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Signaling device for detecting the presence of an object

  • US 8,134,473 B2
  • Filed: 04/10/2009
  • Issued: 03/13/2012
  • Est. Priority Date: 04/10/2008
  • Status: Active Grant
First Claim
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1. A sheet switch for use in detecting a body or object with respect to a bed, said switch comprising:

  • a pair of planar sheets having facing conductive elements;

    said pair of planar sheets are separated by one or more separators;

    said facing conductive elements contacting one another under force and closing an associated circuit so as to provide an electrical signal indicative of said sheet switch changing electrical states;

    said pair of planar sheets comprise a first layer sheet and a second layer sheet;

    said facing conductive elements of said first layer sheet comprise a first conductor and a second conductor physically spaced apart from said first conductor;

    said facing conductive elements of said second layer sheet comprise a single conductive path;

    when said facing conductive elements are separated by said separators, an electrical potential can be applied at a first level between said first conductor and said second conductor;

    when said facing conductive elements contact one another under said force, said single conductive path of said second layer sheet will conductively contact both said first conductor and said second conductor of said first layer sheet;

    when said single conductive path conductively contacts said first conductor and said second conductor, said electrical potential between said first and said second conductors will change from said first level to a second level, measurably different from said first level;

    when said electrical potential across said first conductor and said second conductor has changed to said second level, said sheet switch can be characterized as being in a closed state;

    said first conductor is in the form of a pattern of first individual conductor lines spaced apart in a substantially parallel configuration, with a common conductor line conductively interconnecting together the first individual conductor lines;

    said second conductor is in the form of a pattern of second individual conductor lines spaced apart in a substantially parallel configuration, with a common conductor line conductively interconnecting together the second individual conductor lines of said second conductor; and

    said first individual conductor lines of said first conductor run substantially parallel to said second individual conductor lines of said second conductor, with said individual conductor lines of said first and second conductors being interspaced on said first layer.

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