US904918A - Signaling system. - Google Patents

Description

G. BABGOGK. SIGNALING SYSTEM.

APPLICATION FILED MAY 31, 1906.

Patented Nov. 24, 1908.

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hvenlmr" EPPIEDL' IEEIUBUEL mum/ W G. BABOOGK.

SIGNALING SYSTEM.

l v I W APPLICATION FILED MAY 31, 1906.

QQyfip Patented Nov. 24, 1908.

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rs strnrns rArE T ome GARRISON BABcocnoF ROCHESTER, NEW YORK, ASSIGNOR r0 MERTON E. ewis,- or

noorms'rnn,

NEW YORK.

SIGNALING SYSTEM;

Specification of Letters Patent. v

Patented. Nov. 24, 1908.

Application filed May 31, 1906. Serial No. 319,430. I

To all whom 'it may concern:

Be it known that I, GARRISON- BABCOCK,

v In general it may be said-that a system constructed in accordance with my invention provides a construction whereby the 'each of thediiferent ofiicers is, furnished so with a key in which is disposed suitablefire alarm boxes and police si alboxesare' located in a single .circuit an whereby the police'mans numberand the numbe'r' -of the sub-station may be .automatically' tele-, graphed to the central station-.whenthe policeman or watchman opens the=box=-to use the telephone apparatus in ores-rac mmu-nicate with the central station.

My invention provides asystem -whereby mechanism" for bringing about telegraphic communica-tmn w1th the central-statlon, tlus telegraphic communication being in accordance with a predetermined'code and for the purpose of causing the operation at the central station of indicating mechanism whereby the number of the officer maybe recorded. Furthermore, I provide means whereby the number of the sub-station may be automatic ally telegraphed to the, central station and recorded as in the case of the'otlicers number I when the ofiicer opens the box and bringsv into use'the telephone apparatus for the pur-- pose of making therepprt of his beat. My invention willgbe more clearly understood by, referencegfto the accompanying drawings, in which Figure 1 is a diagramnmtic drawing of the circuit arrangement employed.- 4 Fig. 2 is a more or less diagrammatic drawing or the policemans telephonebox, the'cover being removed to illustrate more clearly the mechanismxl sposed therein. Fig. 3is'a; detail view of the policemans box. Fig jisjan el evation View. of; the pblicemans key; part ofthe case being removed to show the interi'or mechanism. Fig. 5 is a section'taken on the line 5, 5 of Fig. 4. Fig. 6 is a detail ,view which will 'be hereinafter described. Fig. 7 is a view taken on the line 7, 7 of Fig. 2.- v Referring now to Fig. 1, I have illustrated a main circuit wire 10 eading from the central station S to a series of fire alarm boxes F, F, F, etc.-and also to a series of police boxes P, P,.P, etc. The tire alarm boxes need not be specifically described in the present application, as their construction is well known to those skilled in the art. I provide .means for interrupting the fire alarm circuit in accordance with a redetermined code, the breaksjn-the-circmt being of different lengths and sequence according to a code emplo by-means of which the circuit. em- -'p1oye at the central station indicates which tot the fire alarm boxes has been manipu- E-lated; The main circuit leads through the mainbattery 11, the fire alarm relay 12 and the police signal relav 13, the circuit being normally closed- Thereby holding the armature's 14 and 15 of the relay 12, and the ar mature 16 of the relay 13 in an attracted position. The relay 12 which may be of considerable impedance, isshunted by the noninductive resistance 17 and controls, by means of its armature15, the local circuit 18. including the source of current 19 and suitable indicating. or recording means 20. The relay 12 and its armature are 50- 51a justed that. an absolute break'in the main circuit. causing; the complete cessation oi the flow of eurrent; will cause the retraction of 'the' armature-1 toclose the local circuit and cause the: opera t'ionof the signaling apparatus '26.. 'A. sli .ht weakening. of the current, however, ue tothe in; clusion: of a resistance in. the-main circuit will not sum-canny denergize' this relay to g2 oceans those portions of the circuit which have so far been referred to, it will be seen that an absolute break in the main circuit, by reason' of the actuation of the mechanism in {any one of the fire alarm boxes will cause the deenergization of the fire alarm relay 12. Upon such deenergization the local circuit 18 will be closed and the indicating or recording means 20 will be operated. This deenergization will also cause the armature 14 to fall back upon the contact 22, thereby closing the local circuit through the winding 18 of the relay 18 and the source ofcurrent 21. The relay 13 thus remains energized 15 and therefore the armature 16 will remain in its attracted position. It is thus apparent that the fire alarm apparatus may be operated without interfering in any way with the policcrecording mechanism at the cen- 20 tral station. The circuit may be interrupted by the make and break mechanism in the fire alarm box in accordance with any predetermined code, whereby the indicating means 20 may indicate the location of thefir'e alarm box which has been manipulated. The armature 16 of the relay 13 is, as has been before stated, normally held attracted by reason of the normally closed main circuit through the relay 13 and through the main battery 11, and is held in this attracted position when an absolute break in the circuit takes place by reason of the closure of the local circuit through the winding 18 and the source of current 21. The apparatus at the sub-station is preferably mounted within the case 22. Hinged at 23 is the door 24,

