Overload coupling

摘要

A device for transmitting rotational power from a rotational power source to a driven device having a drive shaft includes at least one elastic connecting member (15) defining outer and inner peripheral surfaces. First and second holder members (12,13) radially cooperate with each other to circumferentially hold the at least one elastic connecting member (15) during normal operation to transmit the rotation, and are disconnected by the deformation of the at least one elastic connecting member when the torque on the drive shaft exceeds a predetermined cutoff torque level. A weakened portion is provided at least one of the first and second holder members. The weakened portion aids the deformation of at least one of the first and second holder members to reduce a torsional spring coefficient which is defined by the ratio of the relative rotational angle between the first and second holder member to the torque on the drive shaft.