US4899591A — Ultrasonic load indicating member, apparatus and …

Claim 1

Independent Claim 138 words

A method of making a load indicating fastener from a fastener having a head and a shank extending from the head, said shank being subjected to elastic deformation when stressed longitudinally such that one portion thereof moves relative to another portion thereof, said method comprising the steps of: forming a first flat surface on said head and a location remote from said shank, said first flat surface being normal to the longitudinal axis of said shank; forming a piezoelectric sensor by applying a first and a second electrode means to opposite faces of a piezoelectric disk; and permanently, acoustically, and mechanically interconnecting said piezoelectric sensor to said head of said fastener such as to electrically interconnect a first electrode of said piezoelectric sensor with said head and, further, such as to isolate said second electrode from said head.

Claim 2

Independent Claim 138 words

A method of making a load indicating fastener from a fastener having a head and a shank extending from the head, said shank being subjected to elastic deformation when stressed longitudinally such that one portion thereof moves relative to another portion thereof, said method comprising the steps of: forming a first flat surface on said head and a location remote from said shank, said first flat surface being normal to the longitudinal axis of said shank; forming a piezoelectric sensor by applying a first and a second electrode means to opposite faces of a piezoelectric disk; and permanently, acoustically, and mechanically interconnecting said piezoelectric sensor to said head of said fastener such as to electrically interconnect a first electrode of said piezoelectric sensor with said head and, further, such as to isolate said second electrode from said head.

Claim 3

Dependent Claim 20 words

The method of claim 1 wherein said flat surface has a surface finish of approximately more than 250 micro inches.

Claim 4

Dependent Claim 12 words

The load indicating member made according to the method of claim 1.

Claim 5

Dependent Claim 17 words

The method of claim 1 wherein said electrodes are formed by vapor deposition, electrodeposition or metallic painting.

Claim 6

Dependent Claim 17 words

The method of claim 1 wherein said first electrode means comprises a electrically and acoustically conductive adhesive.

Claim 7

Dependent Claim 98 words

A load measuring device for use in conjunction with a load indicating member having a shank, a first flat surface formed adjacent one longitudinal end of said shank, and a piezoelectric transducer secured to said first flat surface, said load measuring device comprising: first contact means selectively engageable with said load indicating member; second contact means selectively engageable with said piezoelectric transducer; and measurement means responsive to the electronic differential between said first and second contact means such as to provide a measurement of a tensile load dependant characteristic of said shank when said shank is stressed longitudinally.

Claim 8

Dependent Claim 98 words

A load measuring device for use in conjunction with a load indicating member having a shank, a first flat surface formed adjacent one longitudinal end of said shank, and a piezoelectric transducer secured to said first flat surface, said load measuring device comprising: first contact means selectively engageable with said load indicating member; second contact means selectively engageable with said piezoelectric transducer; and measurement means responsive to the electronic differential between said first and second contact means such as to provide a measurement of a tensile load dependant characteristic of said shank when said shank is stressed longitudinally.

Claim 9

Dependent Claim 67 words

The load measuring device of claim 6 wherein said load indicating member further comprises first engagement means formed at one end of said shank, said load measuring device further comprising: second engagement means selectively engageable with said first engagement means when said load measuring device is used in conjunction with said load indicating member such as to axially position said contact means relative to said piezoelectric transducer.

Claim 10

Dependent Claim 18 words

The load measuring device of claim 7 wherein said second engagement means comprises said first electrical contact means.

Claim 11

Dependent Claim 73 words

The load measuring device of claim 8 wherein said indicating member comprises a fastener having a head formed at one end of said shank, and said first engagement means comprises tool engagement means formed on said head; and further wherein: said second engagement means of said load measuring device further comprises tool means selectively engageable with said tool engagement means such that said fastener is selectively rotated by rotation of said tool means.

Claim 12

Dependent Claim 45 words

The load measuring device of claim 9 further comprising: interconnection means for interconnecting said tool means with wrenching means such as to selectively impart a rotational motion to said fastener to install and to remove said fastener while measuring said tensile load dependant characteristic thereof.

Claim 13

Dependent Claim 42 words

The load measuring device of claim 10 wherein said measurement means provides an output signal indicative of the elongation of said shank and further wherein said load measuring device further comprises: commutator means for communicating said output signal to said wrenching means.

Claim 14

Dependent Claim 20 words

The load measuring device of claim 10 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 15

Dependent Claim 43 words

The load measuring device of claim 10 wherein said measurement means detects a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combines said first and second signal to determine said tensile load dependant characteristic.

