Multiple axis transducer mounting collar

• US 5,520,061 A
• Filed: 08/16/1993
• Issued: 05/28/1996
• Est. Priority Date: 03/14/1989
• Status: Expired due to Fees

• Current Assignee: Enprotech Corp. (New York) (Itochu Corporation)
• Original Assignee: Enprotech Corp. (New York) (Itochu Corporation)
• Inventors: Miller, William H., Brook, Warren R., Thibault, Scott E., Mannix, Timothy P.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US08/107,326
• Time in Patent Office: 1,016 Days
• Field of Search: 73/866.5, 73/620, 73/622, 73/625, 73/579, 73/628, 73/641, 73/650, 73/659, 73/660
• US Class Current: 73/866.5
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01H 1/10 of torsional vibrations
• CPC Class Codes: G01H 13/00 Measuring resonant frequency
• CPC Class Codes: G01N 2291/105 two or more emitters, two or more receivers
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/223 Supports, positioning or alignment in fixed situation mounting transducers per se G10K11/004
• CPC Class Codes: G01N 29/225 Supports, positioning or alignment in moving situation
• CPC Class Codes: G10K 11/004 Mounting transducers, e.g. provided with mechanical moving or orienting device mountings specially adapted to a particular sound-producing device, see the preceding groups G10K1/00 - G10K9/00, e.g. G10K1/26, G10K1/28, G10K9/22; arrangements of sonic watch equipment on submarines B63G8/39; buoys B63B22/00

Abstract

An improved apparatus and method for determining the existence and severity of a crack in a shaft system is provided. The apparatus includes means for mounting multiple vibration responsive output transducers around an outer circumference of the shaft system, allowing simultaneous measurements of vibrational response of the shaft system when multiple vibration responsive output transducers are mounted to the mounting means. In a first approach, the mounting means comprises a collar having two connected arcuate members, with drilled milled and tapped apertures for mounting radial input and output transducers. Torsional input and output transducers may also be mounted tangentially on the collar in drilled milled and tapped heads of bolts used to connect the two arcuate members. In a second approach, the mounting means comprises a plurality of support blocks disposed substantially symmetrically around and protruding outward from the outer collar circumference with each of the blocks orienting at least one transducer in a radial direction and at least one transducer in a tangential direction. Each block may further orient another transducer in an axial direction.

Claims

1. A collar for use in measuring vibrational response of a shaft, said collar comprising:

first and second arcuate members;

means for connecting said first arcuate member to said second arcuate member, said connected first and second arcuate members forming an outer collar circumference and having an inner circumference approximating an outer circumference of a shaft to be measured for vibrational response; and

means for mounting multiple vibration responsive transducers on said connected first and second arcuate members;

said connecting means including a bolt having two ends, at least one and being drilled, spot-faced and tapped; and

said mounting means including said at least one drilled, spot-faced and tapped end.

2. The collar of claim 1 wherein said first and second arcuate members are equal-sized and an inner circumference of each arcuate member approximates 180°

of the outer circumference of said shaft.

3. The collar of claim 1 wherein said means for connecting said first and second arcuate members comprises:

a tab angled outward at each end of said first and second arcuate members, each tab having an aperture therein for receiving a bolt; and

bolt and nut means for connecting two opposing tabs on said ends of said first and second arcuate members.

4. The collar of claim 1 wherein said means for mounting said multiple vibration responsive transducers comprises multiple drilled spot-faced tapped apertures in said connected first and second arcuate members.

5. The collar of claim 4 further comprising multiple vibration responsive transducers mounted in said apertures, each of said multiple vibration responsive transducers having a stud and each of said studs being inserted into one of said apertures.

6. The collar of claim 1 further comprising a vibration responsive transducer mounted into said one bolt end.

7. The collar of claim 6 wherein said vibration responsive transducer includes a stud, said stud being inserted into said drilled spot-faced and tapped one bolt end.

8. The collar of claim 1 further comprising means for mounting an input transducer on said connected first and second arcuate members.

9. The collar of claim 8 wherein said two ends of the bolt are drilled, spot-faced and tapped, and wherein said means for mounting said input transducer comprises at least one of said drilled, spot-faced and tapped ends of said bolt.

