Abstract: A device is provided to join the lower end of a strip of paper coming from a nearly-empty reel to the upper end of another strip of paper coming from a full reel. The joining device comprises a rotating striking arm equipped with a hammer on one of its ends and with a cam on the other end. When the join between two strips is to be made, a jack actuates a castor which butts against the cam, thus bringing a striking surface of the hammer closer to the strips to compress and join the strips. The device further comprises a front and a rear cutting fixture permitting the remaining ends of the strips of paper to be cut on either side of the join. Air bearings are provided to guide one or both strips.