A baler (10) comprising a bale chamber (26)； a plunger (30) configured to compress crop material in said bale chamber (26) in order to form a bale； a needle yoke (42) with a plurality of needles (36) configured to deliver twine through said bale chamber (26)； a plurality of knotters (34) configured to receive the twine from said plurality of needles (36)； a bale length measurement and trigger device (150) configured to measure the length of the bale in the bale chamber (26) and to generate a trigger when a predetermined length is reached； a driving shaft (90) located above the bale chamber (26) and extending in a traverse direction of the baler (10)； a needle coupling device (100) between the driving shaft (90) and the needle yoke (42), said needle coupling device (100) being configured for moving said needle yoke (42) from a rest position to a twine delivery position and back, when said bale length measurement and trigger device (150) generates a trigger