10. The collar of claim 9 further comprising an input transducer mounted in said drilled, spot-faced and tapped one bolt end.

11. The collar of claim 10 wherein said input transducer includes a stud, said stud being inserted into said drilled spot-faced and tapped one bolt end.

12. The collar of claim 10 wherein said input transducer comprises a tangential force input transducer.

13. The collar of claim 1 further comprising multiple vibration responsive output transducers mounted to said means for mounting multiple vibration responsive transducers.

14. The collar of claim 13 wherein at least one of said multiple vibration responsive output transducers comrpises an accelerometer.

15. The collar of claim 1, wherein both ends of said bolt are drilled, spot-faced and tapped.

16. A collar for use in measuring vibrational response of a shaft under test, said collar comprising:

a first arcuate member having two ends and a second arcuate member having two ends;

means for connecting said first arcuate member to the second arcuate member ends to ends, an inner circumference of said connected first and second arcuate members approximating an outer circumference of a shaft to be measured for vibrational response;

means for mounting multiple vibration responsive output transducers on said connected first and second arcuate members;

means for mounting an input transducer on said connected first and second arcuate members;

multiple vibration responsive output transducers mounted to said means for mounting multiple vibration responsive output transducers; and

an input transducer mounted to said means for mounting an input transducer;

said means for connecting said first and second arcuate members comprising;

a tab angled outward at each end of said first and second arcuate members, each tab having an aperture therein for receiving a bolt; and

bolts and nut means for connecting pairs of opposing tabs on said ends of said first and second arcuate members, wherein each of said bolts is premounted to one of said opposing tabs and wherein a head of each of said bolts is drilled, spot-faced, and tapped;

wherein said means for mounting said multiple vibration responsive output transducers comprises multiple drilled spot-faced tapped output apertures in said connected first and second arcuate members, and wherein said means for mounting said input transducer comprises a drilled spot-faced tapped input aperture in said connected first and second arcuate members; and

wherein each of said multiple vibration responsive output transducers has a stud and said stud is inserted into a respective one of said output apertures, and wherein said input transducer has a stud and said stud is inserted into said input aperture.

17. A collar system for use in measuring vibrational response of an axially extending shaft under test, said collar system comprising a first collar and a second collar surrounding and contiguous with a shaft under test, said second collar being axially spaced from said first collar, each of said first and second collars comprising:

a first arcuate member having two ends and a second arcuate member having two ends;

means for connecting said first and second arcuate members, wherein when said first arcuate member is connected to said second arcuate member with said connecting means, an inner circumference of said connected first and second arcuate members approximates an outer circumference of a shaft to be measured for vibrational response; and

means for mounting multiple vibration responsive output transducers on said connected first and second arcuate members.

18. The collar system of claim 17 wherein at least one of said first and second collars further comprises means for mounting an input transducer on said connected first and second arcuate members.

19. The collar system of claim 18 wherein said means for connecting said first and second arcuate members includes a bolt, said bolt having a drilled, spot-faced and tapped head, and wherein said means for mounting said input transducer comprises said drilled, spot-faced and tapped bolt head.

20. The collar system of claim 18 further comprising an input transducer mounted to said means for mounting an input transducer.

21. The collar system of claim 17 wherein said means for connecting said first and second arcuate members includes a bolt, said bolt having a drilled, spot-faced and tapped head, and wherein said means for mounting vibration responsive output transducers comprises said drilled, spot-faced and tapped bolt head.

22. The collar system of claim 17 further comprising multiple vibration responsive output transducers mounted to said means for mounting multiple vibration responsive output transducers.

23. A collar for use in measuring vibrational response of a shaft, said collar having an outer collar circumference, an inner circumference approximating an outer circumference of a shaft to be measured for vibrational response, and means for mounting multiple vibration responsive transducers, said means comprising:

first means for orienting at least one transducer in a first direction; and

second means for orienting at least one transducer in a second direction that is substantially orthogonal to said first direction.

24. The collar of claim 23 wherein said first direction is a radial direction and said second direction is a tangential direction.

25. The collar of claim 24 wherein said first and second orienting means are disposed at substantially the same radial location about said outer collar circumference.

