Through-door viewing device
Patent 4869021 Issued on September 26, 1989. Estimated Expiration Date: 
February 1, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 1, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2489060 2491758 2638810 Security viewing device Optical remote-control device for a residence door Patent #: 4561116 InventorApplicationNo. 07/305918 filed on 02/01/1989US Classes:49/171, Viewing, ventilating, or packet passage359/399, Telescope359/894OPTICAL APERTURE OR TUBE, OR TRANSPARENT CLOSUREExaminersPrimary: Kannan, Philip C.International ClassesE06B 7/00 (20060101)E06B 7/30 (20060101) AbstractAn improved through-door viewing device comprising a generally rectangular telescope, a lens mounted in one end of said telescope, an eyepiece mounted in the opposite end of said telescope, a window formed in one side of said telescope adjacent said one end, an escutcheon mounting said telescope in a door for sliding and rotating motion within said escutcheon, a mirror mounted within said telescope and pivotable between a first retracted position lying substantially parallel to the wall of said telescope out of the line of vision through said telescope and a second extended position lying across said line of vision in position to direct vision from said eyepiece through said window of said telescope, flange means responsive to inward sliding of said telescope to move said mirror to said retracted position, and spring means responsive to sliding of said telescope outwardly to urge said mirror to said extended position. | |
