A post driver (1) has a support frame (2) with means (3) for attachment to a carrier vehicle. A mast (4) is mounted on the support frame (2). A hammer (5) is slidably mounted on the mast (4) for movement between raised and lowered positions on the mast (4). A hammer actuating assembly (8) is operable for raising the hammer (5) on the mast (4) for release to drive a post. The hammer actuating assembly (8) has a hammer lifting rope (10) having a first end (11) attached to the hammer (5) and a second end (20) attached to the mast (4), said rope (10) extending outwardly from the hammer (5) and around a fixed pulley (15) which is rotatably mounted on the mast (4) and then downwardly and around a movable pulley (18) and then upwardly to an anchor point (19) on the mast (4) to which the second end (20) of the rope (10) is attached. Drive means (26) is operable for moving the movable pulley (18) away from the fixed pulley (15) for raising the hammer (5). The movable pulley (18) is rotatably mounted on a carriage (25), said carriage (25) slidably engaging the mast (4). The drive means (26) is a ram connected between the carriage (25) and a ram mount (29) on the mast (4) below the carriage (25).
