Electronic seal

• US 5,447,344 A
• Filed: 03/29/1994
• Issued: 09/05/1995
• Est. Priority Date: 03/29/1993
• Status: Expired due to Fees

• Current Assignee: Stoba AG
• Original Assignee: Encrypta Electronics Limited
• Inventors: Hayward, Gilbert O.
• Primary Examiner(s): Cuomo, Peter M.
• Assistant Examiner(s): Millner, Monica E.
• Application Number:
  US08/219,364
• Time in Patent Office: 525 Days
• Field of Search: 292/246, 292/248, 292/321, 292/320, 292/328, 292/329, 292/307 R, 292/307 B
• US Class Current: 292/246
• CPC Class Codes: G09F 3/0394 with violation indication by generating a random number random number generators G06F7/58, G07C15/00
• CPC Class Codes: Y10T 292/087 Loops
• CPC Class Codes: Y10T 292/48 Seals
• CPC Class Codes: Y10T 292/516 Sliding catch, seal

Abstract

An electronic seal comprises a housing (12), a cord (14) with one end fixed to the housing (12) and a free end which can be passed through a door catch or the like and releasably connected to the housing (12), an electronic circuit within the housing (12) arranged to generate one of a number of unique codes when a switch (70) in the housing (12) is actuated on connection or disconnection of the cord (14) to or from the housing (12) and a display device (18) which can display the unique code. The cord (14) has a series of regularly spaced enlargements (36), and the interior of the housing (12) has a plurality of teeth (40) arranged so that when a length of cord (14) at its free end is inserted into the housing (12) the enlargements (36) can fit between the teeth (40) to hold the cord (14) against withdrawal from the housing (12). A slide (16 ) is movable in the housing (12) between an open position in which the cord (14) can be inserted into and withdrawn from the housing (12) and a locking position in which it retains the enlargements (36) in engagement with the teeth (40). The switch (70) has an actuating member (72) projecting into the space between two of the teeth (40), so that the switch is actuated when the length of cord (14) is moved into or out of engagement with the teeth (40). The fixed end of the cord (14) is connected permanently to the housing (12) by engagement of enlargements (36) on the cord (14) with a further set of teeth in the housing (12). The cord (14) is held in engagement with the further teeth by the slide (16), when the slide (16) is in the open or locking position. The slide (16) is movable from a third position in which the fixed end of the cord (14 ) can be inserted into the housing (12) before the seal is first used, but is then prevented from being moved back to the third position.

Claims

1. An electronic seal comprising a housing, a flexible element extending from the housing and having a free end which can be passed through a door catch means for releasably connecting the free end of the flexible element to the housing, an electronic circuit within the housing arranged to generate one of a number of unique codes on receipt of an electrical signal and to store the generated code, display means on the housing adapted to display the generated code, and a switch on the housing actuated on connection or disconnection of the flexible element to the housing to provide an electrical signal to actuate the electronic circuit, in which the flexible element is a cord having a series of regularly spaced enlargements, and the means for releasably connecting the free end of the cord to the housing comprises a passage in the housing into which a length of the cord can be inserted, a plurality of teeth in the housing adapted to fit between enlargements of the cord, so that when the length of cord is inserted into the housing each enlargement of the length of cord can fit between two adjacent teeth to hold the cord against withdrawal from the housing, and a slide movable in the housing between a first position in which the cord can be inserted and removed from the passage, and a second position in which the slide retains the enlargements in engagement with the teeth, and the switch has an actuating member projecting between two of the teeth, so as to be engaged by one of the enlargements on the cord when it is engaged between the teeth, so that the switch is actuated when the length of cord is moved into or out of engagement with the teeth.

2. An electronic seal as claimed in claim 1, in which the flexible element comprises a series of balls of plastic moulded onto a plastic cord to form the enlargements.

3. An electronic seal as claimed in claim 1 in which the housing is a rectangular parallelepiped, and the passage extends between openings in two opposite side walls of the housing, so that the flexible element can be inserted from either side of the housing.

4. An electronic seal as claimed in claim 3, in which the passage is formed between a first wall extending between the side walls of the housing and a second wall formed on the slide, the teeth projecting from the first wall, so that on movement of the slide from the first to the second position, the second wall can engage the enlargements of the flexible element to move them into engagement with the teeth.

5. An electronic seal as claimed in claim 1, in which the slide has an arm formed with a detent which is resiliently biased to move into engagement with an abutment surface on movement of the slide to the second position, the engagement holding the slide in the second position, and the arm being movable manually to move the detent out of engagement with the abutment surface to allow it to be moved from the second position.

6. An electronic seal as claimed in claim 5, in which the arm has a grip portion which projects through an opening in the housing and which can be gripped by the user to enable the arm to be moved to release engagement of the detent from the abutment surface and to enable the slide to be moved between the first and second positions.

9. An electronic seal as claimed in claim 2, in which the housing is a rectangular parallelepiped, and the passage extends between openings in two opposite side walls of the housing, so that the flexible element can be inserted from either side of the housing.

10. An electronic seal as claimed in claim 9, in which the slide has an arm formed with a detent which is resiliently biased to move in engagement with an abutment surface on movement of the slide to the second position, the engagement holding the slide in the second position, and the arm being movable manually to move the detent out of engagement with the abutment surface to allow it to be moved from the second position.

