This invention relates to excavations for diaphragms, in particular to the type including : a hydraulic bucket (16), at least one wire line (21) to lift and lower the bucket (16) along a vertical excavation axis (x), a telescopic guide group (13 - 15) to guide the bucket along the excavation axis, and a rotation device (31) to rotate the bucket around the excavation axis. The rotation device (31) is interposed between the telescopic guide group (13 - 15) and the bucket (16) ; the wire line (21) is fixed to an element (15) arranged upstream of the rotation device (31). The equipment includes flexible conduits (19) for bucket activation and winding paddle wheels (20) to wind the conduits around a horizontal axis. The paddle wheels (20) are also mounted on a non rotating structural element (13) arranged upstream of the rotating device (31).