US2400549A

US2400549A - Mine firing device and control means therefor

Info

Publication number: US2400549A
Application number: US429404A
Authority: US
Inventors: James B Glennon; Robert H Park
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-02-03
Filing date: 1942-02-03
Publication date: 1946-05-21
Anticipated expiration: 1963-05-21

Description

May 21, 1946. J. B. GLENNON ET AL MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Fil ed Feb. 3, 1942 6 Sheets-Sheet l INVENTORS JAMES B. GLENNON ROBER H. PARK MayZl, 1946. J. B. GLENNON ETAL 2,400,549

MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Filed Feb. 5, 1942 e Sheets-Sheet 2 I I" I Q INVENTORS JAMES B. GLENNON R BERT H. PARK ATTORNEY y 1, 1946. E J. B. GLENNON ETAL 2,400,549;

MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Filed Feb. 3, 1942' 6 Sheets-Sheet 3 INVENTORS JAMES B. GLENNON y 1946- J. B. GLENNON ETAL 2,400,549

MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Filed Feb. 5, 1942 6 Shees-Sheet 4 INVENTORS JAMES, B, GLENNQN' ROBERT H. PARK A ORNEY y 1946- J. B. GLENNON ET AL 2,400,549

MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Fil ed Feb. 3, 1942 6 Sheets-Sheet 5 INVENTQRS JA ES B. GLENNON ROERT H. PARK y 1, 1946. J. B. GLENNON ETAL 7 2,400,549

MINE FIRING DEVICE AND CONTROL MEANS THEREFOR Filed Feb. 3, 1942 e Sheets-Sheet e INVENTORS 1 JAMES B. GLENNON ROBERT H. PARK Patented MayZl, i946 FIRING DEVICE AND CONTROL MEANS THEREFOR James B. Glennon, Washington, D. 0.. and

Robert H. Park, Pluekemin, N. J.

Application February 3, 1942, Serial No 429,404

11 Claims. (Cl. 102-48) (Granted under the act or March 3, 1883, as amended April 30, 1920; 370 0. G. 757) v This invention relates to firing devices for a submarine mine and control means therefor in which the mine is prevented from detonation as the result of a shock or pressure impulse received from a countermining operation or the mine is otherwise disturbed. More specifically the invention provides a system i or firing a submarine mine in response to a change in the magnetic field adjacent thereto caused by the approach of a steel vessel or other ponderous mass of magnetic material moving within the vicinity of the mine in which the mine is armed within a predetermined period of time after the mine has been launched within a, body of water and in which a pendulum device is employed to control the operation of a slow acting relay to interrupt the firing circuit and prevent the premature detonation of the mine as tacts adjacent thereto and the operation of a slow acting time delay device having a pair of firing contacts thereon adapted to operate a detonating device is thus prevented.

The system .of the present invention comprises,

means for detectinga change in the magnetic field adjacent the mine such, for example, as an induction pick-up coil operatively connected to the winding of a, sensitive relay whereby the relay is caused to close a pair of electrical contacts in response to a change in the earth's magnetic field produced by an approaching steel vessel orother ponderous mass of magnetic material movpendulum contacts as the pendulum operates.

Such arrangements have not proven altogether satisfactory in service for the reason that the circuits above referred to are closed by the pendulum as the pendulum returns to a normal unoperated position or passes through the normal position during each swing or oscillation thereof while the mine is in a disturbed state as the result of the vibrations or pressure impulses received through the surrounding water and, for this reason, there is a possibility of the mine being prematurely fired as the result of a countermining operation or other disturbance of the mine.

In the system of the presentinvention a pendulum assumes a vertical position by reason of the provision of gimbals upon which the pendulum is mounted such that the pendulum contacts are normally disengaged from each other. When the mine is disturbed the pendulum contacts are closed thereby causing a slow-to-release relay to be operated and interrupt the firing circuit continuously during the time the pendulum is oscillating or vibrating through an angle sufiicient to close the contacts thereof. The slow-torelease relay also causes the'armature of a sensitive detecting relay to be maintained in a predetermined position such that the armature contacts thereof are disengaged from a'pair of control coning within the vicinity of the mine. The sensitive relay is provided preferably with a resetting mechanism comprising a reset or a restoration magnet adapted to reset the relay to a neutral or null position as the reset magnet is energized. There is also provided a time delay device controlled by the sensitive relay adapted to close a firing circuit after a predetermined period-of time has elapsed immediately following the operation of the sensitive relay.

