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Covert alarm and locator apparatus for miners

  • US 7,724,132 B1
  • Filed: 09/04/2007
  • Issued: 05/25/2010
  • Est. Priority Date: 11/01/2004
  • Status: Expired due to Fees
First Claim
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1. An article of footwear comprising:

  • (a) means for periodically determining location data of said article of footwear based on the location of fixed locator devices having known positions comprising a transponder which derives its position by transmitting a signal to a locator device, which locator device sends a return encoded with an identification for said locator device, whereby said means for periodically determining the location of said article of footwear is able to derive its location, as a known distance from said locator device; and

    (b) means for the selective transmission of an alarm signal encoded with said location data, said transmitted signal having a frequency and modulation selected to minimize the attenuation thereof through underground materials, and said alarm signal only being transmitted upon the selective activation by the wearer of said footwear.

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