US3130384A

US3130384A - Artificial target

Info

Publication number: US3130384A
Application number: US657584A
Authority: US
Inventors: George W Downs; Raymond D Atchley
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-03-27
Filing date: 1946-03-27
Publication date: 1964-04-21
Anticipated expiration: 1981-04-21

Description

April 21, 1964 Filed March 27, 1946 h IF 'lll/111111111111111 G. W. DOWNS ETAL ARTIFICIAL TARGET IQ smuLAToR sEcTloN Nose sEcTioN 4 Sheets-Sheet l MAIN BODY GEORGE w. Downs RAYMOND n. ArcHLVEY www@ April 21, 1964 G. w. DowNs ETAL A 3,130,384

ARTIFICIAL TARGET Filed March 27, 1946 4 Sheets-Sheet 2 AFTERBODY gmc/rm GEORGE w. Downs RAYMONDV o. ATcHLEY April 21, 1964 G. w. DOWNS ETAL `ARTIl-"ICIAL TARGET 4 Sheets-Sheet 3 Filed March 27, 1946 FIG. 2

' INVENToRs GEORGE w. DOWNS RAYMOND D. ATCHLEY ATTORNEY April 21,1964 G. w. DOWNS EII'AL ARTIFICIAL TARGET 4 Sheets-Sheet 4 Filed March 27, 1946 INVENToRs'.

GEORGE W. DOWNS RAYMOND D. AT OHLEY a Attorney United States Patent Ofiice 3,130,384 Patented Apr. 21, 1964 3,136,384 ARTIFICIAL TARGET George W. Downs, Pasadena, and Raymond D. Atchley, San Diego, Calif., assignors to the United States of America as represented by the Secretary of the Navy Filed Mar. 27, 1946, Ser. No. 657,584 Claims. (Cl. 340-5) The present invention relates to the use of underwater sound in submarine warfare.

A surface ship employs underwater sound to hunt down submarines. It not only listens for the noise made by the propellers and gears of the submarine, but it also sends out pings, or short pulses of sound, so that the submarine will send back echoes. These sound-guided attacks are so effective that submariners often prefer to evade, rather than meet, them.

Objects of the present invention include the provision of a device for diverting anti-submarine attacks, the provision of a decoy that simulates the noises and sound characteristics of a submarine, the provision of a self propelled decoy capable of being launched from a submarine for facilitating an escape, and the provision of an improved practice target.

The target of the present invention is a small, self-propelled, torpedo-like submersible Craft, having automatic depth and course controls. It is adapted to be launched from the torpedo tube of a submerged submarine, and, after a short delay, to begin generating noises and repeating pings for simulating the self-noise and the soundreilecting characteristics of a submarine. In combat, a submarine may launch such a target to mislead an attacker and so facilitate its own escape. As a practice target the device may be used for training the crews of surface ships.

These and other objects and advantages of the present invention will be apparent from the following description of a specific embodiment of it. In the drawings:

FIG. l is an elevation, partly in section, of the device of the present invention.

FIG. 2 is an elevation, partly in section of a submarine torpedo tube with the device of the present invention installed ready for launching.

FIG. 3 is a schematic diagram of the electrical system of the present invention.

FIG. 4 is a diagrammatic representation of part of the mechanism.

In FIG. 1 the assembly of the present invention consists of a nose section 1d, simulator section 11, main body 12, and an after-body 13. These several units are joined with water tight seals and together they form a cylindrical unit 70 inches long and six inches in diameter. Projecting from the top and bottom of the after body 13 are

transducers

14 and 16 that are a part of the echo repeater equipment, which will be described presently. The overall height of the target at the transducers is slightly more than 20 inches, thus permitting the target to be released through a standard 21 inch torpedo tube. Anti-fouling cables 1S extending from the tip of each transducer to the nose section 11B prevent the transducers from catching on the submarine gear during the launching operation. Vertical stabilizer ns 20 and rudders 22 and similar horizontal controls (not shown) guide the target, and a propeller 5t) drives it.

The nose section is free flooding and contains a sea- `activated battery 24 which generates 24 volts D.C. This battery furnishes all the power for the target.

The simulator section 11 contains a simulator motor 26 and a gear train 28, which will be described presently. In the main body 12 is a sequence control 3d, high voltage power supply 32, directional gyro 34, depth control 36, and an electronic ampler 4t). Within the afterbody 13 is an electric drive motor 46, and depth and course control solenoids 4S.

In FIG. 2 the target is shown installed in a submarine torpedo tube 52 for launching. A clamp 54 secures the target to a roller 58 in the bottom of the tube. To launch the target the torpedo tube is irst flooded. The sea water activates battery 24 which generates 24 volts.

