Line of Contact, ANSI/AGMA 1012-G05
A line of contact is a line or curve along which two tooth surfaces are tangent to each other.
Plane of Action, ANSI/AGMA 1012-G05
The plane of action is the surface of action for involute, parallel axis gears with either spur or helical teeth. It is tangent to the base cylinders.
http://en.wikipedia.org/wiki/Worm_drive - това е за обща култура, тъй като има твърде голям брой и видове предавки за редуктори... Всички видове редуктори използуват "червячна" предавка (която "редуцира, намалява"...