Method of and apparatus for measuring automatically successive sections of an elongated material

• US 3,916,676 A
• Filed: 07/05/1972
• Issued: 11/04/1975
• Est. Priority Date: 07/05/1972
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: Howard John Flichman, James Alphus Jr. Hudson, Johnny William Levengood, Luther Miles Boggs
• Inventors: Boggs, Luther Miles, Flichman, Howard John, Hudson, James Alphus Jr., Levengood, Johnny William
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Beauchamp, John P.
• Application Number:
  US05/268,973
• Time in Patent Office: 1,217 Days
• Field of Search: 73/67.7,67.8R,67.8S,67.9
• US Class Current: 73/609
• CPC Class Codes: B29C 2948/92066 Time, e.g. start, termination, duration or interruption
• CPC Class Codes: B29C 2948/92114 Dimensions
• CPC Class Codes: B29C 2948/92152 Thickness
• CPC Class Codes: B29C 2948/92571 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/92609 Dimensions
• CPC Class Codes: B29C 2948/92923 Calibration, after-treatment or cooling zone
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/06 Rod-shaped
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: G01B 17/025 for measuring thickness of coating
• CPC Class Codes: G01R 31/59 while the cable continuously passes the testing apparatus, e.g. during manufacture

Abstract

In measuring ultrasonically automatically the thickness of a jacket of a cable being advanced along a predetermined path provisions are made for pulsing sequentially each one of four crystal transducers equiangularly deployed about the periphery of the advancing cable and spaced therefrom with at least the portions thereof facing the cable being immersed in a coupling medium. As each of the crystals is pulsed to emit ultrasonic waves to engage the cable, successive ones of first echo pulses from the outwardly facing surface of the jacket and of associated second echo pulses from the inwardly facing surface of the jacket are received and amplified. A receiver logic circuit is provided for causing the measurement of a time interval related to the time between the echo pulses and to the jacket thickness. The receiver logic circuit is provided with intelligence responsive to a sequence of valid first and second echo pulse pairs as determined by a consideration of amplitude and duration characteristics for the conversion of the measurement into a signal, the magnitude of which is proportional to the thickness of the cable jacket. Facilities are provided for displaying to an operator the thickness of the jacket and for converting the thicknesses into eccentricity measurements.

Claims

1. A method of monitoring ultrasonically an elongated member, which includes the steps of:

transmitting an ultrasonic pulse into an elongated member and then receiving a first echo pulse reflected from one surface of the member and then receiving an associated second echo pulse from an opposite surface of the member;

developing an on signal upon receipt of a qualifiying first echo pulse having at least a predetermineD minimum amplitude from the one surface of the member;

generating control signals to establish a predetermined time interval beginning with the receipt of a first echo pulse having the predetermined amplitude;

developing an off signal upon validation of a qualifying first echo pulse within the predetermined time interval and upon receipt of an associated second echo pulse having a predetermined minimum amplitude from the opposite surface of the material and occurring after the predetermined time interval with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the member and the receipt of the associated second echo pulse from the opposite surface of the member;

measuring the elapsed time between the on signal and the off signal; and

causing relative motion between the elongated member and the source of ultrasonic pulses.

2. A method of measuring automatically ultrasonically an elongated material, which includes the steps of:

advancing an elongated material;

transmitting an ultrasonic pulse into the material and then receiving a first echo pulse reflected from one surface of the material and then receiving an associated second echo pulse from an opposite surface of the material;

developing an on signal and an off signal upon the receipt of associated first and second echo pulses each having predetermined distinguishable characteristics which include amplitude and duration, with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the material and the receipt of the associated second echo pulse from the opposite surface of the material; and

converting the measured elapsed time into a signal, the magnitude of which is proportional to a parameter of the elongated material which is to be measured.

3. A method of measuring automatically ultrasonically the thickness of successive sections of elongated material, which includes the steps of:

advancing successive sections of an elongated material;

transmitting an ultrasonic pulse into the material and then receiving a first echo pulse reflected from one surface of the material and then receiving an associated second echo pulse from an opposite surface of the material;

developing automatically an on signal upon receipt of a qualifying first echo pulse having a predetermined minimum amplitude from one surface of the material;

generating control signals to establish first and second time intervals beginning with the receipt of a first echo pulse having the predetermined amplitude;

developing an off signal upon receipt of a qualifying first echo pulse which does not exceed the predetermined minimum amplitude after the first time interval and upon receipt of an associated second echo pulse having a predetermined minimum amplitude from the opposite surface of the material and occurring after the second predetermined time interval with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the material and the receipt of the associated second echo pulse from the opposite surface of the material;

the time duration between the on signal and the off signal being related to the thickness of the material; and

determining the thickness of the material in accordance with the elapsed time between the on signal and the off signal.