said door being adapted to be normally held closed by way of the lock 25.

At 26 I have shown a break-wheel for interrupting a shunt circuit, the interruptions being of such a code that they may telegraph to the central station the number of the police box upon the proper operation of the make and break mechanism. shown are the springs 27 and 28, the spring 27 being so controlled by the break-wheel 26 that it'may make and break connection with the spring 28. I provide means whereby this make and break mechanism is set for 29 about which is disposed a coiled sprin 30.

tending to produce a rotation of the shaft in the direction of the arrow 31, the shaft 29 being mounted in the frame piece 29 secured to the box. Keyed upon the shaft 29 is the ratchet wheel 32, which is normally engagedby the pawl 33 upon the break-wheel26 and-- is normally held in such engagement by wayof the spring34. A gear-wheel 35 is also secured to the shaft 29 and mesheswith the M gear-Wheel 36', loosely mounted upon-a shaft Mounted as 37, the shaft 37 being supported by the frame piece 29. Mounted on the shaft 37 is the arm 38 to which is pivoted at 39 the connecting piece 10, this connecting piece being pivoted at 42 to the lug 41 on the box door. The gear 36 is provided with the pin 36' which is adapted for engagement withthe arm 38, as is evident from the drawing.

It is evident, by reference to Fig. 7, that the closing of the door will, by reason of the connecting piece 40 and arm 38, cause a rotation of the shaft 37, and, because of the engagement of the arm 38 with the pin 36], will cause a rotation of the gear 36, in the direction of the arrow 14:. This will cause a rotation of the shaft 29 in the direction of the arrow 45, thereby winding the spring 30. The break-wheel 26 will be heldstationary during this rotation by thestopdti upon the receiver hook 47. Upon the opening of the box door the arm 38 will be removed from engagement with the pin 36', the mechanism, however, being retained by reason of the engagement of the stop 46 with the breakwheel 26. The receiver hook is pivoted at 4S and is associated with a spring 49 tending to raise the same, and it is evident from the drawing that when the receiver 50 is -removed from the hook the stop 46' will be drawn out of engagement with the breakwheel 26, thereby releasing the mechanism and permitting its rotation in the direction of the arrow 31. The slots 51, 51 in the break-wheel 26 form the predetermined code and it is evident thatthe-rotationof thisbreak-wheel will cause the interruption of the circuit at the springs 27 and 28 according to this predetermined code. As I have shown in the drawing, the code is disposed upon the break-wheel so that the number of the sub-station may be telegraphed to the central station during one complete revolu-. tion of the break-wheel 26. In order -.tha t this break-wheel may make but one revolution each time that the door is opened and the receiver is removed from the hook, 1 provide the following construction: At 52 l have shown a pin disposed upon the breakwhcel .26. \Vhen the receiveris removed from the hook, thereby removing the stop 16 from cngagen'ient with the break-wheel the projection upon the receiver hook is lowered so that it is brought into the path of the pin Thus, when the revolution has been 7 practically completed, thefurthcr movement of thebreak-whel 26 is prevented by reason .of the engagement of the. pin 52fwith the projection 53. When thereceiverfis'placed upon .the hook the extens on ,53' is removed from engagementwithithep n 52, whereby .the break-wheel is 'ire'e sto ,move'infthe direction of, the arrow-[31; Th1s movement is,

