US1921615A - Combined fire and police alarm system - Google Patents

Description

Aug. 8, M GARL I COMBINED FIRE AND POLICE ALARM SYSTEM Filed March 26, 1931 3 Sheets-Sheet l war/74.

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Aug. 8, 1933.

M. GARL COMBINED FIRE AND POLICE ALARM SYSTEM Filed March 26, 1931 3 Sheets-Sheet 2 g] wuwmtoz I fl/mwaus Gmu- Aug. 8, 1933.

M. GARL COMBINED FIRE AND POLICE ALARM SYSTEM 3 Sheets-Sheet 3 Nan/00s GIYRL Filed March 26, 1931 (.1301 net Patented Aug. 8, 1933 UNITED smrss PATEN'T o FIcs COIVIBINED FIRE AND POLICE SYSTEM ALARM Manious Garl, Akron, Ohio; Linnie Ga l, e

trix of said Manious Garl, deceased, assignor to Linnie Garl Application March ZB, 1931. Serial No. 525,510

16 Claims. (01. 179-5)' The combined fire alarm, police signal, and telephone system comprising the present inven tion is primarily adapted for use as a municipal network of communication in the form of a normally charged circuit used in the maintenance of a complete fire and police alarm system to establish intercommunication between the central station of either the fire or police department and their respective outlying stations,

10 field posts or alarm boxes, or to establish selective intercommunication between a series of lice department, is prohibitive in many smaller" 2 cities and especially so in towns and at the present time there are many such cities and towns whose fire and police departments operate at the disadvantage of havingneither a fire alarm system nor a police system.

,The present invention greatly reduces the limitations attendant upon the installation of fire and police alarm systems by providing a three wire, two circuit alarm and communication system in place of the four or six wiresystem ordinarily required in the maintenance of separate police and fire alarm systems. The invention also possesses the added advantage that the two circuits are separately operable to establish signal and telephonic communication through either circuit, or are successively operable from the same outlying station to give alarms to both central stations.

The paramount objectof the inventionbeing economy of installation and maintenance, the l invention is characterized throughout by the use of apparatus of conventional design that may be used either as at present manufactured for separate systems, or may, with slight alterar tions, be converted for use in the improved comibined system. To further the interests of economy of installation and maintenance, the in vention contemplates the use of conventional street alarm boxes, including the usual clock gear train alarm mechanism, in such a manner that the signaling function may be selectively applied either to the fire alarm circuit or to the police alarm circuit. By thus employing one complete operative system of alarm and tele phonic instrumentalities where two wereformerly. required, an added economy of considerable proportions is an embodiment of the invention.

The invention may be briefly described as an alarm system consisting in two or more central stations, or most generally these central stations will consist in a single central station at the fire department headquarters and another central station at the police department headquarters. Each of these central stations for the purpose of description may be said to maintain in the field outlying. stations which maybe widely separated and which may vary in numher. These outlying stations consist in the conventionai street alarm boxes having housed therein alarm and telephonic instrumentalities adapted to function in separate energized circuits connecting each alarm box with the central stationarespectively. Each alarm box is of conventional design and is provided with the usualinner door on which the various instrumentalities, both signal and telephonic, are mounted. The outer door is provided with a shatterable glass seal adapted to be broken in the usual manner when a fire alarm is to-be sent into the fire department headquarters. Means is provided for the use of the alarm box as a field post signal and telephonic station to the police department central stationor headquarters by simply opening the outer door, the signal and telephonic instrumentalities being automatically introduced, upon opening of the outer door, into the police department circuit.

