and the gear 65 in the embodiment illustrated are formed integrally and suitably affixed to the shaft 15 as shown in fig2 and 4 a spring 131 acts between the print disc pinion 51 and the cover 89 to preload the bearing 91 the timing pinion 67 and the plate 81 are formed integrally and mounted on the shaft 71 which in turn is mounted on the bottom wall of the housing 88 as shown in fig4 the fly weights 83 are pivotally mounted on and beneath the plate 81 and a peripheral surface of a well integrally formed in the bottom wall of the housing 88 defines the drum surface 85 the diode 75 and the photocell 77 are mounted in a housing 133 which is attached to the peripheral wall of the housing 88 as shown in fig3 and 4 the stop 53 is carried on the lower face of the print disc 13 fig4 and 6 in fig4 the print disc 13 is rotated to show the stop 53 the main pawl 55 is pivotally mounted by a pin 135 on the cover 89 immediately below the print disc 13 the main pawl 55 has an upwardly projecting flange 137 which extends upwardly through a slot 139 fig4 in the cover 89 so that the flange can contact the stop 53 the electromagnetic means 57 may take the form of a normally de energized solenoid which normally holds the main pawl 55 in a locking.