after a lot of playing around with cams and ratchets i settled on using a simple ratchet and pawn mechanism to push the clock forward every 2 seconds. The balance wheel rebounded and tended to osculate , so i had to give it some time to settle down and thats why the 2 second period..

On hind sight if i have to do it again i would use a heavier balance wheel made out of steel or lead to get the wheel to oscillate slowly.