' Provision is made for temporarily shunting the signal and telephonic instrumentalities out .of the fire department circuit to permit the functioning of the fire circuit from other outlying stations to be maintained operable; as usual and to prevent reception of the police signal at the fire department headquarters. -Means is similarly provided for shunting the signal and tele- ;phonic instrumentalities out of the police defor example when a fire is supposed to be of p an incendiary origin, the switch mechanism opapparent as the nature of the invention is better understood, and the same consists in the novel construction, combination and arrangement of parts shown in the accompanying three sheets of drawings, in which Fig. I is a di rainmatic view of the electrical circuits and signal and telephonic instrumeritalh ties of a complete police and fire alarm system installed in'accorcance with the principles of the present invention;

Fig. II is a ront elevation of the clock gear train mechanism with the inner door removed, showing the same in normal position when the outer door is shut and when the mechanism is ready to be tripped to send in a fire alarm.

Fig. III is a fragmentary view, similar to Fig.

II, showing the clock gear train mechanism in the position occupied when the police alarm lever has oee tripped and when the outer door open to shunt the signal and telephonic instrumentalities out of the fire department circuit and install the same into the police depart ment circuit.

} Fig. IV is a fragmentary view similar to Figures II and III, showing the clock gear mechanism occupying the proper position after a fire alarm has sent in to the fire department headquarters, with the out r shut and before the clock mechanism has been reset by the presiding officer of the fire patrol.

Fig. V is a fragmentary side elevation of the arrangement or" parts shown in Fig. IV.

Fig. VI is a front elevation of the detached inner door panel showing the signal and telephonic instrumentalities mounted thereon.

VII is an underneath view of the showing in Fig. VI.

Fig. VIII is a fragmentary front elevation of an alarm box having hinged inner and outerdoor panels with associated signal'and telephonic instrumentalities mounted. thereon in operative relation.

Fig. IX is a side elevation of a transfer switch employed in connection with the present invention showing the same in its operative position when the outer door is closed to permit the ringing in of a fire alarm to the fire alarm headquarters;

Fig. X is a side elevation of the transfer switch taken at right angles to the showing in Fig. I I;

Fig. XI is an end view of the transfer switch in the position shown in Fig. IX;

Fig. XII is a side elevation of the transfer switch showing the same in position for police and telephone signal service;

Fig; XIII is a side elevation of the transfer switch." This view is taken at right angles to the showing of Fig. XII; and

Fig. XIV is a fragmentary view of a door shunt employed in connection with the present invention.

In all of the above described views like characters of reference are employed to designate like parts throughout.

Referring now to Fig. 1, unit 1 designates diagrammatically the police department headquarters central station including a police alarm relay 10, a telephone unit'll in multiple therewith, and an energizing battery 12, all operatively connected in a three wire police department circuit 13 connected with various outlying stations or field posts.

Unit 2 represents diagrammatically a similar central station for the fire department, including a fire alarm relay 14, telephone instrumentalities 15 in multiple therewith and an energizing battery 16, all operatively associated in the fire department circuit 17.

Unit 3 represents diagrammatically the signal and telephonic instrumentalities operatively mounted wthin one of the outlying street alarm. boxes as connected in the police department circuit and including clock controlled signal instrumentalities 18, telephonic instrumentalites 19, a clock shunt machanism 20, and a transfer switch 21 for shunting the signal and telephonic 'instrumentalities out of the police department circuit.

Unit 4; representsdiagrammatically the same outlying station'represented by unit 3, with the signal and telephonic instrumentalities ponn-ected n thefire department circuit 17, and showing a telephone signal switch 22 adapted for use in'establishing telephonic communication with the central station of the fire department.

Referring now to Figs. VI, VII and VIII, the alarm box is shown at 23. This box is of the conventional type and has hinged thereto as at 24 an inner door panel 25 on which are mounted the signal and telephonic 'instrumentalities. Hinged to the alarm box 23, as at 26, is an outer door panel 27 having a shatterable window 27 which is shown in its open position in Fig. VIII.

The signal instr'umentalites shown at 18 in units 3 and 4 of Fig. I and in Fig. VII are comprised of a clock unit 28 secured by means of bolts 29 (see Fig. VIII) to the rear of the panel 25. This clock unit comprises a police alarm wind and trip lever 30 positioned on the front of the panel 25, and a fire alarm trip lever 31 operable by means of a handle 31 and extending forwardly of the panel 25.

