Due to their compact construction, the hydraulic casing oscillators of the BV series are designed as front-end attachments to rotary drilling rigs. When mounted to the undercarriage of the drilling rig, the full torque of the casing oscillator can be transferred to the casing string and the weight of the drilling rig can also be activated as a reaction force to the vertical forces generated during installation of the casings. Exact setting up over the borehole position is facilitated by adjustment of the relative horizontal position between the casing oscillator and the drilling rig.