Alarm device for continually indicating the state of air pressure in a plurality of tires
Patent 3938077 Issued on February 10, 1976. Estimated Expiration Date: 
February 10, 1993. 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 10, 1993. 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 References3806869 InventorsAssigneeApplicationNo. 527010 filed on 11/25/1974US Classes:340/447, Radio wave200/61.25, Fluid pressure actuated340/524, Condition position indicator340/539.1, Radio340/626, Pressure340/870.09, With alarm or annunciator (concurrent with TM)340/870.31, Inductive transmitter455/227Responsive to an input signal of particular predetermined frequencyExaminersPrimary: Waring, Alvin H.Attorney, Agent or FirmForeign Application Priority Data1973-11-28 JAAbstractAn alarm device for informing reduction of pneumatic pressure of tires comprises a group of oscillators each consisting of an oscillator circuit, an electric power supply source thereof, a switch for closing an electric power supply circuit when the internal pressure of the tire is lowered to less than a prescribed value and radiation antenna, a group of receiver tuning circuits having a receiver antenna, a sweep generator, a comparison circuit for generating the gate control signal, a gate circuit for sequentially gating the output of a ratio detection circuit, pulse noise elimination circuits consisting of monostable circuits and smoothing filters, comparators for comparing the smoothed DC signal with reference signals which discriminate the operation of an oscillator, and alarm devices for generating alarm information. | |
