Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-05-24
2001-09-04
Trieu, Van T. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S426110, C340S572800
Reexamination Certificate
active
06285286
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an anti-theft device for deterring theft of a protected article, the device comprising first and second housing elements and a locking mechanism for securing a male portion of the second housing element to a female portion of the first housing element, the locking mechanism being arranged to release the male portion from the female portion, when actuated by an unlocking device operated by an authorized person.
DESCRIPTION OF THE PRIOR ART
Anti-theft devices of the kind described above are used for deterring theft of protected articles or goods, especially in shops or stores. It is of particular interest for the owner of a shop to protect attractive and easily removable articles, such as clothes, handbags, shoes, etc, by attaching an anti-theft device to each article. The attachment is made in such a manner, that the anti-theft device can only be removed from the protected article by means of a dedicated unlocking device, which only authorized persons have access to. The anti-theft device is often provided with at least one glass ampoule containing a discoloring or ill-smelling fluid. Furthermore, the anti-theft device is designed in a way, so that the glass ampoule will break and start leaking, if an unauthorized person, such as a thief, tampers with the anti-theft device in an attempt to remove the device from the protected article. Hence, since the broken glass ampoule will immediately stain or contaminate the article and make it useless for all practical purposes, a potential thief is discouraged from such a tampering attempt.
As an alternative to the fluid-containing ampoule(s), the anti-theft device may be provided with sensor or transponder means detectable by an electronic article surveillance system (EAS). The anti-theft device may for instance be provided with a thin metal strip of an amorphous magnetic alloy. The magnetic properties of the metal strip are controllable by means of an alternating magnetic field generated by external means, such as inductive detection arcs. Such transponders or sensors are for instance disclosed in U.S. Pat. No. 5,469,140, U.S. Pat. No. 5,414,412, U.S. Pat. No. 5,406,262 and WO97/29463.
U.S. Pat. No. 5,275,122 discloses an anti-theft device as described above, which is intended to be attached to an attractive article for the protection thereof. The device comprises a first element with a connecting pin to be inserted through the article, and a second element, which is intended for attachment to the connecting pin. The first element includes a fragile ampoule containing a staining liquid, said ampoule breaking upon manipulation of the anti-theft device. The first element acts as a device base element, while the second element acts as a locking element or head, which is mounted on the pin of the base element so as to firmly secure the protected article between the first and the second elements. For this purpose the head comprises a locking device, which is designed so that the head may easily be moved along the axial direction of the pin in one direction only, namely towards the base element, whereas any attempt to move the head in the opposite direction, i.e. away from the base element, will cause the head to be immediately locked to the pin.
The locking mechanism in the head includes a number of small metallic retaining balls, which are disposed in internal grooves in the head, in a way so that the retaining balls are firmly clamped against the pin and the bottom of the grooves, when the head is drawn outwards, while allowing the head to be moved inwardly along the pin. Hence, the locking mechanism of the anti-theft device acts as a one-way coupling, which may be rendered inoperative (i.e. to release the head from the pin) only by means of an appropriate unlocking device, said unlocking device only being available to authorized personnel.
U.S. Pat. No. 4,012,813 relates to a fastening device for securing articles together, the device including releasably connected male and female components. The male component comprises a pin, whereas the female component comprises a magnetic retaining insert positioned in a housing for releasably clamping the pin. When joined, the pin cannot be separated from the retainer, unless a special tool is used. Since the insert is of magnetic material, an actuating tool including an electromagnet may be used for actuating the insert to permit removal of the pin. The fastening device is intended to be used in an anti-theft tag, comprising an electrical circuit, which activates an alarm, if the tag has not been properly removed when a checkout point is passed. Similar anti-theft locking devices are disclosed in U.S. Pat. No. 4,221,025, U.S. Pat. No. 4,903,383, U.S. Pat. No. 5,054,172, U.S. Pat. No. 5,031,287 and U.S. Pat. No. 4,483,049.
U.S. Pat. No. 5,140,836 discloses a clamp for use as a theft deterrent device, comprising a U-shaped member having first and second legs including a shelf disposed on the inside of each leg. Furthermore, a clamp housing has a pair of longitudinal channels for receiving the legs of the U-shaped member as well as means provided with a row of teeth for engaging the shelves on the U-shaped member, so as to prevent removal of the U-shaped member from the longitudinal channels. The housing comprises a magnetically attractive element, which when attracted by an external magnetic field is movable to such a position, in which the teeth are disengaged from the shelves, so that the U-shaped member may be removed from the housing. A similar magnetically releasable clamp is disclosed in U.S. Pat. No. 5,337,459, where an U-shaped member is engaged by means of retaining balls rather than teeth.
A common drawback of the previously known anti-theft devices described above is that the locking mechanism thereof (i.e. the one-way coupling which allows the male portion—pin or U-shaped member—to be inserted into the female portion of the device, while preventing the male portion from being separated from the female portion, unless actuated by the unlocking device) may be actuated by other means than the intended unlocking device. For instance, the knowledge about the magnetically releasable locking mechanism inside conventional anti-theft devices is most likely well-spread among criminal individuals, such as shop-lifters. Hence, a shop-lifter may easily bring his or her own permanent magnet, or possibly electromagnet, into the shop and use the magnet for releasing the male portion from the female portion, so as to remove the anti-theft device from the desired article. Then, nothing stops the thief from stealing the article.
SUMMARY OF THE INVENTION
An object of the present invention is to prevent unauthorized people from removing the anti-theft devices from protected articles by using their own “home-made” unlocking device, such as a permanent magnet or, possibly, a battery-powered electromagnet.
The object of the invention is achieved for anti-theft devices, comprising first and second housing elements and a locking mechanism for securing a male portion (e.g. a pin) of the second housing element to a female portion (comprising e.g. spring biased retaining balls) of the first housing element, the locking mechanism being arranged to release the male portion from the female portion, when actuated by an unlocking device operated by an authorized person, by providing the locking mechanism with a thermally controllable element, which is arranged to assume a first position during normal temperatures, wherein the locking mechanism is kept in a locked state, and a second position when heated to temperatures above a predetermined limit, wherein the locking mechanism is caused to release the male portion from the female portion of the first and second housing elements.
Other objects, aspects and features of the present invention are defined by the subsequent dependent claims.
REFERENCES:
patent: 3806910 (1974-04-01), Keifer et al.
patent: 4072867 (1978-02-01), Goodlaxson
patent: 4380097 (1983-04-01), Keifer
patent: 4575706 (1986-03-01), Heidman, Jr.
patent: 46
Quinones Christian
Tyren Carl
Merchant & Gould P.C.
RSO Corporation N.V.
Trieu Van T.
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