US Patent 6840011 Window panel balance apparatus and method

A window having a window panel that slides in a frame and at least one balancer that is secured to the window panel is disclosed. The window is of the tiltable hung type having a vertical operating position in which the balancer slides with the window panel in the frame and a tilted position in which the balancer remains secured to the window panel. The balancer includes an extensible member having a first end operatively coupled to the balancer and a second end operatively coupled to a frame so that the balancer can exert a force on the window panel to assist against the force of gravity when the window panel is in the vertical operating position. A method of constructing a tiltable hung window with a balancer secured to the window panel is also disclosed.