Through spur gears 2 and 3, crossed helical gears 4 and 5, change gears 6 and 7, worm 8 and worm wheel 9, driving shaft 1 rotates drum 10 about fixed axis A-A. The curvilinear cam slot of drum 10 engages fixed pin 11 of the base. As a result, drum 10 and the whole head with the gearing travels along axis A-A.
$2801$CmG,SF$