Apparatus and method for weighing rolling railcars

• US 4,416,342 A
• Filed: 01/04/1982
• Issued: 11/22/1983
• Est. Priority Date: 03/26/1981
• Status: Expired due to Term

• Current Assignee: Kilo-Wate Incorporated
• Original Assignee: Suzanne Kerr, Snead
• Inventors: Snead, Edwin D.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US06/336,893
• Time in Patent Office: 687 Days
• Field of Search: 177/163, 177/211
• US Class Current: 177/163
• CPC Class Codes: G01G 19/047 using electrical weight-sensitive devices

Abstract

A weigh section of a railway track consists of two unsupported spans of conventional rail, produced by removing two adjacent supporting ties for example. The span of the unsupported rails is approximately 64 inches, less than the minimum distance between adjacent axles of a railcar. Four strain gauges are mounted on the under surface of the unsupported rail span of each rail, the four gauges consisting of two pairs of outboard and inboard gauges located in respective halves of the unsupported span. The outputs of the four strain gauges for an unsupported span are summed by adding the outputs of the inboard gauges and subtracting the outputs of the outboard gauges. This sum produces a constant value representative of the load supported on the rail as the axle load moves between the two inboard gauges. A limit switch tripped by a wheel of each axle activates a computer. The computer accumulates a plurality of sum samples while an axle moves between the two inboard gauges, averages the sum samples to produce average load value for each axle of a car, and converts the accumulation of average values to the total car weight.

Claims

1. A system for weighing railcars in motion comprising

a length of rail of generally uniform cross section supported at opposite ends in the manner of conventional rail;

said length of rail including an unsupported section intermediate its ends, defining a weigh span;

said weigh span having a length less than the minimum distance between adjacent axles of said railcars;

means mounted on said weigh span at four respective measuring points therealong for producing electric signals corresponding to the respective bending moments at said measuring points;

said four measuring points comprising two pairs of points, each pair consisting of an outboard and inboard point, and each pair being disposed in a respective half of said weigh span;

the points of said pairs being spaced approximately the same distance from each other;

means for summing the signals of said four signal producing means while a railroad axle moves between said two inboard measuring points.

2. A system as set forth in claim 1

said summing means comprising means for adding said signals of said inboard signal producing means and for subtracting said signals of said outboard signal producing means.

3. A system as set forth in claim 1

said inboard points being spaced from each other a distance at least one-third the length of said weigh span.

4. A system as set forth in claim 1

said inboard points being shaped from each other a distance allowing axle traversal time of about 0.26 seconds at a railcar velocity of 53 inches/second.

5. A system as set forth in claim 1

said inboard points being spaced from each other at least twice the distance represented by the St. Venant'"'"'s distortion range.

6. A system as set forth in claim 1

said outboard points being spaced from the respective ends of said weigh span a distance to be free of St. Venant'"'"'s distortion.

7. A system as set forth in claim 1

said signal producing means comprising strain gauges.

8. A system as set forth in claim 1

a pair of said weigh spans aligned laterally in the two rails of a railroad track.

9. A system as set forth in claim 1

fulcrum support means for supporting said length of rail at the ends of said weigh span, said fulcrum support means defining the length of said span;

said fulcrum support means comprising conventional ties and tie plates.

10. A system as set forth in claim 1

said signal producing means comprising strain gauges mounted on the under surface of said weigh span to detect the longitudinal expansion or contraction of said under surface.

11. A system as set forth in claim 10

said strain gauges being connected in a bridge circuit for summing the output thereof and producing a bridge circuit output corresponding to the load supported by said weigh span.

12. A system as set forth in claim 1

means for detecting said summed moments in a plurality of successive samplings while a railcar axle moves between said inboard measuring points;

and means for averaging said samplings to produce an average sum of moments representing the weight supported by a railcar wheel.

13. A system as set forth in claim 12

means for summing said average sum of moments for each wheel of said railcar, to produce a sum representing the total weight of said railcar.

14. A system as set forth in claim 1

said length of rail comprising conventional rail.

15. A system as set forth in claim 14

said length of conventional rail having a uniform unmodified cross section.

16. A method for weighing railcars in motion comprising the steps

supporting a length of rail of generally uniform cross section at its opposite ends in the manner of conventional rail, thereby providing an unsupported section of said rail intermediate its ends to define a weigh span;

spacing the supports for said length of rail to provide said weigh span with a length less than the minimum distance between adjacent axles of said railcars;

measuring the bending moments, imposed on said weigh span by a railcar wheel load, at four measuring points therealong consisting of two pairs of outboard and inboard points;

positioning one of said pairs of measuring points in each half of said weight span, with the points of said pairs spaced approximately the same distance from each other;

summing the bending moments at said four measuring points.

17. A method as set forth in claim 16 including

summing said bending moments when a wheel axle is moving between said two inboard measuring points.

18. A method as set forth in claim 16 including

summing said bending moments at said four measuring points by adding the inboard moments and substracting the outboard moments.

19. A method as set forth in claim 16 including

determining a measurement span between said two measuring points, which measurement span is free from the St. Venant distortion range at said inboard measuring points;

and summing said bending moments when the wheel axle is moving within said measurement span.

20. A method as set forth in claim 16 including

spacing apart said inboard measuring points about at least 1/3 the length of said weigh span.

21. A method as set forth in claim 16 including

detecting said summed moments in a plurality of successive samplings;

and accumulating and averaging said samplings to produce an average sum of moments representing the weight supported by said wheel.

22. A method as set forth in claim 16 including

providing of said lengths of rail including said unsupported weigh span in each of a pair of side-by-side rails to be traversed simultaneously by the wheels of a common railcar axle;

and measuring the bending moments of both spans in the same manner.

23. A method as set forth in claim 16 including

mounting a strain gauge on the under surface of said weigh span at each of said four measuring points in a manner to detect the longitudinal expansion or contraction of said under surface, for producing electric output signals corresponding to the bending moments at said measuring points;

and summing electrically said output signals.

24. A method as set forth in claim 16 including

supporting said length of rail at the ends of weigh span by fulcrum supports in the form of conventional ties and tie plates, to define the ends of said weigh span.

25. A method as set forth in claim 16 including

spacing apart said inboard points about twice the distance of the St. Venant distortion range.

26. A method as set forth in claim 25 including

accumulating said average sum of moments for each wheel of said railcar, said accumulated sum representing the total weight of said railcar.

27. A method as set forth in claim 16 including

providing a length of conventional rail as said supported length of rail.

28. A method as set forth in claim 27 including

providing said length of conventional rail having a uniform, unmodified cross section.