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Methods for operating window covers

DC
  • US 8,887,788 B2
  • Filed: 06/14/2013
  • Issued: 11/18/2014
  • Est. Priority Date: 11/04/1997
  • Status: Expired due to Term
First Claim
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1. A window cover system, comprising:

  • an extendable window cover, the window cover having a pair of lift cords;

    a lift cord pulley shaft coupled to a pair of spaced apart lift cord pulleys, wherein the lift cords are configured to wind and unwind around the lift cord pulleys when the lift cord pulley shaft is rotated;

    a spring drive unit having a beveled gear system with a first gear that is spring biased to resist rotation of the first gear in one direction of rotation, and a second gear meshed with the first gear, wherein the lift cord pulley shaft extends through the second gear and is configured to rotate therewith, and wherein the spring drive unit is positioned between the two lift pulleys.

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