Abstract: Surgical implements used during an operating procedure are detected in human tissue. Markers attached to the surgical implements change their impedance at a preselected frequency in the presence of an electromagnetic field. Each of the markers is thereby provided with signal-identifying characteristics. The signal-identifying characteristics are detected outside the operating room in an accurate, reliable manner. Potential interference with operating room electronic instrumentation is avoided, the possibility of operator error is reduced and system cost and space requirements are substantially lowered.

Abstract: Surgical implements used during an operating procedure are detected in human or animal tissue. Markers attached to the surgical implements change their impedance at a preselected frequency in the presence of an electromagnetic field. Each of the markers is thereby provided with signal-identifying characteristics. The signal-identifying characteristics are detected by a freely movable, portable detection unit from a first location proximate the patient in an accurate, reliable manner. Potential cross-interference with operating room electronic instrumentation is minimized by shielding. System cost and space requirements are substantially lowered. An accidentally retained surgical implement is discovered in a timely manner, prior to completion of surgery and before the patient has been removed from the operating room.

Abstract: Externally detectable electronic article surveillance markers are attached to surgical implements, such as sponges and surgical instruments, appointed for use in a surgical wound. The attachment mechanism facilitates detection by an external interrogating field before the wound has been closed and the patient has left the operating table. The markers are responsive to the imposition of an interrogating field produced by an electronic article surveillance system. Markers contain one or more magnetomechanically responsive elements that are urged into mechanical resonance by the interrogating field. The ring-down of the resonance and the associated dipolar electromagnetic field provide a signal-identifying characteristic detected by a detection system. Upon detection, an audible or visible signal is triggered to alert relevant medical personnel to the need for follow-up care and removal of the offending item. The resonance occurs at a frequency ranging from about 70 to 300 kHz.

Abstract: A miniature magnetic article surveillance system marker is adapted, when armed, to resonate at a frequency provided by an incident magnetic field applied within an interrogation zone. The marker comprises a magnetomechanical element having at least one elongated ductile strip of magnetostrictive ferromagnetic material disposed adjacent to a ferromagnetic element which, upon being magnetized, magnetically biases the strip and arms it to resonate at said frequency. A substantial change in effective magnetic permeability of the marker at the resonant frequency provides the marker with signal identity.

Abstract: A license plate number for any vehicle extant within a field of view of an electronic camera is interpreted as a character sequence group in an image. Each character sequence group found in the image is converted to machine readable format by an optical character recognition engine and compared with a database having a plurality of license plate numbers and associated records. Each matching license plate number and associated record is displayed within the surveillance vehicle.

Abstract: An article surveillance marker includes a marker body having two sections connected together by a resilient hinge. A securing pin holds the body sections together in a closed position and secures the marker to an article to be protected. Two ferromagnetic ribbons are housed within separate cavities in the marker body. The first ribbon is free to mechanically vibrate and produce a first signal in response to an applied interrogation field that indicates the conveyance of the protected article from an authorized area. A contact button on the marker body damps and deactivates the second ribbon when the marker body sections are closed and the marker is secured to the article. Specifically, the contact button extends through an aperture in the marker body that communicates with the cavity containing the second marker ribbon. When the marker is closed, the button engages the second ribbon and prevents mechanical vibration and, therefore, the production of a second response signal.

Abstract: A keyless entry system has means for defining an interrogation zone. A marker responsive within the interrogation zone to generate a coded signal cooperates remotely with means for disengaging a locking mechanism upon verification of the coded signal when received.

Abstract: A target adapted for use in a magnetomechanical transducer system is activated by an ac magnetic field and a variable dc bias field to produce a resonant frequency which corresponds to the effective strength of the dc bias field. The target includes an elongated ductile strip of magnetostrictive ferromagnetic material enclosed in a nonmagnetic container in a manner to allow the strip to vibrate freely. The strip has a magnetomechanical coupling factor, k greater than O, where K=zero.sqroot.(1-fr.sup.2 /fa.sup.2), fr and fa being the resonant and antiresonant frequencies, respectfully. The system is economical to construct and affords accurate and efficient measurement of pressure via displacements and angles of pressure sensitive devices at locations proximate to or remote from the signal source (target).

Abstract: A target adapted for use in a magnetomechanical transducer system is activated by an ac magnetic field and a variable dc bias field to produce a resonant frequency which corresponds to the effective strength of the dc bias field. The target includes an elongated ductile strip of magnetostrictive ferromagnetic material enclosed in a nonmagnetic container in a manner to allow the strip to vibrate freely. The strip has a magnetomechanical coupling factor, k.sub.1 greater than O, where k=(1-fr.sup.2 /fa.sup.2)1/2, fr and fa being the resonant and antiresonant frequencies, respectfully. The system is economical to construct and affords accurate and efficient measurement of displacements and angles at locations proximate to or remote from the signal source (target).