The telephonic instrumentalities 19 are com-- Operatively associated with the inner door panel 25 is a transfer switch 21 for selectively rendering the signal and telephonic instrumentaltles 18 and 19 operable in the fire department or police department circuits 13 or 17. This switch isoperable by a plunger 38 extending outwardly of the front wall of the panel 25 for such selective control. The switch in its normal position with the outer door panel 2'] closed serves to maintain the signal and telephonic instrumentalities in the fire department circuit, but upon opening of the outerdoor panel this switch is automatically operable, by an arrangement of parts more fully to be described hereinafter, to exclude these instrumentalities from the fire department circuit and install the same in the police department circuit.

The telephone signal switch 22 is operable by a push pull plunger 39 extend ng forwardly of the-panel 25 to causes. signal appartus (not shown) at the fire department headquarters to notify the desk attendant that the telephone is to be used. 4

Referring now to Figs. II, III, IV and V, the gear clock signal unit 28 is shown in a number of operative positions. The specificspring actuated gear train which causes movement of the novel signal control is of conventional design;

No claim is made to the novelty of this mecha nism, the novelty of the .clock unit residing ratherin the signal control itself. The clock unit isshown as comprising the usual frame 40 including a plate 4l. Journalled in this plate 41 is a shaft 42 upon which the wind lever 30 is mounted and secured. This shaft 42 has applied thereto a torque normallyurging the same in a counter-clockwise direction. The shaft 42 has keyed thereto a swingarm 43 having oppositely extending radial portions. 44 and 45, the arm 44 being'slightly longer than the arm 45. The arm 45 is provided with an abutment surface 46 adapted to engage the pin 47 on a sliding plate 48. The plate 48 is'provided with a slot 49 through which there extends a screw 50 'which is threadedly receivable in the plate 41.

The plate 48 is of elongated shape and one end thereof has a roller 51 mounted thereon, which roller is formed of insulating material. to a post 52 and electrically connected thereto is a conducting leaf spring 53 having one end thereof bearing against the roller 51 as at 54 and normally urging the roller and the elongated plate 48, to which it is attached, down wardly in a direction opposed to the direction of movement of the plate as urged by the engagement surface 46 bearing against the pin 47. In the normal position of the arm 43 the abutment surface 46 bears against the pin 47 and holds the plate 48 in the position shown in Fig. II' with the leaf spring 53 under tension. A bar 54 formed ofsuitable insulating material is secured by insulated bolts 55 to? the plate 41. This bar 54 has .a contact plate 56 secured thereto, which plate is connected through an electrical connection in the form of a copper strip 57 to a contact post 58 (Fig. II and units 3 and 4 of FigJI), electrically connected to one contact 59 of the circuit breaker mechanism 60. The contact post 58 isalsoelectrically'connected to the transfer switch 21in a manner to be more fully described; The post 52 which has the leaf spring 53 secured thereto is electrically connected to themovable arm 61 "of the telephone receiver hook 32. This post 52 is also electrically connected to the other contact 62 of the circuit breaker mechanism 60. (See unit 3, Fig. I.) theroller 51 maintains the clock shunt, comprised of the contact plate 56 and the leaf spring 53,'closed in order. to shunt the telephone mechanism out of the circuit. Upon tripping of the circuit breaker mechanism in a manner to be more fully described, the clock shunt is opened to enter the telephone mechanism into the circuit for operative use after the signalha's'been given. The clock shunt isoperable in this manner to exclude or include the. telephone mechanism in this circuit regardless 'of whether the telephone mechanism is' tripped for signalling in either the police department or the fire de-- outer door. 27 closed and with the trip arm 43 bearing against the pin 47, andwith the clock Secured In the normal position of the mechanism" shunt closed t'o-e'x'clud'e the telephone mechanism from, the fire, department circuit and to include. the signal mechanism in the alarm circuit, open-x ing of the door 27 will cause the transferswitch 21 to shunt the fire department circuit completely out of the box and introduce the police department circuit tothe various signal and telephonic devices thus far described within the box. -By turning the wind lever 30 in a clockwise direction,.-as shown in Fig. VIII, the shaft 42 will be turned against the torque applied to it by the clock spring mechanism. This will cause the swingarm 43 to be turned in the direction of the arrow'sho'wn in Fig- II, the limit of this turning movement being shown in Fig. III with the swing arm 43bearing against 'the stop pin 63. .Upon releasing of the wind lever 30 the escapement mechanism 64 will be set into action and the swing arm 43 will be rotated in a counter clockwise direction. The turning of the swing arm 43 in a clockwise direction will cause the sliding plate 48 to be moved downwardly against the action of the contact'sprin'g 53 to open the clockshunt 20 andexclude' the telephone mechanism from the police department circuit maintained within the box by virtue of the outer door ZF-being opened. Due tothe turning of the swing arm 43 under the action of the clock spring working on the shaft 42, and due to the operation of the escapement mechanism, thesignal mechanism 60 (shown in Fig. VI) will beset into motion.

