Abstract: The apparatus comprises a pole (32), a C-shaped frame (34) fastened to one end of the pole (32) and having two branches (35, 36) substantially parallel to one another and an adjoining part (37) between the two branches, an extraction screw (40) engaged in an internally threaded hole passing through one branch (35) of the frame (34) and having one end forming a punch (50) directed towards lthe inside of the frame (34), and a means (43) for the remote actuation of the extraction screw (40) by screwing or unscrewing. The apparatus also possesses a centring ring (47) arranged round a smooth part of the extraction screw located between its threaded part and its end (50) forming the punch. Unscrewing is carried out by exerting a torque about the axis of the screw (16a) to be extracted, by means of the pole (32) and the frame (34), after the extraction screw has been tightened.