US1399760A - Fire-alarm system - Google Patents

Description

M. GARL.

FIRE ALARM SYSTEM. APPLICATION FILED AUG.20, 1920.

1,399,760. Patented Dec.13, 1921.,

4 SHEETS-SHEET I Tifil.

witness M. GARL.

FIRE ALARM SYSTEM. APPLICATION FILED AUG-'20, 1920. 1,399,760. Patented Deu.13,1921. a 4 SHEETS-SHEET 2. u

Swan/1am manz'ozos fiari/ m. I hm. Z A .5 ma sm \w v km W N Witt woo M. GARL.

FIRE ALARM SYSTEM. APPLICATION FILED AUG.20, I920.

Patented Dec. 13, 1921.

4 SHEETS-SHEET 3- M. GARL.

Patented Dec. 13, 1921.

4 SHEETS-SHEET 4.

FIRE ALARM SYSTEM. APPLICATION FILED AUG.20, 1920. 1,399,760.

X [M3 ma g i l-la. a9 .68 1 g I 7 IMAM Mel MANIEUUS lfirlltli, 01E AltIllUN, Ulilllll.

Specification of Letters Patent.

lt 'atented Dec. 13, ltlWl.

Original application filed May 123, i917, serial lilo. teaser, Patent 1%. 1,363,2l -6, dated December 2%,

1920. Divided and this application filed .llugust 120, 18:30.

To all whom it may comer 1t:

Be it known that l, ltlANIOUS GARL, a citizen of the United States, residing at Akron, in the county of tiummit and bltate o'l @hio, have invented certain new and useful improvements in Fire-Alarm Elystems, ot which the following a specification.

The present invention relates to improvements in lire alarm and other systems which employ a number of instruments adapted to transmit signals to a central or other receiving station, and this a division of my co-pendinp; application for lire alarm sy tem, @erial No. 169,567, filed May 18, 1917,

Among the objects of the invention is to,

provide a system of this character which has a normally closed llne Cll'Clllt which not dependent upon utilising the earth or ground as a part oil? such circuit; and to provide a telephone having means for conat iurther object of the invention is to provide a means whereby a brealr in the line circuit oil? the system may be easily and quickly located to enable the necessary re pair tohe promptly made, and pending such repair, the system will he in operative conclition, using); the ground temporarily as a part oil? its circuit.

l l ith these and other objects is view, the invention consists in, certain combinations, arrangements, and associations of the parts, as will more fully appear as the description proceeds, the novel features thereof being, minted out in the claims. V For a -lull. understanding; of the invention, rclerence to be had to the following; des ,ription and acconmanying drawings, in which Figure l is a front elevation, partly in section, of an instrument embodying the pesent invention, the instrument being adapted for use in connection with a tire alarm system.

Fig. 2 is a rear elevation of the instrument shown in Fig, 1.

Fig. 3 represents a section on the line 3-3 of 2, looking in the direction of the arrow.

l ig. 4t represents a section on the line l-4 oit' Fig. 1.

5 is a bottom plan of the instrument shown in llig. 2.

Fig. 6 is a detail view, partly in section, showing the circuit controlling device or breaker embodying the present invention.

Fig. 7 represents a central axial section through the circuit controller or breaker.

Figs. 8 and 9 represent sections on the line t5-8 oll ig. 2, the releasing lever for the instrument being shown in two different positions in these views.

.l ig". 10 is a diagram showing a lire alarm system having two instruments connected therein, the diagram also showing; the tele phone adapted to be connected in series in the tire alarm system; and

Figs. ii and 12 are detail perspective views showing, respectively, the telephone jaclr and plug for one oi the boxes or instruments.

Similar parts are designated by the same reference characters in the several views.