As is shown in FIG. 3, power is supplied immediately to the rotor 94 of the gyroscope 34 and to the heater of the thermal time-delay switch 70. This switch holds its contacts '72 open for approximately 60 seconds to prevent other units of the target from operating until the gyro rotor 94 reaches its operating speed so that the target will have directional stability when released. After switch '70 closes its contacts 72, the target is ready to be released from the torpedo tube.

The release cable 64 in FIG. 2 is wound onto reel 60 and thereby drawn through a packing in the breech door 62 of the torpedo tube. This action draws pin 56 to release the target from clamp 54, and also draws pin 66 to close a release switch 45 which is shown in FIGS. l and 3.

In FIG. 3, contacts 72 of delay switch '70, and release switch 45 apply 24 volts from the battery to the coil of relay 74. Relay '74 closes, locks in, and applies 24 volts to the heater of a second time delay switch 76, to the heaters of the amplier 4d, to the depth control 36, to the uncaging solenoid 99 of the gyro 34, to the course control relays 88 and 9d, and to the drive motor 46. The drive motor 46 starts and turns the propeller 50 so that the target swims out of the torpedo tube and proceeds at a speed of approximately four knots. It is the purpose of the second time delay 76 to provide an interval between the releasing of the target and generation of simulated noises, during which the target may move far enough away from the launching submarine so that reflections from the submarine will be too weak to sustain oscillation of the echo repeater. The mercury switches 84 and 85 of the depth control 36 are operated by water pressure in a bellows 96, which operates against a spring 98 which regulates the movement of an arm 95 that supports the mercury switches. The graduated dial 44 provides a means oi regulating the force of said spring against the arm 95 for setting the depth at which the target will operate. The mercury switches S4 and 86 are so adjusted that they energize one or the other of elevator solenoids 78 whenever arm 95 is 1 or more from a horizontal position. Thus the mercury switches, by controlling the solenoids 78, will tend to regulate the angle of climb or dive of the target so as to hold the arm 95 in a level position. Should the target be launched from, or otherwise attain a depth that is not the same as the setting of the adjustment dial 44, the water pressure dierence in the bellows 96 will move the arm d5 so that it lies at an angle above or below the axis of the hull. Thereupon the mercury switches 84 and Sd so control the solenoids 78 as to maintain arm 95 in a level position and thereby put the target into a climb or dive.

When the voltage is applied to the uncaging solenoid 99 it sets in operation the directional stabilizing equipment. This releases the gyros gimbals from the caging mechanisrn to allow the gyro to run free. The uncaging mechanism is connected to a course setting dial 42 that pre-sets the position in which the gyro will operate. A brush 91 is fastened to the outer gimbal and wipes a contacto; ring 93. When the target is oit the set course one segment of the contactor ring 93 is in contact with the brush 91, and power is supplied to the proper rudder solenoid S0 through relay 88 or 9d to bring the target on course. By means of the dial 42 the course of the beacon is adjustable up to left or right of the heading of the target when released.

The second time delay switch '76 closes approximately 55 seconds after the target is released, and thereby closes relay 92 which connects +24'volts to the high voltage power supply 32 which supplies -l-B power to the echo repeater amplifier 40. Relay 92 also supplies power to the noise simulator rnotor 26which will be described presently. This action thus puts the target into full operation.

A pressure operated safety switch 38 is provided in the negative power lead that energizes relay 92. This switch opens when the target goes below a depth of 125 feet, and since relay 92 connects power to the noise simulator motor 26 and echo repeater high voitage power supply 32, these units can be silenced in an emergency, if the target becomes caught on the submarine after launching, by diving to a depth in excess of 125 feet.

The simulator section 11 (FIG. l) consists of an electric drive motor 26 and a gear train 28 that generate a gear whine and a propeller cavitation noise that simulate the underwater sounds of a submerged submarine. In FIG. 4 the motor 26 of the simulator unit drives the gear 100 at 1200 revolutions per minute (rpm.) to generate a gear whine having a fundamental frequency of 300 cycles per second. Every fourth tooth of the gear 100 is .010 inch higher than the other teeth. Thus during each revolution of the gear fifteen high teeth are caused to strike against two rollers 108 that are located diametrically on either side of the gear. These rollers 108 are mounted in hinged supports 110 that transmit vibrations from the rollers to striking pads 1112, that are adjusted to rest against the simulator case 106 so as to transmit the vibrations to the sea water. A similar roller 114, and striking pad 11e, are employed to generate a propeller cavitation noise of 120 beats per minute. The roller being actuated by an eccentric gear 104 that rotates 120 per minute. The gear 104 is .010 inch off center and in operation only the high side of the gear strikes the roller 114 to generate the simulated propeller cavitation noise. FIG. 4 is diagrammatic in that it does not show the gears in the compact assembly that is actually used.

