US807235A - Alarm and telephone system. - Google Patents

Description

No. 807,235. PATENTED DEC. 12, 1905.

G. BABGOGK.

ALARM AND TELEPHONE SYSTEM. APPLICATION FILED DEO.14,1903.

Inv EnTnr Anurngg UNITED STATES PATENT OFFICE.

GARRISON BABCOOK, OF CHICAGO, ILLINOIS.

TALARIVI AND TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Dec. 12, 1905.

Application filed December 14, 1903. Serial No. 185,090.

To aZZ whom it may concern.-

Be it known that I, GARRISON BABOOCK, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Alarm and Telephone Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to a combined telephone and alarm system, and has for its object the adaptation of a single line for the transmission of telephonic signals and other sigilalS, such as fire-alarm, police-alarm, and the ike.

In the drawing I have shown a single line 1, connected with a central exchange 2 and adapted for transmitting signals from firealarm stations, such as shown at 3, or policecode apparatus (shown at 4) and from telephonic apparatus, (shown at 5.) All this apparatus is normally included serially in a closed circuit with a battery 6. A relay 7 is also included serially in said circuit and upon deenergization is adapted to open and close a local alarm-circuit 8, which may include a source of current 9 and receiving or recording apparatus 10. A winding 11 of a relay 12 and the winding 13 of a .relay 14 are also included in the circuit 1. The winding 13 and the winding of the relay 7 are so adjust: ed that the circuit therethrough must practically be broken before the relays are sufficiently weakened to release their armatures. At the fire-alarm station 3 I have shown an apparatus containing box 15, the cover 16 thereof when closed serving to close a line through a contact-piece 17, extending across line-terminals 18 19. The contact-piece 17 and bridge-contact pieces 20 20 are secured to the cover, and as the cover is opened the contact-piece 17 is withdrawn from the terminal contacts 18 and 19 and the bridge-contacts 20 are carried to span between the contacts 18 and 19 and other contacts 21 21, connected with line-breaking mechanism 22, which consists of .a spring-driven break-wheel 23, engaged by a contact 24 to open and close the circuit, as well known in the art.

As the break mechanism at any fire-alarm box connected with the line is actuated the corresponding signal will be manifestedby the recording apparatus 10, actuated by the relay 7, the following circuit existingfthrough said relay: from the battery 6 through the relay 7, parallelly through the windings 11 of relay 12 and winding 13 of relay 14 to conductor 25, conductor 26, jack-springs '27 28-120 cone ductor 29, conductor 30, through closing-contact 17 at thepolice-alarm stations, through the break mechanism 22 at the actuated firealarm station, and back to the battery 6. The other signalreceiving apparatus at the central exchange will not be affected by the actuation of a fire-alarmbox, as will be hereinafter more fully described.

The code apparatus 4 and the telephone apparatus 5 may be contained in the same switchbox or may be disposed in separate switchboxes. In the drawing, as shown, they are disposed in the same switch-box 31, the cover of the box being opened to adapt the code apparatus 4 or telephonic apparatus 5 for inclusion in the circuit 1. If it is desired to send a code-signal to the central exchange, a lever 32 is actuated to successively engage con: tacts 33, each alternate contact being connected with a resistance 34, and as the lever travels over these contacts, which are of various lengths to give the proper code-signal, the line is alternately directly closed and caused to include the resistance 34. When the lever, engages a contact connected with the resistance 34, a circuit will be established as fol-, lows: from the battery 6 through relay 7, parallelly through the winding 11 of the relay 12, winding 13 of relay 14, conductor 25,

will serve to weaken the relay sufficiently to release its armature 38 to engage the contact 39 to close a local circuit traced as follows: from the armature 38, through jack- springs 40 and 41, through a lamp or other indicating-signal 42, through an alarm-circuit-controlling electromagnet 43, a battery 44, and through a recording apparatus controlling electromagnet 45 back to the armature 38.

