US1225935A - Fire-alarm telephone transmitting mechanism. - Google Patents

Fire-alarm telephone transmitting mechanism. Download PDF

Info

Publication number
US1225935A
US1225935A US82094814A US1914820948A US1225935A US 1225935 A US1225935 A US 1225935A US 82094814 A US82094814 A US 82094814A US 1914820948 A US1914820948 A US 1914820948A US 1225935 A US1225935 A US 1225935A
Authority
US
United States
Prior art keywords
circuit
contacts
alarm
telephone
trouble
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US82094814A
Inventor
David G Dee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ROCHESTER H ROGERS
Original Assignee
ROCHESTER H ROGERS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ROCHESTER H ROGERS filed Critical ROCHESTER H ROGERS
Priority to US82094814A priority Critical patent/US1225935A/en
Application granted granted Critical
Publication of US1225935A publication Critical patent/US1225935A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M11/00Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/04Telephonic communication systems specially adapted for combination with other electrical systems with alarm systems, e.g. fire, police or burglar alarm systems

Definitions

  • My present invention has for its object to provide certain improvements in alarm signaling mechanism and circuits controlled by it by means of which fire alarm signals may be despatched over the lines of telephone exchanges from the subscribers station, whereby, upon the completion of the operation of the call box or sending apparatus, the subscribers telephone circuit is restored to its normal condition in readiness' to initiate a call or respond to calls despatched from the central ofiice or exchange.
  • the object of the invention in other terms it may be said that it consists in providing the signaling mechanism with trip devices which control the alarm circuit that it is rendered capable of despatching signals automatically after said apparatus has been started into operation and which will restore the telephonecircuit to its normal condition after it has completed its last round of signals.
  • My invention also has for its further object to provide a trouble alarm mechanism which is normally inoperative and is arranged to maintain the alarm circuit under constant' test to the end that a break in the circuit,
  • Figure 1 is a diagrammatic view 'illustrating mechanism embodying my present in e t n, oget er with a simp e a r ngement-of circuits by means of which the operation of the various parts will be more easily understood, and
  • Fig. 2 is an enlarged detail View of the alarm mechanism.
  • Apparatus embodying my invention is intended to be used in conjunction with established telephone exchange systems, the fire alarm signaling or calling instruments used in conjunction therewith being adapted, when actuated, to transmit impulses of current indicating the code signal of the instrument.
  • the telephone subscribers instrument circuit is shown-comprising the wires A and B leading from thespring contacts of the central oiiice switchboard jack J, said subscribers circuit comprising the 'usual telephone set consisting of the transmitter T and receiver R.
  • the central office apparatus is shown diagrammatically as comprising the answering and calling cord circuits. indicated by 1 and 2, respectively, supplied with current from a battery3 and 'in circuit wlth which is the operators set comprising the receiver 4 and the transmitter 5.
  • the fire alarm circuit leading to fire department headquarters may comprise the line wires 8, s leading from a special plug S and carrying current'from the battery 8 through magnets 8 the latter may, in turn, control an armature s in a local circuit supplying current from a battery 8 to the operating magnets of a recording device or punch s.
  • the fire alarm box mechanism comprises an arbor C which may be driven by a spring actuated gear train of any desired construction for imparting a uniform speed of rotation thereto and adapted to rotate the arbor and the code wheel mounted thereon a plurality of revolutions for the purpose of repeating the given code signal a number of times in succession.
  • the clock train operating the arbor C comprises a notched wheel with which an escapement pallet cooperates which is normally restrained against movement, locklng the clocl; train,
  • an arm 0 attached thereto which engages a restraining device such as an armature c which may be disengaged by the operation of a release magnet 0 whichis energized when its operating circuit is closed, as will be further described.
  • a restraining device such as an armature c which may be disengaged by the operation of a release magnet 0 whichis energized when its operating circuit is closed, as will be further described.
  • the signal box mechanism comprises various contacts and devices for operating them which are controlled by switch operating cams and a code wheel a mounted on the arbor C.
  • the latter also carries an arm provided with a finger which extends outwardly, as indicated at 0 cooperating with a trip lever E and a spur gear Wheel F to first lift the trip and then advance the gear wheel the distance of one tooth for each complete rotation of the arbor C.
  • the gear wheel F is journaled upon a stud f and connected thereto are two cam members F F controlling the operation of the levers F 3 and F which are journaled upon a common pivot and control the opening and closing of two different sets of contacts, by means of which the subscribefls circuit is first rendered in condition to despatch a signal, at whichtime the subscribers telephone set is cut out, and which restores said circuit to its normal condition after the alarm mechanism has completed its last round.