Claim 16

Dependent Claim 40 words

The load measuring device of claim 13 wherein said measurement means applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Claim 17

Dependent Claim 40 words

The load measuring device of claim 10 wherein said measurement means applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Claim 18

Dependent Claim 20 words

The load measuring device of claim 6 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 19

Dependent Claim 43 words

The load measuring device of claim 16 wherein said measurement means detects a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combines said first and second signal to determine said tensile load dependant characteristic.

Claim 20

Dependent Claim 40 words

The load measuring device of claim 17 wherein said measurement means applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Claim 21

Dependent Claim 43 words

The load measuring device of claim 6 wherein said measurement means detects a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combines said first and second signal to determine said tensile load dependant characteristic.

Claim 22

Dependent Claim 40 words

The load measuring device of claim 6 wherein said measurement means applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Claim 23

Dependent Claim 20 words

The load measuring device of claim 20 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 24

Independent Claim 162 words

A method of tightening a load indicating fastener of the type having a shank subject to elastic deformation when stressed longitudinally, a head formed at one longitudinal end of said load indicating fastener, a first flat surface formed adjacent said head, tool engagement means formed on said head adjacent said first flat surface, piezoelectric sensor means permanently mounted on said first flat surface, and a second flat surface formed at the other longitudinal end of said shank, said method comprising the steps of: engaging a tightening tool with said tool engagement means; engaging contact means with said piezoelectric sensor; operating said tightening tool to tighten said load indicating fasteners; and measuring a signal representative of the time of flight of an ultrasonic wave along said shank by monitoring the differential electronic signal between said tool engagement means and said contact means such as to provide a continuous measurement of the tensile load of said shank during the operation of said tightening tool.

Claim 25

Independent Claim 162 words

A method of tightening a load indicating fastener of the type having a shank subject to elastic deformation when stressed longitudinally, a head formed at one longitudinal end of said load indicating fastener, a first flat surface formed adjacent said head, tool engagement means formed on said head adjacent said first flat surface, piezoelectric sensor means permanently mounted on said first flat surface, and a second flat surface formed at the other longitudinal end of said shank, said method comprising the steps of: engaging a tightening tool with said tool engagement means; engaging contact means with said piezoelectric sensor; operating said tightening tool to tighten said load indicating fasteners; and measuring a signal representative of the time of flight of an ultrasonic wave along said shank by monitoring the differential electronic signal between said tool engagement means and said contact means such as to provide a continuous measurement of the tensile load of said shank during the operation of said tightening tool.

Claim 26

Dependent Claim 58 words

The method of claim 22 wherein said step of operating said tightening tool further comprises rotating said tightening tool until the occurrence of a condition measured by said tightening tool indicative of a proper joint, said method further comprising the step of: verifying the existence of a proper joint using said measurement of said tensile load dependant characteristic.

Claim 27

Dependent Claim 33 words

The method of claim 22 further comprising the step of: ceasing operation of said tightening tool when said measuring step indicates that a predetermined level of said tensile load dependant characteristic is measured.

Claim 28

Dependent Claim 18 words

The method of claim 24 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 29

Dependent Claim 46 words

The method of claim 24 wherein said step of measuring a signal further comprises detecting a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combining said first and second signal to determine said tensile load dependant characteristic.

Claim 30

Dependent Claim 41 words

The method of claim 24 wherein said steps of measuring a signal applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Claim 31

Dependent Claim 18 words

The method of claim 27 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 32

Dependent Claim 46 words

The method of claim 28 wherein said step of measuring a signal further comprises detecting a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combining said first and second signal to determine said tensile load dependant characteristic.

Claim 33

Dependent Claim 35 words

The method of claim 22 wherein said two engaging steps occur simultaneously, said tool engagement means being fixedly interconnected with said tightening tool and said contact means being reciprocably interconnected with said tool engagement means.

Claim 34

Dependent Claim 18 words

The method of claim 22 wherein said tensile load dependant characteristic comprises stress, elongation, strain or tensile force.

Claim 35

Dependent Claim 46 words

The method of claim 22 wherein said step of measuring a signal further comprises detecting a first signal indicative of a transverse wave and a second signal indicative of an longitudinal wave and combining said first and second signal to determine said tensile load dependant characteristic.

Claim 36

Dependent Claim 41 words

The method of claim 22 wherein said step of measuring a signal applies the direct timing, indirect timing, double pulsing, clock interpolation, fundamental frequency detection, acoustic impedance, harmonic resonance detection, or phase detection technique to determine said tensile load dependant characteristic.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-02-12	1993-08-14	1994-02-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-02-12	1997-08-14	1998-02-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-02-12	2001-08-14	2002-02-13	$7700.00	Window Closed / Lapsed

Ultrasonic load indicating member, apparatus and method

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