Patent attributes
A clutch mechanism has rotational driving force outputting members connected to a rotational driving force input system, rotational driving force receiving members connected to a rotational driving force output system, and a pressing mechanism for pressing the rotational driving force outputting members against the rotational driving force receiving members to keep the rotational driving force outputting members and the rotational driving force receiving members in contact with each other. The pressing mechanism has a constant load applying means and a variable load applying means for together generating the pressing force which brings and keeps the rotational driving force outputting members and the rotational driving force receiving members in contact with each other. A value of a load generated by the constant load applying means being set to be less than the maximum non-slide limit, i.e., the maximum of the non-slide limit which is required for keeping the rotational driving force outputting members and the rotational driving force receiving members in contact with each other to transfer the rotational driving force.