Sealing fastener with ultrasonic identifier and removal attempt indicator, and ultrasonic reading device for same

• US 5,807,048 A
• Filed: 08/19/1997
• Issued: 09/15/1998
• Est. Priority Date: 09/03/1992
• Status: Expired due to Term

• Current Assignee: The European Atomic Energy Community (Euratom)
• Original Assignee: The European Atomic Energy Community (Euratom)
• Inventors: Toornvliet, Jan, d'Agraives, Bertrand Causse, Mascetti, Ermanno
• Primary Examiner(s): BARRETT, SUZANNE LALE DINO
• Application Number:
  US08/914,242
• Time in Patent Office: 392 Days
• Field of Search: 411/2-5, 411/14, 411/910, 73/760, 73/761, 73/763, 73/627
• US Class Current: 411/2
• CPC Class Codes: F16B 41/005 Measures against unauthorised operation of bolts, nuts or pins F16B23/0007, F16B23/0061, F16B23/0069, F16B23/0076 and F16B31/02 take precedence; locks, keys E05B; for valves, taps or cocks F16K35/00; for pipe-joints with swivel-nuts F16L19/005
• CPC Class Codes: G01L 5/246 using acoustic waves
• CPC Class Codes: G01N 29/24 Probes transducers for acoustic waves B06B, G10K; for measuring G01H

Abstract

A sealing fastener includes a unique identifier device for the individual fastener that enables ultrasonic identification of the device using an ultrasonic fault measuring system, and a frangible element within the fastener integrated with the identifier device that provides an ultrasonic signature indicating an attempt to loosen or remove the fastener when subjected to an ultrasonic signal generated by an ultrasonic fault measuring system. The unique identifier device includes a stack of individual metallic washer elements brazed together, with each washer element including discontinuities or cavities that are randomly arranged with respect to the cavities of the other washers in the stack. The fastener includes relatively movable portions that cause fracture of the frangible element upon any attempt to loosen or remove a fastener after it has been tightened or secured at its sealing location. An ultrasonic reading device includes an adapter that cooperates with the fastener to precisely locate an ultrasonic transducer with respect to the identifier and indicator so that a signature of the identifier and the indicator can be obtained in a single step using a single ultrasonic reading head associated with an ultrasonic fault detector system.

Claims

1. A sealing fastener comprising:

a unique identifier within the fastener;

a fastener loosening attempt or removal indicator within the fastener;

said identifier comprising a unique ultrasonically detectably ultrasonic signature producing pattern of cavities in a core structure;

said indicator comprising a frangible element providing an ultrasonically detectable signature when broken;

said fastener being installable in an element to be sealed by a first motion and removable from such element by a second motion carried out beyond an initial portion of said second motion;

said frangible element arranged in the fastener so as to be rupturable upon the occurrence of said initial portion of said second motion.

2. The sealing fastener according to claim 1, said fastener comprising a bolt including a head portion and threaded shank;

said identifier and indicator being contained in a driving connection device coupled to said head so as to transmit first and second motions applied to said driving connection to said head;

said driving connection device including a first section connectable to a fastener driving device and a second section connectable to said head, said head being drivable at least in said second direction by transmittal of second motion to said head via the first and second sections of the driving connection;

said second section being connected to said frangible element and being connected to said first section so as to be displaced relative to the first section upon the movement over the initial portion of said second motion by said first section while said head remains stationary;

said frangible element spanning said first and second sections and located so as to be broken upon the occurrence of said relative displacement between said first and second sections.

3. A sealing fastener as claimed in claim 2, including a one-way drive device located between said head and said second section and arranged to transmit first motion applied to said driving connection device to said head, but to disengage the connection driving device from the head when second motion is applied to the driving connection device.

4. A sealing fastener according to claim 2, said fastener having a longitudinal axis;

said driving connection device including a conical outer surface symmetrically located relative to said axis.

5. A sealing fastener according to claim 2, wherein said identifier and said indicator are integrated as a singular structural element constituted of a metallic core structure.

6. A sealing fastener according to claim 5, wherein said identifier comprises a stacked assembly of metallic washer elements each having at least one ultrasonically detectable cavity, wherein the washers are assembled with the respective cavities randomly oriented relative to the cavities of other washers of the assembly to produce said unique ultrasonic signature pattern of cavities, said pattern being unique to an individual identifier.

7. A sealing fastener according to claim 6, wherein said fastener has a central longitudinal axis;

and said frangible element is located eccentrically of said axis.

