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Compound counterbalance and winding systems with zero torque spirals

  • US 4,914,780 A
  • Filed: 08/02/1988
  • Issued: 04/10/1990
  • Est. Priority Date: 08/02/1988
  • Status: Expired due to Fees
First Claim
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1. A compound counterbalance system for a load such as a window sash and the like, comprising:

  • biasing means for easing operation of the load, the biasing means being characterized by an inherently variable rate of force;

    a first biasing force transmission means having a fixed rate of movement means connected to the biasing means and variable rate of movement means connected to the load, the variable rate of movement means having a variable rate of operation predetermined to automatically compensate for the variability of the biasing means to provide substantial constancy of the biasing force as applied to the load, throughout an operating range; and

    ,a second biasing force transmission means, connected between the first biasing force transmission means and the load, for increasing the operating range of the biasing means, the second biasing force transmission means including a block and tackle assembly.

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