ABOUT SASH WINDOWS
Sash windows have been used since the 17th century. They are now enjoying popularity once again; its design is simple and functional.
Most traditional sash windows are designed with box frames with pulleys set along with weights to counterbalance the sashes.
The weights are a vital component for a smooth operating window and are attached to the window panel by a sash cord, this runs over a pulley at the top of the frame.