Driveline coupling with safety interlock mechanism latchable in the open position

Claim 1

A coupling assembly including a lock latchable in the unlocked position particularly for connecting a universal shaft for driving an agricultural implement with a power takeoff shaft of a tractor comprising: a coupling sleeve having an axial bore defined therein adapted to receive in torque transmitting engagement a power takeoff shaft having an annular grove formed therein; radial apertures defined in said coupling sleeve; locking members received in said radial apertures for engaging in an annular groove formed in a power takeoff shaft received in said axial bore for effecting locked engagement between said power takeoff shaft and said coupling sleeve; said coupling sleeve being adapted to be brought into locked engagement with a power takeoff shaft by movement relative thereto in a slip-on direction and to be brought into an unlocked position by movement in an opposite direction; a lock ring engaging about said locking members to hold said coupling assembly in locked engagement; a gripping sleeve connected with said lock ring; a resilient spring washer having an axial slit formed therein enabling said spring washer to expand and contract radially; a first conical face formed on the side of said spring washer mating with a first complementary conical face formed on said gripping sleeve; a second conical face on said spring washer on the side thereof opposite said first conical face mating with a second complementary conical face formed on said coupling sleeve; a cylindrical seating face formed on said coupling sleeve adjacent said second complementary conical face; and a cylindrical inner bore formed on said spring washer adapted to seat on said cylindrical seating face when said washer is radially expanded by being urged by said gripping sleeve against said second complementary conical face to place said coupling assembly in an arrested unlocked position.