Two-axis quartz fiber passive tilt meter

• US 4,812,654 A
• Filed: 12/29/1986
• Issued: 03/14/1989
• Est. Priority Date: 12/29/1986
• Status: Expired due to Fees

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Araujo, Richard K.
• Primary Examiner(s): Howell, Janice A.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/946,885
• Time in Patent Office: 806 Days
• Field of Search: 250/338 R, 250/341, 33/391, 33/392, 33/365, 33/348, 33/366
• US Class Current: 250/338.1
• CPC Class Codes: G01C 9/06 Electric or photoelectric indication or reading means
• CPC Class Codes: G01C 9/14 movable in more than one direction

Abstract

A two-axis quartz fiber passive tilt meter which includes housing and a quartz fiber suspended from the housing for conducting radiation and emitting the radiation from a distal end thereof. A pendulous mass is suspended from the quartz fiber and a damping fluid in the housing surrounds the quartz fiber and the mass. A detector senses the position of the spot of radiation emitted from the quartz fiber.

Claims

1. A two-axis quartz fiber passive tilt meter comprising:

a housing;

a quartz fiber suspended from said housing for conducting radiation and emitting said radiation from a distal end thereof;

a pendulous mass suspended from said quartz fiber;

a damping fluid in said housing surrounding said quartz fiber and said mass, said damping fluid having an index of refraction close to that of said quartz fiber for optically cladding said fiber; and

detector means for sensing the position of a spot of radiation emitted from said quartz fiber.

2. The tilt meter of claim 1 further including a mechanical stop mounted within said housing proximate said mass for limiting horizontal movement of said mass to limit bending of said quartz fiber.

3. The tilt meter of claim 2 in which said mechanical stop includes tube means which surround said quartz fiber and said pendulous mass.

4. The tilt meter of claim 3 further including fluid communication means interconnecting said tube means and the interior of said housing for transmitting damping fluid therethrough.

5. The tilt meter of claim 1 in which said quartz fiber is disposed through said pendulous mass.

6. The tilt meter of claim 1 in which said pendulous mass is suspended proximate the distal end of said quartz fiber.

7. The tilt meter of claim 1 in which said tilt meter is constructed of nonmagnetic material.

8. The tilt meter of claim 1 further including a source of radiation mounted in said housing for introducing radiation to said fiber.

9. The tilt meter of claim 8 in which said source of radiation includes a light-emitting diode.

10. The tilt meter of claim 1 in which infrared radiation is conducted through said quartz fiber.

11. The tilt meter of claim 10 in which said infrared radiation includes a wavelength of 880 nanometers.

12. The tilt meter of claim 1 in which said detector means includes a sensor and lens means for directing said radiation emitted by said quartz fiber to a spot on said sensor.

13. The tilt meter of claim 1 in which said detector means includes a four quadrant detector.

14. The tilt meter of claim 1 further including a window mounted in said housing between the light-emitting end of said quartz fiber and said detector means.