"The present invention is applicable generally to tire alarm telegraph systems or other electric systems which comprise a mher c signal-transmitting instruments and a central or other station for receiving the signals from the ditl erent instruments. lln systems at this character, and especially in lire alarm telegraph systems. it is oi great importance that certainty and reliability in the transmission of the signals be insured at all times. lthas been found, however, from experience, that the ordinary open or exposed contacts, such as those employed in the usual fire alarm systems, are corroded or otherwise attached by gases, this bein par ticularly the case with instruments installed in rubber factories and other places where the cr. ntacts are subject to the correcting; intluence of sulfur V Corrosion of the electrical contacts of the instruments prevents proper engagement or electrical con ductivity between the contacts, and when that occurs, the instrument and, in some cases, the entire system, is rendered inopen at'ive. it has also been found that where the tire alarm system utilizes the earth or ground as a part of its operative circuit, the system is liable to damage and to interference with its operation should the line wire of the system come in contact with the overhead or line wire of another electrical system, it being common in some localities to employ the earth or ground as the return part of the circuit of various electrical systems, and contact between the line wire of the fire alarm system and the line wire of one of the other systems would result in the flow of electric current fromthe other system over the fire alarm system;

These difiiculties are avoided by the present invention, the preferred embodiment of which is shown in the accompanying drawings and will be hereinafter described as applied to a fire alarm system. It is to be understood, however, that the invention is not restricted to the precise construction and arrangement shown, as equivalent constructions are contemplated and will be included within the scope of the claims.

In the present instance, wherein the invention is shown applied to a fire alarm system, each instrument is preferably fitted into a suitable box 1 which may be of metal mounted on or attached to a post or pipe 2, the box being preferably grounded with the post or pipe 2. A door 3 serves to close the, front of the boz; and it may have a glass or other breakable panel 4 through which the releasing member of the instrument may be reached for manipulation without the necessity of opening the door, although the door may be opened by an attendant for inspection, repair or other purposes. The instrument, which is preferably mounted in the upper part of the box 1, has its parts supported on a base 5 which is preferably grounded with the box, and a front plate 6 is mounted on the base plate 5. The circuit controller of the instrument comprises a disk 7 of hard rubber or other insulating material which is mounted to turn with an operating shaft 8, and the disk 7 has pins or teeth 9 projecting from its periphery, the number and arrangement of the pins corresponding to the number of the particular instrument. For example, the pins are grouped to repre sent. the number 151, it being understood that the number and arrangement of the pins on the different instruments in the system will be grouped in diflerent ways so that each instrument will have its individual number. A casing 10 of suitable insulating material is secured to the front of the plate 6, the casing having a rear wall 11 which'closes it, and a glass 12is adapted to close the front of the casing, this glass being removably held in place by a screw cap 13. The casing is preferably round, or

, substantially so, and it is provided at the bottom with partitions 14L and 15 of insulating material, these partitions subdividing the bottom of the casing to form wells 16 and 17, and these wells contain bodies of mercury. Metallic conducting strips 18 and 19 are arranged in the bottoms of the wells 16 and 17, these strips being preferably co-cxtensivc with the bottoms of the wells and presenting relatively large areas of contact with the bodies of mercury, thus insuring the flow of current between the strips and the bodies of mercury with-a minimum resistance. A bindingpost or terminal 20 extends through the wall of the casing above the level of the mercury baths and is connected to the conducting strip 18. A hollow terminal 21 also extends through the wall of the casing above the level of the mercury baths and is connected to the conducting strip 19. A circuit controller 22 is provided to establish and to break the circuit between the conduct ng; strips 18 and 19. Preferably, and as shown, the circuit controller is yoke-shaped, it having a pair of arms 23 and 21 which are arranged to operate in the wells 16 and 17 respectively. The circuit controller is pivoted to rock freely on a pivot pin 25, gravity serving to move the arms 23 and 2t dovmwardly so that the lower ends normally rest on the conducting strips 18 and 15), and the intermediate portion 26 of the circuit controller is in the path of the pins or projections 9 whereby rotation of the wheel or disk 7 in the direction of the arrow in Fig. 6 causes the pins to successively cooperate with the circuit controller to lift the latter into the dotted line position and clear of the bodies of mercury in the baths 1G and 17 and as each pin passes the intermediate portion 26 of the circuit controller, the latter drops by gravity to the full line position where the lower ends of its arms 23 and 24 engage the conducting strips 18 and .19. Ohviously, when the circuit controller is elevated by each pin, the circuit between the conducting strips 18 and 19 is ln'okcn. whereas when the circuit controller is in its lower position, the circuit controller establishes electrical connection between the conducting strips 18 and 19. The pivot pin on which the circuit controller rocks is carried by a suitable bracket 27, the latter being secured within the casing 10 by a binding screw 28. In the ordinary operation of the instrument, the circuit controller is actuated by the pins 9 of the breaker wheel, but on some occasions it is desirable to manipulate the contro ler manually to send special signals over the system. In order to provide for such manual manipulation of the circuit controller. a plunger 29 may be employed, this plunger consisting preferably of a metallic rod which extends through the hollow binding post 21 and having a button 30 on its outer end for manipulation by the finger, and the inner end of the plunger having a head 31 arranged to cooperate with the under side of the circuit controller 22 whereby inward pressure of the plunger will manually raise the breaker sufficiently high to break the circuit between the conducting strips 18 and 19. A spring 32 serves to normally hold the plunger in inoperative position where it will not :interfere with the automatic operation of the circuit controller, and an insulating bushing 33 serves to limit the out ward movement of the plunger under the action of the spring 32.

