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US4720920A Expired / Lapsed US ⏱️ 0.0 years remaining

Level with electronic signals

Assignee: Individual
•
Filing: 1982-01-28
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Granted: 1988-01-26
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Expires: 2002-01-28
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Abstract

Abstract A device that may be of different shapes and sizes to function as a level that emits an audio and visual signal when the device is level or parallel with gravity. It will also emit the same signals when the level is put in a vertical position and the device is plumb in one dimension; while at the same time will emit a different audio and visual signal when the level is moved and the bubble or amalgam will flow to the center of the other glass tube thus indicating that the other plane is level. In essence, both sets of signals will activate when the level is in true vertical position. The audio and visual signals are activated by D.C. current supplied by a dry cell battery. The liquid leveling agent is a drop of amalgam enclosed in a glass tube that is embedded in the body of the level. The contact points are also in the inner walls of the glass tube and traverse their circumference and at one point, they penetrate the walls of the glass tube to connect the outer surface; and are spaced the distance of the liquid amalgam when it rests in its extended state. The spaced contact points are a part of a simple open parallel circuit switch. Closing of the circuit will result when the amalgam flows to touch the contact points simultaneously when the device is level or plumb thus activating the electronic beep and the light signal.

Inventors

  • 👤 Arthur L. Tudek

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 10:43
CPC Classifications
G; G01; G01C; G01C9/00; G01C9/02; G01C9/06

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 93 words
A level for gauging predetermined horizontal and vertical planes, comprising three mercury type switches disposed at right angles to each other, two of said switches when simultaneously operated indicating said predetermined vertical plane and two other of them when simultaneously operated, indicating said predetermined horizontal plane, two of said mercury type switches being arranged closely together in cruciform relationship and the other extending along the longitudinal axis of the level and wherein the second switch of each of said two cannot be actuated until the first switch is bridged and actuates a signal.
Claim 2
Dependent Claim 93 words
A level for gauging predetermined horizontal and vertical planes, comprising three mercury type switches disposed at right angles to each other, two of said switches when simultaneously operated indicating said predetermined vertical plane and two other of them when simultaneously operated, indicating said predetermined horizontal plane, two of said mercury type switches being arranged closely together in cruciform relationship and the other extending along the longitudinal axis of the level and wherein the second switch of each of said two cannot be actuated until the first switch is bridged and actuates a signal.

References Cited (Backward Citations)

US3172212A Cited
US3786472A Cited
US4003134A Cited
US4079521A Cited
US4244117A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-01-25 1991-07-27 1992-01-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-01-25 1995-07-27 1996-01-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-01-25 1999-07-27 2000-01-26 $7700.00 Window Closed / Lapsed

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