The Allais effect involves a change in the movement of a Foucault pendulum during solar eclipses (confirmed during the 1999 eclipse by a NASA experiment which did not led to an official communication) and it can in fact easily be explained by gravitons, the gravity particle. The passing of the Moon right in front of the Sun will deviate some gravitons from their original path between Earth and Sun, leading to a change in the movement of the pendulum. I am happy to find that I am not the only one to have had the idea : a quick Google search led me to an article about that by Clark M. Thomas.