The breaker wheel 7 which is rotated by the shaft 8 may be actuated by any suitable means such, for example, as the ordinary clock motor. As shown, the clock. motorv comprises a drum 3 1;, preferably of insulating material and mounted to turn with a shaft 35, the latter being journaled in the front plate 6 and in the rear plate 36. A wire or cord 37 is wound upon the drum 3 1 and has an actuating weight 38 attached thereto. The shaft 35 which carries the drum 3 1 has a gear wheel 39 mounted loosely thereon, and this gear wheel adapted to be connected to the shaft 35 by a ratchet and pawl device d0 whereby rotation of the shaft 35 under the action of the weight 38 will cause rotation of the gear wheel 39, but rotation of the shaft 35 in a reverse direction which will lift the weight will be permitted by the ratchet and pawl device while the gear wheel 39 remains motionless. A cord or wire 11 which is also wound on the drum 3 1 serves to rotate the drum 3 1 in a reverse direction for the purpose of raising or resetting the weight 38. The gear wheel 39 cooperates with a pinion 4-2, this pinion be ing lined. to the shaft 8' which carries the breaker wheel, and by this arrangement, rotation of the gear wheel 39 under the influence of the weight 38 will cause rotation of the breaker wheel. The ratio of the gear wheel 39 and the pinion 1 2 may be varied, but it is generally preferable to employ a ratio whereby the breaker wheel shaft 3 will revolve four times to one revolution of the shaft 35. In order to control'the speed of rotation of the breaker wheel, an escapement 4-3 is provided, this escapement being mounted on a rock shaft 44 and 00-. operating with an escapement wheel 4.5, the latter being mounted on a shaft 416 and carrying a pinion 17 which cooperates with a gear wheel 48 on the breaker wheel shaft The multiplying gearing between the shaft 8 and the shaft 16 enables the vibratory escape/merit to retard to the proper dethe speed of rotation of the breaker wheel. A weight 49 is fixed to the escapement shaft 44 and serves to retard the vibration of the escapement.

