Flaw detecting apparatus for railroad rails and the like

• US 4,004,455 A
• Filed: 05/23/1975
• Issued: 01/25/1977
• Est. Priority Date: 05/23/1975
• Status: Expired due to Term

• Current Assignee: Teleweld Incorporated
• Original Assignee: Teleweld Incorporated
• Inventors: Henderson, C. Glenn, McKee, Chester W.
• Primary Examiner(s): Gill, James J.
• Assistant Examiner(s): Kreitman, Stephen A.
• Application Number:
  US05/580,158
• Time in Patent Office: 613 Days
• Field of Search: 73/67.9, 73/67.8 R, 73/67.8 S, 73/67.7, 73/67.5 R, 73/71.5 US
• US Class Current: 73/615
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2623 Rails; Railroads
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material

Abstract

Apparatus is disclosed for use in detecting flaws in the bolt hole area of railroad rails and the like, and is adapted to detect and record the location of an oversized hole indicating a crack or the like. The apparatus utilizes an ultrasonic transducer detector which is actuated by a free running pulse generator, and includes a counter and associated circuitry which compares the time required for the pulse to travel through the rail with a preset time and, if the rail has no flaw, causes an output to be produced that is used to reset the counter. The counter is also triggered by a speed related pulse generator that effectively measures the distance traveled by the car along the rail and thereby measures the size of the flaw. A flaw exceeding a predetermined size which is approximately the diameter of bolt holes, will trigger an alarm and cause a recorder to be activated.

Claims

1. Apparatus for moving along a railroad rail to test and detect flaws in the railroad rail, comprising:

means for transmitting ultrasonic signals into the rail and for receiving associated echo signals reflected from within the rail;

means operably connected to said transmitting means for producing a trigger signal that causes said transmitting means to transmit an ultrasonic signal, said trigger signal being generated independently of the movement of the apparatus along the rail,

means operably connected to said trigger signal producing means and said transmitting and receiving means for producing an electrical reset signal only in response to an echo signal being received at a predetermined time following the transmitting of an ultrasonic signal, said predetermined time corresponding to the time at which a transmitted ultrasonic signal which has traveled to and reflected from the bottom of the rail will have returned to the transmitting and receiving means, whereby a reset signal is generated only when an echo signal is received from the bottom of a rail;

means for producing electrical pulses at predetermined intervals of distance as said apparatus moves along the rail;

means connected to said pulse producing means and said reset signal producing means for counting said pulses, said counting means being reset in response to a reset signal being received; and

means sensing the state of said counting means for producing an indication of a flaw when said count exceeds a predetermined value.

2. Apparatus as defined in claim 1 wherein said reset signal producing means includes means for adjusting said predetermined time to accommodate the thickness of the rail or the like being tested.

5. Apparatus as defined in claim 1 wherein said indication producing means comprises comparator means for comparing the count from the counting means with a preset count appearing on a variable count set switch, said comparator means being adapted to produce an output signal when the count of said counting means reaches the count on the preset switches.

6. Apparatus as defined in claim 1 wherein said electrical pulse producing means is adapted to produce an electrical pulse for each distance of travel of about one-sixteenth inch of said apparatus along the rail.

3. Apparatus for testing and detecting flaws in a railroad rail or the like, comprising:

means for transmitting ultrasonic signals into the rail and for receiving associated echo signals reflected from within the rail;

means operably connected to said transmitting means for producing a trigger signal that causes said transmitting means to transmit an ultrasonic signal;

means operably connected to said trigger signal producing means and said transmitting and receiving means for producing an electrical reset signal only in response to an echo signal being received at a predetermined time following the transmitting of an ultrasonic signal, said predetermined time corresponding to the time at which a transmitted ultrasonic signal which has traveled to and reflected from the bottom of the rail will have returned to the transmitting and receiving means, whereby a reset signal is generated only when an echo signal is received from the bottom of the rail, and including means for adjusting said predetermined time to accommodate the thickness of the rail or the like being tested, said reset signal producing means comprising an adjustable electrical delay circuit having its input connected to the output of said trigger signal producing means and its output connected to the input of a NAND gate and said transmitting means being connected to the other input of said NAND gate whereby simultaneous occurrences of signals at the input to said NAND gate will produce a reset signal at the output thereof;

means for producing electrical pulses at predetermined intervals of distance as said apparatus moves along the rail;

means connected to said pulse producing means and said reset signal producing means for counting said pulses, said counting means being reset in response to a reset signal being received; and

means sensing the state of said counting means for producing an indication of a flaw when said count exceeds a predetermined value.

4. Apparatus as defined in claim 3 further including amplification and wave shaping means interconnected between said transmitting means and said NAND gate input.

7. Apparatus for testing and detecting flaws in a railroad rail or the like, comprising:

transducer means adapted to transmit ultrasonic signals into the rail and receive the echo signals reflected by the rail;

trigger means for activating said transmitting means, said trigger means operating independently of the movement of the apparatus along the rail;

gate means operably connected to said transmitting means and to said trigger means for producing a reset signal in the event the echo signal is received after a predetermined time delay;

means for producing a pulse for each interval of distance of rail over which the apparatus moves;

counting means connected to said pulse producing means for counting said pulses, said gate means being connected to said counting means and resetting said counting means whenever a reset signal is generated thereby; and

means connected to said counting means for producing an electrical indicator signal in the event the count reaches a predetermined value.

8. Apparatus as defined in claim 7 including an adjustable delay circuit adapted to change the predetermined time delay to accommodate rails of different heights.

9. Apparatus as defined in claim 8 wherein said delay circuit is preset so that said predetermined time delay approximates the time required for an ultrasonic signal to be transmitted and received through the entire height of the rail.