Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1995-03-03
1996-07-23
Swann, Glen
Communications: electrical
Condition responsive indicating system
Specific condition
109 42, 206807, G08B 1302
Patent
active
055393799
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to the manufacture of security enclosures, and more particularly, but not exclusively, to the manufacture of security enclosures for giving warning, or destroying or erasing information, if interference is made with the enclosure with the aim of gaining access to an object within the enclosure. The invention has particular application to security enclosures having walls formed of flexible laminates which have been folded to form the enclosures.
BACKGROUND OF THE INVENTION
It is known to provide security enclosures with walls or sheets incorporating coils, meshes or grids of electrically responsive material and to monitor certain electrical characteristics of the material to provide an indication when the sheet containing the material has been pierced or an attempt has been made to open the enclosure through other means. Detection of such an attempt may activate an alarm, destroy the material or object within the enclosure, or erase information if the object within the enclosure, for example, contains sensitive magnetically recorded information. Examples of such enclosures are disclosed in PCT International Application Publication No. WO87/06749 to Wolf, U.K. Patent No. 1,375,926 to GAO Gesellschaft Fur Automation und Organisation mbH, U.S. Pat. No. 4,785,743 to Dalphin and European Patent Publication No. 277,679 to Seculock BV. However, the present invention is more closely related to security enclosures of the form disclosed in U.K. Patent Application No. GB 2220513A, to W. L. Gore and Associates, Inc. The disclosed security enclosures are formed from layers of flexible material including a matrix of diagonally extending semi-conductive lines printed onto a rectangular thin insulating film. The matrix of lines forms a continuous conductor which is broken if attempts are made to penetrate the film. The circuit is monitored by opening the conductor at one point and measuring the change of resistance between the two ends of the circuit.
The Gore security enclosure also includes a further protective laminate comprising two flexible layers of semi-conductive fibrous material separated by a layer of insulating material. The lengths of the fibres of the fibrous material are greater than the thickness of the layer of insulating material so that piercing the enclosure forces fibres from one fibrous layer to penetrate the insulating layer and contact the other fibrous layer to produce a detectable change in an electrical characteristic of the layers.
Further, the Gore application discloses enclosures in the form of shallow, rectangular envelopes formed simply by folding the rectangular laminate about a single axis and then securing the edges of the laminate to one another to form the envelope.
Security enclosures in the form of wedge-shaped, cuboid and cube form are disclosed in U.K. Patent Application GB 2258075A (W. L. Gore & Associates (UK) Ltd). in which a laminate is folded about a plurality of fold lines to form the enclosures. This facilitates formation of enclosures for containing objects that are other than thin and flat.
Further improved security enclosures are also described in the W. L. Gore & Associates (UK) Ltd. U.K. Patent Applications GB 2256956A, GB 2256957A and GB 2256958A, each of which describes features for increasing the difficulty of gaining unauthorised access to the enclosure. In GB 2256956A two layers of semi-conductive fibrous material are separated by a layer of auto-pyrotechnic insulating material. In addition to detecting physical penetration, as discussed above with reference to GB 2220513A, if a laser or other elevated temperature cutting means penetrates the layers the laser ignites the auto-pyrotechnic material and the subsequent decomposition of the layer will result in the fibrous layers coming into contact with one another.
In GB 2256957A, a matrix of semi-conductive lines is printed on a thin insulating film, the matrix of lines forming a plurality of conductors which are individually monitored. The lines extend over both sides
REFERENCES:
patent: 3763795 (1973-10-01), Weltz, Jr.
patent: 4785743 (1988-11-01), Dalphin
patent: 4972175 (1990-11-01), MacPherson
patent: 5049854 (1991-09-01), Wolf
patent: 5224430 (1993-07-01), MacPherson
patent: 5285734 (1994-02-01), MacPherson
patent: 5289785 (1994-03-01), MacPherson et al.
Samuels Gary A.
Swann Glen
W. L. Gore & Associates (UK) Ltd.
LandOfFree
Security enclosure manufacture does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Security enclosure manufacture, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Security enclosure manufacture will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-715996