As the re:

As the arm 32 engages alternate contacts the i,

local circuit containing the armature 38 will be alternately closed to flutter the indicatinglamp 42 and also to record the proper codesignal on the recording device 46. This interrupted glow of the lamp 42 indicates to thedoperator that a code device is being actuate As the windings l1 and 13 are included parallelly in circuit when a fire-alarm signal is sent to the line, the tendency would be to release the armature 38 to close the local circuit and to actuate the recording mechanism 46 as the circuit is opened through the main line. To prevent such actuation, I provide an additional winding 47 for the relay 12, which winding is adapted for inclusion in a local circuit with the armature 48 of the relay 14, which circuit may be traced as follows: from the armature 48, through the conductor 49, battery 44, conductor 50, additional winding 47, conductor 51, back to armature 48. Upon a break in the main circuit due to actuation of the fire-alarm apparatus the armature 48 will be released to close the local circuit just traced, and the winding 47 will energize the relay 12 to prevent release of the armature 38, which would otherwise happen, due to the sensitiveness of the winding 11. Thus fire-alarm signals and signals from the code apparatus will be received at the central exchange independently of each other.

When it is desired to have telephonic conversation with the central operator, the re ceiver 52 is removed from the hook 36, and instead of the main circuit being closed directly through the switch-hook an impedance or resistance 53 anda transmitter 54 are included in circuit in place thereof. The insertion of this resistance again causes sufiicient weakening of the relay 12 to close the local circuit containing the recording apparatus 46; but the indicating-signal 42 at the central exchange instead of fluttering will be constant, to notify the operator that telephonic connection is desired, and the operator thereupon inserts a plug 55, connected with a cord-circuit 56, into the spring-jack, asshown in dotted lines. She thereby closes a secondary circuit traced as follows: from the tip 57 of the plug to the tip-spring 58, conductor 59, through the secondary winding 60 of the repeating-coil 61, through the conductor 62, sleeve-spring 63 to the sleeve 64 of the plug, and through the operators apparatus 65, which may be connected with the plug by the actuation of the key 66. The telephonic apparatus at the calling-station is included in the primary circuit traced as follows: from the battery 6, through the condenser 67 which shunts the relay 7, through conductor 68, jackspring 69, jack-spring 27 conductor 70, primary winding 71 of the repeating-coil 61, conductor 30, bridge-contact 20, conductor 35, then parallelly through the circuit containing the receiver 52. and a condenser 5.3, and

through the circuit containing the transmitter 54 and impedance 53 to the arm 32, conductor 37, the other bridge-contact 20, back to the battery 6, and conversation between the substation and the central operator may be carried on. It will be noticed that conductor 68 shunts the windings of the relays 12 and 14, thus removing all impedance due to said windings from the circuit, the condenser 67 also removing impedance due tothe relay 7.

I thus provide a system in which a single line is adapted to transmit telephonic signals, fire-alarm signals, and police-signals, and any number of stations may be connected with the line, each signal-receiving apparatus at the central exchange operating independently of the other and each giving a positive signal to the central attendant of the class of substation apparatus actuated.

I do not wish to be limited to the exact arrangement of apparatus and circuits, as changes therein may readily be made without departing from the scope or spirit of the invention. v

I claim as new and desire to secure by Letters Patent 1. In a combination telephone and alarm system, the combination with a normally closed main circuit leading to a central exchange, of alarm apparatus and telephonic apparatus included in said circuit, a source of current in said circuit, independent indicating means at the central exchange for said alarm apparatus and said telephonic apparatus and means for preventing actuation of either of .said indicating means upon actuation of the other.

2. In an alarm-circuit, the combination with a normally closed main circuit leading to a central exchange, of a plurality of substations adapted to be serially connected in said circuit, means at some of said substations for repeatedly opening said normally closed circuit, a relay at the said exchange adapted to actuate alarm apparatus at each opening of the line, means at some of the other substations for intermittently including a resistance in said normally closed circuit, a second relay at the central exchange adapted to actuate signaling apparatus at each inclusion of said resistance in said circuit, and means for causing the said alarm apparatus and said indicating apparatus to be actuated each without actuation of the other.

3. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a sensitive relay included serially in said circuit and responsive to slight resistance changes in said circuit, an additional relay in said circuit responsive only to comparatively great resistance change in said circuit and means for preventing actuation of said sensitive relay upon actuation of said additional relay.

4. In alarm system, the combination with comes a normally closed circuit, of a source of current .forthe'saidcircuit, a plurality of substationslinsaidcircuit, means at one of said substations'for repeatedly opening saidnormally closed circuit, a relay in said circuit adapted to actuate alarm apparatus as .said line. is opened, means at anothersubstation for repeatedly including resistance in said circuit, an additional relay in said circuit adapted to actuate indicating mechanism when said resistance is included in said circuit, and means for preventing actuation of said second relay when said line is opened.

r 5; In'an alarm system, the combination with a normally closed main. circuit leading to a central exchange, of a plurality of substations adapted for inclusion in said line, a source of current in said circuit, a relay included seri-e ally in said main circuit, a local alarm-circuit controlled by said relay, means at one of said substations for repeatedly opening said line, whereby alarm apparatus in said alarm-circuit is repeatedly actuated, an additional relay included serially in said main circuit, a local indicating circuit including the armature of said additional relay, means at one of said substations for repeatedly including resistance in said main circuit, whereby said additional relay is actuated to cause the actuation of indicating devices included in said indicating-cincuit, and means for preventing actuation of saidI second relay when said first relay is actuate i 6. Juan alarm system, the combination with a normally closed .main circuit leading to a central exchange, of a plurality of substations includediin" said circuit, .a source of current in said circuit, a relay in said circuit, a local alarm-circuiticontrolled by said relay, means at one of the substations for repeatedly opening said main circuit to cause said relay to repeatedly open said local alarm-circuit, a second relay in said main circuit, a local indicating-circuit including the armature of said second relay, said second relay being normally sufliciently energized to. attract its armature to open said local indicating-circuit, means at one of said substations for repeatedly including-resistance.insaid main circuit, whereby said second relay isweakened to release its armature to closesaid local indicator-circuit, an additional winding for said second relay, and means for closing a local circuit through said second Winding upon the actuation of said alarm-controlling relay, whereby said second relay is prevented from releasing its armature to close said local indicating-circuit.

7. In an alarm system,.the combination with a normally closed main circuit, of a plurality of substations included in said circuit, asource of current-in said circuit, a relay in said circuit, a local alarm-circuit controlled by said relay, means at one of'said substations for repeatedly opening said. main circuit, whereby said-relayis deenergized to allowopening of said alarm-circuit, whereby alarm apparatus is actuated, a second relay in said circuit,'a local indicating-circuit including the armature of said second relay, said armaturebeing normally attracted .by said second relay to open, said indicating-circuit, means at one of said substations for repeatedly including resistance in said main circuit, whereby said second relay is weakened to release its armature to close said indicating-circuit, a third relay included in said main circuitya local circuit including the armature of said third relay,said armature being normally attracted by said third relay to open said local circuit, and an additional winding for said second relay included in said localcircuit, the opening of said main circuit causing deenergization of said third relay to releaseits armature to close the local circuit containing said armature and said additional winding for said second relay, whereby said second relay is prevented from releasing its armature to close the indicating-circuit.

8. In a combined alarm and telephone sys. tem, the combination with anormally closed main circuitleading to a central exchange, of alarm apparatus and telephone apparatus adapted for connection in said main circuit, a source of current in said circuit, a relay in said circuit, alarm apparatuscontrolled by said relay, means at one-of said substations for repeatedly opening said main circuit to cause the alarm apparatus to be actuated, a' second relay in said circuit, an indicating local circuit controlled by said second relay and including indicating devices, resistance adapted for inclusion in the'said main'circuit upon actuationof said telephone apparatus, the inclus sion of said resistance causing said second relay to be weakened .tovallow closure of said indicating-circuit, whereby said indicating devices are actuated, and means for preventing the operation of either of said relays upon ace tuation of the other. i

