Abstract: A two-arm tensioning device is used to tighten and to lock load-fastening belts. The arms are pivotally mounted about a reel drum on which are mounted toothed discs which turn with the drum. Upon pivoting of the first arm the belt is wound onto the reel drum by the engagement of a first catch on the first arm with the teeth of the discs. A second catch on the second arm is provided to prevent, through its engagement with the disc teeth, turning movement of the drum in the opposite direction. The second arm includes a locking member arranged to releasably engage the first catch to prevent unintentional pivoting of the first arm after tightening of the belt. A special safety catch in the form of a projection is provided on the first arm to releasably retain the second catch in engagement with the disc teeth.