, The signal mechanism comprises a. rotatable. disk 67 having -a number of spaced radial pro-v jections 65 thereon adapted to successively en'- of Fig. I); Engagement of the projections 65 with this trip member 66 will cause opening and closing of the contact members 59 and 62 (see; unit 3, Fig. I) to carry the signal through the police departmentv circuit 13 to the police department headquarters. i

It will be seen, therefore, that when theouterdoor is open and when the wind lever 30 is rotated until the swing'arm 43 engages the stop ,63 and is then released the signal mechanism is operated in "the police department circuit. The

45 engages the pin 47, thereby closing the shunt 20 and throwing the telephone mechanism into gage a trip member 66 (see Fig. VII and unit 3 the police circuit; from which it was. previously j excluded to permit tripping and functioning of the signal apparatus in the police circuit.

It has'been seen-how the signalling mechanism 18 functions to cause a signal to be sent.

into police headquarters when the outer door is" opened and; when the wind arm 30 is set off. It has also been seen howthe clock shunt 20 operates to permit this'tripmechanism to function for signal purposes and later to permit'the telephonemechanism to be used after the signalling has ceased, and itywill nowbedescribed how the trip handle 31 maybe employed to send a signal caused by the signal mechanism 18 throughthe fire department circuit-to the fire department headquarters. With the trans fer switch 21 so positioned that the fire depart ment circuit is introduced into the boxand; the

various signal and telephonic instrumentalities adapted for use in the fire department circuit, means is provided whereby movement of. the trip arm handle 31 in an arcuate slot-68 formed in the inner door 25 will release'the swing, arm 43 for further rotational movement throughout a wider arc than is permitted whenthe trip arm 30 is thrown. Thus the escapement mechanism 64, released upon movement 'of the swing arm 43,.willpermit the circuit breaker disk 67 to make several revolutions to send in several series of signals to the fire department headquarters. To accomplish this the trip lever 31 is provided with a bifurcated end 69 and is pivoted at 76 to the inside of the inner door panel 25. The bifurcations of the end 69 straddle the pins 47 and movement of .the lever 31 on its pivotal axis and through asmall angle commensurate with movement of the trip handle 31 in the slot 68 will shift the pin 47 (see Fig. II). from the-short arm 45 or" the swing arm 43, thereby leaving the swing arm free to rotate under the action of the coil spring of the clockmechanism as governed by the escapement mechanism 64. The long arm 43 may then swing in a counter-clockwise direction from the position shown in Fig. II to the position shown in Fig. IV. During movement of the swing arm 43 the escapement mechanism 64: is in operation. .A locking means is provided for the escapement mechanism in the form of'a pivoted latch member 73, (see Figs. II, III, IV, and V). This latch member is substantially triangular in shape and is provided with an offset flange 74. A pin 75 extends completely through the latch member adjacent one corner and a leaf, spring 76 secured to a post 77 has a bearing surface 78 thereon normally resting on the. pin '15 in the position shown in Fig. III. The long end 44 of the swing arm 43 is provided with'a projection 79 (see IV) which engages the offset portion 74 of the latch member 73 upon completion of the stroke of the swing arm when tripped by the trip lever handle 31'. 'The'play aiforded by the slot 49 in the sliding plate 48 per mits the projection 79 to engage the ofiset por tion Hand by a bell crank lever action through the pin 75 in the latch member '73 toward the escapement mechanism 8 (see Fig. V), to stop the escapernent of the clock mechanism and to stop movement of the breaker disk thereby shuttingoff the signal. As the long end 44 of the swing i3 engages the pin 47 at the end of 7 its stroke, the slidingplate 48 is' carried up wardly, together withthe roller 51 thereon, and the clock shunt 2G is closed to shunt the signal mechanism, which has'completed itsfunction,

