Curvature-reduction annealing of amorphous metal alloy ribbon
AssigneeSensormatic Electronics Corporation
InventorsNen-chin Liu, Larry Speciale
Life of this patent
Estimating the term…
Abstract
A longitudinal curvature in an amorphous metal alloy ribbon is reduced by heat-treatment. While the heat-treatment occurs, the alloy ribbon is bent "backwards" against the longitudinal curvature, to reduce the amount of heat-treatment required. The process is carried out continuously by transporting the alloy ribbon from reel to reel, while wrapping the ribbon around a heated roller. Using a discrete strip cut from the alloy ribbon subjected to the curvature-reducing process, a magnetomechanical EAS marker is constructed that has a relatively low profile, while retaining desired magnetic properties.
Claims31
A method of forming magnetostrictive elements for use in a magnetomechanical electronic article surveillance marker, comprising the steps of:
- providing a continuous strip of an amorphous metal alloy;
- heat-treating the continuous amorphous alloy strip at a heating location while continuously transporting the strip past the heating location;
- applying a curvature to the continuous amorphous alloy strip, said curvature being applied by wrapping said strip around a curved element at said heating location;
- and
- cutting the heat-treated strip into discrete strips each having a predetermined length.
An apparatus for heat-treating a continuous strip of an amorphous metal alloy, comprising:
- a curved element around which the continuous amorphous alloy strip is wrapped;
- heating means for applying heat to the continuous amorphous alloy strip at the curved element;
- and
- transport means for continuously transporting the strip along a path past said heating means.
A magnetostrictive element for use in a magnetomechanical electronic article surveillance marker, formed by heat-treating a continuous strip of an amorphous metal alloy at a curved element around which the strip is wrapped, and then cutting the heat-treated continuous strip into discrete strips.
A marker for use in a magnetomechanical electronic article surveillance system, comprising a discrete amorphous magnetostrictive strip formed by heat-treating a continuous strip of an amorphous metal alloy at a curved element around which the continuous strip is wrapped and then cutting the heat-treated continuous strip.
A magnetomechanical electronic article surveillance system comprising:
- (a) generating means for generating an electromagnetic field alternating at a selected frequency in an interrogation zone, said generating means including an interrogation coil;
- (b) a marker secured to an article appointed for passage through said interrogation zone, said marker including an amorphous magnetostrictive element formed by heat-treating a continuous strip of an amorphous metal alloy at a curved element around which the strip is wrapped, and then cutting the heat-treated continuous strip into discrete strips, said marker also including a biasing element located adjacent to said magnetostrictive element, said biasing element being magnetically biased to cause said magnetostrictive element to be mechanically resonant when exposed to said alternating field;
- and
- (c) detecting means for detecting said mechanical resonance of said magnetostrictive element.
A marker for use in a magnetomechanical electronic article surveillance system, comprising a discrete amorphous strip essentially having the composition Fe.sub.40 Ni.sub.38 Mo.sub.4 B.sub.18, the marker having an overall thickness of less than 0.065 inches.
A method of reducing a degree of longitudinal curvature in an amorphous metal alloy strip having a longitudinal axis, the method comprising the steps of:
- applying a curvature to the alloy strip along the longitudinal axis of the strip and at an orientation opposite to a longitudinal curvature exhibited by the strip prior to said application of curvature, said curvature being applied by wrapping said strip around a curved element;
- and
- heat-treating the strip at the curved element.
A method of forming magnetostrictive elements for use in a magnetomechanical electronic article surveillance marker, comprising the steps of:
- providing a continuous strip of an amorphous metal alloy;
- continuously supplying the alloy strip to a heating location;
- heat-treating the alloy strip at the heating location while continuously transporting the alloy strip in a curved path at the heating location;
- and
- cutting the heat-treated strip into discrete strips each having a predetermined length.
Dependencies are inferred from the claim text.