Cam drive mechanism for internal combustion engine

Claim 1

A mechanism for use in an internal combustion engine comprising a crank shaft and at least one cam shaft, said mechanism being designed to progressively vary the angular relationship of said at least one cam shaft relative to said crank shaft, and comprising a first disk provided with two radially extending cavities aligned with respect to each other, each of said cavities containing a spring-biased small weight slidably mounted therein, said spring urging said small weight towards the center of said first disk; means for connecting said first disk to said crank shaft to cause said first disk to be driven by said crank shaft; a second disk coaxially mounted with respect to said first disk, said second disk being provided with two arcuated slots of identical curvatures, said slots being symmetrical with respect to the center of said second disk and extending from a short distance away from said center towards the periphery of said second disk in opposite directions; means for connecting said second disk to said at least one cam shaft to cause said cam shaft to rotate at the same speed as said second disk; and connecting pins integral with said small weights, said pins being engaged into the arcuated slots and free to move therein so as to drive into rotation said second disk when the first disk rotates; wherein, when the rotation speed of the crank shaft varies, the small weights radially sliding in the cavities of the first disk under the action of the centrifugal force, and cause the pins connected thereto to move along the arcuated slots of the second disk and thus to progressively vary the angular relationship of the second disk with respect to the first disk.