however, "very slight,= "as,it-.is almost immediately stopped by reason of thereturn lot the stop46 to- .its nomiai position whereby "its the break-wheel is secured against further anism of the lock. Within this extension is mounted the sliding rod57 which is provided at its lower end with the roller 58, this roller being adapted for engagement with the break-wheel 59.; In order to insure constant engagement between the roller 58 and the break-wheel 59, I provide the sliding rod 57 with the collar 60, between which and the key case is disposed the helical spring 61.

The break-wheel is secured to the shaft 60. Mounted in the key case and also mounted upon this shaft is the gear 61 which meshes -with the gear wheel 62, loosely mounted Also upon the row downward pressure upon the shaft 63, and in the brace 64:.

disposed the coiled spring 64 which tends. to produce rotation of the shaft in the direction of the arrow 65. Keyed to this shaft the ratchet wheel 66 which is adapted to be engaged by the pawl 66'. A spring 67 holds the pawl 66 into this engagement. shaft ()3 is secured the arm 67, p'rovidedwith the forked end 68 which is adapted for engagement withthe pin 69 upon the sliding rod 70. mounted in the lugs 71, 71. The sliding rod 70 is provided at its secured in the key case outer end with the finger piece 72 and it is evident that when this rod is pushed inwardly it will cause a rotation of the shaft 63 inthe direction of the arrow 73. This rotation'will wind the spring, back movement of the shaft 63 being prevented by its association with other mechanism as follows: The spring 64 tends to cause rotation of the break-wheel 59 in the direction of the ar- 74. This rotation, however. is normally pretented by-reason of the engagement with a pin 75 upon the break-wheel of the bell cranklevei' 76,- this bell crank lever being pivoted at 76, and normally held in such engagin position by way of the spring 77. The pin 4'5 engages only' that portion of the bell crank lever consistingof the pyoi jection 78 extending downwardly therefronfi This construction is clearly shown in Fig. 6. The arm 77' of the bell crank lever engages at its outer end the head 78 of the sliding pin 79, this pin being mounted in the boss upon the key case. It is evident that a' upon the pin 79 will cause a movement of the bell crank lever 7 6 about the pivot 76,- thus removing the projection 78 from engagement with the 'pin About thisshaft is? ther rotation of the 1'5 and allowing the release of unmask;

Ew-heel. mechanism. I prefer this method of releasing the break-wheel "mechanism because it secures the release at the proper time entirely automatically. hen the key is inserted in the lock of the police box the stud or pin 79 will engage the outer surface of the box and will be forced downwardly thereby securing the release of the breakwheel mechanism as has just been described.

.The break-wheel is to be of such construction that the projections and indentations thereon will cause a movement of the slid-- ing rod 57 corresponding to the number of the watchman or policeman according to any predetermined code. Although it is not essential, I prefer to dispose these projections and indentations upon the break-wheel so that the number of the policeman will be telegraphed to the central station during one complete revolution of the break-wheel. In order that the movement each time that the key is inserted in the lock will be limited to but one revolution, I provide upon the brealv wheel 59 the pin 80, this pin being disposed, as shown in the drawing, at a further distance from the shaft 60' than the pin 75. \Vhen the stud 79 is depressed, thereby a llowing the rotation of the break-wheel, the projection 78 will be brought out of the path of the pin 7 5 and into the path of the pin 80. It is thus evident that when the break'wheel has made practically a complete revolution the pin 80 will engage the 'projection 78', thus causing a halt in the movement of the mechanism. \Vhen the key is withdrawn from the lock the spring 7 7 will .force thebell crank lever out of engagement with this pin 80, thereby allowing the furbreak-wheel 59. This rotation will, however, be almost immediately stopped because the projection 78 has once more been placed in the path of the pin 75. It is thus seen that the mechanism is in position for rewinding. the back move ment being prevented by this engagement. In order that the speed of this mechanism may be governed, I 6-0 the gear-wheel 81 which meshes with the pinion 82, mounted upon the shaft 83.- which in turn is mounted in the key case and in the bearing 84a Upon this shaft 83 is also secured the gear-wheel 85 which meshes with the pinion 86 loosely mounted upon the shaft 60.

