Patent ID: 9714537
Date: 2017-07-25
CPC Classifications: E06B,G09F

Claim:
1. A door communication device for use with a door having an inside surface and an outside surface, the door communication device comprising: an interior unit adapted to be located adjacent the inside surface of the door, the interior unit having a first viewing aperture; an exterior unit adapted to be located adjacent the exterior surface of the door, the exterior unit having a second viewing aperture adapted to be in optical communication with the first viewing aperture of the interior unit along an optical viewing pathway between the first viewing aperture and the second viewing aperture; and a first shaft having a first end, a second end and a hollow bore extending from the first end to the second end of the first shaft, the first shaft adapted to be at least partially located within the door such that the optical viewing pathway between the first viewing aperture and the second viewing aperture extends through the bore of the first shaft, the first shaft comprising an intumescent material; whereby when the first shaft is heated above a predetermined temperature the intumescent material of the first shaft expands to block the bore of the first shaft and thereby seal the first end of the first shaft from the second end of the first shaft, and wherein the interior unit includes a rotatable interior message wheel having an interior message plate, the first end of the first shaft being coupled to the interior message plate, the first shaft and the interior message plate being selectively rotatable about a central axis.