Abstract: An article control system has an encoded marker associated with an article appointed for passage through an interrogation zone. The marker resonates upon interrogation to provide a signal which is detected and compared against a code list containing at least one predefined code. A signal generated upon verification of parity between marker resonance and the predefined code triggers an alarm or actuates a gating mechanism adapted to redirect the article.

Abstract: An actuator system comprises a magnetomechanical cantilever beam adapted to be responsive to magnetic fields of various magnitudes. The system provides precise and rapid repositioning of the free end of the beam corresponding to the magnitude of the applied magnetic field. The beam is comprised of magnetostrictive ferromagnetic amorphous material and provides efficient, high force, high speed actuation to devices requiring electronically controlled variable displacement motion.

Abstract: A coplanar antenna system has an interrogating means adapted to generate time varying magnetic field components within a region proximate thereto and a receiving means adapted to detect magnetic field components within a region proximate to the antenna system. The interrogating means has a plurality of coils configured such that the components thereof have near zero net resultant magnetic field. At least one coil of the receiving means is configured to detect components thereof having a preselected net resultant magnetic field.

Abstract: An article surveillance system having an acoustic magnetomechanical marker is adapted, when armed, to resonate at a frequency provided by an incident magnetic field applied within an interrogation zone. The marker is a strip of magnetostrictive ferromagnetic material disposed adjacent to a hard magnetic element which, upon being magnetized, magnetically biases the strip and arms it to mechanically vibrate at said frequency. A substantial change in acoustic output level of the marker at the resonant frequency provides the marker with signal identity.

Abstract: A magnetic theft detection system marker is adapted to generate magnetic fields at frequencies that (1) are harmonically related to an incident magnetic field applied within an interrogation zone and (2) have selected tones that provide the marker with signal identity. The marker is an elongated, ductile strip of amorphous ferromagnetic material having a value of magnetostriction near zero that retains its signal identity under stress.

Abstract: A magnetic article surveillance system marker is adapted, when armed, to resonate at preselected frequencies provided by an incident magnetic field applied within an interrogation zone. The marker is a plurality of elongated ductile strips of magnetostrictive ferromagnetic material each of the strips being disposed adjacent to a ferromagnetic element which, upon being magnetized, magnetically biases the strips and arms them to resonate at the preselected frequencies. A substantial change in effective magnetic permeability of the marker at the preselected frequencies provides the marker with signal identity.

Abstract: A magnetic article surveillance system marker is adapted, when armed, to resonate at a frequency provided by an incident magnetic field applied within an interrogation zone. The marker is an elongated ductile strip of magnetostrictive ferromagnetic material disposed adjacent to a ferromagnetic element which, upon being magnetized, magnetically biases the strip and arms it to resonate at said frequency. A substantial change in effective magnetic permeability of the marker at the resonant frequency provides the marker with signal identity.

Abstract: This invention provides a vibration sensor for detecting vibrations having preselected frequencies. The sensor has a plurality of tuning mechanisms each being mechanically resonant with a different preselected vibrational frequency. The resonating vibrational movements of these tuning mechanisms apply varying stresses to a plurality of glassy magnetostrictive elements associated therewith. Each of the magnetostrictive elements is responsive to a different one of the tuning mechanisms. A magnetic biasing element imparts a magnetization to the magnetostrictive elements and a detecting mechanism associated with the magnetostrictive elements detects changes in the magnetization thereof caused by the varying stresses applied thereto.

Abstract: This invention comprises a vibration sensor for detecting engine knock. The sensor has a tuning mechanism which is mechanically resonant with a preselected vibrational frequency. The resonating movements of this tuning mechanism are adapted to apply varying stress to an associated magnetostrictive element. A magnetic biasing element imparts a magnetization to the magnetostrictive element and a detecting means is associated with the magnetostrictive element for detecting changes in the magnetization caused by the varying applied stress.

Abstract: A temperature-sensitive switch is provided with a resilient movable cantilever composed of amorphous ferromagnetic material having a Curie point. The cantilever is adapted to carry a first contact member. A second contact member is disposed adjacent the first contact member for at least intermittently establishing electrical contact with the first contact member. A magnet is associated with and adapted to bias the cantilever to a first position that establishes electrical continuity between the first and second contact members. The cantilever is transformed from a ferromagnetic phase to a paramagnetic phase when its temperature exceeds the Curie point, whereby the cantilever assumes a second position in which the electrical conductivity is interrupted. The switch is lightweight, compact, economical to manufacture and reliable in operation.

Abstract: A magnetic theft detection system marker is adapted to generate magnetic fields at frequencies that (1) are harmonically related to an incident magnetic field applied within an interrogation zone and (2) have selected tones that provide the marker with signal identity. The marker is an elongated, ductile strip of amorphous ferromagnetic material having a value of magnetostriction near zero that retains its signal identity under stress.