Secured to'the pinion 86 is the spring governor 87 and the collar 88. The spring governor engages, as clearly shown in Fig. 5, a groove 89 cut in an extension forming a part of the break-wheel 59. The rotation of the shaft 83 and the consequent rotation of the pinion 86 and the governing mechanism will cause by virtue of centrifugal force, pressure of the collar 90 of the break-wheel 59 against tionalto the speed of .otation of the mechprovide upon the shaft the sleeve 88, this pr ssure being proporanism. Thus the rate of rotation of break-wheel is held constant in a simple a it ettlcient manner. When the key is insertec in the lock the insulated end 91 of the slidin rod 57 engages the contact spring 92 thereby breaking connection between the spring 92 and the spring 93. Since the roller 58 is on the outer periphery of the break-wheel 59, the spring 92 will be broughtinto engagement with the spring 94. A rotation of the break-wheel 59 will secure a series of interruptions of the circuit at the springs 94%- and 92, these interruptions corresponding to the indentations in the periphery of the breakwheel 59, these indentations corresponding to a predetermined code and the number of the watchman or policeman. This making and breaking of the circuit at this point will telegraph to the central station. will be hereinafter described, this watchmans or policemans number while he is opening the box. when the box has been opened and the receiver has been removed from the hook, the make and break mechanism within the box will be released, whereby the box number is telegraphed to the central station. The telephone apparatus, consisting of the ceiver 50 and the-transmitter 95 may then be brought into use whereby the policeman may be enabled to converse with the operator or other person at the central station. These circuit arrangements will be hereinafter described. At 96 I have shown a relay which I find it advantageous to use in this connection, this relay being of particular design, comprising the energizing coil 96, the core 0, bell crank levers d and e pivoted to the ends of the core and pivoted at their elbows at f and g, respectively. A mercury cup h is'suspended from the free ends of the levers and contains the contacts 102 and 103 and mercury 2 The entire apparatus in the.

police box is normally short-circuited, this shunt consisting of the conductor 97, conductor 106 the spring 92, contact 93, conductor 98, contact 99, connector 100 and contact 101, the connector 100 being so disposed upon the door of the box that when it is closed it will electrically connect the contact pieces 99 and 101. This shunt is bridged about the relay 96 which is so constructed and adjusted that it requires a comparatively large current to secure operation while a lesser current will hold it in the operated position. On account of this relay being normally shunted, it is normally inoperative. The contact armature 102 of the relay 96 normally connects with the back contact 103, and when in this inert position effectively shunts the telephone apparatus. The urpose of this construction will hereafter apear. p Normally a circuit is complete throi; ii the fire alarm relay 12, main battery 11, the sensitive winding 17 of the relay 13 winding 113 and the various fire and police boxes. When the otlicers key is inserted into the lock, con nection between the spring 92 and the contact 93 will be broken, thereby breaking the shunt about the relay 96 and allowing the full current to pass through said relay. The relay is then operated, causing the at traction. of the contact armature 102 and the consequent interruption of the shunt about the telephone apparatus. When the otlicers key has been completely inserted and connection between the spring 92 and the spring 94- has been made, a shunt consisting of the conductor 106, spring 92, spring 9st and conductor 107 will be closed about the telephone apparatus. The telephone apparatus consists of the repeating coil 105, the primary winding 104; of which is divided into two parts, the transmitter being connected between the two parts, as indicated in the drawings. The secondary circuit consists of the secondary winding ll l and the receiver 50. 1 bridge the non-inductive resistance 105 about the transmitter 95, in order to insure a path for signaling current even if the transmitter connections be broken. I

