Window opening and latching mechanism - has guide link arm connected to frame-mounted base plate via intermediary link arm

摘要

The mechanism is fitted on base plate (34) which in turn is screwed to the inner rabbet surface of the frame top section. The base plate carries control link arm (36), intermediary link arm (38) swivelling around fulcrums (40, 42) respectively. The control link arm (36) is provided with guide link arm (22) inform of a two-armed lever fitted to the control link arm by fulcrum (44). The frame-adjacent end of the guide link arm (22) is connected by fulcrum (46) to intermediate link arm (38) the far end of the guide link arm is connected to the stay arm (12) through fulcrum (48). The fulcrum (48) forms the pivotal point for the stay arm which is equivalent to the upper pivoting point for the window leaf. The return coupling of the swivelling motion of the stay arm (12) onto the control link arm (36) is effected by connecting link arm (50) connected also to the stay arm by fulcrum (52) and by fulcrum (54) to the control link arm (36).