9. In a combined telephone and alarm system, the combination with a normally closed main circuit leading to a central exchange, of a plurality of substationsconnected with said circuit, a-sourcewof. current in saidcircuit, means atone'of said substations for repeatedly including resistance in said main circuit, a relay at the central exchange, an indicating-i circuit controlled by said relay and including indicating devices, repeated inclusion of said resistance in said circuit causing repeated ac= tuation of said relay to repeatedly close-said indicating-circuit to repeatedly actuatesaid indicating devices, telephonic apparatus atone of said substations, the actuation of said telephonic apparatus causing resistance to be continuously included in said circuit, Whereby said relay is continuously actuated to cause. continued closure of said indicating-circuit-to cause continued actuation of said indicating devices, recording mechanism included in said local indicating-circuit adapted to be actuated upon repeated inclusion of resistance in said circuit and telephonic apparatus at the central exchange, connection of said central telephone apparatus with the circuit causing said indicating device to become inert.

10. In a combined telephone and alarm system, the combination with a normally closed main circuit leading toa central exchange, of a spring-jack and cord connecting apparatus at the central exchange, a plurality of substations and a source of current included in the said main circuit, a relay in said main circuit, a local alarm-circuit controlled by said relay, means at one of said substations for repeatedly opening said main circuit, whereby said relay allows the actuation of alarm apparatus in said local alarm-circuit, a second relay in said circuit, an indicating local circuit. including the armature of said second relay, said armature being normally attracted by said second relay to open said indicatingcircuit, means at one of said substations for repeatedly including resistance in said main circuit, whereby said second relay is weakened to allow closure of said indicating-circuit, means for preventing actuation of said second relay upon opening of said main circuit, telephonic apparatus at one of said substations, resistance adapted upon the actuation of said telephonic apparatus to be continuously included in said main circuit, whereby said second relay is continuously actuated to allow continued closure of said indicatingcircuit, indicating devices in said indicatingcircuit,v said indicating devices being intermittently actuated upon the repeated inclusion of resistance in said circuit, the actuation of said indicating devices being continued upon an actuation of said telephone apparatus, and means upon the insertion of a plug in said spring-jack for short-circuiting said second relay.

11. In a combined telephone and alarm system, the combination with a normally closed main circuit leading to a central exchange, of a spring-jack and an operators cord-circuit at the central exchange, a plurality of substations and a source of current included in said main circuit, a relay in said main circuit, a local alarm-circuit controlled by said relay, alarm apparatus in said alarm-circuit, means at one of said substations for repeatedly opening said main circuit, whereby said alarm apparatus is actuated, a second relay in said circuit, a local indicating-circuit including the armature of said second relay, said armature being normally attracted by said relay to open said indicating-circuit, recording apparatus and indicating devices included in said indicating-circuit, means at one of said substations for repeatedly including a resistance in the said main circuit, whereby said second relay is weakened to allow closure of said indicating-circuit to repeatedly actuate said recording apparatus and said indicating devices,

a third relay included in said circuit, a local circuit controlled by the said third relay including the armature for said relay, said armature being normally attracted by said third relay to open said local circuit, an additional winding for said second'relay included in said local circuit, denergization of said third relay upon the opening of said main circuit causing the closure of said local circuit controlled by said third relay, whereby said additional winding is energized to prevent closure of said indicating-circuit, telephonic apparatus at oneof said substations, resistance adapted upon the actuation of said telephonic apparatus to be included in said main circuit, whereby said second relay is continuously weakened to allow a continued closure of said indicatingcircuit, whereby said recording apparatus in said indicating-circuit is inactive and the indicating devices in said circuit are continuously actuated, and means upon insertion of a plug in said spring-jack for short-circuiti-ng said second and third relays and for opening said indicating-circuit.

12. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a sensitive relay in said circuit, said relay being responsive to slight changes of current strength in said circuit, and means associated with said relay to prevent its actuation upon a larger change of current strength in'said circuit.

