play upon actuation of the electromagnet 39 for movement in a direction transverse to the longitudinal direction of the pulling rod 31 the ring 32 is made to abut the pulling rod 31 with sufficient friction to eliminate the play and thus inhibit movement of the pulling rod along its longitudinal direction the electromagnet 39 may be actuated for example by a non illustrated manually operated or foot operated pedal in the embodiment shown it is advantageous to increase the diameter of the pulling rod 31 so as to reinforce the same it will be understood that in lieu of a pulling ring 32 it would be equally possible to form the pulling rod 31 with a longitudinal recess and replace the ring 32 with a projection slidable with respect to the electromagnet 39 for example slidable therewithin another version of an electromagnetically actuated device according to the present invention is shown in fig2 c here the electromagnet 39 pushes for example wedge shaped means such as wedges 40 into a funnel shaped member 41 which surrounds the pulling rod 31 upon engagement of the wedges 40 with the funnel shaped member 41 further movement of the pulling rod 31 is inhibited depending on the polarity of the electromagnet 41 it is alternately possible for the wedges 40 to be lifted away from the funnel shaped member 41 when the electromagnet 39 is actuated in this latter embodiment the wedges.