WEIGHING DEVICE

• US 3,734,216 A
• Filed: 09/16/1971
• Issued: 05/22/1973
• Est. Priority Date: 09/21/1970
• Status: Expired due to Term

• Current Assignee: Flintab AB Vasteras Sweden
• Original Assignee: Kjell Helge Nordstrom, Rune Nils Allan Flinth
• Inventors: Nordstrom, Kjell Helge, Flinth, Rune Nils Allan
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US05/181,031
• Time in Patent Office: 614 Days
• Field of Search: 177/134-136,163,211 73/141A
• US Class Current: 177/136
• CPC Class Codes: G01G 19/042 having electrical weight-sensitive devices
• CPC Class Codes: G01G 19/047 using electrical weight-sensitive devices
• CPC Class Codes: G01G 3/1404 combined with means to connect the strain gauges on electrical bridges

Abstract

A weigh device for static or dynamic weighing of railway guided vehicles comprising a weigh rail fixedly supported at both ends and strain gages positioned on the rail a predetermined distance apart and arranged such that the gages are essentially insensitive to bending moments and sense the strain in the rail in proportion to the shear forces imposed on the rail when a load is applied to the weigh rail.

Claims

1. A weigh device for weighing vehicles adapted to be supported on and movable along a rail system, said weigh device comprising a weigh rail having a longitudinal neutral axis in the rail system adapted to cooperate with and support the wheel of a vehicle, support means cooperating with said weigh rail to provide spaced apart relatively rigid sections with a deflectable weigh section between said rigid sections, said deflectable weigh section having a bending moment curve when loaded by the wheel of a vehicle which includes inflection points at which the bending moments are zero, at least two strain sensing means secured to said weigh section and arranged to sense the shear in said weigh section, each of said strain sensing means being positioned on the longitudinal neutral axis of said weigh section and at an inflection point whereby said strain sensing means are effective to sense the shear in said weigh section independent of bending moments.

2. The weigh device of claim 1 wherein said weigh section includes stiffening means at the center portion thereof to prevent bending of said center portion under the load of a wheel.

3. The weigh device of claim 1 wherein said weigh section includes transition means in the wheel engaging surface with said strain sensing means and operative to minimize shock loading on said sensing means.

4. The weigh device of claim 1 wherein said weigh section has a generally I-shaped cross-section at the locations of said strain sensing means with said strain sensing means being secured to the web thereof.

5. The weigh device of claim 1 and further including connection means at either end of said weigh rail, said connection means comprising a deflectable, joint connecting said weigh rail to the rail system.

6. The weigh device of claim 5 wherein each of said deflectable joints comprises a pair of spaced apart slots defining a stiff section therebetween with each of said slots forming a friction free joint.

7. The weigh device of claim 1 wherein said support means includes reinforcing means connected to said weigh rail.

8. The weigh device of claim 5 wherein said support means includes reinforcing means connected to said weigh rail, said deflectable joints being outside of the rigid sections provided by said reinforcing means.

9. The weigh device of claim 1 and including means for maintaining the inflection points at known locations along the weigh section irrespective of variations in the forces present in the rail system.

10. The weigh device of claim 9 wherein said latter means includes deflectable joints between said rigid sections and the rail system.

11. The weigh device of claim 1 and including means for maintaining the inflection points at known locations along tHe weigh section irrespective of variations in the positioning of the load on the weigh section.

12. The weigh device of claim 11 wherein said latter means comprises stiffening means on said weigh section extending for a substantial distance on either side of the center of the weigh section to provide a stiffened center portion which resists bending when a load is applied thereto.

13. The weigh device of claim 12 wherein one of said strain sensing means is located midway between one of the rigid sections and the stiffened center portion and the other of said strain sensing means is located midway between the other of the rigid sections and the stiffened center portion.

14. A weigh device for weighing railway guided vehicles, said device comprising, a weigh rail having a longitudinal neutral axis adapted to be inserted in a rail system to form a continuous part of such system, said weigh rail including spaced apart stiffened sections defining a weigh section therebetween, said weigh section having a bending moment curve when loaded at a predetermined location which includes inflection points at which the bending moments are zero, at least two strain sensing means secured to said weigh section with said strain sensing means being arranged to sense the shear in said weigh section, each of said strain sensing means being positioned on the neutral axis of said weigh section and at an inflection point whereby said strain sensing means are operative to produce signals proportional to the shear in said weigh section.

15. The weigh device of claim 14 wherein said weigh section has a generally I-shaped cross-section at the location of said strain sensing means with said strain sensing means being secured to the web thereof.

16. The weigh device of claim 14 wherein said predetermined location is defined by a stiffened center portion of said weigh section and along which the load may be applied at various locations.

17. The weigh device of claim 16 and further including connection means at the ends of said weigh rail, said connection means comprising a deflectable joint for connecting said weigh rail to the rail system.

18. A device for weighing of railway guided vehicles comprising at least one elongated rail section, substantially rigid connection means interconnecting spaced apart portions of said rail section whereby said interconnected portions are substantially fixedly restrained, said rail section including at least one flexible portion between said spaced apart portions, said flexible portion having a bending moment curve when loaded by the wheels of a vehicle which includes inflection points at which the bending moments are zero, and strain sensing means arranged on said flexible portion with the center line thereof substantially coinciding with the inflection points of the bending deflection curve of said flexible portions.

19. A device for weighing of railway guided vehicles comprising at least one elongated rail section having a vehicle supporting upper surface, at least two strain sensing means secured to said rail section such that they are influenced by substantially only shear stresses in the section with the sensing means being longitudinally spaced apart to define a measuring section therebetween and within which the load from at least one vehicle wheel can influence said sensing means, and friction free joint means at either end of said rail section, said friction free joint means comprising a pair of sapced apart slots formed in the undersurface of said rail sections whereby the rail section has a smooth continuous vehicle supporting upper surface.