13. In an alarm system, the combination with a normallyclosed main circuit, ofa source of current in said circuit, a sensitive electromagnetic signal-controlling device in said circuit, said electromagnetic device being responsive to slight changes in the strength of current in said circuit, and means for pre-. venting the actuation of the signal associated with said electromagnetic device upon a larger change of current strength in said circuit.

14.v In an alarm system, the combination with a normally closed main circuit, of asource of current in said circuit, a sensitive relay included serially in said circuit and responsive to slight resistance'changes in said circuit, an additional relay in said circuit responsive only to comparatively, great resistance changes in said circuit, andj m'eans associated with saidv sensitive relay foi preventing actuation thereof upon actuation of said additional relay.

15. In an alarm system, the combination. with a normally closed main circuit, ofa source. of current in said circuit, a non-sensitive re-x lay in said circuit responsive only to com-. paratively great resistance change in said circuit, a second relay havinga sensitive winding included in said circuit and responsive to. slight resistance change in said circuit, and an additional winding for said second relay for preventing said relay from becoming inert upon great resistance change in said circuit.

16. In an alarm system, the combination with a normally closed main circuit, of asource.

of current in-said circuit, a non-sensitive relay included serially in said circuit and actuated only upon comparatively great resistance changes in said circuit, asecond relay having a sensitive winding included serially in said main circuit, said winding causing said relay to become i'nert'upon a'very slight increase of resistance insaid circuit, and an additional winding for said sensitive relay for preventing said'relay from becoming inert upon comparatively great resistance increase in said circuit. i

-17. In an-alarm system, the combination with a normally closed main circuit, of asource of current in said circuit, a non-sensitive relay included serially in said circuitand actuated substantially only upon opening of said main circuit, an additional relay having a Winding included serially in said main circuit, and a second Winding for said additional relay for preventing said relay from becoming inertupon opening of the main-line circuit.

18. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a non-sensitive relay included serially in said circuit adapted to be actuated only upon opening of said circuit, a second relay having a windingincluded serially in said main circuit, a third non-sensitive relay connected in bridge of said Winding, an additional winding for said second relay, and a local circuit controlled by said third relay and including said additional'winding, opening of said main circuit causing said third relay to close said local circuit whereby said second relay is prevented from becoming inert.

1.9. In an alarm system, the combination with a normallyclosed main circuit, of asource of current in said circuit, a non-sensitive relay in said circuit actuated only upon substantially open circuit, a second relay having a Winding connected in said circuit, a third relay connected with said circuit, a local circuit controlled by said third relay, an additional winding for said second relay included in said local circuit, opening of said main circuit causing said third relay to close said local circ'uit whereby said second relay is prevented frombecoming inert, and a signaling-circuit controlled by said second relay.

- 20. In an alarm system, the combination with anormally closed main circuit, of a source of current in said circuit, a non-sensitive relay included serially in said circuit and actuated only upon substantially open circuit, a second relay having a winding included serially in said circuit, said winding being sensitive and causing said relay to become inert upon only slight increase of resistance in said circuit, a third relay connected in said main circuit in bridge of said sensitive winding of said second relay, said third relay being also non-sensitive, a normally open local circuit controlled by said third relay, an additional winding for said second relay included in said localcircuit,

' opening of said main circuit causing said nonsens1t1ve relays to become inert whereby said local circuit is closed to prevent said second relay from becoming inert, and a signalingcircuit controlled by said second relay.

21. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a non-sensitive relay included seriallyin said circuit and responsive I only to comparatively great resistance increase in said circuit, alarm mechanism controlled by said relay, a second relay having a winding inveluded serially in said maln circuit, said wlnding being sensitive and causinginertness of said second relay upon only slight increase of 'resistance in said main circuit, a third relay controlled by said third relay, an additional winding for said second relay included in said local circuit, and a signal-circuit controlled by'said second relay, a slight decrease of current in said main circuit causing only said second relay to become inert, whereby said signal-circuit is closed, a comparatively large decrease of current in said main circuit causing saidnon-sensitive relays to become inert whereby the local circuit controlled by said third relay, is closed and whereby said second relay is prevented from becoming inert.