A detonator is inserted within an explosive booster charge by the pressure of the water on a flexible diaphragm having one side thereof in communication with the 'water after a soluble washer connected thereto has dissolved or softened sufiiciently to permit inward movement of the diaphragm. The movement of the diaphragm inwardly causes a pair of electrical contacts to be closed thereby operatively connecting the sys-' tem with a sourceof'electrical power and causing the restoration magnet to operate over a circuit including a slow acting'fuse, the fuse being sufiiciently slow in' operation to insure the resetting of the sensitive relay to the null position before the fuse blows and the circuit to the reset magnet is interrupted thereby.

One of the objects of the present invention is the provision of new and improved means for pre venting the premature detonation of a mine in response to a, counterminingoperation.

Another of the objects is the provision oi new and improved means for arming a submarine mine within a predetermined period of time after the mine has been launched within a body of water.

Another object is the provision of a mine firing control system which will be economical to manufacture, reliable in operation and which possesses all Of the qualities of ruggedness and dependability in service.

Still other objects, advantages and improve- 2 I ments will be apparent from the following description taken in connection with the accompanying drawings of which:

Fig. 1 is a view in section partly broken away of a submarine mine according to a preferred form of the invention;

Fig. 2 is a plan view of the firing control device of Fig. 1 with the upper cover thereof removed;

Fig. 3 is a view of the device taken substantally along the line 3-3 of Fig. 2;

Fig. 4 is aview partly broken away taken along the line 4-4 of Fig. 2;

Fig. 5 is a fragmentatry view taken along line 5-5 of Fig. 2;

Fig. 6 is a view considerably enlarged taken along the line 5-6. of Fig. 5;

the

Fig. 7 is a view partly broken away taken along I the line I-I of Fig. 2;

Fig. 8 is a fragmentary view considerably enlarged taken along the line 8-8 of Fig. 7, and;

. Fig. 9 illustrates in diagrammatic form the electrical circuit arrangement of the entire system.

Referring now to the drawings and more particularly to Fig. 1 thereof there is shown thereon a submarine mine indicated generally by the numeral II comprising a casing I2 preferably rounded at one end thereof and provided with a. cap l3 secured thereto as by the bolts I4, a suitable gasket I5 being provided between the casing and the cap to prevent the seepage or leakage of water therebetween. The mine is also provided with a recessed portion I8 having a shoulder II adapted to engage a soluble washer I8 of any material suitable for the purpose such, for example, as a composition of salt, glue, glycerin and the like. Secured to the recessed portion I6 as by the bolts I9 is an insert or bearing support 2| adapted slideably to support a hydrostat device comprising a shaft or plunger 22 having a flexible diaphragm 23 secured thereto in any suitable manner as by the nut 24, the outer edge of the diaphragm being clamped-to a shoulder 25 within the recessed portion I5 as by the bolts 26 and clamping ring 21. A spring 28 disposed about the shaft 22 normally urges the diaphragm outwardly.

The soluble washer I8 is secured to the outer end of the shaft 22 in any suitable manner as by the nut 29, suitable washers being arranged preferably between the nuts 24 and 29 and the soluble washer. Secured to the shaft 22 in any suitable manner at the innermost end thereof is a detonator 3I adapted to be inserted within a booster charge 32 as the hydrostat operates. The re.- cessed portion I6 is preferably braced at the lower end thereof to the casing I2 of the mine as by the member 33 extending therebetween. There is also secured to the shaft 22 a collar 34 adapted to cause a flexible contact sprin 35 to be moved into electrical engagement with the insulated contact spring 35 as the hydrostat operates. The contact spring 35 is in electrical contact with the 'mine casing I2 as by riveting or clamping the parts together whereby the insulated spring 36 is grounded to the casing of the mine as the contact spring 35 engages the contact spring 36 in response to the operation of the hydrostat.

The casing is also provided preferably with an aperture 31 whereby'an explosive mixture 38 such as TNT or the like is introduced within the mine casing, the aperture being sealed by a plate or cover 39 secured thereto as bythe bolts 4|, a gasket 42 being provided to insure a hermetically sealed joint therebetween.