The shaft 35, which grounded, is, connected to a disk 50 of brass or other suitable conducting material. This disk 50 is secured to the rear face of the drum 3-1 and a portion 51 of its periphery is raised so as to project beyond the circumference of the drum 3%, while the remaining portion 52 of its periphery is of less diameter than the drum 34: and below the periphery thereof. A spring or brush 53 is arranged to ride upon the raised portion 51 of the disk 50 or upon the periphery of the insulating drum 34L during a revolution of the shaft 35. This spring or brush is insulated from the base plate 5 by an insulating support 54, and the spring or brush is connected by a binding post 55 and a conductor 56 to a binding post 57, the latter extending through the front plate 6 to the front thereof and being connected by a conductor 58 to the binding post 28, the binding post 57 being insulated from the grounded plate 6. Under normal conditions, the weight 38 is in elevated position, as shown in Figs. 2 and 3. In order to retain the weight in such position but to permit its release and cause operation of the instrument, a circumferentially grooved plug 59 is attached to the weight or to the cord 37, and the base plate 5 is formed with a, keyhole aperture 60. ,A. lever 61 is also pivoted at 62 to the under side of the base plate, and this lever has an aperture63 therein which is sufliciently large to permit the passage of the plug therethrough. When the weight in its normal elevated position and the plug 59 is fully raised, the lever 61 occupies the full line position shown in Fig. 5 and thus serves to retain the grooved portion of the plug 59. in the narower portion of i the keyhole slot 60 in the base plate 5, the weight 38 being thereby supported in its elevated position, but when the lever 61 is swung into the dotted line position shown in Fig. 5, the plug 59 is moved into the larger end of the keyhole slot 60 and the plug may then pass downwardly through the plate 5 and the lever 61, and the weight 38 is then free to drop, the drum 3 thereby actuating the breaker wheel. The weight rewinding cord 41 may extend downwardly through a bushing- 64 in the base plate 5 and it may be provided at its lower end with a button or handle (55 by means of which. it may be pulled downwardly to rewind or reset the weight after the instrument has been operated. The lever 61 is preferably provided with a handle 66 at its forward end, and this handle may be arranged immediately within the glass or other panel 4 so that when the panel l hasbeen broken or removed, the handle 66 may be easily reached for manipulation.

A pair of line terminal posts 67 and 68 is provided, these terminal posts being insulated from the base plate 5 by insulating bushings 69 and 70, and the post 67 is connected to a binding post 71 which is also insulated from the base plate 5 by an insulating strip 72, tie binding post 71 being connected by a conductor 73 to a binding post 74, the latter being fitted into but insulated from he front plate 6. The binding post 74 extends to the front of the late 6 and it is connected by a conductor 7 o to the terminal or binding post 21. A strip 76 of insulating material is provided on the upper side of the base plate 5, and a conductor strip 77 overlies the insulating strip 76 and is connected to the terminal post 68. The conductor strip 77' is connected to a. binding post 7 8 which is fitted in but insulated from the front plate 6, this binding'post 7 8 being connected by a conductor 79 to the terminal 20. Each box or instrument is provided with a telephone jack which is bridged across the line terminals 67 and 68 whereby a telephone may be introduced into the line circuit of the system, the snunt r bridge circuit of the telephone jack being open uncer normal conditions when the telephone is not in use. The telephone jack may be made in diilerent ways. As shown, the conductor strip 77 provides one terminal or contact 80, and a plate 81 connected to the terminal 67 provides the cooperating terminal or contact 82, the front plate 6 being provided with a socket 83 through which the telephone plug may be inserted, and the telephone jack is in position to cooperate with the respective terminals of the telephone plug when the latter is inserted into the socket. The telephone may be made in different ways, although it is preterable to use a telephone plug of a type similar to that commonly used in connection with telephone systems. The plug shown in the present instance in Fig. 12 comprises a handle 84 having a conducting sleeve 85 projecting forwardly therefrom to a point near its end, an insulating bushing 86 which is fitted within the conducting sleeve, and a central or inner terminal or electrode 87, the wires 88 and 59 of the telephone being connected, respectively, to the conducting sleeve 85 and the inner terminal 87, and when the plug is inserted into its socket, the conducting sleeve 85 will contact with the terminal 80 ofthe jack, while the inner terminal 87 of the plug will contact with the terminal 82 of the jack. When the plug is introduced into the jacir, the telephone at y the boxer instrument is introduced into the fire alarm system in shunt therewith. According to the present invention, a telephone is also provided for the central or receiving station, this telephone embodying the usual transmitter 90 and receiver 91 and, in addition, a local battery 92, the transmitter and battery of the telephone being connected in series with one another, and when the telephone plug isinserted in the telephone jack at central station, the local battery of the telephone will be connected in series with the battery or source of energy for the fire alarm system, thus overcoming the resistance oiiered by the relay 105 in the system at the central station.