' so shown as being in series in the fire depart rem the circuit and. introduce the telephone mechanism. In unit 4; of Fig. I thesignal switch ment circuit l7. This switch is of the push pull type and upon outward pulling of the plunger 39 the circuit is broken and a signal device at the fire department headquarters is operated; -This signal device may be. of any suitable type,

. I the switch is shown as being capable of shunting either the firealarm circuit or the police alarm circuit, including both signal and telephonic instrumentalities, from the box. The contact fingers 81 are electrically connected in the fire alarm circuit. The bar 82 is adapted to short circuit the two contact fingers 81 when the outer door of the box is opened. The contact switch handles shown in Fig. IX at Sis adapted to be engaged by the outer door 27 and compressed uponclosing of the outer 'door tothrow the switch to the position shown in Unit 4. The fire alarm circuit is entirely shunted out or" the box as shown in unit 3 but a continuous path is-farmed keeping the fire alarm circuit closed, since the contact fingers 81 remain on the contact bar 83 until after contact is made with the bar 82. A pair of contact fingers84 remain at all times in contact with.

the contact bar 83. ."These latter contact fingers 84 are connected electrically to the signal trans,- mitti'ng and telephone circuit. It willithus be seen that when the contact fingers 81. are in contact with the bar 82 the fire alarm circuit.

paratus, and the switch introduces the police alarm circuitin the box in proper position for the transmission of police signals and telephonic communication with the police headquarters. When theouter door is closed and the contact switch handle S is depressed thereby, the con-' tact bars 85 make contact with the bar 86 to completely shunt the police alarm circuit from the box and connect the fire alarm circuit with the signal and telephonic instrumentalities in the box. It should be remembered, however, that in order for telephonic,communication'to be had with the firedepartment headquarters the fireman at. the box must, after opening'the outer door, depress the contact switch handle S manually to shunt the police department cir cuit out of the boxand introduce the fire department circuit. He -must also operate the signal switchfii) in the manner previously described to get the operators attention at his headquarters.

In'Figs. VIII and XIV a door'shunt is shown comprising contact elements 90 and 91 operatively connected in the telephone circuit The outer dooris provided with a'contact 92 adapt-- ed to bridge the contacts 90 and 91 to shunt the telephonic instrumentalities out of the fire department circuit when the outer door is closed. The electrical connections for this door shunt are'such that the signal instrumentalities remain in the circuit whether the door shunt is open or closed. It is thought unnecessary to illustrate the complete electrical connections for this door'shunt.

The operation of the combined police and fire alarm system will be apparent from theforegoing description, inasmuch as the various .elements, units and combinations of units have been described both as to their structure and as to their operation singly and in combination with each other where the occasion required.