8. A sealing fastener according to claim 1, wherein said identifier and said indicator are integrated as a single structural element constituted of a metallic core structure.

9. A sealing fastener according to claim 8, wherein said unique identifier comprises a stacked assembly of metallic washer elements each having at least one ultrasonically detectable cavity, wherein the washer elements are assembled with their respective cavities randomly oriented relative to the cavities of the other washer elements of the assembly to produce said unique ultrasonic signature pattern of cavities, said pattern being unique to an individual identifier.

10. A sealing fastener according to claim 9, wherein said fastener has a central longitudinal axis;

and said frangible element is located eccentrically of said axis.

11. A sealing fastener according to claim 10, said fastener including a driving connection device, said driving connection device including a conical shaped outer surface symmetrically located relative to said longitudinal axis with the smaller diameter of the conical surface facing away from the fastener.

12. An ultrasonic sealing fastener identification and removal or loosening indicator system, comprising:

a sealing fastener including a unique identifier within the fastener;

a fastener loosening attempt or removal indicator within the fastener;

said identifier comprising a unique ultrasonically detectably ultrasonic signature producing pattern of cavities in a core structure;

said indicator comprising a frangible element providing an ultrasonically detectable signature when broken;

said fastener being installable in an element to be sealed by a first motion and removable from such element by a second motion carried out beyond an initial portion of said second motion;

said frangible element arranged in the fastener so as to be rupturable upon the occurrence of said initial portion of said second motion;

a driving connection device connected to the fastener for transmitting first and second motions from a fastener driving device to the fastener;

an ultrasonic energy transmitting and receiving device including a coupling element arranged to engage the driving connection device and to be positioned upon such engagement in a predetermined location relative to said fastener;

said ultrasonic device being arranged to generate fault signals corresponding to ultrasonic signatures of said identifier and said indicator at said predetermined location.

13. An ultrasonic system according to claim 12,

said fastener including a longitudinal axis;

said driving connection device including a conical portion symmetrically located relative to said axis with the smaller diameter of the conical portion extending away from the fastener;

said coupling element including a conical cavity configured to receive said conical portion in close-fitting relationship;

said ultrasonic energy transmitting and receiving device including an ultrasonic transducer located eccentrically of said longitudinal axis in close proximity to said coupling element;

said indicator being located eccentrically of said axis; and

a transducer motion producer for causing orbital motion of the transducer about said axis.

14. An ultrasonic system according to claim 13, said ultrasonic energy transmitter and receiving device being disposed in a reading head, and including at least one extension tube connected to said reading head for enabling remote manipulation or guidance of said reading head.

15. A method of ultrasonically identifying individual sealing fasteners and detecting attempts to loosen or remove such fasteners, comprising the steps of:

providing a sealing fastener including a unique ultrasonic identifier for the individual fastener, said identifier producing a unique ultrasonic signature when subjected to signals produced by an ultrasonic fault measuring device;

providing the sealing fastener with a frangible fastener loosening attempt or removal indicator, such indicator producing an ultrasonic signature when subjected to signal produced by an ultrasonic fault measuring device indicative of the integrity of the indicator;

providing the fastener with at least two sections that are relatively movable upon attempted loosening of the fastener following installation of the fastener on a device to be sealed and connecting the indicator between the relatively movable sections such that relative movement resulting from an attempted fastener loosening or removal breaks the frangible element;

installing the fastener at a desired location on a device to be sealed and securing the fastener against loosening;

subjecting the fastener identifier and indicator to signals produced by an ultrasonic fault measuring device located in close proximity to said identifier and indicator such that clear ultrasonic signatures of the identifier and indicator are obtained.

16. A method according to claim 15, including providing said sealing fastener with a conical driving connection portion located symmetrically along a longitudinal axis of the fastener and providing the ultrasonic fault measuring device with a conical cavity arranged to receive the conical driving connection portion in close fitting relationship and having an ultrasonic transducer in close proximity to said cavity but located eccentrically of the axis of the cavity;

locating the indicator in the fastener eccentrically of the fastener axis; and

subjecting the indicator to said ultrasonic signals while causing orbital motion of the transducer about said fastener axis.

17. An ultrasonic fault measuring device comprising:

a reading head having an ultrasonic transducer therein;

said reading head including a conical cavity having an axis of symmetry;

said transducer located in close proximity to said cavity and eccentrically of said axis;

said transducer also located to project ultrasonic signals into the cavity along the direction of said axis; and

a device for causing orbital motion of the transducer about said axis while the transducer is energized to produce fault measuring signals.