Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-03-23
2001-02-20
Mullen, Thomas (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S572100
Reexamination Certificate
active
06191692
ABSTRACT:
A theft-deterrent device and a locking element and a release device for a theft-deterrent device.
The present invention relates to a theft-deterrent device which is intended to be attached to and locked on theft-attractive goods and which is designed to co-act with a release device for releasing the theft-deterrent device from said goods. The theft-deterrent device comprises a first element consisting in a base element and a connecting element which projects out from the base element and which is intended to be inserted through the item of goods to be protected, and a locking element which can be attached to the connecting element and locked thereon against movement away from the base element, so as to hold the theft-deterrent device securely on item of goods concerned. The invention also relates to a locking element and a release device for a theft-deterrent device.
Anti-theft devices, or theft deterrents, of this kind are used with the intention of preventing or deterring the theft of theft-attractive goods, such as clothing, bags, handbags, suitcases and other retail articles that can be easily carried. A device of this kind is intended to be attached to an item of goods in a manner such that the device can only be released with the aid of a special release device, to which potential thieves are assumed not to have access. The intention is, of course, that only authorised persons, for instance till operators, or cash register operators, shall have access to such a release device. Attempts to remove the theft-deterrent device without the aid of the special release device will greatly impair the goods, or render them unusable, either by tearing the goods or by causing a fragile ampul provided in the theft-deterrent device and containing a staining substance to fracture and release the staining substance so as to stain the goods or damage the goods in some other way. The theft-deterrent device may also carry an alarm element forming part of an alarm system either as an alternative to or complementary to one or more ampuls containing a staining or marking substance, said alarm system being adapted to be triggered by a sensor arrangement at the exits of the store in which the theft-attractive goods are offered for sale.
Normally, theft-deterrent devices of the kind defined in the introduction have locking elements that can be released with the aid of magnetic release devices. Consequently, so-called pirate release devices have been developed and used with some success to release the locking element unlawfully from the connecting element without the aid of the special release device and thereby render the theft-deterrent device inactive.
The object of the present invention is to provide a structurally simple and therewith inexpensive theft-deterrent device of the aforesaid kind that is more secure against unlawful release of the locking function of said device than earlier known devices of this kind.
This object is achieved in accordance with the invention by means of a theft-deterrent device, a theft-deterrent device locking element and an associated release device that have the characteristic features set forth in the following Claims.
According to the invention, the locking element includes a locking unit that is made either completely or partially of a material that has special memory properties, i.e. a material that when deformed will strive to return to its original form, such as its shape or state, in response to a change in temperature. Metal alloys that have special memory properties, so-called memory metals, are preferably used in this regard. The term memory metal is a term commonly used to describe metal alloys that have a memory ability, i.e. a material which when subjected to deformation can be caused to return to its original form by changing its temperature. A memory metal can have memory properties in the form of a so-called one-way memory, meaning that an article subjected to deformation will return to its original form in response to a temperature change, the number of times that this procedure can be effected being almost unlimited. A memory metal may also have two-way memory properties, meaning that in addition to returning to its original form in response to an increase in temperature, the metal is also able to take a predetermined deformed form in response to a lowering of the temperature.
Ordinary metal alloys that have memory properties are comprised of a number of variants within the nickel-titanium system. Other examples of possible alloys are copper-zinc-aluminium alloys, aluminium-nickel alloys, copper-aluminium-nickel alloys and iron-based memory metals.
Plastic materials and ceramic materials are examples of other possible materials having memory properties.
Thus, in accordance with the invention, the connecting element is released from the locking element by movement of a locking unit in the locking element to a release position by means of a temperature change of the locking unit. This temperature change can be achieved in many different ways within the scope of the invention and may be an increase or a decrease in temperature.
In one preferred embodiment of the invention, the change in temperature in the locking unit is achieved by heating a memory metal in the locking unit inductively. Inductive heating of a metal object, such as the locking unit in this case, said locking unit being made either completely or partially of a memory metal, is achieved by placing the locking unit within or closely adjacent to a coil through which an alternating current passes. Eddy currents are thus induced in the metal and heat is generated in the proximity of the eddy currents, due to the resistance in the material concerned. In this preferred embodiment of the invention, a coil supplied with alternating current is disposed in the release device in a manner which enables the locking unit in said locking element to be placed in or in the close proximity of the coil and therewith to be heated inductively so as to release the connecting element.
This inductive heating of the locking unit has important advantages, since the heat is developed immediately and directly in the actual metal of the locking unit. The change in the temperature of the memory metal required to change the form of said locking unit takes place very rapidly, so as to enable a quick release of the connecting element from the locking element.
Within the scope of the invention, temperature changes in the material can also be achieved in other ways, for instance by utilising the so-called Peltier effect, by delivering heat or cold directly to the material through a specially designed nozzle, or in some other suitable way.
A temperature change of the magnitude required to change the form of the locking unit to a release form cannot be achieved readily by an unauthorised person, which makes pirate equipment for releasing the inventive theft-deterrent device from an item of goods difficult to manufacture. An unauthorised person cannot tell from the outside of the device how the two elements can be released from one another. The locking unit is conveniently enclosed in a plastic casing which softens when heated, which makes endeavours to unlawfully release the theft-deterrent device by heating the locking unit from outside the locking element difficult to achieve. The locking unit may also be surrounded by an insulating material which makes it difficult, or impossible, to effect the necessary change in temperature of the locking unit by supplying heat or cold thereto from the outside. An ampul containing a staining substance comprised in the theft-deterrent device may include or have externally connected thereto an alarm element which prevents the item of goods to which the theft-deterrent device is attached from being removed from the store or shop so that the theft-deterrent device can be manipulated in some other place.
In one preferred embodiment of the invention, the connecting element is released by a direct and/or indirect change of form, such as its shape, in a direction essentially radially in
Gustavsson Bo
Stoltz Klas
Browdy and Neimark
Fargklamman AB
Mullen Thomas
LandOfFree
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