Locking mechanism for sash type windows

A locking mechanism for a window having a window frame including a guide groove extending in movement directions, and upper and lower sashes at least one of which is slidable with respect to said frame in said movement directions, each of said sashes having a meeting rail, said meeting rails adapted to lie adjacent one another when said sashes are in a closed position, said locking mechanism comprising

• at least one sash clamp connected to one of said meeting rails,
• at least one receiving element corresponding to said at least one sash clamp connected to the other of said meeting rails,
• a locking element disposed at an end of said one of said meeting rails and adapted in an extended position to lie within said guide groove,
• a handle moveable between a locked position, an unlocked position and a release position, and
• an operating mechanism including means for engaging said locking element with a wall of said guide groove and for engaging said at least one sash clamp with said at least one receiving element responsive to movement of said handle from said unlocked position to said locked position, said operating mechanism also including means for disengaging said locking element from said wall of said guide groove and for disengaging said at least one sash clamp from said at least one receiving element responsive to movement of said handle from said locked position to said unlocked position, said operating mechanism further including means for retracting said locking element from within said guide groove responsive to movement of said handle from said unlocked position to said release position.