There is also provided within the mine casing 44 to prevent injury to the battery or the parts adjacent thereto during the handling. transportation and planting of the mine.

There is also provided a, well 46 secured in any desired manner to the recessed portion 44 having a pad or cushion 41 therein adapted to receive and support one end of aninduction coil 48, the other end of the induction coil being supported by a similar pad or cushion 49 disposed within the well 5| secured to an inner end of the casing I2. The coil 48 consists preferably of a lar e number of turns of fine wire arranged about an iron core or a core composed of a material known in the art as Permalloy having a composition of substantially 87 /2 percent iron and 12% percent nickel thereby to increase the electromotive force generated by the coil in response to a predetermined change in the magnetic field adjacent thereto.

Disposed between the well 43 and the cap I3 is a resilient pad or cushion 52 of material suitable for the purpose such, for example, as sponge-rubber adapted to receive and support a mine firing and control mechanism indicated generally by the numeral 53 having a screw terminal 54 thereon adapted to establish an electrical connection between the mine firing control mechanism and an electric conductor 55,' the other end of the conductor 55 being connected to the casing of the mine as by the screw or bolt 55. The battery EA is connected at one terminal thereof to the mine firing control mechanism 53 by one'of the conductors within the electrical cable 51 extending therebetween, the other pole of the battery being connected to the casing of the mine by the screw 56. A tube or cable duct 58 extends between the partition or wall 43 into the recessed portion I6 of the mine casing whereby an external electrical connection between the mine firing control device 53 and the detonator 3I may be established by way of the electrical conductors arranged-within the tube and insulated. therefrom; The tube is provided with a branch 59 extending therefrom within which are disposed a pair of electrical conductors extending to the induction coil 48.

On Figs. 2 to 8 are shown several views of a mine firing control mechanism suitable for use with the present invention, the mechanism comprising, among other elements, a mounting ring 8|. Afflxed to the mounting ring in any suitable manner as by the bolts 52 and nuts 63 are the detachable upper and lower covers 54 and respectively, a pair of

gaskets

66 and 61 being provided preferably between the upper and lower covers respectively and the ring BI additionally to protect the mine firing control mechanism from exposure to the effects of water which might seep into the mine as the result of damage or injury to the casing thereof.

The mounting ring 5| is provided with a pair of bosses or bearing supports 88 and 69 diametrically arranged in respect thereto, each of the bosses having an insert or sleeve III and II respectively arranged therein. The sleeve III is provided with a bolt or contact rod I2 insulated therefrom as by the insulating sleeve 13 and washer 14 held securely in clamped position by the nuts II and I8 threaded on the bolt I2. The sleeve III also supports a ball bearing 11 in registeredengagement with a gimbal ring I8 whereby the gimbal ring is adapted to be rotated about the axis of the sleeve vided in which the frame 10. Secured to the gimbal ring as by the screws 19 is a contact spring 8I adapted to engage a contact 82 on the end of the rod 12 whereby an electrical connection is established between the

conductors

88 and 84 connected to the contact spring 8| and the rod 12 respectively. The contact spring 8| is insulated from the gimbal ring as by the bushing 85 composed of suitable insulating material such, for example, as Bakelite, hard rubber or the like.

In-a similar manner the sleeve II within the bearing support 89 supports a contact rod 81 arranged within an insulating sleeve 88. and provided preferably with a nut 89 for establishing.

a circuit with an electrical conductor 9|. Disposed about the sleeve 88 is a conducting sleeve 92 to which is secured the conductor 93 as by the nuts 94, the sleeve 92 being electrically insulated from the sleeve 86 by the insulating sleeve 85. The ball bearing 96 is mounted upon the sleeve 1i and in registered engagement with the gimbal ring 18 whereby the gimbal ring is adapted to rotate freely about the sleeve 1 I 'The stud 81 is provided with a rounded or pointed end 91 adapted to engage a contact spring 98 continuously and thereby maintain a continuous electrical circuit between the conductors 9! and 99 affixed to the rod 81 and contact spring 98 respectively. The sleeve 92 is provided with a cylindrical portion at one end, thereof in continuous engagement with the contact spring IOI having a conductor I02 secured thereto thereby providing an arrangement in which a continuous electrical circuit is established between the conductors 93 and I02. The contact springs 99 and I02 are clamped to the gimbal ring 18 as by the screws I03 and nuts I04 and suitably insulated therefrom as by the insulating bushing I05.

