Abstract: A coupling assembly for rotatably coupling two shafts comprises a first shaft extending longitudinally between a first end and a second end and having a radially extending flange at said second end; a second shaft extending longitudinally between a first end and a second end and having a radially extending hollow receiving member at said first end, the flange being positioned within the hollow receiving member, The hollow receiving member comprises an inner cylindrical surface comprising at least one longitudinally extending member groove and the flange comprises an outer cylindrical surface comprising at least one longitudinally extending flange groove, The coupling assembly also includes a barrel-shaped roller bearing provided to extend longitudinally within and in contact with both said flange groove and said receiving member groove and the flange groove and/or said member groove has a longitudinal concave barrel shape for receiving and contacting said barrel shaped roller bearing.

Abstract: A torque limiting assembly is disclosed comprising: an input shaft; an output shaft; a drive bush; a motion converter mechanism; a casing; and at least one engagement member for engaging the casing. In a low torque mode, rotation of the input shaft drives rotation of the drive bush, motion converter mechanism and output shaft. In a high torque mode, rotation of the motion converter mechanism relative to the output shaft urges the motion converter mechanism axially to drive rotation of the drive bush relative to the input shaft. The engagement member is coupled to both the drive bush and the input shaft such that when the drive bush is rotated relative to the input shaft, the engagement member is urged to engage the casing so as to prevent or inhibit rotation of the input shaft relative to the casing.