As shown in Fig. 10, a telephone jark .l is provided at the central station which is adapted to receive a telephone plug P ol the central station telephone, the jack J having its terminals connected in series with the line wire 103, and a circuit closer It arranged in shunt with the jack serves to complete the line circuit when the telephone is not in use. Preferably, and as shown, a spherical head 93 is provided which is adapted to enter between and to connect the terminals of the circuilt closer K while the telephone plug is not in position, this head being carried on an arm 94 which latter is pivoted at 95 to a suitable support 96. lVilh this arrangement, the l ead 93 will normally connect the terminals of the circuit closer K, but when the telephone is used, this head i il is disengaged from the circuit closer K alter the telephone plug has been inserted, the telephone being connected in series with the fire alarm system and thereby completing the circuit of such system.

Preferably, and as shown, a key 97 is provided for a purpose that will hereinafter appear, this key comprising a spring which is secured at one end and electrically connected to the line terminal (33, and its opposite end is normally adjacent to but separated from the under side oi the base plate 5, upward pressure on the fl'tt! end of the key, however, serving to en; it with the base plate, thereby grounomp; the side of the system to which the terminal 68 is connected.

A fire ala 'm system embodying the present invention and having a plurality oi instruments connected therein is shown diagrammatically in Fig. 10. In this diagram, A and B designate, generally, two of the instruments of the system, C represents diagrammatically the central or receiving: station, and T and T represent diagrammatically telephones adapted to be introduced into the system at a box or instrument and at the central station, respectively. The circuit of the system, including the various instruments, is normally closed and receives energy from a main battery 15, one terminal of this battery being connected by a conductor 98 to one blade 99 of a double switch S. A conductor 100 leads from the contact 101. of the switch 8 to the box A through which the circuit of the system is normally closed, and a conductor 102 leads from the box A to the box or instrument B, this conductor ill?) leading to the line terminal (ill, the conductor 77 leading from the terminal cs to the binding post 78, this binding post being congrounding nected by the conductor 79 to the terminal 20 oithe circuit controller. The terminal 20 is connected to the conducting plate 18 submerged in the body oi? mercury in the well 16, and the other conducting plate 19 submerged in the body of mercury in the well 1? is connected to the binding post 21. The binding post 21 is connected by the conductor to the binding-post 7 1, and the latter is connected by the conductor 73 to the line terminal 67. The line wire 103 leads from the line terminal 07 to such other instruments as may be included in the system, through the circuit closer it, and it terminates at the line terminal 101 of the relay 105, the latter being located at the central or receiving station. The other line terminal of the relay is connected by the conductor 10? to the opposite terminal oi the main battery B. The instrument 1% is adapted to be connected to the ground G through the frame or metallic parts of the instrument which is designated diagrammatically in Fig. 10 as a conductor 108 which leads to the shalt 35, the ground connection when completed being made through the disk 50, the brush or spring contact 53, the conductor 50, bimling post 57, conductor 58, and the terminat28, the latter being electrically connected to the circuit breaker The instrument it is provided with a ground G" which corresponds to the ground (l of the instrument ll. A. main ground (1' is provided for the system, but this ground normally not used. To enable the system to be grounded when such is desirable, the ground conductor 109 leads to a contact 110 which is adapted to be engaged by the blade 99 01' the switch S9, when this switch. is shifted into the dotted line position shown in Fig. 10, one terminal 01 the battery 13 being then grounded through the conductor 98. An additional conductor 111 may also be extended from the line terminal 104,- of the relay to the other blade 112 01* the switch S, this blade of the switch being connected. by the member 113 to the blade 99 whereliiy these blades will move in unison, and when the switch ii is in its normal position, the conductor 111 will not be included in the system, but when the switch '5 is sliiitted to the dotted line position in l? 10, the conductor 111 will be connected through the terminal 101 to the line wire 100. The local terminal 11 1 oil the relay is connected to one terminal of a local battery B while the other local terminal 115 of the relay may be connected to the conductors 110 and 117 which are connected respectively to a bell 110 and a suitable register or indicator 119, the other terminals 120 and 121 of the bell and register respectively being connected by a conductor 122 to the other side of the local battery B The local cirelb cuit olf the relay oi. a type Whereby the bell, register, or other indicators or instruments connected therein will be caused to act when the normally closed line circuit of the relay is broken, it being understood that the line circuit of the system is normally closed. The telephone at the central station, according to the present invention, is introduced in series in the line circuit of the system, and, furthermore, the polarity of the telephone battery 92 is such in relation to the main battery 13 of the system that the positive side of the battery 92 will be connected to the negative side of the main battery B, that is to say, the telephone battery 92 is connected in series with the main battery B whereby the telephone battery 92 will supplement the energy supplied to the system by the main battery.

