US2404266A - Mine detection device - Google Patents

Description

Jufiy 1, 1946- M. H. LbUGI-LNAN E MINE DETECTION DEVICE 1 Filed June 18, 1943 2 Shets-Sheet 1 t 2/ 113F320 2a 11 f 23 ATTOHVE'Y.

July 16, 194-.

M. H. LOUGHNANE MINE DETECTION DEVICE Filed June 18, 1943 2 She e cs-Sheet 2 ISTRIEUTIJR M A A I'EIEI Patented July 16, 1946 Michael Henry Loughnane, Little Falls, N. J.

Application June 18, 1943, Serial No. 491,338

4 Claims.

This invention relates to improvements in mine detection devices and specifically it relates to a system employing a plurality of propelled and controlled torpedo-like detection vessels operated in front of the ship to be protected and an electrical detection circuit comprised in the control cables of said detection vessels whereby approaching mines are automatically indicated on the ship to be protected.

The protection of ships against mines is a problem which is of great importance and which has puzzled naval designers for many years. Various forms of protection has been devised such as blisters and nets, etc., but most of these devices were extremely cumbersome and were not effective when the ship was under speed. My present invention solves this problem in a new and unique manner without any cumbersome armor or other hindrances to the operation of the ship at full speed. By means of adetection apparatus comprising a plurality of torpedoshaped feelers which are electrically driven from the mother vessel, and which may be controlled from same and operated far in advance of same, I am able to detect and automatically indicate the position of mines in time to either reverse the engines and stop the ship or to change the course and get out of the way. This device may also be operated as an advance feeler by submarines or mine sweepers seeking a channel through enemy mine fields. It is believed that this device will be of great value on the protection of both naval and merchant shipping.

An important object of this invention is to provide a simple and easily operated detection device which will give automatic indication when a vessel is approaching a mine.

Another object of this invention is to provide a detection system for mines which may be operated suificiently far ahead of a moving vessel to either reverse the engines and stop same or to change the course and get out of the way.

Still another object of my invention is to provide an automatic, electrically operated detection system which will indicate when a vessel is approaching a mine as well as the approximate direction and location of the mine.

A further object of this invention is to provide a mine detection system which permits operation and automatic indication while the vessel is under full speed.

Other objects and advantages of my invention will be apparent during the course of the following description.

In the accompanying drawings forming a part sulator I4, see Fig. l. I

are connected through insulated leads carried 2 of this specification, and in which like numerals are employed to designate like parts throughout same,

Figure l is a plan view showing a schematic arrangement of a detection device embodying my invention,

Figure 2* is a sectional elevation of one of the torpedo-shaped feelers, and,

Figure 3 is aschematic diagram of the detection and indicating circuit.

In the drawings, wherein for the purpose of illustration is shown a simplified and preferred arrangement of my invention, the numeral 5 designates the ship to be protected. On the forward part of the ship 5 are placed reels 6 and I from which cables 8 and 9 extend forward to the torpedo-shaped detectors or feelers I0 and I I. A cable I2 is connected withone end through the insulated lead-in I3 to the feeler Ill and with the other end to insulator I4. Another cable I5 is connected through the insulated lead-in I6 to the port feeler II and with its other end to insulator I4. A mine field comprising mines I'I, I8, I9, 20 and 2| is indicated in dotted. lines, see Fig. 1.

The torpedo-shaped feelers I0 and II are constructed as indicated in the sectional elevation. shown in.Fig. 2. The torpedo-shaped body I0 has a propeller 22 at its forward end. A protective frame 23 prevents damage to the propeller from driftwood or other objects. The propeller 22 is driven by the electric motor 24 through the gear reduction 25. At its rear end the torpedoshaped body I0 carries horizontal and vertical rudders 26 and 21 which are operable by means of the electricmotors 28 and 29, respectively, through the gear reductions 3B and 3i. The tow cable 8 carries several insulated'conductors which provide power and control to the various motors as well as carry thedetection current. "The cable "8'is preferably brought to a distribution box 32 from which separate connections are brought to the motors and to the insulated leadins I3 and I6.

-The'detection circuit as illustrated in Fig. 3 consists of the two bare cables I2 and I5 which are insulated from one another by means of in- These cables I2 and I5 in the two tow cables 8 and 9 to the variable resistor 33 from which leads 34 and 35 connectto transformer 36 which again feeds into the twogrids of tube 31. The sliding member. of the variable resistor 33 is connected through lead 38 f to one terminal of coil 39 0f the power transformer 40 while the other terminal of coil 39 is connected to ground through lead 4!. The center tap of transformer 36 is connected to the slider of a variable resistor 42 by means of lead 43. The remainder of the circuit consists mainly of the amplifying tube 44 which has two plates and two grids and which is connected so as to amplify the impulses coming from tube 31, and the two relays 45 and 55. Through leads 4?, 48 and 49 the'relays 45 and 46 may be used to control automatic signalling means such as visible indicators or even to control rudder or engine room signals. The lead 41 is common while 48 indicates port and 49 starboard. The power transformer 40 furnishes the necessary operating voltages and is connected to a suitable source at terminals 50 and 5|. The tube 44 is preferably of a type known to the art by the trade-name Thyratron. It is to be noted, however, that other tubes and other circuits may be used to obtain the same result without departing from the object and nature of my invention.

