a plurality of entrainment members can be individually summoned or called for by a release or summoning mechanism and can be individually and successively coupled at a substantially uniform spacing with respect to one another by a shuttle or transfer wheel with an endless revolving driven traction element . in order to reduce the technical constructional expenditure and the noise emission during operation of the clock conveyor there are provided magnetic devices for coupling the entrainment members in force - locking or frictional manner with the endless revolving driven traction element .