In order to provide for operation of the system using the ground as a return, a second relay 123 is preteral'ily used at the central station, themain circuit terminal 124 of which is connected by a conductor 125 to the local circuit terminal 115 of the relay and the other main circuit terminal 126 of which is connected to a contact 127 of a switch S, the blade 128 01 this switch being connected to the conductor 122 leading from the positive side the local battery B 01'' the relay 105, and the blade 129 of the switch- S is connected by a conductor 130 to the local terminal 181 of the relay 123, the other local terminal 132 of the relay 123 being connected by a conductor to the positive side of a local battery B and the other side of 100 this local battery being connected to the local terminal 115 of the relay 105.

By using a second relay connected as de scribed, the bell and register will act in the same way when the ground is used for the 05 return of the main line system as they act when the all-metallic line is used, in View of the following mode of operation Z-VVllGIl the line circuit of the system is broken, the local circuit of relay 105 will be closed. By shifting the switch S from the full line to the dotted line position (Fig. 10), the main circuit of relay 123 is introduced into the local circuit of relay 105 and the local circuit of relay 128 will then be open. Any signal or alarm coming over the system from an instrument connected therein will then cause the bell and register to operate in response to the signal just as the relay 105 would cause operation of the bell and signal in the normal condition 01 the system.

The operation of the system may be described, briefly, as followsz-llormally, the switches S and S occupy the positions shown by the full lines in Fig. 10, and hence the main battery of the system will not be grounded, and the actuating weights of the various instruments in the system will be in elevated position and retained in such posi tion by the releasing lei er 0101 each instru ment. Also, the toothed wheel 7, of each instrument will occupy such a position relatively to its respective circuit breaker 22 that, upon the commencement of the rotation of the toothed. wheel,- the circuit break e will begin its operation of sending an alarm or signal corresponding to the number of the particular instrument. While the instruments are inactive, as is normally the case, the circuit is normall closed throughout the system as follows: tarting with the main battery B, the current passes over the conductor 98, the switch blade 99, conductor 100, through the instrument A, overthe line conductor 102, terminal 68, conductor 77 to binding post 78, over the conductor 79 to terminal 20 to the conducting plate 18 submerged in the mercury in the well 16, thence up the arm 23 of the circuit breaker 22, thence down the arm 24-v of the circuit breaker to the conducting plate 19 submerged in the mercury contained in the well 17, thence to the terminal 21, over the conductor to the binding post 74 thence over the conductor 73 to the binding post 67, thence over the line conductor 103 and the circuit closer K therein to the line terminal 10%- of the relay through the line circuit of the relay to the line terminal 106 of the relay, and thence by the conductor 10? to the return side of the main ba tery B. In order to send a signal or alarm from any instrument, it is only necessary to break or remove the panel At of the particular box or instrument and then push the handle 66 of the lever 61 toward the left in Fig. 1. This operation releases the plug 59 attached to the weight cord 37 and the weight 38 then acts upon the drum 34 to rotate the shaft 35. Motion from the shaft 35 is transmitted to the shaft 8, and the toothed wheel 7 is thereby caused to revolve. During the revolving motion of the toothed wheel 7, the teeth or pins 9 thereon successively engage and lift the circuit breaker 22 to the dotted line position shown in Fig. 6, each pin after passing the circuit breaker permitting the latter to drop by gravity to its normal lower position, as shown by the full lines in Fig. 6. The lifting of the circuit breaker by each pin causes the arms 23 and 24 of the circuit breaker to disengage from the conducting strips 18and 19 and to lift clear of the bodies of mercury contained in the wells 16 and 17. Continuity of the circuit between the terminals 20 and 21 is thereby broken each time the circuit breaker is acted on by one of the pins or teeth, and this breaking by the circuit breaker of this instrument and the re-closing of the circuit between the breaks actuates the relay 105, causing the signals or indicators contained in the local circuit thereof to respond to the signal transmitted from the instrument.