22. In an alarm system, the combination with a central station, of a line leading there-. from and connecting with a plurality of substations, a first and second relay at the cen-.

tral station connected with the line, means at some of the substations for changing the condition. of the line for causing actuation of said first relay, means at some of the substations for changing the condition of the line tending to cause actuation of both of said relays, and means at the central station for preventing actuation of said first relay upon such tendency to actuate both relays whereby only said second relay is actuated.

' 23. In an alarm system, the combination with a normally closed main circuit extending from a central exchange, of a plurality of substations connected therewith, a non-sensitive relay at the central exchange included serially in said circuit, a sensitive relay at said substation included serially in said circuit, means at said substation for varying the resistance of said circuit to cause actuation of only said sensitive relay, means upon actuation of other substation apparatus for causing actuation only of said non-sensitive relay, independent signal-circuits controlled by each relay, telephone apparatus at the substations, and tele-- phone apparatus at the central exchange normally disconnected from the line, connection of said central exchange telephonic apparatus with the line causing a shunt-circuit to be connected about said non-sensitive relay.

24. Ina telephone and alarm system, the

IIO

ratus at the telephone-stations, signals controlled by each relay, telephone apparatus at the central exchange, and normally ineffective means for removing the impedance of the additional relay from said circuit upon conversation therethrough.

25. In a telephone and alarm system, the combination with a normally closed main circuit extending from a central exchange, of alarm and telephone substations connected with said line, a relay at thecentral exchange stations, an additional relay at the central exchange responsive to only actuations of apparatus at the telephone-stations, signals controlled by each relay, telephone apparatus at the central exchange, and normally inefi ective means for shunting. the additional relay from the circuit upon conversation therethrough.-

26. In an alarm and telephone system, the combination with a line extending from a central exchange, of alarm and telephone substations connected with said line, a relay at the central exchange responsive only to apparatus at the telephone-substations,signals controlled by said relay, and telephone apparatus at the central exchange normally disconnected from the line, connection of said central-exchange telephone apparatus with said line causing closure of a normally open short-circuit path about said relay to cause the impedance of said relay to be removed from the talkingcircuit.

27. In acombined alarm and telephone system, the combination with a normally closed main line extending from the central exchange and including telephone and alarm substations, actuation of apparatus at said alarmstations causing said line to be opened, actuation of telephone apparatus at said telephone-stations causing resistance to be included in said circuit, a sensitive relay at the central exchange included serially in said circuit adapted to be actuated only upon actuation of telephone apparatus at the substations, telephone-signals controlled by said sensitive relay, a non-sensitive relay included serially in said line-circuit at the central exchange adapted to be actuated only upon actuation of alarm-substation apparatus, alarm-signals controlled by said non-sensitive relay, telephone apparatus at the central exchange adapted to be inductively connected with said line, and means for removing the impedance of said relays from the main circuit only when conversation is carried on therethrough.

28. In a combined telephone and alarm system, the combination with a normally closed main circuit including alarm and telephone substations and terminating at a central exchange in -a spring-jack, alarm apparatus at said substations for opening said line, telephone apparatus at said telephone-stations for including resistance in said line-circuit, a relay at the central exchange responsive only to actuations of the apparatus at the alarmstations, a sensitive relay actuated only upon inclusion of resistance in the circuit at the telephone-substations, an operators cord-circuit at the central exchange for connecting an operator or another line with said main circuit, and means upon connection of said cord-circuit with said springack for closing.

, a short circuit about the sensitive relay to remove its impedance from the talking-circuit. responsive only to apparatus at said alarm- Item, the combination with a normally closed 29. In a combined alarm and telephone sysmain circuit including alarm and telephone substations and terminating at a central exchange, of telephone apparatus at the central exchange normally disconnected from the main circuit, a source of current in said main circuit, means at the alarm-substations for opening said line, a non-sensitive relay included serially in the circuit at the central exchange and responsive only to actuations of signals from said alarm-substations, means at the telephone-substations for including a re sistance in said main circuit, a second relay at the central exchange having a winding serially included in said main circuit, said winding being sensitive and causing actuation of said relay only upon inclusion of resistance in said line at the telephone-substations, a'

ing inert when said line is open at said alarmstations, and means upon telephonic conversation through said main circuit for removing the impedance of said relays therefrom.

