Fluid level indicator

• US 6,429,447 B1
• Filed: 06/09/1999
• Issued: 08/06/2002
• Est. Priority Date: 06/09/1999
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Lindsay, Ryan, Nowak, David R.
• Primary Examiner(s): ALLEN, STEPHONE B
• Application Number:
  US09/328,715
• Time in Patent Office: 1,154 Days
• Field of Search: 250/573, 250/577, 250/902, 250/903, 250/905, 732/93, 732/90.R, 340/618, 340/619, 356/133
• US Class Current: 250/573
• CPC Class Codes: G01F 23/2927 for several discrete levels, e.g. with more than one light-conducting sensing element
• CPC Class Codes: Y10S 250/902 with closed light path preset

Abstract

An optical device for measuring a level of a fluid in a container wherein a light conducting body having a top surface and a bottom surface is positioned within the container and into the fluid. A first end of the light conducting body and an oppositely disposed second end, preferably having stepped end surfaces, reflect and refract light in a predetermined manner based upon the fluid level in the container. A resulting brightness of the top surface is therefore inversely proportional to the level of the fluid. Such an optical device is particularly suited toward application to a vehicle fuel tank.

Claims

1. An optical device for measuring a fluid level in a container, the optical device comprising:

a light conducting body having a top surface, a bottom surface, a first end and a second end;

a plurality of stepped end surfaces formed on each of the first end and the second end, the stepped end surfaces arrayed in one or more columns along a periphery of the light conducting body; and

a brightness of the top surface inversely proportional to an amount of the light conducting body submerged in fluid, wherein the fluid level is detected along an entire length of the light conducting body between the top surface to the bottom surface.

2. The optical device of claim 1 further comprising a plurality of ribs formed in the light conducting body between the first end and the second end.

3. The optical device of claim 1 wherein each stepped end surface is formed at an angle between approximately 40°

and 60°

with respect to the top surface.

4. The optical device of claim 1 wherein the bottom surface is spring biased against an inside surface of the container.

5. The optical device of claim 1 further comprising an increased number of stepped end surfaces to improve resolution of a measured fluid level in the container.

6. An optical device for measuring a level of a fluid in a container, the optical device comprising:

a light conducting body having a top surface and a bottom surface positioned within the container and extending into the fluid;

a first end of the light conducting body and an oppositely disposed second end, wherein each of the first end and the second end have a plurality of stepped end surfaces arrayed in one or more columns along a periphery of the light conducting body and forming a generally tapered profile such that the bottom surface is narrower than the top surface; and

a brightness of the top surface inversely proportional to the level of the fluid, wherein the fluid level is detected along an entire length of the light conducting body between the top surface to the bottom surface.

7. The optical device of claim 6 further comprising a light source positioned adjacent the top surface of the light conducting body.

8. The optical device of claim 6 wherein at least one of the stepped end surfaces is colored.

9. The optical device of claim 6 wherein at least one of the stepped end surfaces is formed with an angled surface.

10. The optical device of claim 6 wherein the bottom surface is spring biased with respect to an inside surface of the container.

11. The optical device of claim 6 further comprising a light receiving device positioned adjacent the top surface of the light conducting body.

12. The optical device of claim 11 wherein the light receiving device comprises an electronic sensor.

13. An optical device for measuring a level of a fluid in a container, the optical device comprising:

a light conducting body extending into the fluid;

a plurality of stepped end surfaces formed along an outer edge of the light conducting body; and

a brightness of the light conducting body proportional to the level of the fluid, wherein the fluid level is detected along an entire length of the light conducting body between the top surface to the bottom surface.

14. The optical device of claim 13 wherein the brightness varies in a top of the light conducting body as the level of the fluid changes.

15. The optical device of claim 14 further comprising a light receiving device positioned adjacent the top of the light conducting body.

16. An optical device for measuring a fluid level in a container, the optical device comprising:

a light conducting body having a top surface, a bottom surface, a first end and a second end;

a plurality of stepped end surfaces formed on each of the first end and the second end, wherein the first end is separated from the second end by two generally planar surfaces; and

a brightness of the top surface inversely proportional to an amount of the light conducting body submerged in fluid.

17. An optical device for measuring a fluid level in a container, the optical device comprising:

a light conducting body having a top surface, a bottom surface, a first end and a second end, wherein an angled cutout is formed through the light conducting body adjacent to the top surface;

a plurality of stepped end surfaces formed on each of the first end and the second end; and

a brightness of the top surface inversely proportional to an amount of the light conducting body submerged in fluid.

18. An optical device for measuring a fluid level in a container, the optical device comprising:

a light conducting body having a top surface, a bottom surface, a first end and a second end;

a plurality of stepped end surfaces formed on each of the first end and the second end, wherein the stepped end surfaces are aligned in at least two columns along each of the first end and the second end; and

a brightness of the top surface inversely proportional to an amount of the light conducting body submerged in fluid.

19. The optical device of claim 18 wherein the stepped end surfaces in each column are staggered with respect to the stepped end surfaces in each other column.