US Patent 11879281 Automatic window sash interlock

A window sash interlock includes a housing configured to mount to a side rail of a window sash. The housing includes a front face that substantially aligns with a surface of the side rail. A locking member is pivotably coupled to the housing about a pivot axis. The locking member is disposed at least partially within the housing and is movable between at least a locked position and an unlocked position. The locking member is biased so as to automatically return to the unlocked position, and in the unlocked position, the locking member at least partially extends from the front face of the housing.