30. In a combined alarm and telephone system, the combination with a normally closed main circuit including alarm and telephone substations and terminating at a central exchange, of telephone apparatus at the central exchange normally disconnected from the main circuit, a source of current in said main circuit, means at the alarm-substations for opening said line, a non-sensitive relay included serially in the circuit at the central exchange and responsive only to actuations ofsignals from said alarm-substations, means at the telephone-substations for including a resistance in said main circuit, a second relay at the central exchange having a winding serially included in said main circuit, said Winding being sensitive and causing actuation of said relay only upon inclusion of resistance insaid line at the telephone-stations, a third relay associated with said second relay for preventing said second relay from becoming inert when said line is open at said alarm-stations,-

a condenser shuntingtlie first relay, and means upon connection of said central-exchange telephone apparatus with said main. circult for closinga short circuit abouts'aid secondand third relays-whereby the impedance'ofsaid:

relays is removed from the talking-circuit."

31. In an alarm system, the combination. with a normally closedmain circuit, of a source of current in said circuit, a non-sensitiveres lay in: said circuit'iadapted to become inert onlyupon comparatively great resistance increase in said circuit, a second relay having a sensitive wind-ing. included in said circuit and: adapted to become inert, upon slight resistance increase in'said circuit, an additional; winding for saidsecondrelay for preventing said relay frombecoming inert upon great re.-- sistance change in. said. circuit, and a third 1e lay controllinga circuit through said additional-winding. :l 1

32.2.In analarm. system, the combination with a normally closed main circuit, .of a source of current in said circuit,a' non-sensitive relay irisaid .circuit adapted to become inert. only upon comparatively great resistance in,- creasei-n said circuit, a second relay having a sensitive winding included in said circuit and' adapted to become inert upon slight resistance increase in said circuit,f an additional windingfor said-second relay for preventing said relay from becoming inert upongreat resistance change in said circuit, and a third relay controlling a:..circuit through said additional winding, said third relay being included serially in circuit with said non-sensitive relay. i

33. In an alarm-system, the combination with a normally closed main circuit, of as'ource of current. in said.v circuit, a non-sensitive relay in .said circuit adapted to become. inert. only upon comparatively great resistance increasein said circuit, a second relay having a sensitive winding included in said circuit and adapted to become inert upon slight resistance increase in saidcircuit, anadditional winding for said second relay for preventing said relay from becoming inert upon great resistance change in said circuit, and a third relay controlling a circuit through said additional winding, said third relay being connected in bridge of the sensitive winding of the second relay.

34. In an alarm system, the combination with a normally closed main circuit, a source of current in said circuit, a nonsensitive relay in said circuit adapted to become inert only upon comparatively, great resistance increase in said circuit, a second relay having a sensitive winding included in said circuit and adapted to become inert upon slight resistance increase in said circuit, an additional winding for said second relay for preventing said relay from becoming inert upon great resistance change in said circuit, and an additional nonsensitive relay included serially in circuit with said othernon sensitive relay and controlling the circuitthro'u'gh said additional winding of thesecondrelayi I .l

35. In an alarm system, the combination. 1 with ano'rmally closedmaincircuit, of a source of current insaid circuit; a non-sensitive relay in said circuit adaptedtoibecomeinert.only upon comparatively great resistance increase. in said: circuit, azsecond relay having a sensitive Winding connected serially infsaid circuit withIsaidrelay, said sensitive winding allow-. .ing said second relay to' become inert upon ,sliglit: resistance increase .in said circuit, an additional winding 'for said second relay for preventing said relay from becoming inert upon great resistance-change in: said circuit, and an additional.non-sensitive relay connected: in bridge ofthe sensitive winding of thesecond relay and co'ntrollinga circuit through the additional winding for said second relay.

