Magnetostrictive multiple position sensing device

• US 5,050,135 A
• Filed: 12/20/1989
• Issued: 09/17/1991
• Est. Priority Date: 12/20/1989
• Status: Expired due to Term

• Current Assignee: Unico, Inc.
• Original Assignee: Unico, Inc.
• Inventors: Beck, James A., Pai, Ramdas M.
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US07/453,867
• Time in Patent Office: 636 Days
• Field of Search: 324/207.24, 73/597, 73/432.1, 367/127
• US Class Current: 367/127
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/247 using time shifts of pulses
• CPC Class Codes: G01D 5/485 using magnetostrictive devices
• CPC Class Codes: G01P 15/0885 by magnetostrictive pick-up

Abstract

A position monitoring device for accurately determining a plurality of distances, velocity or acceleration along a line using a plurality of electromagnets. The position monitoring device includes an ultrasound transducer disposed along a line, an ultrasound generator to provide an ultrasound wave pulse along the ultrasound transducer and a plurality of electromagnets disposed along the line at selected positions. The electromagnets generate a magnetic field which interacts with the ultrasound pulse to generate a reflected pulse. A sensor measures the time lapse between generation of the initial pulse and receipt of the reflected pulse, and electronic components convert the time lapse interval to a position measurement.

Claims

1. A position monitoring device, comprising:

an ultrasound transducer disposed along a line;

means for generating an ultrasound interrogation pulse along said ultrasound transducer;

a plurality of electromagnets disposed along said line of said ultrasound transducer, each of said electromagnets selectively actuated for generating a magnetic field for interacting with said ultrasound interrogation pulse and causing generation of a reflected torsional strain pulse and twisting of said ultrasound transducer;

sensor means for detecting the arrival of said reflected torsional strain pulse;

means for determining a time difference interval between generation of said ultrasound interrogation wave and the arrival of said reflected torsional strain pulse; and

means for converting said time difference interval into a position measurement.

2. The position monitoring device as defined in claim 1 wherein each of said plurality of electromagnets comprises a continuously wound electromagnet attached to a mounting fixture coupled to said ultrasound transducer.

3. The position monitoring device as defined in claim 1 wherein said means for generating an ultrasound interrogation wave comprises a quartz crystal oscillator.

4. The position monitoring device as defined in claim 1 further including a mounting fixture for each of said electromagnets wherein each of said mounting fixtures includes a tapered edge portion adjacent the region of coupling to said ultrasound transducer and providing a substantially single magnetic pinch field for sensing position.

5. The position monitoring device as defined in claim 1 wherein said sensor means comprises a strain sensing means attached to said ultrasound waveguide and magnet sensing coils coupled to said strain sensing means.

6. A device for monitoring a plurality of positions along a line, comprising:

an ultrasound waveguide including a nonmagnetic waveguide housing and a conducting element;

means for generating an ultrasound interrogation pulse along said conducting element;

a plurality of electromagnets disposed along the line of said ultrasound waveguide housing and removably coupled thereto, each of said electromagnets selectively activated for generating a magnetic field for interacting with said ultrasound interrogation pulse and causing generation of a reflected torsional strain pulse and twisting of said nonmagnetic waveguide housing;

sensor means for detecting the arrival of said reflected torsional strain pulse;

means for determining a time difference interval between generation of said ultrasound interrogation wave and the arrival of said reflected torsional strain pulse; and

means for converting said time difference interval into a position measurement.

7. The device as defined in claim 6 wherein said conducting element comprises a Ni-Fe wire.

8. A position monitoring device, comprising:

an ultrasound transducer disposed along a line;

means for generating an ultrasound interrogation pulse along said ultrasound transducer;

a plurality of electromagnets disposed along said line of said ultrasound transducer, each of said electromagnets selectively actuated for generating a magnetic field for interacting with said ultrasound interrogation pulse and causing generation of a reflected torsional strain pulse and twisting a portion of said ultrasound transducer;

a plurality of electromagnets disposed along said line of said ultrasound transducer, each of said electromagnets including a continuously wound coil mounted on a coil core having a beveled single edge disposed adjacent the exterior housing of said ultrasound transducer and each of said electromagnets selectively activated for generating a magnetic field having substantially one magnetic field peak for interacting with said ultrasound interrogation pulse and causing generation of a reflected torsional strain pulse and twisting of said ultrasound transducer;

sensor means for detecting the arrival of said reflected torsional strain pulse;

means for determining a time difference interval between generation of said ultrasound interrogation wave and the arrival of said reflected torsional strain pulse; and

means for converting said time difference interval into a position measurement.

9. The position monitoring device as defined in claim 8 further including the ability to determine relative velocity of moving ones of said electromagnets.

10. The position monitoring device as defined in claim 9 wherein each of said electromagnets is independently supported for motion along said line of said ultrasound transducer.

11. The position monitoring device as defined in claim 8 wherein said ultrasound transducer comprises a flexible transducer having a variable line path selectable by the user.

12. A method for selectively monitoring and detecting desired positions of a commercial process, comprising the steps of:

positioning an ultrasound transducer along a selected line;

generating an ultrasound interrogation wave along said ultrasound transducer;

disposing a plurality of electromagnets along said line of said ultrasound transducer, activating selectively each of said electromagnets for generating a magnetic field for interacting with said ultrasound interrogation wave and causing generation of a torsional strain pulse and twisting said ultrasound transducer;

detecting the arrival of said torsional strain pulse; and

determining a time difference interval between generation of said ultrasound interrogation wave and the arrival of said torsional strain pulse.