Integral magnet vibration sensor

• US 6,598,479 B1
• Filed: 11/19/2001
• Issued: 07/29/2003
• Est. Priority Date: 11/19/2001
• Status: Active Grant

• Current Assignee: Computational Systems Incorporated (Emerson Electric Company)
• Original Assignee: CSI Technology Incorporated (Emerson Electric Company)
• Inventors: Robinson, James C., Piety, Kenneth R., Pardue, Bradley D.
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/988,926
• Time in Patent Office: 617 Days
• Field of Search: 736/49, 736/58, 736/60, 735/70, 735/93, 734/31, 738/665
• US Class Current: 73/658
• CPC Class Codes: G01H 11/06 by electric means

Abstract

An integral magnet vibration sensor apparatus optimizes sensor response in a non-permanently attachable package. In a preferred embodiment of the invention, the apparatus includes a housing having a magnet, a vibration sensor, and a conditioning circuit disposed within the housing. The magnet enables the apparatus to be magnetically attached to a machine. The vibration sensor senses machine vibration when the apparatus is attached to the machine, and the conditioning circuit optimizes the frequency response of the vibration sensor in a preferred embodiment by reducing the gain of the sensor output at resonance.

Claims

1. A vibration sensing apparatus for being attached to a machine, the apparatus having a resonant frequency, said apparatus comprising:

a housing having a first end and a second end;

a magnet disposed within said housing adjacent the first end and rigidly affixed thereto for magnetically attaching the apparatus to the machine;

a vibration sensor disposed within said housing adjacent said magnet for sensing vibration produced by the machine and producing a sensor signal in the form of an electrical charge corresponding to sensed vibration, said vibration sensor being in rigid relation to said magnet and electrically isolated therefrom;

a conditioning circuit associated with said housing for conditioning the sensor signal and producing a conditioned sensor signal, said conditioning circuit including;

a filter for receiving the sensor signal and attenuating the sensor signal at the resonant frequency of the apparatus, producing a filtered sensor signal in the form of an electrical charge; and

a converter for converting the filtered sensor signal from an electrical charge to an electrical voltage for use by a peripheral device; and

an output port adjacent the second end of the housing for outputting the conditioned sensor signal to the peripheral device.

2. The apparatus of claim 1, further comprising a plurality of feet rigidly attached to the first end of said housing for contacting a machine surface when the apparatus is magnetically attached to the machine.

3. The apparatus of claim 1 wherein said output port includes a threaded connector to facilitate attachment of the apparatus to the peripheral device.

4. The apparatus of claim 1 wherein said filter is a two-pole, low-pass filter.

5. The apparatus of claim 1 wherein said vibration sensor is a single axis sensor.

6. The apparatus of claim 1 wherein said vibration sensor is a multiple axis sensor.

7. A vibration sensing apparatus for being attached to a machine, the apparatus having a resonant frequency, said apparatus comprising:

a housing having a first end and a second end;

a magnet disposed within said housing adjacent the first end and rigidly affixed thereto for magnetically attaching the apparatus to the machine;

a vibration sensor disposed within said housing adjacent said magnet for sensing vibration produced by the machine and producing a sensor signal corresponding to sensed vibration, said vibration sensor being in rigid relation to said magnet and electrically isolated therefrom;

a conditioning circuit disposed within said housing for conditioning the sensor signal, producing a conditioned sensor signal;

a plurality of feet rigidly attached to the first end of said housing for contacting a machine surface when the apparatus is magnetically attached to the machine, said plurality of feet inhibiting movement of the apparatus relative to the machine when the apparatus is attached to an uneven portion of the machine; and

an output port adjacent the second end of the housing for outputting the conditioned sensor signal to a peripheral device.

8. The apparatus of claim 7 wherein said sensor signal is in the form of an electrical charge and said conditioning circuit includes:

a filter for receiving the sensor signal and attenuating the sensor signal at the resonant frequency of the apparatus, producing a filtered sensor signal in the form of an electrical charge; and

a converter for converting the filtered sensor signal from an electrical charge to an electrical voltage for use by the peripheral device.

9. The apparatus of claim 8 wherein said filter is a two-pole, low-pass filter.

10. The apparatus of claim 7 wherein said output port includes a threaded connector to facilitate attachment of the apparatus to the peripheral device.

11. The apparatus of claim 7 wherein said vibration sensor is a single axis sensor.

12. The apparatus of claim 7 wherein said vibration sensor is a multiple axis sensor.

13. The apparatus of claim 7 wherein said magnet is a permanent magnet.

14. A vibration sensing apparatus for being attached to a machine, the apparatus having a resonant frequency, said apparatus comprising:

a housing having a first end and a second end;

a magnet disposed within said housing adjacent the first end and rigidly affixed thereto for magnetically attaching the apparatus to the machine;

a vibration sensor disposed within said housing adjacent said magnet for sensing vibration produced by the machine and producing a sensor signal corresponding to sensed vibration, said sensor signal including a substantially linear response range where the sensor signal varies by no more than ±

3 dB over a bandwidth of frequencies up to 10 KHz, said vibration sensor being in rigid relation to said magnet and electrically isolated therefrom;

a conditioning circuit disposed within said housing for conditioning the sensor signal, producing a conditioned sensor signal; and

an output port adjacent the second end of the housing for outputting the conditioned sensor signal to a peripheral device.

15. The apparatus of claim 14 wherein said response at the resonant frequency is no more than 15 dB relative to the vibration sensor response in said substantially linear response range.

16. A vibration sensing apparatus for being attached to a machine, the apparatus having a resonant frequency, said apparatus comprising:

a housing having a first end and a second end;

a magnet disposed within said housing adjacent the first end and rigidly affixed thereto for magnetically attaching the apparatus to the machine;

a vibration sensor disposed within said housing adjacent said magnet for sensing vibration produced by the machine and producing a sensor signal corresponding to sensed vibration, said sensor signal including a substantially linear response range, said vibration sensor being in rigid relation to said magnet and electrically isolated therefrom;

a conditioning circuit associated with said housing for attenuating the sensor signal at resonance to a level of no more than 15 db relative to the vibration sensor response in said substantially linear response range, producing an attenuated sensor signal; and

a connector adjacent the second end of the housing for outputting the attenuated sensor signal to a peripheral device.