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US 4,539,547 AGranted
Low liquid level sensing and warning circuit
AssigneeFord Motor Company
InventorsGeorge Nagy, Jr., Clement W. Rowan
Life of this patent
Estimating the term…
Abstract
A circuit for sampling the conditions of a liquid level sensor for a short period of time after the circuit is turned on and energizing a warning indicator for an initial check-out period that is followed by continuous energization in the event the sensor indicates a low liquid level condition during the sampling period.
Claims4
A circuit connected to a liquid level sensor that is in an electrically grounded condition when sensed liquid is below a predetermined level including:
- a source of electrical potential;
- means connected to said potential source for warning that said liquid is below said predetermined level;
- first means connected between said source of electrical potential and said liquid level sensor for reactively latching a conductive electrical path to ground for said warning means and thereby placing said warning means in an activated condition, when said sensor is in a grounded condition and said electrical potential is applied from said source;
- and
- second means connected between said source of said electrical potential and ground for reactively interrupting the connection between said first reactive means and said sensor following a predetermined period of time after activation by said source of electrical potential.
2 more elements
A low liquid level sensor circuit for use in combination with
- a source of electrical potential;
- switch means between said circuit and said electrical potential source for providing application of said electrical potential to said circuit;
- and
- an electrical switch type liquid level sensor mounted in a liquid container and connected to said circuit to open an electrical ground path when sensed liquid surrounding said sensor is above a predetermined level and to close an electrical ground path when said liquid is below said predetermined level;
- said circuit comprises:
- timing means connected between said switch means and ground for disconnecting said sensor from said circuit after a predetermined period of time following the application of said potential to said circuit by said switch means;
- warning means connected to said switch means for providing a humanly perceivable warning when said sensor provides a closed ground path during said predetermined period of time;
- and
- means connected between said switch means and said sensor during said predetermined period of time for closing a separate ground path to said warning means in the event said sensor provides a closed ground path during said predetermined period of time and in such event, holding said separate ground path closed until said switch means ceases application of said electrical potential.
6 more elements
Dependencies are inferred from the claim text.