WASTE BIN SCALE, LOAD CELL AND METHOD OF MEASURING A WASTE BIN LOAD

• US 20140262552A1
• Filed: 03/14/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Larry D. Santi
• Original Assignee: Larry D. Santi
• Inventors: Santi, Larry D.
• Granted Patent: US 9,562,801 B2
• Time in Patent Office: Days
• US Class Current: 177/1
• CPC Class Codes: G01G 19/083 lift truck scale
• CPC Class Codes: G01G 3/14 measuring variations of electrical resistance G01G3/13 takes precedence
• CPC Class Codes: G01L 1/22 using resistance strain gauges

Abstract

A waste bin scale to measure a cantilevered load carried by lift members of a lift system. The waste bin scale includes a base coupleable to the lift system, a lift member support system; and a plurality of load cells. Each load cell is coupled between the base and the lift member support system, and includes a structural member configured to deform during application of a load applied by the waste bin, where the deformation is indicative of the applied load. Other related waste bin scales, load cells therefor and methods of measuring waste bin scale loads are also provided.

Claims

1. A scale to measure a cantilevered load carried by lift members of a lift system, the scale comprising:

a base coupleable to the lift system;

a lift member support system; and

a plurality of load cells coupled between the base and the lift member support system, each load cell comprising;

a structural member having an aperture extending therethrough which defines at least one pair of offset strain gauge mounting surfaces that are parallel to a horizontal reference plane; and

an arrangement of strain gauges to sense deformations at least at one or more locations on the at least one pair of offset strain gauge mounting surfaces.

2. The scale of claim 1 wherein the lift system is a portion of a waste bin collection vehicle, and wherein the cantilevered load is a waste bin.

3. The scale of claim 1 wherein, for each load cell, the aperture defines an upper strain gauge mounting surface and a lower strain gauge mounting surface that are each parallel to the horizontal reference plane.

4. The scale of claim 1 wherein the aperture is U-shaped or I-shaped and extends completely through a width of the structural member of the load cell.

5. The scale of claim 1 wherein, for each load cell, the aperture extends through a width of the structural member to define at least one thin-walled structural portion adjacent to the aperture.

6. The scale of claim 1 wherein the structural member of each load cell includes at least one thin-walled structural portion with opposing surfaces that are generally parallel to the horizontal reference plane.

7. The scale of claim 1 wherein the structural member of each load cell includes a plurality of distinct apertures extending through a width therewith in series to define at least one thin-walled structural portion between the apertures.

8. The scale of claim 1 wherein each load cell includes a flange for coupling the load cell to the base plate.

9. The scale of claim 1 wherein a lift member support system includes a plurality of load cell cavities for insertably receiving a portion of a respective one of the plurality of load cells.

10. The scale of claim 1 wherein the lift member support system bears on an upper surface of each load cell during operation.

11. The scale of claim 1 wherein the lift member support system is configured to support at least two lift members for lifting waste bins in a cantilevered manner.

12. The scale of claim 1 wherein the structural member of each load cell is coupled to the lift member support system via a dovetail joint.

13. The scale of claim 1, further comprising:

a protective skirt to assist in preventing debris from contacting the load cells during use.

14. A load cell of a scale for measuring at least a portion of a cantilevered load carried by lift members of a lift system, the load cell comprising:

a structural member having at least one aperture extending therethrough that defines at least one pair of offset strain gauge mounting surfaces at each of opposing ends thereof that are parallel to a horizontal reference plane of the load cell; and

a first bridge arrangement of strain gauges including one pair of strain gauges mounted on one of the parallel offset mounting surfaces located at one of the opposing ends of the load cell and including one pair of strain gauges mounted on one of the parallel offset mounting surfaces located at the other one of the opposing ends of the load cell; and

a second bridge arrangement of strain gauges including one pair of strain gauges mounted on one of the parallel offset mounting surfaces located at one of the opposing ends of the load cell and one pair of strain gauges mounted on one of the parallel offset mounting surfaces located at the other one of the opposing ends of the load cell.

15. The load cell of claim 14 wherein the first bridge arrangement of strain gauges includes a first set of strain gauges located on one of parallel offset mounting surfaces at an upper end of the structural member and a second set of strain gauges located on one of parallel offset mounting surfaces at a lower end of the structural member, and wherein the second bridge arrangement of strain gauges includes a first set of strain gauges located on one of parallel offset mounting surfaces at the upper end of the structural member and a second set of strain gauges located on one of parallel offset mounting surfaces at the lower end of the structural member.

