Patent ID: 7866237

Claim:
Screwing head ( 1 ) for screwing a ring nut ( 2 ) of a trigger on a vessel comprising: a. an upper body ( 1 b ) and a lower bell ( 1 c ) adapted to be rotated together around a rotation axis ( 1 a ) by a rotating permanent magnet-type clutch ( 12 ), that is inserted in said upper body ( 1 b ), b. four rollers ( 5 ) placed around the respective vertical axes ( 4 a ) of four vertical arms ( 4 ), said vertical arms ( 4 ) being capable of simultaneously being oscillated in order to bring said four rollers ( 5 ) from an open position to a tightening position around the ring nut of the trigger, c. a hollow shaft ( 10 ) inserted in the upper body and in the lower bell, d. a first stem ( 11 ), housed inside said hollow shaft ( 10 ) which vertically translate along axis ( 1 a ); a terminal part of said first stem ( 11 ), that is located towards a base ( 1 d ) for closing said lower bell ( 1 c ) said terminal part ending with four forks ( 8 ) having four recesses which house pins ( 13 ), e. a second stem ( 14 ), inside said vertical arms ( 4 ) that are connected with an end part of said hollow shaft ( 10 ), in which a toothed crown ( 16 ) is keyed to and engages a corresponding ball-shaped toothing ( 15 ) mounted on a bulb ( 14 a ) of said second stem ( 14 ), opposite to said end part of said second stem ( 14 ) which is connected to roller ( 5 ) wherein an action imparted by said first stem ( 11 ) causes said second stem ( 14 ) to rotate by a corresponding vertical arm ( 4 ), making rollers ( 5 ) radially open, said rollers ( 5 ) being detachable from ring nut ( 2 ).