versa in such a way not any of the pairs of hooks 150 151 conforming the coupling means can make a displacement in the longitudinal direction relative to the rotation axis of the device in any direction moreover because the symmetric disposition in two planes practically it is impossible that the coupling means are unnoticeable detached and they just can be detached applying a force with magnitude and direction appropriate on the four pairs of hooks simultaneously all of this offers the set a superior stability in its configuration with respect to devices known in the art in a second embodiment shown in fig4 to 7 it is observed that the device 200 is made in the same way that in the first embodiment illustrated in fig1 to 3 with an external ring 210 essentially right cylinder shaped an internal ring 220 essentially right cylinder shaped too located concentrically in relation to the external ring 210 maintained in such concentric relation by means of a plurality of union elements 280 essentially formed by constant width strips going from the external face of the internal ring 220 towards the internal face of the external ring 210 however in this embodiment the width of the union elements 280 increases from the external ring 210 up to its maximum in the.