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US 4,130,728 AGranted
Combined mounting for through-the-wall viewer and intercom
OwnerStephen L. Grauelinventor
Life of this patent
Estimating the term…
Abstract
Seeing and talking through a wall or closed door is conveniently provided by the combination of a one-way observation telescope projecting through the door and a pair of intercom units, one on each side of the door. Each intercom housing has a flange with a hole such that the units may be supported cooperatively by the telescope ends. Each housing may also have protruding tips against the door surface to prevent rotation of the housing.
Claims3
An improved through the wall audio visual communication apparatus for a door, or the like, having a one-way viewing tube extending therethrough, the improvement comprising:
- a pair of hollow housings containing a two-way communication circuit including a pair of microphone/speakers;
- a circuit control switch in one of the housings;
- each housing having a back wall for flatly contacting opposing vertical wall surfaces of said door and each having a centrally apertured flange projecting beyond one end of the housing in the plane of the respective back wall for receiving respective end portions of said one-way tube and securing said housings to said door,
- each said housing having an opening in its wall opposite said back wall for the passage of audio waves to and from the microphone/speakers;
- and,
- a circuit control switch arm rotatably mounted on said one housing connected with the circuit control switch.
3 more elements
Dependencies are inferred from the claim text.