  • a trouble alarm or trouble indicating mechanism on the subscribers circuit is also set into action, by the release of the. armature r of relay R.
  • cam wheels F and Fit are provided respectively with the projections f and P, which in their normal position cooperate with the levers -F and F to hold them in the position shown in Fig. 1.
  • the projection f is of a length approximately twice that of the projection f and the former is located relatively to the latter so that as the alarm mechanism reaches the limit of its movement and stops, after the last-round of signals has been despatched, said projection P will contact with and operate its lever F causing the contacts controlled thereby to be restored to their normal position while the contacts controlled by the lever F remain in their actuated position.
  • the signal box mechanism further comprises a pair of spring contacts 9, g which are normally held in contact by an insulated pin f on the lever F and which open of their own accord when the lever is released by its cam projection f and when open, cuts out the local trouble alarm and renders it inoperative until the box mechanism has been restored manually by the inspector. However, by reason of the length of the cam projection f the telephone line is restored to its normal condition of service as soon as the box mechanism has finished its work.
  • the subscribers telephone instrument circuit is illustrated as comprising the wires A and B, and the former leads directly to the contact spring 71., the circuit being continued from the spring 72. to the central ofiice over the conductor A which terminates in one of the springs of the switchboard jack.
  • the other wire B leads to the contact spring 71 and has attached to it the conductor B which completes the subscribers circuit to the central ofiice.
  • an armature b which is normally closed against the contact 6, but which may be withdrawn therefrom by current. flowing in the coils of the relay R arranged in a circuit composed of the Wire 1', connected to line wire B and the wires 1", 1' leading to the spring 9.
  • the spring 9 is connected to spring h by the tie T
  • the wires 1", r are normally disconnected but the circuit may be completed through them by an armature r and contact 1".
  • the release magnet 0 is employed having a local circuit of any desired length composed of the wires 0 and a supplied with current from the battery X and leading to the terminals of the windings of the coils of the relay R.
  • a trouble alarm mecha- 7O nism comprlsing a c1rcu1t having a palr of contacts and an alarm apparatus controlling the first mentioned contacts and serving to despatch current impulses over the line circuit and simultaneously operating the trouble circuit contacts to break the trouble circuit.
  • a trouble alarm mecha nism comprising a circuit having a pair of normally closed contacts and an alarm apparatus serving-to open the latter and control the line circuit contacts to despatch impulses of current over said line circuit.
  • a trouble alarm mechanism comprising a circuit having a pair of normally closed contacts and an alarm mechanism adapted to transmit a plurality of groups of impulses controlling the line circuit'contacts to disconnect the telephone set during the transmission of the impulses and subsequently reconnect it to the line upon the termination'of the last group of impulses, said mechanism also serving to open the trouble circuit contacts upon the commencement of the transmission of the alarm impulses and permitting them to remain open after the telephone set has been reconnected to the line.
  • a telephone fire alarm system the combination with a subscribers line circuit provided with a telephone set having a plurality of sets of contacts, one set constituting a pair of normally closed contacts and a pair of normally open contacts through which latter the telephone line may be closed independently of the telephone set, and the remaining set constituting a pair of normally closed contacts, of an impulse despatching mechanism adapted to reverse the condition of the first set of contacts and open the second set of contacts, subsequently producing variations in the potential flow of current in the line, and finally restoring the normally closed contacts of the first set to their normal condition, leaving the sec- 6nd set of contacts open.
  • a combination with a subscribers line circuit provided with a telephone set and having two sets of contacts, the first set eonstituting'a pair of normally closed contacts and a pair of normally open contacts through which latter the telephone line may be closed independently of the telephone set, the other set constituting a pair of normally closed contacts, a trouble alarm circuit cooperating with the second set of'contacts, of an impulse despatching mechanism adapted to reverse the condition of the first set of contacts and open the second set of contacts, and to subsequently produce Variations in the potential flow of current in the line and finally restore the first set of contacts to their normal condition leaving the second set of contacts open.
  • a telephone fire alarm system the combination with a subscribers line circuit, of a trouble circuit cooperating with said line circuit, a pair of normally open contacts in said line circuit, a pair of normally closed contacts in said trouble circuit, and an impulse despatching mechanism including means for cooperation with the contacts aforesaid whereby the contacts in the sub scribers circuit may be opened and closed during one operation of the alarm despatching mechanism, and those in the trouble circuit may be simultaneously opened and maintained in such position after the commaining outer contact, and simultaneously opens the contacts in the trouble circuit aforesaid.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Alarm Systems (AREA)
  • Fire Alarms (AREA)

