Load cell to frame interface for hospital bed

• US 7,176,391 B2
• Filed: 08/24/2005
• Issued: 02/13/2007
• Est. Priority Date: 09/13/2004
• Status: Expired due to Fees

• Current Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Original Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Inventors: Figel, Gregory J., Metz, Darrell L.
• Primary Examiner(s): Gibson; Randy W.
• Application Number:
  US11/210,653
• Publication Number:
  US 20060059814A1
• Time in Patent Office: 538 Days
• Field of Search: 177/144, 177/DIG.9
• US Class Current: 177/144
• CPC Class Codes: A61G 2203/32 for force
• CPC Class Codes: A61G 7/012 raising or lowering of the whole mattress frame A61G7/005, A61G7/008 take precedence
• CPC Class Codes: A61G 7/015 divided into different adjustable sections, e.g. for Gatch position
• CPC Class Codes: A61G 7/0527 Weighing devices
• CPC Class Codes: G01G 19/445 in a horizontal position
• CPC Class Codes: Y10S 177/09 Scale bearings

Abstract

A load cell apparatus has a load cell adapted to couple to a first structure. The load cell comprises a load cell body and a sensor. The sensor provides an output signal indicative of an amount of weight applied to the load cell. A stud extends away from the load cell body. The load cell apparatus has a stud receiver including a space in which a portion of the stud is received. A set of rollers are coupled to one of the stud receiver and a second structure and contact the other of the stud receiver and the second structure.

Claims

1. A combination comprising

a first structure,

a second structure,

a load cell coupled to the first structure, the load cell comprising a load cell body and a sensor, the sensor providing an output signal indicative of an amount of load applied to the load cell,

a stud extending away from the load cell body,

a stud receiver having a space in which a portion of the stud is received, and

a set of rollers coupled to one of the stud receiver and the second structure and contacting the other of the stud receiver and the second structure.

2. The combination of claim 1, wherein the space comprises a substantially cylindrical bore in which the portion of the stud is received.

3. The combination of claim 2, wherein at least part of the portion of the stud received in the substantially cylindrical bore is substantially cylindrical and has a stud diameter smaller than a bore diameter of the substantially cylindrical bore.

4. The combination of claim 1, wherein the space comprises a substantially triangular bore in which the portion of the stud is received.

5. The combination of claim 4, wherein at least part of the portion of the stud received in the substantially triangular bore is substantially cylindrical.

6. The combination of claim 5, wherein the substantially triangular bore is defined, in part, by two inclined surfaces that engage different portions of the stud along a pair of contact lines.

7. The combination of claim 4, wherein the substantially triangular bore has three apexes that are spaced from the stud.

8. The combination of claim 1, wherein the stud receiver rotates about the stud when the second structure tilts relative to the first structure.

9. The combination of claim 1, wherein the set of rollers roll upon the second structure when the second structure tilts relative to the first structure.

10. The combination of claim 1, wherein the stud extends substantially horizontally relative to the load cell body along a first substantially horizontal axis and each roller of the set of rollers is rotatable about a respective second substantially horizontal axis.

11. The combination of claim 10, wherein the set of rollers comprises at least two rollers and the second substantially horizontal axes of the at least two rollers define a plane situated above the first substantially horizontal axis.

12. The combination of claim 1, wherein the stud receiver comprises a pair of roller-receiving pockets, the set of rollers comprises a pair of rollers, and at least a portion of each roller of the pair of rollers is received in a respective pocket of the pair of roller-receiving pockets.

13. The combination of claim 12, wherein the stud receiver comprises a horizontal wall underlying the pair of roller-receiving pockets and a vertical wall situated between the pair of roller-receiving pockets.

14. The combination of claim 12, wherein the roller-receiving pockets are each open at a top surface and at respective end surfaces of the stud receiver.

15. The combination of claim 1, wherein the stud receiver has a top surface and a part of each roller of the set of rollers extends upwardly beyond the top surface of the stud receiver.

16. The combination of claim 1, wherein the stud receiver has a pair of vertical walls and at least part of each roller of the set of rollers are situated between the pair of vertical walls.

