A positioning assembly (106) for a ram head (336) has a top surface for receiving impact pulses produced by a ram mechanism and a bottom surface for transmitting said impact pulses to a pile (102) with the purpose of driving said pile (102) into the ground or into a similar surface. The assembly comprises:
a first part and a second part. The first part defines an inner space for receiving said ram head (336) and exposing said top and bottom surfaces thereof and allowing said ram head (336) to transmit said impact pulses from said ram mechanism to said pile (102).The first part further has blocking means (342) for preventing said ram head (336) from being separated from said first part, and is fixatable to said ram mechanism.
The second part (330) is journalled rotatably relative to the first part round an axis of rotation, which is substantially coinciding with the longitudinal axes of said ram head (336) and of said pile (102).
The second part (330) further has fixation means for fixating said pile (102) in a specific and fixed rotational relationship relative to said second part (330). The assembly further comprises motor-drive means (300) co-operating with the first and second parts and has a first operational mode and a second operational mode.
The motor-drive means (300) generates in the first operational mode a rotational motion of said second part (330) relative to said first part round said axis of rotation, and generates in said second operational mode a fixation of said second part (330) relative to said first part preventing said second part from rotating relative to said first part round said axis of rotation.