Remote level sensing instrument

• US 4,154,000 A
• Filed: 07/19/1977
• Issued: 05/15/1979
• Est. Priority Date: 01/12/1976
• Status: Expired due to Term

• Current Assignee: Brunton
• Original Assignee: Brunton
• Inventors: Kramer, Melvin G.
• Primary Examiner(s): Phillips, Charles E.
• Application Number:
  US05/817,006
• Time in Patent Office: 665 Days
• Field of Search: 33/366, 250/231 R, 250/575, 250/577
• US Class Current: 33/366.14
• CPC Class Codes: G01C 9/06 Electric or photoelectric indication or reading means
• CPC Class Codes: G01C 9/26 Details

Abstract

Concentrated light beams from two or more sources are passed through a spirit level mounted in a portable housing and the presence of the light beam columns after passing through the level is detected to indicate on-level or the direction of off-level for a remote plane or surface. In one form, detection circuitry selectably lights one or a pair of indicator lamps appropriately arrayed on a display panel for establishing that the remote spirit level is in a level orientation or the direction of out-of-level. The detector circuitry can include cross-coupling to prevent an erroneous indication of the direction of out-of-level. In another form, multiple pairs of concentrated light sources and detectors are arrayed along the length of the spirit level and digital circuitry converts the detected outputs into a direct digital display and/or into a format appropriately useful for other digital data handling equipment.

Claims

1. Apparatus for sensing orientation of a remote surface with respect to level comprising:

an elongated transparent vial enclosing a fluid and a bubble, said vial being formed along the length thereof as a segment of an arc,

a portable housing means for establishing a reference line parallel to the surface to be sensed, said housing further including means mounting said vial therein with the elongated axis of said vial and said reference line defining a plane perpendicular to the surface to be sensed, said mounting means positioning said vial with the central portion of said arc higher than the ends of said vial when vial is level,

a plurality of light beam channels within said housing and each including means for directing a concentrated column of light against one sidewall of said vial so that said light column will pass through the vial and said fluid and will exit from the sidewall of said vial at a second point along an arc defined by the cross-section of said vial, each said column of light exiting in a first direction after passing through said bubble and in a second direction after passing through said fluid, said light beam channels being arcuately arranged along said vial and spanning a distance greater than the length of said bubble, two of said light beam channels of said plurality being directed towards said one sidewall in proximity to but spaced from respective ends of said bubble when said vial is level, said plurality of light beam channels each further including a light sensitive device responsive to a light column from one of said exit directions while being isolated from light emanating from any other direction so that the electrical conductivity state of each said light sensitive device reflects the position of said bubble within the said vial,

circuit means responsive to the electrical conductivity states of said light sensitive devices for generating first and second output signals representing the direction and magnitude of displacement of said vial relative to the level attitude of said reference line, and

overrange detector means responsive to the electrical conductivity states of said light sensitive devices associated with said two of said light beam channels for generating an output signal when said bubble is out of the detectable range of the other of said plurality of light beam channels.

2. Apparatus in accordance with claim 1 wherein said light beam channels are arranged for directing said light columns against said one sidewall so that said columns are refracted in passing through said fluid in proximity to opposite ends of said bubble when said vial is horizontally level, said light sensitive devices each including an aperture aligned with the direction of refracted light exiting from said vial from respective ends of said bubble when said vial is level.

3. Apparatus in accordance with claim 1 which further includes a display having a first and second lamp devices connected for actuation in response to respective said first and second output signals for producing a visible output indication of the direction the surface is out of level.

4. Apparatus in accordance with claim 3 which includes an electrical power source, switch means for selectably coupling said power source to said circuit means, and a third lamp device energized whenever said power source is coupled to said circuit means by said switch means.

5. Apparatus in accordance with claim 4 wherein said display includes a panel mounting said first and second lamp devices above and on opposite sides of said third lamp device in a generally V-shaped configuration.

6. Apparatus in accordance with claim 1 wherein said circuit means includes means continuously operable during the presence of one of said output signals for preventing generation of the other said output signal.

7. Apparatus in accordance with claim 1 wherein said plurality of light beam channels are arrayed with equal spacing therebetween along said vial and at least one said channel is located so as to be interposed by said bubble whenever said vial is level, whereby the electrical conductivity state of said light sensitive devices defines a multiple bit digital character representative of the orientation of the surface relative to level in the given direction.

8. Apparatus in accordance with claim 7 which further includes indicator means responsive to digital input signals for producing a visible display corresponding thereto, and means for converting said electrical conductivity states into digital signals for said indicator means to produce a display reflecting the orientation of the surface relative to level in the given direction.

9. Apparatus in accordance with claim 1 wherein said overrange detector means includes a logic circuit means whereby the state of one of said two of said light beam channels and the state of one of the other of said plurality of light beam channels is operative to generate a sign signal representative of the direction of said bubble along said vial.

10. A system for providing a remote indication of the orientation of a surface relative to level in a given direction comprising:

means retaining a light modifying element for movement along a predetermined path with said element continuously assuming a position reflecting level,

housing means including means engageable with the surface to be measured for establishing a reference line, said housing means further having means for mounting said element so that said predetermined path in conjunction with said reference line defines a plane perpendicular to the surface to be measured, said element being located in an intermediate position along said predetermined path when the surface is level,

at least one light source,

a first opaque plate positioned parallel to said plane and having a pair of apertures and a plurality of additional apertures opening therethrough with each said aperture forming light from said source into a column perpendicular to said plane in a location so that said light column crosses said predetermined path of said element, said apertures of said pair being positioned for directing said light columns therefrom in locations in proximity to respective ends of said element along said predetermined path when said element is in said intermediate position,

a second opaque plate positioned parallel to said plane and on the side thereof opposite said first plate and having a pair of apertures and a plurality of additional apertures therethrough in alignment with respective said light columns exiting from said plane,

a plurality of light sensitive devices aligned with said pair of apertures and plurality of additional apertures in said second opaque plate each capable of changing electrical conductivity state in response to light impinging thereon from a light column passing through an aperture aligned with each respective light sensitive device,

circuit means responsive to the electrical conductivity states of said plurality of said light sensitive devices for said plurality of additional apertures for producing a digital output signal representing the location of said element along said predetermined path so as to indicate the orientation of said reference line relative to level, and

overrange circuit means associated with said light sensitive devices for said pair of said apertures in said first and second opaque plates for generating an output signal to indicate that said element is out of the detectable range of said plurality of additional apertures and associated light sensitive devices.

11. A system in accordance with claim 10 wherein said circuit means includes means for converting said digital output signal to a signal indicating the amount and direction said light modifying element is displaced along said predetermined path from said intermediate position.

12. A system in accordance with claim 10 which further includes means for transforming a digital character at the input thereof into a corresponding visually readable display, said circuit means further including means for transposing said digital output signal into a digital character for said display means input for causing said display means to register a visually readable output reflecting the orientation of the surface relative to level in the direction of said reference line, said output signal of said overrange circuit means causing said display means to indicate that said element is out of the detectable range.

13. A system in accordance with claim 12 wherein said overrange circuit means includes means responsive to the electrical conductivity state of said additional light sensitive device for causing said display means to indicate the direction said element is out of the detectable range.