Disclosed is an object transfer device for a conveying installation, the device including a main object conveying path and a plurality of rotary drive elements, the rotary elements being configured to adopt a lowered position in which the element is situated below the main path a raised position in which the element projects above the main path in order to drive an object, the rotary drive element including drive surfaces with external diameters that vary over the length of the element, wherein the drive surfaces of the rotary drive elements have an external diameter that varies according to the angular position of the rotary element along the transfer path. Also disclosed is a conveying installation including such transfer device.