US 5,479,099 AGranted

Magnetic inspection head suited for contoured or irregular surfaces

AssigneeIowa State University Research Foundation, Inc.

InventorsDavid C. Jiles, David A. Kaminski

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Abstract

A magnetic inspection head adapted for use with samples having non-planar surfaces. A magnetically permeable core has a pair of poles joined by a magnetically permeable bridge to form a closed magnetic circuit between the pole legs, bridge and the test material. Each pole has magnetically permeable support means terminating in a magnetically permeable deformable surface for engaging the sample. The support means is yieldable such that when the inspection head is placed in contact with the irregular surface of the sample, the deformable surface is deformed to accommodate the shape of the sample with minimal air gaps therebetween. Preferably, the deformable surface is provided by a plurality of pins slidably engaged in a pole structure and urged outwardly for contact with and conformance with a non-planar sample surface.

Claims16

Dependent claims

A magnetic inspection head for measuring magnetic properties of a sample having a non-planar surface, the magnetic inspection head comprising, in combination:

a magnetically permeable core having two arrays of apertures covering substantially similar areas joined by a bridge;
a plurality of magnetically permeable pins in the apertures mounted with their distal ends projecting through the core to form a contact surface, the pins being slidable in the apertures so that they can project by differing amounts through the core;
pin loading means for urging the distal ends of the pins outwardly from the core so that the distal ends of the pins substantially conform to the non-planar surface of the sample with minimal air gaps when the inspection head is disposed on the sample;
power coils associated with the arrays of pins to induce a magnetic field in a magnetic circuit including the arrays of pins, the bridge, and the sample;
a power supply for producing drive currents at controllable levels in the power coils for producing magnetic fields of respectively controllable levels;
and
flux coil means in the magnetic circuit adapted to measure the response of the sample to the field induced by the power coils.

4 more elements

A magnetic inspection head for measuring magnetic properties of a sample having a non-planar surface, the magnetic inspection head comprising, in combination:

a magnetically permeable core having two poles joined by a bridge, each pole having magnetically permeable support means terminating in a magnetically permeable deformable surface for engaging the sample, the support means being yieldable such that when the inspection head is placed in contact with the non-planar surface of a sample, the deformable surfaces deform to accommodate the shape of the sample surface with minimal air gaps therebetween;
power coil means on the core for inducing a magnetic field in a magnetic circuit which includes the core and sample;
a power supply for producing drive currents at controllable levels in the power coils for producing magnetic fields of respectively controllable levels;
and
flux coil means on the core for measuring the magnetic flux passing through the circuit as the response of the sample to the field induced by the power coil means.

2 more elements

Dependencies are inferred from the claim text.