Window assemblies

Claim 1

A WINDOW ASSEMBLY COMPRISING A GENERALLY RECTANGULAR FIXED FRAME ENCLOSING AN APERTURE AND COMPRISING SPACED VERTICAL SIDE FRAME MEMBERS AND HORIZONTAL TOP AND BOTTOM FRAME MEMBERS; A VENTILATOR OF THE CASEMENT TYPE ARRANGED TO OPEN AND CLOSE THE APERTURE AT WILL, SAID VENTILATOR COMPRISING A RECTANGULAR MOVABLE FRAME HAVING SPACED VERTICAL SIDE EDGES; A STRAIGHT CONTINUOUS VERTICAL SHAFT HAVING CONTINUOUS ROTARY BEARING WITHIN ONE OF SAID SIDE EDGES AND EXTENDING THE FULL LENGTH THEREOF, AND MEANS FOR GUIDING SAID OPPOSITE UPPER AND LOWER END PORTIONS FOR SLIDING MOVEMENT WITHIN THE TOP AND BOTTOM FRAME MEMBERS OF SAID FIXED FRAME; MECHANISM OPERATIVELY CONNECTING SAID SHAFT ENDS RESPECTIVELY WITH SAID TOP AND BOTTOM FIXED FRAME MEMBERS FOR MAINTAINING SAID SHAFT AXIS, AND CONSEQUENTLY SAID MOVABLE FRAME, IN TRUE VERTICAL AND NON-SAGGING POSITION THROUGHOUT THEIR MOVEMENT IN THE FIXED FRAME, REGARDLESS OF THE DISPLACEMENT OF THE CENTER OF GRAVITY OF THE MOVABLE FRAME OUTWARDLY OF THE CONFINES OF THE FIXED FRAME; AND A LINK ARRANGED TO RESTRICT THE MOVEMENT OF THE MOVABLE FRAME, SAID LINK HAVING ONE OF ITS ENDS PIVOTALLY CONNECTED ON A VERTICAL AXIS TO ONE OF THE HORIZONTAL FRAME MEMBERS OF THE FIXED FRAME AT A POINT WITHIN THE PLANE OF SAID FIXED FRAME, AND THE OTHER END PIVOTALLY CONNECTED ON A VERTICAL AXIS TO AN INTERMEDIATE PORTION OF THE MOVABLE FRAME; THE AXES OF SAID TWO PIVOT POINTS AND THAT OF SAID SHAFT BEING PARALLEL AT ALL TIMES AND DISPOSED SUBSTANTIALLY IN A COMMON VERTICAL PLANE PARALLEL TO THE PLANE OF THE FIXED FRAME WHEN THE MOVABLE FRAME IS IN CLOSED POSITION.