Abstract: A compound counterbalance system for window sashes and the like, comprising: a biasing spring for easing operation of a window sash and the like, the biasing spring being movable at an inherently variable rate of force; a first biasing force transmission having a fixed rate of movement transmission part connected to the biasing spring and a variable rate of movement transmission part connected to the window sash and the like, the variable rate of movement transmission part having a variable rate of operation predetermined to automatically compensate for the variability of the biasing spring to provide substantial constancy of the biasing force throughout an operating range; and, a cable for interconnecting the biasing spring, the first biasing force transmission, and the window sash and the like, whereby loading forces on the first biasing force transmission are substantially constant throughout the operating range.

Abstract: A tip-lock shoe for a window sash and the like, comprising: a hollow body adapted to slidably travel in a track; a locking member disposed in the body and movable between a retracted position enabling the body to slide freely in the track and an extended position for engaging the track and preventing movement of the body; a first lock activating member disposed in the body for engaging the window sash and for urging the locking member from the retracted position to the extended position responsive to tilting of the window sash and the like; and, a second lock activating member disposed in the body for engaging a counterbalance system for supporting the body in the track and for urging the locking member from the retracted position to the extended position independently of the first lock activating member and automatically responsive to a loss of counterbalance force, whereby the window sash and the like can be slidably and tiltably operated in normal fashion when the counterbalance system is operating properl