The inventionis not to be limited to :the

exact arrangement of parts shown in the accompanying drawings and' described in the specification, as. various...changes in the detail of constructionmay be resorted to without departing from the spirit of the invention. Only in ,sofar as the invention has been particularly pointed out in the xacccmpanying'claims is the same to be limited. 1 7

Having thus' described my invention, what I claim as new and desire to secure by Letters Patent in the United States, is:

1. In a combined fire alarm and police alarm system, a central fire station, a central police station, an alarm box, a normally closed circuit connecting said alarm box with the central fire station, a normally closed circuit connecting said alarm box with the central police station, signal instrumentalities and telephonic instrumentalities in each alarm box adapted to be selectively introduced into either the fire circuit or the police circuit, and'a transfer switch for causing selective introduction of the. signal instrumentalities and the telephonic instrumentalities into either circuit.

i 2; In a combined fire alarm and police'alarm system, a fire station," a police station, an alarm box having a normally closed door; a normally closed circuit connecting the alarm box with the A causing'selective introduction of the signal in--'.

strumentalities and the telephonic instrumentalities'into either circuit, said transfer switch being operable upon opening of thedoor to exclude the signal instrumentalities and the telephonic instrumentalities from the fire circuit and introducethe same into the police circuit,

and being operable upon closing of the door. to

exclude said instrumentalities'from the police:

circuit and introduce the same into the'fire circuit. 1 i A 3. In a combined fire alarm and police alarm system, ,a central fire station, a central. police station, a plurality of alarm boxes, a normally closed circuit connecting each alarm box with the central fire station, a normally closedcircuit connecting each alarm box with the central police station, signal instrumentalities in each alarm box adapted to be selectively introduced into either circuit; and a transfer'swi'tch in each alarm box for. causing selective introduction of thesignal instrumentalities intoeither circuit.

4. In a combined fire alarm and police alarm system, a central fire station. a central police station, a plurality of alarm boxes, a normally closed circuit connecting each alarm box with the central firestation, a normally closed circuit connecting each alarm box with the central powire system, and instrumentalities associated with said circuit for selectively permitting communication between any one of the outlyingstations and any .one of the central stations.

. 6; In a combined firealarm and police alarm system; a central fire station and a central policestation, an alarm box havinga normally closed door, a normally closed circuit connecting :the alarm .box with. the'central fire station, a

normally closed circuit connecting the alarmbox with'the central police station, communication instrumentalities in said "alarm. box adapted to be selectively introduced into either the fire circuit or the police circuit, and a, transfer'switch in the alarm box for causing such selective inlice station, an. alarm .box, a normally closed circuit connectingthe alarm box with the cen' tral fire station, a normally, closed circuit connecting the alarm box with the, central police station, communication. instrumentalities in said alarm box adapted to be selectively introduced into either the fire circuit or the police circuit, and atransfer switch inthe alarm box for causing such selective introduction of the communi-;v

cation instrumentalities into either circuit.

8. In a dual alarm system, a pair of central stations, an outlying station, a normally closed three wire circuit. connecting the outlying station with'each central station, signal instrfu-.

mentalities and telephonic instrumentalities'at said outlying stations, and means for selectively introducing said instrumentalities into the circuit leading to eitherstation.

9..An alarm boxfor use incommunication circuits for police andfire departments, having a normally closed door, 'signal'instrumentalities in said alarm .boX,- a normally'inaccessible trip for the signal'instrumentalities adapted to be ties to perform aipredetermined function at ,the police departmentga normally accessible: trip for. the signal instrumentalities adapted to cause the same toperformja predeterminedfunction necting said alarm box with the police station;

