PULSE GENERATOR

• US 3,742,243 A
• Filed: 09/27/1971
• Issued: 06/26/1973
• Est. Priority Date: 09/27/1971
• Status: Expired due to Term

• Current Assignee: John G. Gamble
• Original Assignee: John G. Gamble
• Inventors: Gamble, John G.
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Smith, William J.
• Application Number:
  US05/183,945
• Time in Patent Office: 638 Days
• Field of Search: 73/518,519,DIG.3 324/70 307/106 324/168,171,174 335/56,92,97
• US Class Current: 307/106
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01F 15/063 using electrical means

Abstract

A rotary pulse generator having a magnetic readout head with a Hall sensor and a rotor cooperable with the readout head for applying an alternating magnetic field to the Hall sensor for producing an electrical signal for each predetermined increment of angular displacement of the rotor. In one version the rotor comprises a pair of spaced coaxial magnet rings providing in an axial gap therebetween an annular alternating magnetic field to be applied to the Hall sensor as the rotor rotates. In other versions, the magnetic readout head employs a bistable magnetic shunt which cooperates with equiangularly spaced teeth or poles of the rotor for applying an alternating magnetic field to the Hall sensor as the rotor rotates.

Claims

1. A pulse generator responsive to relative displacement along a predetermined path comprising magnetic field generator means having a first plurality of ferromagnetic poles along said predetermined path and a magnet pickup with a Hall sensor and operable upon the application of a magnetic field to the hHall sensor to generate an electrical signal, the Hall sensor and first plurality of ferromagnetic poles being mounted for relative movement along said predetermined path, the magnetic field generator means further comprising bistable magnetic circuit means associated with the Hall sensor adapted to be selectively magnetically switched to each of two alternative stable magnetic states respectively having substantially oppositely directed magnetic fields applied to the Hall sensor and operable by the ferromagnetic poles upon relative displacement of the Hall sensor and the ferromagnetic poles along said predetermined path to be switched back and forth between its two alternative stable magnetic states to apply an alternating magnetic field to the Hall sensor to operate the magnetic pickup to generate a train of electrical signals in accordance with such relative displacement.

2. A pulse generator according to claim 1 wherein the ferromagnetic poles are substantially equally spaced along said predetermined path and such that an electrical signal is produced for substantially each predetermined increment of relative displacement of the Hall sensor and the ferromagnetic poles along said predetermined path.

3. A pulse generator according to claim 1 wherein the magnetic field generator means comprises a rotor having said first plurality of ferromagnetic poles in an annular arrangement thereon for movement relative to the Hall sensor.

4. A pulse generator according to claim 3 wherein the rotor comprises an annular permanent magnet axially magnetized to provide opposite poles on opposite axial ends thereof and pole plates on opposite axial ends of the circular magnet having said first plurality of ferromagnetic poles.

5. A pulse generator according to claim 4 wherein the pole plates have the same number of equiangularly spaced poles.

6. A pulse generator according to claim 5 wherein the poles of the pole plates are angularly offset such that the poles of each plate are substantially midway between adjacent poles of the other plate.

7. A pulse generator according to claim 1 wherein the bistable magnetic circuit means comprises a bistable ferromagnetic shunt associated with the Hall sensor having a second plurality of ferromagnetic poles along said predetermined path cooperable with said first plurality of ferromagnetic poles to be magnetically switched back and forth between said two alternative stable magnetic states to apply said alternating magnetic field to the Hall sensor upon relative displacement of the first and second ferromagnetic poles along said predetermined path.

8. A pulse generator according to claim 7 wherein the ferromagnetic shunt is generally E-shaped with a center leg associated with the Hall sensor and a pair of outer legs, the center and outer legs having said second plurality of ferromagnetic poles cooperable with said first plurality of ferromagnetic poles to magnetically switch the shunt back and forth between said two alternative stable magnetic states to apply said alternating magnetic field through the center leg to the Hall sensor.

9. A pulse generator according to claim 7 wherein the bistable magnetic circuit means further comprises magnet means mounted in spaced relationship with said second plurality of ferromagnetic poles of the ferromagnetic shunt and such that the first plurality of ferromagnetic poles pass therebetween to magnetically switch the shunt back and forth between said two alternative stable magnetic states to produce an alternating magnetic field in the ferromagnetic shunt.

10. A pulse generator according to claim 9 wherein said magnet means comprises a third plurality of ferromagnetic poles in spaced relationship with said second plurality of ferromagnetic poles respectively such that the first plurality of ferromagnetic poles pass therebetween to magnetically switch the shunt back and forth between its said alternative stable magnetic states to produce an alternating magnetic field in the ferromagnetic shunt.

11. A rotary electrical pulse generator comprising a rotor with a pair of coaxial permanent magnet rings having an annular air gap between the inner axial sides thereof, each magnet ring having an annular arrangement of a plurality of contiguous axially extending and axially inwardly pointing generally U-shaped magnetic circuits, the adjacent U-shaped magnetic circuits of each magnet ring having contiguous poles of like polarity forming a joint magnetic pole of higher magnetic intensity and the U-shaped magnetic circuits of each magnet ring providing an even plurality of substantially equiangularly spaced joint magnetic poles of alternating magnetic polarity on the inner axial side thereof, the pair of coaxial magnet rings having their respective joint magnetic poles in substantially axially aligned magnetic attraction whereby an annular arrangement of a plurality of generally oval contiguous magnetic circuits is formed by the pair of coaxial magnet rings to produce an annular alternating magnetic field in the annular air gap therebetween having axially extending magnetic fields between the joint poles and sharp magnetic field reversal, and magnetically responsive pickup means mounted in the annular air gap between the magnet rings to be acted upon by the alternating magnetic field to generate substantially equally spaced electrical signals as the rotor rotates.

12. A pulse generator according to claim 11, wherein the magnet rings are annular permanent magnets each magnetized to form said U-shaped magnetic circuits.

13. A pulse generator according to claim 11 wherein each magnet ring comprises a ferromagnetic ring with a plurality of angularly spaced axially extending ferromagnetic pole pieces and permanent magnet segments between the ferromagnetic pole pieces having axially extending magnetic axes generally parallel to the ferromagnetic pole pieces such that the permanent magnet segments and ferromagnetic ring of each magnet ring together form its said U-shaped magnetic circuits.

14. A pulse generator according to claim 11 wherein the pickup means comprises a plurality of substantially equiangularly spaced magnetically responsive pickups along a portion of said annular air gap no greater than the spacing between joint adjacent magnetic poles of like polarity.