40 3 the axis of rotation 40 4 of which is oriented perpendicular to the pressing devices 41 and extends horizontally such the pressing devices 41 quasi revolve overhead in a vertical plane the joint forming devices 42 are also situated on the rotor 40 3 and rotate together with the pressing devices 41 their joint forming rails 42 1 essentially extend radially referred to the axis of rotation 40 4 of the rotor the binding in machine is designed such that the books 1 are continuously held in one and the same pressing device 41 and that the joint forming rails 42 1 heated by means of heating rods can be continuously held in the closed position so as to realize a gentle joint forming process the pressing devices 41 are formed by a pair of opposite pressing plates 41 1 that are spaced apart by a variable distance and can be set into an open position 41 11 a guiding position 41 12 and a clamping position 41 13 symmetrically above the book center while being accommodated on the actuating arms 41 2 the actuating arms 41 2 are guided in a guide rail 41 3 fixed on the rotor 40 3 the control means for the actuation of the actuating arms 41 3 and therefore the pressing plates 41 1 may consist of pneumatic hydraulic or electric driving means or engage into mechanical cam plates a specific design is not illustrated in the figures in order to provide a better overview the joint forming rails 42 1 of the joint forming devices 42 are accommodated on actuating arms 42 3 that are displaceably guided in guide rails 42 4 fixed on the rotor 40 3 and actuated symmetrically above the book center with.