A tensioning device for a chain driven jaw system in a package filling machine is disclosed. The chain driven jaw system has a fixed cam and a chain as a follower. The tensioning device comprises a chain tensioning element shaped and angled so to receive the chain on an outer surface thereof configured to be directed away from a center of the chain driven jaw system, wherein the chain tensioning element comprises a pivot connection, and wherein the chain tensioning element is configured to be integrated with the fixed cam at the pivot connection such that the chain tensioning element abuts the fixed cam at the pivot connection and can move to tension the chain. A chain driven jaw system and a related method is also disclosed.