There is also provided two supports or bosses I06 and I01 whereby the mounting frame I08 is rotatably supported by the ball bearings I09 and II I. The frame I08 comprises two plates H2 and H3 secured to the end members H4 and I I as by the bolts IIB. An arrangement is thus pro- I08 is rotatably mounted on gimbals within the supporting ring 6|, the frame being maintained in a predetermined upright position by reason of a suitable counterweight I I1 secured thereto as by the bolts II8.

The end plate H4 is provided with a centrally arranged aperture adapted to receive an insulated sleeve I I9 within which is' arranged a metallic sleeve or bushing I2I of material suitable for the.

purpose such, for example, as brass or phosphorbronze. Within the sleeve I2I is disposed a rod I22 electrically insulated therefrom as by the insulating sleeve I23. The sleeve I2I is adapted to be engaged by the contact spring I24 whereby an electrical connection is continuously maintained between the conductor 99 and the conductor I25 secured to the sleeve I2I as by the nuts I25. The rod I22 is provided preferably with a rounded or pointed end adapted to engage the contact spring I21 and thereby maintain a continuous electrical connection between the conductor I02 and the conductor I28 secured to the rod I22 as by the nut I29 and washer I 3I. The contact springs I24 and I21 are clamped to the gimbal ring 18 as by the screws I32 and nuts I33, a bushing I34 of material suitable for the purpose such, for example as hard rubber, Bakelite or'the like being provided to insulate the contact springs I28 and I21 from the gimbal ring and from each other. There is also provided a disk or plate I35 secured to the gimbal ring 18 as by the screws I 38 thereby securely maintaining the bearing I09 in fixed relation-with respect to the gimbal ring 18,

the plate I35 having an aperture therein within v the screws I39 is a contact spring I adapted to engage one end of the contact stud I31 and maintain a continuous electrical connection between the conductor 83 aflixed to the contact spring I4I and the conductor I42 secured to the contact stud I31 as by the nuts I43. In a similar manner the bearing II I is secured to the gimbal ring 18 by the plate I44 and screws I45. Secured to the plate I I3 in any suitable manner by the screws I46 is a sensitive relay I41, hereinafter referred to as relay A having the operating winding thereof connected to the induction pick-up coil and adapted to be operated by the current received from the induction coil in response to a change in the magnetic field adjacent thereto, the relay comprising, among other elements, a pair of conductors I48 whereby the external circuit to the reset magnet of the relay A is established.

There is also provided a fuse I49 hereinafter referred to as F supported preferably by the fuse clips I5I secured to the" plate H3 and suitably insulated therefrom, the fuse being in electrical circuit with the reset magnet of relay A and adapted to cause the reset magnet to operate after the mine has been launched within a body of water and thereafter interrupt the circuit to the reset magnet as the fuse operates. a A pendulum device I52, hereinafter referred to as P, is secured to the plate II3 as by the supports I53 and I54 in the manner illustrated, the supports I53 and I54 being provided preferably with clamping screws I55 and I56 respectively whereby movement of the pendulum device I52 with respect to the frame I08 is prevented. The pendulumdevice may be of any type suitable for the purpose such, for example, as the pendulum disclosed in the copending patent application of James B. Glennon and Chester M. Van Atta, Serial No. 395,230, filed May 26, 1941, for improvements in Firing mechanism for a submarine mine, the pendulum including a pair of normally disengaged electrical contacts adapted to close a circuit between the terminals I56 and I51 thereof whenever the pendulum device is disturbed as the result of a vibration or pressure impulse received through the surrounding water such, for example, as may be caused by a' countermining operation.

There is also providedan electro-responsive time delay device or relay I58, hereinafter referred to as B, having a pair of normally open contacts adapted to be moved to closed position after a predetermined period of time has elapsed immediately following the energization of the operate winding thereof. The relay may be of any well known type of construction in which a time delay mechanism comprising a dash pot, gear train and escapement' mechanism or the like may be employed to delay the closing of the relay contacts for a predeterminedperiod of time.

