Light wave conductor-bending sensor with sliding rails for monitoring bridge structures or the like

• US 4,972,073 A
• Filed: 01/23/1990
• Issued: 11/20/1990
• Est. Priority Date: 02/02/1989
• Status: Expired due to Term

• Current Assignee: Felten & Guilleaume Energietechnik AG (Eaton Corporation PLC.)
• Original Assignee: Felten & Guilleaume Energietechnik AG (Eaton Corporation PLC.)
• Inventors: Lessing, Rainer
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Messinger, Michael
• Application Number:
  US07/468,563
• Time in Patent Office: 301 Days
• Field of Search: 250/227.14, 250/227.15, 250/227.16, 250/227.17, 250/227.18, 250/231.10, 250/231.19, 250/239, 73/800, 73/786, 350/96.15, 350/96.29
• US Class Current: 250/227.16
• CPC Class Codes: G01B 11/18 using photoelastic elements
• CPC Class Codes: G01M 11/086 Details about the embedment of the optical fiber within the DUT
• CPC Class Codes: G01M 5/0008 of bridges
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection

Abstract

A measuring device with a light wave conductor-bending sensor for monitoring bridge structures comprises a light emitter and a light receiver, a multi-mode light wave conductor arranged to extend along a structural part and having two ends connected with the light emitter and the light receiver, respectively, an elongated plate having a lower side arranged to be placed on and connected with the structural part and also having an upper side provided with a longitudinal groove, two sliding rails arranged in the longitudinal groove and having outer ends fixed to the plate and inner ends spaced from one another to form an intermediate space and movable relative to the plate. The light wave conductor is fixed with one of the sliding rails, then extends through the intermediate space and forms a freely movable curve, and then exztends along and is fixed to the other of the movable rails.

Claims

1. A measuring device with a light wave conductor bending sensor for monitoring bridge structures, comprising a light emitter and a light receiver;

a multi-mode light wave conductor arranged to extend along a structural part and having two ends connected with said light emitter and said light receiver, respectively;

an elongated plate having a lower side arranged to be placed on and connected with the structural part and also having an upper side provided with a longitudinal groove;

two sliding rails arranged in said longitudinal groove and having outer ends fixed to said plate and inner ends spaced from one another to form an intermediate space and movable relative to said plate, said light wave conductor being fixed with one of said sliding rails, then extends through said intermediate space and forms a freely movable curve, and then extends along and is fixed to the other of said movable rails.

2. A measuring device as defined in claim 1, wherein said plate is composed of a material which is the same as that of the structural part.

3. A measuring device as defined in claim 1, wherein said plate is composed of a material which is similar to that of said structural part.

4. A measuring device as defined in claim 1, wherein said lower side of said plate is flat.

5. A measuring device as defined in claim 1, wherein each of said sliding rails has a width equal to substantially one-third of a width of said plate and a length equal to substantially one-third of a length of said plate.

6. A measuring device as defined in claim 1, 2 wherein said sliding rails are arranged so that a free space is provided at each end of said plate.

7. A measuring device as defined in claim 1;

and further comprising means for connecting said plate with the structural part and including gluing means.

8. A measuring device as defined in claim 1;

and further comprising means for fixing said light wave conductor to said sliding rails and including gluing means.

9. A measuring device as defined in claim 1, wherein said plate has a longitudinal axis, said light wave conductor having a first portion located at one side of said longitudinal axis, a second portion located at the other side of said longitudinal axis, and a loop connecting said portions with one another, said portions being mirror-symmetrical relative to one another.

10. A measuring device as defined in claim 1, wherein each of said sliding rails has an outer region and an inner region, said light wave conductor being surrounded in said outer region with a polyvinylchloride hose and being surrounded in said inner region by a steel pipe, said hose and said pipe being connected with said rails, said light wave conductor being surrounded by a silicon hose in the region of said curve.

11. A measuring device as defined in claim 10, wherein said light wave conductor is surrounded by a hard secondary coating.

12. A measuring device as defined in claim 10, wherein said steel pipe has a thickness of substantially 0.6 mm.

13. A measuring device as defined in claim 1, wherein said plate has a raised edge provided with a groove;

and further comprising a seal arranged in said groove;

a plate-shaped cover mounted on said plate; and

a housing for said emitter and said receiver mounted on said plate, said plate having a hole through which said light wave conductor extends.

14. A measuring device as defined in claim 13;

and further comprising means for mounting said cover and said housing on said plate and including screw means.

15. A measuring device as defined in claim 13, wherein said seal is formed as a silicon sealing member.

16. A measuring device as defined in claim 13, wherein said light wave conductor is a sensor light wave conductor;

and further comprising a reference light wave conductor which is identical to said sensor light wave conductor.

17. A measuring device as defined in claim 16, wherein said emitter includes an emitting diode for both said light wave conductors, said receiver including two photodiodes with integrated amplifiers for said light wave conductors, said housing accommodating a first housing for said emitting diode and second housings for said photodiodes.

18. A measuring device as defined in claim 16, wherein said housing has an end surface provided with a plug bush for an electrical conduit.

19. A measuring device as defined in claim 13, wherein said plate, said cover and said housing are composed of aluminum.