After the sending of the signal from the instrument has been completed, the normally closed line circuit of the system is restored and any other instrument in the system may be similarly set into operation. In the normal condition of each instrument, there is no ground connection with any of the instruments, as the brush or spring contact 53 of each instrument normally rests on the insulating drum 34;. However, upon the releasing of the instrument, the grounding disk 50 of the instrument comes into engagement with the brush or spring contact 53, and a ground connection is then established for the instrument in operation, the ground being completed from the terminal 20 through the circuit breaker 22, the terminal 28, conductor 58, binding post 57, conductor 56, the spring contact 53, the disk 50, and the frame of the instrument which is indicated diagrammatically in Fig. 10 as the conductor 108.

By moving the switches S and S, which are located at the central or receiving station, to the dotted line positions, the main battery B will be grounded at one side, and

a signal could be obtained from the instrument using the ground as one side or a part of the circuit, thus enabling the instrument to transmit a signal in the event that the line circuit of the system is broken or is undergoing repairs. In such case, the current would pass from the main battery 13' over conductor 98, switch blade 99, contact 110 and conductor 109 to the ground (11, thence from the ground G of the instrument B over the conductor 108, shaft 35, disk 50, brush or contact 53, conductor 56, bind ing post 57, conductor 58, terminal 28, the circuit breaker 22, the conducting strip or plate 19, terminal 21, conductor 75, binding post 7 1, conductor 73, through the terminals 67 and and over the line wire 103 to the terminal 101 of the relay, through the line circuit of the relay 105 to the line terminal thereof, thence over the conductor 107 to the return side of the battery. Such would be the operation it the line circuit were broken at the point X between the i11- struments A and B and a signa were sent from the instrument B. If the break occurred at the same point as before, but in strumcnt A were set into operation, the cm rent from the main battery 13 would pass. as before, to ground G, thence from ground G to instrument A, thence through the grounding and circuit breaking devices oi that instrument to the line wire 100 returning through the wire 111 and the relay to the return side of the batter It will be understood that a break in the all-metallic line of the system will be indicated at the central station by the register 119, and the attendant will then shift the switches S and S to their dotted line positions (Fig. 10) pending repair of the line.

l'Vhile the main line system is grounded,

and the switch S occupies the dotted line position (Fig. 10), the bell and register which are then connected in the local circuit oi? the relay 123 will respond to the signals or alarms coming over the line in the same manner that these devices respond to such signals when the all-metallic line of the system is unbroken. and the bell and register are controlled by the relay 105'.

The key or plunger 29 may be used by the lire department OfllClitl or other attendant as a means for manually sending a special signal or alarm over the system, in which case the circuit controller 22 would be caused to rise and fall manually to break and reestablish the line circuit, the signal being sentovcr the line in a manner similar to that where the signal is transmitted automatically by operation of the signal wheel 7. The key 29 is also used to send a prearranged signal over the line from any instrument or lOOX to the central station to notify the central station operator that it is desired. to use a telephone on the line. In using a telephone on the line, the attendant at the box or instrument inserts his telephone plug into the ack 83, thus bridging the terminals of this telephone over the line terminals 67 and 68, and the central station operator inserts the plug of his telephone into the jack J and opens the circuit closer K. The key 29 is then pressed up to complete the line circuit through the telephone at the instrument, and the key is held up while the telephone is in use. When the telephones are to be removed from the system, the pressure uponthe key 29 is released, allowing the circuit controller 22 to complete the line circuit, and the telephone plug at the instrument is removed from its jack and the central station operator closes the circuit closer K and then removes the plug of the telephone at the central station from its jack J The grounding key 97 may also be used to send a special signal over the sys torn from the respective instrument or box, while the switch S is in the dotted line position (Fig. 10), and this key may also be used in testing the system.

By providing a circuit controller having its contacts submerged in baths of mercury, the engaging surfaces of such contacts are, under ordinary conditions, covered and protested from the corroding influences of gases and other elements which, it has been "found, attack the ordinary exposed contacts as heretofore used and thereby render the operation of a system of this character uncertain and hence unreliable. Therefore, certainty and reliability in the operation of the system is insured by providing, at all times, good conductivity between the Working or signaling contacts. This result is attained by the present invention and yet operating movement of the Working contact is not impeded, as the mercury offers negligible resistance to the movement of the working contact.

