Abstract: A pre-assembled, spring loaded, block and tackle window sash balance assembly is adapted for providing vertical support for a window sash running in an elongated, generally upright sash run having a generally C-shaped guide channel extending along its plow region. The assembly comprises a generally U-shaped housing for a block and tackle spring balance device. The assembly further includes spaced slide means which are discrete from the housing itself and which are slidably interengageable with the guide channel for removeably attaching the assembly to the sash run. Accordingly, the block and tackle balance assembly may be pre-assembled and then conveniently and efficiently attached to the sash run and supported in a position to provide spring balanced support for a window sash mounted in the sash run.

Abstract: A brake mechanism utilizes the tension of a spring acting upwardly and the weight of a window acting downwardly to produce a force couple for applying a frictional force to hold a window sash in a preselected position in a sash run. The mechanism is utilized in combination with a jamb liner defining an elongated sash run provided with a C-shaped guide channel in its plow region. The channel has co-planar, laterally spaced, flanges defining a longitudinally extending slot therebetween. A brake component has a pair of shoe portions disposed in the channel adjacent respective internal flange surfaces. The brake component rotates in the channel to move the shoe portions into frictional engagement with the internal flange surfaces. A columnar element rigid with the brake component extends through the slot and presents means disposed outside the channel for applying a torque to rotate the brake component inside the channel.