Patent ID: 8141925

Claim:
A joint mechanism, comprising: a first link; a second link pivotally linked to the first link; a third link pivotally linked to the second link; a connecting member supported on the second link, the connecting member being constituted by an integrally formed shaft; a first worm and a second worm coupled to each other by the connecting member, each of the first worm and the second worm having a respective axis, each of the first worm and the second worm being rotatable about its respective axis, and each of the first worm and the second worm being movable in a direction along its respective axis; a first worm wheel in mesh with the first worm to pivotally move the first link with respect to the second link; and a second worm wheel in mesh with the second worm to pivotally move the third link with respect to the second link, wherein the joint mechanism satisfies a relation: dA×dB≧0 by rotation of the first worm and the second worm, and the joint mechanism satisfies a relation: dA×dB≦0 by movement of the first worm and the second worm in the direction along said respective axis, where A is an angle defined by the first link and the second link, B is an angle defined by the second link and the third link, dA is a change amount of the angle A, and dB is a change amount of the angle B.