17. The combination of claim 16, further comprising a set of shafts extending across a gap defined between the pair of vertical walls and each roller of the set of rollers is mounted for rotation on a respective shaft of the set of shafts.

18. The combination of claim 17, further comprising a set of bushings, each bushing being interposed between a respective roller of the set of rollers and the associated shaft.

19. The combination of claim 17, further comprising a set of bearings with rolling elements, each bearing being interposed between a respective roller of the set of rollers and the associated shaft.

20. The combination of claim 17, wherein a first vertical wall of the pair of vertical walls has a first set of holes, a second vertical wall of the pair of vertical walls has a second set of holes, each shaft has a first end received in a respective hole of the first set of holes, and each shaft has a second end received in a respective hole of the second set of holes.

21. The combination of claim 20, wherein each of the first holes has a first diameter that is larger than a second diameter of each of the second holes and each shaft of the set of shafts has a shoulder that contacts the second vertical wall.

22. The combination of claim 20, wherein the stud receiver has a set of shaft retainers coupled to a first vertical wall of the pair of vertical walls and each shaft retainer is heat staked over an end of a respective shaft.

23. The combination of claim 1, further comprising a bracket that couples the load cell body to the first structure.

24. The combination of claim 23, wherein the bracket has a bottom portion that underlies the load cell body and at least one side portion that extends between the bottom portion and the first structure, the at least one side portion being fastened to the first structure, and the load cell body being fastened to the bottom portion.

25. The combination of claim 23, wherein the bracket comprises a bottom portion and two side portions extending upwardly from the bottom portion such that the bracket is U-shaped in cross section, the load cell body sits atop the bottom portion, and at least part of the first structure is situated above the load cell body and between the two side portions of the bracket.

26. The combination of claim 1, wherein the stud receiver is made of a plastic material and the stud is made of a metal material.

27. The combination of claim 1, wherein the first structure comprises a lift mechanism of a patient support apparatus and the second structure comprises a frame of the patient support apparatus.

28. The combination of claim 27, wherein the patient support apparatus has a length dimension defined between a head end and a foot end of the patient support apparatus and the stud has an axis that is substantially perpendicular to the length dimension of the patient support apparatus.

29. The combination of claim 27, wherein the lift mechanism is extendable and retractable to change an elevation of the frame and the load cell body is coupled to the lift mechanism so as to move upwardly and downwardly without tilting as the lift mechanism extends and retracts.

30. The combination of claim 27, wherein the lift mechanism comprises a telescoping column and a first frame member coupled to an upper region of the telescoping column, an end portion of the first frame member extends from the telescoping column toward a second frame member of the upper frame, and the load cell body is coupled to the end portion of the first frame member.

31. The combination of claim 27, wherein the upper frame comprises a frame member having a C-shaped cross section defining a channel in which the stud receiver is situated.

32. The combination of claim 31, wherein the frame member comprises a top wall, a bottom wall, and a side wall extending between the top and bottom walls and wherein the set of rollers contact an undersurface of the top wall.

33. The combination of claim 27, wherein the lift mechanism is operable to change the elevation of the frame and, as the frame changes elevation, the set of rollers roll on the frame.

34. The combination of claim 1, wherein the space of the stud receiver is defined, in part, by a pair of inclined surfaces, at least a portion of the stud is received in the hole and contacts the pair of inclined surfaces.

35. The combination of claim 34, wherein the space of the stud receiver comprises a triangular hole that is bounded, in part, by the pair of inclined surfaces.

36. The combination of claim 35, wherein corners of the triangular hole are rounded.

37. The combination of claim 1, wherein the sensor comprises at least one of following:

a strain gage, a resistive element, a capacitor, a transducer using shaped magnetic field technology, an optical sensor, a transducer that emits electromagnetic energy, a transducer that receives electromagnetic energy, or a linear variable displacement transducer.

38. The combination of claim 1, wherein the stud has a cylindrical portion.

39. The combination of claim 1, wherein the stud has a spherical portion.

40. The combination of claim 1, wherein the load cell body has a threaded hole and the stud has a threaded portion that threads into the threaded hole.