26. The collar of claim 25 wherein said means for mounting multiple vibration responsive transducer further comprises:

third means for orienting at least one transducer in a third direction that is substantially orthogonal to both said first and said second directions, said third orienting means being disposed at substantially the same radial location about said outer collar circumference as said first and second orienting means.

27. The collar of claim 24 wherein all transducers oriented in a common direction are disposed at equal radial intervals about said outer collar circumference.

28. The collar of claim 23 wherein said means for mounting multiple vibration responsive transducers comprises:

a plurality of support means disposed substantially symmetrically around said outer collar circumference.

29. The collar of claim 28 wherein each of said support means further comprises:

third means for orienting at least one transducer in a third direction that is substantially orthogonal to both said first and said second directions.

30. The collar of claim 28 wherein each of said support means protrudes radially outward from said outer collar circumference a distance substantially greater than the radial thickness of either said first or second arcuate member.

31. The collar of claim 30 wherein each of said support means is substantially rectangular in shape and has at least two substantially planar faces, said first and second orienting means disposed one on each of said faces.

32. The collar of claim 30 wherein said first and second orienting means for each of said support means are disposed at substantially the same radial location about said outer collar circumference.

33. The collar of claim 28 comprising a radial output transducer and a tangential output transducer mounted to at least one of said support means.

34. The collar of claim 33 comprising an input transducer mounted to at least one of said support means.

35. The collar of claim 28 wherein each of said support means has a surface for mounting a radially-directed transducer slightly obliquely relative to a tangent of said outer collar circumference such that a center line drawn through the major axis of said radially-directed transducer passes through the center of said shaft.

36. The collar of claim 28 wherein said collar has substantial symmetry with respect to mass.

37. The collar of claim 36 wherein said collar has substantial symmetry with respect to stiffness.

38. The collar of claim 36 wherein said symmetry is with respect to each of a plurality of diameters through the approximate radial positions of each of said support means.

39. The collar of claim 23 wherein said collar is sufficiently rigid to substantially prevent vibrational noise caused by collar deformation or by relative motion between said collar and said shaft.

40. The collar of claim 23 comprising first and second arcuate members substantially equal-sized and wherein an inner circumference of each arcuate member approximates 180 degrees of the outer circumference of said shaft.

41. The collar of claim 23 comprising first and second arcuate members;

and

means for connecting said arcuate members comprising;

a first tapped aperture disposed on at least one end of either said first or second arcuate member; and

a connecting bolt having a threaded end sized to mate with said first tapped aperture.

42. The collar of claim 41 wherein a head of said connecting bolt has a tapped aperture for mating with a stud of a transducer.

43. The collar of claim 41 wherein the threaded end of said connecting bolt has a tapped aperture for mating with a stud of a transducer.

44. The collar of claim 41 wherein said first tapped aperture and a second tapped aperture are both disposed on opposite ends of one of said arcuate members, the other one of said arcuate members having a hole drilled fully through each of its ends, said hole being sized so that said connecting bolt passes through when said first and second arcuate members are connected.

45. The collar of claim 23 wherein said inner circumference is defined by interconnected first and second arcuate members, said inner circumference being slightly undersized relative to said outer shaft circumference so that a small gap exists between ends of said first and second arcuate members when fully connected.

46. A collar for use in measuring vibrational response of a shaft, said collar having an outer collar circumference, an inner circumference approximating an outer circumference of a shaft to be measured for vibrational response, and means for mounting multiple vibration responsive transducers thereon;

said means further comprising means for orienting at least two transducers in a tangential direction relative to said outer collar circumference.

47. The collar of claim 46 wherein said collar has substantial symmetry with respect to mass.

48. The collar of claim 46 wherein all of said transducers oriented in a tangential direction are disposed at substantially the same radial distance from the center of said shaft.

49. The collar of claim 46 wherein all of said transducers oriented in a tangential direction are disposed to be in phase.

50. A collar for use in measuring vibrational response of a shaft, said collar having an outer collar circumference, an inner circumference approximating an outer circumference of a shaft to be measured for vibration response, and means for mounting at least one vibration responsive transducer in an axial direction relative to said outer collar circumference to measure vibrational response in said axial direction, said axial direction corresponding to a longitudinal axis of said shaft.

51. The collar of claim 50, further comprising a vibration responsive transducer disposed on said mounting means.