Abstract: In a group of conveyor belts feeding articles to a manipulating machine, articles on a first belt are to be transferred to predetermined locations on a second belt. To obviate to incorrect positioning of an article on a first belt with respect to the second belt, affecting the transfer regularity, a digital signal representing the position of the second belt is stored whenever an article arrives on the first belt. An error signal is obtained from the stored signal whenever an incorrect positioning is detected, and is fed to members controlling the motion of the first belt to temporarily correct the belt speed and hence the position of the article with respect to the second belt. At each adjustment, the error signal is progressively reset by feedback signals.