signal instrumentalities and telephonic instrumentalities in said. alarm box .adapted. to ,be' selectively introduced into either ,thefire circuit. orthe police circuit, a transfer switch in the alarm boxfor. causing selective introduction 1 of the signal instrumentalities and the 'telephonic instrumentalities into either circuit, said transfer switchbeing operable upon opening of the door to exclude the signal instrumentalities and the telephonic instrumentalities from the 1 fire circuit and introduce thesame into the police circuit and being operable uponclosing of the door to exclude said instrumentalities from the police circuit and introduce the same into the fire circuit, and a door shuntnormally 1-15 rendered accessible upon opening of the door a and adapted to cause the signal instrumentali mally closed doors therefor, a normally closed circuit connecting each alarm box with the central fire station, a normally closed circuit connecting each alarmbox with the central police station, signal instrumentalities and telephonic instrumentalities in each alarm box adapted to 'be selectively introduced into either the fire circuit or the police circuit, a transfer switch in each alarm box for causing selective introduction of the signal instrumentalities and the telephonic instrumentalities mounted therein into either circuit, each transfer switchbeing op erable upon opening of the door of therespective box in which it'is mounted to exclude the signal instrumentalities and the telephonic instrumentalities from the fire circuit and introduce said instrumentalities into the police circuit and being operable upon closing of the door to exclude said instrumentalities from the police circuit and introduce the same into the fire circuit, a clock for operating each set of signal instrumentalities, a normally inaccessible trip for the respective signal instrumentalities in each box adapted to be rendered accessibleupon opening of the respective door and adapted to cause the signal instrumentalitiesto send in. a sig-' nal through the police circuit to the central police station, and a'norrnally accessible trip for the respective signal instrumentalities in each box adapted to cause thesignal instrumentalities tosend in repeated signals through the fire circuit 1 to the central fire station.

12. An alarm box having a normally closed door andhaving signal instrumentalities therein, a clock for operating said signal instrumentalities, a normally inaccessible trip for the si nal instrumentalities adapted to be rendered accessible upon opening of the door and adapted to cause the signal instrumentalities to send a signal through an electric circuit, and a normally accessible trip for the signal instrumen talities adapted to cause the same to send a signalthrough an electric circuit.

13. In a combined fire alarm and police alarm system, a fire station, a police station, an alarm box having a normally closed door, a normally closed circuit connecting the alarm box with the fire station, anormally closed circuit connecting said alarm box with the police station, signal instrumentalities andtelephonic instrumentalities in s id alarm box adapted to be selectively introduced into either the fire circuit or the police circuit, a transfer switch in thealarm 7 switch being operable upon opening of the door to exclude the signal instrumentalities and the telephonic instrumentalities from the fire cir-' cuit and introduce the same into the police circuit and being operable-upon closing of the door to exclude said instrumentalities from the police circuit and introduce the same intothe fire circuit, a door shunt normally-excluding the tele-' phonic instrumentalities from'either circuit but operable upon opening of the door to introduce the same into the circuit'for which the transfer switch-is set, a clock for operating said signal instrumentalities, a normally inaccessible trip for the signal instrumentalities adapted to be rendered accessible upon opening of the door adapted'to operate in either circuit and being normally operable in the fire circuit but adapted 7 upon opening of said door to operate inthe police circuit.

15. In a combined fire alarm and police alarm system, a fire station, a police station, an alarm box having a. normally closed door, a circuit connecting the alarm box with the fire station, a circuit connecting the alarm box with the police station, signal instrumentalities and telephonic instrumentalities in said alarm box adapted to be operated in either circuit for communication with the respective stations, and a transfer switch in the alarm box operable upon cpeningof the door to cause selective introduction of the signal instrumentalities and the telephonic instrumentalities into either circuit, said transfer switch being accessible upon opening of the door for manual operation. 1

16. In a combined fire alarm and police alarm system, a fire station, a police station, an alarm box having a normally, closed door, a circuit connecting the alarm box with the fire station, a circuit connecting the alarm box with the police station, signal instrumentalities and telephonic instrumentalities in said, alarm box adapted to be operated in either circuit for communication with the respective stations, a transfer switch in the alarm box operable upon opening of the door to cause selective introduction of the signal instrumentalities and the telephonic instrumentalities into either circuit, said transfer switch being accessible upon opening of the door for manual operation, and a door shunt normally excluding the telephonic instrumentalities from either circuitv but operable upon opening of the door to introduce the same into'the circuit for which it is set.

MANIOUS GARL.

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