FR2594882A1 - Device intended for increasing the efficiency of metal detectors, more particularly for the doors of public buildings - Google Patents

Abstract

The subject of the invention relates to a device intended for increasing the efficiency of metal detectors. It consists of the combination of a door leaf free of any metallic part, that is to say frame, rivets, nails or even of any locking element with earthing 12, 13 of the fixed frame or hinges avoiding any transfer of static electricity. It applies more particularly to doors giving access to monitored areas at the entrance of public establishments, banks and the like, in order to remove the interferences likely to perturb the metal detection signalling equipment.

Description

 The object of the invention relates to a device intended to increase the efficiency of metal mass detectors.

I1 applies more particularly to doors giving access to the monitored areas at the entrance to public establishments
banks and others, in order to suppress interference disrupting detector signals.

 It is known practice to use metal mass detector devices to signal the transport of objects liable to be used for criminal offenses, especially when accessing banks or other establishments directly open to the public, detectors are installed for this purpose. the circuit is made by opening the door; it sometimes happens that certain metallic masses in movement locks, fittings, frames or others create interference disturbing the signal and oblige to increase the power of these devices to compensate for this magnetic turbulence which also makes the desired control imprecise.

 The device according to the invention eliminates these drawbacks and makes it possible to avoid any interference in the reception of the signal and ensures absolute precision with reduced or normal transmission power.

 I1 is constituted by the combination of a door leaf having no metal part, that is to say, frame, riveting, nailing or even locking element with an earthing of the frame or hinges preventing any displacement of electricity static.

In the accompanying drawings, given by way of nonlimiting example, of one of the embodiments of the subject of the invention
FIG. 1 shows, seen in cross section, a frame and door sector made of dielectric material or of non-conductive synthetic resin without any metallic element.

 Figure 2 is an overview of a security device equipped with detectors.

 Figure 3 shows a view of the earthing of a hinge or hinge hinge of a leaf in dielectric or synthetic material.

 The door 1 is entirely made of non-conductive, dielectric and insulating material without any metallic element in its mass or on all its internal and external surfaces.

 It includes incorporated in the insulating mass, the keeper 2 receiving the metal bolt 3 of the frame or metal frame 4.

 The frames, locks and the like being static metallic masses in no case disturb the emission to the receiver of mass detectors 5, 6, (fig 2) placed on either side of the access corridor 7 closed by the doors. 8, 9.

 Preferably, the metal reinforcements formed by the uprights 10, 11 are earthed 12, 13 in order to avoid the effects of static currents or their accumulation which can prolong them.

 The hinges 15 connecting the dielectric doors to the metal frame with or without threshold 14 are also depolari rised by an earthing 16.

 It follows that as soon as a person crosses the threshold of the corridor 7 only the metallic mass of which he is the carrier will activate the detectors 4, 5 the waves of which will no longer be disturbed by the metallic parts due to the movement of the leaves and their mounts or locks.

The effectiveness of the alarm will be increased in
considerable proportions and the door 9 can be blocked automatically while the door 8 opens or closes the circuit actuating the detectors.

 The dielectric door can be shielded by the use of a resistant synthetic resin with lamination of lightened panels thus reducing the risk of burglaries.

 However, the shapes, dimensions and arrangements of the various elements may vary, as moreover the insulating or dielectric materials for manufacturing door leaves having no metallic element without changing the general design of the invention which has just been described.

Claims (3)

 10 Device intended to increase the effectiveness of metal mass detectors applying more particularly to the doors closing the access corridors of public establishments, such as banks, aerodromes and others by eliminating the interference caused to the detection apparatus by the metal parts , fittings, locks or other elements structuring the leaves and the possible evacuation of accumulations of static electricity which may occur on non-conductive or dielectric surfaces, characterized by a leaf (1) entirely dielectric or made of synthetic resin incorporated by molding , the keeper (2) the door (8) for closing is strictly without any metal part either in its mass or on its external surfaces, while the metal frame (4) supports the locks, bolts (3) and other static parts being specified that the uprights of the frame forming the frame (10, 11) are provided with an earth (12, 13), then q ue the metal mass detectors (5, 6) are positioned on either side of the access corridor (7), the hinges (15) and threshold (14) being preferably grounded (16).  20 Device according to claim 1 characterized in that the one-piece door entirely of molded dielectric material opens or closes the circuit of the detectors (5, 6) which can also by electronic circuit or other block the door (9) in the event of signaling of a metallic object passage.  30 Device according to claim 1, characterized in that the door can be constituted by the use of resin of different hardness, density and resistance to produce burglary-resistant shields.