Secured to the plate II2 as by the screws I59 and supporting member I60 is a slow acting-relay I6I, hereinafter referred to as C, having a pair of normally closed contacts adapted to'be 4 I disengaged as the relayv operates and 'a pair of normally open contacts adapted to be moved into engagement with each other as the relay operengaged during the oscillation or-vibrat-ion of ates, the relay being provided preferably with a I copper Slug I62 disposed about the core of the the contacts thereof. I v

The operation of the system will now be described. Let it be assumed, by way of example, that the mine has been planted within a body of water for a period of time suiiicient to cause the soluble washer I8 to dissolve orv become sufllciently soft to allow the hydrostat to be operated by the pressure of the water against the flexible diaphragm. 23 thereof. When this occurs contact spring 35 is moved into engage ment with contact spring 36 thereby applying ground to conductor I63, Fig. 9, the circuit continuing by way of the reset magnet RS of relay A, conductor I64, fuse F, conductor I65, gimbal contacts G02, conductor I66, battery BA and thence to ground. The reset magnet RS of relay movement of the .pendulum sumciently to close A operates and causes the armature I61 thereof to be moved to a neutral or central position intermediate the contacts I68 and I69 of the relay. The fuse F, it will be recalled, is a slow acting fuse and for this reason the reset magnet RS is operated for a period of time sufficient to'reset the armature I61 to the null position intermediate the contacts I68 and I69 and disengaged therefrom before the fuse F operates. As the fuse operates the circuit to the reset magnet RS is interrupted and the armature I61 of relay A is released for movement in either direction from the reset position in accordance with the direction of flow of the current generated by the induction pickup coil 48 as the number of flux linkages thereof varies in response to a change in the magnetic field adjacent thereto. The mine is now in an armed condition.

Letit be assumed that a countermine operation occurs within the vicinity of the mine thereby sending a wave or'impulse of pressure through the water-of sufiicient intensity to cause the pendulum 1? to vibrate sufficiently to close the contacts thereof. When this occurs a circuit is closed from battery by way of conductor I66, I

gimbal contacts GC2, conductor I65, contacts of pendulum P, conductor I1I, winding of relay C, conductor I63,

contacts

36 and 35 of the hydrostat and thence to ground thereby causing relay C to operate and at the armature I12 thereof interrupt the circuit to the detonator 3I. The premature operation of the detonator during the time relay C is operated is thus prevented and the mine is in an unarmed condition until relay C releases. As armature I13 of relay 0 moves into engagement with the make contact thereof a circuit is 'closed from battery BA by Way of conductor I66, gimbal contacts G02, make contact and armature I13 of relay C, conductor I64, winding of reset magnet RS of relay A, conductor I63,

contacts

36 and 35 of thehydrostat and thence to ground thereby causing the reset magnet to operate and maintain the armature I61 of relay A in a position intermediate the contacts I68 and I69 of relay A and disengaged therefrom.

Relay C, it will be recalled, is a slow-to-release relay and for this reason does not release while the contacts of pendulum P are momentarily disthe pendulum. When the disturbance or pressure impulses received from the countermining operation have subsided sufficiently to cause the contacts of pendulum P-to'remain continuously disengaged, the .operate circuit to the winding of to signals received from the induction pick-up coil 43 as the magnetic field adjacent thereto is varied by the movement of a steel vessel or other Donderous mass .of magnetic material within the vicinity of the mine. C moves to its unoperated position a circuit is closed from the contacts of the time delay device B to the detonator 3I whereby the detonator is adapted to be operated as the contacts of the time delay device B are moved into engagement with each other. The mine is again in an armed condition.

Let it now be assumed that asteel vessel moves within the vicinity of the mine thereby causing a change in the terrestrial magnetic field adjacent the mine and an electromotive force within the induction pick-up coil 48 to be set up of sufficient magnitude to cause the relay A to operate, over the following circuit; ground at conductor I14, winding of induction pick-up coil 46, conductor I15,.gimbal contacts GCI, conductor I16, winding of the operate magnet of relay A, conductor I63,

contacts

36 and 35 of the hydrostat device from whence the circuit is continued to ground. As armature I61 of relay A moves into engagement with contact I68 or I69, as the case may be, battery is applied by way of conductor I66, gimbal contact G02, conductor I 65, armature I61 and make contact thereof, conductor I18, winding of the electromagnet of time delay relay B,'conductor I63,