Description

D. G. DEE.
FIRE ALARM TELEPHONE TRANSMITTING MECHANISM.
APPLICATION FILED FEB. 25. 19M.
Patented May 15, 1917.
l J wi/limaooao rr s raws M nna or.
DAVID G. DEE, OF ROCHESTER, NEW YOR ROCHESTER H. ROGERS, 'O
K, ASSIGNOR, BY MESNE ASSIGNMENTS, TO F ROCHESTER, NEW YORK.
FIRE-ALARM TELEPHONE TRANSMITTING -MECHANISM.
Specification of Letters Patent.
Application filed. February 25, 1914. Serial No. 820,948.
To all whom it may concern:
Be it known that I, DAVID G. DEE, of
Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Fire- Alarm Telephone Transmitting Mecha nisms; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the referencenumerals marked thereon.
My present invention has for its object to provide certain improvements in alarm signaling mechanism and circuits controlled by it by means of which fire alarm signals may be despatched over the lines of telephone exchanges from the subscribers station, whereby, upon the completion of the operation of the call box or sending apparatus, the subscribers telephone circuit is restored to its normal condition in readiness' to initiate a call or respond to calls despatched from the central ofiice or exchange.
To state the object of the invention in other terms it may be said that it consists in providing the signaling mechanism with trip devices which control the alarm circuit that it is rendered capable of despatching signals automatically after said apparatus has been started into operation and which will restore the telephonecircuit to its normal condition after it has completed its last round of signals. My invention also has for its further object to provide a trouble alarm mechanism which is normally inoperative and is arranged to maintain the alarm circuit under constant' test to the end that a break in the circuit,
or a grounding of the conductors will automatically set up a disturbance of said trouble mechanism. This trouble circuit I also arrange so that it will be rendered inoperative when the alarm mechanism is in operation. To these and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of'the specification.
In the drawings:
Figure 1 is a diagrammatic view 'illustrating mechanism embodying my present in e t n, oget er with a simp e a r ngement-of circuits by means of which the operation of the various parts will be more easily understood, and
Fig. 2 is an enlarged detail View of the alarm mechanism.
Similar reference numerals throughout the several figures indicate the same parts.
Apparatus embodying my invention is intended to be used in conjunction with established telephone exchange systems, the fire alarm signaling or calling instruments used in conjunction therewith being adapted, when actuated, to transmit impulses of current indicating the code signal of the instrument. In illustrating the present invention the telephone subscribers instrument circuit is shown-comprising the wires A and B leading from thespring contacts of the central oiiice switchboard jack J, said subscribers circuit comprising the 'usual telephone set consisting of the transmitter T and receiver R. The central office apparatus is shown diagrammatically as comprising the answering and calling cord circuits. indicated by 1 and 2, respectively, supplied with current from a battery3 and 'in circuit wlth which is the operators set comprising the receiver 4 and the transmitter 5. Associated with the line jack'J are the contacts of the customary circuit of the pilot lamp j by means of which the operator is signaled when the subscribers circuit is closed. The fire alarm circuit leading to fire department headquarters may comprise the line wires 8, s leading from a special plug S and carrying current'from the battery 8 through magnets 8 the latter may, in turn, control an armature s in a local circuit supplying current from a battery 8 to the operating magnets of a recording device or punch s.
The fire alarm box mechanism comprises an arbor C which may be driven by a spring actuated gear train of any desired construction for imparting a uniform speed of rotation thereto and adapted to rotate the arbor and the code wheel mounted thereon a plurality of revolutions for the purpose of repeating the given code signal a number of times in succession. The clock train operating the arbor C comprises a notched wheel with which an escapement pallet cooperates which is normally restrained against movement, locklng the clocl; train,
Patented May 15, 19117..
by an arm 0 attached thereto which engages a restraining device such as an armature c which may be disengaged by the operation of a release magnet 0 whichis energized when its operating circuit is closed, as will be further described.
The signal box mechanism comprises various contacts and devices for operating them which are controlled by switch operating cams and a code wheel a mounted on the arbor C. The latter also carries an arm provided with a finger which extends outwardly, as indicated at 0 cooperating with a trip lever E and a spur gear Wheel F to first lift the trip and then advance the gear wheel the distance of one tooth for each complete rotation of the arbor C. The gear wheel F is journaled upon a stud f and connected thereto are two cam members F F controlling the operation of the levers F 3 and F which are journaled upon a common pivot and control the opening and closing of two different sets of contacts, by means of which the subscribefls circuit is first rendered in condition to despatch a signal, at whichtime the subscribers telephone set is cut out, and which restores said circuit to its normal condition after the alarm mechanism has completed its last round. At the time the fire alarm circuit is completed and the alarm box is set into operation, a trouble alarm or trouble indicating mechanism on the subscribers circuit is also set into action, by the release of the. armature r of relay R.
Referring now to the construction of the cam wheels F and Fit will be observed that they are provided respectively with the projections f and P, which in their normal position cooperate with the levers -F and F to hold them in the position shown in Fig. 1. The projection f is of a length approximately twice that of the projection f and the former is located relatively to the latter so that as the alarm mechanism reaches the limit of its movement and stops, after the last-round of signals has been despatched, said projection P will contact with and operate its lever F causing the contacts controlled thereby to be restored to their normal position while the contacts controlled by the lever F remain in their actuated position.