Although here illustrated by a specific embodiment, the present invention should be limited only in accordance with the claims.

We claim:

1. In a self-propelled underwater decoy, an elongated hull having propulsion means, depth control for said hull comprising a hinged horizontal fin attached to the stern of said hull and actuated by a pressure-responsive device, directional control for said hull comprising a hinged vertical n attached to the stern of said hull and actuated by a gyroscope, a receiving transducer, an amplier and a transmitting transducer carried by said hull to repeat sounds received by said receiving transducer, motor means driving a gear train positioned within the hull, and means bearing on the periphery of at least one of the gears in said gear train and mechanically connected to said hull so that said hull is vibrated by rotation of said gear train and transmits sound waves of a predetermined frequency to the surrounding water.

2. In a self-propelled underwater decoy having an elongated closed casing, propelling means for said casing, motor means driving a disc having a serrated periphery thereon, and means connected to a portion of said casing and bearing on said periphery of said disc so that rotation of said disc vibrates said casing at a frequency determined by the peripheral speed of said disc and thereby causes said decoy to transmit to the surrounding water sounds similar to those normally produced by a submerged submarine.

3. In an underwater self-propelled decoy having an elongated casing, propelling means for said casing, motor means driving a series of intermeshed gear Wheels each revolving at a diiferent speed, first mechanical means connected to said casing and bearing on one of said gear wheels to vibrate said casing at one frequency, and second mechanical means connected to said casing and bearing on a different one of said gear wheels so as to vibrate the hull at a different frequency, said combined vibrations being designed to simulate the noise of a submerged submarine.

4. In an underwater self-propelled decoy having an elongated casing, a longitudinal section of said casing being composed of thin elastic material, propelling means for said casing, motor means driving a disc having a serrated periphery with periodic serrations projecting to a larger radius than the remainder of said serrations, and mechanical means secured to said longitudinal section and bearing on said periodic serrations so that said longitudinal casing is vibrated at a periodic rate by rotation of said disc.

5. A self-propelled underwater decoy adapted to be launched from a submerged vessel, comprising an elongated hull, means for propelling the hull at a predetermined speed, means responsive to the pressure of the surrounding water for maintaining the hull at a predetermined depth, means including a gyroscope for maintaining the hull on a predetermined course with respect to the submerged vessel, echo producing apparatus including a receiving transducer, an amplifier and a transmitting transducer carried by the hull for repeating each compressional wave impinging on the receiving transducer a predetermined period of time after the compressional wave is received by said receiving transducer, means for generating a gear-whine within the hull having a predetermined fundamental frequency, eans for periodically vibrating a portion of the hull so that it produces compressional waves in the sea water having a frequency designed to simulate compressional waves normally produced by submerged vessels, a second means for vibrating the hull at a frequency different from that produced by said first hull vibrating means so as to produce compressional waves in the sea water similar to those resulting from normal propeller cavitation of submerged vessels, means energizable by the surrounding sea water for generating power to drive the propelling means, the gyroscope, the echo producing apparatus and the hull vibrating apparatus, and means for delaying the application of power to the echo apparatus and the hull vibrating apparatus for a predetermined period of time after the hull is propelled from the submerged vessel.

References Cited in the tile of this patent UNITED STATES PATENTS 613,809 Tesla Nov. 8, 1898 1,427,560 Sperry Aug. 29, 1922 1,610,779 Hewett Dec. 14, 1926 2,397,107 Hammond Mar. 26, 1946 2,397,844 Dewhurst Apr. 2, 1946 2,406,111 Sheteld Aug. 20, 1946 2,409,632 King Oct. 22, 1946

Claims

2. IN A SELF-PROPELLED UNDERWATER DECOY HAVING AN ELONGATED CLOSED CASING, PROPELLING MEANS FOR SAID CASING, MOTOR MEANS DRIVING A DISC HAVING A SERRATED PERIPHERY THEREON, AND MEANS CONNECTED TO A PORTION OF SAID CASING AND BEARING ON SAID PERIPHERY OF SAID DISC SO THAT ROTATION OF SAID DISC VIBRATES SAID CASING AT A FREQUENCY DETERMINED BY THE PERIPHERAL SPEED OF SAID DISC AND THEREBY CAUSES SAID DECOY TO TRANSMIT TO THE SURROUNDING WATER SOUNDS