An agricultural working tool (10) for attachment to a tractor is provided. The tool, such as a tedder or planter, comprises a wheeled chassis (12) and a plurality of working units (14) mounted to a support frame (16). The support frame (16) comprises a centre frame (24) and a pair of side frame assemblies (28) and is foldable from an operating configuration to a transport configuration. The centre frame (24) is pivotably mounted to the chassis (12) about a transversely-extending first folding axis (26). Each side assembly (28) is pivotably mounted to the centre frame (24) about respective second folding axes (30) that extend in a substantially fore and aft direction when the support frame is in the operating configuration so that the side assemblies fold upwardly and inwardly about the second folding axes from the operating configuration. A linear actuator system (42) is operable between the chassis (12) and the centre frame (24) and is arranged to control movement of the centre frame about the first folding axis. The linear actuator system comprises a first linear actuator (44) between the chassis (12) and a rocker arm (50) which is pivotably mounted to the chassis (12) about a transverse pivot axis, and a second linear actuator (56,58) connected between the rocker arm (50) and the centre frame (12). The linear actuators may be provided by one or more hydraulic cylinders.
