Self-closing fire door

  • US 5,355,927 A
  • Filed: 12/17/1992
  • Issued: 10/18/1994
  • Est. Priority Date: 12/17/1992
  • Status: Expired due to Term
First Claim
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1. A door comprising:

  • a curtain including a plurality of interconnected relatively pivotal slats aligned in a single direction;

    means for guiding movement of said curtain between an opened position and a closed position;

    an outer tube operatively connected to a first end of said curtain for winding said curtain thereabout as said curtain is moved to its opened position and for unwinding said curtain as said curtain is moved to its closed position;

    an inner shaft;

    resilient tensioning means disposed between said outer tube and said first inner shaft, a first portion of said resilient tensioning means being operatively connected to said outer tube and a second portion of said resilient tensioning means being operatively connected to said inner shaft, wherein the tension of said resilient tensioning means is maintained substantially constant irrespective of the degree of opening or closing of said curtain to thereby tightly wind said curtain around said outer tube;

    regulating means for regulating the speed of said curtain comprising a speed reduction means for reducing a rotational speed, an input shaft connected to said speed reduction means, an output shaft connected to said speed reduction means, said speed reduction means for reducing the rotational speed of said output shaft relative to said input shaft, a governor mounted on said input shaft for limiting the rotational speed thereof thereby limiting the rotational speed of the said output shaft;

    a self-closing mechanism operatively connected to said curtain for moving said curtain to its closed position, said self-closing mechanism including a second inner shaft, a second outer tube and a second resilient tensioning means, wherein a first portion of said second resilient tensioning means is operatively connected to said second inner shaft and a second portion of said second resilient tensioning means is operatively connected to said second outer tube, wherein said second outer tube is operatively connected to said output shaft by said connecting means and is operatively connected to said curtain, wherein said second inner shaft is maintained in a fixed position, and wherein said second resilient tensioning means is adapted for storing energy when said curtain is moved to its open position;

    connecting means for operatively connecting said output shaft to said self closing mechanism and said inner shaft;

    a brake for preventing rotation of said output shaft thereby blocking movement of said self-closing mechanism; and

    releasing means for releasing said brake to free said output shaft for rotation, thereby enabling said movable means to release energy stored thereby and urge said curtain to its closed position.

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