Talking door sentinel

Details Talking door sentinel Talking door sentinel

1974-05-06

1976-02-10

Caldwell, John W.

Communications: electrical

Systems

Call station

340221, 179 5P, 200616, G08B 1308, H04M 1104

Patent

active

039381200

ABSTRACT:
A talking door sentinel has a housing which is secured to the edge of a door by means of a bracket. The movement of the door away from the door frame upon its being opened, moves a trigger which actuates a battery-operated voice box inside the housing. The voice box then plays one of a number of pre-recorded messages. When the door is subsequently closed, the approaching door frame resets the trigger so that the sentinel will emit another message when the door is next opened.

REFERENCES:
patent: 2474757 (1949-06-01), Parilla
patent: 3266029 (1966-08-01), Callahan
patent: 3378830 (1968-04-01), Patrick
patent: 3634846 (1972-11-01), Fogiel
patent: 3755802 (1973-08-01), Bobrowski
patent: 3798627 (1974-03-01), Kaufman
patent: 3798833 (1974-03-01), Campbell

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