The present invention provides embodiments of an agricultural baler (1) comprising a bale case (3), having a wall portion with an entrance opening (15) for the introduction of crop material; a plunger (13), disposed for movement in the bale case to thereby compact said crop material into bales; a duct (19) for the transportation of said crop material to said entrance opening; and a stuffer unit (37), operable associated with said duct and comprising a fork assembly. The stuffer unit comprises tines (43); and a drive mechanism (75,175,275,375) acting on the fork assembly. The drive mechanism comprises: a first drive member (77,105) configured for a reciprocating motion along a path of movement and operatively connected to a power source of the baler; a second drive member (71, 107) configured for a reciprocating motion along the path of movement of the first drive member and operatively connected to the fork assembly; and a selectively operable coupling arrangement (83) configured for selectively coupling the
