Durakool, Inc.

Magnasphere Corporation

Larry Hedeen

Ronald J Wolf

Randall L Woods

Joseph C Hedeen

An improved magnetic switch assembly () has a housing (), a first electrode () positioned within the housing (), a second electrode (), and a magnetically movable component () located within the housing () and shiftable between a first position in simultaneous contact with electrodes (), and a second position out of such simultaneous contact. The electrode () has a radially enlarged contact section () adjacent the free end thereof which prevents hangup or sticking of component () in the first position.

Magnetic switch

A gear tooth sensor having increased sensitivity and temperature tolerance enables relatively small ferrous targets to be detected, which lends itself for use in relatively compact applications, such as the sensing of an automotive cam shaft drive wheel. All of the embodiments include a magnet having opposing north and south pole faces and a single input Hall effect IC which defines a sensing plane, and may include one or more flux concentrators. In one embodiment the sensor is configured such that the magnet is disposed adjacent the periphery of the target wheel such that the magnetic axis is generally parallel to the direction of travel of the ferrous target at an instant when the ferrous target is adjacent the magnet. In this embodiment, the Hall effect IC and flux concentrator are disposed adjacent one side of the ferrous target wheel and at least partially below the magnet. In one alternate embodiment of the invention, the magnet, Hall effect IC and flux concentrator are all aligned and disposed such that the magnetic axis is generally parallel to the direction of travel of the ferrous target at an instant when the ferrous target is adjacent the magnet. As such, the alternate embodiment is adapted to be configured relative to the ferrous target wheel for different applications. In both embodiments, additional flux concentrators can be included for adjusting the operate points of the Hall effect IC's. In yet other embodiments, the sensor is configured such that the sensing plane of the IC is generally perpendicular to the magnetic axis.

Gear tooth sensor with improved resolution and stability

An angular position sensor for sensing the angular position of a pivotally mounted device includes a magnetically sensitive device, such as a Hall effect IC, and a plurality of flux concentrators, rigidly disposed relative to the Hall effect IC, forming an assembly. The assembly is disposed in a housing a fixed distance from a rotatably mounted standard magnet defining a fixed air gap therebetween. The magnet is disposed in rotatably mounted magnet holder which also acts as a drive arm that is adapted to be mechanically coupled to a pivotally mounted device. The configuration of the flux concentrators assembled to the magnetically sensitive device cause the output of the Hall effect IC to be generally linear. In order to avoid problems associated with electrically adjustable angular position sensors, the angular position sensor in accordance with the present invention is adjusted mechanically. In particular, a flux concentrator, preferably having a halo shape, is disposed adjacent the magnet. The sensor is calibrated by varying the distance between the halo-shaped flux concentrator and the magnet. In one embodiment of the invention, the halo-shaped flux concentrator is formed to provide temperature compensation for the sensor. The sensor is hermetically sealed and is thus unaffected by wear or vibration. In an alternative embodiment, a circular magnet with a central aperture is utilized. In order to reduce the overall length of the sensor, the magnetic sensing element is disposed within the central aperture.

Mechanically adjustable linear-output angular position sensor

An angular position sensor for sensing the angular position of a pivotally mounted device includes a magnetically sensitive device, such as a Hall effect IC, and a plurality of flux concentrators, rigidly disposed relative to the Hall effect IC, forming an assembly. The assembly is disposed in a housing a fixed distance from a rotatably mounted standard magnet defining a fixed air gap therebetween. The magnet is disposed in rotatably mounted magnet holder which also acts as a drive arm that is adapted to be mechanically coupled to a pivotally mounted device. The configuration of the flux concentrators assembled to the magnetically sensitive device cause the output of the Hall effect IC to be generally linear. In order to avoid problems associated with electrically adjustable angular position sensors, the angular position sensor in accordance with the present invention is adjusted mechanically. In particular, a flux concentrator, preferably having a halo shape, is disposed adjacent the magnet. The sensor is calibrated by varying the distance between the halo-shaped flux concentrator and the magnet. In one embodiment of the invention, the halo-shaped flux concentrator is formed to provide temperature compensation for the sensor. The sensor is hermetically sealed and is thus unaffected by wear or vibration.

Contactless linear angular position sensor having an adjustable flux

A ferrous object sensor assembly is capable of sensing the presence or absence of an object of high magnetic permeability, such as a tooth or notch on a rotatably mounted ferrous wheel at zero speed and immediately upon power-up and, thus, may also be used as a proximity sensor. The ferrous object sensor assembly is comprised of a permanent magnet and a magnetic flux responsive sensor having a sensing plane which produces an electrical output signal which varies as a function of the change in magnetic flux density. The ferrous body sensor assembly does not rely upon pole face magnetism as some known conventional sensors but, rather, relies upon a the radial component of magnetic flux density emanating from a lateral surface of the magnet, intermediate opposing pole faces. Since the ferrous object sensor assembly does not rely on pole face magnetism, its electrical output signal is relatively stable over a relatively wide temperature range.

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Howe, IN, United States of America

Larry Hedeen