The operation of my invention is as follows: As mentioned supra the motor-driven, torpedoshaped feelers are powered by electric motors and controlled from the ship to be protected. These feelers I and I! are sent out ahead of the ship and operated at a suitable distance away from same. The electric motors 24 furnish an excess of power thus giving the feelers a greater speed than the ship 5. In this manner the tow lines 8 and 9 will be held taut as will the cables I 2 and [5 due to the fact that the rudders 26 are set so as to give the feelers I0 and I I a slight angle outward from the ship 5. Due to the fact that feelers l0 and ll have a higher speed than the ship 5 it is also possible to make turns at full speed by properly controlling said feelers and by pulling in on one or the other of the cables 8 and 9 if necessary. The feelers are designed to have sufficient buoyancy to float and to carry the cables 8, 9, I2 and I5 and their elevation may furthermore be controlled by means of rudders 21. The electric motors 24, 28 and 29 are preferably arranged so as to minmize any gyroscopic action.

The bare cables 12 and form one half of a Wheatstone bridge, as shown in Fig. 3, with the variable resistor 33 forming the other half. A voltage is applied to this bridge circuit from coil 39 through leads 38 and 4|, the current traveling through the salt water and through the body of the feelers l0 and H. Normal zeroindication is set by adjusting the variable resistor 33. The cables l2 and 15 are bare and in contact with the salt water, but are insulated from the bodies of feelerslil and I l by means of the lead-ins l3 and 16. Being of equal length the resistance of cables l2 and [5 to ground will also be equal. It is therefore only necessary to adjust resistor 33 to obtain perfect balance in the bridge circuit. 'Ihis'balance is furthermore adjusted to match tube 3'! by means of resistor 42. With the bridge on balance no voltage will flow in the secondary of transformer 36. Any small change in the contact areas of the cables l2 and [5, however, will, immediately result in the upsetting of this balance and a voltage will be induced in transformer 35. If, therefore, a mine or any other metallic object comes into the vicinity of one of the cables l2 or I?) the balance will be upset and being polarized the induced voltage in transformer 36 will act on either one or the other of the grids of tube 37 and accordingly operate either one or the other of the plates of the Thyratron 44, thereby operating either one of the relays 45 or 46. It is thus not necessary for the mine to touch the cables l2 or 15 and it is obvious that the indication given will be proportional in strength to the distance between the mine and the cable. Thus it is also possible to obtain an indication of the distance away from the mine as well as whether it is approaching th starboard or the port cable. In this manner a quick and reliable indication is obtained and it is possible to either stear away or to reverse the engines and stop the ship in time before hittin the mine. It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example only, and that various changes? in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A mine detection device for ships comprising a plurality of feelers, said feelers being electrically driven and controlled and operated ahead of the ship to b protected; electrically operated rudder means controlling said feelers; insulated,.multiconductor cables connecting said feelers to said ship; a pair of bare cables, mechanically connected together but insulated from each other 'at their connected ends as well as from the body of said feelers, said bare cablestying said feelers together mechanically, and automatic detection means comprising a balanced bridge circuit, of

which said bare cables form one half, whereby-the proximity of mines or other metallic objects may be indicated.

2. A mine detection device for ships, comprising a plurality of electrically driven, torpedoshaped feelers operated at a considerable distance ahead of the ship to be protected; electrically operated rudder means whereby said feelers may be controlled from the ship; insulated, multiconductor cables connecting said feelers to said ship; a pair of bare cables forming a tie between said feelers, said bare cables being insulated from one another as Well as from the bodies of .said feelers; a Wheatstone bridge circuit including said bare cables and said insulated cables} avariable resistor forming two legs of said bridge. circuit; a polarized amplifying circuit connected to said bridge circuit, and indicating means operated by said amplifying circuit whereby the proximity of a mine may be indicated...

3. A mine detection devicefor ships comprising a plurality of feelers, said feelers .being electrically driven and controlled andoperated ahead of the ship to be protected; electrically operated rudder means whereby said feelers may be'controlled from the ship; insulated multi-conductor cables connecting said feelers to said ship; alpair of .bare cables forming'a tie'between 'said feelers, said bare cables being insulated from one another at their common ends as well as fromthe bodies of said feelers, said barecabl'es' being connected through insulated lead-ins to said insulated multiconductor cables; a potentiometer connected, across said insulated cables, said bare cables, insulated cables and potentiometers forming a bridge circuit; a sensitive detection circ'iiito'nnected across said potentiometer, and remote control means operated by said sensitive detection circuit whereby the proximity of amine maybe detected.

4. A detector device comprising a plurality of. electrically driven torpedo shaped feelers operated at a considerable distance ahead of the ship to be protected; electrically operated rudder means whereby said feelers may be controlled from the ship; and insulated multi-conductor cable connecting each of said feelers to said ship; a pair of bare cables forming a tie between said feelers; said bare cables being tied together through an insulator at their common end and connected to a separate lead in said insulated cables through an insulated lead-in in said feelers; a potentiometer connected across said leads of said insulated cables, said potentiometer forming the two arms of a bridge circuit, while the two other arms are being formed by said bare cables; a sensitive detection circuit connected across said potentiometer and comprising an input transformer connected into a dual detector and am- 15 MICHAEL HENRY LQUGI-INANE.

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