Screening apparatus for imparting multimodal and multi-axial vibrations to a device

• US 5,412,991 A
• Filed: 07/23/1993
• Issued: 05/09/1995
• Est. Priority Date: 03/01/1990
• Status: Expired due to Fees

• Current Assignee: US Bank National Association (US Bancorp)
• Original Assignee: Qualmark Corporation (Espec Corporation)
• Inventors: Hobbs, Gregg K.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Finley, Rose M.
• Application Number:
  US08/097,282
• Time in Patent Office: 655 Days
• Field of Search: 73/662, 73/663, 73/667, 73/668
• US Class Current: 73/663
• CPC Class Codes: F16B 2200/403 Threaded clamping parts
• CPC Class Codes: F16B 2200/73 Cam locks or thread locks
• CPC Class Codes: G01M 7/06 Multidirectional test stands

Abstract

A shaker table (10) for testing and quality control of devices attached to the table is shown. The mounting table has pneumatic exciters (50) attached thereto. The mounting table (20) provides uniform distribution of forces applied by the pneumatic exciters (50). The forces are evenly distributed in all directions from the impact of the exciters on the mounting table. The mounting table (20) is supported on a foundation (2) by adjustable supports (4). The exciters are supplied with pressurized air from a source (12) through an airline (14).

Claims

1. Vibration screening apparatus for imparting multimodal and multi-axial vibrations to a device to be screened, comprising:

mounting table means for supporting said device, for converting stress waves from impact forces into multimodal and multi-axial vibrations, and for transmitting said multimodal and multi-axial vibrations to said device, said mounting table means including a rigid core structure fabricated with material that has a length, width, and thickness, which material has a plurality of abrupt discontinuities in thickness;

impact actuator means connected to said mounting table means for imparting sequential impact forces to said rigid core structure; and

mounting means on said mounting table means for mounting said device securely on said mounting table means in substantially immoveable relation to said rigid core structure.

2. The vibration screening apparatus of claim 1, wherein said core structure comprises a slab of rigid material that has a substantially flat upper surface and a bottom surface with a plurality of cavities recessed in spaced apart relation to each other into the bottom surface to extend partially through the thickness of the core structure toward the top surface and with portions of the material of the material between said cavities forming partition walls between said cavities.

3. The vibration screening apparatus of claim 2, wherein said slab of rigid material has abrupt discontinuities in said thickness at intersections of said cavities with said partition walls.

4. The vibration screening apparatus of claim 3, wherein said impact actuator means is connected to said mounting table means at one of said partition walls and imparts said impact forces to said core structure at that partition wall.

5. The vibration screening apparatus of claim 4, wherein said impact actuator means includes a pneumatic hammer.

6. The vibration screening apparatus of claim 4, wherein the partition wall to which said impact actuator means is connected is wider and has more of the slab of rigid material between adjacent cavities than other ones of the partition walls.

7. The vibration screening apparatus of claim 4, including a plurality of impact actuator means connected respectively to a plurality of said partitions for imparting impact forces to said plurality of partition walls.

8. The vibration screening apparatus of claim 3, wherein said cavities extend through more than one-half of said thickness of said core structure.

9. The vibration screening apparatus of claim 8, wherein said cavities extend through more than three-fourths of said thickness of said core structure.

10. The vibration screening apparatus of claim 9, wherein said cavities leave a remaining material thickness between said cavities and said substantially flat upper surface, and wherein said partition walls have a width that extends between adjacent cavities, and wherein said partition wall width between said cavities is greater than said remaining material thickness between said cavities.

11. The vibration screening apparatus of claim 2, wherein said partition walls have distal ends that widen into flanges at the bottom surface.

12. The vibration screening apparatus of claim 2, including a rigid skin sheet affixed to said bottom surface substantially enclosing said cavities.

13. The vibration screening apparatus of claim 12, wherein said rigid material is metal.

14. The vibration screening apparatus of claim 13, wherein said rigid material comprises aluminum.

15. The vibration screening apparatus of claim 12, wherein said skin sheet is metal.

16. The vibration screening apparatus of claim 15, wherein said skin sheet comprises aluminum.

17. The vibration screening apparatus of claim 12, including a film of adhesive material interposed between said bottom surface and said skin sheet.

