The crimping head (2) is pivoted to a horizontal arm (4) by its upper part, said arm being mounted at the end of a support rod and pivoting on a central vertical post (12). This arm allows the head to adopt a position in which it is inclined towards the front of the machine as a result of the action of a small jack (5), in such a way that its lower end is moved away from the shaped fixed contact (6) which holds the hanging attachment in place on the support board (1). The invention is suitable for fitting the hanging attachments on the backs of frames.