Boots – shoes – and leggings
Patent
1989-12-19
1991-04-23
Lall, Parshotam S.
Boots, shoes, and leggings
364507, 73587, G01N 2904
Patent
active
050105035
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus for nondestructive inspection and testing of articles, and more particularly it relates to apparatus for acoustic-emission inspection of articles.
2. Description of the Related Art
There is widely known an apparatus for acoustic-emission determination of the coordinates of a developing crack in an article, comprising a plurality of channels each including a serial connection of a transducer of acoustic emission signals, positionable on an article, under inspection, and an amplifier of signals of acoustic emission. The outputs of the amplifiers of acoustic emission signals of all channels are connected to the first inputs of an encoder. Connected to the first outputs of the encoder are the first inputs of respective shift registers in a number equalling the number of the channels. The outputs of all shift registers are connected to the inputs of the first OR gate and to the first input of an electronic computing unit having its output connected to the input of a registration unit. The output of the first OR gate is connected to the respective first inputs of the first and second flip-flops. The first output of the first flip-flop is connected to the second input of the encoder. The second output of the first flip-flop is connected to the first input of a counter. The apparatus further comprises a second OR gate of which the first input is connected to the second output of the electronic computing unit, the second input is connected to the first output of the counter, and the output is connected to the second inputs of the respective shift registers, to the second input of the first flip-flop, and to the first input of the third OR gate. The second input of the third OR gate is connected to the third output of the electronic computing unit. The output of the third OR gate is connected to the second input of the second flip-flop.
The apparatus also comprises a series connection of a clock pulse generator and an AND gate, the second input of the electronic computing unit being connected to the output of the second flip-flop, as is the second input of the AND gate, and the third input of the electronic computing unit being connected to the digit outputs of the counter. The third inputs of the shift registers are connected along with the second input of the counter, to the output of the AND gate.
When a developing crack evolves in the article, a signal comes to the transducer of acoustic emission signals, and the code of the channel which has been the first to receive the acoustic emission signal is written in the lower-order digits of the shift registers. Then this code is shifted in the shift registers through the number of digit positions corresponding to the time interval passing before the instant of reception of an acoustic emission signal by another channel, whose code is written in the lower-order digits of the shift registers.
The appearance of the code of the first-mentioned channel at the output of the registers triggers the process of data transfer to the electronic computing unit. The counter counts the number of the digit positions between successive codes written in the shift registers, thus determining the time intervals between the instants of reception of the acoustic emission signals in the respective channels. However, for the apparatus to ensure proper functioning of this data-reading mode, the encoder is inhibited, so that reception of new information is also inhibited. This amounts to a high probability of useful signals of acoustic emission being missed by the apparatus, which significantly impairs the reliability and credibility of the inspection of an article.
Also widely known is an apparatus for determining from acoustic emission signals the coordinates of a crack developing in an article, comprising a plurality of channels each including a series connection of a transducer of acoustic emission signals positionable on an article under inspection and an amplifier of electric signals having
REFERENCES:
patent: 4459851 (1984-07-01), Crostack
patent: 4562736 (1986-01-01), Iwasaki
patent: 4609994 (1986-02-01), Bassim et al.
patent: 4641526 (1987-02-01), Izumi et al.
patent: 4644482 (1987-02-01), Juanarena
Gorlitsyn Nikolai V.
Khromyak Nikolai T.
Mezhuev Nikolai N.
Mezintsev Evgeny D.
Nedoseka Anatoly Y.
Institut Elektrosvarki Imeni E.O. Patona Akademii Nauk Ukrainsko
Lall Parshotam S.
Melnick S. A.
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