The signal box mechanism further comprises a pair of spring contacts 9, g which are normally held in contact by an insulated pin f on the lever F and which open of their own accord when the lever is released by its cam projection f and when open, cuts out the local trouble alarm and renders it inoperative until the box mechanism has been restored manually by the inspector. However, by reason of the length of the cam projection f the telephone line is restored to its normal condition of service as soon as the box mechanism has finished its work. There are also a set of three contacts h, k and h, the first of which is held in contact with the second by an insulated pin f on the lever F 4 and through which the subscribers telephone circuit leads under normal conditions and by means of which this circuit is interrupted. During the operation of the box the spring it moves into the dotted line position in contact with the spring k and as the latter is provided with a lateral extension k which cooperates with the teeth of the code wheel 0, said spring is moved into and out of contact with the spring it to despatch the code signal of the alarm box during the rotation of the code wheel 0 The subscribers telephone instrument circuit is illustrated as comprising the wires A and B, and the former leads directly to the contact spring 71., the circuit being continued from the spring 72. to the central ofiice over the conductor A which terminates in one of the springs of the switchboard jack. The other wire B leads to the contact spring 71 and has attached to it the conductor B which completes the subscribers circuit to the central ofiice. In the conductor B there is inserted an armature b which is normally closed against the contact 6, but which may be withdrawn therefrom by current. flowing in the coils of the relay R arranged in a circuit composed of the Wire 1', connected to line wire B and the wires 1", 1' leading to the spring 9. The spring 9 is connected to spring h by the tie T The wires 1", r are normally disconnected but the circuit may be completed through them by an armature r and contact 1". r is normally held in retracted position by the relay R which is included in the circuit of the release magnet 0 One of the alarm box mechanisms, previously described, will suflice for a single building and a single telephone circuit, but in order that it may be set into operation from any one of a plurality of different places throughout the building, either automatically, by the useof thermostats, or manually by means of push buttons, the release magnet 0 is employed having a local circuit of any desired length composed of the wires 0 and a supplied with current from the battery X and leading to the terminals of the windings of the coils of the relay R. This circuit is closed and for this reason the relay R is given a high resistance of approximately 200 ohms and the magnet c is of approximately 3' ohmsresistance. The thermostatic devices 0 or the push button 0 when closed, short circuits the relay R permitting the full strength of the current from the battery X to energize the release magnet c whereupon the re-' This armature straining member or armature 0' is attracted and the mechanism .of the fire alarm box permitted to begin its cycle of operation. The deenergizing of the rela R releases the armature r whereupon tli e relay R is energized. 'Ihe armature b of the last mentioned relay is connected by the tap b to the wire 7", and when it is attracted it engages a contact b connected by the lead I) to the wire 1"; consequently when the armature is in attracted position it short circuits the relay magnets so that it is successively pulled up and released until the circuit 1", r, r is open at the contacts 9, g by the movement of the lever F These contacts, as before mentioned, cut out the buzzer, or trouble alarm, during the operation of the signal box mechanism, but as these are closed under normal conditions the trouble indicating mechanism is always in condition to be operated in the event the actuating alarm circuit 0 c is opened at any point.
Describing the movements of the box and the .various parts thereof and the circuits by which the present invention is carried out, it will be assumed in the first instance that normal conditions exist on the subscribers instrument circuit; that is, the line wires A and B are continuous through to the central oflice, the circuit being open at the usual receiver hook contacts of the subscribers telephone set, the armature b of relay R resting in engagement with the contact I). In the fire alarm box the contacts are all in the normal position shown inthe full lines in Fig. 1,,the pairs of springs g, g being closed together and the springs h, h being in contact; the circuit 0, c of the release magnet c is also complete, being closed through the battery X and the relay R. The operation of the release magnet c in the closed circuit, just described, is prevented by the high resistance of the relay R which is maintained continuously in an energized condition so that the operating circuit of the release magnet is always under test and any failure of the current in the circuit isindicated at once by reason of the release of the armature T which, in falling back against the contact 1' completes the circuit of the trouble relay R bridging it across the telephone linev When the trouble call or indicator is set into operation through the breaking of the circuit of the release magnet 0 it will continue to operate until the circuit is restored. lVhen an alarm signal is despatched, the trouble indicator is thrown into operation fora brief period, but is checked automatically by the nism as soon as the contacts 9, g are separated.
I claim as my invention:
1. In atelephone fire alarm system, the
combination with a subscribers line circuit having a telephone instrument set and proalarm mechavided with contacts normally maintaining said instrument connected to the line and which may be operated to disconnect it and close the line circuit independently of the instrument, of a trouble alarm mecha- 7O nism comprlsing a c1rcu1t having a palr of contacts and an alarm apparatus controlling the first mentioned contacts and serving to despatch current impulses over the line circuit and simultaneously operating the trouble circuit contacts to break the trouble circuit.