contacts

36 and 35 of the hydrostat device and thence to ground thereby causing the electromagnet of the time delay clock B to be energized and move the armature I11 thereof away from the back stop I18. As armature I11 moves away from the back stop I18 9, gear train connected thereto is set in'motion to cause an escapement mechanism to operate and retard the movement of the armature I11 in response to the energization of the electromagnet thereof whereby the contacts I19 of the clock B are moved to closedposition when a predetermined interval of time has elapsed after the operate circuit to the electromagnet of the clock is closed. When the armature I11 has moved through an angular distance suflicient to cause the contacts I19 to be engaged, a firing circuit is closed from battery BA, conductor I66, gimbal contacts GCZ, conductor I65, timing clock contacts I19, conductor I8I,- armature I12 and break contact of relay C, conductor I81, gimbal contacts G03, conductor I83, detonator 3I, conductor I84,

contacts

36 and 35 of the hydrostat device and thence to ground thereby causing the detonator to operate and explode the mine.

Contacts I19 of relay B, it will be noted, are moved toclosed position in predetermined time delay relation with respect to the operation of relay A whereby the vessel is allowed to proceed As armature I12 of relay' on its course until it has attained a position substantially directly above the mine before the firing circuitis closed by the contacts I19 whereby the mine is caused to explode beneath a vulnerable portion of the vessel.

Armature Ill of the time delay relay device thereof is interrupted before the armature has moved through a distance suflicient to cause contacts I19 to be engaged as may occur, for example, as the result of the momentary movement of armature I61 of relay A into engagement of either of the contacts thereof as the result of a disturbance of the mine before armature I69 is forcibly moved to the neutra1 or null position contacts operatively connected to said slow releasing relay and adapted to cause said slowreleasing relay to operate as the pendulum device is moved from a position of rest, a. source of electrical power, detonatlng means operatively connected to the normally closed contacts of said slow releasing relay, and means controlled by the pressure of the water for causing said detonating mean to be operated by said source of electrical power as said normally open contacts of the time delay device are moved to closed position.

2. In a system of the character disclosed for controlling the firing of a submarine mine arby the operation of the restore magnet RS. The

retractile spring I85 is insufliciently strong to prevent movement of the armature I17 by the pull of the electromagnet of the time delay de vice as the electromagnet is energized.

Briefly stated in summa y, the present invention contemplates the provision of new and improved means for controlling the firing of a submarine mine by changes in the magnetic field adjacent thereto, in which the arming of the mine is delayed until a predetermined period of time has elapsed after the mine has been launched within a body of water, and in which the premature explosion of the mine as the result of a countermining operation is-prevented. Furthermore, the present invention provides a sysranged within a body of water, a firing circuit, means responsive to a predetermined change in the magnetic field adjacent the mine for closing said firing circuit, a pendulum device having a pair of normally open contact adapted to be closed as the mine is disturbed, and a slow releasing relay electrically connected to the contacts of said pendulum device and adapted to be operated thereby as the .pendulum device operates, said slow releasing relay having a pair of normally closed contacts adapted to be disengaged from each other and prevent the closure of said firing circuit while the slow releasing relay is operated a pair of normally open contacts adapted to be engaged with each other, and means controlled therebyto render said magnetic field tem in which the firing of the mine in response to a change in the magnetic field adjacent thereto as a steel vessel approaches within the vicinity of the mine, is delayed until the vessel has reached a position substantially directly above.

the mine whereby the maximum destructive effect of the mine is obtained.

responsive means inefifective to close the firing circuit while said slow releasing relay is operated.

3. In a system'of the character disclosed for controlling the firing of a submarine mine, -a source of electrical power, detonating means, a firing circuit adapted to establish a-nelectrical connection between said detonating'means and said source of power, said firing circuit including an electro-responsive device having means for closing said firing circuit in time delayed relation as the device operates, means including a sensitive relay controlled by a change in,the magnetic field adjacent the mine for causing said electro-responsive device to be set in operation,

' While the invention'has been described with reference to a certain preferred example thereof which gives satisfactory results, it will be understood by those skilled in the art to which the invention pertains, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it, is our intention, therefore, in the appended claims to cover all such changes and modifications.

The invention herein disclosed and claimed may be manufactured and used by or for the Government of the United States of America for govemthereon or therefor.