The operation of the springs 92 and 94 make and break the shunt about the primary winding 10d and the transmitter 95 and resistance 105, thereby cutting into and out of the circuit the joint resistance of the transmitter and the windings. The resistance of the relay is so adjusted and the relay 13 is so adjusted that when the resistance of the relay 90 is in the circuit containing the fire alarin'relay, the main battery 11, and the winding 17 of the relay 13, the current passint, through the winding 17 will be sufficient to hold the armature 16 in an attracted position; but the adjustment of the relay 13 is such that when the joint resistance of the transmitter 95, winding 105 and the winding 101- is introduced into the circuit-the current passing through this circuit will not be great enoughto sufiiciently energize the relay 13 so as to keep the armature 16 in an attractcdposition. This current, however, is sutlicient to hold the armaturcs of the relay 12 in an attracted position so that this relay will not be in any way affected. It is evident now that if the circuit resistance c0ndition changes at the springs 94 and 92 be made according to some predetermined code a corresponding action of the armature 16 secured. The armature 16 is adapted to open and close a local circuit through a lamp 106, the signal recording device 107 and the current source 21. It is evident, then, that the action of the armature 16 of the relay 13 will cause a corresponding operation of the recording mechanism 107 and a flash of the lamp 1.06. When the main circuit resistance condition changes, whereby the armature 16 of the relay 13 is released,

of the rlay 13 at the central station will be are made in' accordance with some predetermined code, it is evident that the record'- ing device 107 will register such telegraphic message made in accordancewith' the code.

wheel in that particular olicemans key. Each policeman having a; ,iiierent number,

therefore a breakwhee'l of a different code, it is evident that when a policeman unlocks the police box upon his beat the circuit will aver age resistance condition changed by the operation of the mechanism within his key according to the predetermined code whereby his particular number may be tele- .-"graphed to the central station and recorded uponv the recording mechanism 107. In 2 0 order to guard against the withdrawal of the keybefore the closing of the box, whereby the entire apparatus therein would be shortcircuited, I interrupt the circuit at the contacts 99' and 101, this break adapted to be closed whilethe box is closed by the contact spring 100.

After the policemans number has been telegraphed to the centralstation and the box is opened, the policeman, -in order to ,30communicate with the central station, lifts the receiver. 50 from the receiver hook where by, as has heretofore been "explained, the breakwheel 26 is set in motion, the indentalupon this wheel forming a code ac; 3,5 cordingto which the circuit may be sub .to a series of resistance: changes by the operation of spring 27 and contact 28.; Each time spring 27 is disengaged fromlcontact 28 the introduction of the resistance of the transmitter 95, the bridge 105 and primary Y winding 104 williresult, the line current flow being each time reduced to cause re-- traction of the armature l6 of the relay 13 whereby the local circuit through the-lamp 106 and recording, mechanism .107 may be ,closed ,a corresponding nmnberj of, times. The code of the breakwheel 26'is such? that itmay telegraph to the central station-the numberof. the box which has been manipulated. The flashing of the lamp will indicateto theoperator at the central station that an officer has removed the receiver from thehook at the substation. In order that "the-operator may converse with the ofiicer or momma him with any other person in the central station, I provide the cord circuit C. In, order that the operator may connect her telephone, instruments to the line, 1 provide A the jack 108 consisting-of the springs 109 and 110 which terminate in the secondary winding'lll of the induction coil 112,- the primary winding 113 of which is in the main circuit. At't'he substation the receiver of the telephonesetis connectedwith the, secondary winding 11 of the repeating coil zBy atgthe... central station, the telefgraphing of pplicemans number and o s 105. Thefprimary winding 113 is normally shunted so as to exclude its resistance from the circuit while the telegraphing is taking place by the short circuit consisting of the conductor 115, spring 116, spring 117 and conductor 118. When the plug is inserted this ShUIlt'Wlll be brokenby reason of the mechanicalaction between the springs 110 and 117 whereby the winding 113 is brought into use. Simultaneously with this interruption of the shunt about the winding, a

