A serial printer comprises a carriage 32 movable parallel to a platen 14 and on which there is mounted a printing device 31, for example of the daisy wheel type. The guides 23, 25 on which the carriage slide are mounted on a frame 20 which can turn with respect to the fixed sides of the machine on pivots 16, 17 to allow easy replacement of the daisy wheel. A motor 70 located beneath the roller constituting the platen effects displacement of the carriage along the writing line by means of a steel cable 72 and a series of return pulleys 44, 45, 75, 82. The cable passes through coaxial holes 74, 84 in the pivots of the frame, in such a way that its conditions are not altered when the frame is turned. A unidirectional clutch 86 and a spring 89 coupled to one end 88 of the cable maintain the tension in the cable always constant, while providing a non-yielding anchorage when the motor pulls on that end of the cable.