There are many factors that drive the movement of tectonic plates on the surface of asthenosphere, and some of these factors have a larger contribution than others (e.g. slab suction).
One driving factor of less significance influencing tectonic plate movement is however the Earth's rotation. Apparently one such effect of the Earth's rotation is the "Pole flight force" which results in an equatorial drift of the plates to the equator.
Why does the rotation of Earth result in tectonic plates having a tendency to want to move closer to the equator?