36. In an alarm system, the combination. I with a normally closed main circuit, of a source of current in said circuit, a normally inactive sensitive relay in said closed circuit, said relay becoming active upon slight changes of.current strength in said circuit, and means asso-, ciated with said relay .to prevent itsactuation. upon a larger changeof current in said circuit.

37 In an alarm system, the combination. With a normally closed main circuit,- of a source of current in said circuit, a normally inactive. sensitive electromagnetic signal-controlling; device in said circuit, said device becoming active uponslight changes in the strength of.

current in said circuit, and means'for prevent-- ing the'actuation of a signal controlled. bysa id, electromagnetic device upon a larger change. of current strength in said circuit.

' 38. In. an alarm system, the combination with a normally closed main circuit,1of a source of current in said circuit, a sensitive relay in said circuit and normally inactive upon a slight current-flow through the circuit upon closure thereof, and means associated with said relay to prevent its actuation upon an increase oi"v the current-flow in said circuit which would tend to cause actuation of the relay.

39. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a sensitive relay in said closed circuit irresponsive to the normal current-flow through the circuit, said relay being responsive to slight increases of the current strength in said circuit, and means associated with said relay to prevent its actuation upon a larger current-flow in said circuit which wouldtend to cause actuation of said relay.

LO. In an alarm system, the combination with a normally closed main circuit, of asource of current in said circuit, a sensitive relay in said closed circuit irresponsive to the normal current-flow through the circuit, said relay being responsive to slight increases of the current strength in said circuit, means associated with said relay to prevent its actuation upon a larger current-flow in said circuit which would tend to cause actuation of said'relay, and an additional relay in said circuit for controlling said means.

41. In an alarm system, the combination with a normally closed main circuit,of a source of current in said circuit, a sensitive relay in said closed circuit irresponsive to the normal current-flow through the circuit, said relay being responsive to slight increases of the current strength in said circuit, means associated with said relay to prevent its actuation upon a larger current-flow in said circuit which would tend to cause actuation of said relay, and a non-sensitive relay included in said circuit and responsive to only large current changes for controlling said means.

42. In an alarm system, the combination with anormally closed main circuit,ofa source of current in said circuit, a sensitive relay in said closed circuit irresponsive to thenormal current-flow therethrough but responsive to slight current increase in the circuit, and a non-sensitive relay included in said circuit and responsive only' to comparatively large current-flow through said circuit, said nonsensitive relay preventing actuation of said sensitive relay upon large currentflow through. the circuit.

43. In an alarm-circuit, the combination with a normally closed circuit, of a source of current in said circuit, a sensitive relay included serially in said circuit and adapted to become inert upon slight resistance increase in said circuit, an additional relay in said circuit responsive only'upon comparatively great resistance increase in said circuit, and means associated with said sensitive relay for preventing inertness thereof upon actuation of said additional relay.

44. In an alarm system, the combination with a normally closed main circuit, of a source of current in said circuit, a non-sensitive relay in said circuit adapted to become inert only upon comparatively great resistance increase in said circuit, a second relay having a sensitive winding included in said circuit and adapted to become inert upon slight resistance increase in said circuit, and an additional winding for said second relay'for preventing said relay from becoming inert upon great resistance change in said circuit.

45. In a telephone and alarm system, the

relays to remove their impedance from the telephone-circuit.

46. In a combined telephone and? alarm system, the combination with a normally closed main circuit extending from a central exchange, of alarm and telephone substations connected with said line, a relay at the central exchange responsive only to apparatus at said alarm-stations, an additional relay at the central exchange responsive to only actuations of apparatus at" the telephone-stations, signals controlled by each relay, telephone apparatus at the central exchange, and means mechanically actuated upon connection of the telephone apparatus at the central exchange with the line for closing a normally open short circuit about the additional relay to remove its impedance from the talking-circuit.

In witness whereofl hereunto subscribe my name this 11th day of December, A. D. 1903.

eARRIsoN BABCOOK.

Witnesses:

CHARLES J SCHMIDT, LEONARD W. NOVANDER.

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