Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-10-29
2001-01-30
Lee, Benjamin C. (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S572700, C340S572800, C340S551000, C343S702000
Reexamination Certificate
active
06181247
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for monitoring electronically protected items in a monitored area, wherein the device is equipped with a transmitting and/or receiving unit.
1. Background of the Invention
Nowadays, devices for the purpose of electronically protecting goods have a widespread application in department stores and warehouses. Inventory losses due to theft can be decisively reduced by installing such devices. The electronic monitoring devices can usually be found in the entry, or respectively exit areas of department stores and warehouses in order to signal the unauthorized removal of the appropriately secured articles from the sales or storage areas.
The monitoring devices described in the prior art have the most diverse designs. For example, an antenna device is known from European Patent, 0 668 626 A1 a consisting of a housing for receiving the transmitting and receiving antennas and of a frame, which essentially extends along the exterior edge areas of the housing. In connection with the known device it has been provided in particular that the frame element provided at the upper edge of the housing is removable, so that the antenna device can be removed from, or respectively inserted into the housing through the opening made.
2. Summary of the Invention
The object of the present invention is to provide a cost- effective device for monitoring electronically protected articles.
The object is attained in that the device is constructed of individual layers of material, wherein each one of the material layers by itself is flexible and has little strength, while in combination the material layers are distinguished by great rigidity and strength. In accordance with the present invention the effect is employed, wherein by combining individual layers of relatively little stability it is possible in the end to achieve a strength and rigidity which exceeds the sum of the strength and rigidity of the individual layers by a multiple. Since the demands made on the individual material layers—their stability in particular should be mentioned here—can be relatively low, the device in accordance with the present invention can be produced very cost-effectively.
In accordance with an advantageous further embodiment, the device in accordance with the present invention is composed of the following layers: a first lateral wall made of a bendable material, a filler made of a flexible material, a support layer made of a flexible material, whose surface is structured in such a way that it is suitable for receiving the transmitter coils and/or the receiver coils, and a second lateral wall of a bendable material.
To prevent interfering signals coming from outside the monitored zone from reducing the detection rate within the monitored zone, in accordance with a first alternative the first lateral wall is made of a material which shields electromagnetic radiation. All conductive materials can be used as suitable materials. In accordance with a preferred embodiment the lateral wall is made of aluminum. It has been shown that a thickness of the aluminum layer in the millimeter range is completely sufficient.
A variation of the above described embodiment provides that a separate, bendable shielding layer is provided between the first lateral wall and the filer on the side facing away from the monitored zone. This shielding layer is also made of aluminum, which can have a thickness of a few tenths of a millimeter.
In accordance with an advantageous further embodiment of the device in accordance with the present invention it is provided that the individual layers are fixedly connected with each other at least in spots. In the simplest case the layers are glued together.
It has been found to be cost-effective and completely sufficient for achieving the required stability if the filler is made of foamed polystyrene or a foamed filler. When using foamed polystyrene, it has a shape which is designed complementary to the corresponding side of the support layer. If a foamed filler is used, it is applied directly to the appropriate location of the support layer.
In accordance with an advantageous embodiment of the device of the present invention, the support layer is a compressed fiberglass material. The use of an injection-molded element would of course also be possible.
In order to meet the requirements of customary safety standards in public places, the lateral walls of the device in accordance with the present invention are made of a highly non-flammable material.
Furthermore, an advantageous further development of the device in accordance with the present invention proposes the provision of lateral profiles and at least one cover profile, which enclose the lateral areas of the material layers.
The present invention will be explained in greater detail by means of the following figures.
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Bremer Peter
Clancy Terence
Douglas Anthony
Schneider Peter
Stocks David
Jones Tullar & Cooper P.C.
Lee Benjamin C.
Meto International GmbH
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