Abstract: A lock 7 non-rotatingly and axially secures a coupling sleeve 6 to a power take off shaft 4 or driving journal 5 of a self driving implement or tractor 1. To achieve a clearance free rotatable and axial connection between the coupling sleeve 6 and power take off shaft 4 or driving journal 5, the locking element via at least one locking face 15, at least partially engages an annular groove 12 of the power take off shaft 4 or driving journal 5 to provide a clearance free connection. The locking element may be a bolt 16 with a conical locking face 15 to engage the angular groove 12.

Abstract: In an adjustable friction overload clutch for protecting the drive line between a power take-off shaft on a tractor and an agricultural implement, one or more Belleville spring washers bias plates and friction discs together. Adjustable bolts extend through the Belleville spring washer and are attached to the plate adjacent to the washer. Springs are held by the bolts and extend between the Belleville spring washer and a nut on the bolt. By adjusting the bolts, a variable torque can be set which is less than the maximum torque exerted by the Belleville spring washer when it is initially assembled on the clutch.