A connecting device, in particular for installing at least one opening stay on a window leaf has a rail, which can be guided as far as possible in the direction of the first longitudinal axis thereof into a groove of the connecting device. The groove engages at least in sections behind the rail. The blocking of the longitudinal displaceability of the rail in the groove is guaranteed at least counter to the first longitudinal direction by a projection connected to the rail, which projection engages in a recess in the region of the groove. The projection is held in the installed position of the connecting device by a spring element in the recess. A spring element is arranged on the rail preferably in a limited movable manner. Alternatively or in addition, the connecting device can comprise a cap which holds the projection in the installed position of the connecting device indirectly and/or directly at least partially in the recess.

A concealed hinge for a turn-tilt window with a fixed frame and leaf includes of a pair of scissors with a first arm and second arm, that are connected by a central hinge and which are hingeably connected by a first end to a mounting slat that is intended to be mounted on the frame, and have a hinge at a second end for coupling to the leaf. The first arm is connected by its first end to the mounting slat with a fixed frame hinge with a peg fastened to the mounting slat and the second arm is connected by its first end to the mounting slat by a shiftable frame hinge with a peg that is shiftably affixed in a guide slot of the mounting slat, whereby in the closed situation of the scissors, the mounting slat serves as a support for the tilting movement of these scissors.

A concealed hinge for a turn-tilt window with a fixed frame and a leaf is provided with a scissor mechanism with a main arm having at a first end a hinge for fastening the concealed hinge to the top of the leaf, and is hingeably connected at a second end to a scissor hinge that is intended for the connection to the frame. The scissor hinge is composed of two scissor arms that are hingeable with respect to one another in such a way that the concealed hinge can be folded up. The main arm and the scissor arms extend above one another and parallel to one another in a horizontal direction. In the folded-up situation of the concealed hinge, when viewed vertically the main arm, with a section at the second end, is located above at least one of the scissor arms of the scissor hinge.

A connecting device, in particular for installing at least one opening stay on a window leaf has a rail, which can be guided as far as possible in the direction of the first longitudinal axis thereof into a groove of the connecting device. The groove engages at least in sections behind the rail. The blocking of the longitudinal displaceability of the rail in the groove is guaranteed at least counter to the first longitudinal direction by a projection connected to the rail, which projection engages in a recess in the region of the groove. The projection is held in the installed position of the connecting device by a spring element in the recess. A spring element is arranged on the rail preferably in a limited movable manner. Alternatively or in addition, the connecting device can comprise a cap which holds the projection in the installed position of the connecting device indirectly and/or directly at least partially in the recess.

A concealed hinge for a turn-tilt window with a fixed frame and leaf includes of a pair of scissors with a first arm and second arm, that are connected by a central hinge and which are hingeably connected by a first end to a mounting slat that is intended to be mounted on the frame, and have a hinge at a second end for coupling to the leaf. The first arm is connected by its first end to the mounting slat with a fixed frame hinge with a peg fastened to the mounting slat and the second arm is connected by its first end to the mounting slat by a shiftable frame hinge with a peg that is shiftably affixed in a guide slot of the mounting slat, whereby in the closed situation of the scissors, the mounting slat serves as a support for the tilting movement of these scissors.

A concealed hinge for a turn-tilt window with a fixed frame and a leaf is provided with a scissor mechanism with a main arm having at a first end a hinge for fastening the concealed hinge to the top of the leaf, and is hingeably connected at a second end to a scissor hinge that is intended for the connection to the frame. The scissor hinge is composed of two scissor arms that are hingeable with respect to one another in such a way that the concealed hinge can be folded up. The main arm and the scissor arms extend above one another and parallel to one another in a horizontal direction. In the folded-up situation of the concealed hinge, when viewed vertically the main arm, with a section at the second end, is located above at least one of the scissor arms of the scissor hinge.