HELICAL AND WORM GEARING MECHANISM WITH DWELLS OF THE DRIVEN WHEEL

Helical gear 1 rotates about fixed axis A-A and has helical teeth a only around a portion of its circumference. Over the rest of its circumference it has concentric projection b. Helical gear 2 rotates about fixed axis B and, in addition to helical teeth d, has equally spaced straight grooves e. The number of teeth a on gear 1 is equal to the number of teeth d on gear 2 between two adjacent grooves e. Gear 1 is keyed on driving shaft 6. To each revolution of shaft 6, gear 2 turns through a certain angle after which projection b engages one of the grooves e to prevent unintentional rotation of gear 2 during its dwell period. Gear 2 is keyed to shaft 7 on which worm 3 is also keyed. Worm 3 meshes with worm wheel 4 which rotates about fixed axis D. When driving shaft 6 rotates continuously, disk 5, rigidly attached to wheel 4, rotates intermittently with dwells. The angle of rotation of disk 5 and its rotation and dwell times depend upon the numbers of teeth on gears 1 and 2, and worm wheel 4, and the number of threads (starts) on worm 3.
$2826$WG,D$