Security enclosure manufacture

• US 5,539,379 A
• Filed: 03/03/1995
• Issued: 07/23/1996
• Est. Priority Date: 09/22/1992
• Status: Expired due to Term

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: MacPherson, Hugh
• Primary Examiner(s): SWANN III, GLEN R
• Application Number:
  US08/397,159
• Time in Patent Office: 508 Days
• Field of Search: 340/550, 109/42, 109/41, 109/38, 206/807
• US Class Current: 340/550
• CPC Class Codes: G08B 13/128 the housing being an electronic circuit unit, e.g. memory or CPU chip protecting computer components in secure or tamper resistant housings G06F21/86; protecting computer input devices, e.g. keyboards G06F21/83
• CPC Class Codes: Y10S 206/807 Tamper proof

Abstract

A security enclosure (20) includes an inner enclosure defined by a first electrically insulating sheet (60) carrying a layer (56) of electrically responsive material on an outer side, the sheet (60) being folded and having edges (100) in overlapping relation and adhered to one another to define the inner enclosure. A detector (80) is provided for detecting separation of the electrically responsive material (56) from the sheet (60) and is located inside the inner enclosure. An outer enclosure is defined by a second electrically insulating sheet (44) wrapped about and adhered to the inner enclosure and also having edges in overlapping relation.

Claims

1. A method of forming a security enclosure (20) comprising the steps:

providing a first electrically insulating sheet (60) carrying a layer (56) of electrically responsive material on one side;

providing detection means (80) for detecting separation of the electrically responsive material from the sheet (60);

connecting said detection means (80) to the layer (56);

folding said first electrically insulating sheet (60) to define an inner enclosure with said electrically responsive layer (56) extending over an external surface thereof and said detection means (80) located therewithin;

providing a second electrically insulating sheet (44);

providing adhesive material (46,

     54) on at least one of said external surface and said second electrically insulating sheet (44); and

wrapping said second electrically insulating sheet (44) about said inner enclosure to encapsulate said inner enclosure.

2. The method of claim 1 wherein a low tensile strength material (58) having lower cohesion than adhesion is located between the first electrically insulating sheet (60) and the electrically responsive material (56).

3. The method of claim 1 wherein the electrically responsive material is provided in the form of one or more lines (56).

4. The method of claim 3 wherein adhesive material is provided at selected edge portions (100) of said first electrically insulating sheet (60) and on folding said first electrically insulating sheet (60) to define the inner enclosure said selected edge portions are placed in overlapping relation.

5. The method of claim 4 for use in forming a box-like security enclosure (20) and comprising the further steps of:

providing the first electrically insulating sheet (60) with major wall forming portions (100) carrying said electrically responsive lines and intermediate wall forming portions (102) located between the major wall forming portions;

folding said intermediate wall forming portions (102) to permit said major wall forming portions (100) to define corners of a box-like enclosure including folding selected intermediate wall forming portions (102) to produce electrically responsive line to electrically responsive line interfaces;

providing first wings (104) of electrically insulating sheet extending beyond an area of said first electrically insulating sheet (60) carrying said electrically responsive line (56); and

locating said first wings (104) between said folded selected intermediate wall forming portions (102) to provide electrically responsive line to electrically insulating material interfaces therebetween.

6. The method of claim 5 comprising the further steps of:

folding further selected intermediate wall portions (102) to produce electrically insulating material to electrically insulating material interfaces;

providing second wings (106) of electrically insulating sheet carrying portions of said electrically responsive line; and

locating said second wings (106) between said folded further selected intermediate wall portions (102) to provide electrically responsive line to electrically insulating material interfaces therebetween.

7. The method of claim 5 in which said electrically responsive material (56) is provided over a substantially rectangular area of said first electrically insulating sheet (60).

8. The method of claim 4 wherein said second electrically insulating sheet (44) is wrapped about said inner enclosure with edge portions of said second electrically insulating sheet in overlapping relation.

9. The method of claim 8 in which the overlapping edge portions of said second electrically insulating sheet (44) are formed on the inner enclosure spaced from the overlapping edge portions of said first electrically insulating sheet (60).

10. The method of claim 8 in which the overlapping edge portions of said first electrically insulating sheet (60) and the overlapping edge portions of said second electrically insulating sheet (44) are formed of opposite hand.

11. The method of claim 1 further comprising;

providing said first electrically insulating sheet (60) with lines of electrically responsive material (56,

     62) on each side, the lines (56) on one side extending obliquely relative to the lines (62) on the other side and the lines (56,

     62) being interconnected at edge portions of the sheet (60) to form a plurality of conductors (LA, LB, LC, LD) so dividing the sheet into a number of relatively small areas that attempted penetration of the sheet (60) damages the lines (56,

     62), one edge portion of the sheet including a plurality of first switch means;

selectively configuring the switch means to connect each one of the lines (56) on one side of the sheet with a selected one of a plurality of lines (62) on the other side of the sheet; and

connecting ends of the conductors (LA, LB, LC, LD) to the detecting means (80) for detecting damage to the lines.

