US 3,984,707 AGranted

Spring return linear signal generator

OwnerRichard D. McClintockinventor

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Abstract

A linear signal generator, that is one operating axially as opposed to a rotating generator comprises a housing, an annular electric coil mounted about the longitudinal axis of the housing, a permanent magnet resiliently mounted for movement along the longitudinal axis of the housing through the annular coil, and means for removably latching the magnet at one end of the housing. The magnet is preferably resiliently mounted to a plunger which is depressible a sufficient amount to cause the magnet to pass into the coil and latch at the opposite end of the housing, such as by a magnetic latch. When the latching force is overcome, such as by release of the biased plunger having a biasing force in excess of the magnetic latching force, the magnet is rapidly axially propelled through the electric coil to a rest position at the opposite end of the housing where the cycle may again be repeated. The rapid passage of the magnet through the coil changes the flux of the magnetic field within the coil and causes the generation of a voltage which is proportional to the speed of movement of the magnet through the coil. The magnetic latch may comprise a magnetically permeable material, such as iron having an aperture therein which is sized to provide the maximum desirable latching force by reducing the area of the magnetically permeable material by a desired amount.

Claims5

Dependent claims

A linear signal generator comprising a housing having a longitudinal axis, an annular coil of electrically conductive material mounted about said longitudinal axis and extending in a direction along a portion thereof, a permanent magnet means resiliently mounted within said housing for repetitive axial movement along said longitudinal axis through said coil, said magnet creating a magnetic flux field, said coil being within said magnetic flux field, substantially all of the output flux of said magnet completely threading said coil, said resiliently mounted magnet comprising a permanent magnet and a compressible spring means, said generator further comprising means for moving said magnet in a first direction along said axis to compress said spring means to a loaded condition, said spring means having an associated return biasing force in said loaded condition, said housing further comprising means for latching said magnet at least substantially at one end of said annular coil with a latching force, said magnet remaining latched with said latching force until said return biasing force exceeds said latching force, said spring means thereafter propelling said magnet means through said annular electric coil toward the other end thereof, said propelled magnet producing a change in said magnetic flux field, said coil being responsive to a change in said flux field, whereby an electric current pulse is generated due to said propelled magnet movement.

Dependencies are inferred from the claim text.