Automatic safety clutch device for flexible drives

A grass cutter comprising an elongated curved, rigid arm, a drum rotatably mounted at the end of said arm, a cutting filament projecting from said drum, and means for rotatably driving said drum, said drive means comprising

• a flexible drive and automatic safety clutch assembly, said assembly comprising a flexible drive shaft connected at one end to a rotary power source and at the other end to a driven member for the transmission thereto of rotational torque from said power source, and means for automatically disconnecting said power source from said driven member in the event of an overload, said disconnection means comprising a socket member mounted for rotation by said flexible drive shaft, a socket axially formed in said socket member, said socket having a non-circular cross-section and axially engaging therein a complementary male member dirven by said shaft, the arrangement being such that upon said overload, reduction in the overall length of said flexible shaft caused by tendency of said shaft to curl up on itself is effective to withdraw said male member axially from said socket thereby to effect said disconnection, and
• other means for automatically guiding said male member back into said socket upon release of said overload thereby to re-establish the rotary drive connection therebetween.