cutting device. The float assembly then rises to the surface paying out the primary recovery line stored therein. Upon reaching the surface, personnel on the recovery ship may, by grasping and withdrawing the primary recovery line, thereby extricate the recovery cable. The recovery cable is of sufficient strength to enable the drill mine to be lifted from the bottom.

BRIEF DESCRIPTION OF THE DRAWING A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a side elevation view in partial section of the drill mine according to the present invention;

FIG. 2 is a plan view taken along line 2-2 of FIG. 1 showing the tethered connection between the float assembly and the drill mine;

FIG. 3 is a side elevation view in section of the recovery cable storage compartment as seen along line 33 of FIG. 1;

FIG. 4 is an elevation view of the drill mine and the float device in the tethered mode, with the drill mine being shown in transverse section; and

FIG. 5 is a side elevation view in section of the timer (shown symbolically) storage well as seen along line 5-5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, wherein a drill mine 10 is formed of a substantially cylindrical metallic case 12 whose exterior dimensions are nearly identical to the service mine configuration. A ballast weight 13 may be strategically positioned within the case 12 to provide the drill mine with similar physical characteristics, such as the center of gravity, to its service mine counterpart. A cylindrical cavity 14 is formed in the forward portion of the drill mine case transverse to the longitudinal axis thereof. The cylindrical cavity 14 provides a housing for a float assembly 16 which is releasably fastened thereinby retaining screws 74 (FIG. 2) designed to rupture upon application of a large impulse type force.

The float assembly 16 includes a housing 17 formed of a suitable metallic material such, for example, as aluminum, and is of a generally cylindrical shape. A first float compartment 18 and a second cylindrical float compartment 20 are defined with the housing 17. The first float compartment 18 has positioned therein a substantially cylindrical recovery line container 24 which itself is divided into upper and

lower portions

26 and 28 by a horizontal separating wall 30. The lower portion 28 of the recovery line container 24 provides a housing for a relatively short length of heavy tubular braided nylon line 42. The heavy line 42 passes through a pair of lugs 44 fixed to the bottom of the float assembly housing 17 as best seen in FIG. 2. The heavy line 42 further passes through an opening 45 formed in an explosive cutting device 46, which will be described in greater detail hereinafter, permanently fixed to the drill mine case 12. The heavy line 42 is spliced togetherat its ends 47 and forms a continuous loop as may be seen in FIG. 4.

The upper portion 26 of recovery line container 24 houses a substantial length of nylon recovery line 48. One end of the nylon recovery line 48 is fixed to the recovery line container 24 by pin 50 in a reduced diameter cylindrical portion 27 integral with the upper portion 26 thereof. The recovery line 48 passes through an opening (not shown) in the separating wall 30, through the lower portion 28, and exits from the float assembly 16 through a pair of

circular openings

52 and 54 formed in the lowermost wall of recovery line container 24 and float assembly housing 17, respectively. The other end of recovery line 48 is connected at 53 to one end of a steel wire rope recovery line 57. The major portion of the length of the steel rope 57 is housed in a transverse cylindrical bore 56 formed behind the cylindrical cavity 14. The bore 56 is closed to the external environment by cover member 58 which is fastened by conventional means such, for example, as bolts 60 to the outer drill mine case 12. A gland fitting 62 is provided at the inner portion of cylindrical bore 56 and cooperates with a length of water resistant tubing 55 to lead in the end portion of steel rope 57 which is fastened to the nylon recovery line 48 and further to prevent leakage of water into the mine from the bore 56 which becomes filled with water upon water entry. The second end of the steel rope 57 is fixed to the mine case 12 at lug 49.

The second float compartment 20 contains a conventional buoyant signal float 32 which may be of a type such that, upon the rupturing of the outer metallic skin thereof and the consequent entry of seawater therein, a chemical reaction occurs with a resulting production of vast quantities of smoke and flame. The second float compartment 20 is closed at the top by a cover member 34 having an O-ring 36 positioned therearound which provides a fluid seal between the external environment and the inside of the second float compartment. The

lower end of float portion 20 is closed by second cover member 38 which is affixed to float portion 20 by conventional means, such for example, as by welding.

Cooperating with the second float compartment 20 through the cover member 38 is an explosive fitting 64 which itself is connected by an electrical cable 66 to a mine fire control system (not shown) of a conventional nature which emits an electrical impulse upon mine actuation, thereby causing initiation of the explosive fitting 64. The electric cable 66 also passes through the opening in explosive cutting device 46 nd is of sufficient length to reach the float assembly 16 when in its tethered mode (see FIG. 4).

The explosive cutting device 46 is of a conventional type and may comprise a knife edge adapted to move through the opening 45 upon initiation of an explosive charge. The cutting device is actuated by an explosive fitting 68 electrically coupled by way of electric cable 70 to a conventional actuation device such, for example, as a mechanical timer mechanism 71 (FIG. 5). In lieu of a timer mechanism, other apparatus, such for example, as a remote controlled device 73 may be used to provide an actuation signal to the explosive fitting 68. The actuation device is held in a well 72 substantially adjacent to bore 56 and is adapted to begin its ,7 timing sequence upon water entry of the drill mine. At

the completion of the timing sequence, an electrical impulse is generated by the timer mechanism which actuates the explosive fitting 68.