2. In a telephone fire alarm system, the combination with a subscribers line circuit having a telephone instrument set and provided with contacts normally maintaining said instrument connected to the line and which may be operated to disconnect it and close the line circuit independently of the instrument, of a trouble alarm mecha nism comprising a circuit having a pair of normally closed contacts and an alarm apparatus serving-to open the latter and control the line circuit contacts to despatch impulses of current over said line circuit.
In a telephone fire alarm system, the combination with a subscribers line circuit having a telephone instrument set and provided with contacts normally maintaining said instrument connected to the line and which may be operated to disconnect it and close the line circuit independently of the instrument, of a trouble alarm mechanism comprising a circuit having a pair of normally closed contacts and an alarm mechanism adapted to transmit a plurality of groups of impulses controlling the line circuit'contacts to disconnect the telephone set during the transmission of the impulses and subsequently reconnect it to the line upon the termination'of the last group of impulses, said mechanism also serving to open the trouble circuit contacts upon the commencement of the transmission of the alarm impulses and permitting them to remain open after the telephone set has been reconnected to the line.
4. In a telephone fire alarm system, the combination with a subscribers line circuit, of an alarm mechanism for despatching current impulses over said line circuit, a local circuit for setting said alarm mechanism in operation, a trouble circuit for maintaining the local circuit under constant test, and trouble circuit contacts under the control of the alarm mechanism for opening said trouble circuit.
5. In a fire alarm telephone system, the combination with a subscribers line circuit, of an'alarm mechanism for despatching current impulses over said line circuit, a local circuit for setting said alarm mechanism in the alarm mechanism is actuated.
6. In a telephone fire alarm system, the combination with a subscribers line circuit provided with a telephone set having a plurality of sets of contacts, one set constituting a pair of normally closed contacts and a pair of normally open contacts through which latter the telephone line may be closed independently of the telephone set, and the remaining set constituting a pair of normally closed contacts, of an impulse despatching mechanism adapted to reverse the condition of the first set of contacts and open the second set of contacts, subsequently producing variations in the potential flow of current in the line, and finally restoring the normally closed contacts of the first set to their normal condition, leaving the sec- 6nd set of contacts open.
7. In a telephone fire alarm system, a combination with a subscribers line circuit provided with a telephone set and having two sets of contacts, the first set eonstituting'a pair of normally closed contacts and a pair of normally open contacts through which latter the telephone line may be closed independently of the telephone set, the other set constituting a pair of normally closed contacts, a trouble alarm circuit cooperating with the second set of'contacts, of an impulse despatching mechanism adapted to reverse the condition of the first set of contacts and open the second set of contacts, and to subsequently produce Variations in the potential flow of current in the line and finally restore the first set of contacts to their normal condition leaving the second set of contacts open.
8. In a telephone fire alarm system, the combination with a subscribers line circuit, of a trouble circuit cooperating with said line circuit, a pair of normally open contacts in said line circuit, a pair of normally closed contacts in said trouble circuit, and an impulse despatching mechanism including means for cooperation with the contacts aforesaid whereby the contacts in the sub scribers circuit may be opened and closed during one operation of the alarm despatching mechanism, and those in the trouble circuit may be simultaneously opened and maintained in such position after the commaining outer contact, and simultaneously opens the contacts in the trouble circuit aforesaid.
10. In a telephone fire alarm system, the
combination with a subscribers line circuit including two contacts with a central 'contact therebetween, said central contact adapted to normally rest against one of said outer contacts, of a trouble circuit cooperating with said line circuit, a pair of normally closed contacts in said trouble. circuit, and an impulse despatching mechanism cooperating with said contacts whereby the operation thereof moves the central contact of the line circuit to rest against the remaining outer contact, and returns said central contact to its normal position at the completion of the operation of the impulse despatching mechanism, said impulse despatching mechanism simultaneously opening the contacts in the trouble circuit at the beginning of its operation and maintaining them in such position.
11. In a telephone fire alarm system, the
.combination with a subscribers line circuit,
of a trouble circuit cooperating with said line circuit, a pair of normally open contacts in said line circuit, a pair of normally closed contacts in said trouble circuit, and an impulse despatching mechanism including disks for cooperation with the contacts aforesaid, the disk cooperating with the contacts of the trouble circuit being provided with a short tooth, and the disk cooperating with the contacts of the line circuit being provided with a relatively longer tooth.
DAVID G. DEE. Witnesses: HYMAN L. WEISS, B. B. Curran.
US82094814A 1914-02-25 1914-02-25 Fire-alarm telephone transmitting mechanism. Expired - Lifetime US1225935A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US82094814A US1225935A (en) 1914-02-25 1914-02-25 Fire-alarm telephone transmitting mechanism.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US82094814A US1225935A (en) 1914-02-25 1914-02-25 Fire-alarm telephone transmitting mechanism.

