Patent ID: 7438663

Claim:
A compound gear system, comprising: a flexible gear comprising an articulating linear array of inner and outer gear elements disposed about middle gear tooth-engaging elements, the inner and outer gear elements each defining bottom profile regions; and a cylindrical rigid structure comprising spaced parallel ring arrays of first and second gear support structures projecting outward relative to a center axis, the first support structures each projecting an outward surface profile having sidewall ends, the first outward profiles conforming to one of the inner and outer gear element bottom profiles, and the second gear support structures each projecting an outward surface profile conforming to an other of the inner and outer gear element bottom profiles, the arrays spaced by a spacing distance greater than a tooth width of each of a plurality of gear teeth of a sprocket gear configured to engage the middle gear tooth-engaging elements; wherein the flexible gear is reeved tightly about the first support structures relative to the center axis and engaging the first support surface profile, the first support surface profile thereby restraining an engaged one of the inner and outer gear elements from moving inwardly relative to the center axis and the first gear sidewall ends, thereby restraining the engaged one of the inner and outer gear elements from moving rotationally relative to the center axis, the second gear outward profile surface aligning in conformance to an other of the inner and outer gear element bottom profiles, the gear support structures allowing the flexible gear to expand outward relative to the center point; and wherein the support structures are configured to transmit torque between the engaged flexible gear elements and the rigid structure responsive to interaction of the flexible gear middle tooth-engaging elements with said sprocket gear teeth disposed between the spaced gear support structure ring arrays and engaging the middle gear tooth-engaging elements.