12. A security enclosure (20) comprising:

an inner enclosure defined by a first electrically insulating sheet (60) carrying a layer (56) of electrically responsive material on an outer side, the sheet (60) being folded and having edges (100)in overlapping relation and adhered to one another to define the inner enclosure;

detecting means (80) for detecting separation of the electrically responsive material (56) from the sheet (60) and said means being located inside said inner enclosure; and

an outer enclosure defined by a second electrically insulating sheet (44) wrapped about and adhered to said inner enclosure and having edges in overlapping relation.

13. The security enclosure of claim 12, in which a low tensile strength material (58) having lower cohesion than adhesion is located between the first electrically insulating sheet (60) and the electrically responsive layer (56).

14. The security enclosure of claim 12 in which the electrically responsive material is provided in the form of one or more lines (56).

15. The security enclosure of claim 12, in which the overlapping edges of said second insulating sheet (44) are spaced from the overlapping edges of said first electrically insulating sheet (60).

16. The security enclosure of claim 12, in which the overlapping edges of said first electrically insulating sheet (60) and the overlapping edges of said second insulating sheet (44) are of opposite hand.

17. The security enclosure of claim 12, in which the first electrically insulating sheet forms part of an outer detection layer (248) of the inner enclosure and the inner enclosure further includes an inner detection layer the inner detection layer extending beyond at least one edge of the inner detection layer to provide at least one overlapping edge of the inner enclosure with a first portion (240) in which edges of both detection layers overlie the other edges of the layers and a second portion (241) in which only the outer detection layer overlies the other edges of the layers.

18. The security enclosure of claim 12 in which lines of electrically responsive material (56, 62) are provided on each side of said first electrically insulating sheet (60), the lines (56) on one side extending obliquely relative to the lines (62) on the other side and the lines being interconnected at edge portions (60) of the sheet to form a plurality of conductors (LA, LB, LC, LD) so dividing the sheet into a number of relatively small areas that attempted opening of the enclosure damages the lines (56, 62), one edge portion of the sheet including a plurality of first switch means which are selectively configured to connect each one of the lines (56) on one side of the sheet (60) with a selected one of a plurality of lines (62) on the other side of the sheet (60), and further including connecting means (76) for connecting ends of the conductors to the detecting means (80) for detecting damage to the lines.

19. The security enclosure of claim 18 wherein the lines (56) on one side of the sheet (60) are connected to the lines (62) on the other side of the sheet (80) at spaced points (70) along the edges of the sheet (60), the points on one side of the sheet being in register with the points on the other side of the sheet.

20. The security enclosure of claim 19 wherein at the edge portion of the sheet provided with first switch means, each line (56) on one side of the sheet overlies a plurality of lines (62) on the other side of the sheet, a point (70) being provided on each side of the sheet at the location of each overlap, but only one point (70a) on each line (56, 62) providing a connection.

21. The security enclosure of claim 19 wherein the lines (56, 62) on opposite sides of the sheet are interconnected at each pair of connected registering points (70a) by a semi-conductive or conductive material (74) extending through a hole (72) formed in the sheet (60) at the registering points (70).

22. The security enclosure of claim 12 in which:

lines (56,

     62) of electrically responsive material are provided on each side of said first electrically insulating sheet (60), the lines (56) on one side of the sheet extending obliquely relative to the lines (62) on the other side and being connected thereto at edge portions of the sheet to form a plurality of conductors (LA, LB, LC, LD), so dividing the sheet into a number of relatively small areas that attempted opening of the enclosure damages one or more of the lines (56,

     62).

23. The security enclosure of claim 12 in which the first electrically insulating sheet (60) forms part of an outer detection layer (48) of the inner enclosure and the inner enclosure includes a further inner detection layer (110), said inner detection layer (110) comprising a third electrically insulating sheet (124) carrying lines (122, 126) of electrically responsive material on each side, the lines (122, 126) being arranged in parallel and having a width and pitch such that the lines (122, 126) collectively provide electrically responsive material on said third electrically insulating sheet (124) on at least one side over the whole extent thereof, penetration of the enclosure damaging at least one of the lines (122, 126) and which damage is detectable by said detecting means (80).

24. The security enclosure of claim 23, further comprising a still further inner detection layer (108) similar to said further inner detection layer (110) and adhered thereto with the lines (123, 127) of said still further inner detection layer (108) extending perpendicular to the lines (122, 126) of said further inner detection layer (110).