Gear assembly adapted for mating with a third gear without backlash

Claim 1

A gear assembly adapted for mating with a third gear in a non-backlash manner, said assembly comprising: first and second circular gears arranged so as to be coaxially and relatively rotatable, said gears having peripheral teeth with identical tooth profiles and having inner surfaces opposing each other; first and second pin means standing on the inner surface of the first gear; a spring having a generally arcuate shape with first and second ends and having first and second hole means adjacent to the respective ends thereof, said spring being carried by said first gear in a prestressed state by said first and second pin means engaged with said respective first and second hole means at each end of the spring, at least said first hole means having a dimension, taken circumferentially of the assembly, greater than that of the associated first pin means so that said spring can be elastically deformed by application of a force to said spring at the first end thereof; and a wall means on the inner surface of said second gear for defining a groove to cover said spring at least partly in the axial direction of the assembly, a part of said wall means abutting against said one end of said spring to cause elastic deformation to said spring, said first and second gears together being adapted to mate with the common third gear under the elastic deformation of said spring to provide non-backlash mating with said third gear.