Blasting machine

History

The first satisfactory magnetic induction blasting machine was constructed in 1878 by Henry Julius Smith of Mountain View, New Jersey. Its mechanism consisted of a T-handle that was pushed down; the lower end of the handle was a rack that drove a pinion, which in turn drove a high-voltage magneto, which generated the high voltage that is required to detonate the blasting cap.

Design

A typical "capacitive discharge" blasting machine works by charging a capacitor from a battery, then discharging the capacitor through an external circuit, called the firing line, to fire the blasting cap. While the machine is idle, an "internal shunt" is connected across the output terminals so that any stray voltages induced in the external circuit, for example by nearby radio transmitters, are harmlessly short-circuited without triggering the blasting cap. The machines also typically include an "abort" feature to discharge the internal capacitor without firing the cap.

In popular culture

Despite the older "T-Handle" design no longer being used, this design of blasting machine is most closely associated with Looney Tunes, and the character Wile E. Coyote, due to his penchant for attempting to use explosive materials to capture or incapacitate the Road Runner, often ending in disaster for the Coyote as the explosive either backfires, the machine does not work properly, or the T-handle gets stuck.

References

References

1. Smith, H. Julius, [http://pdfpiw.uspto.gov/.piw?Docid=00201296&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0201,296.PN.%2526OS%3DPN%2F0201,296%2526RS%3DPN%2F0201,296&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page "Improvement in magneto-electric machines"], U.S. Patent no. 201,296 (January 17, 1878)
2. Smith, H. Julius, [http://pdfpiw.uspto.gov/.piw?Docid=00353827&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect2%3DPTO1%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%2Fnetahtml%2FPTO%2Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526d%3DPALL%2526S1%3D0353827.PN.%2526OS%3DPN%2F353827%2526RS%3DPN%2F353827&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page "Dynamo-electric igniting machine"], U.S. Patent no. 353,827 (December 7, 1886)
3. Smith, Henry Julius, [http://pdfpiw.uspto.gov/.piw?Docid=00534289&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect2%3DPTO1%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%2Fnetahtml%2FPTO%2Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526d%3DPALL%2526S1%3D0534289.PN.%2526OS%3DPN%2F534289%2526RS%3DPN%2F534289&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page "Art of blasting"], U.S. Patent no. 534,289 (February 19, 1895)
4. Krehl, Peter O. K., ''History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference'' (Berlin, Germany: Springer, 2009), p. 365.
5. [http://www.blasterstool.com/buzzboxbb-30blastingmachine.aspx "Buzz Box: BB-30 Blasting Machine"] {{webarchive. link. (June 23, 2012 , Blasters Tool & Supply Company, accessed 2012-07-09)