short-circuit is closed about the winding 17 in the main circuit, thus excluding the inductance of the winding 17 from the talking circuit This short-circuit consists of the conductor 118, spring 117, spring 119 and conductor 120. This would manifestly deenergize the relay 17 and cause the retraction of the armature 16 whereby the indicating mechanism of the lamp in the local circuit would operate.

In order that the armature 16 may be held attracted, I provide means for closing the local circuit through the winding 18 and the battery 21 by Way of the conductor 120, spring 119, spring 121 and conductor 122.

this arrangement the winding 18 is energized simultaneously with the establishment of the shunt about the windin 17. Thus the armature 16 is held attracte during the time conversation is being carried on. The ,winding 17 eliminates the necessity of talking through the relay 12. This arrangement enables the operator to converse with'the po- Qliceman over a circuit free from inductance :fand unnecessary resistances. When the con- Zversation has been completed, the receiver is again hung upon its hook, thereby preventing the further operation of themechanism at the substation,

as has been hereinbefore described. The closure of the box door re- Winds the make and break mechanism within the box and also in conjunction with the withdrawal of the key closes the shunt about the apparatus within the box.

It is, of course, desirable that but one police box be in use at a time. In order that a second box cannot be brought into use when one is already in circuit, I so adpist and construct the relay '96 that when it is in the circuit it will not allow the passage of the strong current required to bring about the initial ope'rationof a second relay. The

introduction of a second relay in a circuit will not, however, interfere with the operation of'the relay already in the circuit, since, as has been before stated, the relay can be held in an attracted position by avcu-rrent of considerably less stren' th than. it took to bring about the initia operation. I thus provide a firealarm police signal and tele: phone system'whereby a policeman may unlock thebox and converse with the operator the su tation number being secured entirely automatically.

It is evident that the key containing mech anism for engagement with the springs asso ciated with the box door look, as has heretofore been described, need not be limited to use with. police signal boxes. The key may be one adapted to open ordinary door looks with which are associated the suitable springs to be operated.

lVhile I have herein shown a preferred embodiment and but one application of my invention, it is evident that changes and modifications in construction and a diiferent application could be made by those skilled in the art, without departing from the spirit and scope of my invention. I do not, therefore, wish to be limited to the precise construction and application herein shown and described.

li claim as new and desire to secure by Letters Patent:

1. In an alarm system, a central station, an alarm circuit extending therefrom, a police signal box connected in said circuit, contact springs within said box break-wheel mechanism in said box controlling said contact springs connected with said circuit, means whereby said break-wheel mechanism may be wound by the closing of the box door, telephone apparatus within said box, and means whereby said break-wheel mechanism is released upon the removal ofthe telephone receiver from its hook.

2. In an alarm system, a central station, an alarm circuit, a resistance in said circuit, break-wheel mechanism at the sub-station disposed within a box, contact springs associated with said break wheel mechanism; said. breakwheel mechanism controlling said contact springs which, when operated, close a shunt about said resistance in the circuit, means for winding said break-wheel mechanism upon the closure of the box doors, telephone apparatus within said box, and means whereby the said break-wheel mechanism may be released upon the removal of the telephone receiver from its hook.