In operation, the drill mine 10 is launched in a conventional manner such as by an aircraft and a parachute may be employed to retard the mines velocity prior to water entrance. After entry, the mine is caused to become horizontally oriented due to its slant nose 80. Immediately subsequent to this turn, hydrodynamic forces act upon the drill mine case 12 as the water-air interface of the air pocket created by cavitation moves against the mine case. These impulse forces cause appropriately designed retaining screws 74 (FIG. 2) to rupture, at which time the buoyant float assembly 16 exits from the cylindrical cavity 14. The float assembly 16 attains a moored position as best seen in FIG. 4 suspended above the drill mine 10 by the heavy line 42. The drill mine subsequently comes to rest on the bottom of the body of water with the float device 16 suspended thereabove as described. The mine and float assembly retain this configuration until a suitable target acquisition is obtained at which time an impulse from the fire control system is transmitted by electric cable 66 to the explosive fitting 64 resulting in ignition thereof. The ignition of explosive fitting 64 causes the signal float 32 to be expelled from second float compartment 20. The cover member 34 has a projection 76 formed thereon which ruptures the wall of the signal float upon its expulsion enabling seawater to enter therein and thereby generate smoke. To enable the float to successfully exit from the second float compartment 20, a spring 78 provides an outwardly biased force which causes the float to successfully exit. It is thus seen that the signal float 32 rises to the surface of the water unencumbered by any tethering line and a visual signal of mine actuation is accomplished. While the signal float rises to the surface, the float assembly 16 remains tethered to the drill mine-I0 by the heavy line 42, as may be seen in FIG. 4. After a predetermined time, the timer mechanism housed in well 72 causes the explosive fitting 68 to be initiated by sending an electrical signal through cable 70. The initiation of this explosive device causes the cutting device 46 to sever the heavy line 42 and the electric cable 66 thereby allowing the float assembly 16 to rise to the surface, while paying out the nylon recovery line 48 between the float assembly 16 and the drill mine 10. The float assembly is recovered by a recovery vessel and the nylon recovery line 48 is used to withdraw the wire rope 57 from the cylindrical housing 56. The wire rope 54 is fixedly attached to the drill mine case at lug 49 and is used to lift the drill mine from the bottom.

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

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

l. A recoverable drill mine which simulates the operational and physical characteristics of a service mine counterpart comprising:

a mine case adapted to be launched from suitable launching means having a substantially identical shape to said service mine including a first cavity formed therein;

a second cavity formed in said mine case;

a first recovery line housed in said second cavity having one end fixed to said case;

a positively buoyant float assembly housed in a first position in said first cavity having a first comparb ment and a second compartment defined therein, said float assembly adapted to attain a second position upon said launching outside of said first cavifirst means for flexibly connecting said float assembly to said mine case, housed in said first compartment;

second means housed in said first compartment for flexibly connecting said float assembly to said first recovery line;

a fire control system positioned in said casing and responsive to the influence of a mine actuating source to produce a first electrical signal;

a positively buoyant signal flare positioned within said second compartment;

means electrically connected to said fire control system for expelling said signal flare from said second compartment in response to said first electrical signal;

means for severing said first flexible connecting means in response to a predetermined second electrical signal; and

means for generating said second predetermined signal.

2. A drill mine as recited in claim 1 wherein said means for severing the flexible connection between said float assembly and said mine case also severs the electrical connection between said flare expulsion means and said mine casing and includes an electroresponsive explosive cutting member.

3. A drill mine as recited in claim 2 wherein said means for generating said predetermined second electrical signa includes a timing mechanism adapted to begin a timing sequence upon water entry and continue with said timing sequence for a predetermined length of time thereafter, whereupon said predetermined second signal is generated.

4. A drill mine as recited in claim 2 wherein said means for generating said second predetermined signal includes signal generating means responsive to remote actuation from an external point.

5. A drill mine as recited in claim 3 wherein said first recovery line includes steel wire rope.

Claims

1. A recoverable drill mine which simulates the operational and physical characteristics of a service mine counterpart comprising: a mine case adapted to be launched from suitable laUnching means having a substantially identical shape to said service mine including a first cavity formed therein; a second cavity formed in said mine case; a first recovery line housed in said second cavity having one end fixed to said case; a positively buoyant float assembly housed in a first position in said first cavity having a first compartment and a second compartment defined therein, said float assembly adapted to attain a second position upon said launching outside of said first cavity; first means for flexibly connecting said float assembly to said mine case, housed in said first compartment; second means housed in said first compartment for flexibly connecting said float assembly to said first recovery line; a fire control system positioned in said casing and responsive to the influence of a mine actuating source to produce a first electrical signal; a positively buoyant signal flare positioned within said second compartment; means electrically connected to said fire control system for expelling said signal flare from said second compartment in response to said first electrical signal; means for severing said first flexible connecting means in response to a predetermined second electrical signal; and means for generating said second predetermined signal.

3. A drill mine as recited in claim 2 wherein said means for generating said predetermined second electrical signal includes a timing mechanism adapted to begin a timing sequence upon water entry and continue with said timing sequence for a predetermined length of time thereafter, whereupon said predetermined second signal is generated.