11. An electronic seal as claimed in claim 4, in which the slide has an arm formed with a detent which is resiliently biased to move in engagement with an abutment surface on movement of the slide to the second position, the engagement holding the slide in the second position, and the arm being movable manually to move the detent out of engagement with the abutment surface to allow it to be moved from the second position.

12. An electronic seal as claimed in claim 10, in which the arm has a grip portion which projects through an opening in the housing and which can be gripped by the user to enable the arm to be moved to release engagement of the detent from the abutment surface and to enable the slide to be moved between the first and second positions.

7. An electronic seal comprising a housing, a flexible element extending from the housing and having a free end which can be passed through a door catch, means for releasably connecting the free end of the flexible element to the housing, an electronic circuit within the housing arranged to generate one of a number of unique codes on receipt of an electrical signal and to store the generated code, display means on the housing adapted to display the generated code, and a switch on the housing actuated on connection or disconnection of the flexible element to the housing to provide an electrical signal to actuate the electronic circuit, in which the flexible element is a cord having a series of regularly spaced enlargements, and the means for releasably connecting the free end of the cord to the housing comprises a passage in the housing into which a length of the cord can be inserted, a plurality of teeth in the housing adapted to fit between enlargements of the cord, so that when the length of cord is inserted into the housing each enlargement of the length of cord can fit between two adjacent teeth to hold the cord against withdrawal from the housing, and a slide movable in the housing between a first position in which the cord can be inserted and removed from the passage, and a second position in which the slide retains the enlargements in engagement with the teeth, and the switch has an actuating member projecting between two of the teeth, so as to be engaged by one of the enlargements on the cord when it is engaged between the teeth, so that the switch is actuated when the length of cord is moved into or out of engagement with the teeth, and in which the fixed end of the flexible element is retained in the housing by engagement of the enlargements on a length of the flexible element at the fixed end of the flexible element with a second set of teeth formed on the slide, the second set of teeth engaging the enlargements when the slide is in each of the said first and second positions, and the slide being movable to a third position in which the teeth on the slide are withdrawn from engagement with the flexible element, so that the flexible element can be inserted into the housing;

and

in which the housing has a second passage to receive the length of flexible element at the fixed end when it is engaged with the second set of teeth, the further passage extending between openings in two opposite side walls of the housing, so that the flexible element can be inserted from either side of the housing.

8. An electronic seal as claimed in claim 7, in which there is provided in the housing a spring-loaded locking element which bears against the slide when the slide is in the third position and which, on movement of the slide away from the third position after insertion of the fixed end of the flexible element, moves to a position in which it prevents movement of the slide back to the third position.

15. An electronic seal as claimed in claim 7, in which there is provided in the housing a spring-loaded locking element which bears against the slide when the slide is in the the third position and which, on movement of the slide away from the third position after insertion of the fixed end of the flexible element, moves to a position in which it prevents movement of the slide back to the third position.

13. An electronic seal as claimed in claim 13, in which the fixed end of the flexible element is retained in the housing by engagement of the enlargements on a length of the flexible element at the fixed end of the flexible element with a further set of teeth formed on the slide, the further set of teeth engaging the enlargement when the slide is in each of the said first and second positions, and the slide being movable to a third position in which the teeth on the slide are withdrawn from engagement with the flexible element, so that the flexible element can be inserted into the housing.

14. An electronic seal as claimed in claim 13, in which there is provided in the housing a spring-loaded locking element which bears against the slide when the slide is in the the third position and which, on movement of the slide away from the third position after insertion of the fixed end of the flexible element, moves to a position in which it prevents movement of the slide back to the third position.

16. An electronic seal comprising a housing, a flexible element extending from the housing and having a free end which can be passed through a door catch, means for releasably connecting the free end of the flexible element to the housing, an electronic circuit within the housing arranged to generate one of a number of unique codes on receipt of an electrical signal and to store the generated code, display means on the housing adapted to display the generated code, and a switch on the housing actuated on connection or disconnection of the flexible element to the housing to provide an electrical signal to actuate the electronic circuit, in which the flexible element is a cord having a series of regularly spaced enlargements, and the means for releasably connecting the free end of the cord to the housing comprises a passage in the housing into which a length of the cord can be inserted, a plurality of teeth in the housing adapted to fit between enlargements of the cord, so that when the length of cord is inserted into the housing each enlargement of the length of cord can fit between two adjacent teeth to hold the cord against withdrawal from the housing, and a slide movable in the housing between a first position in which the cord can be inserted and removed from the passage, and a second position in which the slide retains the enlargements in engagement with the teeth, and the switch has an actuating member projecting between two of the teeth, so as to be engaged by one of the enlargements on the cord when it is engaged between the teeth, so that the switch is actuated when the length of cord is moved into or out of engagement with the teeth, and in which the fixed end of the flexible element is retained in the housing by engagement of the enlargements on a length of the flexible element at the fixed end of the flexible element with a further set of teeth formed on the slide, the further set of teeth engaging the enlargements when the slide is in each of the said first and second positions, and the slide being movable to a third position in which the teeth on the slide are withdrawn from engagement with the flexible element, so that the flexible element can be inserted into the housing.