Patent ID: 7265672

Claim:
A single magnetic sensor assembly in combination with a double hung window assembly comprised of a frame secured to a building wall, said frame having an open rectangular structure surrounding and supporting both a lower sash and an upper sash adapted for sliding movement from closed positions along respective vertical paths of travel, said frame having a head at an upper side of the window assembly, two jambs forming opposite sides of the window assembly, and a sill extending between the jambs to form a lower side of the window, said lower sash occupying a lower portion of the window area adjacent the sill and comprising a generally rectangular sash frame and a glass section fixed in the sash frame, said upper sash occupying an upper portion of the widow area adjacent the head and comprising a generally rectangular sash frame and a glass section fixed in the upper sash frame, said lower sash frame having a horizontal upper portion, a horizontal lower portion and two, opposite, vertical, side portions, said upper sash frame having a horizontal upper portion, a horizontal lower portion and two, opposite, vertical, side portions, said window assembly being closed when the lower sash frame horizontal upper portion is positioned adjacent the upper sash frame horizontal lower portion, comprising: a small magnet inserted into the upper sash; a sensor block installed on the lower sash horizontal upper portion, said sensor block having an internal raceway with a magnet slidably contained within; a magnetic alarm system adjacent said double hung window.