4. An apparatus for monitoring ultrasonically an elongated member, which includes:

means for transmitting an ultrasonic pulse into an elongated member and receiving a first echo pulse reflected from one surface of the member and receiving an associated second echo pulse from an opposite surface of the member;

means responsive to the receipt of a qualifying first echo pulse from the one surface of the membeR and having at least a predetermined minimum amplitude for developing an on signal;

means for generating control signals to establish a predetermined time interval beginning with the receipt of a first echo pulse having the predetermined minimum amplitude;

means responsive to the receipt of a qualifying first echo pulse which is validated within the predetermined time interval and to the receipt of an associated second echo pulse having a predetermined minimum amplitude from the opposite surface of the member and occurring after the predetermined time interval for developing an off signal with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the member and the receipt of the associated second echo pulse from the opposite surface of the member;

means for measuring the elapsed time between the on signal and the off signal; and

means for causing relative motion between the elongated member and at least the transmitting means.

5. An apparatus for monitoring ultrasonically successive sections of an elongated material, which includes:

means for advancing an elongated material;

means for transmitting an ultrasonic pulse into the material and then receiving a first echo pulse reflected from one surface of the material and then an associated second echo pulse from an opposite surface of the material;

means for developing an on signal and an off signal distinguishable from each other upon receipt of associated first and second echo pulses having predetermined distinguishable characteristics which include amplitude and duration, with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the material and the receipt of the associated second echo pulse from the opposite surface of the material; and

means for converting the measured elapsed time into a signal, the magnitude of which is proportional to a parameter of the elongated material which is to be measured.

6. An apparatus for measuring automatically ultrasonically successive sections of an elongated material, which includes:

means for advancing successive sections of an elongated material;

means spaced from the material under test for transmitting ultrasonic pulses into the material and for then receiving a first echo pulse reflected from one surface of the material and then receiving an associated second echo pulse from an opposite surface of the material;

means connected to the pulse transmitting and receiving means for developing an on signal and an off signal with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from one surface of the material and the receipt of the associated second echo pulse from the opposite surface of the material;

the signal developing means capable of developing an on signal and an off signal only upon the receipt by the transmitting and receiving means of a valid sequence of echo pulses including a first echo pulse which exceeds a predetermined minimum amplitude within a first preset time interval and a second echo pulse received after a second preset time interval;

means connected to the developing means and the transmitting and receiving means and rendered effective by the invalidity of at least one of the echo pulses for inhibiting the developing means; and

means connected to the pulse transmitting and receiving means and rendered effective upon receipt of on and off signals for indicating the elapsed time.

7. An apparatus for measuring distance in a medium having at least a first reflecting surface and a second reflecting surface, which includes:

means for cyclically transmitting ultrasonic pulses inside the medium through the first reflecting surface;

means for receiving the transmitted pulses and associated echo pulses received from the reflecting surfaces;

means connected to the receiving means and responsive to the receipt of associated echo pulses of predetermined minimum amplitudes during a predetermined time period for generating a signal having a duration proportional to the time interval which separates the echo pulses from the first and the second reflecting surfaces;

means connected to the generating means for measuring the time interval;

means in one state for operating the measuring means and when in another state for inhibiting the measuring means; and

means connected to the receiving means for amplitude detection of the pulses at a predetermined level and of the existance of a predetermined duration of the echo pulse from the first reflecting surface at the predetermined minimum amplitude level and of the occurence of at least a predetermined time interval from the beginning of the echo pulse from the first reflecting surface to the beginning of the echo pulse from the second reflecting surface to control the operating and the inhibiting means.

8. The apparatus of claim 7, wherein the means for controlling the operating and inhibiting means is responsive to a sequence of valid echo pulses from the first and second reflecting surfaces, a valid echo pulse from the first surface being one which exceeds a predetermined minimum amplitude for less than one time interval and a valid echo pulse from the second surface being one which exceeds a predetermined minimum amplitude beyond another time interval to operate the measuring means, and is responsive to the invalidity of at least one of the echo pulses for inhibiting the operation of the measuring means.

9. An apparatus for measuring automatically ultrasonically the thickness of successive sections of elongated material, which includes:

means for advancing successive sections of the elongated material;

means for tranmitting an ultrasonic pulse into the material and then receiving a first echo pulse reflected from one surface of the material and then receiving an associated second echo pulse from an opposite surface of the material;

means for developing automatically an on signal upon receipt of a first echo pulse of predetermined minimum amplitude from the one surface of the material;

means for generating control signals to establish first and second time intervals beginning with the receipt of a first echo pulse having the predetermined minimum amplitude;

means responsive to the receipt of a qualifying first echo pulse which does not exceed the predetermined minimum amplitude beyond the first time interval and to the receipt of an associated second echo pulse having a predetermined minimum amplitude from the opposite surface of the material and occurring after the second time interval for developing an off signal with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of the first echo pulse from the one surface of the material and the receipt of the associated second echo pulse from the opposite surface of the material, further, the time duration between the on signal and the off signal being related to the thickness of the material; and

means for determining the thickness of the material in accordance with the elapsed time between the on signal and the off signal.

