Patent ID: 8082891

Claim:
An engine assembly which includes an internal combustion engine having an output member which is pivotally reciprocable about a prime pivot axis; an output shaft which is rotatable about a rotational output axis; a conversion mechanism whereby the output member and the output shaft are drivingly connected together; and a worm gear mounted to the output shaft and which is in drive communication with at least one intake and at least one exhaust valve associated with the internal combustion engine, and wherein the conversion mechanism is operable to convert pivotally reciprocating motion of the output member about the prime pivot axis into rotational motion of the output shaft about the rotational output axis, the conversion mechanism including: a cam housing which is fastened to the output member for movement about the prime pivot axis and which is pivotally displaceable relative to the output member about a cam axis which is transverse to the prime pivot axis, the cam axis being movable with the output member about the prime pivot axis, the cam housing defining at least one cam member; and a cam follower on the output shaft, the cam follower having a wobble axis which is tilted or inclined relative to the rotational output axis, the cam member of the cam housing being in pivotally reciprocating engagement with the output member and being operable to engage the cam follower, thereby to convert the pivotally reciprocating motion of the output member to rotational motion of the output shaft about the rotational output axis, and wherein the cam housing defines a passage though which the output shaft passes, and the cam housing provides the cam member in the form of two opposed cam faces which are parallel and are spaced along the wobble axis, the cam faces sandwiching a wobble disc between them so that the wobble disc is parallel to both the cam faces, and including a low-friction interface between the wobble disc and the cam faces, the low-friction interface comprising a pair of thrust bearings which are co-axial with both the cam faces and the wobble disc, the thrust bearings being located on opposite sides of the wobble disc for bearing against the cam faces.