By providing a normally closed circuit system which, under. ordinary conditions, operates without a ground return to its main battery or source oi. energy, there is practically no opportunity for damage to or interference with the operation of the systcm by crossing oi its wires with those of other circuits. Furthermore, by connecting the telephone in series in the line circuit or the system, satisfactory use may be made of the telephone, as compared with such systems which employ a ground return, for, in such latter systems, interference by other circuits using ground returns impairs or prevents the use of a telephone.

The novel features of the circuit breaker are claimed in my co-pending application to which reference has been made, the claims of the present application being based upon the alarm system.

Having thus described the invention, what I claim as new and desire to secure by Let tors Patent is 1. In an alarm system, the combination with a normally closed main line circuit, of a series oi? mechanical circuit breakers interposed inv the closed circuit at diiierent stations therein and each including a movable contact making element, a signal operable by the breaking of the closed circuit by the circuit breaker at any one of the stations, a loop connection adapted to be introduced into the main line closed circuit at any one of the stations, and manual means associated with each of the circuit breakers for temporarily moving the contact making element thereof into an open position to render the loop connection operative, the circuit breaker automatically resuming an operative position as soon as the manual means is released.

2. In an alarm system, the combination with a normally closed main line circuit, of a series of mechanical circuit breakers, interposed in the closed circuit and each in cluding a movable contact making element, a signal operable by the breaking of the closed circuit by the circuit breaker at any one of the several stations, a telephone connection at each or the stations, a separable telephone adapted to be connected at the telephone connection of any of the stations and thereby introduced into the closed circuit, and manual means associated with each of the mechanical circuit breakers for temporarily moving the contact making element thereof into an open position to render the telephone connection operative, the circuit breaker automatically resuming an operative position as soon as the manual means is released.

3. In an alarm mechanism, the combine tion With a normally closed main line circuit, of a. series of mechanical circuit breakers interposed in the closed circuit and each including a movable contact making element, a signal located at the central station and operable when the closed circuit is broken by the circuit breaker at any one of the stations, a telephone connection at each of the stations, a separable telephone adapted to be connected in at the telephone connection of any of the stations and thereby in troduced into the closed circuit, manual means associated with each of the mechanical circuit breakers for temporarily moving the contact making element thereof into an open position to render the telephone connection operative, a central station telephone adapted to be cut into the main line circuit, and a c rcuit closer in shunt with the central statlon telephone and adapted to close the main line circuit when the telephone is not in use.

4. In an alarm system, the combination with a normally closed circuit, of a series of mechanical circuit breakers interposed in the closed circuit at different stations and each including a movably mounted contact making element which-normally tends to assume a closed position, a signal at a central station operable by the breaking of the closed circuit by the circuit breaker at any one of the stations, manual means associated With each of the clrcuit breakers for temporarily moving the contact making element into an open position, said contact making element immediately returning to a closed position as soon as it is released, a telephone connection at each of the stations, a separable telephone adapted to be attached at any one of the telephone connections and thereby introduced into the main closed circuit, the telephone being rendered operative by the manual moving of the contact making element into an open position, and a corresponding telephone connection adapted to be introduced into the main line circuit at the central station.

5. In an alarm system. the combination with a normally closed circuit, of a series of mechanical circuit breakers interposed in the circuit at difi' erent stations and each including a movable contact making element, a signal located at a central station and operable by the breaking of the closed circuit by any one of the circuit breakers, a spring retracted manually operable member associated with each of the circuit breakers for temporarily moving the contact making element thereof into open position, the contact making element immediately returning to a closed position as soon as the manually operated member is released, a telephone connection at each of the stations, a telephone adapted to be attached at any one of the telephone connections and thereby introduced into the main closed circuit, the telephone being rendered operative by the manual movement of the contact making element into open circuit position, and a corresponding telephone connection adapted to be introduced into the main circuit at the central station.

In testimony whereof I affix my signature.

MANIOUS GARL.

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