How to Install Electric Bells, Annunciators, and Alarms. / Including Batteries, Wires and Wiring, Circuits, Pushes, Bells, Burglar Alarms, High and Low Water Alarms, Fire Alarms, Thermostats, Annunciators, and the Location and Remedying of Troubles

by Norman H. Schneider

Combination Circuits.

Circuits intended primarily for electric bells or annunciators in houses and apartments may often be also made to serve for other electrical devices such as door openers, house telephones, etc. This subsidiary apparatus may be installed with a little additional wiring or perhaps will not need any other wires, as when both the devices are not used at once.

Fig. 66

Electrical door openers are great conveniences and are practically indispensable where the outside door is on another level to the location of the dweller or where two or more families occupy the same house. The device is simple, consisting of an electrically released spring-plate against which the lock bolt is normally held and a door opening spring.

When the door opener button is pressed, the spring plate is released, releasing the lock bolt by the same action. The door spring then forces the door open enough to clear the opener plate, which flies back into position when the button is released.

These door openers are made in several forms for door frames, such as those on thin doors, iron gates, for surface or rim locks, for thick doors, sliding doors and any other regular type of door.

The push button is the same as used for electric bells and may be located wherever desired. The pushes are wired in multiple as shown in Figs. 66 and 67, which are two circuits of a type of the Western Electric interphone, a system of house telephones supplied for houses and buildings of every size. [Fig. 66] shows a circuit which provides telephone service between the vestibule and the apartments, the door opener wiring being clearly indicated. In [Fig. 67] the circuit provides a more extensive service, enabling the janitor, the apartments and the tradesmen to intercommunicate in the most desirable system. The door opener wiring is also clearly shown.

Fig. 67

The convenience of having telephone connection in the house or hotel and its advantages over speaking tubes are too well known to need extended comment. Where electric bells have already been installed it is quite feasible now to use the same wires for telephones also.

Telephone sets especially designed for this service are manufactured by the Western Electric Company in their interphone series. They are simple and compact, and may be installed by anyone who can put up an electric bell.