Electronic level
Patent 4654977 Issued on April 7, 1987. Estimated Expiration Date: 
November 19, 2005. 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.
November 19, 2005. 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 3786472 Electrically actuated level Device for setting and retaining a fixed direction Level indicating device Illuminated level Patent #: 4506450 InventorAssigneeApplicationNo. 06/799406 filed on 11/19/1985US Classes:33/366.12, Plural nonparallel axes or plural orientation sensors33/366.21, Having resistive or contact circuit control element33/379BubbleExaminersPrimary: Little, WillisAttorney, Agent or FirmInternational ClassesG01C 9/00 (20060101)G01C 9/06 (20060101) AbstractAn electronic level having a horizontal and/or a vertical transducer, each of which exhibits an effective impedance that is a function of the deviation of that transducer from a reference plane. Preferably, each transducer is an electrolytic transducer formed of a container partially filled with electrolytic liquid. Depending upon the general horizontal or vertical orientation of the level, one or the other transducer is connected to a drive signal generating circuit which supplies an output drive signal of a magnitude that is a function of the impedance of that transducer. This output drive signal is applied to a display driver which, in turn, drives an array of visual indicators in accordance with the output signal magnitude. | |
