Abstract: A panel assembly for a door or window including a generally quadrilateral frame member having a panel member operatively connected therewith for movement between a closed position and opened positions wherein the frame member is either tilted about one edge thereof or moved laterally offset parallel to itself. Latch means provided between the panel member and the quadrilateral frame include at least one releasing arm and an angular housing, with the angular housing being connected at a corner of the panel member with two adjacent members thereof and with the releasing arm having a panel-side end at which the releasing arm is connected with the angular housing.

Abstract: A closure panel assembly including a frame member and a panel member adapted to be tilted relative to the frame member and also laterally offset relative thereto by movement parallel to itself is equipped with a panel latching mechanism which includes a locking member engaging between the panel member and the frame member to lock the lower end of the panel member relative to the frame member when the panel member is to be moved to its tilted position while enabling release of the lower end of the panel member when the panel member is to be parallel laterally offset.

Abstract: A room ventilator structured to define therethrough both a primary airstream and a secondary airstream arranged in heat exchange relationship with each other. A heat exchanger located to have both said primary and secondary airstreams flow therethrough is structured to divide both of said streams into numerous smaller partial airstreams with walls made of high thermal conductivity intermediate the partial airstreams to enhance the heat exchange capacity between the streams. The heat exchanger is designed so that it may be installed in the ventilator in a plurality of reversed positions without impairing its function.

Abstract: A sash is mounted in a first position in a fixed frame and is movable laterally into a second position where it is parallel to the first position. A plurality of swing arms connect the sash to a movable carriage so that in the second position the sash can be moved along a linear path between a closed position and open position relative to the first position of the sash in the fixed frame. At least one of the swing arms has a control arm pivotally attached to it. The control arm has a locking member engageable within and movable along a slot in the carriage. The locking member can be secured within a section of the slot angularly offset from the main section of the slot when the sash is in the second position. With the locking member secured in the angularly offset section, the sash is retained in the second position. A lug secured to the fixed frame is located in the path of the carriage as the sash moves along the linear path toward the closed position.