18. The vibration screening apparatus of claim 12, including a rubber mounting sheet positioned over said upper surface.

19. The vibration screening apparatus of claim 13, including an insulating layer interposed between said upper surface and said rubber mounting sheet.

20. The vibration screening apparatus of claim 2, wherein said core structure has a threaded hole extending into said upper surface in alignment with one of said partition walls, and said mounting means comprises said threaded hole in combination with a threaded shank or bolt.

21. The vibration screening apparatus of claim 20, wherein said core structure has a plurality of threaded holes extending into said upper surface in alignment with a plurality of said partition walls.

22. The vibration screening apparatus of claim 6, wherein said core structure has a threaded hole extending into said bottom surface in alignment with said wider partition wall, and wherein impact actuator means is connected to said mounting table means with a threaded shank or bolt screwed into said threaded hole.

23. The vibration screening apparatus of claim 2, wherein said cavities are arrayed in rows and columns across said core structure forming said partition walls in a grid pattern of intersecting partition walls surrounding said cavities.

24. The vibration screening apparatus of claim 23, wherein said core structure has a actuator mounting hole extending from said bottom surface into said slab of rigid material in alignment with a location where said partition walls intersect, and wherein said impact actuator means is connected to said mounting table means with a shank or bolt inserted into said actuator mounting hole.

25. The vibration screening apparatus of claim 24, wherein said core structure has a device mounting hole extending from said upper surface into said slab of rigid material in alignment with a location where said partition walls intersect, and wherein said mounting means includes said device mounting hole.

26. The vibration screening apparatus of claim 25, wherein said core structure has a plurality of actuator mounting holes extending from said bottom surface into said slab of rigid material in alignment with a plurality of respective locations where said partition walls intersect, and wherein said impact actuator means includes a plurality of pneumatic hammers connected to said mounting table means with a plurality of shanks or bolts inserted into said actuator mounting holes.

27. The vibration screening apparatus of claim 26, wherein said core structure has a plurality of device mounting holes extending from said upper surface into said slab of rigid material in alignment with a plurality of locations where said partition walls intersect, and wherein said mounting means includes said device mounting holes.

28. The vibration screening apparatus of claim 27, wherein said actuator mounting holes extend in said core structure in alignment with different intersections of said partition walls than the intersections of partition walls with which said device mounting holes are aligned.

29. The vibration screening apparatus of claim 28, wherein the slab material at the intersections of partition walls aligned with said actuator mounting holes is wider than the slab material at the intersections of partition walls aligned with said device mounting holes.

30. The vibration screening apparatus of claim 29, including a rigid skin sheet affixed to said bottom surface substantially enclosing said cavities and having holes therethrough aligned with said actuator mounting holes.

31. The vibration screening apparatus of claim 30, wherein said rigid material is metal.

32. The vibration screening apparatus of claim 31, wherein said rigid material comprises aluminum.

33. The vibration screening apparatus of claim 30, wherein said skin sheet is metal.

34. The vibration screening apparatus of claim 33, wherein said skin sheet comprises aluminum.

35. The vibration screening apparatus of claim 30, including a film of adhesive material interposed between said bottom surface and said skin sheet.

36. The vibration screening apparatus of claim 29, including a rubber mounting sheet positioned over said upper surface and having holes therethrough aligned with said device mounting holes.

37. The vibration screening apparatus of claim 36, include an insulating layer interposed between said upper surfaces and said rubber mounting sheet.

38. Vibration screening apparatus for imparting vibrations to a device to be screened, comprising:

a rigid core structure having a top surface and a bottom surface;

a layer of insulation material that is less heat conductive than said core structure laminated over said top surface of said core structure;

mounting means for releasably attaching said device in substantially immovable relation to said core structure with said layer of insulation material interposed between said core structure and said device; and

actuator means connected to said core structure adjacent said bottom surface for inducing vibrational stress waves in said core structure.

39. The vibration screening apparatus of claim 38, including a resilient, elastomeric layer laminated over said layer of insulation.

40. The vibration screening apparatus of claim 38, including a second layer of insulation material that is less heat conductive than said core structure interposed between said core structure and said actuator means.

41. The vibration screening apparatus of claim 40, wherein said second layer of insulation material comprises titanium.