Patent ID: 8678195

Claim:
A screening bucket ( 1 , 100 ) comprising: a support structure ( 2 ) which can be secured to a moving arm of an operating machine, a screening drum ( 5 , 50 ) secured to the structure ( 2 ) so that the drum ( 5 , 50 ) is rotatable with respect to the structure ( 2 ) about an axis (X) of rotation, the drum ( 5 , 50 ) comprising at least one perimetral wall ( 6 a , 7 a ) provided with through holes ( 10 ) of dimensions such as to allow the passage of rubble of a predetermined size, a rotation unit for the screening drum ( 5 ; 50 ) that imparts a rotational motion to the drum ( 5 ; 50 ) about the axis (X) of rotation, a switching device ( 12 ) for the rotation unit, configured to switch the rotation unit between a first operating mode in which the screening drum ( 5 ; 50 ) is set in rotation at a substantially constant predetermined working speed and a second operating mode in which the rotation speed of the screening drum ( 5 ; 50 ) is reduced; the rotation unit further comprises a detector assembly ( 15 , 16 ) that detects an angular position of the drum ( 5 ; 50 ) and cooperating with the switching device ( 12 ) in such a way that the rotation unit is automatically brought into the second operating mode when the drum ( 5 ; 50 ) is in a region of at least one predetermined portion (A) of a revolution and is then brought back into the first operating mode when the rotation of the drum ( 5 ; 50 ) passes beyond the at least one portion (A) of a revolution.