Patent ID: 7033295

Claim:
A chain tightener for chains having a first branch and a second branch, wherein alternate reversal of chain tension occurs between the first branch and the second branch so that one of the first branch and the second branch is tight while the other of the first branch and the second branch is slack, said chain tightener comprising a first supporting surface on the first branch of the chain and a second supporting surface on the second branch of the chain, with both supporting surfaces alternately acting as a tightening element on the chain branch currently being slack and each supporting surface being connected to a respective drive piston having an associated hydraulic circuit into which a fluid is fed for thrust in a tightening direction of the respective chain branch, with the hydraulic circuits of the two pistons being interconnected so that when any one of the pistons is thrust in a direction opposite to the tightening direction by the chain branch that is currently tight, said one piston sends the fluid of the associated hydraulic circuit into the other piston to thrust said other piston to tighten the other chain branch currently being slack.