Hollow profile for a weight-in-motion sensor

Patent metadata

Field	Value
Publication number	US-9304032-B2
Application number	US-201214356244-A
Country	US
Kind code	B2
Filing date	Nov 15, 2012
Priority date	Nov 18, 2011
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A WIM (weigh-in-motion) sensor has an oblong hollow profile and includes two force-transmission plates arranged parallel to each other. A tube is arranged between the plates and is integrally formed with the plates and defines a hollow space. Two supports that are arranged opposite one another are formed inside the hollow space, each support extending away from a respective plate and between which a measuring element is received centrally in the tube under preload. The tube includes two tube segments designed to be mirror-symmetrical with respect to each other, which join the plates together and on the inside adjoin the hollow space. The wall thickness of each tube segment has a relatively thick region between at least two relatively thin regions.

First claim

The invention claimed is:

1. An oblong hollow profile for a WIM (weigh in motion) sensor, comprising:
two force-transmission plates arranged parallel to each other,
a tube arranged between these plates is integrally formed with the plates and joins the plates together and forms a hollow space,
two supports that are arranged opposite one another are formed inside the hollow space, each support extending away from a respective plate, the supports being configured for receiving between the supports a measuring element disposed centrally in the tube under preload,
wherein the tube comprises two tube segments, each tube segment includes a wall that has a thickness, each tube segment is shaped to be mirror-symmetrical with respect to the other tube segment, the inside of each tube segment adjoins the hollow space, and wherein the wall thickness of each tube segment has at least two relatively thin regions and a relatively thick region between the two relatively thin regions.

2. The hollow profile according to claim 1 , wherein the wall thickness of each of the tube segments on each side of each of the relatively thin regions comprises at least one relatively thick region.

3. The hollow profile according to claim 1 , wherein every relatively thin region represents a local minimum of the wall thickness.

4. The hollow profile according to claim 1 , wherein the relatively thin regions are configured and disposed to act as flexure hinges with respect to the parallel plates where external force transmission is applied perpendicularly to the parallel plates.

5. The hollow profile according claim 1 , wherein if there is at least one measuring element clamped between the supports, the relatively thin regions are configured and disposed to act as flexure hinges, which as a result of their elasticity are configured and disposed to apply preload to the measuring elements.

6. The hollow profile according to claim 1 , wherein the tube segments are essentially in the shape of circle segments.

7. The hollow profile according to claim 1 , wherein the wall thickness of each of the tube segments has three relatively thin regions and a relatively thick region disposed between each two consecutive thin regions.

8. The hollow profile according to claim 1 , wherein each of the tube segments is mirror-symmetrical relative to a plane B that extends parallel to the plates.

9. The hollow profile according to claim 1 , wherein the cross section of the hollow profile is constant along the entire length L of the hollow profile.

10. An oblong hollow profile for a WIM (weigh in motion) sensor, comprising:
a two force transmission plates arranged parallel to each other,
a tube arranged between these plates is integrally formed with the plates and joins the plates together and forms a hollow space,
two supports that are arranged opposite one another are formed inside the hollow space, each support extending away from a respective plate, the supports being configured for receiving between the supports a measuring element disposed centrally in the tube under preload,
wherein the tube comprises two tube segments, each tube segment includes a wall that has a thickness, each tube segment is shaped to be mirror-symmetrical with respect to the other tube segment, the inside of each type segment adjoins the hollow space, and wherein the wall thickness of each tube segment has at least two relatively thin regions and a relatively thick region between the two relatively thin regions; and
wherein an outer transition region is defined where a respective tube segment joins integrally with a respective one of the plates and the outer transition region between the respective tube segment and the respective plate is provided with an inner radius that is wider by an angle α than it is orthogonally to the plate alignment.

11. The hollow profile according to claim 10 , wherein the cross section of the respective plate in the outer transition region to the respective tube segment defines a local minimum, and following towards the outside in one position increases by a thickness d.

12. The hollow profile according to claim 11 , wherein near the respective outer transition region the cross section of the respective force-transmission plate defines a local maximum, from where the respective force-transmission plate tapers off towards the outside.

13. The hollow profile according to claim 1 , wherein the hollow profile is mirror-symmetrical with respect to a centre plane A extending perpendicularly to the plates.

14. The hollow profile according to claim 1 , wherein the hollow profile is mirror-symmetrical with respect to a centre plane B extending parallel to the plates.

15. The hollow profile according to claim 1 , further comprising a measuring element that is received centrally between the supports under preload.

16. The hollow profile according to claim 15 , further comprising a plurality of measuring elements are held under preload between the supports, wherein the relatively thin regions of the tube segments are extended as a result of bending open so as to apply the preload to the plurality of measuring elements.

17. An oblong hollow profile for a weigh-in-motion sensor, comprising a first force-transmission plate and a second force-transmission plate arranged parallel to the first force-transmission plate,
a tube arranged between these plates and integrally formed with the plates and defining a hollow space, wherein two supports that are arranged opposite one another are formed inside the hollow space, each one of the respective supports extending away from a respective one of the plates, the supports being configured for receiving between the supports a measuring element disposed centrally in the tube under preload, and
wherein the tube comprises two tube segments that are mirror-symmetrical with respect to each other and which join the plates together and on the inside adjoin the hollow space, wherein each tube segment defines a wall having a wall thickness and the wall thickness of each tube segment has at least one relatively thin region with a local minimum, wherein the wall thickness on both opposite sides of this local minimum immediately increases, and wherein this minimum is arranged so as to be closer to the first force-transmission plate.

18. The hollow profile according to claim 17 , wherein the first force-transmission plate is to be installed in a road facing upwards towards the road surface.

19. The hollow profile according to claim 17 , wherein apart from the local relatively thin regions the wall thickness of each tube segment has a constant and homogeneous wall thickness.

20. The hollow profile according to claim 1 , wherein apart from the local relatively thin regions, the wall thickness of each tube segment has a constant and homogeneous wall thickness.

Assignees

• Kistler Holding Ag

Inventors

• Cornu David
• Hofmann Adrian

Classifications

• G01G19/024

  using electrical weight-sensitive devices · CPC title

• G01G3/13 Primary

  having piezoelectric or piezoresistive properties · CPC title

• G01G21/14 Primary

  Beams · CPC title

• G01L1/04

  by measuring elastic deformation of gauges, e.g. of springs · CPC title