Crack detector

Claim 2

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point on its surface, said vibration transducer means including a contacting element to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, and means responsive to said vibration transducer means to detect and measure the returned energy in comparison with the amount of energy imparted to the article.

Claim 3

The crack detector device of claim 1, further characterized by said means to detect and measure the returned energy including means to compare the ascending slope of a curve depicting energy to the article and the descending slope of said curve depicting energy returned from the article whereby a cracked article produces a lesser slope than a sound article and a sound article produces a more symmetrical curve.

Claim 4

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point on its surface, said vibration transducer means including a contacting element to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, and means responsive to said vibration transducer means to detect and measure the returned energy, said means to detect and measure the returned energy having means to detect a pulse and compare the width of said pulse with a predetermined pulse width whereby a cracked article produces a wider pulse than a sound article.

Claim 5

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point on its surface, said vibration transducer means including a contacting element to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, and means responsive to said vibration transducer means to detect and measure the returned energy, said means to detect and measure the returned energy having means to detect a pulse and compare the width of said pulse with a predetermined pulse width whereby a cracked article produces a wider pulse than a sound article.

Claim 6

The crack detector device of claim 1, further characterized by said vibration transducer means including a series of said contacting elements to contact the article under test as the article rolls over said contacting elements presenting different portions of its surface to successive elements.

Claim 7

The crack detector device of claim 4, further characterized by protective sheet covering having openings therein for said series of contact points to protrude therethrough.

Claim 8

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point of its surface, said vibration transducer means including a series of contacting elements to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, contacting the article under test as the article rolls over said contacting elements presenting different portions of its surface to successive elements, said means to detect and measure the returned energy being pulse width discriminating means to detect a pulse and compare the width of said pulse with a predetermined pulse width whereby a cracked article produces a wider pulse than a sound article, said pulse width discriminating means being responsive only to the first pulse of a pulse train produced from each of the successive contacts.

Claim 9

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point of its surface, said vibration transducer means including a series of contacting elements to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, contacting the article under test as the article rolls over said contacting elements presenting different portions of its surface to successive elements, said means to detect and measure the returned energy being pulse width discriminating means to detect a pulse and compare the width of said pulse with a predetermined pulse width whereby a cracked article produces a wider pulse than a sound article, said pulse width discriminating means being responsive only to the first pulse of a pulse train produced from each of the successive contacts.

Claim 10

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point on its surface, said vibration transducer means including a series of contacting elements to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, contacting the article under test as the article rolls over said contacting elements presenting different portions of its surface to successive elements, each of said series of contacting elements operatively attached to a piezoelectric crystal, amplifying means connected to said piezoelectric crystals, clipping means connected to said amplifying means, pulse width discriminator means connected to said clipping means.

Claim 11

A crack detector device comprising a vibration transducer means positioned to contact an article under test on at least one point on its surface, said vibration transducer means including a series of contacting elements to impart energy to the article under test by contacting it during relative motion of the article and said vibration transducer means and to receive energy returned from the article, contacting the article under test as the article rolls over said contacting elements presenting different portions of its surface to successive elements, each of said series of contacting elements operatively attached to a piezoelectric crystal, amplifying means connected to said piezoelectric crystals, clipping means connected to said amplifying means, pulse width discriminator means connected to said clipping means.

Claim 12

The crack detector device of claim 7 further characterized by means to reject cracked articles after they have rolled over said series of contact points including continuous tape wound on means for moving said tape, read-in means connected to said pulse width discriminator means, gating means for rejectIng cracked articles, read-out means connected to said gating means spaced from said read-in means a predetermined distance in relation to the timed movement of said tape to coincide the reading of said read-out means with the arrival of the article at said gating means.

Claim 13

The crack detector device of claim 4, further characterized by each of said series of contact points operatively attached to a piezoelectric crystal having an output therefrom, differentiating network means connected to said crystal outputs to determine the slopes of curves depicting energy imparted to the articles and energy returned from the articles, inverting amplifier means connected to said differentiating network means, peak reader means connected to said inverting amplifier means and said differentiating network means, comparator means connected to each of said peak reader means, and integrating circuit means connected to said comparator means.

Claim 18

The method of detecting cracks of claim 10, further comprising said step of receiving including detecting the energy imparted to the article and the energy received from the article in the form of a curve having ascending and descending slopes, and said step of comparing the amount of energy involving comparison of ascending and descending slopes whereby a cracked article produces a lesser slope than a sound article and further departs from a symmetry of ascending and descending slopes.