Patent ID: 6234904
Filing Date: 2001-05-22
Classification: F16D

Abstract:
A drive power transmission apparatus arranged between a drive power source and a drive-power-receiving unit to transmit a drive power from a first rotatable element provided for the drive source to a second rotatable element provided for the drive-power-receiving unit, comprising:a power-transmitting face formed in a preselected one of the first and second rotatable elements to face toward a predetermined rotating direction of the preselected rotatable element;a torsionally deformable spring element provided with a first outer end arranged to be in a contact engagement with the power-transmitting face of the preselected rotatable element and a second outer end fixedly connected to the other of the first and second rotatable elements, said torsionally deformable spring element being torsionally deformed by a load torque appearing in the drive-power-receiving unit during transmission of the drive power while permitting a relative rotation between the first and second rotatable elements;an urging force applying means operative to apply an urge force to said first outer end of said torsionally deformable spring element in a direction to disengage said first outer end from said power-transmitting face;a blocking face formed in said preselected rotatable element to block said first outer end of said torsionally deformable spring element when said first outer end is urged by said urging force applying means to be disengaged from said power-transmitting face;a force releasing means for releasing the urging force of said urging force applying means when the load torque exceeds a predetermined limiting value, said force releasing means encouraging said torsionally deformable spring element to be torsionally deformed until said first outer end thereof is disengaged from said blocking face when the load torque exceeds said predetermined limiting value; andan elevation arranged in said preselected rotatable element for permitting said torsionally deformable spring element to ride thereon in response to the relative rotation between said first and second rotatable elements when said first outer end being disengaged from said blocking face cannot be separated from said preselected rotatable element by said urging force of said urging force applying means to thereby promote separation of said first outer end of said torsionally deformable spring element from said preselected rotatable element.