An internal combustion engine enabling asymmetric port timing has an engine mechanism including a crankshaft having a crankpin to which each piston of an opposed pair of pistons is connected and by which the pistons are reciprocatable in a respective one of axially inline cylinders. The mechanism also includes a crosshead having opposite ends on each of which a respective piston is mounted, and a coupling between the crosshead and the crankpin by which the pistons are caused to oscillate circumferentially as the pistons are driven to reciprocate.

An example device may include a rounded outer incline ramp and a rounded inner incline ramp surrounding a central axis. The rounded inner incline ramp and the rounded outer incline ramp may be inversely aligned relative to the central axis. The device may also include a piston carrier oriented in a direction parallel to the central axis. The piston carrier may include a first piston including a first roller positioned on the two ramps at a first point, where the first piston is configured to act on the two ramps in a direction parallel to the central axis. The piston carrier may also include a second piston including a second roller positioned on the two ramps at a second point opposite the first point, where the second piston is configured to act on the two ramps in a direction parallel to the central axis.

An example device may include a rounded outer incline ramp and a rounded inner incline ramp surrounding a central axis. The rounded inner incline ramp and the rounded outer incline ramp may be inversely aligned relative to the central axis. The device may also include a piston carrier oriented in a direction parallel to the central axis. The piston carrier may include a first piston including a first roller positioned on the two ramps at a first point, where the first piston is configured to act on the two ramps in a direction parallel to the central axis. The piston carrier may also include a second piston including a second roller positioned on the two ramps at a second point opposite the first point, where the second piston is configured to act on the two ramps in a direction parallel to the central axis.

A nutating cam shaft speed reducer includes multiple cams and rolling or sliding surfaces to create a high reduction ratio, high torque speed reducer in a small space. The nutating cam speed reducer may be made predominantly from plastic. The nutating cam speed reducer may be made to work in concert with a motor, wherein the motor is also made using a high percentage of plastic. The motor may feature an integrated control printed circuit board. The nutating cam speed reducer and motor may be integrated into a robot arm, and the robot arm may be centrally cooled using a technique wherein airflow is routed through an axial center of the robot arm and back out along a perimeter of the robot arm. The airflow cools power electronics, the nutating cam speed reducer, and a motor stator such that higher power levels are possible than without active cooling.

A nutating cam shaft speed reducer includes multiple cams and rolling or sliding surfaces to create a high reduction ratio, high torque speed reducer in a small space. The nutating cam speed reducer may be made predominantly from plastic. The nutating cam speed reducer may be made to work in concert with a motor, wherein the motor is also made using a high percentage of plastic. The motor may feature an integrated control printed circuit board. The nutating cam speed reducer and motor may be integrated into a robot arm, and the robot arm may be centrally cooled using a technique wherein airflow is routed through an axial center of the robot arm and back out along a perimeter of the robot arm. The airflow cools power electronics, the nutating cam speed reducer, and a motor stator such that higher power levels are possible than without active cooling.