Tunable magnetic device for use in a proximity sensor
AssigneePhoenix America, Inc.
InventorJohn M. Kaste
Life of this patent
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Abstract
A tunable magnetic device which includes a permanent magnet in the shape of a ring, an inner aperture, a tuning member, and a field sensor secured to the permanent magnet. The tuning member may be a ferrous or magnetic material and may be secured to a non-magnetic tuning device. The inner aperture is preferably small compared to the permanent magnet. The magnetic device provides a magnetic field that is sensitive to the proximity of a ferrous object and provides a tunable mechanism to locally balance the magnetic field where the field sensor is located.
Claims18
A tunable magnetic device comprising:
- a magnet structure comprising a permanent magnet and a ferrous tuning element operably associated with said magnet, said magnet structure lacking pole pieces;
- and
- a magnetic field sensor secured to said magnet structure in proximity to said ferrous tuning element.
A tunable magnetic device comprising:
- a magnet structure comprising a permanent magnet and an inner magnet operably associated with said permanent magnet, said magnet structure having no pole pieces;
- and
- a magnetic field sensor secured to said permanent magnet and located closely adjacent said inner magnet, the magnetization of said inner magnet adjustable to provide tuning for said tunable magnetic device.
A tunable magnetic device comprising:
- a magnet structure including a single disc of permanent magnet material magnetized with concentric poles, said magnet structure having no pole pieces;
- and
- a magnetic field sensor bonded to said disc.
Dependencies are inferred from the claim text.