3. In an alarm system, a central station, an alarm circuit extending therefrom, a resistance in said circuit, a substation in said alarm circuit, break-wheel. mechanism at the sub-station disposed within a box, contactsprings associated with said break wheel mechanism, said break-wheel mechanism controlling the contact springs which, when operated, close a shunt about the resistance in the circuit, means for winding said breakwheel mechanism upon the closure of the box doors, telephone apparatus within said bo adapted upon actuation to release the wound up brake-wheel mechanism, whereby said contact springs may be operated to in termittently 0 en said shunt about said resistance where y the current in the line may be intermittently decreased and signal receiving mechanism at the central station. adapted to respond to this decrease in current.

at. In an alarm system, a sub-station in an alarm circuit extending from the central station, a resistance in said circuit, said substation consisting of a box, break-wheel mechanism within said box, means for winding said brealcwhecl mechanism upon the closure of the box door, contact springs controlled by said break-wheel mechanism, said contact springs being adapted to open and close a shunt about the resistance in the line. telephone apparatus disposed within said box, means whereby said break-wheel mechanism may be released upon the removal ot the receiver from its book, means for shunting the entire apparatus at the sub-station when the box door is closed, and a relay adapted to open a shunt about. the telephone apparatus upon the opening oi said shunt about the entire apparatus.

In an alarm system, a sub-station in an alarm circuit extending from the central station, a resistance in the circuit, said sub station consisting of a box, break-wheel mechanism within said box, telephone apiaratus within said box, means whereby said break-wheel mechanism may be wound upon the closure of said box and released by the removal of the telephone receiver from its book, a relay vfor controlling a normally closed shunt about said telephone appm ratus, contact springs associated with said ln'cak-wheel mechanism for controlling a. shunt about said resistance in the line, and means whereby a shunt about the entire apparatus within said box may be caused upon the closure of the box door.

6. In an alarm system, a sub-station in an alarm circuit extending from the central station, a resistance in the circuit, said substation consisting of' a box, break-wheel mechanism within said box, telephone apparatus within said box, means whereby said brcak-whccl mechanism may be wound upon the closure of said box and released by the removal of the telephone receiver from its hook,'a relay for controlling a normally closed shunt: about said telephone apparatus, contact springs associated with said break wheel, mechanisn'i "for controlling a shunt about said resistance in the line, means whereby a shunt about the entire apparatus within said box may be caused upon the closure of the box door, locking mechanism for said box, a key for unlocking said box, and springs disposed within said box approximate to the locking mechanism and adapted to be engaged by said key.

7. In an alarm system, a central station, an alarm circuit extending therefrom, a substation in said alarm circuit, said sub-station consisting of a box containing telephone and break-wheel mechanism, contact springs .within said box and disposed near the locking mechanism, a key; adapted to engage said lock ng mechanism, and mechanism within said key associated with said contact springs posed in said box near the locking mechanism,- said contact springs normally closing a shunt about the apparatus withinsaid box and adapted, when operated, to intermittently open a shunt about a resistance in the line whereby the current in said line is reduced, and signal receiving mechanism at the central station adapted to respond to this r duction in current.

9. In an alarm system, the combination of a main circuit, a signal box in the main cir 'cuit. contact prings in the box connected with the circuit, a key for opening the box, signaling mechanism within said key for association with said springs when the key is inserted to lock the box, and means for causing operation of the key mechanism to actuate the springs upon insertion of the key.

10. In an alarmsystem, the combination of a main circuit leading to substations, a

signal box at each substation, signaling apparatus within the box, a lock for the box, switch mechanism within the box near the locking mechanism and connected with the main circuit, a key for cooperating with the locking mechanism to unlock the box and for engaging with the switch mechanism upon insertion in the lock, and mechanism within the key structure for actuating the switch mechanism. 11. In an alarm system, the combination of a main line leading to a plurality ofsubstations, a signal box at each substation for containing the substation signaling apparatus, alock for the box, switch mechanism within the box near the lock and connected with the signaling circuits, actuating mechanism contained within a key structure adapted for connection with the lock to unlock the box, said actuating mechanism being brought into operative engagement with the switch mechanism upon insertion of the key structure in the lock. whereby the circuit conditions will be changed.

In witness whereof, I hereunto subscribe my name this 5th day of April A. D., 1906.

GARRISON BABCOCIC \Vitnesses:

GEO. S. MQMILLAN, E. N. QUINBY.

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