Publications (1)

Publication Number Publication Date
US1225935A true US1225935A (en) 1917-05-15

Family

ID=3293784

Family Applications (1)

Application Number Title Priority Date Filing Date
US82094814A Expired - Lifetime US1225935A (en) 1914-02-25 1914-02-25 Fire-alarm telephone transmitting mechanism.

Country Status (1)

Country Link
US (1) US1225935A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2512981A (en) * 1944-04-20 1950-06-27 Svoekhotoff Alexander Apparatus for automatically calling police help

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2512981A (en) * 1944-04-20 1950-06-27 Svoekhotoff Alexander Apparatus for automatically calling police help

Similar Documents

Publication Publication Date Title
US1225935A (en) Fire-alarm telephone transmitting mechanism.
US1089404A (en) Fire-alarm signal-box for automatic telephone systems.
US1375059A (en) Signal system
US757030A (en) Signaling apparatus.
US990434A (en) Electrical system for the supervision of watchmen.
US313720A (en) Half to john t
US1294928A (en) Train-despatching system.
US424726A (en) Electric indicator
US1140378A (en) Selective signaling system.
US1029577A (en) Telephone-exchange system.
US2104998A (en) Impulse sender
US1356626A (en) Selective signaling system
US508215A (en) Electric time signaling system
US1306074A (en) Signaling system
US483768A (en) Police-telegraph system
US399505A (en) Transmitting-instrument for electric signaling apparatus
US667434A (en) Signaling system.
US481247A (en) smith
US1233037A (en) Fire-alarm system for telephone-exchanges using line-distributers.
US935049A (en) Calling device for telephone-exchanges.
US785103A (en) Telephone selecting mechanism.
US365726A (en) Electric circuit-testing apparatus
US414879A (en) And charles a
US1061285A (en) Selective system of telephony.
US375543A (en) Electric-circuit changing and signaling apparatus