16. The load cell of claim 14 wherein the aperture defines an upper strain gauge mounting surface and a lower strain gauge mounting surface that each include a surface generally directed toward each other.

17. The load cell of claim 14 wherein the aperture is U-shaped or I-shaped and extends completely through a width of the structural member.

18. The load cell of claim 14 wherein the aperture extends through a width of the structural member to define at least one thin-walled structural portion adjacent to the aperture.

19. The load cell of claim 14 wherein the structural member includes at least one thin-walled structural portion with opposing surfaces that are generally parallel to the horizontal reference plane.

20. The load cell of claim 14 wherein the structural member of each load cell includes a plurality of distinct apertures extending through a width therewith in series to define at least one thin-walled structural portion between the apertures.

21. The load cell of claim 15 wherein at least some of the strain gauges of the first bridge arrangement are positioned generally opposite of corresponding strain gauges of the second bridge arrangement.

22. The load cell of claim 15 wherein the first set of strain gauges of the first bridge arrangement is located further away from the horizontal reference plane of the load cell than the first set of strain gauges of the second bridge arrangement, and wherein a spread of the first set of strain gauges of the first bridge arrangement is greater than a spread of the first set of strain gauges of the second bridge arrangement.

23. The load cell of claim 22 wherein each of the first set of strain gauges of each of the first and the second bridge arrangements includes one strain gauge arranged to be placed in tension during use and one strain gauge arranged to be placed in compression during use.

24. The load cell of claim 14 wherein the first bridge arrangement of strain gauges exhibits a signal increase when the load is positioned on forks with increasing distance from the load cell and the second bridge arrangement of strain gauges exhibits a signal decrease when the load is positioned on the forks with increasing distance from the load cell.

25. The load cell of claim 24 wherein the arrangement of strain gauges is configured such that a magnitude of the signal increase exhibited by the first bridge arrangement when the load is positioned on the forks with increasing distance from the load cell is about equal to a magnitude of the corresponding signal decrease exhibited by the second bridge arrangement such that a summation of the magnitudes of the signals of the first and second bridge arrangements remains generally constant with changing position of the load along the forks.

26. A method of measuring a load carried by a pair of lift members of a lift system configured to movably position the lift members, the method comprising:

obtaining signals from an arrangement of strain gauges of each of a plurality of load cells that are positioned between the lift system and the lift members, wherein obtaining signals from each load cell includes obtaining, for each load cell, strain gauge signals from a respective first bridge arrangement of strain gauges mounted on parallel horizontal mounting surfaces located at each end of opposing ends of the load cell and obtaining strain gauge signals from a respective second bridge arrangement of strain gauges mounted on parallel mounting surfaces located at each of the opposing ends of the load cell; and

processing the signals to obtain a load value indicative of a load shared by the pair of lift members.

27. The method of claim 26 wherein the first bridge arrangement of strain gauges includes a first set of strain gauges located on one of the parallel offset horizontal mounting surfaces at an upper end of the load cell and a second set of strain gauges located on one of the parallel offset horizontal mounting surfaces at a lower end of the load cell, and wherein the second bridge arrangement of strain gauges includes a first set of strain gauges located on another one of the parallel offset horizontal mounting surfaces at an upper end of the load cell and a second set of strain gauges located on another one of the parallel offset horizontal mounting surfaces at a lower end of the load cell, and wherein a spread of the first set of strain gauges of the first bridge arrangement is greater than a spread of the first set of strain gauges of the second bridge arrangement.

28. The method of claim 27 wherein the strain gauges are arranged such that the load value indicative of the load shared by the pair of lift members is maintained below a threshold accuracy of about 0.5 percent irrespective of a position of the load along a length of the lift members, and wherein, for each load cell, the first bridge arrangement of strain gauges exhibits a signal increase when the load is positioned on the lift members with increasing distance from the load cell and the second bridge arrangement of strain gauges exhibits a signal decrease when the load is positioned on the lift members with increasing distance from the load cell.

29. The method of claim 28 wherein a magnitude of the signal increase exhibited by the first bridge arrangement of strain gauges when the load is positioned on the lift members with increasing distance from the load cell is about equal to a magnitude of the corresponding signal decrease exhibited by the second bridge arrangement of strain gauges such that a summation of the magnitudes of the signals of the first and the second bridge arrangement of strain gauges remains generally constant with changing position of the load along the lift members.