Ultrasonic load indicating member
First Claim
1. A load indicating member comprising:
- a shank having a least one external groove; and
ultrasonic transducer means coupled to said load indicating member so that an ultrasonic wave is directed to said groove;
said external groove acting as an artificial reflector by providing at least one face for reflecting the ultrasonic wave generated by said ultrasonic transducer means back to said ultrasonic transducer means.
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Accused Products
Abstract
This invention relates to a load indicating member comprising a shank having at least one groove and an ultrasonic transducer coupled to a load indicating member so that an ultrasonic wave is directed to the groove. A surface can be formed adjacent to one longitudinal end of the shank and the ultrasonic transducer can be coupled to this surface. Further, the ultrasonic transducer can be coupled to this surface so that the ultrasonic wave is also directed to the other longitudinal end of the shank which is remote from the surface. The groove may be located on the shank at a predetermined distance from the surface for identification of the member. Moreover, the surface can have a recess, with the ultrasonic transducer being located in the recess. Advantageously, the groove can be an annular groove or the groove can be comprised of threads disposed on the shank. Also, the shank can have two or more annular grooves. These grooves can be located on the shank at a predetermined distance apart for identification of the load indicating member. Preferably, the ultrasonic transducer is a piezoelectric film transducer. Additionally, the preferred load indicating member is a fastener in accordance with the present invention.
66 Citations
36 Claims
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1. A load indicating member comprising:
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a shank having a least one external groove; and ultrasonic transducer means coupled to said load indicating member so that an ultrasonic wave is directed to said groove; said external groove acting as an artificial reflector by providing at least one face for reflecting the ultrasonic wave generated by said ultrasonic transducer means back to said ultrasonic transducer means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A fastener adapted for measuring strain in the fastener, said fastener comprising:
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a shank having a longitudinal axis and a predetermined longitudinal length, said shank being adapted to be subjected to longitudinal strain along said longitudinal axis; a head formed on one longitudinal-end of said shank, said head having a surface formed on the end portion of said head; at least one annular groove formed on said shank, said groove having at least one face for reflecting an ultrasonic wave to a piezoelectric film transducer means; said piezoelectric film transducer means being coupled with said end surface of said head so that an ultrasonic wave is directed towards said annular groove. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A fastener adapted for measuring strain in the fastener, said fastener comprising:
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a shank having a longitudinal axis and a predetermined longitudinal length, said shank being adapted to be subjected to longitudinal strain along said longitudinal axis; a head formed on one longitudinal end of said shank, said head having a surface formed on the end portion of said head; threads formed on said shank, wherein at least one of said threads has a face for reflecting an ultrasonic wave to a piezoelectric film transducer means; said piezoelectric film transducer means being coupled with said end surface of said head, said thread face being generally parallel to a portion of said end surface of said head to which said transducer means is coupled to that an ultrasonic wave is directed towards said thread face and the ultrasonic wave is reflected back to said transducer means. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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- 29. A method of measuring strain in a load indicating member of the type comprised of a shank having at least one groove and an ultrasonic transducer means coupled to said load indicating member so that an ultrasonic wave is directed to said groove, said method comprising generating an ultrasonic signal from said ultrasonic transducer means so that said signal travels through said load indicating member to said groove and reflects back to said ultrasonic transducer means at least once, thereby providing measurements indicative of strain on said load indicating member.
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33. A load indicating member comprising:
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a shank having at least one annular groove; and ultrasonic transducer means coupled to said load indicating member so that an ultrasonic wave is directed to said groove. - View Dependent Claims (34, 35)
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36. A fastener adapted for measuring strain in the fastener, said fastener comprising:
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a shank having a longitudinal axis and a predetermined longitudinal length, said shank being adapted to be subjected to longitudinal strain along said longitudinal axis; a head formed on one longitudinal end of said shank, said head having a surface formed on the end portion of said head; threads formed on said shank, wherein at least one of said threads has a face for reflecting an ultrasonic wave to a piezoelectric film transducer means; said piezoelectric film transducer means being coupled with said end surface of said head so that an ultrasonic wave is directed towards said threads; wherein said end surface of said head forms a helical cone in axial alignment with said shank wherein the pitch of said end surface is equal to the pitch of said threads.
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Specification