10. An apparatus for measuring ultrasonically the thickness of successive sections of a cable jacket, which includes:

means for advancing successive sections of a cable;

means spaced from the cable for transmitting ultrasonic pulses into the cable and for receiving echo pulses therefrom;

means connected to the pulse transmitting and receiving means for developing an on signal and an off signal with the time duration between the on signal and the off signal being related to the elapsed time between the receipt of a first echo pulse after reflection from an outer surface of the jacket and the receipt of an associated sEcond echo pulse after reflection from an opposite inwardly facing surface of the cable jacket;

the signal developing means capable of developing an on signal and an off signal only upon the receipt by the transmitting and receiving means of the associated echo pulses during a predetermined time interval, each of the pulses having at least a predetermined minimum amplitude and the time during which the predetermined minimum amplitude of the first echo pulse occurs is not greater than a predetermined time;

means connected to the developing means and responsive only upon receipt of an associated second pulse having predetermined duration and amplitude characteristics for converting the elapsed time between the on signal and the off signal into a quantity indicative of the thickness of the jacket; and

means connected to the converting means for indicating the quantity indicative of the thickness of the jacket.

11. An apparatus for testing ultrasonically the thickness of successive sections of a jacket of a cable, which includes:

means for advancing successive sections of a cable;

a transducer spaced from the cable, the transducer and the cable being positioned in a coupling medium, the transducer having a line of focus which is transverse of the path of the cable;

means for exciting the transducer to emit pressure waves toward and then through the cable jacket, the engagement of the pressure waves with the outwardly facing surface of the cable causing a first echo pulse to be reflected therefrom and the engagement of the pressure wave with the inwardly facing surface of the jacket causing a second echo pulse associated with the first echo pulse to be reflected therefrom;

means for receiving and amplifying the echo pulses;

logic means connected to the amplifying means for validating a sequence of first and second echo pulses received during a predetermined time interval which have preestablished distinguishable amplitude and duration characteristics;

means rendered effective by the receipt of a valid first echo pulse and the receipt of a second echo pulse having a preset minimum amplitude for developing an on signal and an off signal with the time duration between the on signal and the off signal being the elapsed time between reflections from the outwardly and the inwardly facing surfaces of the cable and related to the thickness of the cable jacket;

means connected to the developing means for measuring the elapsed time;

means responsive to the validation of the first and the second echo pulses for causing the recordation of an output indicative of the jacket thickness; and

means for cyclically causing the exciting means to cause the transducer to emit pressure waves and for conditioning the logic means for another cycle of operation.

12. A method of measuring the thickness of an article having first and second surfaces bounding a material of known acoustical properties, which comprises the steps of:

establishing a medium having known acoustical characteristics contiguous with the first surface of an article;

generating a longitudinal wave in the medium directed toward the first surface, one part of the wave being reflected therefrom back through the medium as a first echo, the other part of the wave passing through the first surface and the article to the second surface, and a portion of the other part being reflected back through the article and the medium as a second echo;

generating a quantity proportional to the time interval between a first echo which exceeds a predetermined intensity within one time period and a second echo which occurs after a predetermined time period following the beginning of the first pulse to establish the thickness of the article; and

inhibiting the generation of quantity when either of the predetermined intensity or duration characteristics do not exist.

13. The method of claim 12, wherein the article is a cable jacket and the surfaces thereof define tHe thickness of the jacket.

14. An apparatus for measuring the thickness of an article having first and second surfaces bounding a material of known acoustical properties, which comprises:

means for establishing a medium having known acoustical characteristics contiguous with the first surface of an article;

means for generating a longitudinal wave in the medium directed toward the first surface, one part of the wave being reflected therefrom back through the medium as a first echo, the other part of the wave passing through the first surface and the article to the second surface, and a portion of the other part being reflected back through the article and the medium as a second echo;

means for generating a quantity proportional to the time interval between a first echo which exceeds a predetermined intensity within one time period and a second echo which occurs a predetermined time period following the beginning of the first pulse to establish the thickness of the article; and

means rendered effective when either of the predetermined intensity or duration characteristics do not exist for inhibiting the generation of any quantity.

15. The apparatus of claim 14, wherein the article is a cable jacket and the surfaces thereof define the thickness of the jacket.

16. The method of claim 3, wherein the elongated material is a jacket of a communications cable and the thickness of the jacket is measured.