Abstract: A deactivatable electronic theft detection marker is made from a strip or ribbon of high magnetic permeability strip or ribbon and then high magnetic coercivity material is deposited on the strip or ribbon by electroplating.

Abstract: An electronic article surveillance system responder which comprises an electrical responder circuit and a housing which mounts the circuit on an article to be protected. The housing is arranged to support the circuit in such a manner that a dielectric region is formed between the circuit and the article. An electrically conductive plate is also held by the housing on the opposite side of the dielectric region from the circuit to isolate the circuit from the effects of metal objects on which the responder is mounted. The housing is flared so that it can be mounted on an article in proper orientation.

Abstract: An electronic theft detection system with a transmitter antenna assembly which includes a flat electrically conductive panel positioned close to a transmitter loop antenna to preload it and isolate it from the loading effects of nearby metal objects and a receiver arranged with a signal gate synchronized to the transmitter antenna energization to prevent detection of targets located on the opposite side of the panel from the transmitter loop antenna.

Abstract: A fastener and fastener assembly characterized by a pin with an expansive molded plastic head of concave configuration and a frangible membrane sealed to the head to enclose a hollow space for containing an undesirable fluid such as a dye, so that when prying forces are applied to bend the head, the membrane is stressed and shatters to release the dye.

Abstract: A magnetically releasable pin lock which comprises catch elements mounted to pivot about axes perpendicular to and displaced from the pin axis and elongated magnetizable actuation elements which extend from the catch elements along the pin axis to be acted upon by applied magnetic decoupling fields and to move in response to such fields to pivot the catch elements and release the pin.

Abstract: An article surveillance system includes a first monitor 26 at a store exit way 12 and second monitors 34 in the dressing rooms 20 and rest rooms 22 in the store to detect security tags 24 attached to articles of merchandise 14. When the tags 24 are attached to the merchandise they hold a ring 82 against the tags causing them to have a high resonant frequency which is detected by the first monitors 26 but not the second monitors 34. If the tags are removed from the merchandise in a dressing room or rest room, the ring falls away from the tag and its resonant frequency lowers and the tag is then detected by the second monitor 34.

Abstract: A deactivator for deactivating targets used in electromagnetic article surveillance systems comprises a solid element with a convexly curved outer surface, e.g., a cylinder and a plurality of permanent magnets which form a patter of variously directed magnetic fields is a plane adjacent the surface. The curved surface of the deactivator is rolled over a target to be deactivated. The magnets are also arranged in adjacent layers with the magnets of one layer extending in a different direction from the magnets of the other layer to form a composite magnetic pattern which is discontinuous in all directions.

Abstract: A fastening assembly for fastening a wafer (10) to an article of merchandise (12) and comprising a locking mechanism in a housing (14) and a fastener element (16) having an expansive head (18) and a shank (20), formed with axially spaced circumferential grooves 22 for releasable locking engagement with a locking mechanism, the head having a conical exterior with an apex angle less than ninety degrees so that if the fastener element should fall onto a flat surface, the shank will slant upwardly less than forty five degrees; and downward pressure on the tip of the shank will cause it to tilt downwardly safely and without appreciable resistance.

Abstract: A fastening means for fastening a wafer to an article of merchandise and comprising a tack-like element whose shank passes through the merchandise and the wafer and a button-like fastening element which securely holds the shank of the tack-like element. The head of the tack-like element is freely rotated and tiltable on the shank to resist unauthorized efforts to release the fastening means.

Abstract: An electronic monitoring system for monitoring the passage of objects, such as persons, past a monitoring station. An antenna is provided flat on the floor of the station to generate electromagnetic fields in the vicinity of the station and to generate electrical alarm signals whenever the electromagnetic fields are disturbed by the passage of an object carrying a special responder device. The responder device comprises an elongated bar of ferromagnetic material about which is wound the coil of a resonant electrical circuit. A mounting strap is provided to mount a responder device the leg of each object to be monitored such that the elongated bar is held perpendicular to the floor whereby maximum electrical interaction is provided between the antenna and the resonant electrical circuit.

Abstract: Magnetic detection means for protection of articles such as books, records and the like, wherein a target, of magnetically soft or easily saturable magnetic material, such as permalloy foil, is mounted on the protected article and emits magnetic signals which are harmonics of an interrogating magnetic field generated at an exit station. The target is curved along its length and provides good signal response over a wide range of orientation.

Abstract: An electromagnetic interrogation field in a theft detection system is made effectively more uniform by energizing different antenna windings lying in different planes at the same frequency but at different phases so that the resulting field pattern rotates in the vicinity of the antenna windings.