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

1. In a system of the character disclosed for controlling the firing of a submarine mine arranged 'within theterrestrial magnetic field on the bed of a body of water adjacent the path of travel of a vessel, means for detecting a change in said magnetic field, a sensitive relay electrically connected to said detecting means and adapted to be operated thereby, an electro-responsive time delay device controlled by said sensitive relay and having a pair of normally open contacts adapted to be closed as the time delay device operates, a slow releasing relay having a pair. of normally closed contacts in series circuit with-said normally open contacts of said time delay device, a pendulum device having a pair of normally open mental purposes without payment of any royalties a control circuit, a pendulum device having means for closing the control circuit as the mine is disturbed, and a slow. releasing relay connected to said control circuit and controlled by said pendulum device adapted to interrupt said firing circuit as the mine is disturbed.

4. In a system of the character disclosed for controlling the firing of a submarine mine disposed within a body of water adjacent the path of travel of a vessel, the combination of a firing circuit adapted to be closed in response to a change in one of the natural phenomena caused by 'the approach of a vessel within the vicinity of the mine, means for closing said firing circuit, a control circuit, a pendulum device having means for closing the control circuit as the pendulum device operates, a slow releasing relay electrically connected to said control circuit and adapted to be operated by said pendulum device,

a pair of normally closed contacts on saidslow releasing relay adapted to interrupt said firing circuit as the relay operates, a pair of normally open contacts on said slow releasing relay adapted to be closed, and means controlled thereby to render said firing circuit closing means inefi'ective to close the firing circuit as the relay operates.

5. In a system of the character disclosed for controlling the firing of a submarine mine arranged within a body of water adjacent the path of travel of a vessel, 'means for detecting a change in the terrestrial magnetic field adjacent the mine, a sensitive relay having a pair adapted to be brought into engagement selectively with said fixed contacts as a change in said magnetic field is detected by said detecting means, means including a reset magnet tor movfor establishing an electrical connection between said reset magnet'and the source of electrical power thereby to actuate the movable contact element oi! said sensitive relay to said predetermined open position, a slow acting fuse device adapted to disconnect said reset magnet from said source of power after the movable contact element has been actuated to said predetermined a time delay relay device electriopen position, cally connected to said sensitive relay and adapted to be operated thereby as said-fixed contacts are selectively engaged by said movable contact element in response to a change in the magnetic field detected by said detecting means, said time delay relay device having a pair of normally open contacts adapted to be engaged asthe timedelay relay device operates, a mine firing circuit adapted to be closed as the contacts of said time delay relay device are brought into engagement with each'other, a detonating device adapted to be operated as the mine firing circuit is closed, a

pendulum device having means for closing an I 2,400,049 of fixed contacts and a movable contact element I electrical control circuit as the pendulum device operates, and means including a slow operating relay electrically connected to said electrical control circuit and controlled by said pendulum device for interrupting said mine firing circuit when the time delay relay device is operated.

6. In a system for controlling a submarine mine, a source of electrical power, means controlled by the pressure of the water within which the mine is submerged for establishing an electrical connection to said source of electrical power, a sensitive relay having a movable element adapted to engage a pair of contacts selectively as the relay operates, means controlled by said pressure responsive means for setting said movable element in a predetermined position intermediate said pair of contacts and disconnected therefrom, means for releasing said setting means, means responsive to a change in the magnetic field adjacent the mine for causing said movable element to engage said pair of contacts selectively, an electroresponsive time delay mechanism operatively connected to said sensitive relay and adapted to be set in operation as one of said pair of contacts is engaged by saidmovable element, said time delay mechanism having a pair of normally open contacts adapted to be closed as the time delay mechanism operates, a detonating device in electrical connection with the normally open contacts of said time delay mechanism and adapted to be operated asthe contacts are closed, a slow releasing relay having a pair of normally closed contacts adapted to be disengaged and interrupt said electrical connection as the relay operates, and a pendulum device having means for closing an electrical circuit to said slow releasing relay as the mine is disturbed thereby to cause the slow releasing relay to be operated by said source of electrical power.

