Fastener incorporating removable ultrasonic transducer

• US 4,295,377 A
• Filed: 07/12/1979
• Issued: 10/20/1981
• Est. Priority Date: 07/12/1979
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: General Dynamics Corporation
• Inventors: Couchman, James C.
• Primary Examiner(s): Ciarlante, Anthony V.
• Application Number:
  US06/057,057
• Time in Patent Office: 831 Days
• Field of Search: 73/761, 73/629, 73/597, 116/DIG. 34, 310/336
• US Class Current: 73/761
• CPC Class Codes: B25B 23/14 Arrangement of torque limiters or torque indicators in wrenches or screwdrivers couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L
• CPC Class Codes: F16B 2031/022 using an ultrasonic transducer
• CPC Class Codes: G01L 5/246 using acoustic waves
• CPC Class Codes: G01N 2291/02827 Elastic parameters, strength or force
• CPC Class Codes: G01N 2291/2691 Bolts, screws, heads
• CPC Class Codes: G01N 29/24 Probes transducers for acoustic waves B06B, G10K; for measuring G01H

Abstract

A threaded fastener incorporating a removable ultrasonic transducer for obtaining preload measurements as well as other measurements for quality control inspection or for monitoring purposes. The transducer may be removed for repair or replacement purposes.

Claims

1. A fastener, comprising:

a shank having a head at one end and threads formed at the other end,

an acoustic transducer located in a container means and affixed therein such that said transducer and said container means are an integral unit, and

attaching means for removably attaching said container means to one end of said fastener with said acoustic transducer being acoustically coupled to said fastener to allow pulse-echo measurements to be obtained while said fastener is torqued in place with a wrench means,

said attaching means being separate from the wrench means whereby when the wrench means is removed from said fastener, said container means remains attached to said fastener,

the entire portion of said fastener between said container means and the end of said fastener opposite said container means being of solid metal throughout.

2. The fastener of claim 1, wherein:

said transducer is affixed in said container means with potting material.

3. The fastener of claim 11, wherein:

said container means is located in a shallow opening formed in said one end of said fastener and removably attached therein.

4. The fastener of claim 3, wherein:

said attaching means comprises removable holding means located in said opening.

5. The fastener of claim 4, comprising:

spring biasing means located in said opening and seated against said removable holding means and said container means.

6. The fastener of claim 3, wherein:

said shallow opening is formed in said head only of said fastener.

7. The fastener of claim 1, wherein:

said container means is removably attached to the exterior surface of said one end of said fastener.

8. The fastener of claim 7, wherein:

said attaching means comprises cap means located around said container means and removably secured to said exterior surface of said one end of said fastener.

9. The fastener of claim 8, comprising:

spring biasing means located in said cap means and seated against said cap means and said container means.

10. The fastener of claim 7, wherein:

said attaching means removably attaches said container means to the exterior surface of said head of said fastener.

11. The fastener of claim 1, wherein:

said attaching means removably attaches said container means to said head of said fastener.

12. A fastener comprising:

a shank having a head at one end and threads formed at the other end,

a shallow opening formed in one end of said fastener,

said opening having a depth less than the length of said head as measured along the longitudinal axis of said fastener,

an acoustic transducer located in said opening,

attaching means for removably attaching said transducer in said opening with said transducer acoustically coupled to said fastener,

said fastener being formed of metal with the portion of said fastener between said opening and the end of said fastener opposite said opening being of solid metal throughout.

13. The fastener of claim 12, wherein:

said transducer is located in said opening such that it may be used for pulse-echo measurements wherein when said transducer is pulsed, a transducer signal is generated which travels from said transducer through said fastener to said end of said fastener opposite said opening and back to said transducer at least once,

the distance between said transducer and said end of said fastener opposite said opening being equal to a major portion of the length of said fastener such that when said signal is generated it will travel through the entire gripping length of said fastener, including the portion of said shank next to said head, when traveling between said transducer and said end of said fastener opposite said opening.

14. The fastener of claims 12 or 13 wherein:

said opening is formed in said head only of said fastener.

15. The fastener of claim 12 or 13, wherein:

said opening is formed in said one end only of said fastener.

19. The fastener of claim 12, 13, 16, 17, or 18 wherein:

said attaching means comprises removable holding means located in said opening.

20. The fastener of claim 12, 13, 16, 17 or 18 wherein said attaching means comprises:

removable holding means located in said opening,

and

spring biasing means located in said opening and seated against said removable holding means for tightly holding said transducer in said opening in an acoustically coupled relationship with said fastener.

21. The fastener of claim 12, 13, 16, 17, or 18 wherein:

said acoustic transducer is acoustically coupled to said fastener to allow pulse-echo measurements to be obtained while said fastener is torqued in place with a wrench means,

said attaching means being separate from the wrench means whereby when the wrench means is removed from said fastener, said transducer remains attached to said fastener.

16. A fastener comprising:

a shank having a head at one end and threads formed at the other end,

a shallow opening formed in one end of said fastener,

an acoustic transducer located in said opening,

attaching means for removably attaching said transducer in said opening with said transducer acoustically coupled to said fastener such that it may be used for pulse-echo measurements wherein when said transducer is pulsed, a transducer signal is generated which travels from said transducer through said fastener to the end of said fastener opposite said transducer and back to said transducer at least once,

the distance between said transducer and said end of said fastener opposite said opening being equal to a major portion of the length of said fastener such that when said signal is generated it will travel through the entire gripping length of said fastener, including the portion of said shank next to said head, when traveling between said transducer and said end of said fastener opposite said opening,

the entire portion of said fastener between said opening and said end of said fastener opposite said opening being of solid metal throughout.

17. The fastener of claim 16, wherein:

said opening is formed in said head only of said fastener.

18. The fastener of claim 16, wherein:

said opening is formed in said one end only of said fastener.