A clockwise torque is applied through pinion 2 to escape wheel 1 which is rigidly mounted on shaft A. Balance wheel 3 oscillates with a period that is regulated by lever 4 and two pins a between which the external turn of hairspring 5 passes. Hollow balance staff 5 has a notch whose edges form the engaging and disengaging pallets. At each swing of balance wheel 3, a tooth of escape wheel 1, engaging an edge of a pallet, gives an impulse to the balance, thereby maintaining its oscillation.
$2746$RG,G$