PURPOSE: To enable an impact press work and facilitate synchronizing with the other device by providing a crank mechanism around the shaft of a flywheel turned by the frictional contact with a wheel at the driving side.

CONSTITUTION: A descending wheel 4 and an ascending wheel 5 are fixed in parallel on a shaft 3 freely movable on both sides. When the shaft 3 is shifted to one side and the descending wheel 4 is brought into contact with the flywheel 10 a shaft 9 turns. The shaft 9 is provided with an eccentric shaft part 16 and an upper wheel 17a of a tie rod 17 is fitted to the eccentric part. Since a below connecting ball part 17b of the tie rod 17 is connected to a ram 11, the ram is descended by the turn of the shaft 9. The lowering speed of the ram is controlled by a controlling cylinder 33 and its related mechanism and the energy of the flywheel 10 is released to the press work. When the press work is finished the ascending wheel 5 contacts with the flywheel 10 by the motion of the controlling mechanism and the shaft 9 turns reversely and the ram 11 is ascended by the crank mechanism.