'7. In a system of the character disclosed for preventing the detonation of a submarine mine in response to a disturbance caused by a coun- 'termining operation, a source of electrical power,

a mine firing circuit connected to said source of electrical power, means responsive to the approach of a-vessel for closing said mine firing circultwhen the mine is undisturbed, a control circuit, a pendulum device having means for closing the control circuit from saidsource of power as an impulse of hydrostatic pressure sumcient to disturb the mine 'is received, a slow releasing relay adapted to be operated by said source of electrical power as the control circuit is closed, a pair of normally closed contacts on said slow releasing relay adapted to interrupt said firing circuit as the slow releasing relay operates in re- .sponse to the operation of said pendulum device,

a pair of normally open contacts on said slow releasing relay, and means controlled thereby adapted to render said firing circuit closing means ineflective to close the firing circuit as the relay operates.

8. In a mine firing control mechanism, the combination of a sensitive relay adapted to close a pair of contacts as the relay operates, means responsive to a change in the magnetic field adjacent the mine for operating said sensitive relay,

electro-responsive means for resetting said sensi tive relay to a predetermined unoperated condition, a, hydrostat device, a source of electrical energy, means controlled by said hydrostatic device for operatively connecting said electro-responsive resetting means to said electrical source of power thereby to reset said sensitive relay to said predetermined unoperat'ed condition, means for disconnecting said electro-responsive resetting means from said source of electrical power when the sensitive relay has been reset, a time delay relay adapted to be operated by said sensitive relay as the contacts of said sensitive relay are closed, a firing circuit adapted to be closed by said time delay relay after a predetermined period of time has elapsed following the operation of said sensitive relay, a pendulum device having means for closing a control circuit as the pendulum device operates in response to a disturbance of the mine, a slow releasing relay adapted to be operated by the circuit closing means of said pendulum device, a pair of normally closed contacts on said slow releasing relay adapted to interrupt said firing circuit as the slow releasing relay operates, and a pair of normally open contacts on said slow releasing relay adapted to operate said electro-responsive resetting means thereby to maintain said sensitive relay in a, predetermined unoperated condition until the slow releasing relay has released.

9. In a system of the character disclosed for controlling the firing of a submarine mine arranged on the bed of a body of water adjacent the path of travel of a vessel, means including a sensitive relay for detecting a, change in the terrestrial magnetic field adjacent the mine, a mine firing circuit, means controlled by said sensitive relay for closing the mine firing circuit in delayed time relation with respect to said change in the magnetic field, a switch in'said mine firing circuit, and means responsive to a disturbance of the mine for concurrently rendering the sensitive relay ineffective and opening said switch for a predetermined period of time after said disturbance has subsided.

10. In a system of the character disclosed for firing a submarine mine selectively in response to a predetermined change in the magnetic field adjacent thereto, an induction pick-up coil adapted to generate an electrical signal as the number of flux linkages thereof with the magnetic field is varied by a change in said magnetic field, a control circuit, a detecting relay having means adapted to close the control circuit as the detectingrelay operates in response to the electrical signal received from said induction pick-up coil, a relay clock mechanism having a rotatable element adapted to be actuated from an initial position to a predetermined moved position, electro-responsive means operatively connected to said control circuit adapted to actuate said rotatable element from said initial position to the predetermined moved position as the electro-responsive means is energized in response to the closure of said control circuit, a pair of normally open contacts on said relay clock mechanism adapted to be closed when said rointerrupted at the contacts of said detecting relay before the rotatable element thereof is moved to said predetermined position.

11. A mechanism for controlling the firing of a submarine mine comprising a control circuit, a sensitive relay having means for closing the control circuit as the relay operates, detecting erated condition.

means responsive to a change-lathe magnetic field adjacent. the mine adapted to operate said sensitive relay, means controlled by the pressure of the water within which the mine is submerged for operatively connecting said detecting means to the sensitive relay, means for restoringvsaid sensitive relay to an initial unoperated condition within a predetermined period of time after the mine has been launched within a body of water, a time delay'device having an'electromagnet operatively connected to said sensitive relay and adapted to be energized as the sensitive relay operates, means including a. rotatable armature adapted to actuate an escapement mechanism as the electromagnet is energized, a' firing circuit, a source of electrical power, means for connecting said firing circuit to the source of electrical power when said armature has performed a predetermined angular movement in response to the energization of said electromagnet, and means' rupting said firing circuit and concurrently restoring said sensitive relayto said initialv unop- JAIVIES B GLENNON.

H. PARK.