A link chain has alternating first and second links which are articulately connected to each other by universal joints. Each first link carries a gripper with a fixed jaw and a second jaw pivotable between first and second end positions through a dead-center intermediate position. Springs are provided to permanently bias each second jaw to either of the two end positions, and each second jaw is connected with a follower which can track a set of cams at two spaced-apart stations to move the second jaw between its end positions. Each link of the chain carries two shafts for pairs of roller followers which track the lateral edge faces of two flanges of an elongated guide rail having an H-shaped cross-sectional outline. The guide rail is bent and/or twisted, if necessary, to establish a helical, arcuate, looped and/or other complex path for advancement of successive links between the two stations. An additional follower of each link tracks the one or the other flange at one side of the web which connects the flanges of the rail to each other.